Compact centrifugal compressor

A compact centrifugal compressor having a center, comprising:

• a drive arrangement including a compressor input shaft;
• a hollow shaft;
• and
• an impeller driven by said compressor input shaft,
• wherein each of said compressor input shaft and said hollow shaft has an inner end adjacent to the center of the compressor and an outer end distal to the center of the compressor,
• wherein said compressor input shaft is connected to said hollow shaft at said inner ends,
• wherein the connection of said compressor input shaft to said hollow shaft is a keyless friction fit connection,
• wherein said compressor input shaft is flexible in at least a portion of the range of forces the compressor input shaft experiences during operation of the compressor, and
• wherein said compressor input shaft is devoid of indentations of a size on the order of size of a keyway,
• whereby the diameter of the compressor input shaft needed to drive the compressor is minimized.

A compact centrifugal compressor having a center, comprising:

• a drive arrangement including a compressor input shaft;
• a hollow shaft;
• an impeller driven by said compressor input shaft, wherein each of said compressor input shaft and said hollow shaft has an inner end adjacent to the center of the compressor and an outer end distal to the center of the compressor, and said compressor input shaft is connected to said hollow shaft at said inner ends;
• a casing enclosing the impeller and the inner ends of the compressor input shaft and the hollow shaft;
• and
• a seal within the casing, the seal extending from the casing to the hollow shaft and having a first part secured to the casing and a second part secured to the hollow shaft, the first and second parts being movable relative to one another and contacting one another to effect the seal,
• wherein said compressor input shaft is flexible in at least a portion of the range of forces the compressor input shaft experiences during operation of the compressor, and
• wherein said compressor input shaft is devoid of indentations of a size on the order of size of a keyway,
• whereby the diameter of the compressor input shaft needed to drive the compressor is minimized.

A compact centrifugal compressor having a center, comprising:

• a drive arrangement including a compressor input shaft;
• a hollow shaft;
• an impeller driven by said compressor input shaft, wherein each of said compressor input shaft and said hollow shaft has an inner end adjacent to the center of the compressor and an outer end distal to the center of the compressor, and said compressor input shaft is connected to said hollow shaft at said inner ends;
• a casing enclosing the impeller and the inner ends of the compressor input shaft and the hollow shaft;
• and
• a ball bearing secured to said casing and to said hollow shaft to support the hollow shaft for rotation relative to the casing, the ball bearing being a spring loaded angular contact bearing,
• wherein said compressor input shaft is flexible in at least a portion of the range of forces the compressor input shaft experiences during operation of the compressor, and
• wherein said compressor input shaft is devoid of indentations of a size on the order of size of a keyway,
• whereby the diameter of the compressor input shaft needed to drive the compressor is minimized.

A compact centrifugal compressor having a center, comprising:

• a drive arrangement including a compressor input shaft;
• a hollow shaft;
• an impeller driven by said compressor input shaft, wherein each of said compressor input shaft and said hollow shaft has an inner end adjacent to the center of the compressor and an outer end distal to the center of the compressor, and said compressor input shaft is connected to said hollow shaft at said inner ends;
• and
• a casing enclosing the impeller and the inner ends of the compressor input shaft and the hollow shaft,
• wherein the casing has a gear cavity containing gears for rotating the impeller and a compressor cavity containing the impeller,
• wherein there is only one opening between the gear cavity and the compressor cavity,
• wherein said only one opening is closed by an impeller drive shaft on which said impeller is mounted and by a seal surrounding said impeller drive shaft,
• wherein said compressor input shaft is flexible in at least a portion of the range of forces the compressor input shaft experiences during operation of the compressor, and
• wherein said compressor input shaft is devoid of indentations of a size on the order of size of a keyway,
• whereby the diameter of the compressor input shaft needed to drive the compressor is minimized.

A compact centrifugal compressor having a center, comprising:

• a drive arrangement including a compressor input shaft;
• a hollow shaft;
• an impeller driven by said compressor input shaft, wherein each of said compressor input shaft and said hollow shaft has an inner end adjacent to the center of the compressor and an outer end distal to the center of the compressor, and said compressor input shaft is connected to said hollow shaft at said inner ends.
• a casing enclosing the impeller and the inner ends of the compressor input shaft and the hollow shaft;
• and
• a central drive gear fixed on the inner end of the hollow shaft;
• and
• at least three gear shafts parallel to said hollow shaft, said gear shafts being mounted for rotation in the compressor around the circumference of the central hollow shaft gear, a first gear positioned on each of said gear shafts, each of said first gears engaging with and supporting said central drive gear,
• whereby the amount of torque that can be transmitted by a central drive gear to the impeller is greater than the torque that can be transmitted by such a central drive gear to the impeller via a single gear engaging the central drive gear,
• wherein said compressor input shaft is flexible in at least a portion of the range of forces the compressor input shaft experiences during operation of the compressor, and
• wherein said compressor input shaft is devoid of indentations of a size on the order of size of a keyway,
• whereby the diameter of the compressor input shaft needed to drive the compressor is minimized.

A compact centrifugal compressor having a center, comprising:

• a drive arrangement including a compressor input shaft;
• a hollow shaft;
• an impeller driven by said compressor input shaft, wherein each of said compressor input shaft and said hollow shaft has an inner end adjacent to the center of the compressor and an outer end distal to the center of the compressor, and said compressor input shaft is connected to said hollow shaft at said inner ends;
• a central drive gear fixed on the inner end of the hollow shaft;
• and
• at least three gear shafts parallel to said hollow shaft, said gear shafts being mounted for rotation in the compressor around the circumference of the central drive gear, a first gear positioned on each of said gear shafts, each of said first gears engaging with and supporting said central drive gear,
• whereby the amount of torque that can be transmitted by a central drive gear to the impeller is greater than the torque that can be transmitted by such a central drive gear to the impeller via a single gear engaging the central drive gear,
• a casing enclosing the impeller and the inner ends of the compressor input shaft and the hollow shaft;
• and
• wherein said compressor input shaft is flexible in at least a portion of the range of forces the compressor input shaft experiences during operation of the compressor, and
• wherein said compressor input shaft is devoid of indentations of a size on the order of size of a keyway,
• whereby the diameter of the compressor input shaft needed to drive the compressor is minimized.

A compact centrifugal compressor, comprising:

• a drive arrangement including a compressor input shaft;
• an impeller driven by said compressor input shaft;
• an impeller drive shaft axially aligned with said compressor input shaft, said impeller being mounted on said impeller drive shaft, wherein at least a portion of said impeller drive shaft is flexible in at least a portion of the range of forces the impeller drive shaft experiences during operation of the compressor,
• wherein said compressor input shaft is flexible in at least a portion of the range of forces the compressor input shaft experiences during operation of the compressor, and
• wherein said compressor input shaft is devoid of indentations of a size on the order of size of a keyway,
• whereby the diameter of the compressor input shaft needed to drive the compressor is minimized.