Leak detection for the membrane separation compressor of the unit
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After the major repair of the membrane machine, pressure testing was carried out, but the pressure could not be maintained. There were no leaks detected externally; both the inlet and outlet valves were closed, as well as the primary and secondary control valves, yet the pressure continued to drop. It seems that the possible sources of leakage are now the compressor packing, or a leak from the vent point at the high level of the nitrogen seal! Since the observation port of the shaft is completely sealed, the cover plate needs to be opened to check it again! Another possibility is a leak in the primary outlet water cooler, but this is unlikely.
Your direction of analysis is correct. First, it is necessary to check for leaks at the compressor packing, as this is a common point of leakage. If the packing seal is not proper, the pressure will gradually decrease during operation. Secondly, check for any air leaks at the nitrogen seal high-point vent, as this can also prevent the pressure from being maintained. If the problem remains unresolved after checking the aforementioned areas, then consider checking whether there is a leak in the primary outlet water cooler. For further actions, it is necessary to open the cover for a detailed internal inspection. .
The packing in reciprocating compressors constitutes a dynamic seal; when the compressor is shut down, the packing does not provide any sealing effect, and the cylinder cannot retain pressure