Turbine Flow Meter Installation Guidelines and Troubleshooting

Posted on December 28, 2022 by KimGuo11

Turbine Flow Meter Installation Guidelines and Troubleshooting is compiled based on our Sino-Inst’s many years of experience in producing and supplying turbine flow meters.
Whether it is a liquid turbine flow meter or a gas turbine flow meter. In order to ensure that the measurement of the turbine flowmeter is accurate. The installation location and installation precautions must be correctly selected.

RFQ Turbine Flow Meters

Turbine Flow Meter Installation Guidelines and Troubleshooting

Liquid Turbine Flow Meter Installation Guidelines

Installation Location

The sensor should be installed in a place that is easy to maintain, has no vibration in the pipeline, and is not affected by strong electromagnetic interference and heat radiation.

A typical installation piping system for a turbine flowmeter is shown in the figure.

1 – entrance;
2-valve;
3 – filter;
4 – air eliminator;
5- front straight pipe section;
6 – sensor;
7- rear straight pipe section;
8-Bypass

The configuration of each part in the figure depends on the situation of the measured object, not necessarily all of them.

Turbine flowmeters are sensitive to distortion of flow velocity distribution and swirling flow in the pipeline, and the flow into the sensor should be fully developed. Therefore, the necessary straight pipe section or flow regulator should be equipped according to the type of choke on the upstream side of the sensor, as shown in the table below.

If the condition of the upstream side choke is not clear, it is generally recommended that the length of the upstream straight pipe section is not less than 20D, and the length of the downstream straight pipe section is not less than 5D. If the installation space cannot meet the above requirements, a flow regulator can be installed between the choke and the sensor.

When the sensor is installed outdoors, measures should be taken to avoid direct sunlight and rain.

Type of spoiler on the upstream side	Single 90° elbow	Two 90° elbows on the same plane	Two 90° elbows on different planes	Concentric reducer	Fully open valve	Hhalf open valve	Downstream side length
L/DN	20	25	40	15	20	50	5

Installation Requirements for Connecting Pipelines

The sensor installed horizontally requires that the pipeline should not have a visually detectable inclination (generally within 5°). The verticality deviation of the sensor pipe installed vertically should also be less than 5°. The fluid direction must be upward when installed vertically.

Where continuous operation is required and the flow cannot be stopped, bypass pipes and reliable stop valves should be installed. When measuring, make sure that there is no leakage in the bypass pipe.

In the position where the sensor is installed in the newly laid pipeline, a short pipe is first inserted to replace the sensor. After the “line sweeping” work is completed and the pipeline is cleaned, the sensor is formally connected. Due to neglect of this task, it is not uncommon for wire sweeping to damage the sensor.

If the fluid contains impurities, a filter should be installed on the upstream side of the sensor. For those that cannot stop the flow, two sets of filters should be installed in parallel to remove impurities in turn, or self-cleaning filters should be selected.

If the measured liquid contains gas, a muffler should be installed on the upstream side of the sensor. The sewage outlet and air elimination outlet of the filter and muffler should lead to a safe place.

If the installation position of the sensor is at the low point of the pipeline, in order to prevent the impurities in the fluid from settling and stagnating. A discharge valve should be installed in the subsequent pipeline to discharge the precipitated impurities regularly.

The flow regulating valve should be installed downstream of the sensor, and the stop valve on the upstream side should be fully open when measuring. And these valves must not produce vibration and leak outward. For processes that may generate reverse flow, check valves should be added to prevent reverse flow of fluid.

The sensor should be concentric with the pipe, and the sealing gasket should not protrude into the pipe. Liquid sensors should not be installed at the highest point of the horizontal pipeline. In order to prevent the gas accumulated in the pipeline (such as mixed gas when the flow is stopped) staying at the sensor, it is not easy to discharge and affect the measurement.

The pipelines before and after the sensor should be supported firmly without vibration. For condensable fluids, thermal insulation measures should be taken for the sensor and its front and rear pipelines.

Installation Requirements

The pipe must be completely filled with liquid. It is important to keep the tubing completely filled with fluid at all times. Otherwise the traffic display will be affected. Measurement errors may result.
Avoid air bubbles. If air bubbles enter the measuring tube, the flow display may be affected, possibly causing measurement errors.

Straight pipe requirements

Generally
90° elbow
Two 90° elbows on the same plane
Two 90° elbows on different planes
shrink tube
Expansion
Fully open valve
half open valve
If the condition of the upstream side choke is not clear, it is generally recommended that the length of the upstream straight pipe section is not less than 20D, and the length of the downstream straight pipe section is not less than 5D.
If the installation control cannot meet the above requirements, a rectifier can be installed between the baffle and the sensor.

Gas Turbine Flow Meter Installation Guidelines

When installing the Gas Turbine Flow Meter, the user must carefully read the following content. Because the condition of the installation of the flowmeter directly affects the accuracy and life of the flowmeter, and even safety issues during work.

The installation work must be performed by personnel with corresponding pipeline equipment installation skills;
The flowmeter should be installed in a place that is convenient for maintenance, no strong electromagnetic field interference, no mechanical vibration and thermal radiation influence;
When the flowmeter is installed outdoors, there should be a cover on the upper part to prevent rainwater and hot sun from affecting the service life of the flowmeter;
When the flowmeter is installed, it is strictly forbidden to conduct electric welding directly at its inlet flange to avoid burning the internal parts of the flowmeter;
The newly installed or overhauled pipeline must be cleaned, and the flowmeter can be installed after removing the debris in the pipeline;
The flowmeter can only be installed horizontally, not vertically. The fluid flow direction should be consistent with the direction marked on the housing. There should be a straight pipe section ≥ 2DN upstream of the flowmeter, and a straight pipe section ≥ 1DN downstream of the flowmeter. Straight pipe section, and the filter of the corresponding specification must be installed at the upstream of the flowmeter (≥2DN) (the company can match) to prevent excessive particulate impurities in the pipeline from entering the flowmeter and affecting the service life of the meter;
The flowmeter should not be used in occasions where the flow is frequently interrupted and there is a strong pulsating flow or pressure pulsation;
Ensure that the connection between the pipeline and the inlet and outlet of the flowmeter is coaxial, and prevent gaskets and welds from protruding into the pipeline, otherwise the flow profile will be disturbed;
In order to facilitate the maintenance of the instrument, it is recommended to install the bypass pipeline according to Figure 6. Open the bypass when the instrument is maintained so as not to affect the normal production, and close the bypass pipeline during normal use.
When the flowmeter is put into operation, the upstream valve of the flowmeter should be slowly opened, and then the downstream valve of the flowmeter should be slowly opened, so as to avoid the instantaneous air flow that will destroy the turbine flowmeter;
The flowmeter must be reliably grounded as specified, but must not share the ground wire with the strong current system; during pipeline installation or maintenance, the ground wire of the electric welding system must not be overlapped with the flowmeter;
During use, users are not allowed to change the connection method of the explosion-proof system and change the lead interface arbitrarily;

Turbine Flow Meter Installation Troubleshooting

Fault phenomenon	Causes and Solution
1. There is no display when the liquid flows normally, and the cumulative volume does not increase	1) The power supply circuit or signal circuit is disconnected or poorly connected. Troubleshooting method: check with a multimeter to eliminate the fault point; 2) The printed circuit board of the display instrument, the connector is faulty or the contact is poor. Remedy: replace the printed circuit board; 3) The preamplifier is faulty. Troubleshooting method: Use an iron bar to move quickly under the detection head, if there is no signal output, check whether the coil is disconnected or the solder joint is desoldered; 4) The voltage supplied to the preamplifier is too low. Troubleshooting method: increase the power supply voltage to the specified requirements; 5) The impeller is stuck and does not rotate. Troubleshooting method: remove foreign matter, and clean or replace damaged parts, and re-calibrate after replacing parts;
2. When the flow is zero, the flow display is not zero, and the displayed value is unstable	1) Poor shielding and grounding of the transmission line, interference from the external electromagnetic field. Troubleshooting method: check the grounding and eliminate interference; 2) The pipeline vibrates, causing the impeller to vibrate. Troubleshooting method: strengthen the pipeline or install brackets before and after the flowmeter; 3) The shut-off valve is leaking. Troubleshooting method: overhaul or replace the valve; 4) Interference between circuit boards or electronic components inside the display is deteriorated and damaged. Troubleshooting method: take short circuit method”” or check one by one to find out the fault point;”
3. The displayed traffic does not match the actual traffic	1) The impeller is corroded and the blades are deformed. Troubleshooting method: Repair the impeller or re-calibrate after replacement; 2) The sundries hinder the rotation of the impeller. Troubleshooting: Clearing Debris; 3) The output signal of the detection coil is abnormal. Troubleshooting method: check the coil insulation resistance and conduction resistance; 4) The bypass valve is leaking. Troubleshooting method: close the bypass valve and replace it if necessary; 5) The flow velocity distribution upstream of the flowmeter is distorted or pulsating flow occurs. Troubleshooting method: find out the cause of distortion or pulsating flow, and take measures to eliminate it; 6) Display instrument failure. Troubleshooting method: repair display instrument; 7) The wiring of the display instrument is incorrect. Troubleshooting method: Correct the wiring; 8) Display instrument setting error. Troubleshooting: Correct settings; 9) The actual flow exceeds the specified flow range. Troubleshooting method: replace the flowmeter with a suitable caliber;

Featured Turbine Flow Meters for Sale

**Low temperature Turbine Flowmeter-Liquid Nitrogen Flow Meter**

Frequently
Asked
Questions

Help Center

Yes.
The flowmeter can be installed vertically.
As long as the full pipe measurement of the flowmeter is satisfied.

If the flowmeter is divided into 5 categories. Then the five commonly used flowmeters are:

Electromagnetic flowmeter
Differential pressure flowmeter
Turbine flowmeter
Ultrasonic flowmeter
Volumetric flowmeter (PD)

Natural Gas Pipeline Monitoring: Pressure-Temperature-Flow

Posted on December 27, 2022 by KimGuo11

As a clean energy, natural gas is widely used in many aspects such as industrial production, thermal power generation and residential gas heating.

Although natural gas pipeline transportation has many advantages, there are also risks such as leakage and failure. This can lead to interruptions or leaks in the delivery, causing significant financial losses and further safety risks. Therefore, sensors and data acquisition equipment are used for monitoring to achieve the purpose of leakage prevention and failure prevention. At the same time, risk issues such as distributed gas quality and consumption balance are monitored.

