How to maintain and maintain the electromagnetic flowmeter under shutdown
When the electromagnetic flowmeter is not used when it is shut down, we must take scientific and reasonable maintenance and maintenance methods for the electromagnetic flowmeter. In the electromagnetic flowmeter technical service for the user, it is often encountered that the user uses the electromagnetic flowmeter for a period of time after using the electromagnetic flowmeter for re-use to find the measurement data inaccurate. In fact, this is not a quality problem in the electromagnetic flowmeter itself. Because the user did not follow the maintenance and maintenance methods in the manual. electrical monitoring window,cable junction box,waterproof enclosure,Network enclosure wybox inc. , https://www.wybox-inc.com
First, the zero point inspection and adjustment of the electromagnetic flowmeter maintenance:
Before the electromagnetic flowmeter is put into operation, after the power is turned on, the zero point must be adjusted when the electromagnetic flow sensor is full of liquid. After the operation, it is necessary to check the periodic stoppage of the use conditions for zero check; especially for sedimentation and contamination of the electrode, the non-cleaning liquid containing the solid phase should be inspected at the initial stage to obtain the experience to determine the normal inspection cycle. The AC excitation type electromagnetic flowmeter and the rectangular wave excitation ratio are more prone to zero drift, so it is necessary to pay attention to inspection and adjustment.
An example of an application error that causes two layers to fail. One is the oil drilling and cementing project. The total flow of cement slurry is an important process parameter, often using a high-pressure electromagnetic flowmeter. The meter is used intermittently. After use, rinse the sensor measuring tube with clean water, and the rest of the time is empty. Due to incomplete cleaning, the residual cement slurry on the inner wall of the measuring tube is solidified into a thin layer, which accumulates in the past two months to form an insulating layer, covering the entire surface of the electrode, resulting in abnormal operation and eventually failure to work.
The other is the electrolytic cutting process inspection device, which uses an electromagnetic flowmeter to control the flow rate of saturated brine. After a period of use, the flow signal is gradually weakened. The reason is that iron oxide is deposited on the wall of the tube during electrolytic cutting, resulting in a short circuit. Clearing the stratification immediately returns to normal.
Second, the electromagnetic flowmeter maintenance periodic inspection sensor electrical performance:
First, the resistance between the electrodes is roughly measured. Disconnect the signal between the sensor and the converter. The sensor is filled with liquid. Use a multimeter to measure the resistance of the two electrodes and the ground. It is within the specified range of the manufacturer and the measured values ​​are roughly the same. Record the resistance value measured for the first time. This value is useful for determining the cause of the sensor failure (such as whether the deposited layer is conductive or insulated).
Next, the sensor is emptied of liquid, and the inner wall is wiped clean. After it is completely dried, the resistance between the two electrodes and the ground terminal is measured with a megaohm meter.
Finally, check the insulation resistance of the excitation coil, remove the sensor excitation coil, connect the terminal to the converter, and measure the insulation resistance of the coil with a megaohm meter.