Category Archives: Pressure Measurement Sloutions

Intrinsically Safe vs Explosion Proof Pressure Transmitters

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Intrinsically safe vs explosion proof is a common function of pressure transmitters. When pressure transmitters need to be used in high-risk and explosive places, you must know it!

Intrinsically Safe vs Explosion Proof Pressure Transmitters

The explosion-proof pressure transmitter is divided into: intrinsically safe pressure transmitter (explosion-proof mark Exia ⅡC T6 Ga), explosion-proof pressure transmitter (explosion-proof mark Exd ⅡC T6 Gb). Intrinsically safe pressure transmitters must be used with safety barriers. The connection terminals of explosion-proof pressure transmitters must have an explosion-proof electrical connector box and a solid shell.

Sino-Inst offers a variety of  explosion-proof pressure transmitters. If you have any questions, please contact our sales engineers.

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More Pressure Sensors

Intrinsically Safe vs Explosion Proof

It is often necessary to use explosion-proof instruments in industrial sites. The general industrial explosion-proof instruments are mainly explosion-proof and intrinsically safe. So, how to understand the difference between them?

Different from the design concept:

Flameproof definition:

It can withstand the explosive pressure of internal explosive gas mixture. And can prevent the internal explosion from spreading to the explosive mixture around the enclosure of electrical equipment enclosure (zone I explosion-proof technology).

Dangerous gases are allowed to enter the flameproof enclosure, which may cause an explosion. However, the enclosure must have sufficient strength. And each shell joint surface must have a sufficiently long engagement length and a sufficiently small gap. To ensure that the internal explosion will not pass through the flameproof joint and cause the external environment to explode.

Clearance explosion-proof technology. Rely on the gap and mesh length to achieve the effect of cooling and flameout.

Definition of intrinsic safety:

Any electric spark or any thermal effect generated under the conditions specified in the standard (including normal operation and specified fault conditions) cannot ignite the circuits in the specified explosive gas environment (Zone 0/I explosion-proof technology).

It is a “safe” technology that uses suppression of ignition source energy as an explosion-proof method. It is required that the electric spark or thermal effect that the equipment may produce under normal operation or failure state are respectively less than the minimum ignition energy and self-ignition temperature of the explosive dangerous gas. For example: hydrogen 19uJ 560℃.

Intrinsically safe technology is actually a low-power design technology. Therefore, it can be well applied to industrial automation instruments.

Read more about: What Is the Difference Between Class 1 Div 1 and Class 1 Div 2 ?

Different from the application area

Explosion-proof applicable area: It can only be installed in hazardous locations in Zone 1 or Zone 2.

Intrinsically safe application area:

Exia: Equipment that can maintain explosion-proof performance until two components or other types of failures. Intrinsically safe equipment can be installed in hazardous locations in Zone 0, Zone 1, and Zone 2. Exia intrinsically safe equipment is the only explosion-proof electrical equipment that can be installed in zone 0.

Exib: Equipment that can maintain explosion-proof performance until a component or other type of failure. Intrinsically safe equipment can be installed in hazardous locations in Zone 1 and Zone 2.

Explosion Proof Pressure Transmitter

SIEP489 Explosion proof pressure Transmitter is a microprocessor-based high-performance transmitter. SIEP489 has flexible pressure calibration, push button configuration, and programmable using HART® Communication. We also supply industrial pressure sensors, and explosion proof differential pressure transmitter.

All our electronic pressure transducers can be offered with Explosion-proof. Select explosion-proof pressure transmitters with Ex d certification and 4-20mA output signals for installation. These installations require the use of equipment and enclosures designated as containing internal explosives. This prevents ignition of the explosive environment surrounding the equipment ( Specified) Flameproof area.

The application range of explosion-proof pressure transmitter is as follows:

  1. Natural gas control system natural gas compressor dispenser;
  2. Oil well platform wellhead pressure equipment blowout preventer pipeline equipment mine;
  3. Storage and transportation monitoring of oil tanks and oil products, petrochemical equipment, oil refining;
  4. Oxygen transmission system and pipeline, hydrogen equipment;
  5. Power stations, boilers, thermal power units, etc.;
  6. Petrochemical environmental protection air compressor light industry machinery metallurgy;
  7. Other pressure measurement environments with explosion-proof requirements.

Of course, intrinsic safety and explosion-proof are not limited to pressure transmitters. Other industrial instruments have this function. To ensure the use of users in dangerous and harsh environments.

More Featured intrinsic safety and explosion-proof sensors

Hygienic / Sanitary Pressure Transmitter
Also called Hygienic pressure Transmitters, or tri clamp pressure transmitter. Sanitary pressure Transmitters is used to food &beverage or pharmaceutical application.
High-Temperature Pressure Transmitter
High-temperature pressure transmitters with a 4-20mA output.
which has a temperature capability of over 850 °C and is not pyroelectric.
Absolute Pressure Transmitter
Absolute pressure transmitter with 4-20mA output for measuring pressure with absolute type reference. Absolute pressure (AP) transmitter is a measure of the ideal (complete) vacuum pressure.
Hydrostatic pressure transmitter
Hydrostatic pressure transmitter is used for fluid hydrostatic pressure measurement. With working static pressure up to 32Mpa, for liquid, gas or steam .
LD series Rigid Probe Magnetostrictive Level Transmitter
LR series Integral flange Magnetostrictive level sensor
LT series Digital Display Magnetostrictive liquid level sensor
LP series Magnetostrictive Tank Level Indicator-PVDF/ PPH/ PTFE/ PFA/ PP

Sino-Inst offers a variety of Intrinsically Safe vs Explosion Proof Pressure Transmitters for industrial pressure measurement. If you have any questions, please contact our sales engineers.

How to Calibrate a Pressure Transmitter

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What is Calibrate a Pressure Transmitter?

Calibrate a Pressure Transmitter is an important step to help pressure transmitters make accurate measurements. Only when the input and output are debugged together can it be called a true calibration. Including the pressure of the input transmitter, A/D conversion circuit, and loop current output circuit.

Pressure transmitter calibration is what you need to do before you install the pressure transmitters.

Technical Support Pressure Sensors

Pressure Sensor Calibration Case Share. The customer purchased a batch of high-frequency dynamic pressure sensors from our company. According to customer requirements, the accuracy of our pressure sensor is ±0.25% FS.

After the pressure sensor was produced, it was delivered to a third-party inspection company. The accuracy of the high-frequency dynamic pressure sensor was verified. As a result of the verification, the accuracy of our high-frequency dynamic pressure sensors has reached ±0.20% FS, and a calibration certificate is attached.

About High-Frequency Dynamic Pressure Sensor

The customer purchased our SI-90 high-frequency dynamic pressure sensor.

SI-90 High-Frequency Dynamic Pressure Sensor

The use of micro-machining technology makes the effective size of integrated silicon chips small, high natural frequency, and excellent elastic properties. Comprehensive performance is better than piezoelectric dynamic pressure sensors. It is the first choice for dynamic pressure measurement.

Measuring range

-100KPa~0~1KPa…20KPa…100MPa

Overload capacity

2 times full scale pressure (where the overpressure of 100MPa product is 1.1 times full scale pressure)

Type of pressure

Gauge pressure or absolute pressure

Measuring medium

Gas or liquid compatible with 316 stainless steel

Comprehensive accuracy

±0.1 %FS

±0.25%FS

±0.4%FS

Natural frequency

150KHz~700KHz

500KHz~1MHz

1MHz~2MHz

Transmitter bandwidth

0~1KHz~3KHz

0~20KHz

0~200KHz

Rise Time

0~0.2mS~75μS

0~12μS

0~1μS

Long-term stability

Typical: ±0.1%FS/year

Maximum: ±0.2%FS/year

Operating temperature

Generally -40℃~85℃

Special can be -10℃~250℃

Zero temperature drift

Typical: ±0.02%FS/℃

Maximum: ±0.05%FS/℃

Sensitivity temperature drift

Typical: ±0.02%FS/℃

Maximum: ±0.05%FS/℃

Power supply range

12~36VDC (generally 24VDC)

±15VDC standard switching power supply

Signal output

4~20mA / 1~5 V DC / 0~5V DC

Load Resistance

≤(U-10)/0.02Ω

Shell protection

The cable is IP67 and the connector connection is IP65

Vibration error

≤±0.01%FS (X, Y, Z axis, 200Hz/g)

Interface and shell

Stainless steel 1Cr18Ni9Ti

O-ring

fluororubber

Sensor diaphragm

Stainless steel 316L

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Pressure Transmitter Calibration Equipment

According to the description in “JJG882-2004 Pressure Transmitter Verification Regulations”. A pressure transmitter is an instrument that converts a pressure variable into a standardized output signal that can be transmitted. And there is a given value between its output signal and the pressure variable Continuous function relationship (usually linear function). Mainly used for the measurement and control of industrial engineering pressure parameters. Differential pressure transmitters are often used for flow measurement.

There are two types of pressure transmitters: electric and pneumatic. The standardized output signals of electric motors are mainly 0mA~10mA and 4mA~20mA (or 1V~5V) DC signals.

illustrate:

The two-wire pressure transmitter is a kind of electric type. Calibration should be carried out according to “JJG882-2004 Pressure Transmitter Verification Regulations”. The required equipment is as follows:

  1. One DC 24V power supply;
  2. One mA ammeter;
  3. One voltmeter;
  4. One standard pressure gauge;
  5. One pressure source;
  6. One piston pressure gauge (4 and 5 are optional when this option is available).

At present, the digital pressure calibrator integrates various functions such as DC24V, voltage measurement, current measurement, on-off measurement, etc. The equipment is constantly developing towards intelligence and miniaturization.

For example, you only need to configure the ConST273 intelligent digital pressure calibrator and the ConST100 series pressure pump. You can complete the HART intelligent pressure transmitter, ordinary pressure transmitter, precision pressure gauge, general pressure gauge, pressure controller, and other pressure instruments. Verification work.

Read more about: What Are 0-10V Pressure Transducers?