In the entire gas pipeline monitoring system, the detection of pressure-temperature-flow ensures operation, thereby preventing gas interruption.

RFQ

Natural Gas Pipeline Pressure Measurement

In the oil and gas sector, pressure sensors are fundamental components for a wide range of applications. The pressure sensor can be used to monitor the pipeline pressure in real time. Not only that, the pressure sensor is also used in the gas furnace to measure the pressure of the gas in the gas supply pipeline, so as to judge whether the gas is sufficient or whether it is leaking.

Pressure transmitters play an important role in moving natural gas through thousands of natural gas pipelines. For monitoring natural gas pressure, measuring very low inlet and outlet pressures;
Various pressure types are also involved in the measurement process. Such as gauge pressure, absolute pressure, differential pressure, high pressure and differential pressure, etc.;
Special approval options such as ATEX Intrinsic Safety are available where natural gas may be present in the local atmosphere;
Leaks and even explosions may occur if the gas pressure in gas and gas pipelines is too high;
If the air pressure is too low, it will affect people’s daily use. Therefore, it is necessary to monitor the air pressure of each node through the pressure sensor, so that the air pressure is within a reasonable range;
The gas pipeline pressure sensor generally adopts the threaded installation form, which is simple and convenient and easy to ensure the sealing of the product. The signal output of the gas pipeline pressure sensor has analog signal and digital signal, which belong to the remote transmission type signal.

Sino-Inst’s pressure transmitter can be matched with industrial control system PLC or configuration system to ensure the accuracy and reliability of the automation system. The most important thing to choose a gas pipeline pressure sensor is to consider the quality of the product. The Sino-Inst gas pipeline pressure sensor is made of a corrosion-resistant pressure core and a stainless steel outer protective shell thread to ensure the durability of the product. The signal expansion transmitter also uses imported electronic components to ensure the stability of the gas pipeline pressure sensor.

Regardless of oil drilling, extraction, or transportation, there are various challenges and difficulties in the application of pressure sensors in the oil and gas industry. For example, key issues such as cost control, safe construction and environmental protection. Our engineers have rich practical experience in this industry, can fully understand the problems and difficulties you actually encounter in the oil and gas industry, and provide you with pressure measurement solutions based on your needs, combined with our own technology.

Featured Natural Gas Pressure Transmitters

**SI-703 Flush diaphragm pressure sensor**

**SI-706 Combined Pressure and Temperature Sensor-Dual function**

**Capacitive Gauge Pressure Transmitter**

**Explosion-proof Pressure Transmitter**

**High-Temperature Pressure Transmitter**

**Diffused silicon Gauge Pressure Transmitter**

Monitoring of Natural Gas Pipeline Temperature

General-purpose temperature transmitter, suitable for temperature measurement of gas or liquid, such as air, natural gas, steam, water or engine oil and other non-corrosive media. At the same time, a variety of analog and digital signal outputs are available for selection. It is convenient for users to form a measurement and control system with other equipment.

The temperature transmitter is based on a standardized Pt100 or Pt1000 temperature sensing element, providing customers with accurate and stable temperature measurement. The product is cost-effective and can meet various application requirements. It is an ideal product for temperature measurement.

In addition to gas pressure detection, we also provide Industrial Gas Measurement with Digital Gas Mass Flow Meters.

Featured Temperature Transmitters

Natural Gas Pipeline Flow Monitoring

The flow measurement of natural gas is currently mainly used in trade settlement and is relatively common. my country’s natural gas trade measurement is based on the volume or energy method under the legally required quality indicators for transfer measurement. At this stage, volume measurement is basically the main method.

At present, the flowmeter products used for natural gas flow measurement generally include: gas waist wheel flowmeter, gas turbine flowmeter, precession vortex flowmeter, vortex flowmeter, ultrasonic flowmeter and orifice flowmeter.

Let’s make a simple comparison on the use of these flow meters.

Natural Gas Flow Meter Types

Featured Natural Gas Flow Meters

Different Types of Pressure: Absolute, Gauge, Sealed Gauge and Differential Pressure

Posted on December 23, 2022 by KimGuo11

Different Types of Pressure have different characteristics. Different pressure transmitters bear different pressure types. Common pressure types include absolute pressure, gauge pressure, negative pressure or vacuum, and differential pressure.

Each type of pressure works and causes differently. Therefore, when selecting, installing and using pressure transmitters, different types of pressure transmitters should be selected according to the specific pressure. At the same time, when measuring, it is necessary to have a detailed understanding of the specific specifications of the pressure transmitter.

RFQ Pressure Sensors

Different Types of Pressure

Gauge pressure is also called relative pressure. It is usually represented by “G”, and its reference point is atmospheric pressure. That is, the output point of the sensor is zero when the atmosphere is open. It can also be considered that the sensor does not consider the influence of atmospheric pressure on its measurement .

The sealed gauge pressure is usually represented by “S”. The sensor of the sealed gauge pressure uses an absolute pressure chip. However, when the output is calibrated, it is calibrated according to the output of the gauge pressure.

Absolute pressure is also called absolute pressure. It is represented by capital letter “A”. Its reference point is vacuum;

It is generally used to measure working conditions that may generate negative pressure. The absolute pressure gauge should display 102Kpa when it is not in use, which is the local atmospheric pressure.

Differential pressure: As the name implies, it refers to the difference between two pressures. That is, the difference between the pressure on the positive pressure end of the sensor and the pressure on the negative pressure end.

Applications of Different Types of Pressure

So what are the practical applications of these pressures?

Gauge pressure is usually used to measure without considering the influence of atmospheric pressure. For example, gauge pressure sensors are used in submersible liquid level transmitters.

Absolute pressure is just the opposite. Because its reference point is vacuum pressure. Many customers will choose absolute pressure sensors when measuring pipeline pressure.

Sealed gauge pressure is rarely used in practical applications. For diffused silicon pressure sensors, some customers will choose sealed gauge pressure in the scene of high humidity measurement. The purpose is to prevent water vapor from entering from the air hole behind the pressure core Pressure chip. This causes the instability of the output of the pressure chip. The failure phenomenon that often occurs in the use of sealed gauge pressure is that if there is a large difference between the atmospheric pressure at the sensor calibration location and the sensor user’s use location, the zero output of the sensor will appear A certain deviation. As a result, the accuracy deteriorates.

Differential pressure measures the difference between two pressures. So many customers use differential pressure to measure flow.

How to choose the pressure type?

Like temperature and Flow, pressure is one of the most important physical state variables. The different types of pressure are mainly distinguished based on the reference pressure. When measuring the pressure of liquid or gaseous media, the pressure type and pressure range are important factors for pressure transmitters.

Pressure range: such as ≤0.02MPa, ≥3.5MPa, 0.035MPa~3.5MPa.

Pressure type: gauge pressure, sealed gauge pressure, absolute pressure, gauge pressure, absolute pressure.

In layman’s terms, ordinary pressure gauges measure gauge pressure. Adding atmospheric pressure is absolute pressure, and there is a special absolute pressure gauge for measuring absolute pressure.

The pressure is taken at two different locations on the pipeline, and the difference between the two pressures is the differential pressure. The general differential pressure transmitter is to measure the differential pressure.

The sealing pressure is a pressure that is sealed in the back pressure chamber of the sensor as a reference pressure.

As atmospheric pressure may vary with location, weather and altitude. Therefore specific applications require different pressure types.

Whether it is absolute pressure, gauge pressure or differential pressure. If you are not sure which to choose. Our experienced and professional sales engineers are happy to assist you.

Read more about: What is Diaphragm pressure gauge?

Different Types of Pressure Transmitters

**SI-512H High Temperature Pressure Sensor**

**SIJC-1000HSM-Silicon Pressure Sensor**

The pressure transmitter is the so-called universal gauge pressure transmitter. One side is open to the atmosphere and the other side is connected to the measured pressure. It is used to measure the pressure of pipelines, boilers, etc. The pressure transmitter has only one impulse tube and measures pure pressure.

The differential pressure transmitter has two pressure pipes and measures the pressure difference. If the differential pressure transmitter is only connected to the positive membrane chamber or the negative membrane chamber, it is equivalent to the measurement of the pressure transmitter. The two sides of the differential pressure transmitter are respectively connected to different pressures. Measure the height of the liquid level according to the pressure difference and cooperate with the orifice plate to measure the flow of the pipeline.

One side of the absolute pressure transmitter is evacuated, and the pressure on the other side is absolute pressure. Suitable for absolute pressure applications.

The Micro differential pressure transmitter uses 2E capsule (0.0-1.5KPA) to improve the accuracy of measuring small pressure.

The high static pressure differential pressure transmitter uses a high static pressure capsule. The so-called static pressure means that when the pressure on both sides of the pressure transmitter is the same, its output current should be 4.00MA. However, when the pressure on both sides of the ordinary differential pressure transmitter increases to more than 25MPA at the same time, it is difficult to guarantee the output at 4.00MA. Therefore, high static pressure differential pressure transmitters are mostly used for flow, liquid level measurement and high pressure occasions.

What else can a pressure transmitter measure?

Liquid Level

Pressure transmitters and differential pressure transmitters measure pressure and differential pressure (the difference between the two pressures) by name. But they can be measured indirectly by a lot. In addition to measuring pressure, it can also measure the liquid level in the equipment.

When measuring the liquid level in an atmospheric pressure vessel, a pressure transmitter is all that is needed.
When measuring the liquid level of a pressure vessel, consider using two pressure/differential pressure transmitters. That is, one set for the lower limit of measurement and one set for the upper limit of measurement. They have to output signals for subtraction. The liquid level can be measured.

Density

It can also be used to measure the density of the medium when the liquid level and pressure in the container do not change.

Flow

The measuring range of the pressure transmitter can be made very wide. Starting from absolute pressure 0, it can reach more than 100 MPa (general situation). In addition to measuring the differential pressure value of the two measured pressures, the differential pressure transmitter. It can also cooperate with various throttling components to measure the flow rate of medium fluid.

Static Pressure Sensor and Transmitter Features and Applications

Posted on December 19, 2022 by KimGuo11

The application of Static Pressure Sensors and Transmitter in industry is not only to measure the pressure of pipelines or tanks, but also to measure liquid level. Let’s look at it in detail below.

