Products
Descipion
Product features and main technical parameters
●Simple structure, no moving parts in the product
●Detecting element does not contact the detected medium
●Stable performance, long service life
●The liquid, gas and steam can be measured by the same sensor
● Within the required Reynolds number, the meter coefficient is not impacted from the changes in the fluid temperature, pressure, viscosity and composition.
●The instrument applies to the Reynolds number range:
2X104-7X106(DN25-DNl00)4X104-7X106(DNl50--DN300
●The ordinary type product can realize the instantaneous and cumulative display
●Temperature and pressure compensation instrument can automatically calculate the parameters such as displayed standard flow and working condition flow, temperature and pressure, etc.
●Steam temperature and pressure compensation instrument can automatically calculate the parameters such as displayed mass flow, temperature, pressure, and density, etc.
●Working Pressure:1.6～4.0MPa
●Medium temperature: -40℃~+200 (integration type) -40℃~+300 (separate type)
●Ambient temperature:-25℃～+60℃
●Relative humidity:5%～95%
●Atmospheric pressure:86～106KPa
●Measured fluid type: liquid, gas, steam
●Accuracy: 1 class, 1.5 class
●Output signal:
Analog Output: (fully isolated two-wire system 4-20mA) Remote transmission distance of 1000m
Pulse output: (fully isolated three-wire system VH 3V) Remote transmission distance of 500m
485 output: (fully isolated 485 output, modbus protocol, it can be connected directly to PLC and computer configuration software, without the need to write the drive by yourself, it can carry up 256 loads) Remote transmission distance of 1200m
Wireless Output: (Fully isolated wireless output, modbus protocol, it can be connected directly to PLC and computer configuration software, without the need to write the drive by yourself, it can carry up 256 loads) Remote transmission distance of 4500m
2. Working Principle
When a non-streamlined cylinder (vortex generating body) is inserted in the fluid in the vertical flow direction, two vortex columns (internal rotation) would be alternately produced at its downstream side, which is called "Karman vortex".
Within a certain range of Reynolds number, there is the following relationship among the vortex release frequency f, flow rate V of the fluid and front width d of the vortex generating body:
2
f=st*v/d (1)
Wherein: St: strouhal number (dimensionless constant)
It can be seen from the above formula that the flow rate V of the flow can be measured as long as the frequency f of vortex is detected, so as to measure the flow Q of the fluid in the measurement pipeline
V=f*d/St (2)
Q=v*S=f*d/St*S (3)
Wherein: cross-sectional area of the S pipeline
d / St * S is a constant, if 1/K is equal to d/St*S, then
Q=f/k (4)
Wherein: Meter factor of K-flow meter (pulse number/liter) is usually obtained by actual flow test.
Because the vortex is alternately generated on both sides of the vortex generating body, the vortex force will act on the test body, so that the alternating stress is generated. The stress will act on the piezoelectric element to produce the same alternating charge signal as vortex frequency. After it is processed through the converter, the pulse signal that is the same as vortex frequency or 4-20mADC signal that is proportional to the flow is output.
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