A flow meter is an instrument that indicates the flow rate to be measured and/or the total amount of fluid in a selected time interval. Simply put, it is a meter used to measure the flow of fluid in a pipe or open channel.
A flow meter also called a flow sensor, is a device or an instrument used to measure the linear, nonlinear, mass, or volumetric flow rate of a liquid or a gas.
If you need to know the flow rate in you pipe, or river, that when you need a flow meter. So, flow meter is the instrument that can finish the flow measurement.
Flowmeters consist of a primary device, transducer, and transmitter. The transducer senses the fluid that passes through the primary device.
The transmitter produces a usable flow signal from the raw transducer signal. These components are often combined, so the actual flow meter may be one or more physical devices.
Different types of flow meters are available for different applications, and depending upon the requirement, a careful selection of flow meters is made.
Turbine type flow meter cannot be used for measuring the flow in an unclear liquid (wastewater or corrosive liquids).
Flowmeters are devices that measure the rate of liquid, gas or vapor that passes through them.
Some flowmeters measure flow as the amount of fluid passing through the flowmeter during a time period (such as 100 liters per minute).
Other flowmeters measure the totalized amount of fluid that has passed through the flowmeter (such as 100 liters).
Flow measurement can be described by : Q = A x v
Q is flow rate, A is the crosssectional area of the pipe, and v is the average fluid velocity in the pipe.
Putting this equation into action, the flow of a fluid traveling at an average velocity of a 1 meter per second, through a pipe with a 1 square meter cross-sectional area is 1 cubic meter per second.
Note that Q is a volume per unit time, so Q is commonly denoted as the “volumetric” flow rate.
Now consider the following equation: W = rho x Q
Where W is flow rate (again – read on), and rho is the fluid density.
Putting this equation into action, the flow rate will be 1 kilogram per second, when 1 cubic meter per second of a fluid with a density of 1 kilogram per cubic meter is flowing.
(The same can be done for the commonly-used “pounds”. Without getting into details — a pound is assumed to be a mass unit.)
Note that W is a mass per unit time, so W is commonly denoted as the “mass” flow rate.
Now — which flow do you want to measure? Not sure? In some applications, measuring the volumetric flow is the thing to do.
Consider filling a tank.
Volumetric flow may be of interest to avoid overflowing a tank, where liquids of differing densities can be added.
(Then again, a level transmitter and high level switch/shutoff may obviate the need for a flowmeter.)
Consider controlling fluid flow into a process that can only accept a limited volume per unit time.
Volumetric flow measurement would seem applicable.
In other processes, mass flow is important.
Consider chemical reactions,where it is desirable to react substances A, B and C.
Of interest is the number of molecules present (its mass), not its volume.
Similarly, when buying and selling products (custody transfer) the mass is important, not its volume.
What are the types of flow meter? You may always hear words like: electromagnetic, vortex shedding, Coriolis, Ultrasonic, Venturi…. If you want to make better choice for your flow measurement, you may need to know more about the flow meter types. Flowmeters are used to measure the flow in a piping system. Let us see the types of flow meters by their different working principle.
Flow Metering Principles
From the measurement principle, the flowmeter can be divided into Volumetric flowmeters and Mass flwo meters.
Mass flow rate vs Volumetric flow rate is what we must use in flow measurement and control. In this post, we compare the concept of volume flow and mass flow and the conversion between the two.
Commonly used flow meters, such as orifice plates. Turbine flowmeter. Vortex flowmeter. Electromagnetic Flowmeter. Rotameter. The flow measurement value of the ultrasonic flowmeter and oval gear flowmeter is the volume flow of fluid. Coriolis mass flow meters and thermal gas mass flow meters measure mass flow.
When measuring flow, the temperature of the medium and the pressure of the pipe have a great influence on the measurement.
Different flow meters have for you the pressure and temperature tolerance range. More than the rated pressure and temperature range, it will affect the measurement accuracy of the flowmeter. Or even damage the flowmeter.
Therefore, when choosing a flowmeter, be sure to clarify the measurement of temperature and pressure.
Turbine flow meters are velocity flow meters, also called impeller flow meters. Used to measure the instantaneous flow and cumulative flow of liquids and gases.
The ultrasonic flow meter measures the liquid flow rate quickly and effectively. There are two types of ultrasonic flowmeter technology: Doppler frequency shift and transit time.
Ultrasonic Gas Flow Meter uses the principle of measuring the transit time of ultrasonic waves in the pipeline. Ultrasonic Gas Flow Meter is an ideal choice for various gas measurements.
Differential Pressure Flow Meter is also called DP flow meter. Differential pressure flow meters use the principle of differential pressure to measure the flow of liquid, gas and steam.
Volumetric Flow Meter, as a mechanical flow meter, is also called Positive displacement flowmeter. It can measure the volume flow of high viscosity and corrosive fluids.
Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects.
Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.
The industrial flow meter is one of the most important instruments in industrial measurement. In industrial sites, instruments that measure fluid flow are collectively referred to as flow meters or flow meters. There are very many kinds of flow meters. Based on years of experience, Sino-Inst has compiled the following information. Hope it can help you choose the right industrial flow meter.
Flow Measurement is the process of measuring fluid in your plant or industry. Sino-Inst offers industrial flow meters, with local LCD reading, transmitter, and optical set points. You can measure flow through a variety of different devices, such as Coriolis, differential pressure, vortex, magnetic, ultrasonic, turbine, and positive displacement meters. Industries like: gas flow, airflow, wastewater ( sewage ), pipe (like 4 inches), and etc.
If you need to know the flow rate in you pipe, or river, that when you need a flow meter. So, flow meter is the instrument that can finish the flow measurement.
Flowmeters consist of a primary device, transducer and transmitter.
The transducer senses the fluid that passes through the primary device.
The transmitter produces a usable flow signal from the raw transducer signal.
These components are often combined, so the actual flowmeter may be one or more physical devices.
Different types of flow meters are available for different applications, and depending upon the requirement, a careful selection of flow meters is made.
For e.g., we prefer vortex flow meters to flow steam flow measurement. And we like the ultrasonic flow meters for non-contact pipe flow measurement.
Turbine flow meters are velocity flow meters, also called impeller flow meters. Used to measure the instantaneous flow and cumulative flow of liquids and gases.
The ultrasonic flow meter measures the liquid flow rate quickly and effectively. There are two types of ultrasonic flowmeter technology: Doppler frequency shift and transit time.
Ultrasonic Gas Flow Meter uses the principle of measuring the transit time of ultrasonic waves in the pipeline. Ultrasonic Gas Flow Meter is an ideal choice for various gas measurements.
Differential Pressure Flow Meter is also called DP flow meter. Differential pressure flow meters use the principle of differential pressure to measure the flow of liquid, gas and steam.
Volumetric Flow Meter, as a mechanical flow meter, is also called Positive displacement flowmeter. It can measure the volume flow of high viscosity and corrosive fluids.
Mass flow meter directly measures the mass flow of the medium passing through the flow meter. It can also measure the density, temperature and viscosity of the medium.
INDUSTRIES
Sewage flow meter, also known as waste water flow meter. The sewage flow meter measures the flow of various sewages in pipes and open channels. Common sewage flow meters are magnetic flow meters, non-contact ultrasonic flow meters, etc.
Industries like the waste water, river water, industrial gas.
The air conditioning system is a control system that includes temperature, humidity, air clarity and air circulation, and is called HVAC (: Heating, Ventilation, Air-conditioning and Cooling).
The principle is similar to that of an air conditioner supplying cool air, heating air or dehumidification. The use of refrigerant under the action of the compressor. Produces evaporation or condensation. Then trigger the evaporation or condensation of the surrounding air, in order to change the purpose of temperature and humidity.
A chilled water flow meter refers to a flow meter that can be used to measure low-temperature water. Common chilled water flow meters include electromagnetic flow meters, turbine flow meters, and ultrasonic flow meters. Used in the condensing system, chiller, or HVAC.
