Dry gas seal issues in mechanical pumps
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I have a gentle question: if the seal for a mechanical pump is a dry gas seal, what is usually used as the medium? And in the case of a liquefied gas pump, is nitrogen used as the sealing medium? A dry gas seal consists of an air film directly between the stationary ring and the rotating ring. So, will this gas membrane break? Will dry gas keep being supplied? Then, does the additional dry gas flow into the medium or outside the pump? Please let me know if you know, thanks
Dry gas seals typically use nitrogen or other dry, clean gases as the sealing medium. For liquefied gas pumps, nitrogen is indeed commonly used because it has stable chemical properties and does not react with liquefied gas. The air film in a dry gas seal should not break; its function is to isolate or reduce the leakage of the medium by maintaining a certain air gap. If the seal is properly designed and maintained, this layer of gas film can remain intact without breaking. As for the supplementary dry gas, it mainly flows into the sealing system of the pump to maintain an air film, rather than flowing into the medium or outside the pump. The sealing system is designed with certain control and monitoring devices to ensure that gas flow and pressure remain within safe and effective ranges. .
It is recommended to get a structural diagram of the pump, as that will make things clear at a glance. Typically, the gas seals of such pumps use the leakage gas from the medium inside the pump for sealing; the mixture formed when the sealing gas enters the seal is then either released into the atmosphere or directed to a collection chamber for processing. There should be a certain ratio between the pressure of the sealing gas and the pressure of the medium inside the pump; in some cases, self-regulating valves are used for this purpose, for reference only.
1. The choice of sealing gas has no impact on the manufacturing process; any gas that does not affect product quality can be used as a sealing gas； 2. The medium gas is generally used for the main sealing gas