What are the common faults of split electromagnetic flowmeters?

Case introduction

After initial debugging and normal operation for a period of time, the split electromagnetic flowmeter failed during operation. Common causes of failure are: internal flow sensor connection layer, lightning strikes, and environmental changes. The flowmeter staff below will lead everyone to understand some common faults about split electromagnetic flowmeters.

1. Internal connection layer flowmeter manufacturers understand that because split electromagnetic flowmeters have a greater chance of measuring suspended solids or internal dirt than any other flow meter, the internal connection layer appears The failure efficiency is relatively high. If the conductivity and liquid conductivity adhesion layers are tight, the instrument can still output normal signals, but the circulation area is changed, forming a hidden fault in the measurement error; if there is a high conductivity adhesion layer, the electromotive force between the electrodes will be short-circuited; if the insulation layer Connect, insulate electrode surfaces and break circuits. Both phenomena can make the instrument unable to work.

2. Lightning strike: Internal electricity strikes the circuit and induces high voltage and transient surge current, which may damage the instrument if it reaches the instrument.

Lightning strikes damage instruments in three ways: power lines, excitation signals between sensor spoon converters, and flow lines. However, other ways of analyzing the failure of various components from lightning strike damage to the introduction of high voltage and surge current from the power supply circuit in the control room lead to failure. The split-type electromagnetic flowmeter not only failed due to lightning strikes at the accident site, but also other electrical instruments in the control room often suffered lightning strikes at the same time. Therefore, the user unit knows the importance of power line control room instruments and lightning protection facilities. If the current existing general and exploratory design unit teams address this issue.

3. Changes in environmental conditions When the fault environment occurs during the debugging stage, there are not only interference sources that appear during debugging and interference during operation. For example, ground fault protection is not ideal, and split electromagnetic flowmeters, During debugging, there is no air source plant and the equipment works normally, but during operation, new interference sources (such as spot tubes or near-far tube welding implementation) interfere with the normal operation of the instrument, and the output signal experiences large fluctuations.