CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority under 35 U.S.C. § 119(e) to U.S. application Ser. No. 62/445,297, filed Jan. 12, 2017. This application is incorporated by reference herein in its entirety.
BACKGROUND OF THE INVENTION This application relates to various improvements in structures for fluid compressors.
Refrigerant compressors are utilized to compress a refrigerant for use in a refrigerant cycle.
In conventional rotary refrigerant compressors, energy may be wasted due to vibration and noise created by the compression cycle. These vibrations and noise are generated by the imbalance in the loads during the compression cycle, as the loading on the discharge pocket is different than the loading on the compression pocket, which are located on opposite sides of the rotating shaft from one another. Thus, the present inventors looked to find a way to eliminate this unbalanced loading in the compressor.
The present invention seeks to address these deficiencies.
SUMMARY OF THE INVENTION In one embodiment of the present invention, a fluid compressor includes a housing, a compression chamber, and a shaft including two vanes that each extend from the shaft to contact an inner surface of the compression chamber. The shaft, vanes, and inner surface of the compression chamber define at least two suction pockets and at least two discharge compression pockets arranged around a perimeter of the shaft. Each suction pocket is between two discharge pockets and each discharge pocket is between two suction pockets.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side cutaway view of a compressor in accordance with one embodiment of the present invention;
FIG. 2 is a top view of the shaft and vane assembly shown in FIG. 1;
FIG. 3 is a perspective view of a lower bearing and oil sump of one embodiment of the present invention;
FIG. 4 is a perspective view of the compression chamber without the shaft and vane assembly; and
FIG. 5 is a perspective view of a discharge valve assembly of one embodiment of the present invention;
FIG. 6 is a perspective view of the motor in the housing without the compression chamber assembly;
FIG. 7 is a perspective view of the upper bearing plate of one embodiment of the present invention;
FIG. 8 is a top view of the shaft 30 of one embodiment of the present invention;
FIG. 9 is a close up cross-sectional view of the connection between the stator laminates and the housing of one embodiment of the present invention;
FIG. 10 is a perspective view of a second embodiment of the upper bearing plate of one embodiment of the present invention; and
FIG. 11 is a cross-sectional side view of the connection between the intake port and the compression chamber in a “no” pressure embodiment of the present invention;
FIG. 12 is a cross-sectional side view of the connection between the discharge port and the compression chamber in a “no” pressure embodiment of the present invention;
FIG. 13 is a perspective view of a shaft according to alternative embodiment of the present invention;
FIG. 14 are views of a compression chamber according to alternative embodiment of the present invention;
FIG. 15 is a perspective view of a shaft detachable from a vane holding portion according to another alternative embodiment of the present invention; and
FIG. 16 is a perspective view of a vane holding portion of the shaft shown in FIG. 15.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows a fluid compressor 10 including a housing 25, a shaft 30, a motor 50, upper bearing 60, and lower bearing 70. Shaft 30 has apertures 32 (labeled in FIG. 8) into which vanes 35 can reciprocate back and forth as the shaft 30 turns. Motor 50 is mounted directly to housing 20, and drives shaft 30. Lower bearing 70 includes oil sump 72 which collects oil that lubricates the compressor parts as discussed herein. Thus, motor shaft 30 is supported symmetrically at both ends of shaft 30 for concentric motor rotor rotation for maximum efficiency and equal nominal air gap dimensional control.
FIG. 2 shows a top view of the compression chamber 20. Compression chamber 20, shaft 30, and vanes 35 cooperate to form two compression pockets 36 and two discharge pockets 37. The compression pockets 36 and discharge pockets 37 are on opposite sides of the shaft from one another, so that the loading on compressor 10 is balanced. Thus, compressor 10 generates dramatically less vibration and noise, and less bearing load, bearing friction, and wear. All motor torque and power is delivered to the circumferential compression movement. This directly leads to significant energy efficiency gains, and mechanism reliability, as the motor consumes more power if the compressor generates vibrations or noise. Further, the rotation of shaft 30 and balanced compression allows for rotation on the shaft centerline, as opposed to eccentric rotation in conventional rotary-type compressors. This “concentric compression” allows for balanced high speed rotation which then creates a very small displacement needed for a large output capacity. Accordingly, the present invention provides substantial energy and cost savings over conventional compressors and substantial capacity increases creating greater displacements in smaller material content.
In the embodiment shown in the figures, there are two compression pockets 36 and two discharge pockets 37. However, more than two compression pockets 36 and two discharge pockets 37 are possible in the present invention. For example, there could be four compression pockets 36 and four discharge pockets 37 arranged around a perimeter of the shaft, and this would also lead to balanced compression performance. All of these modifications are within the scope of the invention as claimed.
In this regard, FIG. 13 shows an exemplary shaft 30 including a vane holding portion 33 with eight vane holding slots 34. FIG. 14 shows a compression chamber 20 that is configured to be used with the eight vaned shaft of FIG. 13. Thus, the embodiment of FIGS. 13 and 14 would include 8 vanes separating the compression and discharge pockets, with a corresponding number of additional intake and exhaust valves being included in the design. Accordingly, compressors with more than two vanes (such as the illustrated eight vaned compressor of FIGS. 13 and 14) are within the scope of the invention as claimed.
