工作原理简介 Introduction to the working principle of Verabar flowmeter
When fluid flows through the probe, a high-pressure distribution area is created 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, when the fluid flows through the probe, the speed increases, and a low-pressure distribution area is generated at the rear 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 created at the back of the probe, and vortices appear on both sides of the probe. The cross-sectional shape of the average velocity flow probe, the surface roughness, and the location of the low pressure pressure taking 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 average speed 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 taking holes arranged according to certain criteria in the high and low pressure areas, making it possible to accurately measure the average flow rate. Verabar flowmeters always maintain the leading position in plug-in flowmeters with its unique advantages. The advantages. Verabar flowmeter is basically suitable for the measurement of all pipeline specifications on the site. The application on large-diameter pipelines shows even more advantages. It is suitable for measuring the flow of various liquids, gases, and steam, especially ultra-low temperature, high temperature, high pressure, and humid fluid Measurement of media. However, while the application is being promoted, customers will also encounter the same questions about how to maintain. A brief summary of the work and simple maintenance of Verabar flowmeters before commissioning:
1. Check the installation of the flow meter: After completing the installation of the Verabar flowmeter, it must be carefully inspected, and the welding must be firm, the direction is correct, and the pressure test has no leakage. 2. Instrument calibration: Read the manual of the intelligent flow totalizer carefully. According to the calculation book attached to the Verabar flowmeter, set the parameters in the intelligent flow totalizer correctly to ensure that the totalizer can correctly calculate and display the flow. If you are directly on the computer, you need to set the input data format and corresponding compensation methods in the computer. 3. Instrument wiring is correct: Verabar flowmeter, differential pressure transmitter, and flow totalizer constitute a measurement system. Please check repeatedly to make sure that it is correct. Rear can be put into operation. 4. System warm-up: After the preparation for commissioning is completed, the measured medium fills the process pipeline, and the Verabar flowmeter is temporarily closed. At this time, the balance valve of the three valve group should be opened, and the high pressure valve and low pressure valve should be closed. status. Power on the instrument and warm up for 15 minutes. 5. System operation: After the preheating is completed, open the high-pressure valve and low-pressure valve of the three-valve group, fill the differential pressure transmitter with the measured medium, open the drain valve behind the differential pressure transmitter, and quickly discharge the dirty liquid or gas. Close the blowdown valve and then close the balance valve of the three-valve group. The transmitter will enter the measurement state and the flow totalizer will also enter the working state to display the medium flow in the pipeline. The most advanced differential pressure flow measurement technology Y-HLV Veribar flowmeter uses an engineering structure design that fully complies with the principle of aerodynamics. It is a sensor element that has achieved unparalleled levels of accuracy, efficiency and reliability. . 1, Verabar flowmeter uses GY-HLV Verabar flowmeter is suitable for high-precision flow measurement of gas, liquid and steam. Verabar is a differential pressure, rate average flow sensor, which measures the flow through the differential pressure generated by the sensor in the fluid. Verabar reflects the true flow velocity of the fluid, with an accuracy of ± 1.0 and repeatability of ± 0.1. The outstanding advantages of Verabar are: output a very stable, pulsation-free differential pressure signal2, probe design features Probes with a cross-sectional shape of the bullet head can produce accurate pressure distribution, fixed fluid separation points; located on the two sides behind the probe side, the fluid The low-pressure tapping hole before the separation point can generate a stable differential pressure signal and effectively prevent blockage. The internal integrated structure can avoid signal leakage, improve the structural strength of the probe, and maintain long-term high accuracy. 3. Veribar probe anti-blocking design With its excellent anti-blocking design, the Veribar flow probe completely eliminates the shortcomings of plug-in flow probes such as Annubar. the height of. The high-pressure pressure taking hole of the probe will not be blocked by the front of the probe to form a high-pressure area. The pressure is slightly higher than the static pressure of the pipeline, which prevents particles from entering. Please note: The velocity of the fluid at the probe's high-pressure tapping hole is zero, and no objects will enter the tapping hole. When the machine is turned on, the fluid enters the elbow under the static pressure of the pipeline, and a pressure equilibrium state is quickly formed. When the pressure equilibrium state is formed, the fluid encounters high pressure at the inlet of the elbow, detours, and no longer enters the elbow.
