Abstract:
A compressor ( 20 ) has a case ( 22 ) and a pair of feet ( 70 A,  70 B). The feet are alternatively mountable in a first orientation and a second orientation orthogonal to the first orientation.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    Benefit is claimed of U.S. patent application Ser. No. 61/696,716, filed Sep. 4, 2012, and entitled “Refrigeration Compressor Feet Mounting”, the disclosure of which is incorporated by reference herein in its entirety as if set forth at length. 
     
    
     BACKGROUND 
       [0002]    The present disclosure relates to refrigeration compressors. More particularly, it relates to reciprocating piston compressor mounting. 
         [0003]    A variety of refrigerant compressor configurations are in common use. Among these configurations are: screw compressors; scroll compressors; and reciprocating piston compressors. One particular subfield of refrigeration systems is chiller systems where one or more compressors are mounted on a rack. Rack mounting of compressors may be used in other applications such as central compressors for distributed retail display cabinets. 
         [0004]    Mounting is often on parallel mounting rails of the rack. During installation and removal of compressors, there may be a tendency of the compressor to partially fall between rails. 
       SUMMARY 
       [0005]    One aspect of the disclosure involves a compressor having a case and a pair of feet. The feet are alternatively mountable in a first orientation and a second orientation orthogonal to the first orientation. 
         [0006]    In various implementations, the compressor may be a reciprocating compressor. An electric motor may be within the case for driving compression or external to the case. The feet may comprise bent sheet metal strips. The compressor may comprise a casting with internally-threaded mounting features. The feet may comprise complementary mounting features. The case internally threaded mounting features may include a first pair laterally spaced apart and a second pair laterally spaced apart and longitudinally spaced apart from the first pair. The feet complementary mounting features may comprise: a pair of holes mountable, respectively, to the first pair of internally threaded mounting features or the second pair of internally threaded mounting features in the first orientation; and at least two further holes mountable, in the second orientation, respectively to one of the internally threaded mounting features of the first pair and one of the internally threaded mounting features of the second pair. A first hole of said at least two further holes in the feet may be between the holes of the pair. The first hole may be exactly between the pair. The case may further comprise a shared boss bearing the mounting features. The feet may be secured to support rails, spanning a gap between the rails. 
         [0007]    Other aspects of the disclosure involve a refrigeration system including such a compressor. The refrigeration system may include a recirculating flowpath through the compressor. A first heat exchanger may be positioned along the flowpath downstream of the compressor. An expansion device may be positioned along the flowpath downstream of the first heat exchanger. A second heat exchanger may be positioned along the flowpath downstream of the expansion device. The refrigerant charge may comprise at least 50% carbon dioxide by weight. The system may be a refrigerated transport system. The refrigerated transport system may further comprise a container. The second heat exchanger may be positioned to cool an interior of the container. 
         [0008]    The system may be a fixed refrigeration system. The fixed refrigeration system may further comprise multiple refrigerated spaces. There may be a plurality of said second heat exchangers, each being positioned to cool an associated such refrigerated space. 
         [0009]    Other aspects of the disclosure involve methods of manufacture/use of a plurality of the compressors. With a first said compressor, the pair of feet are mounted in the first orientation; and with a second said compressor, the pair of feet are mounted in the second orientation, the second compressor&#39;s case and feet being identical/interchangeable to the first compressor&#39;s case and feet. 
         [0010]    The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is an exploded view of a compressor with feet in a longitudinal orientation. 
           [0012]      FIG. 2  is a bottom view of the compressor of  FIG. 1 . 
           [0013]      FIG. 3  is a further view of the compressor of  FIG. 1  removably and replaceably mounted to a plurality of rails. 
           [0014]      FIG. 4  is a bottom view of the compressor with the feet installed in a first transverse orientation. 
           [0015]      FIG. 5  is a bottom view of the compressor with the feet installed in a second transverse orientation. 
           [0016]      FIG. 6  is a bottom view of a foot of the compressor. 
           [0017]      FIG. 7  is an end view of the foot. 
           [0018]      FIG. 8  is a schematic view of a refrigeration system. 