The irrigation flow meter is a flow meter designed for agricultural irrigation water counting. Agriculture, horticulture, etc. require water for irrigation. And water is becoming more and more expensive. The installation of flow measurement devices allows for effective monitoring and management of agriculture water systems. The old mechanical water meters and today’s ultrasonic flow meters and electromagnetic flowmeters are widely used.
Industrial oil flow meters measure the volume or mass of oil. Can realize the mutual conversion of volume and mass.
The main industrial oils are hydraulic oil. Gear Oil. Turbine oil. Compressor oil. Refrigeration oil. Transformer oil. Cylinder oil, heat treatment oil, heat transfer oil, etc. Of course, edible oil can also be produced in the industry. In addition, there are greases with lubricating oil as base oil and thickening agent.
Therefore, whether it is a company that uses, trades, or produces oil, it needs to accurately measure the oil flow.
There are many common oil flow meters, such as turbine flow meters, positive displacement flow meters, gear flow meters, mass flow meters, etc.
Chemical flowmeters are used to measure flow rate that flow through them. You may often hear about ultrasonic flow meters, electromagnetic flow meters, turbine flow meters, volumetric flow or mass flow. Chemical flow meters are common in industries like petrochemical plants and refineries. And play a vital role in the manufacturing process since they help to enhance manufacture efficiency.
Common sanitary flow meters are sanitary magnetic flow meter and sanitary turbine flow meter. Composed of 304/316 stainless steel. Sanitary flowmeter with Tri-Clamp fittings is easier to install and disassemble. Suitable for food hygiene industry.
Marine fuels mainly include light diesel, heavy diesel, fuel oil, and residual fuel oil.
To put it simply, if the tested marine fuel is a low-viscosity, clean fuel. Then you can choose a turbine flowmeter. The price is reasonable and the measurement is stable.
If the marine fuel being tested is heavy oil, high-viscosity fuel. Then it is recommended to choose an oval gear flowmeter.
If the measured marine fuel is a small flow rate. Then it is recommended to use a circular gear flowmeter for measurement.
If the tested marine fuel has impurities. It is recommended to install a filter before the flowmeter.
If you still do not know how to choose the right marine fuel flow meter. You can contact our sales engineer. We will provide you with a suitable marine fuel flow measurement program.
The hydraulic flow meter is mainly for inline hydraulic system instantaneous flow test and high-pressure test. Industrial Hydraulic oil flow meter, also called hydraulic flow gauge.
Sino-Inst offers Turbine, Mass flow, Oval gear, V-cone, Target, and Orifice flow meters for inline hydraulic oil flow. Features like: bidirectional, high pressure, analog, can be customized as customer need
Commonly used Cryogenic Flow Meters include cryogenic turbine flow meters, orifice flow meters, mass flow meters, target flow meters, etc. Representative cryogenic fluids include LNG (liquefied natural gas), LN2 (liquid nitrogen), LO2 (liquid oxygen), liquefied ethylene, liquid hydrogen, liquid chlorine and these cryogenic gases. LPG (liquefied petroleum gas) is not included in the cryogenic Fluid.
Selecting the right industrial flow meter for your application can be a challenging task. To make it easy, Sino-Inst recommends the best flow meter you should use for your particular gas, liquid, or steam flow application. First, choose your application:
Natural gas
Compressed air measurement
Gas mixing and blending applications
Burner control
Liquid measurement
Steam flow measurement
Based on your application specifications, such as flow rate, pipe size and gas measured, we help you select the perfect flow meter solution for your industry,to improve quality and save money on energy costs, installation, and maintenance.
Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects.
Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.
Ultrasonic flow meters, using the ultrasonic principle, measure the velocity of flow.
We can use a different type of ultrasonic flow meters, like: Portable ultrasonic flow meter, Handheld ultrasonic flow meter, Clamp-on Ultrasonic Gas Flow Meter.
For airflow, natural gas, water, velocity measurement. There are two types of ultrasonic flow meter technologies: Doppler shift and transit-time. Transit-time measures the time differential between signals sent upstream and downstream.
The differential is directly proportional to the velocity of the water.
Transit-time meters are best used for measuring the flow of clean liquids and, as a result, are the most popular type of ultrasonic meter.
Doppler shift measures the difference in frequency of the sound wave, reflected off gas bubbles or particles in the flow stream, and is suitable for aerated or dirty liquids.
Ultrasonic flow meter advantages and disadvantages
Generally, an ultrasonic flow meter is the device, that uses ultrasound to measure the velocity of liquid flow, that helps in determining the volume of liquid flow also.
The ultrasonic flow meters are made using the ultrasonic transducers, which are clamped to the external surface of a pipe, to generate the ultrasonic pulses through the pipe.
When the liquid flows inside the pipe, it creates the time difference in the pulses, and these are examined to calculate the accurate flow velocity of the liquid.
There are many advantages of using the ULTRASONIC flow meters which include:
The electronics in the ultrasonic flow meter includes ultrasonic flowmeter detector which compensates and adapts to the changes in the profile of the flow, type of the liquid and material of the pipe.
A portable ultrasonic flow meter converter can be used as a direct method to determine the flow rates effectively when compared to the other flow systems.
Ultrasonic flow meter converter is inexpensive to use and maintain when compared to the other mechanical flow meters as they are no moving parts in these flow meters.
Their design is highly sophisticated and they do not obstruct the liquid flow, so they can be used for sanitary, corrosive and abrasive liquids.
These are the advantages of the ultrasonic flow meters and there are many disadvantages of the Ultrasonic flow meter which include:
The main disadvantage of the ultrasonic flow meter is the cost. The cost of the flow meter is very high when compared to the other types of mechanical flow meters.
The ultrasonic flow meters are sophisticated when compared to the mechanical flow meters, so it needs experts to repair and maintain the flow meters.
These are the advantages and disadvantages of the ultrasonic flow meters.
Ultrasonic flow meter Types
According to the measurement principle
(1) Time difference method ultrasonic flowmeter; (2) Frequency difference method ultrasonic flowmeter; (3) Phase difference method ultrasonic flowmeter; (4) Doppler ultrasonic flowmeter; (5) Ultrasonic flowmeters for partially full pipes and river channels that combine liquid level measurement and average velocity measurement.
Ultrasonic Clamp on Flow Meter is composed of an integrated host and external clamp on sensors. Clamp on Flow Sensors are available at room temperature and high temperature.
Clamp on flow meter (Model: 2000) is composed of an integrated host and ultrasonic clamp on sensor. Clamp on flow meter is widely used in online flow measurement of various liquids. Just stick the external clamp sensor on the pipe surface. Compared with the traditional flowmeter, it does not need to cut off the pipe and flow. The installation is convenient and quick, and the non-destructive installation is truly realized.
Portable Ultrasonic Flow Meter is a handheld ultrasonic flow meter. The clamp-on sensor is used to measure liquid flow in industrial pipelines.
Handheld ultrasonic flow meter realizes the non-contact measurement of liquid flow. Also often referred to as Portable Clamp-On Ultrasonic Flow Meter for Liquids.
Handheld Ultrasonic Flow Meter ( Model:2000H) has been successfully applied to measurement work in various industries. The measuring range is 20-6000mm (0.5-20 inches). A non-contact measurement method is adopted. Flexible operation and easy to carry. Conductive or non-conductive, corrosive or non-corrosive liquids can be measured. Various fluids: water, pure water, sewage, sea water, chemical fluids, river water, fuel Oil etc. can be measured.
Fuel flow meters, also known as turbine flow meters, are the main types of speed flow meters. A freely rotatable impeller is installed in the fluid flowing pipe. When the fluid passes, its motion can make the impeller rotate. The larger the fluid flow rate, the larger the kinetic energy and the higher the impeller speed.
The fluid flow can be determined by measuring the number of revolutions or the number of revolutions of the impeller.
Ultrasonic flow detector is also an ultrasonic sensor. Or called an ultrasonic flowmeter. Ultrasonic flow detector is composed of sensor and host. The host has wall-mounted, handheld, portable, etc. Sensors are classified into the following models according to the measuring pipe diameter and measuring temperature. It can help users measure pipeline flow under various working conditions.
