Vortex flowmeter is a new type of flow measuring instrument made according to the "Karmen vortex" principle.
When a stable fluid flows through a straight pipe with a certain length, a nonlinear cylinder immersed in the fluid is struck, and a vortex (ie, a Karman vortex) is generated downstream of the fluid.
When the Reynolds number (Re) of the fluid is within a certain range, the regularity of the occurrence of the vortex is stable and reliable, and the frequency of the vortex F is defined by the formula:

F = (St * V) / d is determined where, V is the flow velocity; d is the width of the flow surface of the cylinder; St is the Strohal number.

The Strohal number is a dimensionless parameter. The following figure shows the relationship between the Strohal number and the Reynolds number. Within a certain range of Reynolds number, the Strohal number remains basically the same, so that Renault can be considered The number of Karman vortices released in this range is proportional to the fluid velocity. Therefore, the flow velocity V can be obtained from the detected frequency F, and the volume flow can be obtained from V.

Vortex flowmeter profile

Vortex flowmeter characteristics and uses

a : Features:
1 Anti-vibration performance is very good, no zero drift, high reliability. Through long-term analysis of waveforms and frequency spectrum analysis of vortex flowmeters, coupled with optimum probe shape, wall thickness, height, diameter of probe rods, and matched piezoelectric crystals, advanced CNC lathes are used for processing. To ensure that the processing of the coaxiality and smoothness and other technical parameters, with a special process, so as to maximize the vortex flowmeter to overcome the inherent self-oscillation frequency of the impact of the signal on the common problem.
2 The sensor of the intelligent vortex flowmeter is very versatile, so that the sensor has a good interchangeability. The use of advanced numerical control equipment to process the sensor body and vortex generating body, to ensure the processing accuracy, so that parts (especially vortex) The versatility of the body is so strong that it does not affect the repeatability and accuracy of the sensor due to the replacement of parts; it can produce a strong and stable vortex signal.
3 The structure is simple and solid, no moving parts, high reliability, easy to use and maintain.
4 The detection element is not in contact with the medium, the performance is stable, and the service life is long. The sensor uses the detection probe and the vortex generating body to be installed separately, and the high-temperature piezoelectric crystal is sealed in the detection probe and is not in contact with the measured medium, so the vortex flowmeter It has the characteristics of simple structure, good versatility and high stability.
5Output pulse signal or analog signal proportional to flow, no zero drift, high precision, convenient and computer networking
6 wide measurement range, up to 1:10 ratio
7 When vortex flowmeters measure volume flow without compensation, the signal output by vortex street is actually linear with the flow rate, which is proportional to the volume flow. The purpose of pressure and temperature compensation is to obtain the density of the fluid, multiplied by the volumetric flow to obtain the mass flow, and if the volume flow of the measured gas does not need to be compensated.
8 The pressure loss is small. A flow meter measuring the flow of combustible gas by vortex diameter of DN50, if the maximum flow rate in the conduit Qmax = 200m3 / h, the pressure loss sensor is: △ P = 1.08 × 10-6 ρv2 (kPa) = 0.605 KPa
9 Within a certain Reynolds number range, the flow characteristics are not affected by the fluid pressure, temperature, viscosity, density, and composition, and are only related to the shape and size of the vortex generator.
10 Wide application range, steam, gas, liquid flow can be measured.
b : Use:
The flowmeter can be widely used in large, medium and small-sized pipes for water supply and drainage, industrial circulation, sewage treatment, oil and chemical reagents, and measurement of compressed air, saturated and superheated steam, natural gas, and various medium flows.

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