概述最先进的差压式流量测量技术 I. Overview of Verabar FlowmetersThe most advanced differential pressure flow measurement technology
The XD-HLV Verabar flowmeter uses an engineering structure design that fully complies with aerodynamic principles. It is a sensor element that has achieved unparalleled levels of accuracy, efficiency and reliability.
1, Verabar flowmeter uses
XD-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 advantage of Verabar is: output a very stable, pulse-free differential pressure signal
2. Design characteristics of the probe The probe with a cross-sectional shape of the bullet head can produce accurate pressure distribution and a fixed fluid separation point; the low-pressure pressure taking holes located on the two sides behind the probe side and before the fluid separation point can generate a stable differential pressure signal, and Effective anti-blocking. The internal integrated structure can avoid signal leakage, improve the structural strength of the probe, and maintain long-term high accuracy.
3. Verabar probe anti-clogging design Verabar flow probe with its excellent anti-clogging design completely eliminates the shortcomings of plug-in flow probes such as Annubar. height.
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.
● Very low operating cost. It is a non-constricting design. As a plug-in flow probe, Verabar has the lowest operating cost.
只产生非常低的永久性压力损耗，典型的少于0.7KPa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, all installed within less than 1 hour 2. Main technical indicators of Verabar flowmeters
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.
Gas / Liquid / Steam Natural Gas / Cooling Water / Saturated Steam Compressed Air / Boiler Water / Superheated Steam Gas / Demineralized Gas Hydrocarbon / Liquid Hydrocarbon Hot Air / Low Temperature Liquid Generator Gas / Heat Conductive Liquid Brief introduction of working principle When fluid flows through the probe, a high-pressure distribution area is generated at the front of the probe. 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. The Verabar 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 velocity.
Four, Verabar flowmeter measurement principle
是一种插入式流量测量仪表。 XD-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.