Measuring principle of electromagnetic flowmeter
The principle of electromagnetic flowmeter measurement is based on Faraday's law of electromagnetic induction. The measuring tube of the flow meter is a non-magnetic alloy short tube lined with an insulating material. The two electrodes are fixed to the measuring tube through the tube wall in the tube diameter direction. The electrode tip is substantially flush with the inner surface of the liner. When the exciting coil is excited by the bidirectional square wave pulse, a working magnetic field having a magnetic flux density B is generated in a direction perpendicular to the axis of the measuring tube. At this time, if the fluid having a certain conductivity passes through the measuring tube, the cutting magnetic line induces the electromotive force E. The electromotive force E is proportional to the product of the magnetic flux density B, the inner diameter D of the measuring tube and the average velocity V. The electromotive force E (flow signal) is detected by the electrode and sent to the converter through the cable. After the converter amplifies the flow signal, it can display the fluid flow, and can output signals such as pulse and analog current for flow control and regulation.
Product advantage and preservation
The vortex flowmeter adopts micro-power high-tech, and can be operated continuously by lithium battery for more than one year, which saves the purchase and installation cost of cables and display instruments, and can display instantaneous flow and accumulated flow on the spot. The temperature-compensated integrated vortex flowmeter also has a temperature sensor that directly measures the temperature of the saturated steam and calculates the pressure to show the mass flow of the saturated steam. The temperature and pressure compensation integrated type has a temperature and pressure sensor. The gas flow measurement can directly measure the temperature and pressure of the gas medium, thereby indicating the volumetric volume flow of the gas.
In order to prevent accidental damage to the instrument, please keep the packaging status of our company when it is shipped to the user.
After the instrument arrives, it should be installed in time to avoid the insulation performance of the flow converter being reduced due to unexpected factors, and the metal parts are corroded. If you need to store for a long time, please observe the following:
1. When storing, try not to unpack.
2. The storage location should have the following conditions:
3. With rainproof and waterproof facilities
4. Not susceptible to mechanical vibration or shock
5. The instrument should be stored in the temperature and humidity ranges listed in the table below. The ideal temperature and humidity is 25 ° C, 65%
6. Ambient temperature -20 ° C ~ +60 ° C
7. Relative humidity 5% to 90%
Mass flow meter
Since the volume of the fluid is affected by parameters such as temperature and pressure, it is necessary to give the parameters of the medium when the flow rate is expressed by the volume flow. In the case of changing media parameters, it is often difficult to achieve this requirement, resulting in distortion of the meter display value. Therefore, mass flow meters have been widely used and valued. Mass flow meters are available in both direct and indirect versions. Direct mass flow meters are measured using principles directly related to mass flow. Currently used mass flow meters such as calorimetric, angular momentum, vibratory gyro, Magnus effect and Coriolis force. The indirect mass flow meter is obtained by directly multiplying the density meter by the volumetric flow rate to obtain the mass flow rate.
In modern industrial production, the operating parameters such as temperature and pressure of the flowing working fluid are continuously improved. In the case of high temperature and high pressure, due to the material and structure, the application of the direct mass flowmeter is difficult, and the indirect quality is encountered. Flowmeters are often not suitable for practical applications because they are limited by the range of humidity and pressure. Therefore, a temperature-pressure-compensated mass flowmeter is widely used in industrial production. It can be regarded as an indirect mass flow meter. Instead of using a density meter, it uses the relationship between temperature, pressure and density. It uses a temperature and pressure signal to calculate the density signal by function, and multiplies it by the volume flow. Mass Flow. At present, temperature and pressure-compensated mass flowmeters have been put into practical use. However, when the measured medium parameters vary widely or rapidly, it will be difficult or impossible to correctly compensate, so further study the mass flow rate applicable in actual production. Meters and densitometers are still a topic.
Chen's above-mentioned common structural principle of flowmeters is much better than various types of flowmeters, such as various helium flowmeters and trough flowmeters for open channel flow measurement; flowmeters suitable for large-caliber flow measurement; measuring laminar flow Laminar flowmeter; related flowmeter for two-phase flow measurement; and laser method, nuclear magnetic resonance flowmeter and various tracer methods, dilution method flow measurement, etc. With the development of technology and practical application needs, the new flowmeter will continue to emerge more types of flowmeters.