Mass flow controller (MFC) is used for precise measurement and control of mass flow rate of gas. It is usually composed of flow sensor, flow control valve, amplifying control circuit and shunt control channel. Its work power supply and flow display and setting operations by its supporting flow display power supply.
Use and features
MFC plays an important role in scientific research and production in many fields such as semiconductor microelectronics industry, special material development, chemical industry, petroleum industry, medicine, environmental protection and vacuum.
The typical applications include: Electronic process equipment such as diffusion, oxidation, epitaxy, CVD, plasma etching, sputtering, ion implantation; and vacuum coating equipment, Gas chromatographs and other analytical instruments.
Mass flow controller and mass flowmeter with high accuracy, good repeatability, fast response speed, soft start, stable and reliable working pressure range (which can work under high pressure or vacuum conditions), the operation is easy to use. MFC can be installed in any position, and is connected with the computer to realize automatic control.
The flowmeter is generally divided into the following types:
1. Volumetric flowmeter
It uses the mechanical measuring element to continuously divide the fluid into a single known volume part. The volume flow of the fluid is measured according to the number of times of the volume of fluid filled and discharged one after another in successive from the measuring chamber.
2. Float flowmeter (rotor flowmeter)
The float flowmeter is a kind of variable area flowmeter, in a vertical cone from up to down, the circular cross section of the float gravity is supported by the liquid power, so that the float can be free in the cone Rise and fall.
3. Differential pressure flowmeter
It is based on the differential pressure produced by the flow detector installed in the pipe, the condition of the known fluid and the meter to calculate the flow between the pipe and the pipe.
4. Vortex street flowmeter (VSF)
The non-streamline vortex generator is placed in the fluid and the fluid is alternately separated on both sides of the generating body to release two series of regularly interlaced vortex instruments.
5. Turbine flowmeter
It is the main type of velocity flowmeter. It uses the multi blade rotor (turbine) to sense the average velocity of fluid, and deduces the instrument of flow volume or total quantity.
6. Ultrasonic flowmeter
It is measurement of flow by measuring the effect of fluid flow on the ultrasonic beam (or ultrasonic pulse).
7. Electromagnetic flowmeter
The electromagnetic flowmeter is a kind of instrument for measuring the conductivity of the liquid according to the law of Faraday's electromagnetic induction.
8. Thermal mass flowmeter
The thermal flowmeter sensor contains two sensing elements, a speed sensor and a temperature sensor. They can automatically compensate and calibrate the temperature change of the gas. The electric heating part of the instrument heated the speed sensor to a certain value higher than the temperature of the working condition, so that a constant temperature difference between the speed sensor and the sensor at the working temperature condition was formed. When the temperature difference is kept constant, the energy consumed by electric heating is proportional to the mass flow of the flow of gas, and is suitable for the measurement of a single gas and fixed proportion of multi-component gas.