Optional Transducer
Ultrasonic flowmeter refers to a flowmeter developed based on the principle that the propagation velocity of ultrasonic waves in a flowing medium is equal to the vector sum of the average velocity of the measured medium and the velocity of sound waves in a stationary medium.
It is mainly composed of transducer and converter, and there are different types such as Doppler method, velocity difference method, beam shifting method, noise method and correlation method.
Clamp-on or tube-segment ultrasonic flow meter is based on the principle of “velocity difference method”. It is an instrument for measuring the liquid flow in a circular tube.
Ultrasonic flow meters for measuring liquid flow. Measurement linearity is better than 0.5%. Repeatability accuracy is better than 0.2%. The time difference measurement resolution of up to 40 picoseconds enables the measurement accuracy to reach ±1%.
When choosing an ultrasonic flowmeter, the following points are mainly considered:
1.Measuring medium. 2. Pipe material. 3. Velocity range. 4. Diameter range. 5. Applicable temperature. 6. Medium turbidity. 7. Pipe lining. 8. Acceptable form of installation.
Specifications of Slurry Flow Meter Benefits of Magnetic flow meter for slurry Working Principle of Slurry Flow…
Sino-Inst, Manufacturer for Ultrasonic Flow Meters. It can measure a single sound-conducting liquid medium of DN 25—150mm. It can measure even liquids such as water, sea water, oil, and slurry.
Sino-Inst’s Ultrasonic Flow Meter, made in China, Having good Quality, With better price. Our flow measurement instruments are widely used in China, India, Pakistan, US, and other countries.
Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects.
Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.
Differential Pressure (DP) Flow Meters Technology – Reliable Flow Solutions Across Many Applications
Differential Pressure Flow meters, also known as DP flow meters. Differential Pressure (DP) flow meters introduce a constriction in the pipe, that creates a pressure drop across the flow meter.
The calculation of fluid flow rate, by reading the pressure loss across a pipe restriction, is the most used flow measurement technique in industrial applications.
You can take this as the definition of the differential pressure flow meter.
Differential pressure flow meters, also known as DP flowmeters, create a cross-sectional change in the flow tube, which causes the velocity of the flowing fluid to change.
A change in velocity occurs whenever there is a change in flow cross-section; ie, With a decrease in velocity, an increase in pressure occurs.
Differential pressure flow meters can be used as liquid flowmeters or gas flowmeters; however, a single flow meter may not be configured to measure both liquid and gas phases.
Differential pressure (also known as throttling) Flow meters, are based on the throttling principle of fluid flow. It is one of the most mature and most commonly used methods for measuring flow in production. It is usually composed of a throttling device, which capable of converting the measured flow into a differential pressure signal, and a differential pressure gauge, and a display instrument, capable of converting the differential pressure into a corresponding flow value.
In the unit combination meter, the differential pressure signal generated by the throttling device, is often converted to a corresponding standard signal (electrical or pneumatic), by a differential pressure transmitter for display, recording or control.
The differential pressure flow meter is composed of a primary device (detection member), and a secondary device (a differential pressure converter and a flow display instrument).
The differential pressure flow meter is usually classified in the form of a test piece, such as an orifice flowmeter, a venturi flowmeter, a constant velocity tube flowmeter, a pitot tube principle-Pitoba flowmeter, and so on.
The secondary device is a variety of mechanical, electronic, electromechanical integrated differential pressure gauges, differential pressure transmitters and flows display instruments.
It has developed into a large-scale instrument with a high degree of categorization (series, generalization, and standardization) and a wide variety of specifications.
It can measure flow parameters as well as other parameters (such as pressure, level, density, etc.).
Differential pressure flow meters use Bernoulli’s equation, to measure the flow of fluid in a pipe.
Differential pressure flow meters introduce a constriction in the pipe, that creates a pressure drop across the flowmeter.
When the flow increases, more pressure drop is created. Impulse piping routes the upstream and downstream pressures of the flowmeter to the transmitter, that measures the differential pressure to determine the fluid flow.
This technology accounts for about 21% of the world market for flow meters.
Bernoulli’s equation states that the pressure drop across the constriction is proportional to the square of the flow rate. Using this relationship, 10 percent of full-scale flow produces only 1 percent of the full-scale differential pressure.
At 10 percent of full-scale flow, the differential pressure flowmeter accuracy is dependent upon the transmitter, being accurate over a 100:1 range of differential pressure.
Differential pressure transmitter accuracy is typically degraded, at low differential pressures in its range, so flowmeter accuracy can be similarly degraded.
Therefore, this non-linear relationship can have a detrimental effect on the accuracy, and turn down of differential pressure flow meters.
Remember that of interest is the accuracy of the flow measurement system — not the accuracy of the differential pressure transmitter.
Different geometries are used for different measurements, including the orifice plate, flow nozzle, laminar flow element, low-loss flow tube, segmental wedge, V-cone, and Venturi tube.
Although these restrictions sound severe, the Bernoulli equation is very useful, partly because it is very simple to use. And partly because it can give great insight into the balance between pressure, velocity, and elevation.
Advantages and disadvantages of differential pressure flow meter
The upside of this technology is low cost, multiple versions can be optimized for different fluids and goals, are approved for custody transfer (though it is being used less and less for this). It is a well-understood way to measure flow. And it can be paired up with temperature/pressure sensors, to provide mass flow for steam and other gasses.
Negatives are that rangeability is not good due to a non-linear differential pressure signal (laminar flow elements excepted), accuracy is not the best and can deteriorate with wear and clogging.
Advantages and disadvantages of throttling differential pressure flow meter (orifice flowmeter)
Advantages:
1) The standard orifice plate structure of the throttle piece is easy to copy, simple, firm, stable and reliable in performance, long in service life and low in price;
2) The throttling application range is extremely wide. All single-phase fluids, including liquid, gas, and steam, can be measured. Some mixed-phase flows, such as gas-solid, gas-liquid, liquid-solid, etc. can also be applied. General production processes and pipe diameters, The working condition (pressure, temperature) has products;
3) All accessories can be used by all manufacturers if it is an international standard and can be used without calibration.
Disadvantages:
1) The repeatability and accuracy of the measurement are medium levels;
2) The range is narrow because the meter signal and the flow rate are squared, the general range can only reach 3:1 ~ 5:1;
3) The requirements for on-site installation conditions are relatively high. If a long straight pipe section is required, it is difficult to meet;
4) The pressure piping is a weak link, which is prone to leakage, blockage, freezing and signal distortion;
What is the relationship between flow and differential pressure?
Differential pressure use Bernoulli’s equation to measure the flow of fluid in a pipe.
Differential pressure flow meters introduce a constriction in the pipe, that creates a pressure drop across the flowmeter.
When the flow increases, more pressure drop is created.
y+P(x)y =Q(x)y^n (equation)
is called a Bernoulli differential equation where n is any real number.
The graph below shows the resulting pressure drop for water at 60 F, over a range of flow rates for a 100-foot long pipe, for both 4 inches and 6-inch schedule 40 piping.
the relationship between flow and differential pressure
A device consisting of a Pitot tube and an annubar tube combined with static pressure ports.
The differential pressure between the two ports is the velocity head.
A differential pressure transmitter is used to measure pressure differential between the two ports.
This indication of velocity combined with the cross-sectional area of the pipe provides an indication of flow rate.
Pitot tube flow meters can measure either liquids or gases.
Differential pressure is caused by centrifugal force between the inside diameter and the outside walls of the pipe elbow.
It does not introduce any additional pressure loss other than that caused by the elbow.
A differential pressure transmitter is used to measure pressure between the walls.
This type of flow meter technology can be configured as either a gas or a liquid flow meter.
A wedge-shaped element that is perpendicular to the flow at the top of the conduit which means that the bottom part is unrestricted.
Therefore, it is useful in slurry measurement.
