What pressure and flow rate are appropriate for a pneumatic level gauge?
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What pressure and flow rate are appropriate for a pneumatic level gauge? The goal is to achieve a pipeline pressure that is roughly equal to the pressure at the bottom of the liquid level; the flow rate should be limited so that not too much air is introduced, just a few bubbles being sufficient.
I haven’t used this level gauge yet; looking forward to great answers from others.:P
For a purge-type level gauge, the pressure must be higher than that at the bottom of the liquid; typically, instrument air is used as the purge gas source. The key is to control the flow rate of the purge gas – it is sufficient to ensure that a small amount of bubbles continuously escape
For an air-operated level gauge, the appropriate pressure depends on the height of the liquid at full level. If it’s a container with an open top and 3 meters in height, and the medium is water, then the pressure would be 30 KPA; therefore, a pressure slightly above 30 KPA is sufficient. As for flow rate, there is usually a regulator available. If no regulator is present, a throttle orifice plate can be used to maintain a stable flow rate. During operation, it’s sufficient to ensure that bubbles emerge continuously and evenly.
There are no strict requirements regarding the flow rate of the air blown out; as long as bubbles are formed, that’s sufficient. It mainly ensures that the air pressure supplied for positive and negative pressure testing is the same; any difference can lead to errors