4. Advantages of the probe ● It can measure a variety of media and has a wide range of applications ● High accuracy and large range ratio ● The probe's pressure hole is essentially anti-blocking ● The measurement signal is stable and the fluctuation is small ● The permanent pressure loss of the pipeline is low ● The unique high-strength bullet Head-shaped single-chip dual-cavity structure ● Low installation cost and basically maintenance-free ● Can be installed and repaired online
5. Characteristics of Verabar averaging tube flow sensor ● Stable signal Verabar's low-pressure pressure taking holes are located on the back of the probe side, between the fluid and the probe separation point, and away from the vortex fluctuation area.
● Excellent long-term high-precision Verabar can guarantee long-term stability of accuracy, because:
⑴. It is not affected by abrasion, dirt and oil.
⑵. There are no moving parts in the structure.
⑶. The occurrence of blockage is excluded from the design. At the front of the probe, a high static pressure area surrounds the probe so that the high-pressure pressure taking hole will not be blocked. The most important thing is that the low-pressure holes are taken at the back two sides of the probe side, and the fluid is swept across the surface, which protects the low-pressure holes from being swept, and other probes are easily blocked because their low-pressure pressure holes are collected by impurities. Low voltage fluctuation area.
● Lowest installation cost ⑴. It only needs a few inches of line welding, and the installation is very simple and fast.
⑵. Apply special tools to achieve online installation with pressure.
⑶. All valves and interfaces of various instruments need only simple assembly, which requires very low assembly costs.
的运行费用是最低的。 ● Very low operating cost. It is a non-restrictive design. As a plug-in flow probe, Verabar flowmeter has the lowest operating cost.
威. Verabar flowmeters only produce very low permanent pressure losses, typically less than 0.7KPa
⑶. The permanent pressure loss generated by an orifice plate element exceeds 14KPa
⑷. Compared with the orifice plate, Verabar's energy loss is reduced by 95%.
● The continuous operation of Verabar basically eliminates the possibility of clogging, but in the following cases, Verabar still needs to pay attention to the clogging:
⑴. When the impulse tube leaks and the high pressure balance area of the probe is damaged, particles with smaller diameters in the impurities may enter the pressure taking hole.
⑵. When the pipeline is stopped, due to the Brownian motion of the molecules, small particles of impurities may enter the pressure taking hole.
⑶. The system frequently starts and stops. At the moment when the high-pressure area is formed, small particles of impurities may enter the pressure taking hole. Over time, the probe may be blocked.
⑷. The medium contains a large amount of tar, algae, or contains fibrous substances, which may also cause the probe to be blocked.
6, the application of new technology unique design of valve joints with valve ... New design concept provides a new concept, built-in instrument stop valve at the connector of the instrument
1. Make installation and maintenance easier.
2. Reduce the number of assembly parts and reduce the cost of hardware connection.
Quick installation system Quick insertion and removal ● Sealed drive system can avoid damage to components ● Can be applied to the installation of multiple probes separately All installations take less than 1 hour
Main technical indicators of Verabar flowmeter
1. Performance index of Verabar flow measurement system Measurement accuracy: ± 1 Repeat accuracy: ± 0.1
Applicable pressure: 0 ～ 40MPa Applicable temperature: － 180 ℃ ～ ＋ 550 ℃
Upper measurement limit: Depends on the probe strength. Lower measurement limit: Depends on the minimum differential pressure required. Range ratio: greater than 10: 1
Applicable pipe diameter: 38mm ～ 9,000mm Round pipe and square pipe Applicable medium: full pipe, one-way flow, one-way gas, steam, and liquid Verabar with a viscosity not greater than 10 centipoise It is widely used for the measurement of various gases, liquids and vapors. The following are typical application media.
Verabar flowmeter measurement principle
是一种插入式流量测量仪表。 GY-HLV Verabar flowmeter is a plug-in flow measurement instrument. A Verabar sensor is inserted in the pipeline. When the fluid flows through the sensor, a high-pressure distribution area is generated in the forward flow direction of the sensor and a low-pressure distribution area is generated at the rear. The sensor has a plurality of pairs of pressure-receiving holes arranged in a certain rule in the high and low pressure regions, and generally measures 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 to the differential pressure transmitter respectively, and measure the differential pressure △ P = P1-P2. △ P reflects the average velocity of the fluid, so that the flow rate of the fluid can be calculated.