Pressure Sensor Calibration Certificate

Extended reading: Static pressure vs dynamic pressure vs total pressure

About the Third-Party Testing Company

The qualifications of the testing company are as follows:

More Featured Pressure sensors:

SI-303 Low-Pressure Transducer
Low pressure transducers for air and non-corrosive gases low pressure measurement. 0 ～ 2.5kPa to 0 ～ 30kPa measurable.
SI-350 Sanitary Pressure Transmitter
Sanitary Pressure Transmitter, also called tri clamp pressure transmitter,
is the pressure transducer with the flush diaphragm (flat membrane) as the pressure sensor.
SI-300 Pressure Transducer 4-20mA/Voltage
The 4-20mA/ Voltage Pressure Transducer,
also called pressure transmitter 4-20mA,
is a pressure sensor with4-20ma/Voltage output.
SI-390 Industrial Pressure Transmitter
Pressure transmitters for general industrial applicaitons. -0.1kPa ~ 0 ~ 0.01kPa ~ 100MPa ~150MPa. 0.1% FS, 0.25% FS, 0.5% FS. 4-20mA (2-wire system), 0-5 / 1-5 / 0-10V (3-wire system)
SI-520 Digital Pressure Sensor
Digital Pressure Sensor is particularly suitable for use in computer control systems. RS485 half-duplex working mode.
SI-302 OEM pressure sensor
OEM pressure sensors from Chinese manufacturer. Silicone filled. Protected by stainless steel diaphragm. Suitable for a variety of fluid media.
SI-703 Flush diaphragm pressure sensor
Flush membrane / diaphragm structure, anti-blocking design. Pressure measurement of viscous media.
SI-10 Liquid pressure sensor
Liquid pressure sensor is widely used for pressure measurement of various liquids. Like water or oils. IP68 waterproof.

How Do You Calibrate a Smart Pressure Transmitter?

Pressure Transmitter Calibration

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Cryogenic Pressure Transducers

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Sino-Inst offers over 20 Pressure sensors. A wide variety of  Pressure sensors options are available to you. Such as free samples, paid samples. Sino-Inst is a globally recognized manufacturer of Pressure sensors, located in China.

Of course, according to your requirements, we can also provide Pressure Sensor Calibration Case: Third-party Calibration Certificate.

Sino-Inst sells through a mature distribution network that reaches all 30 countries worldwide. Pressure sensors products are most popular in Europe, Southeast Asia, and Mid East. You can ensure product safety by selecting from certified suppliers. With ISO9001, ISO14001 certification.

Differential Pressure Transmitter Installation Guide

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Differential pressure transmitter installation guide helps you solve the installation problem of DP Transmitters.

Differential pressure transmitter is widely used in industrial differential pressure, liquid level, flow measurement. DP transmitters are often used with capillaries, orifices, 3 way manifolds, etc. 　After purchasing the smart differential pressure transmitter, the most concern is installation and debugging. Sino-Inst will share the Differential Pressure Transmitter Installation Guide with you below.

Sino-Inst offers a variety of  differential pressure transmitters for pressure/level/flow measurement. If you have any questions, please contact our sales engineers.

Request a Quote
DP transmitters

Featured DP Transmitters

Piezoresistive Differential Pressure Transmitter
Piezoresistive Differential Pressure Transmitter utilizes the piezoresistive effect of semiconductor silicon materials. Realize accurate measurement of differential pressure.
Smart Differential Pressure Transmitter
Smart Differential Pressure Transmitter measures industrial differential pressure. Can Works with diaphragm seals, capillary, HART. Outputs standard signals (such as 4 ~ 20mA, 0 ~ 5V).
Flange Mounted Differential Pressure Transmitter
Flange Mounted Differential Pressure Transmitter is also called single flange DP level transmitter. For liquid, gas or vapor pressure measurement.
Extended Diaphragm Seal DP Level Transmitter
Extended Diaphragm Seal DP Transmitter is a level transmitter direct mounted on pipe or tank. The isolation diaphragm is in direct contact with the liquid medium.
Remote Seal Differential Pressure Transmitter
Remote Seal DP Transmitter is often used as a tank level transmitter. The smart pressure transmitter is connected with a stainless steel flange by capillary. The pressure is sensed by a remote transmission device installed on a pipe or container. 
Differential pressure(DP) level transmitter
Differential pressure (DP) level transmitter is a perfect solution for tank level measurement. Flanges, seal diaphragms, capillaries, and DP transmitter are often used to measure liquid levels.

Working principle of differential pressure transmitter:

The two pressures of the measured medium of the pressure transmitter pass into the high and low pressure chambers. Act on the isolation diaphragm on both sides of the delta element (ie the sensitive element). The filling liquid in the spacer and the element is transferred to both sides of the measuring diaphragm. The electrodes on the measuring diaphragm and the insulating plates on both sides each form a capacitor.

When the pressures on both sides are inconsistent, the measurement diaphragm will be displaced. The displacement is proportional to the pressure difference. Therefore, the capacitance on both sides is not equal. Through the oscillation and demodulation link, it is converted into a signal proportional to the pressure. The working principle of pressure transmitter and absolute pressure transmitter is the same as that of differential pressure transmitter. The difference is that the low pressure chamber pressure is atmospheric pressure or vacuum.

The A/D converter converts the current of the demodulator into a digital signal, whose value is used by the microprocessor to determine the input pressure value. The microprocessor controls the work of the transmitter. In addition, it performs sensor linearization. Reset the measurement range. Engineering unit conversion, damping, square extraction, sensor fine-tuning and other operations, as well as diagnosis and digital communication.

The D/A converter fine-tunes the data with the corrected digital signal from the microprocessor. These data can be modified by the transmitter software. The data is stored in the EEPROM, even if the power is off, it is kept intact.
The digital communication line provides a connection interface for the transmitter and external equipment. This circuit detects the digital signal superimposed on the 4-20mA signal and transmits the required information through the loop.

For more about the working principle of differential pressure transmitter, please refer to “Differential Pressure Transmitters”.

You may like: How does a pressure transmitter work?

Installation method of differential pressure transmitter:

  1. Direct pipeline installation. This installation method is simple and uses less materials.
  2. Flange installation. Mainly used in liquid level measurement. Use the static pressure of the liquid to measure the liquid level.
  3. Bracket installation (tube-mounted flat bracket). This type of installation is mostly adopted, which is convenient for installation and maintenance. In the past, the instrument box was used in the open air to protect the intelligent differential pressure transmitter from dust and rain. But the protection of the current smart differential pressure transmitter is very good. The protection grade is IP65, the working environment temperature is -40～+75℃, vibration resistance, dustproof, rainproof, maintenance-free for 5 years.

Extended reading: Smart Differential Pressure Transmitter

Differential Pressure Transmitter Installation Guide

Initial state: all valves are in the closed position

  1. Open the two primary doors on the positive and negative pressure side
  2. Open the balance valve
  3. Wait for the steam in the pressure line and the condensate container to condense
  4. Open the secondary door on the positive pressure side and the drain screw of the positive measurement chamber until the condensate without air is discharged
  5. Close the drain screw of the positive measurement chamber
  6. Turn on the drain screw of the negative measurement chamber until the condensate without air is discharged
  7. Close the secondary door on the positive pressure side
  8. Open the secondary door on the negative pressure side until the condensate that does not contain air is discharged from the drain screw of the negative measurement chamber
  9. Close the drain screw of the negative measurement chamber
  10. Close the negative secondary door
  11. Open the secondary door on the positive pressure side again
  12. Check for leakage and check the zero point of the instrument
  13. Close the balance gate
  14. Fully open the secondary door on the positive and negative pressure side.
Extended Reading: Advantages and disadvantages of differential pressure flow meter

Reason: drain the pipeline and the air in the measurement room to reduce errors
Protect the transmitter so that the differential pressure on the positive and negative pressure sides is appropriate.
The input should be to open the positive pressure side first (slowly), then close the balance door, then open the negative pressure side, and finally ensure that the positive and negative sides are fully open and the balance door is closed.

Because if you open both the positive and negative sides, the pressure on the positive side is greater than the negative side, because the balance door is open at that time. In that way, the condensate on the positive pressure side will flow back into the negative pressure pipe, and the pipe will have steam and generate heat, which will damage the transmitter.

Read more about: What is industrial pressure transmitter?

Operating Regulations of Differential Pressure Transmitter

  1. The range adjustment and check accuracy of the differential pressure transmitter should be carried out behind the indoor panel using a handheld communicator, and must not be operated on site with power.
  2. After adjusting the range, the differential pressure transmitter should be calibrated. The process is as follows:
    Open the balance valve, first close the low-pressure side inlet valve, then close the high-pressure side inlet valve, and open the high-low pressure side exhaust valve. At this time, the computer displays zero.
    Correctly connect the process tester, differential pressure module, and hand-operated pump to the exhaust hole of the high-pressure end, and close the balance valve.
    Adjust the pressure to half of the range and full range respectively. At the same time, observe whether the data change at this point is consistent with the range on the indoor computer.
    Remove the calibration instrument, close the exhaust hole, open the balance valve, open the high-pressure side inlet valve, open the low-pressure side inlet valve, and slowly close the balance valve.
  3. If the differential pressure transmitter must be disassembled, the following requirements should be strictly followed.
    Turn off the power of the differential pressure transmitter and confirm that it is correct.
    Open the balance valve, first close the low pressure side inlet valve, then close the high pressure side inlet valve, and open the high and low pressure side exhaust valve.
    Close the intake valve on the orifice side.
    Open the differential pressure transmitter wiring terminal, remove the meter wiring, write down the wiring sequence, and pull out the meter wiring.
    Remove the transmitter.
    Wrap the plastic bag of the pressure tapping hole tube with the head of the explosion-proof hose facing down to prevent water from entering.

In short, I hope everyone will take a look at the installation diagram of the smart differential pressure transmitter before putting it into operation. This way, I know it. The Differential Pressure Transmitter Installation Guide introduced in this article is suitable for smart differential pressure transmitters produced in China. The same applies to brands such as Rosemount.

If you have any questions about differential pressure transmitters, please contact our sales engineers.

Extended reading: How to calibrate HART pressure transmitters

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Read more What is a diaphragm seal?

Sino-Inst is a Differential pressure transmitter manufacturer. We provide more than 20 kinds of differential pressure transmitters. Including flange differential pressure level transmitter. Capillary diaphragm differential pressure transmitter, etc. Differential pressure transmitters are also used in the measurement of flow, liquid level, density, etc.

Differential Pressure Transmitter Installation Guide is a simple guide we provide you. If you encounter problems when installing the differential pressure transmitter, please feel free to contact our engineers.

Use Differential Pressure Transmitter to Measure Liquid Level

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Differential Pressure Level transmitter for Continuous tank level measurement.

A liquid level measurement solution that prevents the measured medium from directly acting on the transmitter.itle

In the chemical production, the medium often encounters problems such as impurities, crystal particles or agglomeration. It is easy to block the connecting pipeline. At this time, a flange-type differential pressure transmitter is required.

Silicone oil is filled in the closed system composed of the bellows, capillary tube and measuring chamber as the pressure transmission medium. The measured medium does not enter the capillary tube and the transmitter to avoid blockage.

Flange Mounted Differential Pressure Transmitter
Extended Diaphragm Seal DP Level Transmitter
Remote Seal Differential Pressure Transmitter
Differential pressure(DP) level transmitter

Differential Pressure Level transmitters are divided into single flange type and double flange type according to their structure.

