SEAL ASSEMBLY FOR CENTRIFUGAL COMPRESSORS

摘要

A sealing system for process gas leakage from a turbomachine casing is provided. The sealing system may include a seal assembly housing coupled to or integral with the turbomachine casing. The seal assembly housing defines a bore configured to receive a rotary shaft and a sealing assembly. The sealing assembly includes a plurality of carbon rings mounted circumferentially about the rotary shaft. The plurality of carbon rings may include an inboard carbon ring configured to prevent flow of a separation gas inboard of the barrier seal, an outboard carbon ring configured to prevent flow of contaminates into the seal assembly housing, and an intermediate carbon ring interposed between the inboard carbon ring and outboard carbon ring. A pressure differential is maintained across the inboard carbon ring, such that the separation gas is prevented from flowing inboard across the inboard carbon ring by a residual portion of a seal gas.

主权项

1. A sealing assembly configured to form a seal between a rotary shaft and a casing of a turbomachine having a high-pressure process gas, comprising:
a housing defining a bore configured to receive the rotary shaft and sealing assembly, wherein the housing is coupled to or integral with the casing and comprises an inboard end adjacent the casing and an outboard end distal the inboard end; at least one dry gas seal mounted circumferentially about the rotary shaft; a barrier seal mounted circumferentially about the rotary shaft and adjacent the outboard end of the housing, the barrier seal comprising:
an inboard carbon ring mounted circumferentially about the rotary shaft;an outboard carbon ring mounted circumferentially about the rotary shaft; andan intermediate carbon ring mounted circumferentially about the rotary shaft and interposed between the inboard carbon ring and the outboard carbon ring; at least one seal gas output conduit disposed inboard of the barrier seal and configured to remove at least a portion of an injected seal gas from the housing; and a separation gas output conduit disposed between the inboard carbon ring and the intermediate carbon ring and configured to remove at least a portion of an injected separation gas from the housing, wherein a seal gas pressure of the injected seal gas inboard of the inboard carbon ring is greater than the separation gas pressure of the injected separation gas between the inboard carbon ring and the intermediate carbon ring, such that the injected separation gas is prevented from flowing inboard across the inboard carbon ring and into the at least one seal gas output conduit.