Patent Application
20070059193
The present invention relates to scroll type machines. More particularly, the present invention relates to scroll compressors incorporating a vapor injection system which utilizes a crimped tube design for the piping of the fluid injection system.
Refrigeration and air conditioning systems generally include a compressor, a condenser, an expansion valve or equivalent, and an evaporator. These components are coupled in sequence in a continuous flow path. A working fluid flows through the system and alternates between a liquid phase and a vapor or gaseous phase.
A variety of compressor types have been used in refrigeration systems, including but not limited to reciprocating compressors, screw compressors and rotary compressors. Rotary compressors can both include the vane type compressors, the scroll machines as well as other rotary machines. Scroll machines are constructed using two scroll members with each scroll member having an end plate and a spiral wrap. The spiral wraps are arranged in an opposing manner with the two spiral wraps being interfitted. The scroll members are mounted so that they may engage in relative orbiting motion with respect to each other. During this orbiting movement, the spiral wraps define a successive series of enclosed spaces, each of which progressively decreases in size as it moves inwardly from a radially outer position at a relatively low suction pressure to a central position at a relatively high pressure. The compressed gas exits from the enclosed space at the central position through a discharge passage formed through the end plate of one of the scroll members.
Refrigeration systems are now incorporating fluid injection systems where a portion of the refrigerant is injected into the enclosed spaces at a pressure which is intermediate the low suction pressure and the relatively high pressure or what is termed discharge pressure. This refrigerant is injected into the enclosed spaces through injection ports extending through one of the two scroll members. The injection of this refrigerant has the effect of cooling the compressor and/or increasing both system capacity and the efficiency of the compressor. The source for supplying the intermediate pressurized refrigerant is typically provided from a different portion of the refrigeration system which is located outside of the hermetic shell of the compressor. Typically a flash tank, an economizer, an accumulator or a different component in the refrigerant cycle is the source for the intermediate pressurized refrigerant.
When developing the fluid injection system, the development engineer must ensure that the intermediate pressurized refrigerant that is being injected is routed from the component outside the hermetic shell, through the hermetic shell and to the fluid injection ports. Piping or tubing extends between the component supplying the intermediate pressurized refrigerant to a pipe or tube fitting that is sealingly secured to and that extends through the hermetic shell of the compressor assembly and then to an internal pipe or tube which extends between the pipe or tube fitting and the injection port on one of the components of the compressor. When the pipe or tube is assembled or connected between the injection port and the pipe or tube fitting on the hermetic shell, the connection must be a sealed connection to avoid the leaking of the refrigerant to the internal space of the hermetic shell and to the environment.
Thus, the continued development of fluid injection systems is directed towards providing more efficient and lower cost connection designs for use between the pipe or tubing and the pipe or tubing fitting.
The present invention provides the art with a fluid injection system which utilizes a crimped fitting for the attachment of the pipe or tube to the pipe or tube fitting. The refrigerant tube is assembled to the fitting and then a tool engages the fitting and/or the tube to create a sealed connection without having to solder or braze the connection.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.
The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:
The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.
Referring now to the drawings in which like reference numerals designate like or corresponding parts throughout the several views, there is shown in
Scroll compressor 10 comprises a generally cylindrical hermetic shell 12 having welded at the upper end thereof a cap 14 and at the lower end thereof a base 16 having a plurality of mounting feet (not shown) integrally formed therewith. Cap 14 is provided with a refrigerant discharge fitting 18 which may have the usual discharge valve therein (not shown). Other major elements affixed to shell 12 include a transversely extending partition 20 which is welded about its periphery at the same point cap 14 is welded to shell 12, an inlet fitting 22, a main bearing housing 24 which is suitably secured to shell 12 and a lower bearing housing 26 having a plurality of radially outwardly extending legs each of which is suitably secured to shell 12. A motor stator 28 which is generally square in cross-section but with the corners rounded off is press fit into shell 12. The flats between the rounded corners on motor stator 28 provide passageways between motor stator 28 and shell 12 which facilitate the return flow of the lubricant from the top of shell 12 to its bottom.
A drive shaft or crankshaft 30 having an eccentric crank pin 32 at the upper end thereof is rotatably journaled in a bearing 34 in main bearing housing 24 and in a bearing 36 in lower bearing housing 26. Crankshaft 30 has at the lower end thereof a relatively large diameter concentric bore 38 which communicates with a radially outwardly located smaller diameter bore 40 extending upwardly therefrom to the top of crankshaft 30. Disposed within bore 38 is a stirrer 42. The lower portion of the interior shell 12 is filled with lubricating oil and bores 38 and 40 act as a pump to pump the lubricating oil up crankshaft 30 and ultimately to all of the various portions of compressor 10 which require lubrication.