Only a flange between the container and the transmitter is called a single flange differential pressure transmitter.

As for the closed container whose upper end is isolated from the atmosphere, the upper space and atmospheric pressure are mostly different. Two flanges must be used to guide the liquid and gas phase pressure to the differential pressure transmitter. This is the double flange differential pressure transmitter.

Read more What is a diaphragm seal?

Differential Pressure Level transmitter for open containers

Open tank level measurement means that the tank is open to the atmosphere. Any change in atmospheric pressure will affect the process fluid pressure in the tank. In this liquid level measurement application, the low pressure side of the transmitter can measure the atmospheric pressure. This eliminates the influence of atmospheric pressure on the tank liquid level. The high-pressure side of the transmitter is connected to the tank. Therefore, the actual liquid level in the tank can be measured.

A single flange is used to measure the liquid level of an open tank.

Differential pressure range calculation method: Need to measure the height of the liquid level (unit: m) × acceleration of gravity (9.8) × measured medium density (unit: g/cm3) differential pressure range (unit: KPa).

The selection must know the measurement medium, measuring range, medium temperature, the size and pressure rating of the process connection flange, and the flange standard.

Image Source: https://www.yokogawa.com/in/library/resources/media-publications/how-to-avoid-temperature-effects-in-differential-pressure-level-measurements/

Extended Reading: Differential Pressure (DP) Flow Meters Technology

Differential Pressure Level transmitter for closed containers

For airtight containers, the inside is isolated from the atmosphere. When the process fluid fills or empties the tank, the pressure in the tank may change from positive pressure to vacuum. This change in tank pressure will directly affect the measured liquid level unless it is compensated for. This can be done by connecting the low-side pipe of the differential pressure transmitter to the top of the tank. Therefore, when measuring the liquid level of a closed tank, a differential pressure transmitter must be used.

Double flanges are used to measure the liquid level of a closed tank.

The calculation method of the differential pressure range: the height of the liquid level to be measured (unit: m) × acceleration of gravity (9.8) × (the density of the measured medium-the density of the capillary filling liquid) (unit: g/cm3) = differential pressure range (unit: KPa).

The selection must know the measurement medium, measuring range, medium temperature, pressure, capillary length, the size and pressure rating of the process connection flange and the flange standard

If you need to measure river water level, open channel level, etc. The Ultrasonic Liquid Level Sensor can be used for non-contact continuous level monitoring.

Read more about: 7 Level Senors for Tank Level Measurement

Differential pressure level transmitter working principle

When using Differential pressure (DP) level transmitter to measure the liquid level as shown in the figure below.
The measured liquid density in the figure is ρ.
The working medium density in the capillary of the double flange differential pressure transmitter is ρ0.
The measuring range of the measured liquid level is H.
The center distance of the sampling tube of the measured liquid level is h.
It can be seen from the figure that the maximum measurement range of the liquid level △ P = P + —P- = H × ρ × g-h × ρ0 × g.

It can be seen from the formula that the dual-flange differential pressure transmitter should perform negative migration. The migration amount S is h × ρ0 × g. And the installation position of the double flange differential pressure transmitter has no effect on the migration amount and the measurement result.

Extended reading: Hydrostatic Level Measurement

The dual-flange differential pressure transmitter requires negative migration.

When the measured liquid level is 0, the pressure difference between the positive and negative measurement chambers of the remote differential pressure transmitter is the largest. The output current of the double flange differential pressure transmitter is 4mA.

As the measured liquid level rises, the pressure difference between the positive and negative measurement chambers of the transmitter gradually decreases.

When the measured liquid level rises to the highest Hmax. The pressure difference between the positive and negative measurement chambers of the transmitter is the smallest. The output current of the double flange differential pressure transmitter is 20mA.

Extended Reading: Procurement Guide for Ultrasonic liquid level sensors

You may like:

Sino-Inst offers overs 100 DP transmitters for liquid level, pressure, flow, temperature measurement. Differential pressure (dp) level transmitters suit to measeure water and other liquid level.

A wide variety of DP level transmitters are available to you. Such as SMT3151LT Differential pressure level transmitter.

You can also choose from liquid flow meter and pressure transmitters, not specified. We are differential pressure level transmitter suppliers, located in China. The top supplying country is China(Mainland), which supply 100% of DP transmiters respectively.

MEMS Pressure Sensors

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MEMS pressure sensors are pressure sensors manufactured using MEMS technology. MEMS pressure sensors include silicon piezoresistive pressure sensors and silicon capacitive pressure sensors.

MEMS pressure sensors are the earliest developed miniature sensors with a large market share. MEMS pressure sensors can be divided into piezoresistive and capacitive types. Both are micromechanical electronic sensors generated on silicon chips. MEMS pressure sensors can use high-precision, low-cost mass production with integrated circuit-like design techniques and manufacturing processes. This makes pressure control simple, easy to use, and intelligent. Compared with traditional mechanical quantity sensors, the size of MEMS pressure sensors is smaller, and the largest is no more than one centimeter. Compared with traditional “mechanical” manufacturing technology, its cost performance is greatly improved.

Sino-Inst offers a variety of MEMS pressure senors for industrial pressure measurement. If you have any questions, please contact our sales engineers.

CONTACT US
Pressure Sensors
Industrial Pressure Sensor for OEM applications
High Temperature Pressure Sensor
Combined Pressure and Temperature Sensor-Dual function
High Pressure Sensor
Gauge Pressure Transmitter/Transducer
Hydrostatic Pressure Sensor/Transmitter
Piezoresistive Differential Pressure Transmitter
Differential pressure(DP) level transmitter

Features of MEMS Pressure Sensors

  • Single crystal silicon sensor using German MEMS technology
  • Integrated sensor design using patented technology
  • Two-wire system. 4 ~ 20mA analog output. HART® digital communication or four-wire system. RS485 output (MODBUS protocol)

Read more about: What is a pressure sensor and how it works? 

Specifications of MEMS Pressure Sensors

RangeMinimum rangeDPRange and sensor limit (kPa)Minimum rangeGPRange and sensor limit (kPa)Minimum rangeAPRange and sensor limit (kPa)
Code（kPa）Upper range (URL)Lower limit of range (URL)（kPa）Upper range (URL)Lower limit of range (URL)（kPa）Upper range (URL)Lower limit of range (URL)
10.11-1//////
20.25-5//////
30.220-200.220-20///
40.550-500.550-500.5500
52200-2002200-10022000
65500-5005500-100///
7202000-500202000-1002020000
810010000-50010010000-100100100000
9///40040000-100///
Measuring range of MEMS pressure sensor
  1. Sensor type: German MEMS technology single crystal silicon sensor
  2. Range ratio: 100: 01: 00
  3. Accuracy grade: 0.075, 0.1, 0.2
  4. Stability: 36 months error is ± 0.2% of maximum range
  5. Temperature effect:
    1. “0.075 level: zero point or range error is ± 0.15% / 28 ℃ of maximum range
    2. 0.1 level: Zero point or range error is ± 0.2% / 28 ℃ of maximum range
    3. Level 0.2: Zero point or range error is ± 0.25% of maximum range / 28 ℃ “
  6. Output signal: “Two-wire system, 4 ～ 20mA DC, HAR T® protocol digital signal. Or four-wire system, RS485 output (MODBU S protocol)”
  7. Metrology certification: CMC
  8. Explosion-proof certification: “Explosion-proof type: Exd IIC T6 Gb
                 Intrinsically safe type: Exia IIC T6 Ga or Exib IIC T4 Gb “
  9. Protection grade: IP67

You may like: Explosion Proof Pressure Transmitter for Hazardous locations

What does MEMS mean?

MEMS is the abbreviation of Micro-Electro-Mechanical Systems. MEMS is the name of the United States. In Japan, it is called micromachine. In Europe, it is called microsystem. MEMS refers to mass production, which integrates micro-mechanisms, micro-sensors, micro-actuators, signal processing and control circuits, and interfaces. , Communication and power supply are equal to a micro device or system. MEMS is developed with the development of 1653 technology for semiconductor integrated circuit micromachining and internal ultra-precision mechanical processing technology. Currently MEMS processing technology is also widely used in microfluidic chips and synthetic biology. Chip integration of the technical process of the actual volume laboratory.

What is a MEMS pressure sensor?

MEMS pressure sensor is a pressure sensor manufactured by MEMS technology.
MEMS pressure sensors are the earliest developed miniature sensors with a large market share. The current application field has been greatly expanded, far beyond the traditional applications in industrial transmitters and other fields. Generally, MEMS pressure sensors are made by bulk silicon processing technology, and some are made by surface silicon processing technology. MEMS pressure sensors can be divided into piezoresistive and capacitive. Similar to other sensors, the MEMS pressure sensor converts the pressure into an electrical signal output during operation.

Extended Reading: Digital Pressure Sensor-RS485

Piezoresistive MEMS pressure sensor

The piezoresistive MEMS pressure sensor uses a high-precision semiconductor resistance strain gauge to form a Wheatstone bridge as a force-electric conversion measurement circuit. It has high measurement accuracy, low power consumption, and extremely low cost.

Capacitive MEMS pressure sensor

Capacitive pressure sensors use MEMS technology to produce a diaphragm grid on the silicon wafer. The upper and lower diaphragms become a group of capacitive pressure sensors. The upper diaphragm is displaced downward by pressure and changes the upper and lower diaphragms. The spacing of the grids also changes the capacitance between the plates, that is, △ pressure = △ capacitance

Read more about: Capacitive pressure transducer

How does a MEMS pressure sensor work?

The MEMS piezoresistive pressure sensor uses a circular stress cup silicon film inner wall fixed around the periphery. MEMS technology is used to directly engrave four high-precision semiconductor strain gauges on the surface with the highest stress. Make up the Wheatstone measuring bridge. As a force-electricity conversion measurement circuit. The physical quantity of pressure is directly converted into electricity. The measurement accuracy can reach 0.01% ～ 0.03% FS.

You may like: How does a pressure transmitter work?

The MEMS capacitive pressure sensor uses MEMS technology to produce a diaphragm grid on the silicon chip. The two upper and lower diaphragms become a group of capacitive pressure sensors. The upper MEMS capacitive pressure sensors use MEMS technology to create a grid-like shape on a silicon wafer. The two upper and lower transverse barriers become a group of capacitive pressure sensors. The upper diaphragm is displaced downward by pressure. Changed the spacing between the upper and lower two horizontal barriers. It also changes the size of the capacitance between the boards.

