Centrifugal compressor with rotating vaneless diffuser powered by leakage flow

Claim 2

A centrifugal compressor comprising a rotating impeller, a concentric rotating vaneless diffuser comprising substantially parallel front and back wall members wherein said back wall member extends radially inward and is mounted for rotation separated from said impeller by a clearance space, and means for coupling high pressure fluid flow exiting from said diffuser to an outlet, said impeller accelerating low pressure inlet fluid to a high velocity fluid with a substantial tangential velocity which is discharged into said diffuser to establish a vortex flow and partially escapes through said clearance space as leakage flow, and a leakage flow powering device carried by said back wall member which derives torque from said leakage flow for causing rotation of said rotating vaneless diffuser.

Claim 3

A centrifugal compressor according to claim 1 wherein said leakage flow powering device comprises an impulse turbine device secured to said back wall member in an appropriately shaped recess therein.

Claim 4

A centrifugal compressor according to claim 2 wherein said recess extends radially outwardly and inwardly of said impulse turbine device to respectively provide an entrance recess and an exit recess in which a radial leakage flow is established.

Claim 5

A centrifugal compressor according to claim 3 wherein said entrance recess has a limited arcuate extent to provide a partial arc of admission, and said impulse turbine device is comprised by a turbine blade row sector of correspondingly limited arcuate extent.

Claim 6

A centrifugal compressor according to claim 3 wherein said entrance recess is circumferentially continuous, and said impulse turbine device is comprised by a full turbine blade row.

Claim 7

A centrifugal compressor comprising a central rotating impeller, an annular rotating diffuser mounted for rotation concentric to said impeller and comprising substantially parallel front and back wall members defining a vaneless diffusion space which is separated radially from said impeller by an annular clearance space, and means for coupling high pressure fluid flow exiting from said diffuser to an outlet, said Impeller accelerating low pressure inlet fluid to a high velocity fluid with a substantial tangential velocity which is discharged into said rotating diffuser to establish a vortex flow and partially escapes through said clearance space as leakage flow, and leakage flow powered turbine means operatively coupled to said rotating diffuser to derive torque from said leakage flow for causing rotation of said rotating diffuser and for reducing said leakage flow.

Claim 8

A centrifugal compressor comprising a central rotating impeller, an annular rotating diffuser mounted for rotation concentric to said impeller and comprising substantially parallel front and back wall members defining a vaneless diffusion space which is separated radially from said impeller by an annular clearance space, and means for coupling high pressure fluid flow exiting from said diffuser to an outlet, said Impeller accelerating low pressure inlet fluid to a high velocity fluid with a substantial tangential velocity which is discharged into said rotating diffuser to establish a vortex flow and partially escapes through said clearance space as leakage flow, and leakage flow powered turbine means operatively coupled to said rotating diffuser to derive torque from said leakage flow for causing rotation of said rotating diffuser and for reducing said leakage flow.

Claim 9

A centrifugal compressor according to claim 6 wherein said leakage flow powered turbine means comprises a turbine blade row sector of limited arcuate extent and associated means defining a partial arc of admission of said leakage flow.

Claim 10

A centrifugal compressor according to claim 6 wherein said leakage flow powered turbine means comprises a circumferentially continuous turbine blade row and associated means defining complete admission of said leakage flow.

Claim 11

A centrifugal compressor according to claim 6 wherein one of said rotating diffuser wall members is extended radially inwardly with a relatively narrow clearance from said impeller, and said leakage flow powered turbine means comprises an impulse turbine blade row secured to said extended diffuser wall member in an appropriately shaped recess therein.