Patent Abstract:
A scroll-type compressor is provided in an inclined or inverted position with an oil sump disposed adjacent to a gas inlet of the scroll wraps to allow droplets of oil to be entrained in the gas being compressed so that the oil droplets in the gas can cool the scroll wraps. An oil injection fitting also extends through the compressor shell and communicates lubricating oil to a lubrication passage in the crankshaft for providing lubricant to the bearings of the crankshaft of the compressor and other components. The oil injection fitting is supplied with lubricant from an externally disposed source.

Full Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates generally to scroll-type machines. More particularly, the present invention relates to a scroll-type compressor having an oil sump adjacent to the scroll wraps  
       BACKGROUND AND SUMMARY OF THE INVENTION  
       [0002]     Scroll machines in general, and particularly scroll compressors, are often disposed in a hermetic shell which defines a chamber within which is disposed a working fluid. A partition within the shell often divides the chamber into a discharge pressure zone and a suction pressure zone. In a low-side arrangement, a scroll assembly is located within the suction pressure zone for compressing the working fluid. Generally, these scroll assemblies incorporate a pair of intermeshed spiral wraps, one or both of which are caused to orbit relative to the other so as to define one or more moving chambers which progressively decrease in size as they travel from an outer suction port towards a center discharge port. An electric motor is normally provided which operates to cause this relative orbital movement.  
         [0003]     The partition within the shell allows compressed fluid exiting the center discharge port of the scroll assembly to enter the discharge pressure zone within the shell while simultaneously maintaining the integrity between the discharge pressure zone and the suction pressure zone. This function of the partition is normally accomplished by a seal which interacts with the partition and with the scroll member defining the center discharge port.  
         [0004]     The discharge pressure zone of the hermetic shell is normally provided with a discharge fluid port which communicates with a refrigeration circuit or some other type of fluid circuit. In a closed system, the opposite end of the fluid circuit is connected with the suction pressure zone of the hermetic shell using a suction fluid port extending through the shell into the suction pressure zone. Thus, the scroll machine receives the working fluid from the suction pressure zone of the hermetic shell, compresses the working fluid in the one or more moving chambers defined by the scroll assembly, and then discharges the compressed working fluid into the discharge pressure zone of the compressor. The compressed working fluid is directed through the discharge port through the fluid circuit and returns to the suction pressure zone of the hermetic shell through the suction port.  
         [0005]     Typically, scroll-type compressors have been designed as either a vertical or a horizontal scroll compressor. A primary difference between the vertical and horizontal scroll compressor designs stems from the fact that the lubrication sump and delivery systems have needed to be specifically adapted for a vertical or horizontal configuration. Commonly assigned U.S. Pat. No. 6,428,296 discloses a typical vertical-type scroll compressor modified to be a horizontal-type scroll compressor by providing a unique oil injection fitting for delivering oil to the existing lubricant passage in the crank shaft of the compressor system from an external oil source. The present invention provides a negatively inclined or inverted scroll compressor wherein the muffler/partition plate defines part of the oil sump within the hermetic shell. The ability to incline or invert the scroll compressor allows the amount of oil accumulated in the sump to be reduced and allows oil in the sump to be directly ingested through the scroll wraps for cooling of the wraps. Furthermore, space constraints within the surrounding environment may dictate whether the compressor needs to be disposed in an inclined or vertical position.  
         [0006]     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood however that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0008]      FIG. 1  is a vertical sectional view through the center of a negatively inclined scroll compressor in accordance with the present invention;  
         [0009]      FIG. 2  is a cross-sectional view taken along line  2 - 2  of  FIG. 1 ;  
         [0010]      FIG. 3  is a schematic view of a system layout utilizing the negatively inclined scroll compressor with an oil injection fitting according to the principles of the present invention;  
         [0011]      FIG. 4  is a schematic view of a system layout according to a second embodiment of the present invention;  
         [0012]      FIG. 5  is a schematic view of a system layout according to a third embodiment of the present invention;  
         [0013]      FIG. 6  is a vertical sectional view through the center of an inverted scroll compressor in accordance with the present invention; and  
         [0014]      FIG. 7  is a detailed cross-sectional view of the oil injection fitting supplying oil to the scroll compressor according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0015]     While the present invention is suitable for incorporation with many different types of scroll machines, for exemplary purposes, it will be described herein incorporated in a scroll compressor of the general structure illustrated in  FIG. 1  (the vertical-type compressor shown prior to conversion to a negatively inclined compressor is a ZB45 compressor commercially available from Copeland Corporation, Sidney, Ohio.) Referring now to the drawings, and in particular to  FIG. 1 , a compressor  10  is shown which comprises a generally cylindrical hermetic shell  12  having welded at one end thereof a cap  14 . Cap  14  is provided with a discharge fitting  18  which may have the usual discharge valve therein. Other major elements affixed to the shell include an inlet fitting  21 , a transversely extending partition  22  which is welded about its periphery at the same point that cap  14  is welded to cylindrical shell  12 . A discharge chamber  23  is defined by cap  14  and partition  22 .  
