Patent Application
20080152526
The present disclosure relates to scroll compressors and more specifically to vapor injection systems for scroll compressors.
Refrigerant compressors for cooling systems such as air conditioning, refrigeration or chiller systems, may include a vapor injection system to increase operating efficiency and capacity. During operation, passages between the vapor injection system and the compression mechanism may create dead volume that is compressed, consuming energy unnecessarily.
A compressor may include a shell, a compression mechanism, a motor, and a vapor injection system. The compression mechanism may be contained within the shell and include a non-orbiting scroll axially displaceably mounted to the shell. The non-orbiting scroll may have an exterior portion, an interior portion, and a vapor injection passage extending therethrough from the exterior portion to the interior portion. The motor may be contained within the shell and may be drivingly coupled to the compression mechanism. The vapor injection system may include a vapor injection device, a vapor injection fitting, and a vapor injection valve. The vapor injection fitting may be in communication with the vapor injection device and the vapor injection passage. The vapor injection valve may be disposed between the shell and the interior of the non-orbiting scroll.
Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the claims.
The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.
The following description is merely exemplary in nature and is not intended to limit the present teachings, application, or uses.
The present teachings are suitable for incorporation in many different types of scroll and rotary compressors, including hermetic machines, open drive machines and non-hermetic machines. For exemplary purposes, a hermetic scroll refrigerant motor-compressor 10 of the low-side type, i.e., where the motor and compressor are cooled by suction gas in the hermetic shell, as illustrated in the vertical section shown in
With reference to
The motor assembly 18 may generally include a motor 32, a frame 34 and a crankshaft 36. The motor 32 may include a motor stator 38 and a rotor 40. The motor stator 38 may be press fit into a frame 34, which may in turn be press fit into shell 12. Crankshaft 36 may be rotatably driven stator 38. Windings 42 may pass through stator 38. Rotor 40 may be press fit on crankshaft 36. A motor protector 44 may be provided in close proximity to windings 42 so that motor protector 44 will de-energize the motor 32 if the windings 42 exceed their normal temperature range.
The crankshaft 36 may include an eccentric crank pin 46 and one or more counter-weights 48 at an upper end 50. Crankshaft 36 may be rotatably journaled in a first bearing 52 in main bearing housing 16 and in a second bearing 54 in frame 34. Crankshaft 36 may include an oil-pumping concentric bore 56 at a lower end 58. Concentric bore 56 may communicate with a radially outwardly inclined and relatively smaller diameter bore 60 extending to the upper end 50 of crankshaft 36. The lower portion of interior shell 12 may be filled with lubricating oil. Concentric bore 56 may provide pump action in conjunction with bore 60 to distribute lubricating fluid to various portions of compressor 10.
Compression mechanism 14 may generally include an orbiting scroll 62 and a non-orbiting scroll 64. Orbiting scroll 62 may include an end plate 66 having a spiral vane or wrap 68 on the upper surface thereof and an annular flat thrust surface 70 on the lower surface. Thrust surface 70 may interface with an annular flat thrust bearing surface 72 on an upper surface of main bearing housing 16. A cylindrical hub 74 may project downwardly from thrust surface 70 and may include a journal bearing 76 having a drive bushing 78 rotatively disposed therein. Drive bushing 78 may include an inner bore in which crank pin 46 is drivingly disposed. Crank pin 46 may have a flat on one surface (not shown) that drivingly engages a flat surface in a portion of the inner bore of drive bushing 78 to provide a radially compliant driving arrangement, such as shown in assignee's U.S. Pat. No. 4,877,382, the disclosure of which is herein incorporated by reference.
Non-orbiting scroll 64 may include an end plate 80 having a non-orbiting spiral wrap 82 on the lower surface 84 thereof. Non-orbiting spiral wrap 82 may form a meshing engagement with wrap 68 of orbiting scroll 62, thereby creating an inlet pocket 86, intermediate pockets 88, 90, 92, 94, and outlet pocket 96. Non-orbiting scroll 64 may have a centrally disposed discharge passageway 98 in communication with outlet pocket 96 and upwardly open recess 100 which may be in fluid communication with discharge fitting 20.