RFQ Pressure Sensors

What is a static pressure sensor?

Static pressure sensors are often used to measure static air pressure. Such as the static pressure on air filters and cooling coils, the input and discharge pressure of blowers, etc.

In ventilation systems, static pressure is the pressure of the air inside the building relative to the air outside when the exhaust fans are turned on. Measuring and maintaining proper negative pressure allows ventilation systems to more effectively mix outside air with inside air.

Types

Diaphragm pressure sensors are based on the structure of the sensor. According to the sensing principle, diaphragm pressure sensors can be divided into different types such as piezoresistive, strain gauge, inductive, capacitive, and piezoelectric.

Among the above-mentioned pressure sensors with different principles, piezoelectric pressure sensors are only suitable for measuring dynamic pressure, so dynamic calibration is required;

Other dynamic and static pressures can be measured, and the most widely used one belongs to the quasi-static measurement with very low frequency. Therefore, static calibration is the most widely used calibration form. When the measured pressure frequency band is wide, all kinds of pressure sensors should be calibrated for frequency response.

Learn more about: Pressure Transmitter Calibration Formula

Hydro Static Level Transmitter

Hydrostatic level transmitters are based on the principle that the measured static pressure of a liquid is proportional to the height of the liquid. A device that converts static pressure into electrical signals by using the piezoresistive effect of diffused silicon or ceramic sensitive elements.

After temperature compensation and linear correction, it is converted into 4-20mADC standard current signal output.

The sensor part of the submersible static pressure liquid level transmitter can be directly put into the liquid. The transmitter part can be fixed by flange or bracket, which is very convenient to install and use.

**SMT3151TR Submersible Level Transmitter**

**SI-PCM260 Deep Well Water Level Sensor**

**Pressure Guided Submersible Level Transmitter**

Applications

For deep well level measurement, especially deep wells, we recommend submersible hydrostatic level transmitters.

The submersible hydrostatic pressure level transmitter is based on the principle of hydrostatics, which is converted into liquid level height through the measurement of liquid pressure. Fully sealed submerged measurement, integrated structure and standardized output signal. It provides convenience for on-site use and automatic control.

Then through reasonable selection and design of liquid-wetted materials, cables, protective tubes, etc. The liquid level of different media can be measured. It is suitable for deep mine liquid level measurement, groundwater level, hydrological detection, long-term underwater measurement of reservoirs, rivers, oceans, etc.

It is very important to ensure the full water level of the fire water tank and the high fire water tank, and to be able to monitor remotely in the fire control room.

Using the drop-in water level sensor, the water level probe is directly put into the bottom of the fire pool or water tank. In the fire control center, the real-time water level of the fire water tank can be monitored in real time. It also has a high and low liquid level alarm function to ensure that the fire water tank operates at a full water level.

Sino-Inst offers reliable pressure transmitter, level transmitter, and flowmeters for fire water tank/water treatment monitoring applications. Such as water management, sewage treatment, water purification treatment, etc.

High Temperature Pressure Sensor is used in industrial fields such as water plants, oil refineries, sewage treatment plants, building materials, light industry, machinery, etc. to achieve the measurement of liquid, gas and vapor pressure.

Application examples:

Industrial field process pressure detection
Laboratory pressure calibration system
Nautical and shipbuilding
Aviation and aircraft manufacturing.
Air separation equipment and thermal power units

Cryogenic pressure transducer has small size, high measurement accuracy, high dynamic response frequency, strong corrosion resistance and long working life.

Our professional technical group provides you with customized services. This product is mainly used for: low temperature scientific experiment, liquid Oxygen, liquid nitrogen, liquid hydrogen, liquid helium, etc. Pressure and low temperature measurement of cooling tanks, cryogenic storage tanks, propellants, etc.
Cryogenic storage tanks for aerospace, aviation, naval vessels, etc.

Most of our liquid level sensors can output liquid level signals, such as 4-20mA signal, 0-10V signal, RS485 and so on.

However, the liquid level transmitter alone cannot calculate the liquid volume of tanks of different sizes. It’s too complicated. A separate recorder is required to calculate it.

Therefore, the digital display volume meter can collect, display and convert the liquid level of various regular and irregular tanks in the industrial field into the corresponding tank volume. It is suitable for monitoring, controlling and collecting various process parameters.

Read More about: Common Pressure Sensor Applications

Ship Ballast Tank Pressure-Liquid Level Measurement

Posted on December 12, 2022 by KimGuo11

Ship Ballast Tank is to point to the ship’s ballast tank to load ballast to adjust the ship’s draft and metacentric height. It is an operation to ensure that the ship has good seaworthiness. Water is commonly used as ballast.

In bulk cargo transportation, since the cargo flow is usually one-way, the ship has to sail for a long distance without a load. In order to obtain the necessary draft to ensure the efficiency of the propeller and to obtain the necessary metacentric height to ensure safety. The ship must be loaded with a large number of of ballast water.

RFQ Pressure Sensors

What is a ship’s ballast water system?

Ballast water is critical to the safe and efficient operation of shipping. Wing and double bottom tank ballast water level measurement is used to control trim, draft and heel of ships, reduce hull deformation and improve empty space seaworthiness.

At the same time, ballast water poses a serious threat to marine ecology, economy and public health. In order to protect the ecological environment, protect public health and property safety. According to the International Maritime Organization regulations, ships must be equipped with ballast water treatment equipment.

The ship ballast water system varies according to the type, purpose and tonnage of the ship. The location, size and number of ballast water tanks on the ship also vary. Generally, ships can use the fore peak tank, stern peak tank, double bottom tank, side tank, top side tank and deep tank as ballast water tanks, and cargo oil tankers can use cargo oil tank and ballast tank.

There are three types of pipeline layout for ship ballast water system: branch pipe type, main pipe type and pipe tunnel type;
The suction pipe in the ship’s ballast water tank should also have the function of adding water;
The ballast suction port of each ballast water tank shall be arranged at a position conducive to the discharge of ballast water;
In order to meet the working characteristics of the ballast water system and simplify the pipeline. The barge valve box is often used to adjust the ballast water in each ballast water tank;
The ship’s ballast water system shall be able to transfer the ballast water in and out of each ballast tank of the whole ship or transfer each other. Also can not use ballast pump, outboard seawater flows into ballast water tank automatically by pressure difference.

There are many types of ballast water management systems, all of which require measurement of incoming water flow, tank level and system pressure for control purposes. Since these instruments are essential, reliability and stability are an absolute must.

In addition to ballast water systems, Sino-Inst can also provide professional monitoring solutions for different systems such as water circulation cooling systems, ship water supply and ship sewage treatment.

Extended Reading: How many types of level transmitters are there?

Ship Ballast Tank Pressure Measurement

A pressure transducer (Pressure Transducer) is a device or device that can sense pressure signals and convert the pressure signals into usable output electrical signals according to certain rules.

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.

Pressure sensor is the most commonly used sensor in industrial practice. It is widely used in various industrial automatic control environments, involving water conservancy and hydropower, railway transportation, intelligent buildings, production automatic control, aerospace, military industry, petrochemical, oil wells, electric power, ships, machine tools , pipeline and many other industries.

The first type of pressure sensor commonly used on ships is the pressure sensor that measures the pressure of pipes and tanks. Pressure measurement for ships and other long-term operations in relatively harsh environments such as seawater and river water.

The sensor has a solid measuring element, which is not afraid of the influence of marine microorganisms, sediment, etc. on the sensor. IP68 protection level, 316L, titanium alloy outer shell, can work stably and reliably for a long time. It is widely used in the fields of ship ballast tank, ship boiler liquid level, pressure and other fields. It can simplify measurement and improve work efficiency.

Featured Pressure Transmitters for Ship Ballast Tank

**SI-390 Industrial Pressure Transmitter**

Ship Ballast Tank Level Measurement

Ballast water (ballast water) is water specially injected to keep a ship balanced.
Ballast water is an important guarantee for the safe navigation of a ship, especially for a ship that does not carry an appropriate amount of cargo. An appropriate amount of ballast water can ensure sufficient draft of the ship’s propeller, minimize the shaking of the ship’s hull caused by the ship’s wake, and maintain propulsion efficiency.

Corrosion-resistant contact liquid level meters and non-contact liquid level meters can be used on ships to provide effective monitoring for Ship Ballast Tank liquid level management.

Featured Level Meters for Ship Ballast Tank

**Alternative to VEGAPULS 64-80GHz FMCW Level Radar**

**SI-302 Anti-corrosive Submersible Level Transmitter**

**ULT-200A Ultrasonic fuel tank level sensor**

**ULT-100 Explosion-proof** **Ultrasonic Level Indicator**

More Pressure & Level Measurement Solutions

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Checklist: Pressure Transmitter 4-20mA Common Faults and Error

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Sino-Inst is a manufacturer of pressure sensors and liquid level sensors. We offer a wide range of transmitters for marine vessels (drilling platforms, ship ballast tanks, seawater pressure, seawater level).

If you have any technical questions, please feel free to contact our sales engineers.

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Sea Water Flow Measurement – Magnetic vs Ultrasonic Flowmeters

Posted on December 9, 2022 by KimGuo11

Sea Water Flow Measurement is becoming more and more important to many industries. Seawater can be directly used as production water in printing and dyeing, pharmaceutical, alkali making, rubber and seafood processing industries. Since seawater is widely used, the measurement and control of seawater flow is also crucial.

Sino-Inst supplies various sea water flow meters. Seawater is a kind of salt water, which is highly corrosive. Electromagnetic flowmeter and ultrasonic flowmeter are the most widely used in Sea Water Flow Measurement.

RFQ Flow Meters

Importance of Sea Water Flow Measurement

Seawater stores 96.54% of the earth’s fresh water, which contains a huge amount of minerals, energy and other resources. The current forms of seawater resources development and utilization mainly include: seawater desalination, direct utilization of seawater and utilization of seawater chemical resources.

In seawater desalination

In coastal cities and islands where water resources are seriously short. Mainly large-scale industrial seawater desalination projects. Mainly concentrated in high water consumption industries such as electric power and steel. Seawater desalination projects for islands used in offshore cities.

In terms of direct use of seawater

Mainly for seawater cooling applications. Among them, seawater DC cooling technology is mature and is mainly used in coastal thermal power, nuclear power, petrochemical, steel and other industries. Seawater circulating cooling technology has been gradually applied in the coastal power industry.