Video on How MEMS Pressure Sensor Operation:

Video source: https://www.youtube.com/watch?v=juf4d3sgOJw

Applications of MEMS Pressure Sensors

  1. Applied in the automotive industry
    A new application of MEMS pressure sensors in automobiles is the transmission system pressure sensing. It is usually used in automatic devices. But it is also used in new dual clutch transmission systems. German manufacturers have introduced a MEMS solution that uses oil to protect the silicon film so that it can withstand pressures up to 70 bar. Bosch also brought huge changes to MEMS pressure sensors a few years ago. At that time, porous silicon was used to bring highly reliable MEMS devices. These devices have been used in current side airbag applications.
  2. Applied to the medical market
    The pressure sensor mainly serves as a disposable low-cost catheter for surgical operations. But they are also used in expensive equipment. Sensing pressure and differential flow in continuous positive airway pressure (CPAC) machines.
  3. Applied in the industrial field
    The main applications of MEMS pressure sensors include heating, ventilation and air conditioning (HVAC), water level measurement, and various industrial process and control applications. For example, in addition to accurate altitude and barometric pressure measurements, aircraft use sensors to monitor engines, flaps, and other components.

Extended reading: What is a pressure sensor?

Frequently
Asked
Questions

Help Center

Depending on the type of pressure to be measured:
Pressure transmitter types include gauge pressure, absolute pressure, and differential pressure. Gauge pressure refers to the pressure that is less than or greater than atmospheric pressure based on the atmosphere. Absolute pressure refers to the absolute zero pressure as the reference and is higher than the absolute pressure. Differential pressure refers to the difference between two pressures.
According to the working principle of the pressure transmitter:
Strain Gauge Pressure Transducers
Capacitance Pressure Transducers
Potentiometric Pressure Transducers
Resonant Wire Pressure Transducers

First of all, the parameters that must be seen when purchasing a pressure transmitter are:
Pressure range. Range. Measurement medium. Installation method-threaded flange clamps, etc. Installation dimensions. Temperature. Whether with display. Whether with HART protocol. Output type. Current output or voltage output. Explosion-proof level, protection level. Accessories. Mounting bracket.
The above parameters will affect the price of the pressure transmitter.
Sino-Inst, as the manufacturer of pressure transmitter, offer you with the best price.

At present, there are mainly two types of MEMS pressure sensors: silicon piezoresistive pressure sensors and silicon capacitive pressure sensors. Both of these are micro-mechanical electronic sensors produced on silicon chips.

The first type: silicon piezoresistive pressure sensor

The silicon piezoresistive pressure sensor uses a Wheatstone bridge composed of high-precision semiconductor resistance strain gauges as the measurement circuit for electromechanical conversion. It has the advantages of high measurement accuracy, low power consumption, and low cost. The output of the piezoresistive sensor in the wheatstone bridge is zero. If there is no pressure change, there is almost no power consumption.

The MEMS silicon piezoresistive pressure sensor is the inner wall of a silicon membrane with a circular stress cup fixed around it. Using MEMS technology, four high-precision semiconductor strain gauges are directly engraved on the place with the largest surface stress to form a Wheatstone measurement bridge. As an electromechanical conversion measurement circuit, it directly converts the physical quantity of pressure into electrical energy. Its measurement accuracy can reach 0.01-0.03%FS.

The second type: capacitive pressure sensor

The capacitive pressure sensor uses MEMS technology to make a horizontal grid shape on a silicon wafer. The upper and lower horizontal grids form a set of capacitive pressure sensors. The upper horizontal grid moves downward under pressure to change the distance between the upper and lower horizontal grids and the capacitance between the plates, that is Pressure = Capacitance.

MEMS pressure sensors can adopt the design technology and manufacturing process similar to integrated circuits, so as to carry out high-precision, low-cost mass production, and have a wide range of applications in ventilators, automobiles, earphones, mobile phones and other fields.

More Pressure Measurement Solutions

Flow Pressure Transducers for Fluid Pipelines

Flow Pressure Transducers are measurements of fluid pressure within a pipeline. When fluid flows through a pipe, pressure acts on the pipe wall. The medium in the pipeline can be…

High Accuracy Pressure Transducers

High Accuracy Pressure Transducers are also called high precision pressure transducers or high accuracy pressure sensors. Sino-Inst manufactures various types of High Accuracy Pressure Transducers. From the perspective of accuracy,…

Sino-Inst offers over 20 MEMS Pressure Sensors. About 50% of these are 4-20ma Low-Pressure Transducers, 40% are Differential Pressure Gauge, and 20% are Diaphragm Seal Pressure transmitters, 20% are 4-20ma differential pressure transmitters.

A wide variety of MEMS Pressure Sensors options are available to you, such as free samples, paid samples. Sino-Inst is a globally recognized supplier and manufacturer of Pressure Transducers, located in China.

You can ensure product safety by selecting from certified suppliers, with ISO9001, ISO14001 certification.

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Application Analysis of Intelligent Pressure Transmitter

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Intelligent Pressure Transmitter is also called smart pressure transmitter.

Current intelligent pressure transmitters are generally hybrid intelligent pressure transmitters that have both digital and analog signals. Communication with DCS is mainly based on passing 4-20mA analog signals. Then superimpose digital signals on them for remote Set the zero point, range, and calibration, configuration, and diagnostics of the transmitter. It is only designed to be compatible with the existing DCS. Smart pressure transmitter is a transition product of true all-digital smart pressure transmitter (such as field bus type intelligent pressure transmitter).

As far as the composition structure of intelligent pressure transmitters widely used in the market is concerned, it mainly includes devices such as microprocessors, sensors, digital-to-analog converters, and memories. Different devices play different automatic control functions. The sensors are mainly aimed at The measured signal is detected. There are some differences in the materials designed in the specific application. As the core part of the entire device, the microprocessor is mainly used for comprehensive analysis and calculation of the relevant data collected by the device. Unit conversion, fault diagnosis, range adjustment, function calculation, etc. are performed for the detection signal. The function of the memory is to implement the configuration for the relevant data and programs in the microprocessor. At present, most of the memory used by people have the function of rewriting and adjusting. Related converters are mainly responsible for the interchange of digital signals related to analog signal machines. Smart pressure transmitters can communicate with DCS by outputting a series of digital signals. A reserve power supply is also set in the transmitter, which can prevent the memory data from being lost in the event of a power failure. According to the different types of sensors used in smart pressure transmitters, the transmitters can also be classified into capacitive, diffused silicon strain, and diffused silicon resonant types.

Featured Smart Pressure Transmitters

Diffused silicon Gauge Pressure Transmitter
A gauge pressure (GP) transmitter compares a process pressure against local ambient air pressure. Gauge pressure transmitters have ports to sample the ambient air pressure in real-time.
High-Temperature Pressure Transmitter
High-temperature pressure transmitters with a 4-20mA output.
which has a temperature capability of over 700 °C and is not pyroelectric.
Explosion-proof Pressure Transmitter
Explosion-proof Pressure transmitter, or explosion-proof pressure transducer, with the explosion-proof enclosure.
For applications in hazardous areas.
Diaphragm Seal Pressure Transmitter
When the process medium should not come into contact with the pressured parts of the measuring instrument. Diaphragm sealed pressure transmitters are used for pressure measurement.
Hygienic / Sanitary Pressure Transmitter
Also called Hygienic pressure Transmitters, or tri clamp pressure transmitter. Sanitary pressure Transmitters is used to food &beverage or pharmaceutical application.
Capacitive Gauge Pressure Transmitter
Gauge pressure (GP) transmitters compare process pressure with local ambient air pressure. Gauge pressure transmitters have ports for real-time sampling of ambient air pressure.
Absolute Pressure Transmitter
Absolute pressure transmitter with 4-20mA output for measuring pressure with absolute type reference. Absolute pressure (AP) transmitter is a measure of the ideal (complete) vacuum pressure.
Hydrostatic pressure transmitter
Hydrostatic pressure transmitter is used for fluid hydrostatic pressure measurement. With working static pressure up to 32Mpa, for liquid, gas or steam .

Function of Smart Pressure Transmitters

  • Type: Pressure- Differential(DPIT), Gauge/ Absolute(PIT), Level(LIT), High Static Pressure, Flow Pressure(FIT)
  • Certificate: SIL2 (TUV, FMEDA), Ex d, Ex ia, FM, ATEX, TR CU(EAC), INMETRO, CE, Rohs, BV, LR, KR, DNV, ABS, KCs, IP66/67, NEMA 4X
  • Feature: 4 to 20mA, HART, Loop Powered
  • Accuracy: ± 0.075% (option ± 0.04%) of CS* 3 lines LCD display, Self Diagnostic Function, External Buttons, DAC, Zero Trim, Eng mode
  • Application: Pressure, Flow, Level measurement for Oil & Gas, Liquid, Water, Maine & offshore, Vessel, Power, Chemical Plants and Refinery

More about: Absolute Pressure Vs Gauge Pressure.

Hydrostatic pressure for level measurement:

SI-151 Hydrostatic Level Sensor
SI-PCM260 Deep Well Water Level Sensor
SMT3151TR Hydrostatic level transmitter-Rod Type

Main Features of Smart Pressure Transmitters

Compared with conventional analog transmitters, smart pressure transmitters have many characteristics. Take Rostman smart pressure transmitters as an example. The characteristics of this pressure transmitter are mainly concentrated on the following points:

1. Wide range and large range ratio

Intelligent pressure transmitters generally have a wide measuring range. The measuring range ratio is large, from 30: 1 to 100: 1, and some even reach 400: 1. The measuring range ratio of the transmitter refers to the maximum measurement range (URV) and the minimum measurement Range (LRV) ratio. Because the intelligent pressure transmitter has a wide measuring range, compared with conventional analog pressure transmitters, the biggest advantage is that it can reduce the inventory. At the same time, according to the process requirements, the measuring range can be changed at any time without following the meter change, without having to change the meter. Don’t worry about exceeding the range.

2.Simple and convenient maintenance

The handheld communicator can be used to communicate with the intelligent pressure transmitter at the terminal of the field transmitter or at the terminal in the control room of the main control room. In this way, the instrument maintenance personnel can perform range modification, parameter setting, and instrument maintenance on the transmitter in a relatively safe and relatively good control room.

3.With high and low voltage side conversion function

Intelligent pressure transmitters generally have high- and low-pressure side conversion functions of the sensor, and the internal parameters can be adjusted with a handheld communicator. I encountered such a problem in production. Because the meter has been running for many years, the pressure guiding tube connected to the transmitter needs to be replaced due to leakage. When the meter is put into operation after replacement, it is found that the positive and negative phase pressure guiding tubes are reversed (because the pressure guiding tube is long , And there is a heat tracing tube together, the positive and negative phases are easily reversed). The intelligent pressure transmitter has high and low pressure side conversion functions, as long as the parameter items in the table are changed from NORMOAL (high pressure on the right side, low pressure on the left side) to REVERSE (low pressure on the right side, high pressure on the left side). After reconfiguring the table, Everything works fine, saving time and effort.

