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Rotary flowmeter | Types and principles of flowmeters

『Rotary flowmeter』Related information(clamp on meter|electromagnetic meter|venturi meterrotameter|orifice meter|ultrasonic flow meter|mass flow meter|coriolis mass flow meter|coriolis flow meter|magnetic flow meter|magmeter flow meter|magflow flow meter|mag meter flow meter|electromagnetic flow meter|vortex flow meter|turbine flow meter|thermal mass flow meter|thermal flow meter|rotameter flow meter)

Why is the rotor flowmeter called a constant pressure drop flowmeter? This is the principle difference between rotor and differential pressure flowmeters. 1. The internal structure of the rotor flowmeter sensor is uniform, and the structure of the float is also designed with low pressure loss (relatively stable pressure). 2. The internal structure of the differential pressure flowmeter sensor is also uniform, but there is a cone. (The differential pressure type is based on the energy conversion principle in the sealed pipeline, which means that for stable fluids, the pipeline pressure is inversely proportional to the square of the medium flow velocity in the pipeline: as the speed of collapse increases, the pressure will decrease.) The working principle of the float shielded flowmeter (also known as the rotor flowmeter) is different from that of the differential pressure flowmeter. Differential pressure flowmeter reflects the magnitude of flow sensation through changes in differential pressure under the condition of constant throttling area (such as orifice plate flow area). However, the float flowmeter measures the flow rate by keeping the pressure drop constant and using the change in throttling area, that is, the float flowmeter adopts the flow measurement method of constant pressure drop and variable throttling area. If you have any questions about the intelligent system of Shenzhen AVIC Computer, please consult

2. Flow calculation formula for metal rotor flowmeter

The core flow calculation formula and correction method for metal rotor flowmeter are as follows:

1. Basic flow formula The basic formula for metal rotor flowmeter is based on the balance of floating force, and the volume flow rate

Rotary flowmeter
when ignoring viscous force is: \ [Q=C {\ mathrm {R} A_ {\ mathrm {R}} \ sqrt {\ frac {2V_ {\ mathrm {f}} (\ rho {\ mathrm {f} - \ rho) g} {\ rho A_ {\ mathrm {f}}}} Meaning of each variable: • (Q): Volume flow rate (unit: m ^ {3}/s); • \ (C {\ mathrm {R}} \): Flow coefficient (determined experimentally by float shape and Reynolds number, etc.); • \ (A_ {\ mathrm {R}} \): The annular gap area between the float and the cone tube (unit: \ (m ^ {2} \)); • \ (V_ {\ mathrm {f}} \): Float volume (unit: \ (m ^ {3} \)); • \ (\ rho_ {\ mathrm {f}} \): Float material density (unit: \ (kg/m ^ {3} \)); • \ (\ rho \): Fluid density (unit: \ (kg/m ^ {3} \)); • (g): Gravity acceleration (usually taken as 9.81m/s ^ {2} \); • \ (A_ {\ mathrm {f}} \): The maximum deficit cross-sectional area of the float (unit: \ (m ^ {2} \)).

2. The flow correction formula for practical applications needs to be corrected for differences between actual operating conditions and calibration states: 1 Gas flow correction formula: \ [\ frac {Q_ {1}} {Q_ {0}}=\ sqrt {\ frac {p_ {0}T_ {1}\rho_{0}}{p_ {1}T_ {0} \ rho_ {1}} \] • \ (p0 {0}, p0 {1} \): Absolute pressure of calibration and actual operating conditions; • (T_ {0}, T_ {1} \): thermodynamic temperature (in K) for calibration and actual operating conditions; • \ (\ rho_ {0}, \ rho_ {1} \): Gas density for calibration and actual operating conditions. two Liquid flow correction formula: \ [\ frac {Q_ {1}} {Q_ {0}}=\ sqrt {\ frac {\ rho_ {0} (\ rho_ {\ mathrm {f} - \ rho_ {1})} {\ rho_ {1} (\ rho_ {\ mathrm {f} - \ rho_ {0})} \] • \ (\ rho_ {0}, \ rho_ {1} \): Liquid density under calibration and actual operating conditions; • \ (\ rho_ {\ mathrm {f}} \): Float material density (fixed value).

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