A differential pressure transmitter is used to measure pressure between either side of the wedge.
However, this type of differential pressure flow meter technology can be constructed to work as either a gas or a liquid flow meter.
Consists of a V-shaped cone element placed at the center of the pipe which creates an annular space for the passage of fluid.
It has a lower permanent pressure loss than orifice flowmeter.
The cone element conditions the flow at the same time it is creating the pressure differential, providing for smoother and less noisy differential pressure readings vs. the orifice technology.
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Sino-Inst is a manufacturer of Differential Pressure Flow Meters. We supply more than 20 types of Differential Pressure Flow Meters. 30% are orifice plate flow meters. 30% are Annubar type flowmeters, and 40% are other differential pressure flowmeters,
Differential pressure flowmeter is a new type of transmitter integrating differential pressure transmitter, pressure transmitter, temperature transmitter, and flow totalizer. It can display working pressure, temperature, instantaneous and cumulative flow. It can also perform automatic temperature and pressure compensation for gas and steam, and realize the function of directly displaying the standard flow rate and mass flow rate on site. In the case of an external 24V power supply, it can also provide current, frequency, and 485 personnel transmission. And it can work for 2-3 years with one battery, and can be directly matched with differential pressure flowmeters.
There are many types of differential pressure flowmeters, such as orifice flowmeters, uniform velocity tube flowmeters, and Venturi flowmeters are based on flow sensing in pipelines. They calculate the flow according to the differential pressure generated by the flow detection in the pipeline. They have the advantages of firm structure, stable performance and long service life.
Sino-Inst has provided pressure measurement solutions to customers for many years. Our Differential Pressure Flow Meters, made in China. Widely exported to the United States, Britain, Germany, South Africa, Norway and other countries.
If you need Differential Pressure Flow Meterss, but have technical questions, please feel free to contact our sales engineers.
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Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects.
Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.
Pressure Transducers and Water Pipe Pressure Measurement
Water pressure transducers also called a water pressure sensor, are pressure transmitters that can measure water pipe pressure.
For the water level/water depth measurement, in the tank, or in the well, we can use electrical transmitters, stainless steel body, IP65-IP6, 4-20ma output.
Various factors impact the selection and long term use of water pressure sensors and transducers, in residential, commercial, and irrigation systems.
Sino manufactures various products with design features, to offer excellent accuracy and long term stability.
Below is some basic information to review, before making a decision on the type of pressure sensor technology, as well as the electrical and mechanical features required.
Sino-Inst also offers pressure transmitters with 0-5V/0.5-4.5V, just contact us now.
Water Compatibility
WATER PRESSURE SENSORS
A pressure sensing element will come in contact with varying pH levels, depending on the type of water, chemicals added, and the quality of the water purification process.
Sino packages pressure sensors using silicon strain gages, mounted onto a one-piece, 316L stainless steel sensing element.
316L SS offers excellent media compatibility for residential, and commercial water applications and is an NSF61 compliant material.
Improper grounding and lightning strikes can cause electrical failures of pressure sensors, as a result of isolation failure.
Sino can include custom electronics and a sensing element to withstand 500VDC isolation to work in extreme electrical conditions.
The use of a 4-20mA output signal for transmission lengths greater than 15 feet in environments with electrical noise, will help prevent signal loss or noisy signal conditions.
Using Pressure Transducers for Water Pipe Pressure Measurement at Water Distribution Utilities
Inlet and Outlet Water Pipe Pressure Measurement in Clean Water Systems
Clean water systems use lift stations and gravity feed reservoirs, to pump water between locations.
In some residential settings, lift stations and water towers alone cannot supply enough pressure, to provide users at higher elevations with clean water.
Also, water reservoirs and water towers, that experience sudden, large draws of water need replenishment.
Pressure-controlled variable frequency drive pumps (VFDs) are used with pressure transducers, for reliable electronic pressure measurement to determine when extra pressure and flow are required by users.
Pressure transducers are used to monitor water pressure, at elevation, in reservoirs, and the rate of change in each.
Of course, in the water supply or wastewater treatment industry, the measurement of water flow is also very important. For example, if you need to measure the flow of wastewater in a 2-inch pipe. Then you can refer to Magnetic Flow Meters Guides.
Electronic Pressure Transducer Applications for Water Pipe Pressure Measurement in Clean Water Systems
Pressure transducers are used for inlet and outlet water pipe pressure measurement, in clean water systems at public utilities.
An electronic pressure transducer is typically used in water distribution applications such as:
Pump intake pressure measurement
Pump output pressure measurement
End location (reservoir, elevated piping, etc.) pressure measurement
Pressure transducers are responsible for monitoring the pressure, at various locations throughout clean water systems and often interface with VFD pumps to show, when increased pressure or flow rates are necessary.
The SI-200 and SI-390 electronic pressure transducers are designed for long lifetimes, in both inlet and outlet pipes of clean water systems.
They can usually be delivered within days in a wide variety of configurations.
Submersible pressure transducer with 4-20mA output is Hydrostatic Level Sensor for level measurement. Submersible pressure transducer is based on the measured liquid static pressure proportional to the height of the liquid Principle. Convert static pressure into electrical signal. After temperature compensation and linear correction. Convert into standard electrical signal. Generally 4 ~ 20mA / 1 ~ 5VDC. It can also be called “static pressure liquid level gauge, liquid level transmission Device, liquid level sensor, water level sensor “. Bullet, cage, and flush tip models are available. Applications include pumps, downhole, oil tanks, lime slurry, and water tanks. There is a miniature submersible transmitter that is low power voltage.
SI-10 Liquid pressure sensor Liquid pressure sensor is widely used for pressure measurement of various liquids. Like water or oils. IP68 waterproof.
SMT3151TR Submersible Level Transmitter Hydrostatic level transmitter is also called hydrostatic level gauge. The rod-type Hydrostatic level transmitter 4-20mADC standard signal output. Flange or threaded installation. Can withstand high temperatures up to 450 ℃.
Extended Diaphragm Seal DP Level Transmitter Extended Diaphragm Seal DP Transmitter is a level transmitter direct mounted on pipe or tank. The isolation diaphragm is in direct contact with the liquid medium.
Differential pressure(DP) level transmitter Differential pressure (DP) level transmitter is a perfect solution for tank level measurement. Flanges, seal diaphragms, capillaries, and DP transmitter are often used to measure liquid levels.
The installation of the pressure transducer measurement system, consists of three parts, namely the laying of the pressure guiding tube, the laying of the electrical signal cable and the installation of the differential pressure transmitter. During the operation of the pressure transmitter, the pressure of the medium is transmitted to the central measuring diaphragm. Through the isolating diaphragm and the silicone oil, and the pressure difference from the double-sided pressure guiding tube is received on the double-sided isolating diaphragm, where the membrane is measured. The sheet functions as a resilient element and is deformed by the pressure difference. There is a positive proportional relationship, between the displacement of the measuring diaphragm and the differential pressure. And under the influence of the displacement of the diaphragm, the capacitance of the differential capacitor also changes. And the measuring circuit converts it into a DC current signal of 4-20 mA. Extended reading: Hydrostatic Pressure Transmitter
Where are pressure transducers used?
Pressure transducers are mainly used in the following areas: Petroleum, petrochemical, chemical. Matching with throttling devices to provide accurate flow measurement and control. Measures pressure and level in pipes and tanks. Electricity, city gas. And other companies and businesses require high stability and high precision measurement and other places. Pulp and papermaking are used in places that require chemical-resistant liquids and corrosion-resistant liquids. Steel, non-ferrous metals, and ceramics are used in furnace pressure measurement and other places that require high stability and high precision measurement. They are also used in places that require stable measurement under strict control (temperature, humidity, etc.). Machinery and shipbuilding, used to strictly control the place where high precision is required for stable measurement. Extended Reading: 4 wire pressure sensor wiring diagram
What is pressure sensor and how it works?
