In China, the material balance in the production process, the economic accounting in production management, and the measurement in the custody transfer process are mostly based on the quality unit. Differential pressure, volumetric, speed-type flowmeters and methods of measuring capacity, such as the manual inspection of oil tanks, measure the volume of the fluid. With the change of working conditions, some characteristic parameters of the fluid such as temperature, pressure, density, viscosity, etc. will change. In the occasion where the working condition changes greatly, the above measurement methods often fail to accurately measure the mass flow of the fluid. Therefore, the development of thermal air mass flow meter has very important significance for the handover measurement and process control.

Thermal gas mass flow meters are widely used because of their high measurement accuracy, wide range ratio, wide range of applicable media, and good reliability. Thermal mass flow meters are mainly based on liquid media and can also be used Measurement of medium and high pressure gas media. At present, the measurement of general liquid media such as gasoline, kerosene, and diesel oil is mostly performed by manual or volumetric flowmeters for oil tanks, that is, the actual liquid level of the tank must first be measured with a dipstick (or meter). Calculating its volume based on the tank table and multiplying it by the density is the mass flow of the oil. This not only takes into account the accuracy of the instrument itself, but also takes into account the influence of parameters such as temperature and deviations during operation. The use of mass flow meters avoids deviations from the latter. The following discussion on the installation of hot gas mass flow meters.

Thermal mass flow meter installation:

1) The thermal gas mass flowmeter works based on the principle of vibration, and in the course of its work, it also uses electromagnetic technology for vibration excitation, torsion angle detection and detection signal processing, so the thermal air mass flowmeter The installation location cannot have a large vibration source, nor can it be installed near a device that generates a strong magnetic field such as a transformer or a motor to prevent outside interference from affecting its normal operation.

2) The installation of the hot gas mass flow meter requires no straight pipe section, but the stress should be avoided when connecting the sensor and the pipe. If the thermal gas mass flowmeter installation process, the sensor and the pipe centerline concentricity deviation, will cause the vibration tube to produce stress, the stress will form a pressure, tension, or shear force affect the alignment of the pipe, causing the detection probe The asymmetry causes zero-point changes and affects the measurement accuracy. If the concentricity deviation between the pipe and the sensor is too large, the zero point may not be adjusted. Therefore, reinforcement measures should be taken to stabilize the pipeline near the instrument. When installing the flow sensor, it should be as flexible as possible. The flange connection screws should be evenly and symmetrically fastened. To reduce the effect of residual stresses, the flow sensor must be calibrated to zero after it has been installed. In order to facilitate the installation and zeroing of thermal air mass flowmeters, shutoff valves are also installed on the front and rear ends of thermal mass flow meters.

3) The sensor and transmitter connection cable should use the manufacturer's special cable; the transmitter receives a low-level signal, so the cable should not be too long. When installing the transmitter, ensure that the partitions that separate the intrinsically safe sensor cable from the power supply and output cables are in place; make sure that the sensor junction box and transmitter housing are well sealed to prevent short circuits that may cause measurement errors or flow meter failures.