The relationship between volumetric flow rate of the turbine flowmeter and the frequency of the pulses generated by the pickup sensor can be expressed in the form of the equation:
f = kQ
Where, f = Frequency of pulses generated by pickup sensor(Hz, equivalent to pulses per second) Q = Volumetric flow rate (e.g. litres/min) k = “K” factor of the turbine meter (e.g. pulses per litre)
Turbine Meter K-Factor
The turbine meter measures volumetric flow, however the pulses produced vary depending on the meter. The variation is accounted for by a K-factor. The K-factor is the number of pulses per unit volume. It is primarily determined by the size and type of the turbine meter. Due to manufacturing tolerances, the actual K-factor can vary between similar models. The K-factor is applicable only to the fluid for which the meter was calibrated in the factory.
Output pulse frequency signal, suitable for total metering and connection with a computer, no zero drift, strong anti-interference ability.
Compact and lightweight, easy installation and maintenance, and large-circulation capacity.
Good repeatability, short-term repeatability of 0.05 ~ 0.2%, due to good repeatability, frequent calibration or online calibration can get very high precision.
A special type of sensor can be designed according to user needs, such as low-temperature type, two-way, downhole type, mixed sand special type.
Pressure compensation can be performed under the pressure state in which the gas to be measured is stable.
The turndown is wide, medium and large caliber up to 1:20, small-caliber is 1:10.
Disadvantages of Turbine Flow Meters
Need to be calibrated regularly, there is no way to maintain accuracy for a long time, can not work continuously for a long time.
The cleaning requirements of the medium are high, but the filter can be installed.
The flowmeter has a large influence on the flow velocity distribution (flow regulator can be installed).
It is not suitable for places where the flow rate is drastically changing.
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.
A differential pressure transmitter is used to measure pressure before and after the cone.
This type of differential pressure flow meter can be constructed to measure gases, liquids, or steam.
This type of flow meter relates a change in flow rate to the differential pressure across a spring-loaded cone.
The cone repositions itself to balance the force.
This, in turn, changes the aperture for the flow.
Flow rate has a relationship with the differential pressure of the flow meter and the position of the spring-loaded cone.
A differential pressure transmitter is used to indicate flow.
This type of differential pressure flow meter technology can be constructed to measure either gas or liquids.
Flow rate is linearly proportional to the differential pressure and inversely proportional to the viscosity of the flowing fluid.
A flow can be made laminar by passing through a bundle of small diameter tubes.
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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.
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 ℃.
Absolute Pressure Transmitter Absolute pressure transmitter with 4-20mA output for measuring pressure with absolute type reference. Absolute pressure (AP) transmitter is a measure of the ideal (complete) vacuum pressure.
Hydrostatic pressure transmitter Hydrostatic pressure transmitter is used for fluid hydrostatic pressure measurement. With working static pressure up to 32Mpa, for liquid, gas or steam .
Diffused silicon Gauge Pressure Transmitter A gauge pressure (GP) transmitter compares a process pressure against local ambient air pressure. Gauge pressure transmitters have ports to sample the ambient air pressure in real-time.
Capacitive Gauge Pressure Transmitter Gauge pressure (GP) transmitters compare process pressure with local ambient air pressure. Gauge pressure transmitters have ports for real-time sampling of ambient air pressure.
Extended Diaphragm Seal DP Level Transmitter Extended Diaphragm Seal DP Transmitter is a level transmitter direct mounted on pipe or tank. The isolation diaphragm is in direct contact with the liquid medium.
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.
In this article, you will learn what a HART protocol is,
how HART is used with analog sensors,
how a HART analog sensor works,
and what advantages a HART analog sensor can give your operation.
HART (Highway Addressable Remote Transducer) Protocol is an open standard,used globally to send and receive digital information,using analog wiring between smart devices and control systems. With over 30 million devices installed, it is the most popular protocol used in the field.
What is the HART protocol?
HART was first available in the late 1980s, and quickly gained in popularity, mainly due to its ability to continue to support the older 4-20 mA analog protocol, while adding the significant benefits of digital smart instrumentation.
The HART Protocol is based on the Bell 202 Standard, to superimpose digital information on the conventional 4-20 mA analog signal. Maintained by an independent organization, the HART Communication Foundation, the HART protocol is an industry-standard developed to define the communications protocol, between intelligent field devices and a control system.
The HART Protocol defines physical connection technology, as well as commands used by applications. There are three classes of HART commands: 1) Universal, 2) Common Practice, 3) Device-Specific.
HART protocol
Universal commands are required to be implemented by all HART devices. They are primarily used by a controller to identify a field device and read process data.
