US-12624696-B2 - Scavenge loss limiter for a rotary compressor

Abstract

A fluid compressor system has a scavenge loss limiter that increases the efficiency of the fluid compressor system by reducing the compressed working fluid recirculated into the airend through a scavenge flow. The scavenge loss limiter includes a scavenge hole positioned at a discharge end face of a rotor cavity of the compressor housing. As a rotor of the compressor system rotates, the rotor may intermittently restrict the free-flowing scavenge flow returning from a lubricant separation tank. The rotor may be a male rotor having a plurality of male lobes. As the discharge end clearance between the rotor and the discharge end face is tightly controlled and monitored, a better control of the scavenge flow returning to the rotor cavity is achieved.

Inventors

• Taylor Stratman

Assignees

• INGERSOLL-RAND INDUSTRIAL U.S., INC.

Dates

Publication Date

20260512

Application Date

20250107

Claims (20)

1. 1 . A rotary compressor comprising: a housing having a rotor cavity and an interior wall; a rotor housed within the rotor cavity and rotating about a rotor axis, the rotor having a plurality of lobes; and a scavenge loss limiter disposed within the interior wall, the scavenge loss limiter comprising a scavenge passage and a scavenge orifice; wherein the scavenge loss limiter is configured to recirculate scavenge flow from an oil separator into the rotor cavity as the rotation of the rotor intermittently covers and uncovers the scavenge orifice.
2. 2 . The rotary compressor of claim 1 , wherein the rotor comprises a rotor root radius and a lobe maximum radius from the rotor axis, and wherein the scavenge orifice is disposed at an orifice radius from the rotor axis, where the orifice radius is greater than the rotor root radius and less than the lobe maximum radius.
3. 3 . The rotary compressor of claim 1 , wherein the housing comprises a bearing assembly, and wherein the scavenge passage is configured to direct a scavenge flow through the bearing assembly prior to recirculating the scavenge flow into the rotor cavity.
4. 4 . The rotary compressor of claim 3 , wherein the rotor includes a scavenge groove configured to receive the scavenge flow from the scavenge passage.
5. 5 . The rotary compressor of claim 4 , wherein the scavenge groove is disposed in a rotor shaft of the rotor.
6. 6 . The rotary compressor of claim 4 , wherein the bearing assembly comprises a bearing cavity, and wherein the scavenge groove directs the scavenge flow to the bearing cavity, the bearing cavity configured to be lubricated by the scavenge flow.
7. 7 . The rotary compressor of claim 4 , wherein the rotor comprises a rotor end face, and wherein the scavenge groove is disposed on the rotor end face.
8. 8 . The rotary compressor of claim 7 , wherein the scavenge groove is open to the rotor cavity.
9. 9 . A rotary compressor comprising: a housing having a rotor cavity and an interior wall; a rotor housed within the rotor cavity, rotating about a rotor axis; and a scavenge loss limiter disposed within the interior wall, the scavenge loss limiter including a scavenge passage and a scavenge orifice, the scavenge orifice connecting the scavenge passage with the rotor cavity; wherein the scavenge loss limiter is configured to recirculate scavenge flow from an oil separator into the rotary rotor cavity as the rotation of the rotor intermittently opens and closes the scavenge orifice.
10. 10 . The rotary compressor of claim 9 , further comprising a second rotor housed within the rotor cavity.
11. 11 . The rotary compressor of claim 9 , wherein the scavenge orifice is disposed at an orifice radius from the rotor axis, where the orifice radius is greater than a rotor root radius and less than a rotor lobe maximum radius.
12. 12 . The rotary compressor of claim 9 , wherein the scavenge passage is configured to direct a scavenge flow through a bearing assembly prior to recirculating the scavenge flow into the rotor cavity.
13. 13 . The rotary compressor of claim 12 , wherein the rotor includes a scavenge groove configured to receive the scavenge flow from the scavenge orifice.
14. 14 . The rotary compressor of claim 13 , wherein the scavenge groove is disposed in a rotor shaft of the rotor.
15. 15 . The rotary compressor of claim 13 , wherein the scavenge groove directs the scavenge flow to a bearing cavity, the bearing cavity configured to be lubricated by the scavenge flow.
16. 16 . The rotary compressor of claim 13 , wherein the scavenge groove is disposed on a rotor end face.
17. 17 . The rotary compressor of claim 16 , wherein the scavenge groove is open to the rotor cavity.
18. 18 . A compressor system comprising: an airend configured to compress a working fluid, the airend including: a housing having a rotor cavity and an interior wall; a rotor housed within the rotor cavity, rotating about a rotor axis; and a scavenge loss limiter disposed within the first interior wall, the scavenge loss limiter including a scavenge passage and a scavenge orifice, the scavenge orifice connecting the scavenge passage with the rotor cavity; and a lubricant separator configured to separate a lubricant from the working fluid, the lubricant separator delivering a scavenge flow to the airend; wherein the scavenge loss limiter is configured to recirculate the scavenge flow into the rotary rotor cavity as the rotation of the rotor intermittently opens and closes the scavenge orifice.