In forming the compression pockets 36 and discharge pockets 37, shaft 30 comes in close proximity with the inside of the compression chamber 20. This is achieved by tight clearances on the two sides between shaft 30 and compression chamber 20 to prevent high pressure to low pressure leak paths. In other embodiments, compressor 10 can also have spring/pressure loaded/compliant vanes in the compression chamber 20 to press against shaft 30 for sealing and/or a compliant spring or pressure mechanism to provide a load for pressure sealing.
FIG. 3 shows another view of lower bearing 70. The slope of the oil sump 72 allows the use of less oil, 50% less in some configurations. This reduces both the initial and maintenance costs of the compressor, and forces the oil to drain to the oil pickup point in the shaft.
An additional feature of the present invention is that it can be configured as a high pressure machine (motor/oil area is exposed to high pressure fluid), a low pressure machine (motor/oil area is exposed to low pressure), or a “no” pressure machine (motor/oil area not exposed to fluid). In this regard, FIGS. 2, 4, and 5 show a low pressure machine configuration in which low pressure fluid enters the lower part of the compressor and high pressure fluid exits a top of the compressor. FIG. 4 shows intake aperture 22 in the floor of the compression chamber, through which low pressure gas enters the compression pockets 36. (A second intake aperture 22 is on an opposite side of the compression chamber and is not visible in FIG. 4.)
FIG. 5 shows high pressure exit valves 40 on a top of the compressor, as well as low pressure intake passage 42 and electrical feedthrough 48. Electrical feedthrough 48 is similar to that disclosed in U.S. Pat. No. 9,279,435, which is incorporated herein by reference in its entirety.
Further, “no” pressure machines may have two configurations. FIG. 11 shows a side cutaway view of a first embodiment of a “no” pressure machine in which the fluid comes in the bottom of compression chamber 20 and is discharged through the top of compression chamber 20. In this embodiment, fluid to be compressed enters the housing through low pressure intake passage 42. The fluid passes through passage 122 in flange 120 so that it does not enter the volume surrounding the motor/oil area, but travels directly to holes 62 in lower bearing flange 65 and passes through intake aperture 22. Thus, the fluid enters compression chamber 20 without ever being exposed to the motor/oil area. After compression, the fluid passes through discharge valves 40, as also shown in FIG. 5.
FIG. 12 shows a side cutaway view of a first embodiment of a “no” pressure machine in which the fluid comes in the top of compression chamber 20 and is discharged through the bottom of compression chamber 20. In this embodiment, fluid to be compressed enters the housing through intake aperture 22. After compression, the fluid passes through discharge valves 64 in lower bearing flange 65, and then through passage 122 in flange 120 so that it does not enter the volume surrounding the motor/oil area. The fluid then leaves the housing through discharge port 49.
In the “no” pressure configuration, the volume around the motor contains ambient air and, in contrast to the high and low pressure embodiments, does not contain oil. Thus, both “no” pressure configurations must have sufficient lubrication for the compressor parts without the oil used in the high and low pressure embodiments.
FIG. 6 shows the motor 50 within the housing 25. As noted above, motor 50 is directly mounted to and in contact with the inner surface of housing 25. Further, the outer surface of housing 25 may have heat dissipation fins and micro surface textures to enhance heat dissipation. For example, FIG. 9 shows a close up of the contact between the motor laminate layers 52 and the housing 25. (Although the housing has a circular cross-section, the housing is shown in this view as having straight sides due to the small scale.) Each stator laminate layer 52 has a thickness of approximately 0.020 inches. Each stator laminate layer 52 may then line up with a corresponding heat dissipation fin 26 on an outer surface of housing 25 to promote heat transfer from the laminate layer 52, through housing 25, and out corresponding fin 26. Fin 26 is shown with a triangular cross-section, but any shape or configuration suitable for heat dissipation is possible. These modifications are within the scope of the invention as claimed.
FIG. 7 shows the upper bearing flange 65 which includes upper bearing 60 and holes 62. In the low pressure machine shown in FIGS. 2, 4, and 5, holes 62 are in fluid communication with intake aperture 22 in the floor of the compression chamber. In contrast, in the high pressure machine configuration, holes 62 would be discharge holes with discharge valves 64 (shown in FIG. 10) mounted over the holes 62.
FIG. 8 shows a top view of shaft 30. Shaft 30 includes apertures 32 in which the vanes 35 reciprocate. Further, shaft 30 includes off center oil delivery passage 34. Oil delivery passage 34 uses centrifugal force to send oil out for increasing pressure and sending oil up to bearing 60. Vent holes in passage 34 supply lubrication to all moving surfaces.
FIGS. 15 and 16 show another alternative embodiment of the shaft 30. In this embodiment, the shaft 30 and the vane holding portion 33 are constructed as separate pieces that are then fit together during assembly, instead of the unitary machined shaft shown in FIG. 13 (for example). This allows for axial compliance and leeway during assembly and use. This allows for tight seals within the compression chamber while reducing wear due to manufacturing tolerances. Two piece shafts such as that shown in FIGS. 15 and 16 are also within the scope of the invention as claimed.
A worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.
