Differential pressure of dry gas seal in rich gas compressor
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Why is there a pressure difference between the main seal gas and the buffer gas?
““Rich gas” and “dry gas” are both local dialect terms; it’s better to use more standard terminology in this area. To guess the answer to your question: the sealing chamber within a compressor that requires sealing is composed of sealed air containing leaked gas, mixed exhaust gas, and dried sealed air (instrument air). The principle involves using a comb-toothed sealer, which is commonly used in dynamic seals, to prevent a portion of the sealed \"rich gas\" from entering the sealing chamber; there, it mixes with the sealed \"dry gas\" to form a gas mixture whose pressure is lower than that of the rich gas but higher than atmospheric pressure, and this mixture is then released into the atmosphere. The pressure generated in this mixing chamber prevents the leakage of \"rich gas,\" thus providing a certain degree of sealing effect. The specific pressure difference depends on the control requirements of the equipment. This is also one of the methods commonly used in ordinary dynamic sealing devices. It is recommended to look at the actual dismantled items to gain a better understanding. (For reference)
Back pressure, seal ring disengages from its working position