Gas mass flow controller (MFC) and gas mass flow meter (MFM). MFC is a device with the function of controlling gas mass flow, while MFM is a device without the function of controlling gas mass flow

MFC is the abbreviation of Mass Flow Controller, mass flow control. When the fluid flows in the rotating camp, it will produce a force on the pipe wall. It was discovered by Coriolis when he studied the hydraulic turbine in 1832, which is called Coriolis force for short. The mass flow meter is based on Coriolis force. There are two parallel T-shaped vibrating tubes inside the sensor, the drive coil is installed in the middle, and the vibration pickup coil is installed at both ends. When the excitation electric signal provided by the transmitter is added to the drive coil, the vibrating tube will undergo reciprocating periodic vibration. When the fluid medium of industrial process flows through the vibrating tube of the sensor, the Coriolis force effect will be generated on the vibrating tube, causing the two vibrating tubes to torsional vibration, The pickup coils installed at both ends of the original tube will produce two sets of signals with different phases. The difference between the two signals is proportional to the mass flow of the fluid flowing through the sensor. The computer calculates the mass flow through the vibrating tube. When different media flow through the sensor, the main vibration frequency of the vibrating tube is different, and the media density can be calculated according to this. The platinum anode installed on the vibration tube of the sensor can indirectly measure the temperature of the medium.

The mass flowmeter can directly measure the mass flow of the medium passing through the flowmeter, and can also measure the density of the medium and indirectly measure the temperature of the medium. Because the transmitter is an intelligent instrument with a single chip computer as its core, more than ten parameters can be derived for users to use according to the two basic quantities mentioned above. The mass flowmeter is a new generation of flow meter with flexible configuration, powerful function and high performance-price ratio.

Flow measuring instrument for measuring the mass flow in the pipeline. Under the condition that the measured fluid is in a large change of parameters such as force and temperature, if only the volume flow is measured, it will bring too much measurement error due to the change of fluid density. In the volumetric and recreational flow meters, the density of the measured fluid may change by 30%, which will cause an error of 3040% in the flow. With the improvement of automation level, many production shifts have put forward new requirements for flow measurement. The chemical reaction process is controlled by the quality of raw materials (not the volume). The heating and cooling effects of steam and air flow are also proportional to the mass flow. The strict control of product quality, accurate cost accounting, and fuel quantity control of aircraft and missiles also require accurate mass flow measurement. Therefore, the mass flow meter is an important flow measurement instrument.