In the utilization of seawater chemical resources

It mainly includes salt production from seawater, potassium extraction from seawater, bromine extraction from seawater, magnesium extraction from seawater, etc. In addition to seawater salt production, the main products include bromine, potassium chloride, magnesium chloride, magnesium sulfate, and potassium sulfate.

Therefore, the utilization rate of seawater is getting higher and higher. Even in the future, people will find more favorable treatment and utilization of seawater. Among them, flow measurement before and after seawater treatment, or flow measurement before and after seawater use will become more and more important.

Difficulties in sea water measurement

Seawater is a highly corrosive fluid. Seawater is a very complex multi-component aqueous solution, which contains various ions such as sodium, potassium, calcium, magnesium, copper, zinc, manganese, etc. Its salt content is very high and it is highly corrosive.

Simultaneously, waves and tides create low-frequency mutual stress and impact metal parts. Marine microorganisms, attached organisms and their metabolites also produce direct or indirect accelerated corrosion processes.

Marine corrosion is mainly localized corrosion, which starts at the surface of the component and occurs in a small area. Examples include galvanic corrosion, pitting and crevice corrosion.

Therefore, it is very necessary to consider corrosion issues when selecting seawater flowmeter sensors.

Magnetic flowmeter to measure sea water

Electromagnetic flow is the preferred flowmeter for measuring the volume flow of liquids with a certain conductivity.
Electromagnetic flowmeter is a flow measuring instrument that works based on the principle of electromagnetic induction. It consists of sensors and transmitters.

Advantages

There are no moving parts and bluff bodies in the measuring conduit. Therefore, the pressure loss is very small, and there is no mechanical inertia, so the response is sensitive;
Wide measurable range: the turndown ratio is generally 10:1, up to 100:1. The flow velocity range is generally 1-6m/s, and can be extended to 0.5-10m/s. The flow range can be from 90mL/h to hundreds of thousands of m3/h. Pipe diameters can range from 2mm to 2400mm or 3000mm.
It can measure the volume flow of liquids containing solid particles, suspended matter, or acids, alkalis, and salt solutions with certain conductivity. It can also measure pulsating flow, and can carry out two-way measurement.
There is a linear relationship between the flow signal and the fluid volume flow, so the meter has a uniform scale. And the volume flow rate of the fluid has nothing to do with the physical properties and flow state of the medium. Therefore, the electromagnetic flowmeter only needs to be calibrated with water, and it can be used to measure the volume flow of other conductive liquids without correction.
Compared with most other flow meters, the requirements for the front straight pipe section are lower.

Disadvantages

The temperature and pressure should not be too high;
The scope of application is limited. It cannot be used to measure the flow of non-conductive fluids such as gas, steam and petroleum products, and fluids containing more and larger bubbles;
When the flow rate and velocity distribution do not meet the set conditions, large measurement errors will occur;
When the flow rate is too low, it is difficult to amplify and measure the induced potential of the order of magnitude opposite to the interference signal. And the instrument is also prone to zero drift;
The signal of the electromagnetic flowmeter is relatively weak. A little interference from the outside world can affect the accuracy of the measurement.

Extended Reading: Special Magnetic Flowmeter Installation situation

Featured Magnetic flow meters for sale

**Magnetic Battery Operated Flow Meter**

ultrasonic flowmeter to measure sea water

Ultrasonic flowmeters are instruments that measure volume flow by detecting the action of ultrasonic beams (or ultrasonic pulses) when fluid flows.

The sound wave propagates in the fluid, and the sound wave propagation speed will increase in the downstream direction. , the countercurrent direction decreases, and the same propagation distance has different propagation times. The propagation time method is to calculate the flow velocity by using the relationship between the difference of the propagation velocity and the flow velocity of the measured liquid. Combined with the pipe diameter to obtain the flow rate.

Advantages

Ultrasonic flowmeter can be used for non-contact measurement. The clip-on transducer ultrasonic flowmeter can be installed without stopping the flow-carrying tube. Just install the transducer outside the pipeline to be tested. That is, the flow can be measured with an ultrasonic flowmeter on existing pipelines that cannot be cut off or drilled;
Ultrasonic flowmeters measure without flow obstruction. No additional pressure loss;
The instrument factor of the measuring meter can be calculated from the geometric dimensions of the actual measurement pipe and sound channel. The dry method can be used for calibration. Except for the type with measuring pipe section, it generally does not need to do real flow calibration;
Ultrasonic flow meters are suitable for large round and rectangular pipes. And it is not limited by pipe diameter in principle. Its cost basically has nothing to do with the pipe diameter;
Doppler ultrasonic flowmeters can measure liquids with high solid content or bubbles.

More about: Insertion Type Ultrasonic Flow Meter Applications

Disadvantages

The ultrasonic flowmeter in the propagation time method can only be used for clean liquids and gases, and cannot measure liquids with suspended particles and air bubbles exceeding a certain range. On the contrary, the Doppler method LSF can only be used to measure liquids containing certain heterogeneous phases;
Ultrasonic flowmeters with external transducers cannot be used in lined or heavily scaled pipes. And it cannot be used for stripping the lining (or rust layer) from the inner pipe. If there is gas in the interlayer, the ultrasonic signal will be seriously attenuated. Or pipes with severe corrosion (changing the ultrasonic path);
In most cases, the Doppler method ultrasonic flowmeter has a low measurement rate;
It cannot be used for pipes with a diameter smaller than DN15mm.

Read more about: Flow Meter Selection Guide

Featured ultrasonic flow meters for sale

**Insertion Ultrasonic Water Flow Meter**

conclusion

So, which flow meter should you choose for Sea Water Flow Measurement or salt water flow?
We believe that:

If the seawater concentration is low and the salinity is small.

Then ultrasonic flowmeter is a better choice. Such flow meters do not require contact with seawater and avoid corrosion.
At the same time, its flow sensor is not a metal part and is not afraid of corrosive materials.

For this type of seawater, if you choose an electromagnetic flowmeter. Then a 316L stainless steel electrode and rubber lining material should work well.

If the seawater has high concentration and high salinity.

Then the external clamp ultrasonic flowmeter is a better solution.

If you want to choose an online electromagnetic flowmeter for better performance. The best choice is Hastelloy C electrode and PTFE lining material. Hastelloy C electrodes are suitable for oxidation of salts such as Fe++, Cu++ and seawater.

For seawater desalination projects, plastic pipes are mainly used as water delivery equipment.

Many pipes are in the air. If an in-line electromagnetic flowmeter is used, the electromagnetic flowmeter is heavy. And the plastic tube doesn’t hold it in place very well. As a result, support brackets have to be installed, which adds a lot of cost and inconvenience.

Therefore, we recommend using a transit-time ultrasonic water flow meter. No pipe cutting required, light weight, easy installation, no maintenance etc.

If it is to measure the pipeline above DN3000.

Then the external clamp ultrasonic flowmeter is a better choice. For large diameter pipes, clamp-on ultrasonic flowmeters are less costly.

Stationary Torque Transducers

Posted on December 7, 2022 by KimGuo11

Stationary Torque Transducers are also called Static Torque Transducers, or Stationary Transducers.

Static torque transducers are compact, robust and maintenance-free, offering many advantages. Sino-Inst’s Stationary Torque Transducers are based on strain gauge technology and provide high-precision signal transmission. Designed to perform static torque measurements and dynamic rotation (limited angles) with high precision in both clockwise and counterclockwise directions.

RFQ Torque Sensors

Featured Stationary Torque Transducer for Sale

**11A Static Torque Sensor Flange-to-Shaft Mount**

**98 Flange-to-Flange Reaction Static Torque Sensor**

**17 Reaction Torque Sensor – Keyed Shaft**

**22 Static Torque Transducer with Internal Square-Flange Connection**

**12 Reaction Torque Sensor for Micro Range**

**120 Reaction Torque Sensor for Torque Wrench-Motor-Engine**

**2150 Dual Range Static Torque Sensor | Flange to Flange**

**56 Micro Reaction Torque Sensor | For Small Range, Tight Spaces**

**8050 Thin Hollow Type Reaction Torque Transducer Flange-to-Flange Mount**

Features

It is suitable for detecting the torque value of non-rotating body. The maximum deflection angle is ≯360 degrees.
It can enter the working state after turning on the machine, no preheating process is required.
High detection accuracy, good stability and strong anti-interference.
It can continuously measure positive and negative torque without repeated zero adjustment.
Small size, light weight, easy to install.
The sensor can be used independently from the secondary instrument, as long as the +24V power supply is provided according to the pin number of the socket, the current, voltage or frequency signal whose impedance is proportional to the torque can be output.

Stationary Torque Transducer Working principle

The static torque sensor has round shafts at both ends. It is praised by users for its excellent stability, high measurement accuracy, high cost performance and simpler monitoring method.

The measuring elastic body of the sensor does not participate in relative motion. The testing elastic body is subject to relative reaction force. When installing, one end is fixed and the other end is stressed.

Measurement of torque:
Using strain gauge electrical measurement technology, a strain bridge is formed on the elastic shaft, and the electric signal of the elastic shaft torsion can be measured by supplying power to the strain bridge.
After the strain signal is amplified, it becomes a frequency signal proportional to the torsional strain through voltage/frequency conversion.
Or directly output standard 4-20mA current signal and 1-5V voltage signal.

Read more about: Types Of Torque Transducers

Difference in Details: Pressure Transmitter vs Pressure Gauge

Posted on December 6, 2022 by KimGuo11

Do you know the difference between Pressure Transmitter vs Pressure Gauge? Pressure transmitters and pressure gauges are industrial process instruments used to measure the pressure of media.
Understanding the difference between Pressure Transmitter vs Pressure Gauge is something we should do before choosing a transmitter and a pressure gauge. Only in this way can we choose suitable products. Here we explain in detail the difference between Pressure Transmitter vs Pressure Gauge.

RFQ Pressure Transmitters

Pressure Transmitter

A pressure transmitter in the general sense is mainly composed of three parts: a load cell sensor (also called a pressure sensor), a measurement circuit, and a process connection. It can convert the physical pressure parameters such as gas and liquid felt by the load cell sensor into a standard electrical signal (such as 4~20mADC, etc.). Measurement, indication and process adjustment are carried out by supplying secondary instruments such as indicating and alarming instruments, recorders, and regulators.

