What is a Thermal Mass Flow Meter?

Thermal Mass Flow Meteris an accurate, easy-to-install, low pressure drop flowmeter. It is suitable for flow measurement and control of dry gas applications. can alsoby gas typeReference linkapplication toObtain a thermal mass flow meter. A mass flow meter observes the cooling effect on the transducer it heats as a function of airflow. The result achieves a high level of accuracy at low cost compared to other gas flow measurement devices.

benefit:

• ·High accuracy
• Wide flow range, including low flow
• · Simple, durable construction
• ·Easy to install and maintain
• Flexible connection of flow meters for flow control
• · Various process connections
• ·Tuning ratio 100:1
• Low pressure drop across the flow meter
• ·Provide convenient signal output

Thermal Mass Flow Meter Principle

Thermal Mass Flow MeterUse the thermal properties of the fluid to measure the motion of the fluid in a pipe or tube. In a thermal energy flow meter, the measured heat is applied to the heater of the sensor. A certain amount of energy is lost during the flow, and as the flow increases, more energy is lost. The energy lost by the sensor depends on the thermal properties of the fluid and the sensor design. The thermocompressive properties of fluids can vary with temperature and pressure, although these changes are usually insignificant in most applications. Since thermal flow measurement does not depend on the temperature or pressure of the fluid, thermal energy flow meters can be used to estimate the mass flow of the fluid.

In other words, in most applications, the properties of a fluid may depend on its composition. For these applications, different compositions of the fluid may interfere with the heat flow size during actual operation. Therefore, forThermal Mass Flow MeterIt is important for the provider to understand the composition of the fluid so that the appropriate normalization factors can be processed to accurately determine the flow rate. Due to this limitation,Thermal Mass Flow MeterUsually used to measure the flow of pure gas. Manufacturers can provide appropriate standardized information for other gas combinations, butThermal Mass Flow MeterThe accuracy of the depends on whether the actual gas mixture is the same as the gas mixture used for normalization purposes.

Mass Flow Controller Applications

• Plasma Cleaner
• Gas diverter valve box/panel
• Gas cylinder cabinet output flow control
• Gas generator output control
• flame welding control
• Gas source piping measurement

What types of mass flow controllers exist in the TMFM/TMFC series?

Thermal mass flow controllers use the thermal mass sensing technique of gases to control their mass flow. In the TMFC portfolio we have several thermal mass flow controllers, each with its own sensor technology:

Mass flow controllers using bypass sensors. These devices, such as TMFCs and TMFMs, are ideal for clean and dry gas applications where greater precision and repeatability are required.
Mass flow controller using the on-line principle. Series such as the TMFC and TMFM series are perfect if your application has high purity gases above 99.9%, or when high repeatability and robustness are more important than accuracy.
Gas mass flow controller using piping control technology. These series stand out because they can measure gas flow and control.
Whenever your mass flow needs to be displayed and over a wide flow range, a gas series using MEMS chip sensor technology such as the TMFM6000 is perfect.
Gas mass flow controllers using in-line (CMOS) technology.

Mass Flow Controller ( MFC ) Principle / Flow Controller Principle

A mass flow controller (MFC) is a device used to measure and control the flow of liquids and gases. [1] Mass flow controllers are designed and calibrated to control a specific type of liquid or gas over a specific flow range. The MFC can have a set point between 0% and 100% of its full scale range, but typically operates within the full scale range of 10% to 90% for best accuracy. The device will then control the flow rate to the given set point. MFCs can be analog or digital. Digital flow controllers are usually capable of controlling more than one fluid, while analog controllers are limited to the fluids they are calibrated for.

All mass flow controllers have an inlet port, an outlet port, a mass flow sensor, and a proportional control valve. The MFC is equipped with a closed loop control system where the operator (or external circuit/computer) provides an input signal which is compared with the value of the mass flow sensor and adjusts the proportional valve accordingly to achieve the desired flow. Flow is specified as a percentage of its calibrated full scale flow and is provided to the MFC as a voltage signal.

Mass flow controllers require the supply gas or liquid to be within a specific pressure range. Low pressure will deplete the MFC of fluid and prevent it from reaching its set point. High pressures may cause erratic flow rates. There are many different technologies that help measure the flow of fluids and ultimately help control flow. These technologies define the types of mass flow controllers and they include differential pressure (ΔP), differential temperature (ΔT), Coriolis force, ultrasonic, electromagnetic, turbine, etc.

Mass Flow Meter Installation

Now there are more and more applications of mass flowmeters, and some occasions where mass flowmeters are installed for the first time are not clear about the installation method of mass flowmeters, reverse installation, wrong installation, etc., which affect the normal use of the equipment. This article discusses this problem Describe in detail how to install a mass flow meter.

Excessive mechanical stress during sensor installation will affect the zero point of the mass flowmeter. If these stresses are constantly changing, the zero point drift of the meter will cause inaccurate measurement and cannot work normally. Therefore, the correct installation of the mass flowmeter is an important part of ensuring the normal operation of the equipment.

1. Choose the installation method

The installation method of the sensor is mainly determined according to the phase difference of the fluid and its process conditions. There are three installation methods.

1. If the measured fluid is a liquid, the sensor is generally installed with the shell facing down to avoid air accumulation in the vibrating tube of the sensor, so as to achieve the purpose of accurately measuring the mass flow rate.

2. If the measured fluid is gas, the sensor is generally installed with the shell facing upwards to avoid accumulation of condensate in the sensor vibration tube.

3. If the measured fluid is a mixed slurry of liquid and solid, install the sensor on a vertical official road, which can prevent particles from accumulating in the sensor's Coriolis force measuring tube. In addition, if the process pipeline needs to be cleaned with gas and steam, this installation method can also facilitate cleaning, but this installation method is more difficult to fix than the previous two, and the pressure loss is larger.

 

 

 

 

 

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