19. 19 . The compressor system of claim 18 , wherein the scavenge orifice is disposed at an orifice radius from the rotor axis, where the orifice radius is greater than a rotor root radius and less than a rotor maximum lobe radius.
20. 20 . The compressor system of claim 18 , wherein the scavenge passage is configured to direct a scavenge flow through a bearing assembly prior to recirculating the scavenge flow into the rotor cavity.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present application is a continuation of U.S. patent application Ser. No. 18/581,865, filed Feb. 20, 2024, and titled “SCAVENGE LOSS LIMITER FOR A ROTARY COMPRESSOR”. U.S. patent application Ser. No. 18/581,865 is herein incorporated by reference in its entirety. BACKGROUND Fluid compressor systems are widely used in a variety of industries such as in construction, manufacturing, agriculture, energy production, etc. As fluid compressors compress a working fluid, heat is produced as a result of the pressure increase in the working fluid. To reduce the heat produced by the compression process and lubricate mechanical components, compressor systems may inject a lubricant (e.g., oil, etc.) into the compressor airend. These compressors are known as contact-cooled compressors. DRAWINGS The Detailed Description is described with reference to the accompanying figures. The use of the same reference numbers in different instances in the description and the figures may indicate similar or identical items. FIG. 1 is an isometric view illustrating a rotary compressor with a scavenge loss limiter in accordance with example embodiments of the present disclosure. FIG. 2 is a cross-sectional side view of a rotary compressor, as shown in FIG. 1 along line 2-2, the rotary compressor having a male root scavenge limiter in accordance with example embodiments of the present disclosure. FIG. 3 is a cross-sectional front view of the rotary compressor shown in FIG. 2 along line 3-3, having a scavenge limiter orifice in accordance with example embodiments of the present disclosure. FIG. 4 is a cross-sectional isometric view of a rotary compressor, as shown in FIG. 1, the rotary compressor having a shaft scavenge limiter in accordance with example embodiments of the present disclosure. FIG. 5 is a cross-sectional top view of the rotary compressor as shown in FIG. 4, the rotary compressor having a shaft scavenge limiter in accordance with example embodiments of the present disclosure. FIG. 6 is an isometric view of a rotor shaft, as shown in FIG. 4, the rotor shaft having a shaft scavenge groove in accordance with example embodiments of the present disclosure. FIG. 7 is a cross-sectional front view of the rotary compressor shown in FIG. 5 along line 7-7, showing a bearing return passage connecting a bearing assembly with a rotor cavity in accordance with example embodiments of the present disclosure. FIG. 8 is a cross-sectional side view of a rotary compressor, as shown in FIG. 1, the rotary compressor having a rotor orifice scavenge limiter in accordance with example embodiments of the present disclosure. FIG. 9 is an isometric view of the rotor shown in FIG. 8, the rotor having a rotor scavenge orifice in accordance with example embodiments of the present disclosure. FIG. 10 is a cross-sectional isometric view of a rotary compressor, as shown in FIG. 1, a rotor of the rotary compressor having a blind-orifice scavenge limiter in accordance with example embodiments of the present disclosure. FIG. 11 is a cross-sectional side view of the rotary compressor of FIG. 10, along line 11-11, the rotary compressor having a bearing return passage connecting a bearing assembly with a rotor cavity in accordance with example embodiments of the present disclosure. FIG. 12 is a partial cross-sectional top view of the rotary compressor of FIG. 11 along line 12-12, showing a rotor blind-orifice and a bearing lubrication passage in accordance with example embodiments of the present disclosure. FIG. 13 is a schematic view of a compressor system including a contact-cooled rotary compressor and a separator tank in accordance with example embodiments of the present disclosure. DETAILED DESCRIPTION For the purposes of promoting an understanding of the principles of the subject matter, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the subject matter is thereby intended. Any alterations and further modifications in the described embodiments, and any further applications of the principles of the subject matter as described herein are contemplated as would normally occur to one skilled in the art to which the subject matter relates. Overview Contact-cooled compressors, such as rotary screw compressors, separate the working fluid (e.g., air, gas, etc.) from the lubricant and other undesired particles in a separator process. The separation process starts in an oil sump in a separator tank, where a majority of the lubricant (around 95%) is separated from the compressed working fluid. The compressed working fluid is then directed to a coalescing-type filter. The coalescing-type filter intercepts and coalesces the remaining aerosol lubricant stream in the compressed working fluid as it exits the initial inertial separation process within the oil sump. The coalescing-type