How to fully understand V-cone flowmeter or differential pressure flowmeter

RD-LVD series V-cone flowmeter is a brand-new differential pressure flow metering device, which changes almost all the shortcomings of traditional throttling devices with its unique side wall tapering throttling method and can meet the application conditions of various media. Its working principle is the same as other types of differential pressure principle, and it is based on the energy conservation theorem in sealed pipelines. Because of its unique design structure, cone flowmeter has better performance.

V-cone flowmeter is composed of V-cone flow sensor and differential pressure transmitter. It is one of the most advanced differential pressure flowmeters at present, and can accurately measure the flow of various media in a wide Reynolds number range (8× 103 ~ 5× 107). V-cone flow sensor is resistant to high temperature and has no moving parts. Compared with orifice flowmeter and other common throttling elements, it has the advantages of high long-term accuracy, good stability, little influence by installation conditions, wear resistance, wide range and small pressure loss. It is suitable for measuring the flow of liquid, gas and steam in various industries, especially for measuring dirty media.

The V-cone flowmeter can measure the flow of gas phase, mixed gas phase, liquid phase, multiphase liquid, gas-liquid two-phase (water/liquid mass ratio ≤5%), powder, high viscosity, high flow rate, dirty liquid phase containing solid suspended particles, solution vibration and electromagnetic interference under various working conditions (temperature and pressure). The conditions of the fluid can range from low temperature to supercritical. The maximum working temperature is 850℃ and the maximum pressure is 42.0mpa. If special structural materials are used, the temperature and pressure can be higher. It can measure the highest Reynolds number of 5 million and the lowest Reynolds number of 8,000 or even lower. From the lowest value below 0. 1 kPa to the highest value of several tens of kPa, the full-scale pressure difference signal is generated.

Working principle of V-cone flowmeter;

V-cone flowmeter is a differential pressure flowmeter. The flowmeter designed according to the principle of pressure difference has been used for more than one hundred years. The differential pressure flowmeter is based on the principle of energy conversion in a sealed pipeline, that is to say, for a stable fluid, the pipeline pressure is inversely proportional to the square root of the velocity of the medium in the pipeline: the pressure will decrease with the increase of the velocity; when the medium approaches the cone, its pressure is p 1; when the medium passes through the throttling area of the cone, the velocity will increase and the pressure will decrease to p2. As shown in figure 1, p 1 and p2 are led to the differential pressure transmitter below through the pressure tap of the conical flowmeter. When the flow rate changes, the pressure difference between the two pressure taps of the cone flowmeter will increase or decrease. Under the condition of the same flow rate, if the throttling area is large, the pressure difference will be large, and the β value is equal to the throttling area of the cone divided by the cross-sectional area of the inner diameter of the pipeline (which can be converted into the diameter ratio of the two).

Product features of V-cone flowmeter;

1. Compared with other throttling differential pressure flowmeters, it has wear resistance and small pressure loss.

2. The requirements for installing straight pipe sections are low, with the upstream straight pipe section being 0 ~ 3d and the downstream straight pipe section being 0 ~1d..

3. Good anti-vibration and anti-interference.

4. The instrument is resistant to high temperature, and its working temperature can reach 700℃.

5. The pipe diameter has good applicability. By choosing different β values, different flow measurement ranges can be selected without changing the pipe diameter, thus avoiding the trouble of pipe shrinkage.

6.V-cone flowmeter is non-viscous, anti-clogging, and has self-cleaning function, which is suitable for the flow measurement of dirty fluids (such as coke oven gas and residual oil).

Main technical indexes of V-cone flowmeter:

1, nominal diameter: dn50 ~ dn3000 (for welding above dn700);

2. Nominal pressure: PN 1.0, PN 1.6, pn 4.0 (MPa);

3. Accuracy grade: 0.5,1.0;

4. Repeatability: 0. 15%, 0.30%;

5. Range ratio10:1;

6. Working temperature range:-40℃ ~ 700℃;

7. Ambient temperature range:-20℃ ~ 65℃;

8. Applicable fluid media: gas, liquid, saturated steam and superheated steam.

Selection table of RD-LVD series v-cone flowmeter:

Type number statement

Rd-lvd v-cone flowmeter

Instrument diameter (mm) 50 DN50

100 DN 100

… …

3000 DN3000

Component material material conical steel pipe flange

A piece of SS304 20# 20#

B SS304 15CrMo 15CrMo

C SS304 SS304 20#

D stainless steel 304 stainless steel 304 stainless steel 304 stainless steel 304 stainless steel 304

E SS3 16L SS304 SS304

g ss 3 16L ss 3 16L ss 3 16L

# Other materials

Measuring medium 1 liquid

2 gas

3 steam

4 high temperature medium

Compensation form without pressure and temperature compensation.

Q-band pressure and temperature compensation output

Connection form L threaded connection (suitable for small diameter)

W flange connection

Pressure class 2 1.0 MPa

4 2.5 MPa

5 4.0 MPa

6 6.3 MPa

Optional accessory J of V-cone flowmeter with stop valve

L with condenser tube

S-band three-valve group

CB differential pressure transmitter

XJ flow integrator

BC temperature and pressure compensation with temperature and pressure sensor