What are the characteristics and limitations of " vortex flowmeters "? Vortex flowmeters are a new type of internationally advanced ') flowmeters that have been successfully developed based on the Carmen vortex street principle. The advantages have been developed rapidly since the 1970s. According to relevant data, the proportion of vortex flowmeters in developed countries such as Japan, Europe and the United States has increased sharply. It has been widely used in various fields and will account for future flow meters. The leading position is the most ideal substitute for orifice flowmeters, and it is also the first domestic flowmeter .
1. Characteristics of " vortex flowmeter ":
Simple and solid structure, no moving parts, high reliability and very reliable long-term operation;
Simple installation and convenient maintenance;
Detection sensor does not directly contact the medium, stable performance and long life;
The output is a pulse signal proportional to the flow rate, no zero drift, high accuracy, and convenient networking with a computer;
Wide measuring range and range ratio up to 1:10;
Small pressure loss, low operating cost, and more energy-saving significance;
Within a certain Reynolds number range, the output signal frequency is not affected by the fluid physical properties and composition changes. The meter coefficient is only related to the shape and size of the vortex generator. The volumetric flow of the measurement fluid does not need to be compensated, and there is no need to recalibrate the meter after changing accessories. coefficient.
Wide range of applications, the flow of steam, gas and liquid can be measured;
The verification cycle is two years.
Limitations of Vortex Flowmeters :
" Vortex flowmeter " is a speed type flowmeter . The stability of vortex separation is affected by the flow velocity distribution, so it has certain requirements for straight pipe sections. Generally it is the first "10D, the last 5D"; when measuring liquid, The upper limit flow rate is limited by pressure loss and "cavitation", which is generally 10 m / s. When measuring gas, the upper limit flow rate is limited by the compressibility change of the medium, and the lower limit flow rate is limited by the Reynolds number and sensor sensitivity. Generally, the flow rate range of gas is 10-70 meters / second, and the flow rate range of steam is 8-50 meters / second; The stress type vortex flowmeter is more sensitive to vibration, so when installing the vortex flowmeter in the pipeline with more vibration, the pipeline must have certain shock absorption measures; the stress type vortex flowmeter uses a piezoelectric crystal as a detection sensor, so its Limited by temperature, the general long-term working temperature is -40 ℃? + 350 ℃ and -10 ℃? + 250 ℃.
Article Keywords: Vortex Flowmeter