Flowt Automation Equipment (Shenzhen) Co.,Ltd.：Your Trustworthy Thermal Mass Flow Meter Manufacturer！
Our Company is established by flow measurement professionals with more than 20 years of experience in flow measurement and flow standards. We are pioneers in the ultrasonic flow measurement industry and possess many years of experience valuable to our customers. Furthermore, We are innovative and on the cutting edge of ultrasonic technology with some revolutionary measurement techniques being introduced that will bring very high precision and true real time measurement.
Leading Service
We are committed to constantly innovating our products to provide foreign customers with a large number of high-quality products to exceed customer satisfaction. We can also provide customized services according to customers' requirements such as size, color, appearance, etc. We can provide the most favorable price and high-quality products.
Quality Guaranteed
We have been continuously researching and innovating to meet the needs of different customers. At the same time, we always adhere to strict quality control to ensure that the quality of every product meets international standards.
Wide Sales Countries
Our products have been exported to more than 40 countries, such as Russia, Australia, USA, UK, Germany, Ukraine, Iran, Romania, Hungary, Mexico, Brazil, Chile, Canada, Spain, Colombia, etc. We have agents in the USA, Australia, Singapore, Kuwait, Russia.
Various Types of Products
Our products include a wide range of flow meter like Ultrasonic Flow Meter，Electromagnetic Flow Meter, Vortex Flow Meter, Thermal Mass Flow Meter, Turbine Flow Meter, Liquid Level Flow Meter, Gear Flow Meter, Totalizer Flow Meter and so on.
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Mass Air Flow Meter1.Apply high stability and patented technology platinum RTD sensor 2. Proprietary algorithms; can achieve high linearity, high repeatability, high precision. 3. Range ratio 1000:1, also can be -
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Thermal Flow Meter SupplierVF10 thermal gas mass flow meter is a instrument that uses heat conduction theory to measure fluid flow. This instrument adopts method of differential constant temperature to accurately measure gas -
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Air Mass Flow MeterThermal flowmeters are most commonly used to measure the mass flow of clean gases, such as air, nitrogen, hydrogen, helium, ammonia, argon, and other industrial gases. Mixtures, such as flue stack -
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Gas Mass Flow MeterThe VF10T thermal mass flow meter works on the principle of thermal dispersion and determines the standard volumetric or gas mass flow. The readings are unaffected by pressure and temperature -
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Gas Mass Flow Meter Air Flow MeasureOur Thermal Mass Flow Meters operate using a constant temperature system that employs two RTD sensors; one for sensing temperature, and one for sensing flow. The sensor is heated to a precise -
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Thermal Flow Meter Air MeterIn most industrial facilities Compressed Dry Air is a primary component of overall energy use. In fact, compressed air is considered to be the “fourth utility” after electricity, natural gas and -
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Good Quality Thermal Mass Flow MeterGood quality thermal mass flow meter with high accuracy for gas measurement VF serial is a promoter of thermal mass flow meter in the field of industrial application, and is constantly committed to -
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Thermal Mass Air Flow Meter Application in Air MeasurementThermal mass air flow meter application in air measurement VF10 thermal mass flow meter is based on the technology of thermal diffusion, and does not need temperature and pressure compensation in -
![Thermal Mass Flow Meter for Measuring Gas with Stable Performance]()
Thermal Mass Flow Meter for Measuring Gas with Stable PerformanceThermal mass flow meter for measuring gas with stable performance VF10 series thermal mass flow meter is an instrument that uses heat conduction theory to measure fluid flow. This instrument adopts -
![Insertion Type Thermal Mass Flow Meter Application in Oxygen or Air]()
Insertion Type Thermal Mass Flow Meter Application in Oxygen or AirInsertion type thermal mass flow meter application in gas VF serial thermal mass flow meter widely application in the following: 1. Measuring Compressed Air 2. Measuring Boiler Combustion/Natural Gas
What Is Thermal Mass Flow Meter?