A pressure sensor is a device or device that can sense a pressure signal and convert the pressure signal into a usable output electrical signal according to a certain rule. A pressure sensor usually consists of a pressure-sensitive element and a signal processing unit. According to different test pressure types, pressure sensors can be divided into gauge pressure sensors, differential pressure sensors and absolute pressure sensors. A pressure sensor is the core part of pressure transmitter. More. Extended Reading: Wireless Water Meter
Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects.
Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.
A capacitive pressure transducer also called a Capacitance pressure transmitter or a Capacitance pressure sensor. The capacitive type pressure transmitter is a differential pressure type sensor.
What is the capacitive pressure transducer?
The capacitance pressure transmitter is a pressure measurement device, which converts an applied pressure into a current signal, Like 4-20mA.
A pressure transducer is a device that measures the pressure of a fluid, indicating the force the fluid is exerting on surfaces in contact with it.
Pressure transducers are used in many control and monitoring applications, such as flow, airspeed, level, pump systems, or altitude.
A pressure transducer consists of two main parts: an elastic material that will deform when exposed to a pressurized medium. And an electrical device that detects the deformation and converts it into a usable electrical signal.
The elastic material can be formed into many different shapes and sizes, depending on the sensing principle and range of pressures to be measured.
This often involves a diaphragm combined with an electrical device, that uses a resistive, capacitive, or inductive principle of operation.
A variable capacitance pressure transducer has a capacitive plate (diaphragm), and another capacitive plate (electrode) fixed to an unpressurized surface. With a gap of a certain distance between the diaphragm and the electrode.
A change in pressure will widen or narrow the gap between the two plates, which varies the capacitance.
This change in capacitance is then converted into a usable signal.
Capacitive Pressure Transducer Working Principle:
– A linear change in capacitance with changes in the physical position of the moving element, may be used to provide an electrical indication of the element’s position.
ε – Dielectric permittivity of the insulating medium
The permittivity of the medium and the area of overlapping will be constant in this case, the only varying parameter. In this case, is the distance between the conductors which varies when the pressure varies, which changes the capacitance.
So the pressure variation results in the capacitance variation. Our capacitance pressure sensor is shown below. Just like A Rosemount capacitance pressure sensor:
capacitance pressure sensor
Rosemount capacitance pressure sensor
The capacitance chamber is isolated from the process with an isolation chamber.
The pressure applied at one side. As the pressure at the high-pressure side increases the isolating diaphragm gets pushed toward the metal frame. Transferring its motion to the sensing diaphragm via the fill fluid.
The fill fluid will be oil.
A capacitance detector circuit connected to this cell uses a high-frequency AC excitation signal to measure the difference in capacitance between the two halves. Translating that into a DC signal ultimately becomes the signal output by the instrument representing pressure.
The simple capacitance detector connection with the electrical circuit is shown below:
A pressure transducer is a measuring device which converts an applied pressure into an electrical signal.
Generally, a pressure transducer consists of two parts, an elastic material that deforms under the application of pressure. And an electrical part which detects this deformation.
Absolute measurements are generally used in applications where you need a repeatable reference pressure; i.e. in an experiment or in a barometric application.
For example, if you are looking to replicate a test that was originally completed by a colleague in Denver, CO and you are at a facility in Boston.
May you may want to use an absolute sensor to minimize variables in your test.
Other applications include weather stations, altimeter calibration equipment, and semiconductor fabs and many more.
However, if you want to measure or control a pressure that is based on current conditions a gauge sensor may be best.
Generally, if you want to measure or control a pressure that is influenced by changes in atmospheric pressure.
This style sensor is used in any application where you want to overcome the atmospheric conditions, to produce a task or pull a vacuum to accomplisher another type of task.
The applications for gauge pressure sensors are quite vast.
Some examples are pump discharge pressure, fire hose discharge pressure, tank level, steam pressure in a commercial boiler and many more.
A sensor capable of compound pressure measurement is one that can measure both positive and negative (vacuum) pressures.
Often compound pressure ranges are utilized in applications, where different parts of a process may either be higher or lower than the atmosphere.
For example, if you were a manufacturer of a collapsible water bottle, in one part of the process you may pressurize a mold to form the bottle, but they pull a vacuum to release the part.
In this case, you may be able to use only one sensor instead of two to accomplish the same task.
Remember that Differential pressure is the difference in pressure between two points of measurement.
You can measure very low to high pressures in all kinds of different media including liquids, gases, water, refrigerants, and air.
Thus, if you want to measure the difference in pressure across a filter (see below), you could use a differential pressure transducer like 3151DP to tell you when it was time to change the filter.
So you can maintain the Indoor Air Quality (IAQ) of your building.
Differential applications can be quite varied, some examples supply and return pressure in a chiller, airflow stations, leak detection systems, pressurized tank level, hospital isolation or protection rooms, and many more.
SI-300 Pressure Transducer 4-20mA/Voltage The 4-20mA/ Voltage Pressure Transducer, also called pressure transmitter 4-20mA, is a pressure sensor with4-20ma/Voltage output.
SI-512H High Temperature Pressure Sensor High Temperature Pressure Sensor for pressure measurement of high temperature gas or liquid. Such as steam pressure. High temperature up to 800 ℃.
Hydrostatic pressure transmitter Hydrostatic pressure transmitter is used for fluid hydrostatic pressure measurement. With working static pressure up to 32Mpa, for liquid, gas or steam .
Diffused silicon Gauge Pressure Transmitter A gauge pressure (GP) transmitter compares a process pressure against local ambient air pressure. Gauge pressure transmitters have ports to sample the ambient air pressure in real-time.
Extended Diaphragm Seal DP Level Transmitter Extended Diaphragm Seal DP Transmitter is a level transmitter direct mounted on pipe or tank. The isolation diaphragm is in direct contact with the liquid medium.
Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects.
Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.
Pressure transmitters and transducers with industry-leading performance help improve operations in a wide range of industries
What is a pressure indicator transmitter?
Pressure indicator transmitters are industrial instruments, which has a digital display for providing a local indication of pressure indicating, and a 4-20 mA output pressure transmitter (which is also called the smart pressure gauge), for sending an analog signal to control & monitor instrumentation. The built-in digital indicators can be scaled via push buttons or change pots, to any pressure unit or a 0-100% full scaling. No additional external supply is required, since the digital indicator is powered by the 4-20mA current loop, from the pressure transmitter.
Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects.
Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.
Ultrasonic Level Transmitters & Ultrasonic Level Sensors are designed to provide accurate and reliable level sensing for difficult to monitor fluids, where contact with media is not desirable from the extremes of sending: ultrapure to corrosive or even dirty where coating or scaling is possible. Ultrasonic level transmitters have no moving parts, are easy to install and simple to use.
Ultrasonic level measurement provides continuous, non-contact and maintenance-free level measurement of fluids, pastes, sludges and powdery to coarse bulk materials. The measurement is unaffected by dielectric constant, density or humidity and also unaffected by build-up due to the self-cleaning effect of the sensors.
The basics of ultrasonic level transmitters – how they work and what they’re used for
Ultrasonic Level Transmitters working principle
The Ultrasonic Level Transmitter consists of three parts: ultrasonic transducer (probe), drive circuit (module), and electronic display module.
The Ultrasonic Sensor is installed on the storage tank or process vessel. The sensor sends out a sound wave, which ricochets off the surface of the liquid and returns to the sensor. The time it takes for the sound wave to travel from the sensor to the liquid surface and return to the sensor is measured. This time delay is proportional to the level of the liquid.
The drive circuit processes the signal from the Ultrasonic Sensor, compensates for adverse conditions (temperature, pressure, etc) and converts it into a standard 4-20mA or 0-5/10 Vdc signal that can be read by a PLC, DCS or Display/Transmitter.
The Display/Transmitter converts the 4-20mA or 0-5/10 Vdc signal into a display reading in the unit of measure required (feet, inches, meters, centimeters, etc). Ultrasonic level transmitters can be outfitted with local displays and push button controls for easy configuration without the need of a laptop or other computer.
