涡轮流量计 4.Turbine flowmeter
The turbine flow meter uses a multi-blade turbine rotor to sense the average speed of the fluid, and derives the flow or total meter; it consists of two parts: a sensor and a display.
The advantages of turbine flowmeters are: accurate flow measurement, good renaturation, zero drift, strong interference ability, wide range and compact structure.
The disadvantages of the turbine flowmeter are that it cannot maintain calibration characteristics for a long time, and physical properties have a large impact on flow characteristics.
Turbine flowmeters are widely used in the measurement of organic liquids, petroleum, inorganic liquids, natural gasification gas, and low-temperature circulation.
5. Electromagnetic Flowmeter
The electromagnetic flowmeter uses Faraday's law of electromagnetic induction to measure the flow velocity, and then uses some method to measure the liquid level of the cross section of the flow to obtain the flow area. Multiply the two to obtain the flow.
The electromagnetic flowmeter has a series of excellent characteristics, which can solve the problems that other flowmeters cannot easily solve, such as the measurement of dirty and corrosive flows.
The advantages of the electromagnetic flowmeter are: the measurement channel is a smooth straight tube and it will not be blocked. It is suitable for measuring liquid-solid two-phase fluids containing solid particles, such as pulp, mud, sewage, etc .; no pressure loss caused by flow detection, The energy saving effect is good; the measured volume flow is actually not significantly affected by changes in fluid density, viscosity, temperature, pressure, and conductivity; the flow range is wide and the caliber range is wide; it can be applied to corrosive fluids.
Disadvantages of electromagnetic flowmeters: cannot measure liquids with very low conductivity, such as petroleum products. Capable of measuring gases, vapors, and liquids with large bubbles; cannot be used at higher temperatures. The electromagnetic flowmeter has a wide range of applications, and large-caliber meters are mostly used in water supply and drainage projects; small- and medium-caliber meters are often used in high-requirement or difficult-to-measure applications, such as cooling water control in the blast furnace tuyere of the iron and steel industry, measuring pulp and black liquor in the paper industry, and chemical industry Strong corrosive liquid, non-ferrous metallurgy industry slurry; small-caliber and micro-caliber instruments are often used in places with health requirements such as the pharmaceutical industry, food industry, biochemistry.
In the 1970s and 1980s, electromagnetic flowmeters made major breakthroughs in technology, making it a widely used type of flowmeter, and the usage rate has continued to rise.
涡街流量计 6. Vortex flowmeter
A vortex flowmeter is a meter in which a non-streamline vortex generator is placed in a fluid, and the fluid alternately separates on both sides of the generator to release two series of regularly staggered vortex generators.
According to the frequency detection method, it can be divided into stress type, strain type, capacitive type, thermal type, vibrating body type, photoelectric type, and ultrasonic type. They are the youngest type of flowmeters, but they have developed rapidly and have become universal. A type of flow meter.
Disadvantages of vortex flowmeters: Not suitable for low Reynolds number measurement, long straight pipe sections, low table coefficient (compared to turbine flowmeters), and lack of application experience in pulsating flow and multiphase flow.
优点：结构简单牢固、用流体种类多、度较高、围度宽、损小。 The vortex flowmeter has the advantages of simple and firm structure, many types of fluids, high degree, wide range, and small loss.
To be continued