Advantages and disadvantages of electromagnetic flowmeters in the water industry
The working principle of the electromagnetic flowmeter is based on Faraday's law of electromagnetic induction. In the electromagnetic flowmeter, the conductive medium in the measuring tube is equivalent to the conductive metal rod in the Faraday test, and the two electromagnetic coils at the upper and lower ends generate a constant magnetic field. When a conductive medium flows, an induced voltage is generated (the operation principle is as shown in the figure below). The two electrodes inside the pipe measure the induced voltage generated. The measuring tube is electromagnetically isolated from the fluid and the measuring electrode by a non-conductive inner liner (rubber, Teflon, etc.).
The functions of the electromagnetic flowmeter on the market are quite different. The simple one is to measure the one-way flow, and only output the analog signal to drive the rear position meter; the multi-function meter has the measurement bidirectional flow, range switching, upper and lower limit flow alarm, empty tube and power cut Alarm, small signal cutoff, flow display and total calculation, automatic check and fault self-diagnosis, communication with host computer and motion configuration. The serial digital communication function of some models can be selected from a variety of communication interfaces and dedicated chips (ASIC) to connect HART protocol system, PROFTBUS, Modbus, FF field bus and so on.
The electromagnetic flowmeter has a series of excellent characteristics that can solve the problems that other flowmeters are not easy to apply, such as the measurement of dirty flow and corrosion flow. In the 1970s and 1980s, electromagnetic flow had a major breakthrough in technology, and its application was very extensive.
advantage:
The measuring channel is a smooth straight pipe with no obstruction. It is suitable for measuring liquid-solid two-phase fluids containing solid particles, such as pulp, mud, sewage, etc.
Does not produce pressure loss caused by flow detection, good energy saving effect
The measured volumetric flow is virtually unaffected by changes in fluid density, viscosity, temperature, pressure, and conductivity;
Large flow range and wide range of caliber;
Corrosive fluids can be applied.
Disadvantages:
Cannot measure liquids with very low conductivity, such as petroleum products
Cannot measure gases, vapors, and liquids containing large bubbles
Cannot be used for higher temperatures.
Electromagnetic flowmeters are used in a wide range of applications. Large-diameter instruments are used in water supply and drainage projects. Small and medium-sized calibers are often used in high-demand or difficult-to-measure applications, such as steel industry blast furnace tuyere cooling water control, paper industry measuring pulp and black liquor, chemical industry. Strong corrosive liquid, pulp of non-ferrous metallurgical industry; small caliber, small caliber is often used in medical industry, food industry, biochemistry and other places with hygienic requirements.
Weed Mat Price,Garden Weed Mat,Nonwoven Weed Mat,Commercial Weed Mat
Henan Fengcheng Plastic Co.,ltd , https://www.fcsyplastic.com