Page 540 - Subyek Teknik Mesin - Forsthoffers Best Practice Handbook for Rotating Machinery by William E Forsthoffer

Dry Gas Seal Best Practices Be st Practice 9.1

Fig 9.1.14 Typical tandem seal system for dry process gas

Fig 9.1.15 Tandem seal with interstage labyrinth (Courtesy of Flowserve Corp.)

Double seal system for dry gas or used, afteritisconditioned,or an externalsourceif itiscompatible
saturated gas application with the process gas. If the gas used between the seals is toxic or
flammable, a suitable barrier seal, provided with nitrogen, as
Figure 9.1.17 depicts a double seal, used in either dry gas or sat- shown in Figure 9.1.12, must be used. The seal systems previously
urated gas applications where the process gas is not permitted to shown will be used for the supply of conditioned gas to the seals as
exit the compressor case. For this application process gas can be required by the condition of the seal gas (dry or saturated).

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