Verabar Flowmeter

I. Overview

1, Verabar flowmeter usage

Verabar flowmeter is suitable for high-precision flow measurement of gas, liquid and steam. Verabar flowmeter is a differential pressure, rate average flow sensor, which measures the flow rate through the differential pressure generated by the sensor in the fluid. Verabar flowmeter reflects the true flow rate of the fluid, with an accuracy of ± 1.5 and a repeatability of ± 0.1. The outstanding advantage of Verabar is: it outputs a very stable, pulsation-free differential pressure signal

2. Design features of the probe

The sub-projectile cross-sectional shape of the probe can produce accurate pressure distribution, a fixed fluid separation point; the low pressure tapping holes located on the two sides of the probe side and before the fluid separation point can generate a stable differential pressure signal and effectively prevent blocking. The internal integrated structure can avoid signal leakage, improve the strength of the probe structure, and maintain long-term high precision.

3. The anti-blocking design of Verabar flow probes has got rid of the shortcomings of plug-in flow probes such as Annubar that are easy to block, so that the anti-blocking level of the average velocity tube flow probe has been improved.

The high-pressure tapping hole of the probe will not be blocked at the front of the probe to form a high-pressure zone. The pressure is slightly higher than the static pressure of the pipeline, preventing particles from entering. Please note: The velocity of the fluid at the high pressure tapping hole of the probe is zero, and no objects will enter the tapping hole. When the machine is turned on, the fluid enters the elbow under the action of the static pressure of the pipe, and a state of pressure balance is quickly formed. When the pressure balance is formed, the fluid encounters high pressure at the inlet of the elbow, detours, and no longer enters the elbow.

The low pressure hole of Verabar flowmeter realizes essential anti-blocking. Under normal circumstances, dust, sand and particles are concentrated on the back of the probe under the action of vortex force. This is why the autumn leaves are always concentrated behind the leeward house. For other probes, the low-pressure tapping hole is taken in the vacuum area at the end of the probe. Under the action of the vortex force, the low-pressure tapping hole of the probe is quickly blocked by the impurities brought by the eddy current. Verabar flowmeter makes the low pressure tapping holes located on the back two sides of the probe side, the fluid separation point and the front of the wake area. This design essentially prevents clogging and can generate a stable low-voltage signal.

4. Advantages of the probe

● It can measure a variety of media and has a wide range of applications

● High accuracy, large range ratio

● The probe pressure hole is inherently anti-blocking

● The measurement signal is stable with little fluctuation

● Low pipeline pressure loss

● High-strength bullet-shaped single-piece dual-chamber structure

● Low installation cost, basically maintenance-free

● It can be installed and repaired online

5. The characteristics of Verabar's average velocity tube flow sensor

● Stable signal

Verabar's low pressure tapping hole is located on the back two sides of the probe side, between the separation point of the fluid and the probe, away from the eddy current fluctuation area.

● Long-term high precision

Verabar can guarantee the long-term stability of accuracy, this is because:

⑴. It is not affected by wear, dirt and oil.

⑵. There are no movable parts in the structure.

⑶. Designed to eliminate the occurrence of clogging. At the front of the probe, the high static pressure area surrounds the probe, so that the high pressure tapping hole will not be blocked. The most important thing is that the low-pressure holes are taken on the back two sides of the probe side, and the fluid is slanted across the surface, protecting the low-pressure holes from being swept, and other probes are easy to block because their low-pressure tapping holes are where impurities gather. Low-pressure fluctuation area.

● Lower installation costs

⑴. Only a few inches of line welding is required, and the installation is very simple and fast.

⑵. With special tools, online installation under pressure can be realized.

⑶. The valve and the interface of various instruments only need simple assembly, which requires lower assembly costs.

● Lower operating costs

⑴. It is a non-contracting throttling design. As a plug-in flow probe, Verabar's operating cost is relatively low.

