Seeking help with dry gas seal leakage issue
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Dear sea friends, why is the leakage amount of the compressor’s dry gas seal higher on the non-driving side than on the driving side in the first stage of the low-pressure cylinder, while in the first stage of the medium-pressure and high-pressure cylinders, the leakage amount is higher on the driving side than on the non-driving side?
The intermediate-pressure cylinder and the high-pressure cylinder: the drive end is larger than the non-drive end!
Are your data design data or operational data? Theoretically, during design the leakage amounts at the driving end and the non-driving end should be the same: 1. The pressure of the sealing gas supply for the first stage is identical in both cases ； 2. The pressure in the balance tubes of the same cylinder is the same ； 3. The backpressure of the torch is the same in the same cylinder. Therefore, the gas leakage rate of the primary seal is theoretically the same. The reasons for data inconsistency during actual operation may include deviations in the manufacturing of the dry gas seal, as well as variations in pipeline resistance during installation.
That’s right; the design parameters are the same, but in operation it happens as I mentioned. In particular, the leakage at the non-driving end of the low-pressure cylinder is much higher than that at the driving end – the leakage at the driving end is 11 standard liters, while it can reach 14 standard liters at the non-driving end. Moreover, the flow rate of air for the primary seal at the non-driving end is also significantly higher than that at the driving end
Check the shaft displacement deviations of each cylinder; it seems that large shaft displacement deviations may cause significant differences in the pre-tension of the dry gas seal springs at the driven and non-driven ends, thereby leading to flow rate variations.
“And the flow rate of the primary seal on the non-driving side is also much higher than that of the primary seal on the driving side. Are there any specific figures available?
Are you sure the gauge is that accurate? Which end is the high-voltage side?
1. Is it a problem with the instruments? Generally, there are pressure and flow displays on the vent line; if the flow rate is high, check whether the corresponding pressure is also high. 2. As someone mentioned above, could it be that the axial displacement differences for each shaft are different? 3. The design of the dry gas seal isn’t necessarily exactly the same in all cases. 4. The pre-tightening force of the static ring springs in the dry gas seal may vary. These are just my preliminary thoughts; I hope the experts can give me some guidance