4. With fixed output function

This function is more convenient to use in the following situations: When the transmitter fails, in order to ensure the safety of production equipment and personnel, or to ensure product quality, the transmitter output needs to be a fixed value. After the annual overhaul, due to the meter All links in the control circuit have been overhauled. The entire circuit needs to be co-calibrated before driving. At this time, the fixed output function of the intelligent transmitter can be used by the hand programmer. Generally, any value between 3.8-21.6mA can be set, and the whole circuit where it is located is cascaded.

In addition, the intelligent pressure transmitter has the characteristics of high accuracy, good stability and high reliability.

Extended Reading: Selection of pressure transmitter

Application Analysis of Intelligent Pressure Transmitter

Used as a reminder of impulse pipeline problems

In general, the intelligent pressure transmitter is connected to the process through a small-diameter pipe, and this management is the impulse pipeline. In some applications, such impulse lines may be blocked by materials or frozen due to cold weather. These blockages may cause difficulties in transmitting pressure signals. In this case, the use of conventional pressure transmitters cannot be used to understand this clogging problem. The main reason is that in the case of a blockage problem, there is a certain difference between the signal indicated by the transmitter and the signal provided before the blockage occurred. It must be ensured that the output of the transmitter does not change with the actual flow rate change before it can be found The problem. It has been found in practice that if one or two impulse lines are blocked during some flow measurement processes, the standard deviation at a specific flow will change greatly. The intelligent pressure transmitter can effectively detect such changes. In this way, the blocking position of the impulse pipeline can be controlled in time, which facilitates fault finding and avoids increasing problems.

For flame instability detection in refining furnaces

In many chemical fields, refining furnaces are important equipment. Incineration of different chemical production waste gases is required. Because many BTUs coexist, the flame stability is not very good, which is also an important sign that the refining furnace is out. The application of intelligent pressure transmitter can measure the noise of the fire control pressure in the room. The transmitter can be used to detect the flame stability. The general measurement accuracy is relatively high, and it can detect the abnormal signal in the refining furnace. . Convenient staff to correct equipment problems in time to avoid flameout.At present, smart pressure transmitters are also used in related fields to a certain extent, which belongs to the category of precision instruments. In many fields of application, smart pressure transmitters can accurately detect related signals and data information, find abnormalities in time, and facilitate Find and repair the corresponding faults. It is helpful to reduce system failures and improve system operation efficiency.

Q&A

What is smart pressure transmitter?

Digital smart pressure transmitter is pressure sensor with a 12-bit or higher microprocessor. Smart pressure transmitters are high performance microprocessor-based transmitters with flexibility. Pressure calibration and output, automatic compensation.
Smart pressure transmitter also called intelligent pressure transmitter.
The intelligent pressure transmitter consists of two parts: a smart sensor and a smart electronic board.
The smart sensor part includes: a capacitive sensor. A measuring diaphragm detection circuit. A temperature sensor, and a temperature compensation circuit.
The smart electronic board includes: a microcomputer controller. And the peripheral circuit, complete the pressure signal to 4 ~ 20mA dc conversion.
Smart Pressure Transmitter is used to measure the pressure of liquid, gas or steam. And then convert the pressure signal into 4 ～ 20mA DC signal output. The intelligent pressure transmitter produced by Sino-Inst can communicate with the HART communicator. It is widely used in weakly corrosive liquids in industrial pipelines, Gas and steam measurement and control systems.
Extended reading: How to calibrate HART pressure transmitters

What is the principle of pressure transmitter?

Like other transmitters, a pressure transmitter consists of electronics connected to a sensor. We can find transmitters with many types of pressure sensors on the market – capacitive, piezoelectric, resonant silicon, and more.
So pressure applied to capacitive cells will produce a change in the capacitance of the sensor. This change will affect the oscillator frequency, and the pressure transmitter will detect this change. Then the transmitter translates this data into a standard output signal that we can read.
Using a local setup or a handheld, you can adjust the transmitter, changing information like the unit, measuring range, and output.
More: How does a pressure transmitter work

How do you calibrate a smart transmitter?

To perform the test:
1. Isolate the transmitter from the process being measure and its loop wiring. If measuring the mA signal across the transmitter test diode leave the wires intact, but note this method does not give the best mA measurement accuracy.
2. Connect the mA measurement jacks of the 754 to the transmitter.
3. Connect the pressure module cable to the 754 and connect the transmitter test hose from the hand pump to the transmitter.
4. Press the HART button on the calibrator to see the configuration of the transmitter.
5. Press HART again and the calibrator will offer the correct measure/source combination for the test. If documenting the calibration press As-Found, input the test tolerance and follow the prompts. If the measured mA signal at the test points is found within tolerance the test is complete. If not, adjustment is required.
6. Select, adjust, and trim the pressure zero, mA output signal and input sensor.
7. After adjustment select As-Left, document the condition of the transmitter and after adjustment and if the test passes, it is complete.
More: Pressure Transmitter Calibration

How do you calibrate a pressure transmitter with HART Communicator PDF?

The basic procedure for calibration
1. Isolate the Pressure Transmitter from the Process.
2. Slowly open the vent plug and the vent valve to release the pressure.
3. Connect the multimeter with the transmitter and ensure that output is 4ma when 0 pressures are applied.
4. Connect the handheld test pump (pressure source) to the transmitter.
5. Ensure there is no leak.
6. Apply pressure range at 0%, 25%, 50%, 75%, 100% and check there is any error.
7. If there is any error calibration should be done.
Extended reading: Smart Differential Pressure Transmitter

Differential Pressure Flow Meters

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Differential Pressure (DP) Flow Meters Technology –
Reliable Flow Solutions Across Many Applications

Differential Pressure Flow meters, also known as DP flow meters. Differential Pressure (DP) flow meters introduce a constriction in the pipe, that creates a pressure drop across the flow meter.

The calculation of fluid flow rate, by reading the pressure loss across a pipe restriction, is the most used flow measurement technique in industrial applications.

Differential pressure flow meters are suitable for water flow measurement, oil, steam or gas flow measurement.

According to different flow senor structures, we have:

  • Orifice Plate Flowmeters;
  • Venturi Flowmeters;
  • Nozzle Flowmeters;
  • Wedge Flowmeters;
  • Annubar Flowmeter

And more.

RFQ NOW

What is a differential pressure flow meter?

You can take this as the definition of the differential pressure flow meter.

Differential pressure flow meters, also known as DP flowmeters, create a cross-sectional change in the flow tube, which causes the velocity of the flowing fluid to change.

A change in velocity occurs whenever there is a change in flow cross-section; ie, With a decrease in velocity, an increase in pressure occurs.

Differential pressure flow meters can be used as liquid flowmeters or gas flowmeters; however, a single flow meter may not be configured to measure both liquid and gas phases.

Differential pressure (also known as throttling) Flow meters, are based on the throttling principle of fluid flow. It is one of the most mature and most commonly used methods for measuring flow in production. It is usually composed of a throttling device, which capable of converting the measured flow into a differential pressure signal, and a differential pressure gauge, and a display instrument, capable of converting the differential pressure into a corresponding flow value.

In the unit combination meter, the differential pressure signal generated by the throttling device, is often converted to a corresponding standard signal (electrical or pneumatic), by a differential pressure transmitter for display, recording or control.

The differential pressure flow meter is composed of a primary device (detection member), and a secondary device (a differential pressure converter and a flow display instrument).

Types of flow meter

The differential pressure flow meter is usually classified in the form of a test piece, such as an orifice flowmeter, a venturi flowmeter, a constant velocity tube flowmeter, a pitot tube principle-Pitoba flowmeter, and so on.

The secondary device is a variety of mechanical, electronic, electromechanical integrated differential pressure gauges, differential pressure transmitters and flows display instruments.

It has developed into a large-scale instrument with a high degree of categorization (series, generalization, and standardization) and a wide variety of specifications.

It can measure flow parameters as well as other parameters (such as pressure, level, density, etc.).

You may like the pressure level transmitter.

How does a differential pressure flow meter work?

Differential pressure flow meters use Bernoulli’s equation, to measure the flow of fluid in a pipe.

Differential pressure flow meters introduce a constriction in the pipe, that creates a pressure drop across the flowmeter.

When the flow increases, more pressure drop is created. Impulse piping routes the upstream and downstream pressures of the flowmeter to the transmitter, that measures the differential pressure to determine the fluid flow.

This technology accounts for about 21% of the world market for flow meters.

Bernoulli’s equation states that the pressure drop across the constriction is proportional to the square of the flow rate. Using this relationship, 10 percent of full-scale flow produces only 1 percent of the full-scale differential pressure.

At 10 percent of full-scale flow, the differential pressure flowmeter accuracy is dependent upon the transmitter, being accurate over a 100:1 range of differential pressure.

Differential pressure transmitter accuracy is typically degraded, at low differential pressures in its range, so flowmeter accuracy can be similarly degraded.

Therefore, this non-linear relationship can have a detrimental effect on the accuracy, and turn down of differential pressure flow meters.

Remember that of interest is the accuracy of the flow measurement system — not the accuracy of the differential pressure transmitter.

Different geometries are used for different measurements, including the orifice plate, flow nozzle, laminar flow element, low-loss flow tube, segmental wedge, V-cone, and Venturi tube.

Read more about: Shop 101: Key Factors In Selecting A Pipe Flow Meter

Differential pressure flow meter formula:

where

  • points 1 and 2 lie on a streamline,
  • the fluid has constant density,
  • the flow is steady,
  • and there is no friction.

Although these restrictions sound severe, the Bernoulli equation is very useful, partly because it is very simple to use. And partly because it can give great insight into the balance between pressure, velocity, and elevation.

To learn more about DP Flow:

Extended reading: Smart Differential Pressure Transmitter

Advantages and disadvantages of differential pressure flow meter

The upside of this technology is low cost, multiple versions can be optimized for different fluids and goals, are approved for custody transfer (though it is being used less and less for this). It is a well-understood way to measure flow. And it can be paired up with temperature/pressure sensors, to provide mass flow for steam and other gasses.

Negatives are that rangeability is not good due to a non-linear differential pressure signal (laminar flow elements excepted), accuracy is not the best and can deteriorate with wear and clogging.

Advantages and disadvantages of throttling differential pressure flow meter (orifice flowmeter)

Advantages:    

1) The standard orifice plate structure of the throttle piece is easy to copy, simple, firm, stable and reliable in performance, long in service life and low in price;    

2) The throttling application range is extremely wide. All single-phase fluids, including liquid, gas, and steam, can be measured. Some mixed-phase flows, such as gas-solid, gas-liquid, liquid-solid, etc. can also be applied. General production processes and pipe diameters, The working condition (pressure, temperature) has products;    

3) All accessories can be used by all manufacturers if it is an international standard and can be used without calibration.

