According to the flow meter structure classification (A) the characteristics of impulse flow meter instrument 1, the instrument itself has no wearing parts, easy installation, low maintenance. 2. The sticking material on the test plate will not affect the zero point and accuracy of the instrument, and zero drift will not occur. Impulse flow meter is a flow meter that continuously measures the solid material flow on the basis of the impulse principle. It can display the instantaneous flow and cumulative flow of the material flow.
(b) Mass Flowmeters Since the volume of a fluid is affected by parameters such as temperature and pressure, the volumetric flow rate is used to indicate the magnitude of the flow rate. In the case of continuous changes in the media parameters, it is often difficult to achieve this requirement, resulting in distortion of the instrument display value. Therefore, mass flow meters have been widely applied and valued. Mass flow meter is divided into direct and indirect two. The direct mass flow meter uses the principle directly related to the mass flow to measure. At present, there are mass flow meters such as calorimeter, angular momentum, vibratory gyroscope, Magnus effect, and Coriolis force type. An indirect mass flow meter uses a density meter and a volumetric flow rate to obtain a mass flow.
There are also various helium flow meters and trough flowmeters suitable for open channel flow measurement; plug-in flowmeters suitable for large-caliber flow measurement; laminar flowmeters for measuring laminar flow; and related to two-phase flow measurement Flowmeters; and laser, nuclear magnetic resonance flowmeters and a variety of tracer, dilution flow measurement, etc. (C) Ultrasonic flowmeters Ultrasonic flowmeters are based on the speed at which ultrasonic waves propagate in a flowing medium equal to the average of the measured medium. The geometrical principle of the flow velocity and the velocity of the acoustic wave itself is designed. It is also measured flow rate to reflect the size of the flow. Although ultrasonic flowmeters only appeared in the 1970s, it is popular because it can be made into a non-contact type and can be used to measure open flow in conjunction with an ultrasonic water level gauge. It does not generate disturbance or resistance to fluids. A very promising flow meter.
Classification of Ultrasonic Flowmeters: (1) Doppler Ultrasonic Flowmeter: Transducer 1 emits an ultrasonic signal with a frequency of f1. After passing through suspended particles or bubbles in the liquid in the pipe, the frequency shifts to the frequency of f2. Reflected to transducer 2, this is where Doppler will be, the difference between f2 and f1 is the Doppler frequency difference fd. Let the fluid velocity be v, the ultrasonic velocity be c, and the Doppler shift fd be proportional to the fluid velocity v. When the pipeline conditions, transducer installation position, launch frequency, and sound velocity are determined, c, f1, and θ are constants, and the fluid velocity is proportional to the Doppler shift, and the fluid velocity can be obtained by measuring the frequency shift. Find fluid flow. (2) Time difference ultrasonic flowmeter: Time difference ultrasonic flowmeter uses the principle that the time difference between sound propagation and countercurrent propagation in the fluid is proportional to the fluid flow rate to measure the fluid flow.
(d) Electromagnetic flowmeters are used in industry to measure the flow of media such as water and pulp. Measurable maximum pipe diameter of 2m, and minimal pressure loss. However, the medium with low conductivity, such as gas and steam, cannot be used. Electromagnetic flowmeters are expensive, and signals are susceptible to external magnetic fields, affecting widespread use in industrial pipe flow measurements. To this end, the products are constantly being updated and updated, and they are being developed into microcomputers. Electromagnetic flowmeter is the application of conductive body in the magnetic field to generate the induced electromotive force, and the induced electromotive force is proportional to the flow rate, by measuring the electromotive force to reflect the principle of the pipeline flow and made. Its measurement accuracy and sensitivity are high.
(5) Fluid Oscillating Flowmeters The fluid oscillating flowmeters are designed to use fluids that oscillate when they flow under specific flow conditions, and the oscillation frequency is proportional to the flow rate. When the flow cross section is constant, the flow rate is proportional to the flow volume of the lead volume. Therefore, the flow rate can be measured by measuring the oscillation frequency. This flow meter was developed and developed in the 1970s. Because it has the advantages of no rotating parts and pulsed digital output, it has a promising future. At present, typical products include vortex flowmeters and precession vortex flowmeters.