Common Practice commands define functions that are generally applicable only to field devices. These include commands to change the range, select engineering units and perform self-tests.
The third set of commands, Device Specific, are different for each device. Device-Specific commands implement unique configuration and adjustment functions.
The HART Protocol makes uses Frequency Shift Keying (FSK)，standard to superimpose digital communication signals，at a low level on top of the 4-20mA.
This enables two-way field communication to take place，and makes it possible for additional information，beyond just the normal process variable to be communicated to/from a smart field instrument.
,hart protocol how it worksHART protocolhart technologyhart communicationhart application
The HART Protocol communicates at 1200 bps， without interrupting the 4-20mA signal, and allows a host application (master), to get two or more digital updates per second from a smart field device.
As the digital FSK signal is phase continuous, there is no interference with the 4-20mA signal.
The HART Protocol provides two simultaneous communication channels: the 4-20mA analog signal and a digital signal.
The 4-20mA signal communicates the primary measured value (in the case of a field instrument) using the 4-20mA current loop – the fastest and most reliable industry standard.
Additional device information is communicated, using a digital signal that is superimposed on the analog signal.
The digital signal contains information,
from the device including device status, diagnostics,
additional measured or calculated values, etc.
Together, the two communication channels provide a low-cost,
and very robust complete field communication solution,
that is easy to use and configure.
HART Communication occurs between two HART-enabled devices,
typically a smart field device and a control or monitoring system.
Communication occurs using standard instrumentation grade wire and using standard wiring and termination practices.
The digital signal contains information,
from the device including device status, diagnostics,
additional measured or calculated values, etc.
HART technology is a master/slave protocol,
which means that a smart field (slave) device only speaks when spoken to by a master.
The HART Protocol can be used in various modes，
such as point-to-point or multidrop，
for communicating information to/from smart field instruments ，
and central control or monitoring systems.
The HART Protocol provides for up to two masters (primary and secondary). This allows secondary masters, such as handheld communicators to be used, without interfering with communications to/from the primary master, i.e. control/monitoring system.
The HART Protocol permits all digital communication with field devices, in either point-to-point or multidrop network configurations:
There is also an optional “burst” communication mode, where a single slave device can continuously broadcast a standard HART reply message. Higher update rates are possible with this optional burst communication mode, and use is normally restricted to point-to-point configuration.
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.
Magmeter is a volumetric flow meter that measures the flow of conductive fluid in a closed pipeline. Magmeter is also called electromagnetic flow meter, magnetic flow sensor, magnetic flow meter, etc. Magmeters is based on electromagnetic induction technology and outputs 4-20mA and other signals. Used in wastewater treatment, sewage treatment, chemical plants, etc.
First, let us look at the structure of the magmeter.
The structure of electromagnetic flowmeter is mainly composed of magnetic circuit system, measuring catheter, electrode, shell, lining and converter.
Magnetic flow meter principle
The electromagnetic flowmeter is made according to Faraday’s law of electromagnetic induction. It is used to measure the volume flow of conductive liquid.
Faraday’s law of induction (referring to the induction of an electric potential inside the conductor when the conductor passes through a magnetic field) is the basic principle of electromagnetic flowmeter measurement.
This measurement principle can be applied to conductive fluids.
The fluid flows into a pipe whose magnetic field is perpendicular to the direction of the fluid, and the electric potential induced in the fluid can be measured using two symmetrically arranged electrodes.
The signal voltage UE is proportional to the magnetic induction intensity B, the electrode spacing D and the average fluid velocity v.
Because the magnetic induction intensity B and the electrode spacing D are constant. Therefore, the signal voltage UE is proportional to the average flow velocity v.
The equation used to calculate the volume flow rate shows that the signal voltage UE is linearly proportional to the volume flow rate.
The sensed signal voltage is converted into the graduation in the converter, analog and digital output signals.
Magmeter flowmeters measure the velocity of conductive liquids (such as water, acid, caustic and slurry) in the pipeline. When measuring deionized water, the minimum conductivity of the medium is 20uS/cm. For most liquids, the minimum conductivity required for measurement can be 5uS/cm.
Magmeter is mainly used in the following areas:
Measure clean water, sewage, domestic water, raw water;
Various acid, alkali, salt and other solutions;
Mud, mineral pulp, paper pulp, and food liquids, etc.;
It is widely used in metallurgy, papermaking, water treatment, chemical industry, light industry, textile, food and beverage, catering, agricultural irrigation, hydropower station, oil production, electric power and mining industries.