Disadvantages:    

1) The repeatability and accuracy of the measurement are medium levels;    

2) The range is narrow because the meter signal and the flow rate are squared, the general range can only reach 3:1 ~ 5:1;    

3) The requirements for on-site installation conditions are relatively high. If a long straight pipe section is required, it is difficult to meet;    

4) The pressure piping is a weak link, which is prone to leakage, blockage, freezing and signal distortion;    

5) The pressure loss is large.

Extended reading: Integral DP Flow Meter|Gas, liquid, steam|Compact structure

What is the relationship between flow and differential pressure?

Differential pressure use Bernoulli’s equation to measure the flow of fluid in a pipe.

Differential pressure flow meters introduce a constriction in the pipe, that creates a pressure drop across the flowmeter.

When the flow increases, more pressure drop is created.

y+P(x)y =Q(x)y^n (equation)

is called a Bernoulli differential equation where n is any real number.

The graph below shows the resulting pressure drop for water at 60 F, over a range of flow rates for a 100-foot long pipe, for both 4 inches and 6-inch schedule 40 piping.

the relationship between flow and differential pressure

If you need, you can learn more about Flow Rate And Pressure Relationship.

How to Select a Flow Meter?

The basis of good flow meter selection is a clear understanding of the requirements of the particular application.

Therefore, time should be invested in fully evaluating the nature of the process fluid and of the overall installation.

  1. What is the fluid being measured by the flow meter(s) (air, water, etc…)?
  2. Do you require rate measurement and/or totalization from the flow meter?
  3. If the liquid is not water, what viscosity is the liquid?
  4. Is the fluid clean?
  5. Do you require a local display on the flow meter or do you need an electronic signal output?
  6. What are the minimum and maximum flow rate for the flow meter?
  7. What are the minimum and maximum process pressure?
  8. What are the minimum and maximum process temperature?
  9. Is the fluid chemically compatible with the flow meter wetted parts?
  10. If this is a process application, what is the size of the pipe?

Types of Differential Pressure Flowmeters

Flat metal plate with an opening in the plate installed perpendicular to the flowing stream in a circular pipe.

As the flowing fluid passes through the orifice, the restriction causes an increase in velocity and a decrease in pressure.

A differential pressure transmitter is used to measure pressure between the orifice and the pipe flow stream. 

There is always a permanent pressure loss. No dirty liquids allowed.

Orifice differential pressure flowmeters can be constructed to measure gas, liquid or steam.

Orifice plates are primary flow elements which measure flow as a function of differential pressure.

A restriction with a relatively long passage having a smooth entry and exit.

A venturi produces less permanent pressure loss than an orifice but is more expensive.

They are often used in dirty streams because there is no build-up of the foreign material.

Venturi flow meters can be constructed to be either gas flowmeters or liquid flow meters.

Extended reading: What Is A Venturi Flow Meter?

Smooth entry and sharp exit. Permanent pressure loss is on the same level as an orifice, with the added ability to handle dirty and abrasive fluids.

A differential pressure transmitter is used to measure pressure between the nozzle and the pipe flow stream.

This type of differential pressure flowmeter technology can be constructed to measure either gas or liquids.

Extended reading​: What is a flow nozzle?

A device consisting of a Pitot tube and an annubar tube combined with static pressure ports.

The differential pressure between the two ports is the velocity head.

A differential pressure transmitter is used to measure pressure differential between the two ports.

This indication of velocity combined with the cross-sectional area of the pipe provides an indication of flow rate. 

Pitot tube flow meters can measure either liquids or gases.

Differential pressure is caused by centrifugal force between the inside diameter and the outside walls of the pipe elbow.

It does not introduce any additional pressure loss other than that caused by the elbow. 

A differential pressure transmitter is used to measure pressure between the walls.

This type of flow meter technology can be configured as either a gas or a liquid flow meter.

A wedge-shaped element that is perpendicular to the flow at the top of the conduit which means that the bottom part is unrestricted.

Therefore, it is useful in slurry measurement.   

A differential pressure transmitter is used to measure pressure between either side of the wedge.

However, this type of differential pressure flow meter technology can be constructed to work as either a gas or a liquid flow meter.

Consists of a V-shaped cone element placed at the center of the pipe which creates an annular space for the passage of fluid.

It has a lower permanent pressure loss than orifice flowmeter.

The cone element conditions the flow at the same time it is creating the pressure differential, providing for smoother and less noisy differential pressure readings vs. the orifice technology.  

A differential pressure transmitter is used to measure pressure before and after the cone. 

This type of differential pressure flow meter can be constructed to measure gases, liquids, or steam.

This type of flow meter relates a change in flow rate to the differential pressure across a spring-loaded cone.

The cone repositions itself to balance the force.  

This, in turn, changes the aperture for the flow.

Flow rate has a relationship with the differential pressure of the flow meter and the position of the spring-loaded cone.

A differential pressure transmitter is used to indicate flow.

This type of differential pressure flow meter technology can be constructed to measure either gas or liquids.

Flow rate is linearly proportional to the differential pressure and inversely proportional to the viscosity of the flowing fluid.  

A flow can be made laminar by passing through a bundle of small diameter tubes.

A differential pressure transmitter is used to measure pressure before and after the tubes.

This type of differential pressure flow meter technology can be constructed to measure either gas or liquids.

Featured DP Flow Meters for Sale

Orifice Plate Flow Meter
Integral DP Flow Meter
Venturi Flow Meter
Wedge Flow Meter
 Annubar Flow Meter
Metal Tube Rotameter

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Sino-Inst is a manufacturer of Differential Pressure Flow Meters. We supply more than 20 types of Differential Pressure Flow Meters. 30% are orifice plate flow meters. 30% are Annubar type flowmeters, and 40% are other differential pressure flowmeters,

Differential pressure flowmeter is a new type of transmitter integrating differential pressure transmitter, pressure transmitter, temperature transmitter, and flow totalizer. It can display working pressure, temperature, instantaneous and cumulative flow. It can also perform automatic temperature and pressure compensation for gas and steam, and realize the function of directly displaying the standard flow rate and mass flow rate on site. In the case of an external 24V power supply, it can also provide current, frequency, and 485 personnel transmission. And it can work for 2-3 years with one battery, and can be directly matched with differential pressure flowmeters.

There are many types of differential pressure flowmeters, such as orifice flowmeters, uniform velocity tube flowmeters, and Venturi flowmeters are based on flow sensing in pipelines. They calculate the flow according to the differential pressure generated by the flow detection in the pipeline. They have the advantages of firm structure, stable performance and long service life.

Sino-Inst has provided pressure measurement solutions to customers for many years. Our Differential Pressure Flow Meters, made in China. Widely exported to the United States, Britain, Germany, South Africa, Norway and other countries.

If you need Differential Pressure Flow Meterss, but have technical questions, please feel free to contact our sales engineers.

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Water Pressure Transducers

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Pressure Transducers and Water Pipe Pressure Measurement

Water pressure transducers also called a water pressure sensor,
are pressure transmitters that can measure water pipe pressure.

For the water level/water depth measurement,
in the tank, or in the well, we can use electrical transmitters, stainless steel body, IP65-IP6, 4-20ma output.

Sino-Inst applies application expertise to design and manufacture pressure sensors and transducers for the water industry.

Various factors impact the selection and long term use of water pressure sensors and transducers, in residential, commercial, and irrigation systems.  

Sino manufactures various products with design features, to offer excellent accuracy and long term stability.

Below is some basic information to review, before making a decision on the type of pressure sensor technology, as well as the electrical and mechanical features required.

Sino-Inst also offers pressure transmitters with 0-5V/0.5-4.5V, just contact us now.

Water Compatibility

WATER PRESSURE SENSORS

A pressure sensing element will come in contact with varying pH levels, depending on the type of water, chemicals added, and the quality of the water purification process.

Sino packages pressure sensors using silicon strain gages, mounted onto a one-piece, 316L stainless steel sensing element.

316L SS offers excellent media compatibility for residential, and commercial water applications and is an NSF61 compliant material.

Environment

Rain, ice, dust, and pressure washers can cause water to seep into sensor housings, and cause the electronics to short.

Sino offers sealed gauge reference pressure sensors to protect the electronics from these conditions.

Electrical Isolation

Improper grounding and lightning strikes can cause electrical failures of pressure sensors, as a result of isolation failure.

Sino can include custom electronics and a sensing element to withstand 500VDC isolation to work in extreme electrical conditions.  

The use of a 4-20mA output signal for transmission lengths greater than 15 feet in environments with electrical noise, will help prevent signal loss or noisy signal conditions.

Read more about: What is a pressure sensor and how it works? 

Using Pressure Transducers for Water Pipe Pressure Measurement at Water Distribution Utilities

Inlet and Outlet Water Pipe Pressure Measurement in Clean Water Systems

Clean water systems use lift stations and gravity feed reservoirs, to pump water between locations.

In some residential settings, lift stations and water towers alone cannot supply enough pressure, to provide users at higher elevations with clean water.

Also, water reservoirs and water towers, that experience sudden, large draws of water need replenishment.

Pressure-controlled variable frequency drive pumps (VFDs) are used with pressure transducers, for reliable electronic pressure measurement to determine when extra pressure and flow are required by users.

Pressure transducers are used to monitor water pressure, at elevation, in reservoirs, and the rate of change in each.

VFD pumps interpret the pressure inputs and output the necessary increase or decrease in pump output pressure and flow rate.

Of course, in the water supply or wastewater treatment industry, the measurement of water flow is also very important. For example, if you need to measure the flow of wastewater in a 2-inch pipe. Then you can refer to Magnetic Flow Meters Guides.

Electronic Pressure Transducer Applications for Water Pipe Pressure Measurement in Clean Water Systems

Pressure transducers are used for inlet and outlet water pipe pressure measurement, in clean water systems at public utilities.

An electronic pressure transducer is typically used in water distribution applications such as:

  • Pump intake pressure measurement
  • Pump output pressure measurement
  • End location (reservoir, elevated piping, etc.) pressure measurement

An important part of pressure transmitter selection is ensuring that any electronic pressure transducer used is compatible with potable water.

Pressure transducers are responsible for monitoring the pressure, at various locations throughout clean water systems and often interface with VFD pumps to show, when increased pressure or flow rates are necessary.

The SI-200 and SI-390 electronic pressure transducers are designed for long lifetimes, in both inlet and outlet pipes of clean water systems.