           [0019]      FIG. 9  is a schematic view of a fixed commercial refrigeration system. 
       
    
    
       [0020]    Like reference numbers and designations in the various drawings indicate like elements. 
       DETAILED DESCRIPTION 
       [0021]      FIGS. 1 and 2  show an exemplary compressor  20 . The compressor  20  has a housing (case) assembly  22 . The exemplary compressor includes an electric motor  24  (e.g., having an axis  500  which also forms a compressor axis). The exemplary case  22  has a suction port (inlet)  26  ( FIG. 2 ) and a discharge port (outlet)  28 . The exemplary compressor is a reciprocating compressor wherein the housing defines a plurality of cylinders in a cylinder head section  30  of the housing. Each cylinder accommodates an associated piston (not shown) mounted for reciprocal movement at least partially within the cylinder. Exemplary multi-cylinder configurations include: in-line; V (vee); and horizontally opposed. Each of the cylinders includes a suction location and a discharge location. For example, the cylinders may be coupled in parallel so that the suction location is shared/common suction plenum fed by the suction port  26  and the discharge location is a shared/common discharge plenum feeding the discharge port  28 . In other configurations, the cylinders may share suction locations/conditions but have different discharge locations/conditions. In other configurations, the cylinders may be in series. An exemplary fluorocarbon-based refrigerant is R- 410 A. An exemplary carbon dioxide (CO 2 )-based (e.g., at least 50% CO 2  by mass/weight) refrigerant is R-744. Other refrigerants and other compressor configurations or types may be used. 
         [0022]    The exemplary case includes a lower end or bottom  40  formed in a casting  42  (e.g., aluminum alloy, iron or steel). The casting includes a plurality of mounting features for mounting the compressor. Exemplary mounting features are internally threaded holes in bosses. As is seen in the example, several are merged.  FIG. 1  shows a configuration wherein a pair of left and right forward mounting features  50 A and  50 B therebehind, and a second pair of intermediate mounting features  52 A and  52 B yet therebehind are all formed on a single island or super boss  44 ; whereas the rearmost pair of mounting features  54 A and  54 B are formed on a rear boss  46 . The superboss also includes a a single forwardmost tooling hole  48  (initially cast and machined and used to register the casting for further machining operations). Alternative mounting features include bores receiving press-fit studs. 
         [0023]    A pair of feet  70 A and  70 B (collectively or generically individually “ 70 ”) may be mounted to the mounting features. Exemplary mounting is via fasteners (e.g., bolts  60  with washers  62 ) extending through apertures in the feet. As is discussed further below,  FIGS. 1-3  show one exemplary use configuration in which the feet are mounted longitudinally (parallel to the axis  500 ). In this configuration,  FIG. 3  shows the feet bolted to support rails  64  and  65  of the environmental structure (e.g., compressor rack). The exemplary compressor rack has a forward transverse rail  64  and an aft transverse rail  65  and the forward end portions of the feet are secured to the forward rail and aft end portions of the feet are secured to the aft rail (e.g., via bolts  66  with washers  67  (discussed further below)). A series of such compressors may be mounted in an array along a common pair of such rails. 
         [0024]    As is discussed further below, the configuration of  FIG. 2  involves the foot  70 A mounted to the pair of features  50 A and  52 A and the foot  70 B mounted to the pair of features  50 B and  52 B so that the feet are essentially parallel to the compressor axis  500 . As is discussed further below, the exemplary feet and mounting features provide for alternative transverse mounting of the feet. Transverse mounting may be useful with longitudinal rack rails. By maintaining the feet transverse to the rails, stability may be improved by reducing the tendency of the compressor to partially fall between or aside the rails and preventing the feet sides from catching on the rail sides. 
         [0025]      FIGS. 4 and 5  show two exemplary such transverse feet options wherein the feet are mounted transversely using the mounting feature pairs  50 A and  50 B and  52 A and  52 B (see  FIG. 1 ). With the exemplary feet, there are several different orientation combinations as is discussed further below. In this exemplary situation, the rack mounting rails  68  and  69  are shown as longitudinal. 