Magmeter liner selection should be selected according to the corrosiveness, abrasiveness and temperature of the measured medium.
Hard/soft rubber is resistant to general weak acid and alkali corrosion. Temperature resistance is 65℃. Soft rubber has abrasion resistance.
Polytetrafluoroethylene (PTFE) is almost resistant to strong acid and alkali corrosion except hot phosphoric acid. The temperature of the medium can reach 130℃. But it is not resistant to wear.
Polyurethane rubber has good wear resistance. But it is not resistant to acid and alkali corrosion. Temperature resistance is also poor. The medium temperature is less than 65°C.
Liner Materials
Functions
Applications
Hard rubber
1. It is resistant to hydrochloric acid, acetic acid, oxalic acid, ammonia, phosphoric acid and 50% sulfuric acid, sodium hydroxide, and potassium hydroxide at room temperature. 2. Avoid strong oxidants.
1, below 70℃ 2. General acid, alkali, and salt solutions.
Soft rubber
1. It has good elasticity and good wear resistance; 2. It is resistant to the corrosion of general low-concentration acids, alkalis, and salt media, and is not resistant to the corrosion of oxidizing media.
1. The material with the most stable chemical properties in plastics. It can withstand boiling hydrochloric acid, sulfuric acid, nitric acid and aqua regia, as well as strong alkalis and various organic solvents; 2. Poor abrasion resistance and adhesion.
1.-40℃~+130℃C(PTFE), -40℃~+160℃(PFA); 2. Strong corrosive media such as acid and alkali; 3. Sanitary media.
PO
1. It can withstand hydrochloric acid, acetic acid, oxalic acid, ammonia, phosphoric acid, sulfuric acid, sodium hydroxide, and potassium hydroxide at room temperature. 2. It can withstand concentrated alkali and various organic solvents.
1. Below 70℃; 2. General acid, alkali, and salt solutions; 3. General water, sewage, mud, mineral slurry.
Ceramics
Wear resistance, high temperature resistance, corrosion resistance
Below 200℃
1.Environmental conditions:
Magmeter flowmeter, especially the flowmeter with intelligent LCD screen. The installation position should avoid direct sunlight as much as possible. The ambient temperature should be between 5℃~55℃.
2.Avoid strong interference sources
Choose a place where there is no strong electromagnetic field radiation to install the flowmeter.
Avoid devices that can easily cause electromagnetic interference, such as motors, transformers, and frequency converters.
The measurement principle of the flowmeter is based on Faraday’s law of electromagnetic induction, the original The initial signal is very weak, less than millivolt.
If there is strong electromagnetic field radiation near the flowmeter, it will affect the accuracy of the measurement and even fail to work normally.
3.Magmeter straight run
Pay attention to avoid eddy current generating parts as much as possible. Such as various valves, elbows, bypasses, etc.
Try to extend the straight pipe section upstream and downstream of the flowmeter. Install a rectifier tube if necessary.
Ensure that the upstream straight pipe section of the flowmeter must be at least 5 DN (measurement pipe diameter). The downstream is guaranteed to be more than 2 DN.
4.The conductivity of the liquid must be uniform and stable
Do not install the flowmeter in a place where the conductivity of the fluid to be measured is extremely uneven. If different media are injected upstream, the conductivity will be uneven and will affect the measurement.
In this case, it is recommended to move the injection port downstream.
If it must be injected from upstream, it should be as far away from the flowmeter as possible. Generally, it is better to keep a distance of more than 20 DN. To ensure that the liquid is fully mixed and uniform.
5.Keep the electrode axis level
The plane of the intermittent measuring electrode must be kept level. This prevents short-term insulation between the two electrodes due to air bubbles.
6.Magmeter grounding rings
Since the induction signal of the electromagnetic flowmeter is very weak, it is susceptible to noise. Therefore, the reference potential of the sensor and the converter must be the same as the measured liquid, and be grounded together.
The purpose of installing grounding rings or grounding electrodes on both sides of the electromagnetic flowmeter is to establish the equipotentiality between the flowmeter casing and the liquid.
Ordinary metal pipe (generally no need to install grounding ring)
When the pipeline itself is well grounded, the grounding wire can be omitted, but the casing must be connected to the liquid through the grounding wire equipped with the flowmeter.
A grounding ring (or grounding electrode) should be installed at both ends of the sensor and the measured medium should be short-circuited with the earth through the grounding wire.
Cathodic protection pipeline
The pipe flanges are connected by copper wires, but they must be insulated from the grounding wire.
Magnetic flowmeter is a widely used flow measuring instrument. How should we calibrate it?