         [0016]     A main bearing housing  24  and a second bearing housing  26  having a plurality of radially outwardly extending legs are each secured to the cylindrical shell  12 . A motor  28  which includes a rotor  30  is supported within the cylindrical shell  12  between main bearing housing  24  and second bearing housing  26 . A crank shaft  32  having an eccentric crank pin  34  at one end thereof is rotatably journaled in a bearing  36  in main bearing housing  24  and a second bearing  38  in second bearing housing  26 .  
         [0017]     Crank shaft  32  has, at a second end, a relatively large diameter concentric bore which communicates with a radially outwardly smaller diameter bore extending therefrom to the first end of crankshaft  32 .  
         [0018]     Crank shaft  32  is rotatably driven by electric motor  28  including rotor  50  and stator windings  48  passing therethrough. The rotor  50  is press fitted on crank shaft  32  and may include counterweights mounted thereon for balancing.  
         [0019]     A first surface of the main bearing housing  24  is provided with a flat thrust bearing surface  56  against which is disposed an orbiting scroll  58  having the usual spiral vane or wrap  60  on a first surface thereof. Projecting from the second surface of orbiting scroll  58  is a cylindrical hub  61  having a journal bearing  62  therein in which is rotatably disposed a drive bushing  36  having an inner bore  66  in which crank pin  34  is drivingly disposed. Crank pin  34  has a flat on one surface which drivingly engages a flat surface (not shown) formed in a portion of bore  66  to provide a radially compliant driving arrangement, such as shown in assignee&#39;s U.S. Pat. No. 4,877,382, the disclosure of which is hereby incorporated herein by reference.  
         [0020]     An oldham coupling  68  is disposed between orbiting scroll  58  and bearing housing  24 . Oldham coupling  68  is keyed to orbiting scroll  58  and a non-orbiting scroll  70  to prevent rotational movement of orbiting scroll member  58 . Oldham coupling  68  is preferably of the type disclosed in assignee&#39;s U.S. Pat. No. 5,320,506, the disclosure of which is hereby incorporated herein by reference. A floating seal  71  is supported by the non-orbiting scroll  70  and engages a seat portion  73  mounted to the partition  22  for sealingly dividing the intake and discharge chambers  75  and  23 , respectively.  
         [0021]     Non-orbiting scroll member  70  is provided having a wrap  72  positioned in meshing engagement with wrap  60  of orbiting scroll  58 . Non-orbiting scroll  70  has a centrally disposed discharge passage  74  defined by a base plate portion  76 . Non-orbiting scroll  70  also includes an annular hub portion  77  which surrounds the discharge passage  74 . A dynamic discharge valve or read valve can be provided in the discharge passage  74 .  
         [0022]     An oil injection fitting  80 , as best shown in  FIG. 7 , is provided through the second cap  82  which is connected to the shell  12 . The oil injection fitting  80  is threadedly connected to a fitting  84  which is welded within an opening  86  provided in the bottom cap  82 . The fitting  84  includes an internally threaded portion  88  which is threadedly engaged by an externally threaded portion  90  provided at one end of the oil injection fitting  80 . A nipple portion  92  extends from the externally threaded portion  90  of the oil injection fitting  80 . The nipple portion  92  extends within an opening provided in a snap ring  94  which is disposed in the lower bearing  26 . The snap ring  94  holds a disk member  96  in contact with the lower end of the crankshaft  32 . Disk member  96  includes a hole  98  which receives, with a clearance, the end of the nipple portion  92  therein. The oil injection fitting includes an internal oil passage  100  extending longitudinally therethrough which serves as a restriction on the oil flow. The oil injection fitting  80  includes a main body portion  102  which is provided with a tool engaging portion  104  (such as a hex shaped portion which facilitates the insertion and removal of the fitting  80  by a standard wrench). The oil injection fitting  80  further includes a second nipple portion  106  extending from the main body  102  in a direction opposite to the first nipple portion  92 . The second nipple portion  106  is adapted to be engaged with a hose or tube  108  which supplies oil to the fitting  80 . The oil that passes through the fitting  80  lubricates the bearings  36 ,  38  and accumulates in the compressor sump.  
         [0023]     As shown in  FIG. 1 , the compressor  10  is negatively inclined so that the partition plate  22  defines part of the sump for receiving oil therein. The oil level is preferably disposed just below the gas inlet  140  provided on the lower side of the scroll members  58 ,  70  (best shown in  FIG. 2 ) so that working fluid entering the scroll inlet  140  can entrain the oil for providing cooling and lubrication to the internal wraps of the scroll-type compressor. The oil level within the sump is self regulated such that as the oil level reaches the gas inlet  140 , the oil is ingested into the inlet and subsequently expelled from the compressor to be separated, as will be described with reference to  FIGS. 3-5 . Furthermore, because the oil is in contact with the partition plate, the oil acts as a coolant on the partition plate. By maintaining the compressor  10  in an inclined position as illustrated in  FIG. 1 , the amount of oil needed to maintain the level close to the gas inlets  140 ,  142  of the scroll wraps can be minimized so that a reduced amount of oil needs to be maintained within the shell  12 . The oil injection fitting  80  provides lubricant to the bearings  26 ,  36  for the driveshaft  32  via the internal oil passages in the driveshaft  32 . The oil that is ingested through the gas inlet  140  of the scroll members  58 ,  70  and carried out through the discharge port is separated by an oil separator and may be cooled by a heat exchanger prior to being re-injected through oil fitting  80 , as will be described in greater detail with respect to  FIG. 3  below.  
