Migration problem of venturi differential pressure flow meters
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When migrating a Venturi differential pressure flow meter, should it be done when there is no pressure in the pipeline or when there is pressure? In my opinion, it is more accurate to carry out the migration when there is pressure in the pipeline.
This post was last edited by jujiangliu on 2015-7-30 10:26. Do flow meters need to be migrated? I’ve only heard that differential pressure level transmitters require zero-point adjustment. In fact, modern smart meters simply allow for the direct setting of the zero point and range; this is different from the concept of zero-point adjustment used in DDZ-II and DDZ-III type meters.
Migration should be carried out in the initial state; the level should be zero, with no adjustments made when it is not zero.....
However, since there is no flow of medium in the pipeline, the flow meter indicates whether action is needed
If a positive pressure is indicated when there is no fluid in the pipeline, then corresponding negative migration should be carried out； If a negative pressure value is displayed, then corresponding positive migration must be carried out.
It seems there is no flow of medium; theoretically, the transmitter should not indicate any value, as the positive and negative pressures are equal. If a small value is shown, it can be zeroed out. If a large value appears, the cause of that pressure should be identified
Should the migration be carried out when there is pressure in the pipeline or when there is no pressure? Why does the flow meter show errors when there is no flow in the medium, but no deviation once it starts operating? It is measuring the same medium in the same pipeline
What is a medium? Gas/liquid? Is the venturi installed in a horizontal or vertical pipe?
The medium is gas (oxygen), and it is installed in a horizontal pipeline.
The zero drift of the transmitter can be reset; no issues have been encountered so far with flow meter drift
The flow meter does not need to be relocated. When measuring gas, it’s like this: it’s normal for there to be a reading even when there is no flow. What you need to do is remove those numbers from it.