Vortex flowmeter conditions of use

The accuracy of o is approximately ±0.5[%]R to ±2[%]R for liquid, and ±[%]R to ±2[%]R for gas, and the repeatability is generally 0.2[%] to 0.5[ %]. Because the flowmeter VSF has a low meter factor and low frequency resolution, the larger and lower the caliber, the caliber of the meter should not be too large.

The range width is a characteristic of the VSF, but what is important is how much the lower limit flow is. The lower limit of the average liquid velocity is generally 0.5 m/s, and the gas is 4 to 5 m/s. The normal flow rate of VSF is better than 1/2 to 2/3 of the normal measurement range. The instrument factor of the VSF is not affected by the physical properties of the measurement medium. This is a great advantage. It can be applied to other media with a typical media calibration, which is convenient for solving calibration equipment problems. However, it should be noted that the range of the flow rate of liquid and gas varies greatly, so the frequency range also varies greatly. In an amplifier circuit that processes vortex signals, the passbands of the filters are different and the circuit parameters are also different. Therefore, the same circuit parameters cannot be used for different measurement media. Changes in the medium, the circuit parameters should also change.

The density of gas and liquid varies greatly, and the intensity of the signal generated by vortex separation is proportional to the density. Therefore, the difference in signal strength is also great. The gain of the liquid and gas amplifier circuits and the trigger sensitivity are all different. Piezoelectric charge has a large difference, and the parameters of the charge amplifier are also different. Even if the same gas is used with different pressures and temperatures of the medium and the density is different, the used flow range is different, the signal strength is also different, and the circuit parameters also have to be changed. Therefore, it is not feasible to change the media or change the gauge diameter of a VSF without hardware or software modification.

Vortex flowmeters are not suitable for measuring low Reynolds number fluids. When the Reynolds number is low, the Strouhal number changes with the Reynolds number, the linearity of the instrument becomes worse, and the high fluid viscosity will significantly affect or even hinder the generation of vortices. One of the limitations of the type selection is that it cannot be used at the boundary Reynolds number. under. The vortex flowmeter is suitable for a wide range of fluids, but attention should be paid to the fluid's dirty nature. Flushing of the vortex generator with a fluid containing solid particles generates noise and wears the vortex generator. If the short fiber contained is wound on the vortex generator, the meter factor will be changed. VSF has little experience in the use of mixed-phase fluids. It can generally be used for micro-bubbles containing dispersed and uniform, but the volumetric gas-containing rate should be less than 7[%]~10[%], if the gas-liquid two-phase flow exceeds 2[ %] The meter factor should be corrected. It can be used for gas-solid, liquid-solid two-phase flow with dispersed and uniform solid particles in an amount of not more than 2 [%]. Can be used for insoluble liquid and liquid two-component flow and so on.

Pulsating and rotating flows can have a serious effect on VSF. If the pulsating frequency and the vortex street frequency band are in phase with each other, resonance may damage the normal operation and equipment, and the vortex street signal may be locked. At this time, the signal is fixed at a certain frequency. Locking is related to the pulsation amplitude, the shape of the vortex body, and the clogging ratio. The pulsation threshold for normal operation of the vortex flowmeter VSF has yet to be determined experimentally.

· The type and scope of vortex flowmeters
o 1、 LUGB/E series full-tube piezoelectric/capacitive vortex flow meter

2. LUGB/E Series Piezoelectric/Capacitive Vortex Flow Meter

3, LUGB/E series battery-powered integrated vortex flow meter

4, submersible / split vortex flow meter

5, HY-2008 intelligent flow totalizer

· Vortex flowmeter installation requirements
o The flow direction of the upflow arrow in the vortex flowmeter is the same as the flow direction of the fluid, and its installation angle is not limited.

2 Upstream straight pipe length 15-40DN, downstream straight pipe length 5DN

3 When pressure and temperature compensation are required, pressure transmitter and temperature transmitter should be equipped. The location of the pressure hole is 3-5DN ​​downstream of the sensor, and the pressure hole diameter is 6-12mm. The temperature measurement point is set at Downstream 6-8 DN.

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