Dry gas seal
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I have two questions for experts: 1. For a series-type dry gas seal, regarding the primary sealing gas and the secondary sealing gas, what are the potential hazards if the secondary sealing gas is introduced first? 2 Why should the intake flow rate of the secondary seal be slightly less than the leakage rate of the primary seal? How is it determined?
1. It is possible to damage the main seal, as well as the sealing ring between the seal sleeve and the shaft. 2. During normal operation, no air should enter the second stage; if the amount of air entering the second stage exceeds the leakage rate from the first stage, it will be impossible to detect any leaks in the first-stage seal. As I understand it, in a series dry gas seal system, once a leak occurs, it is vented through the flare gas pipeline to keep the pressure in the secondary seal chamber at a stable level during normal operation; usually, there is a pressure gauge available for accurate monitoring of this pressure
In my opinion: 1. It shouldn’t have any impact； 2. The dry gas seal is equipped with a flow meter for monitoring
"1. It is possible to damage the main seal, as well as the sealing ring between the seal sleeve and the shaft. Why?
In a series dry gas seal, the secondary sealing gas is originally the leakage gas from the primary seal – how can it be put into use first? In a tandem dry gas seal, the secondary sealing gas is only a portion of the leakage gas from the primary seal; therefore, its flow rate should also be less than that of the leakage from the primary seal
1. Generally, secondary gas uses process gas; primary gas is used to isolate the process gas, while secondary gas serves to counteract the effect of primary gas. The latter is intended to prevent oil from entering the cylinder, and it should be activated 30 minutes before the oil system is started up
Increasing the axial force on the sealing sleeve can easily cause the sealing ring to be pushed out; take a close look at the structure of the series dry gas seal
The secondary seal is generally an inert gas, nitrogen
1. If the primary seal gas is not in use, activating the secondary seal gas first will allow unfiltered gas from the compressor to enter the dry gas seal, thereby damaging it.
I’m not sure if what this sea friend said is correct I think I understand it the same way. Please ask an expert to help answer it