Applications
Ultrasonic level transmitters are used for inventory management and process automation in a wide range of industries. Applications include:
The benefits of using an ultrasonic level transmitter
– Ultrasonic level transmitters are easy to install and simple to use.
– Ultrasonic level measurement provides continuous, non-contact and maintenance-free level measurement of fluids, pastes, sludges and powdery to coarse bulk materials.
– Ultrasonic level transmitters are unaffected by dielectric constant, density or humidity and also unaffected by build-up due to the self-cleaning effect of the sensors.
Sino-Inst offers a wide range of Ultrasonic Level Transmitters that can be used in various industries for inventory management and process automation. If you have any questions about which Ultrasonic Level Transmitter is right for your application, please contact us and we will be happy to assist you.
How to choose the right ultrasonic level transmitter for your needs
1. The ultrasonic level meter can only be used for the medium that can fully reflect sound waves and propagate sound waves. For the sound wave adsorption ability of the medium, it is not suitable to use ultrasonic level meter.
2. The ultrasonic level meter can not be applied to vacuum occasions, and not for negative pressure occasions. Because the propagation of ultrasonic waves need air medium. And the thin air environment is very unfavorable to ultrasonic propagation. Plus the sound attenuation will therefore increase. Ultimately, it will lead to serious errors in measurement or even can not be measured.
3. If the measured medium is a volatile liquid, or contains a large amount of water vapor, dust, bubbles, suspended particles and other media, the ultrasonic level meter should not be used. This is due to the fact that when the sound waves from the probe of the ultrasonic level meter encounter the above medium, irregular reflection and scattering will occur. The probe will not be able to receive the normal signal. And these media will absorb the sound waves. This causes the attenuation of sound waves and affects the measurement results.
4. If there are obstacles or equipment that affect the propagation of sound waves inside the vessel. Then the ultrasonic level meter is not recommended.
5. Ultrasonic level meter can generally only be applied in the normal temperature and pressure range. If the pressure is too high, it will have a strong inhibiting effect on the sound speed of the acoustic wave. Eventually, it will affect the measurement accuracy, or even impossible to measure. And the temperature generally cannot exceed 100℃.
Tips for ultrasonic level transmitter installation
Before installing the ultrasonic level Transmitters, please read the instruction manual of the ultrasonic level Transmitters carefully. Work according to the instructions.
At the same time, it should be reconfirmed whether the model of the instrument matches the environmental requirements of the site such as process pressure, process temperature, and chemical properties of the medium. To ensure that the instrument can be used normally after installation.
To install the ultrasonic level meter, please observe the following operating rules:
Try to avoid in-tank facilities such as ladders, heating equipment, limit switch brackets, etc. for installation.
The ultrasonic beam must not intersect the feed stream. At the same time, pay attention to ensure that the highest material level does not enter the measurement blind area during installation. The ultrasonic level Transmitters must not be installed above the feed stream.
When installing the ultrasonic level Transmitters, it should keep a certain distance from the tank wall. And keep the transducer perpendicular to the liquid surface as much as possible.
When installed outdoors, the ultrasonic level Transmitters should take sunshade and rainproof measures. To avoid direct sunlight and reduce measurement errors caused by temperature changes. At the same time should also pay attention to moisture.
The ultrasonic level Transmitters installed in the hazardous area must comply with the installation regulations of the national explosion-proof hazardous area. The intrinsically safe ultrasonic liquid level Transmitter is installed in the occasion with explosion-proof requirements, and the ultrasonic liquid level Transmitter must be grounded.
When there is stirring in the container. The ultrasonic level Transmitters should be kept away from the agitator. In order to eliminate the false echo effect produced by the stirring blade. If foam or waves are created due to agitation, the still-pipe installation method should be used.
When there is foam in the container. When feeding, stirring or doing other processing in the container, foam will be formed on the surface of some media, which will attenuate the signal of the ultrasonic level Transmitter. The sensor should be installed in a still-pipe or a guided-wave radar level Transmitters should be used. Guided wave radar level Transmitters measurements are not affected by foam and are ideal for this application.
When there is airflow in the container. If there is a strong airflow or air vortex in the container, or if it is installed outdoors and in a very windy place. The sensor should be installed in a still-pipe or a guided-wave radar level Transmitters should be used.
Depending on the shape of the tank top of the container, the installation position of the ultrasonic level transmitter should be selected to avoid multiple reflection echoes between the liquid level and the top wall. In order to reduce interference, reduce noise signal and ensure the accuracy of detection.
Installation position of ultrasonic level transmitters
The reasonable installation position of the ultrasonic level transmitter should be determined according to the different top and internal structure shapes of the liquid container:
A. Grooved container:
The support frame should be firm and reliable;
The height of the intersection line of the beam emitted by the probe and the tank wall must be less than or equal to the minimum height of the liquid level to be measured;
The installation height should be within the required range.
B. Arched container:
Meters cannot be installed on vaulted ceilings. It should be installed at 1/2 or 1/3 of the radius of the empowerment.
C. Conical container:
For conical containers with flat tops. The best place to install the meter is in the center of the top of the vessel. This ensures that you measure to the bottom of the container.
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Ultrasonic level transmitters use sound waves to measure the level of a liquid in a tank. The transmitter sends out a sound wave and measures the time it takes for the sound wave to bounce back. The transmitter then calculates the distance from the sensor to the liquid surface and displays the level on a digital display.
An ultrasonic level sensor is a device that uses sound waves to measure the level of liquids, pastes, sludges, and other similar substances. Ultrasonic sensors are unaffected by dielectric constant, density or humidity, and also have a self-cleaning effect that prevents build-up.
Ultrasonic level measurement works by sending out a sound wave from the sensor and measuring the time it takes for the sound wave to bounce back. The time it takes for the sound wave to bounce back is directly proportional to the level of the liquid. Ultrasonic sensors are very accurate and can be used in a wide range of applications.
Radar level transmitters use microwave energy to measure the level of liquids, while ultrasonic level transmitters use sound waves. Both technologies have their own advantages and disadvantages. Radar is more accurate than ultrasonic, but it is also more expensive. Ultrasonic is less accurate than radar, but it is less expensive and easier to install.
Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects.
Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.
A pressure transmitter also often called a pressure transducer. A pressure transmitter is a device used to measure the pressure of liquids or gases in pipes or containers. It works by converting the pressure readings into an electrical signal that can be easily transmitted to a control system for monitoring and analysis.
These devices are commonly used in industrial settings, such as in manufacturing plants and refineries. Where it’s important to monitor the pressure of gases and liquids flowing through pipes and containers to ensure that they’re at safe levels.
Pressure transmitters can measure pressure in gases, liquids, air or oil. Widely used in various industrial processes. Such as pharmaceutical industry, chemical feed, waste water industry, food industry, farms, etc.
Overall, pressure transmitters are essential tools for measuring and monitoring pressure levels in various settings, helping to keep people and equipment safe and functioning properly.
In order to choose a suitable pressure transmitter, we must understand what types of pressure transmitters are there, what are the functions of pressure transmitters, and how do pressure transmitters work? Read on to find out the answers below.
Types of Pressure Transmitters
According to different measurement media, pressure transmitters can be divided into liquid pressure transmitters and gas pressure transmitters. According to the measurement conditions, the pressure transmitter can have a high temperature type, a very low temperature type, and a high pressure type. Here we divide by the type of pressure measured.
Type of Pressure Transmitter
Characteristics/Principles
Absolute Pressure Transmitter
– Measures pressure relative to atmospheric pressure – Can only measure positive pressures
– Often called level transmitters. Because of their working principle and ability to measure level. – Hydrostatic pressure transmitters work on the basis that the amount of pressure increases with depth. – These devices are submersible and can be used for liquids and gases.
A pressure transmitter is a device that measures the pressure of fluids or gases in a process and converts it into an electrical signal that can be used for monitoring or control purposes. There are several different working principles that pressure transmitters use to accomplish this:
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.
