Mass Flow Controllers（MFC) provide precise measurement and control of the mass flow of gases.
I. What is the difference between a MFC and a MFM?
Mass flow meter(MFM) is a kind of instrument that accurately measures gas flow, and its measurement value is not inaccurate due to fluctuations in temperature or pressure, and does not require temperature and pressure compensation.The mass flow controller(MFC) not only has the function of a mass flow meter, but more importantly, it can automatically control the gas flow, that is, the user can set the flow according to their needs, and the MFC automatically keeps the flow constant at the set value, even if the system pressure Fluctuations or changes in ambient temperature will not cause it to deviate from the set value. The mass flow controller is a steady flow device, which is a gas steady flow device that can be manually set or automatically controlled by connection with a computer. Mass flow meters only measure but do not control. The mass flow controller has a control valve, which can both measure and control the gas flow.
II. What is the structure and operation principle?
1、 Structure
2、Operation Principle
When the flow enters the intake pipe, most of the flow passes through the diverter channel, a small part of which enters the capillary tube inside the sensor. Due to the special structure of
the diverter channel, the two parts of the gas flow can be directly proportional. The sensor is preheated and heated, and the temperature inside is higher than the temperature of the inlet air. At this time, the mass flow of the small part of the gas is measured by the principle of heat transfer by the capillary tube and the principle of temperature difference calorimetry. The flow of gas measured in this way can ignore the effects of temperature and pressure. The flow measuring signal detected by the sensor is input to the circuit board and amplified and output, and the function of the MFM is completed. Adding PID closed loop automatic control function to the circuit board, Compare the flow measurement signal measured by the sensor with the set signal given by the user. Based on this, the control valve is controlled so that the flow detection signal is equal to the set signal, thus realizing the function of the MFC.
III. Applications and features.
MFC，which is widely applied in the fields as: semiconductor and IC fabrication, special materials science, chemical industry, petrolic industry, pharmaceutical industry, environmental protecting and vacuum system researching, etc.. The typical applications include: microelectronic process equipment such as diffusion, oxidation, epitaxy, CVD, plasma etching, sputtering, ion implantation; vacuum deposition equipment, optical fiber melting, micro-reaction equipment, mixing & matching gas system, capillary flow control system, gas chromatograph and other analytical instruments.
MFC bring the high accuracy, excellent repeatability, quick response, soft-start, better reliability,wide variety ranges of operation pressure (good operation in high pressure and vacuum situations), simpleconvenient operation, flexible installation, possible connecting with PC to carry out automatic control to the users’ system.
IV. How to determine and deal with failures?
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Post time: Jul-29-2022