Vortex flow meters are mainly used for flow measurement of industrial pipeline media fluids, such as gas, liquid, steam and other media. The vortex flow meter is characterized by small pressure loss, large measuring range, and high accuracy. When measuring the volume flow rate under working conditions, the vortex flow meter is almost not affected by parameters such as fluid density, pressure, temperature, and viscosity. There are no moving mechanical parts, so the vortex flow meter has high reliability and low maintenance. Instrument parameters can be stable for a long time. The vortex flow meter uses a piezoelectric stress sensor, which is highly reliable and can work within the operating temperature range of -20°C to +250°C. The vortex flow meter has analog standard signals and digital pulse signal output, which is easy to use with digital systems such as computers. It is a relatively advanced and ideal flow meter. But there are also some issues that need to be noted.

1. Minimum flow problem of vortex flowmeter

The amplitude of the signal of the vortex flowmeter is proportional to the square of the flow velocity and the density of the measured medium. That is to say, when the detection sensitivity of the vortex flowmeter is certain, the working pressure of the fluid increases, the density increases, and the measured flow rate can be reduced. In turn, under a certain flow rate of the vortex flowmeter, if the working pressure of the fluid As the density increases, the signal amplitude of the vortex flowmeter also increases, and the detection sensitivity of the vortex flowmeter can be lowered. For atmospheric pressure gas, the lower flow rate of the vortex flowmeter can reach 4~5m/s. For pressurized gases, such as compressed air, the lower limit flow rate will decrease due to the increase in density. Therefore, when selecting, the actual operating flow rate must be considered.

2. Influence of vibrating vortex flowmeter

Compressed air is generated by an air compressor or a high-pressure blower. When these equipments are running, they all vibrate to varying degrees, and sometimes the vibrations are relatively strong. This vibration will be transmitted through the connecting pipes. When selecting and determining the location of a vortex flowmeter, this influencing factor should be fully considered. In various detection methods, due to different detection components, the anti-vibration performance of the vortex flowmeter is also different. For the vortex street of the detection element, the vibration resistance can reach 0.5~1G. When determining the installation location of the vortex flowmeter, try to keep it as far away from power equipment as air compressors and fans.

3. The influence of pulsating flow on vortex flowmeter

Because most of the gas output by fans and compressors contains pulsation with a certain component. For the vortex flowmeter, the pulsation frequency and amplitude of the gas output by the Roots blower are related to the rotation speed of the waist wheel and the fixed displacement volume. Usually the pulsation frequency is 100~200HZ; while the frequency of the reciprocating compressor output gas Lower, usually only a few Hz. In addition, some air-using equipment, such as air hammers and pneumatic tools, will also cause air flow pulsation, and the frequency and amplitude of this pulsation are random.