The flowmeter has a wide range of applications and many classifications. We will analyze the flowmeter in detail.
The development of flow measurement can be traced back to ancient water conservancy projects and urban water supply systems. In the Roman caesar era, orifice plates were used to measure the drinking water of residents. Weir method was used in ancient Egypt around 1000 BC to measure the discharge of the Nile. The well-known Dujiangyan water conservancy project in China uses the water level of the treasure bottle mouth to observe the amount of water and so on. Flow meters are divided into rotor flow meters , throttle flow meters , fine slit flow meters , volume flow meters , electromagnetic flow meters , ultrasonic flow meters and so on.
In the 17th century, Torri demolition laid the theoretical foundation for differential pressure flow meters , which is a milestone in flow measurement. Since then, the prototypes of many types of meters for flow measurement in the 18th and 19th centuries have begun to form, such as weirs, tracers, pitot tubes, venturis, volumes, turbines, and target flow meters. In the 20th century, due to the rapid increase in the demand for flow measurement in process industry, energy measurement, and urban utilities, the rapid development of meters was promoted. The rapid development of microelectronics and computer technology has greatly promoted the upgrading of meters, and new flowmeters have sprung up like mushrooms. . So far, it is said that hundreds of flowmeters have been put on the market, and many difficult problems in field use are expected to be solved.
It is relatively late to carry out modern flow measurement technology in China, and the flow meters required in the early days are imported from abroad.
Flow measurement is the science that studies the change of mass. The law of mass change is the basic law of the development of the relationship between things. Therefore, its measurement object is no longer limited to the traditional pipeline liquid. There is a problem of flow measurement wherever the volume change needs to be mastered. Flow, pressure and temperature are listed as the three major detection parameters. For a certain fluid, as long as these three parameters are known, the energy can be calculated, and these three parameters must be detected in the measurement of energy conversion. Energy conversion is the basis of all production processes and scientific experiments, so flow, pressure, and temperature instruments are the most widely used. HVAC Online
Application fields of flow meter:
The application of flow measurement technology and instrumentation generally has the following areas.
An 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. HVAC-air conditioning-online
Second energy measurement
Energy is divided into primary energy (coal, crude oil, coalbed methane, 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), etc. 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. nuantongkongtiaozaixian
Three 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.
An instrument used to measure the fluid flow (volume of fluid passing in a unit time) in a pipeline.
There are many types of flow measurement methods and instruments, and many classification methods. So far, there are as many as 60 types of flow meters available for industrial use. The reason why there are so many types is that no flow meter has been found that is suitable for any fluid, any range, any flow state, and any use conditions.
These more than 60 kinds of flow meters, each product has its specific applicability, but also has its limitations. According to the measurement object, there are two categories: closed pipes and open channels. According to the purpose of measurement, it can be divided into total measurement and flow measurement. The instruments are called total meters and flow meters.
The total meter measures the flow through the pipeline over a period of time. It is expressed by the quotient of the total flow flowing in a short time divided by the time. In fact, the flow meter usually also has a cumulative flow device for the total meter. The total meter is also equipped with a flow signalling device. Therefore, it is no longer practical to separate flow meters and total meters in a strict sense.
According to the measurement principles, there are mechanical principles, thermal principles, acoustic principles, electrical principles, optical principles, and atomic physics principles.
According to the most popular and widely used classification method at present, it is divided into: volumetric flowmeter, differential pressure flowmeter, float flowmeter, turbine flowmeter, electromagnetic flowmeter, vortex flowmeter in fluid oscillation flowmeter, quality Flowmeters, plug-in flowmeters, and probe-type flowmeters are used to explain the principles, characteristics, application overview, and domestic and foreign developments of various flowmeters.
According to the principle of flowmeter mechanism, there are volume flowmeter , impeller flowmeter , differential pressure flowmeter , variable area flowmeter , momentum flowmeter , impulse flowmeter , electromagnetic flowmeter , ultrasonic flowmeter and mass flowmeter. , Fluid oscillation type flowmeter .
This article comes from: Jiangsu Dongxiang Instrument Co., Ltd. News