A pressure transmitter is an instrument that accepts a pressure variable and converts the pressure change into a standard output signal in a certain proportion after being converted by sensing. The output signal of the transmitter is transmitted to the central control room for pressure indication, recording or control.

Extended Reading: Smart pressure transmitter

In fact, there are many kinds of working principles of pressure transmitters. Commonly used pressure transmitters can be divided into piezoresistive, diffused silicon, ceramic, piezoelectric and capacitive pressure transmitters according to the measurement principle of the pressure sensor.

Here, we use the piezoresistive pressure transmitter to introduce the working principle of the pressure transmitter.

The electrical components of pressure transmitters that sense pressure are generally resistance strain gauges.

The resistance strain gauge is a sensitive device that converts the pressure on the device under test into an electrical signal.

The most widely used strain gauges are metal resistance strain gauges and semiconductor strain gauges. There are two types of metal resistance strain gauges: wire strain gauges and metal foil strain gauges.

Usually, the strain gauges are tightly bonded to the mechanical strain-generating substrate through a special adhesive.

When the stress of the matrix changes. The resistance strain gauge also deforms together. Change the resistance value of the strain gauge. This changes the voltage across the resistor.

Pressure transmitter is the most commonly used sensor in industrial practice, and it is widely used in various industrial automatic control environments.

Petroleum/Petrochemical/Chemical
- It is matched with the throttling device to provide accurate flow measurement and control.
- Measures pressure and liquid level in pipes and storage tanks.
Electricity/city gas/other companies
- Places that require high stability and high precision measurement.
Pulp and paper
- Used in places that require resistance to chemical liquids, corrosive liquids, etc.
Iron and steel alloys / non-ferrous metals / ceramics
- It is used in occasions requiring high stability and high precision measurement such as furnace pressure measurement.
- For use in locations requiring stable measurements under strictly controlled (temperature, humidity, etc.) conditions.
Machinery/Shipbuilding
- It is used in places where stable measurement is required under strict control (temperature, humidity, etc.) and high-precision conditions.

According to different classification standards, pressure transmitters can be divided into different categories.
For example, depending on the type of pressure being measured. It can be divided into static pressure transmitter, absolute pressure transmitter, differential pressure transmitter and so on.

Commonly used pressure transmitters can be divided into piezoresistive, diffused silicon, ceramic, piezoelectric and capacitive pressure transmitters according to the measurement principle of the pressure sensor.

(1) piezoresistive pressure transmitter

One of the main components of piezoresistive pressure transmitters is the resistance strain gauge. It is a sensitive device that converts the strain change on the DUT into an electrical signal. When the stress of the matrix changes. The resistance strain gauge also deforms together. Change the resistance value of the strain gauge. This changes the voltage across the resistor. The transmitter has extremely low price and high accuracy and good linearity characteristics.

(2) Diffused silicon pressure transmitter

Diffused silicon pressure transmitters utilize the piezoresistive effect of elastic elements. When the pressure of the measured medium acts directly on the diaphragm of the sensor. The diaphragm produces a micro-displacement proportional to the medium pressure. Change the resistance value of the sensor.

Compared with traditional products, this transmitter has the advantages of advanced technology, reliable performance, convenient installation, high accuracy and small size.

(3) Ceramic pressure transmitter

Corrosion-resistant ceramic pressure transmitters have no liquid transfer. When the pressure acts on the ceramic diaphragm. The diaphragm deforms slightly. Make the thick film resistor printed on the back of the ceramic diaphragm pass through the Wheatstone bridge (closed bridge) connected to it. Output a voltage signal proportional to the excitation voltage. The pressure physical quantity is measured through the built-in circuit of the transmitter and converted into a unified standard signal.

The transmitter can introduce various media (corrosive and non-corrosive gases, liquids) directly to the ceramic diaphragm. The thermal stability of the ceramic and its thick-film resistance allow it to operate over a temperature range as high as -40°C to 135°C. Therefore, it has high measurement accuracy, good stability, strong output signal and low price.

(4) Piezoelectric pressure transmitter

Piezoelectric pressure transmitters work on the piezoelectric effect. The crystal is anisotropic, and when a force is applied along a certain direction, the crystal can produce an electric effect. When the mechanical force is removed, it will return to the uncharged state again.

The piezoelectric materials mainly used in sensors are quartz, sodium potassium tartrate and ammonium dihydrogen phosphate. The transmitter is mainly used in the measurement of acceleration and pressure. It has the characteristics of simple structure, small size, light weight and long service life. But it can only be used to measure dynamic stress.

(5) Capacitive pressure transmitter

The capacitive pressure transmitter is composed of a measuring diaphragm and electrodes on both sides of the insulating sheet to form a capacitor. When the pressure on both sides is inconsistent, the displacement of the measuring diaphragm 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. Then the pressure physical quantity is measured and converted into a unified standard signal through the transmission circuit. With its high precision, corrosion resistance, pollution resistance and good stability, it is recognized as an ideal instrument for detecting low vacuum pressure at home and abroad. It is mainly used in various fields of civil industry, and plays a unique role in military industries such as aerospace industry and nuclear industry.

More About：Low power-battery powered Wireless Pressure Sensors

Featured Industrial Pressure Transmitters

**Hygienic / Sanitary Pressure Transmitter**

Pressure Gauge

A pressure gauge refers to an instrument that uses elastic elements as sensitive elements to measure gas, steam, and liquid pressure. It is widely used. It is used in almost all industrial processes and scientific research fields.

The pressure value of gas, steam and liquid measured by the pressure gauge is called gauge pressure.

Gauge pressure is based on standard atmospheric pressure.

Instruments that measure pressure values above standard atmospheric pressure are called positive pressure gauges or pressure gauges.

Instruments that measure pressure values below standard atmospheric pressure are called negative pressure gauges or vacuum pressure gauges.

Instruments that can measure both positive and negative pressures are called pressure vacuum gauges.

It can be seen everywhere in heat pipe network, oil and gas transmission, water and gas supply system and other fields.

Bourdon tube pressure gauges are also known as Bourdon tube pressure gauges. The free end of the spring in the pressure gauge is closed, and it drives the sector gear to rotate through the pull rod.

During pressure measurement, the spring tube deforms under the measured pressure. Therefore, the free end of the spring tube produces a displacement. The displacement is proportional to the measured pressure. The pointer is deflected and the pressure value is indicated on the dial.

If there is atmosphere in the case, the pressure measured by the pressure gauge is positive or negative;
If the case is sealed and evacuated, the pressure measured by the manometer is absolute pressure.

When the spring tube pressure gauge is equipped with an isolation device, it can still measure the pressure of high temperature or corrosive, viscous, easy to crystallize and dusty media.

In elastic pressure measuring instruments with high precision (such as above grade), the elastic elements are mostly made of constant elastic alloy or even quartz glass.

Jewel bearings or rolling bearings are inlaid in the shaft holes of the transmission mechanism. The dial scale is long, and some can also be displayed digitally.

Pressure gauges have become a part of applications in various industries. They are used in many industries such as machinery, chemical industry, medical treatment, food, petroleum, shipbuilding, electric power, metallurgy, tap water, water treatment, environmental treatment, and power stations.

Simply put, a pressure gauge is based on atmospheric pressure and is used to measure instruments that are less than or greater than atmospheric pressure.

Commonly used pressure gauge uses are as follows.

1, to monitor the working condition of the medium filled inside the pressurized vessel in operation. in order to properly control the pressurized capacity and protect the safety of production equipment.

2, to understand the state of material changes in the production process. So that certain process parameters are controlled under the given conditions to ensure that the quality of the product meets the requirements.

3、By mastering the pressure parameters. To provide reliable data for the operator to monitor, control and regulate production.

According to different uses, pressure gauges can be divided into: diaphragm pressure gauges, stainless steel pressure gauges, ammonia pressure gauges, magnetic-assisted electric contact pressure gauges, shock-resistant pressure gauges, stainless steel diaphragm pressure gauges and many other types of pressure gauges.

The following is a brief introduction one by one:

(1) Stainless steel pressure gauge

Stainless steel pressure gauges are widely used in petroleum, chemical industry, chemical fiber, metallurgy, power station and other industrial sectors to measure the pressure of various fluid media in the process with high requirements for corrosion resistance and vibration resistance.

(2) Ammonia pressure gauge

The ammonia pressure gauge is mainly suitable for measuring the pressure of ammonia liquid, gas or its mixture in the process of fertilizer production or in refrigeration equipment.

It can also be used to measure the pressure of various non-corrosive, non-crystalline and solidified media such as ordinary carbon steel, austenitic stainless steel, platform metal structural steel, and tin brazing materials.

(3) Magnetic-assisted electric contact pressure gauge

Magnetic-assisted electric contact pressure gauges are widely used in petroleum, chemical industry, metallurgy, power stations and other industrial sectors or in supporting mechanical and electrical equipment to measure the pressure of various fluid media without explosion hazard.

Usually, the meter can be used in conjunction with corresponding electrical devices such as relays and contactors to achieve automatic control and send alarms for the measured and controlled pressure system.

(4) Shockproof pressure gauge

It is used to measure the pressure of gases or liquids that are non-corrosive to copper and copper alloys, non-explosive, non-crystallizing, and non-precipitating.

The biggest feature of the shock-resistant pressure gauge is that it can measure pressure normally in a machine tool or equipment that vibrates violently.

(5) Stainless steel bellows pressure gauge

The stainless steel bellows pressure gauge is a corrosion-resistant micro-pressure gauge developed with reference to the structural characteristics of the original bellows pressure gauge.

Applied to equipment such as boiler ventilation and gas pipelines, to measure the micro-pressure and negative pressure of various gas media in processes with high corrosion resistance requirements.

(6) Diaphragm pressure gauge

Diaphragm pressure gauges are suitable for measuring the pressure or negative pressure of various fluid media with certain corrosiveness, non-solidification or non-crystallization. Corrosion resistance depends on the diaphragm material.