Let’s take a look at the calibration method of electromagnetic flowmeter:
Determine the corresponding water pump according to the pipe diameter and flow rate of the verification test;
After the flowmeter is correctly installed and connected, it should be energized and preheated for about 30 minutes in accordance with the requirements of the verification regulations;
If the high-level tank water source is used, check whether the overflow signal of the stabilized water tower appears. Before the formal test, use the verification medium to circulate in the pipeline system for a certain period of time. At the same time, check whether there is any leakage in the sealing parts of the pipeline;
The verification medium should be filled with the electromagnetic flowmeter sensor before the formal verification. Then the downstream valve should be closed to adjust the zero position;
At the beginning of the verification, open the valve at the front of the pipeline and slowly open the valve behind the electromagnetic flowmeter to adjust the flow at the verification point.
During the calibration process, the flow stability of each flow point should be within 1% to 2%-flow method. The total amount law can be within 5%.
The temperature change of the verification medium should not exceed 1℃ when the verification process of a flow point is completed. It should not exceed 5℃ when the entire verification process is completed.
There must be a sufficiently high pressure downstream of the electromagnetic flowmeter to be checked to ensure that no flashing and cavitation occur in the flow pipeline;
After the test, close the valve at the front end of the test pipeline. Then stop the pump to avoid emptying the voltage stabilization facility. At the same time, the remaining verification medium in the test pipeline must be vented and the control system and the air compressor must be closed.
A Rotameter flow meter is a variable area flow meter based on float position measurement. It is suitable for liquid and gas volumetric flow measurement and control.
All electromagnetic flowmeters need to be calibrated when they leave the factory. Each finished product needs to pass the calibration line inspection before leaving the factory.
It is to install the product on the assembly line. The front end adopts a strictly debugged standard table. A series of coefficients such as the diameter of the flowmeter, the damping coefficient, and the sensor coefficient of the electromagnetic flowmeter are set at the back end. To achieve the same flow rate as the standard meter.
If calibration is done on-site, it may generally be used to calibrate outside the sealed pipeline. Such as portable ultrasonic flowmeter. But the accuracy is generally 0.5. If you just check it, you can use a portable ultrasonic flowmeter.
Ultrasonic flow meters and electromagnetic flow meters have different measurement principles.
Electromagnetic flowmeter must measure conductive liquid. The ultrasonic flowmeter can measure pure single-phase liquid. It has nothing to do with the conductivity of the liquid.
The electromagnetic flowmeter must be in contact with the medium to measure. The ultrasonic flowmeter can do contact and non-contact measurement.
The electromagnetic flowmeter is a flow measuring instrument. The measuring principle of the electromagnetic flowmeter is measured according to its principle of conduction. Most of the flow measurement on the market is solved by electromagnetic flowmeters.
The electromagnetic flowmeter is a pure liquid volume measurement instrument.
The mass flow meter is a function of fluid volume and fluid temperature and pressure. Is a dependent variable. The quality of a fluid is a quantity that does not change with time, space temperature, and pressure.
Mass flow meters are compared with electromagnetic flow meters. It can measure non-conductive media. This is one of the biggest differences. In addition, the accuracy of the mass flow meter is higher. The cost is large, and there are fewer applications in the market.
There is a big difference in the performance of general-purpose electromagnetic flowmeters on the market. Some have high precision and many functions. Some have low precision and simple functions.
The basic error of the instrument with high accuracy is (±0.5%～±1%)R. The instrument with low accuracy is (±1.5%～±2.5%)FS. The price difference between the two is 1 to 2 times.
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Magnetic flow meter manufacturers
Sino-Inst is one of the reliable Magnetic flow meter manufacturers and suppliers in China. Magnetic flow meters apply for wastewater flow rate measurement.
Sino-Inst can offer stainless steel magnetic flow meters, both the Pipeline and plug-in style. Of course, Sino-Inst can offer you with the mass flow meters and other flow meters.
Sino-Inst will offer you Magnetic flow meters with the Best Price. Reference price, $300-400/piece, DN10-DN2000. For special measuring media, we offer special lining materials: F4, F46, Fs, neoprene, urethane rubber, etc.
Sino-Inst offer over 20 Magnetic flow meters, with Best Price. A wide variety of Magmeters options are available to you, such as free samples, paid samples.
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.
Turbine Flow Meters have always been popular. Especially for measuring various liquids, such as water, diesel oil, ethanol, etc. Of course, gas turbine flowmeters are becoming more and more widely used in natural gas and other measurement applications. It is very important for you to find a suitable and reliable Turbine Flow Meter manufacturer. Not only the price! What’s more important is the ability to customize the turbine flowmeter for your specific flow application!