(b) Mass Flowmeters Since the volume of a fluid is affected by parameters such as temperature and pressure, the volumetric flow rate is used to indicate the magnitude of the flow rate. In the case of continuous changes in the media parameters, it is often difficult to achieve this requirement, resulting in distortion of the instrument display value. Therefore, mass flow meters have been widely applied and valued. Mass flow meter is divided into direct and indirect two. The direct mass flow meter uses the principle directly related to the mass flow to measure. At present, there are mass flow meters such as calorimeter, angular momentum, vibratory gyroscope, Magnus effect, and Coriolis force type. An indirect mass flow meter uses a density meter and a volumetric flow rate to obtain a mass flow.
There are also various helium flow meters and trough flowmeters suitable for open channel flow measurement; plug-in flowmeters suitable for large-caliber flow measurement; laminar flowmeters for measuring laminar flow; and related to two-phase flow measurement Flowmeters; and laser, nuclear magnetic resonance flowmeters and a variety of tracer, dilution flow measurement, etc. (C) Ultrasonic flowmeters Ultrasonic flowmeters are based on the speed at which ultrasonic waves propagate in a flowing medium equal to the average of the measured medium. The geometrical principle of the flow velocity and the velocity of the acoustic wave itself is designed. It is also measured flow rate to reflect the size of the flow. Although ultrasonic flowmeters only appeared in the 1970s, it is popular because it can be made into a non-contact type and can be used to measure open flow in conjunction with an ultrasonic water level gauge. It does not generate disturbance or resistance to fluids. A very promising flow meter.
Classification of Ultrasonic Flowmeters: (1) Doppler Ultrasonic Flowmeter: Transducer 1 emits an ultrasonic signal with a frequency of f1. After passing through suspended particles or bubbles in the liquid in the pipe, the frequency shifts to the frequency of f2. Reflected to transducer 2, this is where Doppler will be, the difference between f2 and f1 is the Doppler frequency difference fd. Let the fluid velocity be v, the ultrasonic velocity be c, and the Doppler shift fd be proportional to the fluid velocity v. When the pipeline conditions, transducer installation position, launch frequency, and sound velocity are determined, c, f1, and θ are constants, and the fluid velocity is proportional to the Doppler shift, and the fluid velocity can be obtained by measuring the frequency shift. Find fluid flow. (2) Time difference ultrasonic flowmeter: Time difference ultrasonic flowmeter uses the principle that the time difference between sound propagation and countercurrent propagation in the fluid is proportional to the fluid flow rate to measure the fluid flow.
(d) Electromagnetic flowmeters are used in industry to measure the flow of media such as water and pulp. Measurable maximum pipe diameter of 2m, and minimal pressure loss. However, the medium with low conductivity, such as gas and steam, cannot be used. Electromagnetic flowmeters are expensive, and signals are susceptible to external magnetic fields, affecting widespread use in industrial pipe flow measurements. To this end, the products are constantly being updated and updated, and they are being developed into microcomputers. Electromagnetic flowmeter is the application of conductive body in the magnetic field to generate the induced electromotive force, and the induced electromotive force is proportional to the flow rate, by measuring the electromotive force to reflect the principle of the pipeline flow and made. Its measurement accuracy and sensitivity are high.
(5) Fluid Oscillating Flowmeters The fluid oscillating flowmeters are designed to use fluids that oscillate when they flow under specific flow conditions, and the oscillation frequency is proportional to the flow rate. When the flow cross section is constant, the flow rate is proportional to the flow volume of the lead volume. Therefore, the flow rate can be measured by measuring the oscillation frequency. This flow meter was developed and developed in the 1970s. Because it has the advantages of no rotating parts and pulsed digital output, it has a promising future. At present, typical products include vortex flowmeters and precession vortex flowmeters.
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