         [0024]     As illustrated in  FIG. 6 , the scroll compressor can similarly be inverted so that the partition plate  22  is disposed at the bottom of the sump. The oil level can be maintained at or just above the lower edge of the gas inlet opening  140  of the scroll members  58 ,  70 . Thus, a controlled amount of oil is received between the scroll wrap during operation of the scroll compressor utilized in the inverted position as illustrated in  FIG. 6 . In either the inclined or inverted positions, the amount of oil necessary to maintain the oil level at the gas inlet opening  140  can be minimized. Furthermore, the oil passing through the crankshaft and bearings and disposed in the sump also absorbs heat from the motor.  
         [0025]     With reference to  FIG. 3 , a system layout is shown including two compressors  10 A,  10 B which are both preferably of the negatively inclined or inverted type shown in  FIG. 1  or  FIG. 6 , respectively. The system is provided with an oil separator  112  which receives compressed gases from the discharge fittings  18  of compressors  10 A,  10 B. The oil separator  112  can be of any type known in the art. The oil separator  112  separates the oil from the discharge gases and provides the discharged gases via passage  114  to a desired system. A return oil passage  116  with a heat exchanger  117  is connected to the oil separator and communicates with a pair of electronic solenoids  118 ,  120 . The electronic solenoids  118 ,  120  prevent loss of oil to the compressors from the separator after the compressors  10 A,  10 B are shut down due to pressure that is built up in the passage  114 , oil separator  112 , and return oil passage  116 . As an alternative, the solenoid valves  118  can be eliminated if the discharge fitting  18  is not provided with a check valve. In that case, built-up pressure can be released back through the discharge fitting  18  which may result in reverse rotation of the compressor in which the pressure is relieved. In the case where a floating seal is provided, the floating seal is disengaged, thus, allowing the release of the pressure build-up. Capillary tubes  119  are provided to restrict flow to provide oil control to prevent excessive oil flow over the full operating range of the compressors  10 A,  10 B. The capillary tubes  119  can be used in addition to or as an alternative to the restriction oil passage  100  provided in the oil injection fitting  80 . Oil is delivered through the fittings  80  and into the concentric bore provided in the crankshafts  32  of the compressors  10 A,  10 B. The concentric bore communicates with a radially outward smaller diameter bore extending therefrom to the second end of the crankshaft  32 . From the second end of the crankshaft  32 , oil is distributed to the bearings and to the scroll members  58 ,  70 , as is known in the art.  
         [0026]      FIG. 4  shows a system layout according to a second embodiment of the present invention. The system layout of  FIG. 4  includes first and second compressors  10 A,  10 B which are provided with their own oil separators  130 A,  130 B, respectively. Each of the oil separators  130 A,  130 B are connected to a passage  114  for supplying discharge gases thereto. The oil separators  130 A,  130 B are connected to an oil sump  132  for providing the separated oil thereto. A return oil passage  116  with a heat exchanger  117  is connected to the oil sump  132  for returning oil to the first and second compressors  10 A,  10 B. It should be noted that the heat exchanger  117  can be provided upstream, downstream, or integral with the oil sump  132 . Electronic solenoids  118 ,  120  are provided in the respective return oil passages connected to the compressors  10 A,  10 B. Again, capillary tubes  119  can be provided to restrict the oil flow to the oil injection fittings  80  of the compressors  10 A,  10 B. The system layout of  FIG. 4  allows the use of standard oil separators and can be utilized with an air compressor or a natural gas compressor system.  
         [0027]      FIG. 5  shows a single compressor system including a compressor  10  having a discharge passage  18  connected to an oil separator  112 . An oil return passage  116  with a heat exchanger  117  is connected to the oil separator  112  for returning oil to the oil injection fitting  80  of the compressor  10 . A capillary tube  119  is provided in the oil return passage  116  for restricting oil flow to the compressor. The capillary tube  119  can be used as an alternative or in addition to the restriction passage  100  provided in the oil injection fitting  80 .  
         [0028]     According to the present invention, a vertical-type compressor can be modified to become a negatively inclined compressor by adding an oil injection fitting and an external oil separator system. In addition, the modification of the vertical-type compressor to a negatively inclined compressor has a very low additional cost and has virtually the same performance as the vertical compressor being modified.  
         [0029]     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

Technology Classification (CPC): 5