Electromagnetic flowmeter
Main advantages: (1) Because the measurement channel is a section of smooth straight pipe, it will not be blocked, especially for solid particles of liquid-solid two-phase fluids, such as pulp, sewage, slurry, etc.; (2) No pressure loss, energy saving effect; (3) Not affected by changes in the fluid's humidity, density, viscosity, pressure, and electrical conductivity; (4) Wide range of flow rate, wide range of caliber; (5) Applicable to the measurement of corrosive fluids.
Disadvantages: (1) not applicable to the measurement of petroleum products released by the fluid; (2) not applicable to high temperature occasions.
Electromagnetic flowmeter has been widely used in industrial production sites, such as large diameter industrial water supply and drainage, small diameter conductive liquid, dirty flow, corrosive flow, slurry and other media measurement occasions. But it can not measure the conductivity of the liquid is very low (such as petroleum products), can not measure the gas, steam and contains large bubbles of liquid, can not adapt to higher temperature environment. Electromagnetic flowmeter cost is high, and the signal is susceptible to external magnetic field interference, special attention should be paid to equipment grounding and lightning protection measures.
Vortex flowmeter
Vortex flowmeter is based on the principle of Kamen vortex made of a fluid oscillatory flow. That is, in the fluid placed a non-streamlined vortex generator, the fluid in the vortex generator downstream on both sides of the vortex generator to produce two columns of regular vortex that is Carmen vortex, vortex speed and fluid speed into a certain ratio, so as to calculate the volume flow.
Main advantages: (1) simple and solid structure, easy to install; (2) wide range of applications, suitable for multi-fluid media; (3) high measurement accuracy; (4) wide measurement range, and small pressure loss, no moving parts, high reliability.
Disadvantages: (1) not adapted to low Reynolds number of fluid measurement; (2) the need for a longer straight section; (3) compared with the turbine flowmeter, the instrumentation factor is lower.
The vortex flowmeter is suitable for measuring liquids, gases or vapors. It has no moving parts and no fouling problems. Vortex flowmeters produce noise and require the fluid to have a high flow velocity to produce vortices. Vortex flowmeter is mainly used in industrial production pipeline media fluid flow measurement. In the measurement of the working volume flow rate is almost independent of the fluid density, pressure, temperature, viscosity and other parameters. Instrument parameters can be stabilized for a long time, the field application of high reliability, low maintenance.
Ultrasonic flowmeter
ultrasonic flowmeter without internal flow winding and fluid pressure loss for non-contact flow measurement of the typical flowmeter, ultrasonic flowmeter and electromagnetic flowmeter belongs to the structure of the unimpeded fluid DC.
Main advantages: (1) can do non-contact fluid measurement; (2) belongs to the non-impediment measurement, so no pressure loss; (3) it has the advantages of measuring non-conductive liquids compared to electromagnetic flow meter.
Disadvantages: (1) propagation time method can only be used for single-phase clean liquids and gases, while the Doppler method of measuring liquids containing a certain amount of suspended particles and bubbles; (2) Doppler method of measurement accuracy is not high.
Ultrasonic flowmeter is an instrument for measuring volume flow without obstruction. It is applicable to almost all liquids in industrial production, including slurry, with high accuracy. Particularly suitable for solving the difficult occasions of flow measurement, especially for large mouth diameter flow measurement field.
Ultrasonic flowmeter requires relatively clean fluid. Pipeline fouling will affect the accuracy. Ultrasonic flowmeter is more and more widely used in industrial production, because it can effectively measure the flow of natural gas. This measurement is non-insertion and does not cause pressure loss.