They can usually be delivered within days in a wide variety of configurations.

In addition to measuring water pressure, you may also need to measure water depth. We also provide Portable Ultrasonic Water Depth Gauge.

How to select a water pressure transducer for water pressure?

  1. Absolute or gauge pressure measurement
  2. Cable or flying lead pressure transmitter wiring
  3. Media compatibility for pressure transmitters
  4. Moisture resistance in pressure transmitters
  5. Pressure transmitter accuracy and errors
  6. Radiofrequency (RFI) and electromagnetic interference (EMI) in pressure transmitters
  7. Standard or flush diaphragm pressure transmitters
  8. Vibration resistance in pressure transmitters

Read more about: What is industrial pressure transmitter?

Submersible water pressure sensor

Submersible pressure transducer with 4-20mA output is Hydrostatic Level Sensor for level measurement. Submersible pressure transducer is based on the measured liquid static pressure proportional to the height of the liquid Principle. Convert static pressure into electrical signal. After temperature compensation and linear correction. Convert into standard electrical signal. Generally 4 ～ 20mA / 1 ～ 5VDC. It can also be called “static pressure liquid level gauge, liquid level transmission Device, liquid level sensor, water level sensor “. Bullet, cage, and flush tip models are available. Applications include pumps, downhole, oil tanks, lime slurry, and water tanks. There is a miniature submersible transmitter that is low power voltage.

Extended reading: What is a pressure sensor?

Liquid pressure sensor for water pipe

SI-151 Hydrostatic Level Sensor
Hydrostatic Level Sensor (Best Price), also called Hydrostatic level transmitter. Continuous level measurement in liquid applications with pressure sensors.
SI-10 Liquid pressure sensor
Liquid pressure sensor is widely used for pressure measurement of various liquids. Like water or oils. IP68 waterproof.
SMT3151TR Submersible Level Transmitter
Hydrostatic level transmitter is also called hydrostatic level gauge. The rod-type Hydrostatic level transmitter 4-20mADC standard signal output. Flange or threaded installation. Can withstand high temperatures up to 450 ℃.
SI-PCM260 Deep Well Water Level Sensor
Well water level sensor is to apply Hydrostatic Level Sensor to deep well. Well water level sensor submerged in deep well work together with submersible water pump. Range 300m ～ 1000m.
SI-302 Anti-corrosive Submersible Level Transmitter
Submersible Level Transmitter is made of Anti-corrosive all-tetrafluoroethylene(PTFE) material. It has high temperature resistance, corrosion resistance and anti-clogging.
Extended Diaphragm Seal DP Level Transmitter Extended Diaphragm Seal DP Transmitter is a level transmitter direct mounted on pipe or tank. The isolation diaphragm is in direct contact with the liquid medium.
Remote Seal Differential Pressure Transmitter Remote seal differential pressure transmitter is used to prevent medium from entering transmitter. The pressure sensitive diaphragm and the transmitter are connected by a capillary filled with fluid. It is used to measure the level, flow and pressure of fluids, gases or steam.
Differential pressure(DP) level transmitter Differential pressure (DP) level transmitter is a perfect solution for tank level measurement. Flanges, seal diaphragms, capillaries, and DP transmitter are often used to measure liquid levels.

What are the different types of pressure sensors?

There 4 main types of pressure sensors based on this: 

More about Industrial Pressure Sensors

FAQ

How does a pressure transducer work?

The installation of the pressure transducer measurement system,
consists of three parts, namely the laying of the pressure guiding tube,
the laying of the electrical signal cable and the installation of the differential pressure transmitter.
During the operation of the pressure transmitter, the pressure of the medium is transmitted to the central measuring diaphragm.
Through the isolating diaphragm and the silicone oil, and the pressure difference from the double-sided pressure guiding tube is received on the double-sided isolating diaphragm, where the membrane is measured.
The sheet functions as a resilient element and is deformed by the pressure difference.
There is a positive proportional relationship, between the displacement of the measuring diaphragm and the differential pressure.
And under the influence of the displacement of the diaphragm, the capacitance of the differential capacitor also changes.
And the measuring circuit converts it into a DC current signal of 4-20 mA.
Extended reading: Hydrostatic Pressure Transmitter

Where are pressure transducers used?

Pressure transducers are mainly used in the following areas:
Petroleum, petrochemical, chemical. Matching with throttling devices to provide accurate flow measurement and control. Measures pressure and level in pipes and tanks.
Electricity, city gas. And other companies and businesses require high stability and high precision measurement and other places.
Pulp and papermaking are used in places that require chemical-resistant liquids and corrosion-resistant liquids.
Steel, non-ferrous metals, and ceramics are used in furnace pressure measurement and other places that require high stability and high precision measurement. They are also used in places that require stable measurement under strict control (temperature, humidity, etc.).
Machinery and shipbuilding, used to strictly control the place where high precision is required for stable measurement.
Extended Reading: 4 wire pressure sensor wiring diagram

What is pressure sensor and how it works?

A pressure sensor is a device or device that can sense a pressure signal and convert the pressure signal into a usable output electrical signal according to a certain rule.
A pressure sensor usually consists of a pressure-sensitive element and a signal processing unit. According to different test pressure types, pressure sensors can be divided into gauge pressure sensors, differential pressure sensors and absolute pressure sensors. A pressure sensor is the core part of pressure transmitter. More.
Extended Reading: Wireless Water Meter

Read more about: How to Calculate Pressure Drop in a Pipe?

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Capacitive pressure transducer

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A capacitive pressure transducer also called a Capacitance pressure transmitter or a Capacitance pressure sensor. The capacitive type pressure transmitter is a differential pressure type sensor.

What is the capacitive pressure transducer?

The capacitance pressure transmitter is a pressure measurement device, which converts an applied pressure into a current signal, Like 4-20mA.

A pressure transducer is a device that measures the pressure of a fluid, indicating the force the fluid is exerting on surfaces in contact with it.

Pressure transducers are used in many control and monitoring applications, such as flow, airspeed, level, pump systems, or altitude.

A pressure transducer consists of two main parts: an elastic material that will deform when exposed to a pressurized medium. And an electrical device that detects the deformation and converts it into a usable electrical signal.

The elastic material can be formed into many different shapes and sizes, depending on the sensing principle and range of pressures to be measured.

This often involves a diaphragm combined with an electrical device, that uses a resistive, capacitive, or inductive principle of operation.

Featured Capacitive pressure transducers

Capacitive Gauge Pressure Transmitter
Hydrostatic pressure transmitter
Flange Mounted Differential Pressure Transmitter
Smart Differential Pressure Transmitter
Extended Diaphragm Seal DP Level Transmitter

How does a capacitance pressure transducer work?

Capacitive Pressure Transducer Working Principle

A variable capacitance pressure transducer has a capacitive plate (diaphragm), and another capacitive plate (electrode) fixed to an unpressurized surface. With a gap of a certain distance between the diaphragm and the electrode.

A change in pressure will widen or narrow the gap between the two plates, which varies the capacitance.

This change in capacitance is then converted into a usable signal.

Capacitive Pressure Transducer Working Principle:

– A linear change in capacitance with changes in the physical position of the moving element, may be used to provide an electrical indication of the element’s position.

The capacitance is given by:

Technical Support

C = Aε/d

C – Capacitance between two conductors

A – Area of overlapping between those conductors

d – Distance separating the conductors

ε – Dielectric permittivity of the insulating medium

The permittivity of the medium and the area of overlapping will be constant in this case, the only varying parameter. In this case, is the distance between the conductors which varies when the pressure varies, which changes the capacitance.

So the pressure variation results in the capacitance variation. Our capacitance pressure sensor is shown below. Just like A Rosemount capacitance pressure sensor:

  • capacitance pressure sensor
  • Rosemount capacitance pressure sensor

The capacitance chamber is isolated from the process with an isolation chamber.

The pressure applied at one side. As the pressure at the high-pressure side increases the isolating diaphragm gets pushed toward the metal frame. Transferring its motion to the sensing diaphragm via the fill fluid.

The fill fluid will be oil.

A capacitance detector circuit connected to this cell uses a high-frequency AC excitation signal to measure the difference in capacitance between the two halves. Translating that into a DC signal ultimately becomes the signal output by the instrument representing pressure.

The simple capacitance detector connection with the electrical circuit is shown below:

capacitance detector connection

Advantages of Capacitive Pressure Transducer:

  • Inaccuracy 0.01 to 0.2%
  • Linearity
  • Fast response
  • Range of 80Pa to 35MPa

Disadvantages of Capacitive Pressure Transducer:

  • Temperature sensitivity
  • Stray capacitance problem
  • Vibration
  • Limited overpressure capability
  • Cost

Read more What is a diaphragm seal?

What does a pressure transducer do?

A pressure transducer is a measuring device which converts an applied pressure into an electrical signal.

Generally, a pressure transducer consists of two parts, an elastic material that deforms under the application of pressure. And an electrical part which detects this deformation.

Extended Reading: 4-20ma pressure transducer wiring diagram

Capacitive pressure sensor applications

Types of Pressure Sensors:

There are different types of pressure transducers based on their design.

These sensors can come in several shapes and sizes, but the technology inside can also differ. 

There 4 main types of pressure sensor based on this: 

  • Strain Gauge Pressure Transducers
  • Capacitance Pressure Transducers
  • Potentiometric Pressure Transducers
  • Resonant Wire Pressure Transducers

Know more about Industrial Pressure Sensors

Absolute measurements are generally used in applications where you need a repeatable reference pressure; i.e. in an experiment or in a barometric application.

For example, if you are looking to replicate a test that was originally completed by a colleague in Denver, CO and you are at a facility in Boston.

May you may want to use an absolute sensor to minimize variables in your test.

Other applications include weather stations, altimeter calibration equipment, and semiconductor fabs and many more.

However, if you want to measure or control a pressure that is based on current conditions a gauge sensor may be best.

Generally, if you want to measure or control a pressure that is influenced by changes in atmospheric pressure.

This style sensor is used in any application where you want to overcome the atmospheric conditions, to produce a task or pull a vacuum to accomplisher another type of task.

The applications for gauge pressure sensors are quite vast.

Some examples are pump discharge pressure, fire hose discharge pressure, tank level, steam pressure in a commercial boiler and many more.

Extended Reading: strain gauge pressure transducer

A sensor capable of compound pressure measurement is one that can measure both positive and negative (vacuum) pressures.

Often compound pressure ranges are utilized in applications, where different parts of a process may either be higher or lower than the atmosphere.

For example, if you were a manufacturer of a collapsible water bottle, in one part of the process you may pressurize a mold to form the bottle, but they pull a vacuum to release the part.

In this case, you may be able to use only one sensor instead of two to accomplish the same task.