Crankshaft 30 is rotatably driven by an electric motor which includes motor stator 28 having motor windings 44 passing therethrough and a motor rotor 46 press fitted onto crankshaft 30 and having upper and lower counterweights 48 and 50, respectively. A motor protector 52, of the usual type, is provided in close proximity to motor windings 44 so that if the motor exceeds its normal temperature range, motor protector 52 will de-energize the motor.
The upper surface of main bearing housing 24 is provided with an annular flat thrust bearing surfaces 54 on which is disposed an orbiting scroll member 56. Orbiting scroll member 56 comprises an end plate 58 having the usual spiral valve or wrap 60 on the upper surface thereof and an annular flat thrust surface 62 on the lower surface thereof. Projecting downwardly from the lower surface is a cylindrical hub 64 having a journal bearing 66 therein and in which is rotatively disposed a drive bushing 68 having an inner bore within which crank pin 32 is drivingly disposed. Crank pin 32 has a flat on one surface (not shown) which drivingly engages a flat surface in a portion of the inner bore of drive bushing 68 to provide a radially compliant drive arrangement such as shown in assignee's U.S. Pat. No. 4,877,382, the disclosure of which is incorporated herein by reference.
Wrap 60 meshes with a non-orbiting scroll wrap 72 forming part of a non-orbiting scroll member 74. During orbital movement of orbiting scroll member 56 with respect to non-orbiting scroll member 74 creates moving pockets of fluid which are compressed as the pocket moves from a radially outer position to a central position of scroll members 56 and 74. Non-orbiting scroll member 74 is mounted to main bearing housing 24 in any desired manner which will provide limited axial movement of non-orbiting scroll member 74. The specific manner of such mounting is not critical to the present invention.
Non-orbiting scroll member 74 has a centrally disposed discharge port 76 which is in fluid communication via an opening 78 in partition 20 with a discharge chamber 80 defined by cap 14 and partition 20. Fluid compressed by the compression chambers or moving pockets between scroll wraps 60 and 72 discharges into discharge chamber 80 through port 76 and opening 78. Non-orbiting scroll member 74 has in the upper surface thereof an annular recess 82 having parallel coaxial sidewalls within which is sealing disposed for relative axial movement an annular seal assembly 84 which serves to isolate the bottom of recess 82 so that it can be placed in fluid communication with a source of intermediate fluid pressure by means of a passageway 86. Non-orbiting scroll member 74 is thus axially biased against orbiting scroll member 56 by the forces created by discharge pressure acting on the central portion of non-orbiting scroll member 74 and the forces created by intermediate fluid pressure acting on the bottom of recess 82. This axial pressure biasing, as well as the various techniques for supporting non-orbiting scroll member 74 for limited axial movement, are disclosed in much greater detail in assignee's aforementioned U.S. Pat. No. 4,877,382.
Relative rotation of scroll members 56 and 74 is prevented by the usual Oldham coupling 88 having a pair of key slidably disposed in diametrically opposing slots in non-orbiting scroll member 74 and a second pair of keys slidably disposed in diametrically opposed slots in orbiting scroll member 56.
Compressor 10 is preferably of the “low side” type in which suction gas entering shell 12 is allowed, in part, to assist in cooling the motor. So long as there is an adequate flow of returning suction gas, the motor will remain within the desired temperature limits. When this flow ceases, however, the loss of cooling will cause motor protector 52 to trip and shut compressor 10 down.
The scroll compressor, as thus broadly described, is either known in the art or it is the subject matter of other pending applications for patent by Applicant's assignee. The details of construction which incorporate the principles of the present invention are those which deal with a unique fluid injection system identified generally by reference numeral 100. Fluid injection system 100 is used to inject refrigerant for cooling and/or increasing the capacity and efficiency of compressor 10.
Referring now to
Fluid injection passage 102 is a cross drilled feed hole which extends generally horizontal through non-orbiting scroll member 74 from a position on the exterior of non-orbiting scroll member 74 to a position where it communicates with fluid injection port 104. Fluid injection port 104 extends generally vertically from passage 102 through non-orbiting scroll member 74 to open into the enclosed spaces or pockets formed by wraps 60 and 72 as detailed below. Connecting tube 106 extends from fluid injection passage 102 to fluid injection port 108 where it extends through fluid injection port 108 to be sealingly secured to fluid injection fitting 110. While not shown, the source of the intermediate pressurized refrigerant fluid from a refrigeration system (not shown) is in communication with fluid injection fitting 110 through connecting tube 112 to provide the refrigerant fluid for injecting.
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The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.