Non-orbiting scroll member 64 may include an annular recess 101 in the upper surface thereof having parallel coaxial side walls in which an annular floating seal 102 is sealingly disposed for relative axial movement. The bottom of recess 101 may be isolated from the presence of gas under suction and discharge pressure by floating seal 102 so that it can be placed in fluid communication with a source of intermediate fluid pressure by means of a passageway (not shown). The passageway may extend into an intermediate pocket 88, 90, 92, 94. Non-orbiting scroll member 64 may therefore be axially biased against orbiting scroll member 62 by the forces created by discharge pressure acting on the central portion of scroll member 64 and those created by intermediate fluid pressure acting on the bottom of recess 101.
With additional reference to
Non-orbiting scroll 64 may be mounted to main bearing housing 16 in any manner that will provide limited axial movement of non-orbiting scroll member 64. For a more detailed description of the non-orbiting scroll suspension system, see assignee's U.S. Pat. No. 5,055,010, the disclosure of which is hereby incorporated herein by reference.
Relative rotation of the scroll members 62, 64 may be prevented by an Oldham coupling, which may generally include a ring 103 having a first pair of keys 105 (one of which is shown) slidably disposed in diametrically opposed slots 107 (one of which is shown) in non-orbiting scroll 64 and a second pair of keys (not shown) slidably disposed in diametrically opposed slots in orbiting scroll 62.
The vapor injection system 24 may include a vapor injection device 114, a top cap fitting 116, a scroll fitting 118, and a top cap seal 120. Vapor injection device 114 may be located external to shell 12 and may be in communication with scroll fitting 118 through top cap fitting 116. Top cap fitting 116 may be in the form of a flexible line and may pass through and be fixed to opening 126 in shell 12.
Scroll fitting 118 may be in the form of a block fixed to sidewall 110 of non-orbiting scroll 64. Scroll fitting 118 may include an upper recessed portion 128 having top cap seal 120 disposed therein and engaged with end cap 26. Top cap seal 120 may provide sealed communication between top cap fitting 116 and scroll fitting 118, while allowing axial displacement of scroll fitting 118 relative to shell 12. Top cap seal 120 may be any of the seals noted above regarding seal 102.
Scroll fitting 118 may include first and second passages 130, 132 therethrough. First passage 130 may extend generally longitudinally from upper recessed portion 128. Second passage 132 may intersect first passage 130 and extend generally radially through scroll fitting 118. Scroll fitting 118 may include a side recessed portion 134 near second passage 132. Side recessed portion 134 may have a diameter greater than the diameter of second passage 132 and generally surround vapor injection passage opening 112. An annular wall 133 may extend into side recessed portion 134, forming an annular recess 135 therebetween. First and second passages 130, 132 may therefore be in communication with vapor injection passage 104a, generally forming a vapor injection passageway therewith.
With reference to
With reference to
Alternately, as seen in
Operation of valve 122 will now be discussed with the understanding that the description applies equally to valve 124. As indicated above, valve member 136 is urged to a closed position by the combination of spring 138 and flow from intermediate pocket 92. The flow from intermediate pocket 92 and spring 138 produce a force on a back side of valve member 136, and therefore bias valve member 136 in a direction of flow from an interior portion to an exterior portion of non-orbiting scroll member 64.
During compressor operation, the pressure of the fluid within intermediate pocket 92 varies with rotation of crankshaft 36. More specifically, during each rotation of crankshaft 36, the fluid pressurized within intermediate pocket 92 may vary over a range of pressures. For exemplary purposes, fluid pressure in intermediate pocket 92 may vary between a first pressure and a second pressure and vapor injection device 114 may provide a fluid at an intermediate pressure between the first and second pressures. When the fluid provided by vapor injection device 114 provides a force on a front side of valve member 136, valve 122 will move between opened and closed positions based on the difference between the force provided by the intermediate fluid pressure from vapor injection device 114 on the front side of valve member 136 and the combination of the biasing force of spring 138 and the variable force provided by fluid from intermediate pocket 92 on the back side of valve member 136. The difference in force provided by the first and second fluid pressures from intermediate pocket 92 during each rotation of crankshaft 36 allows valve 122 to open and close once per revolution of crankshaft 36.
