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Electromagnetic flowmeter output shaking check introduction

First, the cause of the failure
The output sloshing can be roughly summarized into five causes of failure, they are:
(1) The flow itself is fluctuating or pulsating, and it is not a malfunction of the electromagnetic flowmeter, but only reflects the flow condition truthfully;
(2) The end of the pipeline is filled with liquid or liquid containing bubbles;
(3) External stray current and other electrical and magnetic interference;
(4) Reasons for liquid physical properties (such as uneven liquid conductivity or slurry containing more granules/fibers);
(5) The electrode material is not properly matched to the liquid.
Second, the inspection procedures
Check the flow of the electromagnetic flowmeter output sloshing. First, make a preliminary investigation and judgment according to the comprehensive test of the process, and then carefully check and try to troubleshoot the problem one by one. The order of the inspection sequence listed in the process is: 1 can be observed or inquired to understand that it is not necessary to make a large operation, that is, it is easy to be difficult; 2 according to the past on-site maintenance experience, the frequency of occurrence is higher and the probability of occurrence may be higher in the future. The high is in front; 3 checks the requirements of their own. If a preliminary investigation confirms several reasons for the failure, it can also be carefully examined in advance.
1. Start--Check whether the piping of the electromagnetic flow sensor has a pulsating flow disturbance source--whether the flow power source is a reciprocating pump or a diaphragm pump.
Such as: a, add a gas chamber and a flow block to slow down the pulse
b, increase the amount of instrument damping
If no: Check if the downstream pump valve is hunting? If yes: improve control valve control characteristics
If no: Check if there are other sources of disturbance that produce fluctuations? If there is: there is a targeted source of interference removal. If not, please see 2.
2. Check if the liquid in the tube is full? Does the liquid contain bubbles? -- Set the air bag and manual exhaust valve downstream of the sensor for inspection and confirmation.
a. Check if the liquid in the tube is full? If it is not full: the sensor should be in a horizontal installation position or a vertical installation from the top to the bottom of the position should pay special attention to change to a fully full position, such as vertical installation from bottom to top.
b. Does the liquid contain bubbles? If there are air bubbles: Install other separators or automatic exhaust valves upstream of the sensor. If there is no bubble, please see 3.
3. Check if the sensor is well grounded?
If there is no good grounding: a, sensor and adjacent pipeline to achieve a third grounding (less than 100 ohms)
b. When connecting and insulated pipes or anti-corrosion lining pipes, install a grounding ring or a grounding short pipe at both ends of the sensor.
If the grounding is good, check the pipeline for interference such as stray current. If there is interference with mobile interference sources.
If there is no interference, check if there is a strong magnetic field source such as a large power transformer near the sensor. If so, change the installation position, the principle of strong magnetic field source.
4, check the physical properties of the liquid - whether it is a slurry - whether the liquid conductivity is uniform - whether the liquid conductivity is too low.

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