A thermal mass flow meter is a precision instrument that measures gas flow entirely differently, eliminating the need for pressure and temperature correction. Thermal mass flow meters measure the heat transfer as the gas flows past a heated surface. The gas molecules create the heat transfer, so the greater the number of gas molecules in contact with the heated surface, the greater the heat transfer. Thus, this method of flow measurement is dependent only on the number of gas molecules and is independent of the gas pressure and temperature.
Thermal Mass Flow Meter Benefits
Low Maintenance
Thermal flow meters do not have any moving parts. The compact design reduces the maintenance requirements and allows thermal mass flow meters to function in even the most demanding application environments, including those with saturated gas.
Measure Mass Flow
Thermal mass flow meters are designed to calculate the mass flow rather than the volumetric flow. This is beneficial in many applications because it removes the need for temperature or pressure correction. It also reduces the need for additional equipment.
Versatile
There are many different types of thermal mass flow meters. Many devices are available in both insertion and inline styles. Unlike some measurement tools, thermal mass flow meters can be used to measure gases in large pipes.
Accurate and Reliable
Thermal mass flow meters provide excellent accuracy and reliability across a wide range of applications and flow rates. The repeatability rates are also impressive at a margin of error of ±0.2% of full scale.
Types of Thermal Mass Flow Meter
Heated Tube Design
Heated tube flow meters were developed to protect the heater and sensor elements from corrosion and any coating effects of the process. By mounting the sensors externally to the piping, the sensing elements respond more slowly, and the relationship between mass flow and temperature differences become nonlinear. This nonlinearity results from the fact that the heat introduced is distributed over some portion of the pipe's surface and transferred to the process fluid at different rates along the length of the pipe.
The pipe wall temperature is highest near the heater, while, some distance away, there is no difference between wall and fluid temperature. Therefore, the temperature of the unheated fluid (Tf) can be detected by measuring the wall temperature at this location further away from the heater. This heat transfer process is non-linear, and the corresponding equation differs from the one above as follows: m0.8 = Kq/(Cp(Tw – Tf)).
This flow meter has two operating modes: one measures the mass flow by keeping the electric power input constant and detecting the temperature rise. The other mode holds the temperature difference constant and measures the amount of electricity needed to maintain it. This second mode of operation provides for a much higher meter rangeability.
Bypass-Type Design
The bypass version of the thermal mass flow meter was developed to measure larger flow rates. It consists of a thin-walled capillary tube (approximately 0.125 in diameter) and two externally wound self-heating resistance temperature detectors (RTDs) that both heat the tube and measure the resulting temperature rise. The sensor is placed in a bypass around a restriction in the main pipe and is sized to operate in the laminar flow region over its full operating range.
When there is no flow, the heaters raise the bypass-tube temperature to approximately 160°F above ambient temperature. Under this condition, a symmetrical temperature distribution exists along the length of the tube. When flow is taking place, the gas molecules carry the heat downstream, and the temperature profile is shifted in the direction of the flow. A Wheatstone bridge connected to the sensor terminals converts the electrical signal into a mass flow rate proportional to the change in temperature.
The small size of the bypass tube makes it possible to minimize electric power consumption and to increase the speed of response of the measurement. n the other hand, because of the small size, filters are necessary to prevent plugging. One serious limitation is the high-pressure drop (up to 45 psi) needed to develop laminar flow. This is typically acceptable only for high-pressure gas applications where the pressure needs to be reduced in any case.
This is a low accuracy (2% full scale), low maintenance, and low-cost flow meter. Electronic packages within the units allow for data acquisition, chart recording, and computer interfacing. These devices are popular in the semiconductor processing industry. Modern day units are also available as complete control loops, including a controller and automatic control valve.
Air Velocity Probes
Probe-style mass flow sensors are used to measure air flows and are insensitive to the presence of moderate amounts of dust. They maintain a temperature differential between two RTDs mounted on the sensor tube. The upper sensor measures the ambient temperature of the gas and continuously maintains the second RTD (near the tip of the probe) at 60°F above ambient. The higher the gas velocity, the more current is required to maintain the temperature differential.
