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Electromagnetic flowmeter installation

Jan 22, 2019

Electromagnetic flowmeter installation

The installation of the electromagnetic flowmeter is especially important for the stable use of the electromagnetic flowmeter. How can we properly install the electromagnetic flowmeter? Below, Xi'an Huaheng Instrument introduces you:

First of all: after the fluid passes through the flow control valve, the fluid changes at the back end of the flow control valve, such as swirling, turbulence, etc. This is very influential for the measurement of the flowmeter, so usually the electromagnetic flowmeter will be installed in these valve bodies. Front end.

electromagnetic flowmeter


In addition: even if the valve body is fully open, most of the valves will make the straight pipe section at the front end of the flowmeter smaller, and the valve has a reduced diameter or even a curved passage. The electromagnetic flowmeter will not be damaged due to excessive flow.


The installation of the electromagnetic flowmeter is relatively simple. The diameter of the straight pipe section and the diameter of the electromagnetic pipe are the same as the flange diameter, the screw connection, the clamp connection, and the full pipe is guaranteed.


The measurement principle of the electromagnetic flowmeter does not depend on the characteristics of the flow. If there is a certain turbulence and vortex in the pipeline, it will be generated in the non-measurement zone (such as elbow, tangential current limit or half-opening shut-off valve upstream). Nothing. If steady-state eddy currents in the measurement zone affect the stability of the measurement and the accuracy of the measurement, then some measures should be taken to stabilize the flow rate distribution.


Electromagnetic flowmeter

Electromagnetic flowmeter installation for external installation requirements:


1. The electromagnetic flowmeter should not be installed in a place where the temperature change is compared. The environment with high temperature radiation cannot be installed. If it must be installed, it must have cooling measures and ventilation and ventilation equipment.


2. In the installation position of the electromagnetic flow, a relatively large space should be reserved to facilitate maintenance and post-maintenance.


3. The electromagnetic flowmeter should be avoided to be installed outdoors. If it must be installed, it should be safely protected against dripping, sunscreen, moisture, and waterproof lights.


4. The signal of the electromagnetic flowmeter is relatively weak, only 2.5~8mV at full scale, the flow is very small, the output is only a few microvolts, and the slight disturbance of the outside can affect the measurement accuracy. Therefore, the transmitter housing, shielded wire, measuring conduit, and tubing at both ends of the transmitter must be grounded.


5. The liquid should have the conductivity required for the measurement. It is also required that the conductivity distribution is substantially uniform. Therefore, the installation of the electromagnetic flowmeter should avoid the situation where the conductivity is not uniform, for example, the chemical liquid is added near the upstream, and the liquid addition point is preferably located downstream of the electromagnetic flowmeter, so that there is a better measurement effect.


6. The electromagnetic flowmeter measuring tube must be filled with liquid (except for non-full tube type). The electromagnetic flowmeter should be installed at any time to measure where the conduit can be filled with liquid to prevent an empty tube alarm due to the absence of liquid or tube in the measurement conduit.


7. The measuring tube of the electromagnetic flowmeter, the shield wire of the outer casing and the lead wire, and the pipe at both ends of the sensor must be reliably grounded, and must not be shared with the grounding of other electrical equipment. This is a special installation requirement of the electromagnetic flowmeter.


8. The electromagnetic flowmeter measuring tube is preferably installed vertically so that the liquid to be measured flows through the meter from bottom to top. In this way, it is possible to avoid measurement errors due to the presence of deposits in the conduit or bubbles in the medium. If it cannot be installed vertically, it can also be installed horizontally. But make the two electrodes on the same level.


9. The upstream of the electromagnetic flowmeter sensor should also have a certain straight pipe section, generally 5D~10D. The straight pipe section of the 5D after the first 10D must be guaranteed to avoid the measurement accuracy caused by the turbulent flow caused by the adjustment of the pipe inflection point and valve body.