Compressor throttling valve assembly
View Patent ↗A throttling valve assembly has an outer housing that is sealed. An actuator is connected to a pressure balanced shaft that extends into the housing to operate a plurality of linkages that can rotate blades in tandem. With the surrounding housing sealed, the shaft penetrations of the blade support shafts no longer need seals or a purge system to supply process gas during times of reduced pressure in situations with the blades nearly closed. A pressure equalization system has balance passages internal to the housing to allow flow from higher pressure zones to lower pressure zone of the process gas so as to avoid creation of a condition that can draw air into any zones of reduced pressure in the housing.
1. A control device for a compressor, comprising:
an inner housing connected for flow communication to the compressor, the inner housing comprising a valve member having at least one operating shaft extending through the inner housing, wherein the operating shaft is not sealed as it extends through the inner housing; and
an outer housing sealingly surrounding the inner housing.
2. The control device of claim 1 , comprising:
a higher pressure zone and a lower pressure zone; and
a pressure equalizing device between the higher and lower pressure zones.
3. The control device of claim 1 , further comprising:
an operating rod extending into the outer housing in a pressure balanced configuration for operating the operating shaft of the valve member.
4. The control device of claim 2 , wherein:
the pressure equalizing device comprises a passage linking the higher pressure zone within the inner housing to an annular space between the inner and outer housings.
5. The control device of claim 1 , wherein:
the inner housing is formed to also serve as a closure for the outer housing while defining an annular space therebetween.
6. The control device of claim 3 , wherein:
the operating rod makes two opposed penetrations of the outer housing, the penetrations sealed by redundant seals.
7. The control device of claim 3 , wherein:
portions of the operating rod exposed within the outer housing present a symmetrical configuration to obtain the pressure balance aspect of the operating rod.
8. The control device of claim 4 , wherein:
the passage extends in a wall of the outer housing.
9. The control device of claim 4 , wherein:
the passage extends to an exterior of the outer housing to allow connection to a source of purge gas to the annular space.
10. A control device for a compressor, comprising:
an inner housing connected for flow communication to the compressor, the inner housing comprising a valve member having at least one operating shaft extending therethrough; and
an outer housing sealingly surrounding the inner housing;
wherein the inner housing is formed to also serve as a closure for the outer housing while defining an annular space therebetween.
11. The control device of claim 10 , wherein:
a higher pressure zone and a lower pressure zone; and
a pressure equalizing device between the higher and lower pressure zones.
12. The control device of claim 11 , wherein:
the pressure equalizing device comprises a passage linking the higher pressure zone within the inner housing to the annular space.
13. The control device of claim 12 , wherein:
the passage extends in a wall of the outer housing.
14. The control device of claim 12 , wherein:
the passage extends to an exterior of the outer housing to enable connection to a source of purge gas to the annular space.
15. The control device of claim 10 , further comprising:
an operating rod extending into the outer housing in a pressure balanced configuration for operating the operating shaft of the valve member.
16. The control device of claim 15 , wherein:
the operating rod makes two opposed penetrations of the outer housing, the penetrations sealed by redundant seals.
17. The control device of claim 15 , wherein:
portions of the operating rod exposed within the outer housing present a symmetrical configuration to obtain the pressure balance aspect of the operating rod.
18. The control device of claim 10 , wherein the operating shaft is not sealed as it extends through the inner housing.
19. A control device for a compressor, comprising:
an outer housing;
an inner housing sealingly surrounded by the outer housing and connected for flow communication to the compressor;
a valve member having at least one operating shaft extending through the inner housing, wherein the operating shaft is not sealed as it extends through the inner housing;
a higher pressure zone and a lower pressure zone;
a pressure equalizing device between the higher and lower pressure zones; and
an operating rod extending into the outer housing in a pressure balanced configuration for operating the operating shaft of the valve member.
20. The control device of claim 19 , wherein:
the pressure equalizing device comprises a passage linking the higher pressure zone within the inner housing to an annular space between the inner and outer housings.
21. The control device of claim 20 , wherein:
the passage extends to an exterior of the outer housing to allow connection to a source of purge gas to the annular space.
22. The control device of claim 19 , wherein:
the operating rod makes two opposed penetrations of the outer housing, the penetrations sealed by redundant seals.