Read more about: Calculation Of Pressure Drop

Difference list: Pressure Transmitter vs Pressure Gauge

The difference between a pressure transmitter and a pressure gauge are:

The standard instrument accuracy required for pressure transmitter calibration is much higher than the standard instrument accuracy required for pressure gauges.
The pressure gauge only needs to verify the relationship between a pair of input and output, while the pressure transmitter may need to verify the relationship between input and communication data.
The calibration of the pressure gauge must have the corresponding measurement qualification, and the pressure transmitter is generally not required except for the production plant and new construction.
The precision of the pressure gauge is poor, there is no output, and the manual operator cannot be used. Generally, 5 points are checked, and the back and forth difference is different. The intelligent pressure transmitter generally only needs to calibrate the zero point and full scale.
The output of the pressure gauge is a scale indication, which is displayed by itself. The pressure transmitter is a current output and must be connected to an ammeter of the corresponding accuracy level for display.

Checklist: Pressure Transmitter 4-20mA Common Faults and Error

Posted on December 4, 2022 by KimGuo11

Pressure Transmitter 4-20mA is the most commonly used one in industrial process control. In industrial process control, the measurement and control of pressure has always been a very important parameter. The 4-20mA output pressure transmitter is widely used due to its own characteristics, such as: good anti-interference performance, less and simple wiring, etc.

Sino-Inst sorted out the corresponding solutions according to the problems that customers often encountered in the process of installing and using this type of pressure transmitter. In particular, it pointed out that this article is aimed at common problems in the use of 4-20mA output pressure transmitters.

RFQ Pressure Transmitters

Featured 4-20ma Pressure Transmitters for Sale

**High Frequency Dynamic Pressure Sensor**

When checking whether the pressure transmitter can work normally, the tool we use most is the multimeter. After you confirm the output type of the pressure transmitter (common ones are 4-20 mA current type and 0-10V voltage type) and working voltage and other parameters. You can start the operation.

1. Pressure detection.

For current output type (4-20 mA): Set the multimeter to the current measurement function. And connected to the output loop of the pressure transmitter, connected in series.
For voltage output type (0-10V): Set the multimeter to the voltage measurement function. And connected in parallel at both ends of the output of the pressure transmitter.

Turn on the power and record the reading on the multimeter.

For a transmitter with a 4-20 mA output: With no pressure input, a current close to 4 mA should be displayed. At maximum pressure input, a current of approximately 20 mA should be displayed.
For a transmitter with 0-10V output: when there is no pressure input, a voltage close to 0V should be displayed. At maximum pressure input, a voltage close to 10V should be displayed.

Through the above methods, the status of a transmitter can basically be detected. If accurate detection is required, a standard pressure source is required. Apply pressure to the sensor and calibrate the transmitter according to the pressure and the change in the output signal. And when conditions permit, conduct temperature detection of relevant parameters.

2. Zero point detection.

Use the voltage range of the multimeter to detect the zero output of the transmitter without applying pressure. This output is generally a mV level voltage. If it exceeds the technical specifications of the sensor, it means that the zero point deviation of the transmitter is out of range.

3.Detection of bridge roads.

It mainly detects whether the circuit of the transmitter is correct, usually a Wheatstone full-bridge circuit. Use the ohm range of the multimeter to measure the impedance between the input terminals and the impedance between the output terminals. These two impedances are the input and output impedances of the pressure sensor. If the impedance is infinite, the bridge is open. It means there is a problem with the transmitter or the pin definition is not correct.

Troubleshooting for 4-20ma Pressure Transmitter

1. The pressure transmitter has no output and no display

Check whether the power supply is reversed. Connect the polarity of the power supply correctly
Measure the power supply of the transmitter, whether there is 24V DC voltage. It is necessary to ensure that the power supply voltage supplied to the transmitter is ≥12V (intelligent type) ≥15V (ordinary type). If there is no voltage, check whether the circuit is open or not, and check the secondary instrument/PLC sampling resistance (input impedance should be ≤250Ω)
If it has a head, check the head for damage. You can short-circuit the two wires of the meter head first. If it is normal after short-circuiting, it means that the meter head is damaged. Replace the header.
Connect the ammeter in series to the 24V power circuit to check whether the current is normal. If it is normal, it means that the transmitter is normal. At this time, you should check whether other instruments in the loop are normal.
Whether the wiring is loose. Connect the wires and tighten.
Whether the power supply is correctly connected to the power input terminal of the transmitter. Correctly connect to the power terminal according to the power requirements.

Extended Reading: Resistive Pressure Transducer

2. Pressure transmitter output ≥ 20mA

Whether the power supply of the transmitter is normal. If it is less than 12VDC, you should check whether there is a large load in the circuit. The input impedance of the transmitter load should comply with RL≤(transmitter power supply voltage-12V)/(0.02A) Ω.
Whether the actual pressure exceeds the upper limit of the full scale. Reselect a pressure transmitter with an appropriate range.
Whether the sensor is damaged. Severe overloading can sometimes damage the isolating diaphragm. It needs to be returned to the factory for inspection.
Whether the power cord is connected correctly. The power cord should be connected to the corresponding terminal.

3. Transmitter output≤4mA

Whether the power supply of the transmitter is normal. If it is less than 12VDC, you should check whether there is a large load in the circuit. The load capacity of the transmitter should comply with RL≤(transmitter power supply voltage-12V)/(0.02A)Ω.
Whether the wiring is loose causes the contact resistance to increase, which is equivalent to the increase of the load. Connect the wires and tighten them, and the load should meet RL≤(transmitter power supply voltage-12V)/(0.02A) Ω.
Whether the actual pressure exceeds the selected range of the pressure transmitter. Reselect a pressure transmitter with an appropriate range.
Whether the sensor is damaged, severe overload sometimes damages the isolation diaphragm. It needs to be returned to the factory for inspection.

4. The pressure display/output signal is incorrect and has errors

Whether the power supply of the transmitter is normal. If it is less than 12VDC, you should check whether there is a large load in the circuit, and the load capacity of the transmitter should meet RL≤(transmitter power supply voltage-12V)/(0.02A) Ω.
Whether the reference pressure value must be correct. Replace with the same model product. If the error is consistent, check the reference pressure gauge. If the accuracy of the instrument is low, another instrument with higher accuracy needs to be replaced.
Whether the range of the secondary instrument is consistent with the range of the pressure transmitter. The range of the adjusted secondary instrument must be consistent with the range of the pressure transmitter.
The load capacity of the transmitter should comply with RL≤(transmitter power supply voltage-12V)/(0.02A)Ω. If it does not meet the requirements, corresponding measures can be taken according to the difference: such as increasing the supply voltage (but must be lower than 36VDC), reducing the load, etc.
Whether the corresponding equipment casing is reliably grounded. The equipment shell is reliably grounded.
Whether the on-site strong current and weak current are wired separately. Scientific and reasonable wiring to avoid signal instability/error caused by interference.
The sensor diaphragm is easily deformed, and overload, foreign objects, and hard objects sometimes damage the isolation diaphragm. It needs to be returned to the factory for inspection.
Impurities in the pipeline will affect the measurement accuracy. Impurities need to be cleaned, and a filter is added before the pressure port.

Extended Reading: Smart pressure transmitter

5. The pressure control system cannot be connected

The input of the pressure indicating instrument is 4~20mA, and the output signal of the transmitter can be directly connected.
If the input of the pressure indicating instrument is 1~5V. Then a resistor with a precision of 1/1000 or above and a resistance of 250Ω must be connected to the input terminal of the pressure indicating instrument. Then connect to the input of the transmitter.

No matter which pressure transmitter you choose. The signal output by the pressure transmitter, such as 4-20mA. The pressure signal can be interfaced to a paperless recorder. Multi-channel pressure signal monitoring.

6. recorder no record

When the multipoint paper recorder does not record. If the input is open, then:

No other loads can be carried;
Use another recorder with input impedance ≤250Ω when there is no record.

7. The temperature of the pipeline is too high

The temperature of the pipeline is too high, add a buffer tube to dissipate heat. It is best to add some cold water to the buffer tube before use. In order to prevent the superheated steam from directly impacting the sensor. Thereby damaging the sensor or reducing the service life.

8. Pressure Transmitter 4-20mA installation problem

In steam flow measurement, steam mainly involves two kinds, one is external steam, and the other is superheated steam of boiler.

The externally supplied steam is the steam after decompression and decompression. The temperature is not high, and it is mixed with a lot of water. It needs to be used and not used. The steam flow rate can be changed according to the user’s requirements.

In the actual flow measurement process, sometimes the flow rate is too large and sometimes the flow rate is too small. It is very unstable. Blowdown is often required. The measurement of the transmitter is accurate after each blowdown. All joints on the pressure guiding pipe leak steam.

In the use of measuring superheated steam, the biggest problem found is that sometimes the machine shuts down, and the flow rate will deviate after restarting, resulting in inaccuracy. Sometimes there is still a little flow display after stopping.

Generally, the installation position of the transmitter is lower than the measuring pipe. But in the actual installation, the condensing tank and the transmitter for external steam flow are both higher than the measuring pipe, and the pressure guiding pipe that is laid down at least 1 meter from the throttling device is too short.

The superheated steam flow of the boiler also has the problem of inconsistent heights between the condensing tank and the measuring pipe. This leads to an imbalance in the height of the condensed water, which causes a static pressure difference.

9. Pressure guide pipe blockage problem

In pressure measurement, sometimes the indicated pressure does not vary with operating conditions. After opening the drain valve, there is only a small amount of sewage and no water flows out. This is because there will be a small amount of floating dust in the water quality or compressed air, which will enter the pressure guiding pipe for sedimentation along with the water flow. After a long period of operation, the wall of the pressure guiding pipe will be corroded and fouled, and blockage will occur.

10. Pressure Transmitter 4-20mA equipment itself fault problem

In the measurement of lubricating oil pressure, since the lubricating oil pressure signal participates in the shutdown interlock control. The signal measured by the lubricating oil pressure transmitter is transmitted to the computer. On the one hand, it is displayed. On the other hand, the signal is compared by the program. When the pressure is lower than 0.06MPa, it will send a signal to stop due to lack of oil.

From the trend graph of the lubricating oil pressure signal, it can be seen that the pressure is an instantaneous drop in a straight line, resulting in a trip. After checking the transmitter, it was found that the internal module of the transmitter was damaged. Although the transmitter is regularly calibrated every year, it is used for production after passing the test.

After several years of operation of the transmitter, its accuracy, sensitivity, stability and other performance indicators will gradually decrease. The internal diaphragm and integrated block will also be damaged and malfunction.

11. There is an interference problem

In the measurement of the exhaust pressure of the air compressor, the fluctuation of the exhaust pressure signal is large. After the transmitter is verified, it meets the accuracy requirements, and the fault of the transmitter itself is eliminated.