Another version of the velocity probe is the venturi-type thermal mass flow meter, which places a heated mass flow sensor at the minimum diameter of a venturi flow element and a temperature compensation probe downstream. An inlet screen mixes the flow to make the temperature uniform. This design is used for both gas and liquid measurement (including slurries), with flow range a function of the size of the venturi. Pressure drop is relatively low, and precision is dependent upon finding the proper probe insertion depth.
A flow switch version is also available that contains two temperature sensors in the tip. One of the sensors is heated and the temperature difference is a measure of velocity. The switch can be used to detect high or low flow within 5%.
Working Principle of Thermal Mass Flow Meter
The Constant Temperature Method
There are two basic ways for a thermal mass flowmeter to function. The first is the constant temperature method. Flowmeters that operate with this method use two matched resistance temperature detectors (RTDs), one passive and one active, as a sensor element. The RTDs work in tandem, with one operating as a temperature reference and the other operating as a heat sensor. When the RTDs come in contact with moving gas molecules, the active heat sensing RTD measures the temperature of the gas. This reading is measured against the passive, heated RTD. The mass flow rate is then calculated based on the amount of energy needed to maintain a constant temperature difference between the two RTDs.
The Constant Power Method
The second method a thermal mass flowmeter can use is called the constant power method. This method uses a sensor with three active elements. Like the constant temperature method, the constant power method uses one heated RTD to sense to serve as a temperature reference, and one active RTD that senses the temperature of moving gas molecules. Unlike the constant temperature method, the constant power method also uses a constant current heating element, which is coupled to the passive RTD. A constant amount of power is delivered to the heated RTD. The mass flow rate is calculated by the temperature difference between the heated RTD and the flow stream.
Though thermal mass flowmeters that use the constant temperature method are more widely used than those that use the constant power method, both can be very useful for industrial applications.
Applications of Thermal Mass Flow Meter
Thermal mass flow meters are used in a broad range of applications. Here are seven common examples of using thermal flow meters:
Natural Gas to Combustion Sources
Combustion sources such as boilers and furnaces have different efficiency. The user can determine the more efficient operation by measuring the natural gas flow rate to a combustion source. The thermal mass flow meter is ideal for measuring natural gas flow rates to individual combustion sources.
Natural Gas Submetering
In facilities with different cost centers, submetering natural gas is frequently performed for cost allocations. When the cost of utilities is allocated to the various departments, there is an increased incentive to improve efficiency and reduce natural gas usage.
Compressed Air
Industrial air compressors use more electricity than most other industrial equipment and account for as much as a third of the energy consumption in a plant. A thermal mass flow meter helps determine the optimal number of compressor units needed. Additionally, air leaks waste up to 30% of the industrial compressor’s output. Thermal mass flow meters help define the extent of leakage in a system and quantify the lost energy. For more information, read “ISO 50001 Energy Management: The Use of Thermal Mass Flow Meters in ISO 50001 Energy Management Systems.”
Biogas Production
Biogas is produced in landfills as landfill gas and in anaerobic digesters as digester gas, among other places. It is high in methane and is often the focus of biogas-to-energy projects. An accurate gas flow measurement, whether monitoring, biogas destruction, or cogeneration, is needed throughout the production. Specific gas flow is also necessary for GHG emissions reporting to environmental agencies and carbon credit programs. Read “Digester Gas Flow at Wastewater Treatment Plants” or “Landfill Gas Monitoring, Recovery, and Flaring.”
Flare Gas
Flare gas measurement and monitoring are necessary to ensure the system operates correctly. This application is complicated by varying gas compositions. To learn more, read “Flare Gas Measurement Using Thermal Mass Flow Meters.”
Aeration Air
The activated sludge process is used at wastewater treatment plants to treat sewage and industrial wastewater. Microorganisms require Air flow to break down organic waste in this process. An optimum air flow throughout the system, sufficient to encourage waste consumption by the microorganisms (yet not excessive), is continuously sought.
Combustion Air
Optimizing air-to-fuel ratios through accurate and repeatable gas flow measurement achieves combustion efficiency and energy management. Direct measurement of combustion air flow and fuel flow provides the criteria for peak efficiency.
FAQ
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