Flow measurement using the differential pressure principle is the most widely used and most reliable flow measurement method in the world today. With the development of science and technology and the advancement of flow measurement technology, some new and high-performance measurement and sensing devices have gradually replaced the traditional Throttle device is used for flow measurement, and the new average speed flow probe, Verabar, introduced by VERIS, is one of them.
原理当流体流过探头时，在其前部产生一个高压分布区，高压分布区的压力略高于管道的静压。 First, the principle of Verabar flowmeter When fluid flows through the probe, a high-pressure distribution area is generated in 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.
Advantages of Verabar flowmeter:
High accuracy, large range ratio, greater than 10: 1; Non-constriction design, at least 95% lower than the permanent pressure loss of the orifice plate; Simple installation, only need to weld a base after opening a small hole in the pipe, no need Cut off the pipeline, some media can be installed online, and the probe can be taken out and inspected at any time, the installation cost is low, and the maintenance is basically free; because the connector of Verabar can be directly connected to the transmitter, three sets of valves and impulse pipes are not needed, which avoids Measurement errors caused by pressure leaks, blockages, etc .; It can measure various media such as gas, liquid, and vapor. It has a wide range of applications, and the measurement signal is stable and the fluctuation is small.
的设计、制造先进，但其测量系统对被测介质有关参数的准确性要求也非常高，这一点要比其它流量测量系统的要求严格得多。 The design and manufacturing of Verabar flowmeter is advanced, but its measurement system has very high accuracy requirements for the parameters of the measured medium, which is much stricter than other flow measurement systems.
Application areas of Verabar flowmeters
Verabar flowmeter adopts aerodynamic engineering structure design and manufacture. It has the advantages of high measurement accuracy, reliability, good stability, and small pressure loss. It can measure a wide range of fluids such as gas, liquid, steam and corrosive media. It is used for flow measurement in petroleum, chemical, natural gas, steel, power, chemical fiber, water supply and drainage industries.
应用极其广泛，流量测量技术与仪表的应用大致有以下几个领域： Verabar flowmeters are used in a wide range of applications. Flow measurement technology and instrumentation are used in the following areas:
First, the industrial production process
Flow instrument is one of the large-scale instruments in process automation instruments and devices.It is widely used in metallurgy, electricity, coal, chemical industry, petroleum, transportation, construction, light textile, food, medicine, agriculture, environmental protection and people's daily life. In various fields of the national economy, it is an important tool for developing industrial and agricultural production, saving energy, improving product quality, and improving economic efficiency and management. It occupies an important position in the national economy. Among the process automation instruments and devices, the flow meter has two major functions: as a detection instrument for the process automation control system and a total meter for measuring the quantity of materials.
Second, energy measurement
Energy is divided into primary energy (coal, crude oil, coal bed gas, petroleum gas and natural gas), secondary energy (electricity, coke, artificial gas, refined oil, liquefied petroleum gas, steam) and energy-bearing working fluids (compressed air, oxygen, Nitrogen, hydrogen, water). Energy measurement is an important means of scientifically managing energy, realizing energy saving and consumption reduction, and improving economic benefits. Flow meters are an important part of energy measurement instruments. Water, artificial gas, natural gas, steam, and oil products use an extremely large number of flow meters. They are indispensable tools for energy management and economic accounting.
Third, environmental protection projects
The discharge of smoke, waste liquid, sewage, etc. seriously pollutes the atmosphere and water resources, and seriously threatens the human living environment. The state has listed sustainable development as a national policy, and environmental protection will be the biggest issue in the 21st century. To control air and water pollution, management must be strengthened, and management is based on quantitative control of pollution.
China is a country with coal as its main energy source. There are millions of chimneys in the country that continuously emit smoke to the atmosphere. Flue gas emission control is an important project to eliminate pollution. Each chimney must be equipped with flue gas analysis instruments and flow meters to form a flail emission monitoring system. The flow rate and volume of the flue gas are very difficult. The difficulty is that the chimney is large in size and irregular in shape, the gas composition varies, the flow rate range is large, dirt, dust, corrosion, high temperature, no straight pipe sections, etc.
There are five ways: rail road, air, water, and pipeline. Although pipeline transportation has already existed for a long time, its application is not universal. With the prominence of environmental protection issues, the characteristics of pipeline transportation have attracted people's attention. Pipeline transportation must be equipped with a flow meter, which is the eye for control, distribution and dispatch, and an essential tool for safety oversight and economic accounting.
The 21st century will usher in the century of life sciences, and industries featuring biotechnology will develop rapidly. There are many substances to be monitored and measured in biotechnology, such as blood and urine. Instrument development is extremely difficult, with a wide variety.
Six, scientific experiments
The number of flowmeters required for scientific experiments is not only large, but also extremely diverse. According to statistics, a large part of more than 100 types of flowmeters are used for scientific research. They are not mass-produced and sold on the market. Many scientific research institutions and large enterprises have special teams to develop special flowmeters.
Seven, marine weather, rivers and lakes
These areas are open channels, and generally need to detect the flow velocity and then estimate the flow. The physical principle and fluid mechanics basis of the flowmeter and flowmeter are common, but the principle and structure of the instrument and the conditions of use are very different.