Usually, the strain gauges are closely bonded to the substrate that generates mechanical strain with a special adhesive. When the stress of the substrate changes, the resistance strain gauge also deforms together. Change the resistance value of the strain gauge, so that the voltage applied to the resistance changes. The transmitter has extremely low price and high accuracy and good linearity characteristics.
Diffused silicon pressure transmitters were introduced in the mid-1990s. It utilizes the piezoresistive effect of elastic elements. When the pressure of the measured medium directly acts on the diaphragm of the sensor, the diaphragm produces a micro-displacement proportional to the pressure of the medium, which changes the resistance value of the sensor. This change is detected electronically. And convert and output a unified standard signal.
Compared with traditional products, this transmitter has the advantages of advanced technology, reliable performance, convenient installation, high accuracy and small size.
Corrosion-resistant ceramic pressure transmitters have no liquid transfer. When the pressure acts on the ceramic diaphragm, the diaphragm will produce a slight deformation. 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.
Therefore, it has high measurement accuracy, good stability, strong output signal and low price.
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.
The capacitive pressure transmitter is composed of a measuring diaphragm and electrodes on both sides of the insulating sheet to form a capacitance.
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.
It has 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.
There are three common signal outputs that pressure transmitters provide: millivolt, amplified voltage, and 4-20mA.
Below is a summary of the outputs and when they are best used.
Millivolt Output:
This type of output signal is a low-level voltage signal that is proportional to the pressure being measured. The signal typically ranges from 0-50mV or 0-100mV, depending on the specific pressure range being measured.
This type of output signal is usually used in applications where the signal needs to be amplified or converted to a different format before it can be used by the control system.
Amplified Voltage Output:
This type of output signal is a higher-level voltage signal that has been amplified to a specific range, such as 0-5V or 0-10V.
The voltage signal is proportional to the pressure being measured and can be used directly by the control system without the need for additional signal conditioning.
Amplified voltage output signals are commonly used in applications where the control system requires a voltage input signal.
4-20mA Output:
This type of output signal is a current signal that ranges from 4mA at zero pressure to 20mA at the maximum pressure being measured.
This type of signal output is popular because it is immune to electrical noise and can be transmitted over long distances without signal degradation.
4-20mA output signals are commonly used in industrial applications where the control system requires a current input signal.
The choice of signal output will depend on the specific requirements of the application, such as the distance between the pressure transmitter and the control system, the required accuracy and resolution, and the environmental conditions.
There are multiple types of pressure transducers for a variety of applications.
Each pressure transducer has different aspects, that will impact how it works and the applications the pressure transducer works best for.
When selecting a pressure transducer, keep these 6 criteria in mind:
Application and measurement type
Pressure range
Process media
Temperature range and installation environment
Accuracy
Output
If you still don’t know how to choose the pressure transmitter, please contact our sales engineers.
how to use a pressure transducer?
Once you receive the pressure transmitter you ordered, you are ready to use it. First, please check the instruction manual configured by the manufacturer. Based on our many years of experience at Sino-Inst, you can start using a pressure transmitter by following these steps:
Confirm parameters: Before use, please confirm whether the model, range, output type (generally 4-20 mA current output or 0-10 V voltage output) and working voltage of the pressure transmitter meet your application requirements.
Check the appearance: Carefully check whether the transmitter is physically damaged and whether the interface is clean.
Installation location: Install the pressure transmitter on the pipe or container that needs to be measured, ensuring that it is installed securely. Usually the pressure interface should be vertical to the ground.
Connect the power supply and output: According to the instructions of the pressure transmitter, connect the power cord and output cord. Current-type transmitters need to be connected in series in the control loop, and voltage-type transmitters need to be connected in parallel on the measuring equipment.
Zero point calibration: Perform zero point calibration in a no-pressure state to ensure that the output of the transmitter is 4 mA or 0 V when there is no load.
Testing and debugging: Turn on the power and gradually increase the pressure. Observe whether the output signal changes linearly with pressure. Adjust settings until the transmitter’s output meets operating requirements.
Record data: Record the output current or voltage value under different pressures. To ensure that the pressure transmitter can accurately reflect pressure changes throughout the entire working range.
Periodic calibration: Check and calibrate the pressure transmitter regularly to ensure its accuracy and stability in long-term operation.
Can a pressure transducer be used to measure volume?
Pressure transducer cannot be used to directly measure volume. Pressure transmitters are used to measure medium pressure.
However, we can also calculate the volume indirectly through measurements from a pressure transmitter. But this requires other parameters.
For example, in a closed tank, if the temperature of the gas can be kept constant. Then measuring the pressure of the gas can be used to calculate the volume of the gas. This is based on Boyle’s law, which states that the pressure of a gas is inversely proportional to its volume.
Or, in some liquid tanks, if the tank is regular, then we can calculate the cross-sectional area of the tank. Then by measuring the pressure at the bottom of the container, we can calculate the volume of the liquid. Our volumetric recorders also enable this conversion.
Different Types of Pressure have different characteristics. Different pressure transmitters bear different pressure types. Common pressure types include absolute pressure,…
Sino-Instoffers over 20 Pressure Transmitters. A wide variety of Pressure sensors options are available to you. Such as free samples, paid samples. Sino-Inst is a globally recognized manufacturer of Pressure sensors, located in China.
Sino-Inst sells through a mature distribution network that reaches all 30 countries worldwide. Pressure sensors products are most popular in Europe, Southeast Asia, and Mid East. You can ensure product safety by selecting from certified suppliers. With ISO9001, ISO14001 certification.
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Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects.
Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.
Pressure transmitter calibration is what you need to dobefore you install the pressure transmitters. Also called pressure transducer calibration, or pressure sensor calibration.
In this article, we will share pressure transmitter calibration using hart communicator.
Pressure transmitters used in the process industries are very durable and reliable instruments.
Even so, they still require periodic maintenance and calibration to ensure optimal performance.
Before we start to calibrate the pressure transmitter, we should know:
What is span in pressure transmitter?
Fig. showing span and zero adjustment
Span value: The difference between two minimum value and maximum value of readings is known as a span value.
As shown in fig. below span = 20mA – 4mA
Zero Value: The value of readings at zero lines (Y-axis) is known as zero value as shown in the figure.
How Often Should You Calibrate a Pressure Transmitter?
Pressure transmitters require regular maintenance and calibration to ensure optimum performance.
There are no specific rules for the calibration of pressure transmitters. However, this depends on the regulations the company must comply with and the purpose of the calibration. Examples include safety specifications, application requirements, process conditions or as part of standard maintenance.
General industry practice is to calibrate pressure transmitters every 1 to 3 years based on the above conditions.
If it is found that there are obvious errors, or it is more important, the calibration cycle can be shortened.
Once you have established the calibration interval and MPE, you are ready to perform the actual calibration procedure on your pressure transmitter.
The best-practice recommendation is:
Mount the transmitter in a stable fixture free from vibration or movement.
Exercise the sensor or membrane before performing the calibration.
This means applying pressure and raising the level to approximately 90 percent of the maximum range. For a 150 psi cell that means pressurizing it to 130–135 psig. Hold this pressure for 30 seconds, and then vent. Your overall results will be much better than if you calibrate “cold.” cent of the maximum range. For a 150 psi cell that means pressurizing it to 130–135 psig. Hold this pressure for 30 seconds, and then vent. Your overall results will be much better than if you calibrate “cold.”
Perform a position zero adjustment (zero the transmitter).
This is important because the orientation of the fixture used for calibration may be different than the way the transmitter is mounted in the process. Failing to correct for this by skipping this step can result in nonconformance. You may like: Magnetostrictive level transmitters Magnetostrictive level sensor
Begin the Pressure Transmitter Calibration procedure.
Typically this means three points up (0 percent/50 percent/100 percent) and then three points down. The 4–20 mA output should be 4 mA, 12 mA, and 20 mA at the three points (or the correct digital values for a smart transmitter). Each test point should be held and allowed to stabilize before proceeding to the next. Normally that should take no more than 30 seconds. You can use more points if you require higher confidence in the performance of the instrument.