Check that the pressure guide tube and connector are not damaged or leaked. The connection of the signal cable is in good contact.
However, the direction of the cables is introduced into the control room through the cable bridge next to the high-end distribution room. There is a lot of electromagnetic interference around.

Learn More About Pressure Transmitter 4-20mA

A pressure transducer often called a pressure transmitter, is a transducer that converts pressure into an analog electrical signal.

Although there are various types of pressure transducers, one of the most common is the strain-gage base transducer.

The conversion of pressure into an electrical signal, is achieved by the physical deformation of strain gauges, which are bonded into the diaphragm of the pressure transducer, and wired into a Wheatstone bridge configuration.

Pressure applied to the pressure transducer produces a deflection of the diaphragm, which introduces strain to the gages.

The strain will produce an electrical resistance change proportional to the pressure.

A pressure transmitter is a device that converts pressure into a pneumatic signal or an electric signal for control and remote transmission.

It can convert the physical pressure parameters such as gas and liquid felt by the load cell sensor into a standard electrical signal (such as 4~20mADC, etc.). It can be used to supply secondary instruments such as indicating alarms, recorders, and regulators for measurement and indication. and process regulation.

4-20mA means that the minimum current is 4mA and the maximum current is 20mA.

The industry generally needs to measure various non-electrical physical quantities, such as temperature, pressure, speed, angle, etc. They all need to be converted into analog electrical signals before they can be transmitted to the control room or displays red meters of equipment away. This device that converts physical quantities into electrical signals is called a transmitter. The most widely used in the industry is to use a 4-20mA current to transmit analog quantities.

Because 4-20mA signals are least affected by electrical noise and resistance in the signal line, these sensors are best used when signals must be transmitted over long distances. These sensors are typically used in applications where the lead must be 1000 feet or more.

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.

In a pressure transducer, a thin-film or piezo-resistive pressure sensor is mounted on a process connection. The transducer converts pressure into an analog electronic output signal, typically as a millivolt per volt output. These signals are not linearized or temperature compensated.

A pressure transmitter has additional circuitry that linearizes, compensates, and amplifies the signal from a transducer. The different signal types are typically voltage signals (eg, 0 to 5 or 0 to 10 volts), milliamp (eg, 4 to 20 milliamp), or digital. The instrument then can transmit the signal to a remote receiver.

Two-wire transmission has specific requirements for its minimum supply voltage, output current, and transmitter power consumption.

Only when these three conditions are satisfied in the design can the two-wire transmission be realized. The four-wire system requirements are not as high as the two-wire system.

Therefore, the two-wire system and the four-wire system have different requirements for the electronic components of the whole circuit.

For the two-wire instrument, the output signal is mostly 4-20mA (there are also frequency signal output).

But the four-wire instrument has more output signals, such as current signal 4-20mA, 0-10mA, voltage (millivolt) signal, frequency signal, etc.

Read more about: Pressure Transducer Wiring: 2 Wire-3 Wire-4 Wire

If you cannot find an answer to your question in our Pressure Transmitter 4-20m, you can always contact us and we will be with you shortly.

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Industrial Gas Pressure Sensors and Transducers – Gas Pressure Measurement

Posted on December 2, 2022 by KimGuo11

What is a gas pressure sensor?

Gas Pressure Sensors are also called Gas Pressure Transducers. Gas Pressure Sensors convert gas pressure into standard electrical signals, such as 4~20mADC. Measurement, indication and process adjustment are carried out by supplying secondary instruments such as indicating and alarming instruments, recorders, and regulators.

Gas pressure measurement is widely used in the field of industrial process control for process control and monitoring. Different gases have different properties, so different pressure sensors and transmitters are required to measure different gas pressures. For example, measuring oxygen, hydrogen, chlorine, compressed air, high temperature gas, etc.

RFQ Pressure Sensors

gas pressure measurement

Gas pressure sensors are designed (or configurable) to measure gas pressure in different ways. In industrial settings, they can be used to measure the velocity of gas flow (sometimes called “shock pressure”), confirm the presence of suction, manage source pressure, or test for leaks.

(1). Gauge pressure is measured relative to ambient atmospheric pressure. Atmospheric pressure at sea level is about 100kPa (14.7 PSI). Sensors built into tire air pumps measure pressure this way, showing the air pressure inside the tire relative to the local atmospheric pressure. A reading of zero indicates equal internal and external pressure.

(2). Sealed air pressure sensors are similar to gauge air pressure sensors. But are pre-calibrated to measure air pressure relative to sea level atmospheric pressure. Therefore, if the device is taken to a different altitude or location, its readings will not change. More about: Diaphragm pressure gauge working principle.

(3). Vacuum pressure is a measure of the negative difference between the gas pressure at a given location and the atmospheric pressure.

In addition to gas pressure detection, we also provide Industrial Gas Measurement with Digital Gas Mass Flow Meters.

(4). Absolute air pressure is measured from zero or perfect vacuum (0 PSI). Again, unlike gauge pressure, this is not affected by the conditions surrounding the device. These conditions will vary with altitude and other factors.

(5). Differential pressure is the difference between two gas pressures. For example, the pressure difference in two gas hoses connected to the sensor. As with gauge pressure, a sensor may be able to measure changes in air pressure in either direction (i.e. positive or negative).

In addition to different types of measurements, some barometric pressure sensors are also designed to measure rapid pressure changes in dynamic environments. For example combustion pressure in engine cylinders or gas turbines.

Extended Reading: 4-20ma pressure transducer wiring diagram

Oxygen (O2) Pressure Measurement

Oxygen plays an important role in the smelting process, chemical industry, national defense industry, and medical care. However, the production and use of oxygen is extremely prone to combustion and explosion.

According to the mechanism of combustion and explosion “three elements” (combustibles, oxidants, excitation energy). The stronger, the more dangerous. Potential excitation energy sources for combustion or explosion are generally in the following ways: friction, compression heat, impact force, electric arc, resonance, etc.

For oxygen pressure measurement, a clean pressure sensor and a transmitter filled with inert oil is a safer choice. The risk of financial and time loss due to maintenance or faulty replacement is greatly reduced.

During the construction of industrial oxygen pipelines, multi-channel cleaning processes such as rust removal, scrubbing, sandblasting, blowing, degreasing, pickling, etc. should be carried out to remove oil and impurities in the pipelines so that they can meet the conditions for transporting oxygen media. And in accordance with relevant standards Check and accept. It can be used only after passing the test.

Extended reading: High accuracy pressure transducers

Featured Oxygen Sensors and Transducers

For oxygen pressure measurement, choosing a clean instrument filled with inert oil not only improves the safety level, but also greatly reduces the risk of economic and time loss caused by maintenance or failure replacement.

**SI-300 Pressure Transducer 4-20mA/Voltage**

Explosion-proof Pressure Transmitter

The pressure sensor for oxygen measurement supplied by Sino-Inst is required for the application of oxygen pressure measurement. The sensor product is filled with Fluorolube® oil. At the same time, oil-free technology is used for production. Finally, the sensor and transmitter are cleaned and packaged according to the oxygen level cleaning process.

The above sensors can be used in hazardous locations, including explosion-proof, intrinsically safe products. And it can be used in the occasions involving oxygen pressure measurement such as factories and hospitals.

The special pressure sensor for oxygen measurement must be cleaned strictly by oxygen grade cleaning process. Ensure that the sensor is clean and free of oil, corrosion, scaling, particles and other impurities. During the oxygen pressure measurement process, the potential risk of oxygen combustion or explosion caused by sensor oil pollution is completely solved.

Oxygen grade cleaning operations must be carried out in a dust-free and clean environment. To be operated by trained and qualified professionals. Use a special cleaning agent to clean the sensor and its accessories. Cleaning needs to go through multiple processes such as soaking, wiping, scrubbing, rinsing, drying, and sealing packaging. At the same time, during the cleaning process, special inspection equipment and precision instruments are used to conduct qualitative and quantitative inspections of the oil on the surface of the sensor. Make sure the sensor is clean.

Sino-Inst has an oxygen level cleaning platform, perfect cleaning process and quality control process. It cleans and seals the pressure sensor and pressure transmitter for measuring oxygen and high cleanliness.

Extended Reading: strain gauge pressure transducer

Hydrogen (H2) Pressure Measurement

Hydrogen (H2) is an extremely flammable, colorless, and odorless gas at normal temperature and pressure. Hydrogen has strong reducing properties and is a common industrial gas. It has a large number of applications in chemical, electronic, automotive, aerospace and other industries.

Hydrogen is easy to diffuse rapidly. When the ratio of hydrogen mixed with air exceeds 4%, it will become a combustible gas. Therefore, strict process and process control are required in the process of production, storage and transportation.

Since the hydrogen atom is very small, it will diffuse through the lattice of the diaphragm (usually stainless steel), thereby penetrating into the cavity filled with silicone oil. After long-term use, the infiltrated gas can damage the sensor.

Although gold is less permeable than stainless steel, gold-plated diaphragms are an effective way to prevent hydrogen permeation.

Extended Reading: Smart pressure transmitter working principle

Featured Hydrogen Pressure Sensors and Transducers

The pressure sensor dedicated to hydrogen measurement has many advantages in the pressure monitoring application of hydrogen production and purification equipment, hydrogen storage and transportation equipment.

In the process of measuring hydrogen pressure with a piezoresistive isolated pressure sensor. Since the atoms of hydrogen are very small, they will diffuse through the lattice of the diaphragm (usually stainless steel), thereby penetrating into the cavity of the sensor filled with silicone oil. Over time, the permeated gas can seriously affect the performance of the sensor. Effectively prevent the occurrence of “hydrogen embrittlement” and “hydrogen permeation”.

Measuring range: -100kPa…0kPa~35kPa…20MPa
Isolated structure, suitable for the measurement of hydrogen medium;
Pure flat membrane structure, using no dead angle full welding technology, the minimum thickness of gold plating layer is greater than 2μm;
The purity of gold plating on the surface reaches 99.8%;

The problem of hydrogen storage and transportation is an important factor affecting the cost of hydrogen. Pipeline hydrogen transportation has low cost and low energy consumption. It can realize continuous, large-scale and long-distance transportation of hydrogen energy. It is an important breakthrough direction for hydrogen storage and transportation problems.

