Centrifugal compressor with improved range

Claim 2

In a compressor of the type having a centrifugal impeller and a diffuser at the periphery thereof, the diffuser including spaced sidewalls and spaced vanes extending therebetween, the spaces between the vanes having inlet ends adjacent the periphery of said impeller, the improvement comprising: means in connection with said diffuser forming a plenum; and passage-forming means establishing communication between the inlet ends of the spaces between the diffuser vanes and said plenum to equalize the pressure in the inlet ends of all such spaces during the operation of the compressor, said passage-forming means extending along a substantially constant static pressure line across each of said spaces and said plenum being otherwise closed to minimize fluid flow from said plenum through said passage-forming means.

Claim 3

The compressor improvement defined in claim 1 in which the plenum-forming means is disposed to provide a plenum at each side of the diffuser.

Claim 4

The compressor improvement defined in claim 2 in which the passage-forming means establishes communication between the plenums at each side of the diffuser and the spaces between the diffuser vanes.

Claim 5

The compressor improvement defined in claim 2 in which at least a portion of said diffuser vanes have passages therein establishing communication between the plenums at the sides of the diffuser.

Claim 6

The compressor improvement defined in claim 1 in which the passage-forming means include slots in a side wall of the diffuser.

Claim 7

The compressor improvement defined in claim 5 in which each slot is located in a plane disposed at an angle to the longitudinal axis of the space between diffuser vanes communicating with such slot.

Claim 8

The compressor improvement defined in claim 6 in which the angle at which the plane of the slot is disposed is substantially 90 degrees.

Claim 9

In a compressor of the type having a centrifugal impeller and a diffuser at the periphery thereof, the diffuser including spaced sidewalls and spaced vanes extending therebetween, the spaces between the vanes having inlet ends adjacent the periphery of said impeller, the improvement comprising: means in connection with said diffuser forming a plenum; and passage-forming means establishing communication between the inlet ends of the spaces between the diffuser vanes and said plenum to equalize the pressure in the inlet ends of all such spaces during the operation of the compressor, said passage-forming means extending along a substantially constant static pressure line across each of said spaces and said plenum being otherwise closed to minimize fluid flow from said plenum through said passage-forming means, said passage-forming means including slots in a side wall of the diffuser extending across the full width of the space between a pair of diffuser vanes.

Claim 10

In a compressor of the type having a centrifugal impeller and a diffuser at the periphery thereof, the diffuser including spaced sidewalls and spaced vanes extending therebetween, the spaces between the vanes having inlet ends adjacent the periphery of said impeller, the improvement comprising: means in connection with said diffuser forming a plenum; and passage-forming means establishing communication between the inlet ends of the spaces between the diffuser vanes and said plenum to equalize the pressure in the inlet ends of all such spaces during the operation of the compressor, said passage-forming means extending along a substantially constant static pressure line across each of said spaces and said plenum being otherwise closed to minimize fluid flow from said plenum through said passage-forming means, said passage-forming means including slots in a side wall of the diffuser extending across the full width of the space between a pair of diffuser vanes.

Claim 11

In a compressor of the type having a centrifugal impeller and a diffuser at the periphery thereof, the diffuser including spaced sidewalls and spaced vanes extending therebetween, the spaces between the vanes having inlet ends adjacent the periphery of said impeller, the improvement comprising: means in connection with said diffuser forming a plenum; and passage-forming means establishing communication between the inlet ends of the spaces between the diffuser vanes and said plenum to equalize the pressure in the inlet ends of all such spaces during the operation of the compressor, said passage-forming means extending along a substantially constant static pressure line across each of said spaces and said plenum being otherwise closed to minimize fluid flow from said plenum through said passage-forming means, said passage-forming means including slots in a side wall of the diffuser, each slot being located in a plane disposed at an angle of substantially 90 degrees to the longitudinal axis of the space between diffuser vanes communicating with such slot, each slot extending across the full width of the space between a pair of diffuser vanes.