Compare the results of your pressure transmitter to your reference device.
Document the results for your records.
Pressure transmitter calibration formula
There is a formula that we can easily use to convert most (or all) units utilizing 4 to 20 mA signal to mA units.
There are others out there but this is the simplest I know.
Below is a simple formula for pressure to current conversion.
For example:
the range is : 0 to 10 Bar
Full range = 10 Bar
Displayed or measured value: 7 Bar
15.2 mA is the equivalent current value of a 7 Bar pressure.
Apply 0% pressure as per LRV with handheld test pump and check multimeter if it is not 4ma adjust the zero pot in the transmitter and correct transmitter output to 4ma
Apply 100%pressure as per the URV and correct 20ma in multimeter by adjusting span pot in the transmitter
Repeat these steps to rectify the error.
In case of SMART Transmitter
We have to use HART communicator, connect the communicator with the transmitter select the HART Communicator Menu for lower range value trim and upper range value trim.
Basic Set up – Calibration – Zero Trim/Sensor Trim —Lower/Upper range value trims.
Take the transmitter on line. Ensure there is no leak
a small example of five-point calibration is given below
Low range value=0psi
upper range value=200psi
This calibration can work for Rosemount 3051 calibration.
Preparing for Field Calibration of Differential Pressure Transmitters
The usual practice is to disassemble the joint of the pressure guiding tube and the differential pressure transmitter, and then connect to the pressure source for calibration. It is troublesome and labor-intensive. The most worry is that there will be leakage or the pressure guiding pipe will be broken when disassembling and assembling the joint.
No matter what type of differential pressure transmitter, the positive and negative pressure chambers have exhaust, drain valves or cocks. This provides convenience for on-site calibration of the differential pressure transmitter, so that it can be calibrated without removing the pressure guiding tube. Differential pressure transmitter.
But make a fitting with the same thread as the vent, drain valve or cock.
When the differential pressure transmitter is calibrated, first close the positive and negative valves of the three-valve group. Open the balance valve, and then loosen the exhaust and drain valves to vent.
Then use a self-made connector to replace the vent, drain valve or cock connected to the positive pressure chamber. The negative pressure chamber is kept unscrewed, allowing it to vent to the atmosphere.
The pressure source is connected with the self-made joint through the rubber tube. Close the balance valve. And check the air circuit sealing.
Then connect the ammeter (voltmeter) and the hand-operated communicator into the differential pressure transmitter circuit, and start the calibration after power-on and preheating.
Field Calibration of Conventional Differential Pressure Transmitters
First adjust the damping to zero state, first adjust the zero point. Then add full pressure to adjust the full scale, so that the output is 20mA. The adjustment should be fast in the field. Here is a quick adjustment method for zero point and span.
When the zero point is adjusted, it has almost no effect on the full scale, but when the full scale is adjusted, it has an effect on the zero point. When there is no migration, the effect is about 1/5 of the range adjustment amount, that is, the range is adjusted upward by 1mA. The zero point will move upward by about 0.2mA ,vice versa.
E.g: The input full scale pressure is 100kPa, the reading is 19.900mA. The range-adjusting potentiometer makes the output 19.900+(20.000-19.900)×1.25=20.025mA, and the range increases by 0.125mA. Then the zero point increases by 1/5×0.125=0.025, and the zero-point potentiometer makes the output 20.000mA.
After the zero point and full scale adjustment are normal, check the middle scales, and make fine adjustments if they are out of tolerance. Then carry out the adjustment work of migration, linearity and damping.
Smart Differential Pressure Transmitter Field Calibration
The intelligent differential pressure transmitter is between the input pressure source and the output 4-20mA signal. In addition to machinery and circuits, there is also a microprocessor chip that operates on the input data.
Therefore, the field calibration method of intelligent differential pressure transmitter is different from that of conventional differential pressure transmitter.
The differential pressure liquid level transmitter has been calibrated according to customer requirements in terms of range, accuracy, linearity and other parameters. And mark the range, accuracy, etc. on the nameplate of the differential pressure liquid level transmitter. As long as the parameters such as the density of the measured medium meet the requirements of the nameplate, there is usually no need to adjust.
If the customer needs to adjust the span or zero position, please adjust according to the following methods. Assuming that the range of the differential pressure liquid level transmitter is 0~10 meters:
Unscrew the back cover of the differential pressure liquid level transmitter, connect an external standard 24VDC power supply and an ammeter (requires an accuracy of 0.2% or higher) to adjust.
When there is no liquid in the differential pressure liquid level transmitter. Adjust the zero point potentiometer so that the output current is 4mA.
Pressurize the differential pressure liquid level transmitter to the full scale (10 meters). Adjust the full-scale resistor so that the output current is 20mA.
Repeat the above steps two or three times until the signal is normal.
Please input 25%, 50% and 75% respectively to check the deviation of the differential pressure liquid level transmitter.
For non-water media, when the differential pressure liquid level transmitter is calibrated with water, it should be converted according to the pressure generated by the actual use of the medium density. For example, when the density of the medium is 1.3, the 1.3m water level should be used to calibrate the 1m range.
After adjustment, tighten the back cover.
The calibration cycle of the differential pressure liquid level transmitter is once a year.
The HART intelligent differential pressure liquid level transmitter of Sino-Inst can be selected, which is convenient to adjust the range of the differential pressure liquid level transmitter.
Learn more about Pressure Transmitter Calibration
When you buy a pressure transmitter, for example, you have the instrument range, which is the pressure range the device can support.
This range covers the overpressure that might occur in the device.
The measuring range covers the values where the transmitter works properly, omitting the overpressure zone.
The lower range limit (LRL) and upper range limit (URL) define this range.
Inside the measuring range, you’ll find the calibration span, the range in which your device will be working, depending on your application.
The calibration span covers the difference between your upper range value (URV), the maximum value your transmitter can read, and the lower range value (LRV), the minimum value the device can read.
So there you go!
You should also know that each instrument has a minimum and maximum calibration span it can support.
If you go below or over these limits, you’ll lose accuracy in your readings.
Make sense? Let me give you an example, just to make it clearer.
Let’s say you want a pressure transmitter with a measurement range of -100 to 200 kilopascals (kPa).
This device can measure pressures as low as -100 and as high as 200 kPa.
If your application just requires pressure between -20 to 50 kpa, then this will be your calibration range.
Your calibration span is the URV-LRV.
By the numbers: 50 – (-20) = 70 kPa.
Therefore, you get a calibration span of 70 kPa, which falls inside the span range (10 to 200 kPa).
A pressure transmitter or pressuresensor is a device that measures pressure in a liquid, fluid, or gas.
Pressure transmitters are commonly used to measure the pressure inside of industrial machinery, in order to alert the user before a catastrophe occurs.
Yes, pressure transducers require calibration. Pressure transducers are used in many applications to provide accurate, real-time data on how systems work. Calibration is critical to maintaining the accuracy of pressure sensors. And it’s not a one-time process.
If the sensor deviates from its specified pressure range, it may cause erroneous pressure readings. This results in degraded device performance and possible security issues.
Calibration allows users to be completely confident that their pressure transducers are performing correctly and accurately measuring the desired pressure range.
If you cannot find an answer to your question in our Pressure Transmitter Calibration you can always contact us and we will be with you shortly.
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Conclusion:
It is normal for the pressure transmitter to have a certain error. But if the error is too large, it needs to be calibrated. There are two types of Pressure Transmitter Calibrations: conventional method and intelligent calibration. no matter where Kinds of preparations must be done before calibration, and then calibrate and debug through the handheld operator.
There are no mandatory fixed requirements for Pressure Transmitter Calibration. Generally, enterprises can formulate them by themselves. Normally, they can be calibrated once a year. Crucially, the calibration cycle can be shortened.
About how to calibrate the pressure transmitter, and what needs to be paid attention to during the process of Pressure Transmitter Calibration. If you still have questions, please feel free to contact our engineers.
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Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects.
Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.