It can be applied to hydrogen transportation scenarios such as hydrogen transportation vehicles. At the same time, it is also very suitable for pressure measurement of hydrogen storage cylinders and tank trucks and other gas and liquid hydrogen in hydrogen transportation.

Read more about: Types of biogas flow meters

Chlorine (CL2) Pressure Measurement

Chlorine is a simple substance formed by chlorine, with the chemical formula Cl2. It is yellow-green under normal temperature and pressure. It is a highly toxic gas with a strong pungent smell. It is suffocating and has a higher density than air.

Melting point -101.00°C, boiling point -34°C. Soluble in water and alkali solution, easily soluble in organic solvents (such as carbon tetrachloride), hardly soluble in saturated saline. It is easy to compress and can be liquefied into yellow-green oily liquid chlorine.

Generally, steel, iron, copper, nickel, etc. are resistant to dry chlorine, but once chlorine gas is mixed with a small amount of water, it will generate hypochlorous acid and hydrochloric acid, which are highly corrosive to most metals.

Therefore, pressure sensors and transmitters used for chlorine pressure measurement must use special corrosion-resistant housing and diaphragm materials to ensure reliable and accurate measurement.

More about: The Difference Between Absolute And Gauge Pressure

Featured Chlorine Pressure Sensors and Transducers

There are 2 types of chlorine pressure transmitters that are common:

Dry chlorine. Pure chlorine gas is non-corrosive. It can be said that it is economical and affordable to use ordinary pressure gauges to measure pressure.
Moist chlorine. If chlorine contains water, chlorine and water will react chemically to synthesize HCL and chloride ions. We all know that chloride ions are highly corrosive, and a special pressure transmitter must be used to measure pressure in order to resist the corrosion of chloride ions.

The pressure gauge used to measure chlorine gas containing moisture is a dedicated diaphragm pressure transmitter. The material of the instrument diaphragm isolator is 316L+F4, and the isolation diaphragm is 316L+F4. This diaphragm pressure transmitter is the most cost-effective. Isolation diaphragm can also choose Ta+F4. The price of this chlorine pressure transmitter is relatively high.

According to the actual situation of the user, select the chlorine gas pressure transmitter suitable for the actual situation on site.

Extended Reading: MEMS Pressure Sensors

High Temperature Gas Pressure Sensors

High Temperature Gas Pressure Sensor for pressure measurement of high temperature gas. High temperature up to 800 ℃.

High Temperature Pressure Sensor with high temperature resistant pressure core or sapphire core as pressure measurement material. After high reliability amplifier circuit and precise temperature compensation. The absolute or gauge pressure of the measured medium is converted into standard electrical signals such as 4 ~ 20mA, 0 ~ 5VDC, 0 ~ 10VDC. It is also widely used in industry. Collect pressure signals at the points of some high-temperature steam and fluid pipes.

Range: -100KPa ~ 0 ~ 100MPa optional
Accuracy: ± 0.5% FS (composite error including non-linear repeatability hysteresis)
Output signal: 4 ~ 20mADC (two-wire system), 0 ~ 10mADC, 0 ~ 20mADC, 0.5 ~ 4.5VDC, 0 ~ 5VDC, 1 ~ 5VDC, 0 ~ 10VDC (three wire system)
Power supply voltage: 5 ~ 40VDC (two-wire system), 15 ~ 40VDC (three-wire system)
Medium temperature: -40 ℃ ~ 200 ℃ -40 ℃ ~ 400 ℃ -40 ℃ ~ 600 ℃ -40 ℃ ~ 800 ℃
Ambient temperature: -30 ℃ ~ 105 ℃
Pressure connection: M20 * 1.5 M22 * 1.5 M16 * 1.5 M11 * 1 NPT1 / 4 NTP1 / 2 NTP3 / 8 G1 / 8 G1 / 2 G1 / 4 G3 / 8,1 / 2-20UNF, etc. Other threads can be according to customer requirements design

Frequently asked questions

There are many types of pressure sensors. The following are some commonly used pressure sensors.

Ceramic piezoresistive pressure sensor: with high precision and high stability of measurement. The electrical insulation degree is greater than 2KV, the output signal is strong, and the long-term stability is good. There is no choice between micro range and large range, it is only applicable to gauge pressure measurement.

Single crystal silicon pressure sensor: wide measuring range, high precision. Wide operating temperature, good stability, excellent static pressure characteristics. It has good one-way compression characteristics.

Capacitive pressure sensor: low input force and component Ru energy. High dynamic response, small natural effects. Good environmental adaptability.

Sapphire pressure sensor: The main advantage is that it can measure high-temperature media and is not sensitive to temperature changes. The drift in time at high temperature is the lowest among these types of sensors. Sapphire can be the most
The large range is up to 160MPa, while the maximum range of diffused silicon is 35MPa.

Quartz crystal pressure sensor: high frequency response pressure sensor, quick response. The digital output is stable and reliable, with strong anti-interference. Suitable for long-distance transmission, eliminating the analog
The complexities of digital conversion and the errors it creates.

Sputtering thin film differential pressure sensor: the outstanding feature is that it is less affected by temperature. When the temperature changes by 100°C, the zero point drift is only 0.5%. Its temperature performance is much better than that of diffused silicon, and it can
Features such as use under harsh environmental conditions.

Strain-type differential pressure sensor: The most widely used is the strain-type pressure sensor. It has extremely low price and high precision and good linear characteristics.

There are two types of resistance strain gauges: metal and semiconductor. Metal strain gauges are divided into wire type, box type, and film type. Semiconductor strain gauges have the advantages of high sensitivity and small lateral effects.

The above pressure sensors are commonly used by us. Each has its own characteristics, and the type is determined according to the needs when choosing.

For example, Below is a pressure sensor for measuring high temperature gas.
The parameters are roughly:

Pressure range: 0-30psig,
300 degrees Celsius high temperature
without local display;
4-20mA signal output;
Mounting thread 7/16″-20UN-2A (Male SAE-4);

The above parameters are customized according to user requirements. Even the body length of the sensor is customized to the 160mm length requested by our customer.

Read More: What Is A Pressure Sensor Example?

A pressure sensor is a device or device that can sense pressure and convert the pressure signal into an electrical signal output according to certain rules.

Pressure sensors usually refer to component-level products with non-standard mV signal output. They are the core components of pressure transmitters.

Pressure transmitters measure the liquid level, density and pressure of liquids, gases or vapors, acting on sensitive diaphragms. In general, a pressure transmitter is mainly composed of three parts: a load cell sensor (also called a pressure sensor), a measurement circuit, and a process connection.

It can convert physical pressure parameters such as gas and liquid felt by the load cell sensor into a standard electrical signal (such as 4~20mADC, etc.). It can be used to supply secondary instruments such as indicating alarms, recorders, and regulators for measurement and indication. and process regulation.

The installation position of the pressure transmitter on the process pipeline is related to the measured medium. The following conditions should be considered during installation:

Try to avoid direct contact between the transmitter and the corrosive or overheated measured medium.
To prevent dross from depositing in the pressure guiding tube.
The pressure guiding tube should be as short as possible.
The liquid column pressure in the pressure guiding tubes on both sides should be kept balanced.
The pressure guiding pipe should be installed in a place with small temperature gradient and temperature fluctuation.

When measuring liquid flow, the pressure tap should be opened on the side of the process pipeline to avoid sedimentation of dross. At the same time, the transmitter should be installed next to or below the pressure port so that the air bubbles can be discharged into the process pipeline.

When measuring gas flow, the pressure tap should be opened on the top or side of the process pipeline. And the transmitter should be installed next to or above the process pipeline so that the accumulated liquid can easily flow into the process pipeline.

When using a transmitter with a side relief valve in the pressure chamber, the pressure tap should be opened on the side of the process pipe. For example, when the measured medium is liquid, the relief valve of the pressure transmitter should be installed on it so as to exclude the gas infiltrated in the measured medium. When the measured medium is gas, the discharge valve of the transmitter should be installed below to discharge the accumulated liquid. The pressure chamber can be turned 180° so that the relief valve above it can be changed to the bottom.

The transmitter can be installed directly at the measuring point. It can be installed on the wall, or clamped on the pipeline with the installation plate (transmitter accessory).

Hydrogen embrittlement usually manifests as delayed fracture under stress. The phenomenon of delayed fracture occurs because the hydrogen in the part diffuses to the stress concentration part and gathers the metal defects in the stress concentration part (atomic lattice dislocation, holes, etc.).

Hydrogen diffuses into these defects, and hydrogen atoms change into hydrogen molecules to generate enormous pressure. This pressure and the residual stress inside the material and the external stress of the material form a resultant force. When this resultant force exceeds the yield strength of the material, fracture occurs.

Since hydrogen embrittlement is related to the diffusion of hydrogen atoms. Diffusion takes time, and the speed of diffusion is related to concentration gradient, temperature and material type.

A pressure transmitter is a device that converts pressure signals into electrical signals for control and remote transmission. Its core components are single crystal silicon resonant sensors and measuring capsules.

In order to reduce the pressure loss in the transmission process and prevent corrosion by the measurement medium. Generally, the metal thin-walled material with certain elasticity and anti-corrosion performance (the thickness is between 40 ~ 80um, which is slightly different for each equipment supplier) is selected to make the measuring diaphragm. Common measuring diaphragm materials include 316L stainless steel, Hastelloy, tantalum, titanium and many other types.

Since the thickness of the measuring diaphragm is less than 0.1mm, conventional pressure transmitters are prone to hydrogen embrittlement and are affected under harsh working conditions (high temperature and high pressure and high concentration of hydrogen). As a result, the toughness of the measuring diaphragm degrades and loses its elasticity, and cavity bulges or cracks appear.

Over time the hydrogen molecules can even penetrate the measuring diaphragm into the insulating silicone fluid. The presence of air bubbles increases losses during pressure transmission. It will also directly interfere with the measurement effect of the pressure transmitter, resulting in zero drift of the pressure transmitter and unstable output. Measurement errors and fluctuations in pressure measurement parameters occur. In more serious cases, the pressure transmitter may even be damaged, resulting in a safety accident.

Therefore, the selection of the measuring diaphragm of the pressure transmitter under the working condition of the coal gasification device is more important.

If you cannot find an answer to your question in our Industrial Gas Pressure Sensors and Transducers, you can always contact us and we will be with you shortly.

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What else can a pressure transmitter measure?

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