Remember that Differential pressure is the difference in pressure between two points of measurement.

You can measure very low to high pressures in all kinds of different media including liquids, gases, water, refrigerants, and air.

Thus, if you want to measure the difference in pressure across a filter (see below), you could use a differential pressure transducer like 3151DP to tell you when it was time to change the filter.

So you can maintain the Indoor Air Quality (IAQ) of your building.

Differential applications can be quite varied, some examples supply and return pressure in a chiller, airflow stations, leak detection systems, pressurized tank level, hospital isolation or protection rooms, and many more.

Extended reading: Smart Differential Pressure Transmitter

How much does it cost a pressure transducer?

There are a number of factors that will impact the price of a pressure transducer.

The biggest differentiator is whether you can use a standard, off-the-shelf pressure transducer, or if you need a custom pressure transducer.

For an off-the-shelf pressure transducer, pressure transducer prices will be most affected by the level of accuracy required for your application.

The more accurate, typically the more expensive the pressure transducer.

To learn more about the pricing of custom pressure sensors click here.

Related Products

SI-303 Low-Pressure Transducer
Low pressure transducers for air and non-corrosive gases low pressure measurement. 0 ～ 2.5kPa to 0 ～ 30kPa measurable.
SI-350 Sanitary Pressure Transmitter
Sanitary Pressure Transmitter, also called tri clamp pressure transmitter,
is the pressure transducer with the flush diaphragm (flat membrane) as the pressure sensor.
SI-300 Pressure Transducer 4-20mA/Voltage
The 4-20mA/ Voltage Pressure Transducer,
also called pressure transmitter 4-20mA,
is a pressure sensor with4-20ma/Voltage output.
SI-512H High Temperature Pressure Sensor
High Temperature Pressure Sensor for pressure measurement of high temperature gas or liquid. Such as steam pressure. High temperature up to 800 ℃.
SI-706 Combined Pressure and Temperature Sensor-Dual function
Combined pressure and temperature sensor for Simultaneous measurement.
Thermocouple types: J, K, E type or PT100 platinum resistance. 
Absolute Pressure Transmitter
Absolute pressure transmitter with 4-20mA output for measuring pressure with absolute type reference. Absolute pressure (AP) transmitter is a measure of the ideal (complete) vacuum pressure.
Hydrostatic pressure transmitter
Hydrostatic pressure transmitter is used for fluid hydrostatic pressure measurement. With working static pressure up to 32Mpa, for liquid, gas or steam .
Diffused silicon Gauge Pressure Transmitter
A gauge pressure (GP) transmitter compares a process pressure against local ambient air pressure. Gauge pressure transmitters have ports to sample the ambient air pressure in real-time.
Capacitive Gauge Pressure Transmitter
Gauge pressure (GP) transmitters compare process pressure with local ambient air pressure. Gauge pressure transmitters have ports for real-time sampling of ambient air pressure.
Extended Diaphragm Seal DP Level Transmitter Extended Diaphragm Seal DP Transmitter is a level transmitter direct mounted on pipe or tank. The isolation diaphragm is in direct contact with the liquid medium.

In addition to pressure measurement, capacitive technology is also used in liquid level measurement. Read more about: Capacitive Level Measurement Principle.

Sino-Instrument offers over 50 Capacitive pressure transducers.

About 50% of these are 4-20ma Low-Pressure Transducers, 40% are Differential Pressure Gauge.

And 20% are Diaphragm Seal Pressure transmitters, 20% are 4-20ma differential pressure transmitters.

A wide variety of  Capacitive pressure transducers options are available to you, such as free samples, paid samples. 

Sino-Instrument is a globally recognized supplier and manufacturer of  Low-Pressure Transducers, located in China.

The top supplying country is China (Mainland), which supply 100% of  Capacitive pressure transducers respectively. 

Capacitive pressure transducers products are most popular in Domestic Market, Southeast Asia, and Mid East. 

You can ensure product safety by selecting from certified suppliers, with ISO9001, ISO14001 certification.

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Pressure indicator transmitters

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Pressure transmitters and transducers with industry-leading performance help improve operations in a wide range of industries

What is a pressure indicator transmitter?

Pressure indicator transmitters are industrial instruments,
which has a digital display for providing a local indication of pressure indicating,
and a 4-20 mA output pressure transmitter (which is also called the smart pressure gauge),
for sending an analog signal to control & monitor instrumentation.
The built-in digital indicators can be scaled via push buttons or change pots,
to any pressure unit or a 0-100% full scaling.
No additional external supply is required,
since the digital indicator is powered by the 4-20mA current loop,
from the pressure transmitter.

Sino-Instrument can offer pressure indicator transmitters for differential pressure measurement,

pressure level measurement, and water pressure measurement.

Pressure indicator transmitters can work with manifold, diaphragm seal, hart, orifice plate,

to measure different types of flow or level.

Pressure indicator transmitter

Pressure Indicators

by Sino-Instrument

  • More Reliable
  • Better Price
  • Many Years of experience in development and production

Contact us

Email: huahengxa@gmail.com
WhatsApp: +86-180 4861 3163
WeChat: +86-180 4861 3163
Mob: +86-18048613163

Types of the pressure indicator transmitters

The basis for an electronic pressure indicator is formed by the pressure sensor.

It converts the measurement parameter of pressure into an electronic signal.

The advantage of electronic pressure indicator lies

in the excellent dynamic performance and low material stress.

This gives them a high load resistance and long-term stability.

They are available in very small sizes.

Sino-Instrument develops and produces all leading sensor technologies:

The ceramic thick film, metal thin film and piezoresistive.

Electronic assemblies or components are integrated into a mechanical pressure indicator.

The measured pressure is displayed locally, however,

besides, the pressure indicator offers an electrical signal,

or includes an electrical switching function.

With these instruments, the measured value can also be read reliably on site,

if the power supply fails or the measuring signal is disrupted.

With the combination of mechanical pressure indicators with different signals and switches,

this results in a comprehensive range of mechatronic pressure indicators.

For our pressure indicators, we use the latest sensor technologies,

tested millions of times over in automotive applications.

They work without any kind of mechanical contact,

consequently, they are wear-resistant,

and there’s absolutely no influence on the pressure indicator.

Because of their robustness and simple handling,

indicating pressure indicators are widely used.

Their elastic pressure elements deform under the influence of pressure.

The measuring system is made from a capsule element,

diaphragm element or Bourdon tube.

The measuring systems are made from copper alloys, alloyed steels or,

if required for specific measuring tasks, from special materials.

Sino-Instrument manufactures mechanical pressure indicators,

with scale ranges from 0 … 0.007 psi up to 0 … 100,000 psi with indication accuracies of up to 0.1 %.

For pressure measurement with high dynamic pressure loads or vibration,

you will find mechanical pressure indicators with liquid filling in the Sino-Instrument portfolio.

Through their damping, they are optimally protected against destruction.

Even for the most demanding measuring requirements,

you’ll find the right solution with Sino-Instrument.

Diaphragm seals enable pressure measurement with harsh conditions such as,

for example, corrosive, highly viscous or fibrous media, very high temperatures,

awkwardly placed measuring points,

hygienic regulations or also toxic media or media harmful to the environment.

You may like:

Differential Pressure Flowmeters

Orifice flow meter

verabar flow meter

venturi flow meter

What is the function of a pressure transmitter?

The main function of the pressure transmitter is to transmit the pressure signal to the electronic device,

which in turn displays the pressure on the computer.

The pressure transmitter amplifies the weak electrical signal collected by the pressure sensor,

to transfer or activate the control element.

Or a signal source that converts the non-electricity of the sensor input,

into an electrical signal while amplifying it for remote measurement and control.

The analog quantity can also be converted to a digital quantity as needed.

The pressure sensor converts the mechanical pressure value into a proportional electrical signal.

The pressure sensor typically consists of a stable main body and a (thin) diaphragm.

The diaphragm is the most important element for the measurement of the pressure,

and is equipped with strain-sensitive and compression-sensitive resistance structures,

so-called strain gauges (DMS).

The diaphragm is deflected under the influence of pressure.

Thus, the strain gauges attached to it are elongated or compressed,

and its electrical resistance changes.

This change in resistance is directly proportional to the pressure.

For example, if the resistors are wired to a Wheatstone measuring bridge,

the resulting electrical signal can be measured and transferred to an indicator.

You may like the pressure level transmitter

What is the difference between the pressure gauge and pressure indicator?

A pressure Indicator is an instrument that indicates pressure.

A pressure Gauge is also a type of pressure Indicator.

It is a mechanical device.

Pressure indicators can work on mechanical deflection (in case of pressure gauge) or Piezoelectric effect,

change in capacitance, change in inductance, etc.

These are generally digital type instruments.

What is the difference between the pressure switch and pressure transmitter?

A pressure switch is an active electromechanical device,

which measures the pressure in a system,

and when the pressure reaches too high or too low of a given setpoint,

the device will “switch” meaning it will open or close a circuit,

that powers a certain device (like an alarm system or a shutdown valve).

A pressure transmitter or pressure transducer, on the other hand,

is also an electromechanical device,

which measures pressure but instead of signaling a switch,

it merely sends a read-out signal of what the specific pressure value is to a remote location.

Usually, a pressure switch, rather than a transmitter,

will be used in pressure-system applications,

where safety is of paramount importance.

An oil wellhead, for example, can see some very high-pressure spikes,

and if the pressure reaches too high, a possible well blowout can occur.

A pressure switch in this application makes sense so that when the pressure reaches too high,

the switch can trigger a blowout preventer,

which can actuate to reduce pressure in the system.

In contrast, the pressure transmitter has no inherent mechanical switching element.

However, transmitters prove to be much more versatile in that,

via third-party software that interprets the given pressure reading,

they can be extremely useful for measuring efficiencies of pressure systems,

and can control many industrial functions,

such as inlets and outlets, chemical or fuel mixtures,

or can even act as a safety switch itself depending on how the software is set up to control the system.

Extended reading: Smart Differential Pressure Transmitter

How Does a Pressure Transmitter Work?
Pressure Transmitter Calibration

Sino-Instrument is pressure transmitters manufacturer in China.

We offer all types of Pressure indicator transmitters.

Like Direct Mounted, flange-mounted, single flange, double flange,

Remote Diaphragm Seals, High Static, Digital Remote.

Most of our pressure transmitters are used in oil, liquids,

DP transmitter, flow measurement, level measurement (like the ultrasonic level measurement),

density, and other process variables.

Pressure transducers are generally available with three types of electrical output;

millivolt, amplified voltage, and 4-20mA.

You can ensure product safety by selecting from certified suppliers,

with ISO9001, ISO14001 certification.

We will share more about instrument calibration, like the flow transmitter calibration.

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