Claim 12

In a compressor of the type having a centrifugal impeller and a diffuser at the periphery thereof, the diffuser including spaced sidewalls and spaced vanes extending therebetween, the spaces between the vanes having inlet ends adjacent the periphery of said impeller, the improvement comprising: means in connection with said diffuser forming a plenum; and passage-forming means establishing communication between the inlet ends of the spaces between the diffuser vanes and said plenum to equalize the pressure in the inlet ends of all such spaces during the operation of the compressor, said passage-forming means extending along a substantially constant static pressure line across each of said spaces and said plenum being otherwise closed to minimize fluid flow from said plenum through said passage-forming means, said passage-forming means including slots in a side wall of the diffuser, each slot being located in a plane disposed at an angle of substantially 90 degrees to the longitudinal axis of the space between diffuser vanes communicating with such slot, each slot extending across the full width of the space between a pair of diffuser vanes.

Claim 13

The compressor improvement defined in claim 9, wherein said diffuser vanes have inner ends at a preselected radial distance from the compressor rotational axis, said slots being arranged in planes intersecting said longitudinal axis of the associated space at said preselected radial distance from said rotational axis.

Claim 14

In a compressor of the type having a centrifugal impeller and a diffuser at the periphery thereof, the impeller having hub and shroud sides, the diffuser including spaced sidewalls registering substantially with the hub and shroud sides of the impeller and spaced vanes extending between the sidewalls, the vanes having leading edges disposed a predetermined distance from the axis of rotation of the impeller and defining the inlet ends of the diffuser passages formed by the vanes, the improvement comprising: means on the diffuser forming a chamber adjacent a side wall thereof, the chamber being substantially coextensive with the diffuser; and passage-forming means in the diffuser wall adjacent the chamber establishing communication between the chamber and each diffuser passage at the inlet end thereof, said passage-forming means comprising a thin slot at said inlet end of each diffuser passage extending along a substantially constant static pressure line across the associated diffuser passage, said chamber being otherwise substantially closed to minimize fluid flow from said chamber through said passage-forming means while substantially equalizing pressure at said inlet ends of said diffuser passages to counteract any tendency of formation of localized stall conditions at any one of said diffuser passages prior to occurrence of general stall conditions simultaneously in substantially all of said diffuser passages.

Claim 15

In a compressor of the type having a centrifugal impeller and a diffuser at the periphery thereof, the impeller having hub and shroud sides, the diffuser including spaced sidewalls registering substantially with the hub and shroud sides of the impeller and spaced vanes extending between the sidewalls, the vanes having leading edges disposed a predetermined distance from the axis of rotation of the impeller and defining the inlet ends of the diffuser passages formed by the vanes, the improvement comprising: means on the diffuser forming a chamber adjacent a side wall thereof, the chamber being substantially coextensive with the diffuser; and passage-forming means in the diffuser wall adjacent the chamber establishing communication between the chamber and each diffuser passage at the inlet end thereof, said passage-forming means comprising a thin slot at said inlet end of each diffuser passage extending along a substantially constant static pressure line across the associated diffuser passage, said chamber being otherwise substantially closed to minimize fluid flow from said chamber through said passage-forming means while substantially equalizing pressure at said inlet ends of said diffuser passages to counteract any tendency of formation of localized stall conditions at any one of said diffuser passages prior to occurrence of general stall conditions simultaneously in substantially all of said diffuser passages.

Claim 16

The compressor improvement defined in claim 11 in which the means on the diffuser forms a chamber adjacent each side wall thereof, both chambers being substantially coextensive with the diffuser and passage-forming means are provided in each diffuser wall to establish communication between the chamber adjacent thereto and each diffuser passage at the inlet end thereof.

Claim 17

The compressor improvement defined in claim 12 in which the passage-forming means consists of narrow slots each disposed in a plane at right angles to the longitudinal axis of the diffuser passage communicating therewith, the intersections of the planes of the slots and the longitudinal axes of the diffuser passages being the same distance from the axis of rotation of the impeller as the leading edges of the diffuser vanes.