Sino-Inst, as a turbine flow meter manufacturer, provides high-performance liquid and gas turbine flow meters in various materials and accuracy. durable. Provides the performance needed to ensure optimal measurements.
A turbine flow meter is a type of flow meter that works by measuring the velocity of a fluid or gas as it passes through a turbine rotor. Turbine flow meters are commonly used to measure the flow of liquids and gases in a wide range of applications. They offer a high level of accuracy, especially in high flow rate applications, and can be used for both clean and dirty fluids. Turbine flow meters are also relatively easy to install and maintain, making them a popular choice in many industries.
Turbine flowmeter is composed of turbine, bearing, preamplifier and display instrument.
The principle of the turbine flowmeter is to place a turbine in the center of the pipeline, and the two ends are supported by bearings. As the fluid passes through the pipes, it strikes the turbine blades. Drive torque to the turbine. Make the turbine rotate by overcoming the friction torque and fluid resistance torque.
In a certain flow range, for a certain fluid medium viscosity, the rotational angular velocity of the turbine is proportional to the fluid velocity. Thus, the fluid flow rate can be obtained from the rotational angular velocity of the turbine, so that the fluid flow through the pipeline can be calculated.
The fluid to be measured impacts the turbine blades, causing the turbine to rotate, and the rotation speed of the turbine changes with the change of the flow rate. That is, the flow rate is large, and the speed of the turbine is also large. Then the rotation speed of the turbine is converted into electric pulses of corresponding frequency by the magnetoelectric conversion device. After being amplified by the preamplifier, it is sent to the display instrument for counting and display. According to the pulse number and cumulative pulse number per unit time, the instantaneous flow and cumulative flow can be calculated.
Turbine flow meters offer a number of advantages over other types of flow meters. Here are some of the key benefits of using turbine flow meters:
High accuracy: Turbine flow meters offer a high level of accuracy, especially in high flow rate applications. They have an accuracy of ±0.5% to ±1.0% of reading.
Wide flow range: Turbine flow meters have a wide flow range capability. They can measure flow rates from as low as 0.1 GPM (gallons per minute) to as high as 10,000 GPM, depending on the model and size.
Quick response time: Turbine flow meters have a fast dynamic response time, which means that they can measure changes in flow rate quickly.
Versatile: Turbine flow meters can be used to measure the flow of a wide range of fluids and gases. Including hydrocarbons, chemicals, water, cryogenic liquids, air, natural gas, and industrial gases.
Overall, turbine flow meters are a reliable and cost-effective method for achieving high accuracy flow measurement.
No, a rotary meter is a different type of flow meter than a turbine meter. While both are used to measure the flow of liquids or gases, they operate on different principles and have distinct designs.
A rotary meter, also known as a positive displacement meter, works by dividing the fluid or gas being measured into specific volumes and then counting the number of volumes that pass through the meter.
In contrast, a turbine flow meter works by measuring the velocity of the fluid or gas as it passes through a turbine rotor. The rotor spins at a speed proportional to the flow rate, and this motion generates an electrical signal that can be used to measure the flow rate.
While both types of flow meters are used for measuring the flow of liquids or gases, they are different in their operation and design.
As Manufacturer- We Can Offer
Extensive customization services:
Product brand OEM
Product parameters customization:
Temperature, high temperature or low temperature liquid (liquid nitrogen, liquid oxygen, etc.);
Pressure, especially high pressure products, 16MPa, 25MPa, 32MPa, etc.;
Connecting flange: Accept flange thread customization such as German standard DIN, American standard ANSI, and Japanese standard JIS.
Last but not least. We can offer you the most reasonable price. The cheapest price is not necessarily the best product. Reference: DN50 Turbine Flow Meter Price, FOB Price USD 298.00/set
Sino-Inst offers a variety of hydraulic oil flow Meters for…
Sino-Inst is one of the most reliable Turbine flow meter manufacturer and supplier in China. A turbine flow meter measures volumetric fluid flow in a closed pipe. Turbine flow meters measure the flow rate of liquids, gases and vapors in pipes, such as natural gas, chemicals, water, cryogenic liquids, air, and industrial gases. Digital turbine flow meters can work as the eletromagnetic flow meters, and mass flow meter, for the inline flow measurement. But the turbine flow meter accuracy is the highest.
Sino-Instrument is the risk-free choice for your flow measurement applications.
Sino-Inst ’s turbine flow meters, made in China. Having good Quality, With better price. Our flow measurement instruments are widely used in China, India, Pakistan, US, and other countries.
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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.
