Page 544 - Subyek Teknik Mesin - Forsthoffers Best Practice Handbook for Rotating Machinery by William E Forsthoffer

Dry Gas Seal Best Practices Be st Practice 9.3

Fig 9.3.1 Double dry gas seal

Fig 9.3.2 Tandem dry gas seal

failure. If process gas can blow through the separation seal and
into the bearing housing, a catastrophic equipment failure could
occur. Therefore, the best practice is to monitor the condition of - Low pressure differential between the separation seal inlet
the secondary or outer seal by measuring one of the following and secondary vent pressure (if the separation gas is
(Figures 9.3.1, 9.3.2): controlled at a fixed pressure).
- Low pressure in the primary seal vent e this assumes that
- High pressure in the secondary vent e suggested setting: 1e2 a pressure of 30e40 kPag (5 psig) is normally maintained
kPag (5e10 inches water column). between the primary and secondary seals.

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