⑵. Verabar flowmeter only produces low pressure loss, typically less than 0.7KPa

⑶. The pressure loss generated by an orifice element exceeds 14KPa

⑷. Compared with the orifice plate, Verabar’s energy loss is reduced by 95%.

● The continuous working Verabar eliminates the possibility of blockage, but Verabar should still pay attention to anti-blocking under the following conditions:

⑴. When the impulse tube leaks, the high-pressure balance area of ​​the probe is destroyed, and particles with smaller diameters among the impurities may enter the extraction tube.

Press the hole.

⑵. When the pipeline is stopped, due to molecular Brownian motion, small particles of impurities may enter the pressure tapping hole.

⑶. The system is frequently turned on and off. At the moment when the high-pressure zone is formed, small particles of impurities may enter the pressure tapping hole. Over time, it may cause blockage of the probe.

⑷. The medium contains a large amount of tar, algae organisms, or contains fibrous substances, which may also cause blockage of the probe.

6. Application of new technology

1. Make installation and maintenance simple.

2. Reduce the number of assembly parts and connect the hardware

Reduce costs.

Fast installation system

Quickly insert and unplug

● Sealed drive system can avoid damage to components

● Can be applied to the installation of multiple probes separately

Installation does not exceed 1 hour

2. Working principle

When the fluid flows through the probe, a high-pressure distribution area is generated in the front of the probe, and the pressure in the high-pressure distribution area is slightly higher than the static pressure of the pipeline. According to the principle of Bernoulli's equation, the fluid speeds up when flowing through the probe, and a low-pressure distribution area is generated at the back of the probe. The pressure in the low-pressure distribution area is slightly lower than the static pressure of the pipeline. After the fluid flows through the probe, a partial vacuum is generated at the back of the probe, and vortices appear on both sides of the probe. The cross-sectional shape of the uniform velocity flow probe, the roughness of the surface and the position of the low pressure tapping hole are the key factors that determine the performance of the probe. The stability and accuracy of the low-voltage signal play a decisive role in the accuracy and performance of the uniform velocity probe. Verabar's average velocity flow probe can accurately detect the average differential pressure produced by the average velocity of the fluid. Verabar's average velocity flow probe has multiple pairs of pressure holes arranged according to certain guidelines in the high and low pressure areas, making it possible to accurately measure the average velocity.

Verabar flowmeter measurement principle

Verabar flowmeter is a plug-in flow measuring instrument. Insert a Verabar sensor in the pipeline. When the fluid flows through the sensor, a high pressure distribution area is generated in the forward direction of the sensor, and a low pressure distribution area is generated at the back. The sensor has multiple pairs arranged according to a certain rule in the high and low pressure areas. Generally three pairs of pressure holes are used to measure the total pressure of the fluid, including the static pressure and the average velocity pressure Pl and the static pressure P2. Introduce P1 and P2 into the differential pressure transmitter respectively, and measure the differential pressure △P=P1-P2, △P reflects the size of the average velocity of the fluid, so that the flow rate of the fluid can be calculated.

三. Main technical indicators

1, Verabar flow measurement system performance indicators

Measurement accuracy: ± 1.5 Repeatability: ± 0.1

Applicable pressure: 0～40MPa Applicable temperature: -180℃～+550℃

Upper limit of measurement: Depends on the strength of the probe. Lower limit of measurement: Depends on the smaller differential pressure requirement of the measurement

Measuring range ratio: greater than 10:1

Applicable pipe diameter: 38mm～9,000mm round pipe, square pipe

Applicable medium: full pipe, one-way flow, one-way gas, steam and liquid with viscosity not more than 10 centipoise

Verabar has a wide range of applications. It is widely used in various gases, liquids and steam.

Steam measurement, the following is a typical application medium.

gas/liquid/steam

Natural gas/cooling water/saturated steam

compressed air/boiler water/superheated steam

gas/demineralized water

Gas Hydrocarbon/Liquid Hydrocarbon

Hot air/Cryogenic liquid

Furnace gas/Heat conduction liquid