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V-cone flowmeter

LGV series V-cone flowmeter uses the throttling effect of v-cone in the flow field to measure the fl…

I. Product Overview:

LGV series V-cone flowmeter uses the throttling effect of v-cone in the flow field to measure the flow rate by detecting the pressure difference between upstream and downstream. Compared with ordinary throttle parts, it changes the throttle layout from a center hole to a ring throttle. Compared with other flow meters, the flowmeter has the advantages of high long-term accuracy, good stability, small installation conditions, wear resistance, wide measuring range, small pressure loss and suitable for dirty media. And V cone itself as a rectifier of the flow field has become a new flowmeter with excellent performance.

And V cone itself as a rectifier of the flow field has become an excellent new flowmeter with d.u characteristics. The v-cone flowmeter, which is composed of v-cone sensor, differential pressure transmitter and intelligent flow integrator, can accurately measure the flow of various media in the wide Reynolds number range (8×103≤Re≤5×107). Now the V-cone has achieved international standardization, but it is a hot spot in the field of international flow measurement. It is believed that in the near future, with the further research, theoretical and experimental data perfection, it will become one of the standard throttle devices, as well as the standard orifice plate, standard nozzle and classic Venturi flow meter.

Ii. Working principle:

The LGV series V-cone flowmeter consists of a coaxial pointed cone mounted in a measuring tube and corresponding pressure inlet. The measuring tube is precision machined to generate differential pressure at both ends of the pointed cone. The differential pressure (positive pressure) is the static pressure measured at the pipe wall opening before upstream fluid contraction. And the low pressure (negative pressure) is taken from the cone toward the downstream end cone central axis hole pressure.

The * direction of the cone is towards the flow, and a sharp Angle between the cone and its tail surface provides a smooth transition zone for the fluid before entering the downstream low pressure zone.

Because the fluid is not forced to shrink near the central axis of the pipe, and is not a barrier, so that the fluid flow direction change, but the use of the novel structure of the V-cone throttling device to achieve the fluid gradually towards the pipe wall of the contraction, so that the V-cone flow meter has a series of d.U. special advantages. The low voltage side produces small eddy current with high frequency and low amplitude, so the differential pressure measured by the differential pressure transmitter is a low noise signal, which can make the differential pressure transmitter measured with high resolution, so that the V-cone can obtain a very wide range ratio and very good repeatability.

The square root of the differential pressure value generated by the flow sensor is proportional to the flow:

Qv= (c.ε)/(1-β4) 0.5. (π/4).d2.0.5

Where: Qv: volume flow of fluid

C: outflow coefficient;

ε : fluid expandability coefficient;

β : throttle ratio;

D: diameter of restrictor;

Delta Rho: Differential pressure value;

ρ1: fluid working density.

Iii. Application, conditions and Maintenance:

Medium quality: Coal gas, natural gas, including humidity below 5%), all kinds of hydrocarbons (including HC gas moisture), all kinds of rare gas (hydrogen, helium, argon, oxygen, nitrogen, etc.), wet chlorine gas, air (including water cut, including SiO2 particles and other air suspension), flue gas, saturated steam (including steam and water two phase flow), superheated steam, water, etc.

Strip: from cryocooling to supercritical state, high temperature up to 700℃, pressure up to 40Mpa.

Calculation: Each cone is calculated using special software based on fluid properties, pressure and temperature. Users can select β value according to their own application conditions (the components of the measured medium, temperature, pressure, pipe diameter, large flow, common flow, small flow, permissible pressure loss).

Maintenance: conical flowmeter maintenance free, do not need regular maintenance and verification.

Iv. Main Features:

1, accuracy can reach 0.5%.

2, the range ratio of the typical value of 15:1, at least 10:1 range ratio, far better than the hole plate, nozzle and other traditional flow meter.

3. Repeatability is better than ± 0.1%.

4, installation requirements of the straight pipe section is very short, upstream requirements 0 to 3D, downstream requirements 0 to 1D; There is no need to install a flow regulator upstream of the V-cone. Greatly saving the cost and installation space under fixed working conditions.

5, flow meter structure design is fluid sweep type structure, it is impossible to intercept any entrap gas, liquid or solid dirt in the fluid, very suitable for dirty fluid flow measurement, such as coke oven gas, wet gas, etc.

6. Specially designed inner cone can reduce the amplitude of pulsation (oscillation) in the measured pressure (differential pressure) field, thus reducing the noise in the differential pressure signal. Smaller flow can be measured, so that the range ratio widened.

7, no moving parts, high reliability, not easy to produce stuck.

8. When the fluid flows through the inner cone with a special profile, a boundary layer will be formed around it and the fluid will be diverted away from the tail edge of the cone, so as to reduce the possibility of wear and ensure the stability of its performance.

9, small pressure loss, small energy loss, dirt resistance. Suitable for low static pressure fluid flow measurement applications, such as flue gas.

10, easy to install, is the ideal flow meter for technical transformation.

11, maintenance-free or maintenance of the workload is very small, with flow adjustment and fluid mixing.

Five, technical parameters:

1, nominal passage: 50mm≤DN≤1800 mm;

2, nominal pressure: PN≤40Mpa;

3, Reynolds number range: 8×103≤Red≤107;

4, accuracy grade: 0.5, 1.0;

5, repeatability: ≤ 0.1%;

6, front straight section: 1 ~ 3D, back straight section: 3 ~ 5D;

7, small pressure loss: only 1/2 ~ 1/3 of the hole plate;

8. Small vortex at the back edge of the cone, stable negative pressure side output, small fluctuation and good stability;

9, range ratio width: flow range can reach: 1:15.

The flange type:

1, connection mode: flange (flat welding and butt welding);

2, caliber: DN15 ~ DN2000;

3, pressure method: socket welding, flange, thread;

4, pressure: 0 ~ 40MPa;

5, temperature: -40 ~ 850℃;

6, material: 304 stainless steel, 316L stainless steel, 20# carbon steel (see the selection table);

7, application: liquid, gas, steam;

8, applicable medium: widely used in municipal, electric power, chemical, petrochemical, metallurgy, food processing and other industries in the flow measurement, almost suitable for all gas, liquid medium.

Direct welding type:

1, connection mode: directly welded to the process pipeline;

2, caliber: DN15 ~ DN2000;

3, pressure method: socket welding, flange, thread;

4, pressure: 0 ~ 40MPa;

5, temperature: -40 ~ 850℃;

6, material: 304 stainless steel, 316L stainless steel, 20# carbon steel;

7, application: oil pipeline, gas pipeline, steam pipe network, high pressure process pipeline.

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