         [0026]      FIGS. 6 and 7  show one of the feet  70 . The exemplary feet  70  are identical to each other (as opposed to being non-identical mirror images). The exemplary feet are elongate and are formed from a bent strip of bar stock (or cut in strips from a larger sheet). The exemplary feet extend from a first end  72  to a second end  73  and have respective first and second edges  74  and  75 . The exemplary edges  74  and  75  may be formed by edges of the bar stock (e.g., aluminum or steel). The exemplary feet each have a first face  76  and a second face  77  (e.g., formed by opposite faces of the strip or bar stock). The exemplary feet are formed with first and second flat flange portions  78  and  79  respectively extending inward from the edges  74  and  75  and joined by a nearly S-curved transition portion  80  to offset the flange portions  78  and  79  from each other in a generally parallel relationship by a height H 1 . An overall height is shown as H 2  which is merely H 1  plus the bar/strip thickness T 1 . An overall length is L 1  and an overall width is W 1 . Alternative constructions include cast or forged feet. 
         [0027]    In the exemplary embodiment, the flange  78  has an array of mounting features shown as mounting holes  81 ,  82 ,  83 ,  84 , and  85  each having an associated axis  520 . Various combinations of these are complementary to various combinations of the compressor mounting features to permit the various mounting orientations discussed herein. In the exemplary implementation, the hole  83  is centrally positioned and the inboard or intermediate pair of adjacent holes  82 ,  84  are evenly spaced therefrom as are the outboard/distal/end holes  81 ,  85 . An exemplary spacing between the intermediate pair of holes  82 ,  84  is shown as S 1  An exemplary separation between the center hole  83  and end holes  81 ,  85  is shown as S 2 . The exemplary holes  81 - 85  are parallel to and in line with each other and are circular of a shared diameter. 
         [0028]    Similarly, the second flange  79  may have a plurality of mounting features (e.g., holes) for mounting to the environmental structure (e.g., the rack rails). Exemplary features are a pair of mounting holes  91  and  92  each having an axis  522  and separated by a distance S 3 . 
         [0029]    The exemplary foot is thus a mirror image across a transverse centerplane in which the axis  520  of the hole  83  lies. 
         [0030]    To allow for the alternative mounting, the exemplary spacing between the left and right compressor mounting holes  50 A,  50 B and  52 A,  52 B is also S 1  so that the feet may be mounted via holes  82  and  84  in the transverse conditions. As mentioned above, there are four possible combinations of mounting the feet transversely depending upon whether the edge  75  (the lower edge along the flange  79  for mounting to the environmental structure) faces forward or aft for each of the two feet. In general, the broader stance of  FIG. 5  might be preferred. However, other considerations may influence orientation. 
         [0031]    In the exemplary compressor, the mounting feature pairs  50 A,  50 B and  52 A,  52 B are relatively forward on the compressor with the feature pair  52 A,  52 B being nearly geometrically central. For the longitudinal feet orientation of such a compressor, it may be desired to mount the feet longitudinally off center. Accordingly, rather than dimensioning the system such that the same foot holes are used to mount the feet longitudinally as were used in the transverse mounting, the exemplary system mounts the feet longitudinally using the center hole  83  and one of the end holes  81 ,  85 . In this example, the center hole of each foot is mounted to the intermediate mounting feature  52 A or  52 B and one of the end holes is mounted to the front mounting feature  50 A,  50 B. Again, there are several possible orientations of whether the feet lower edges face outward or inward. However, having the broadest stance favors the outward orientation of both feet as is shown in  FIGS. 1-3 . 
         [0032]    Among other variations, resilient isolators (e.g., cylindrical elastomeric bodies) may intervene between the feet and the rails. A variety of isolation mounts including such elastomers and/or metallic compression springs are known as are a variety of mounting means (e.g., simple through-bolting of the feet to the rails or separate attachment of the isolation mount to the rails and the feet to the isolation mount). 
         [0033]    Yet other variations include use of the other mounting features. For greater support, an adaptor may be used to mount one of the transverse feet to the aft mounting features  54 A and  54 B. 
         [0034]      FIG. 8  shows an exemplary refrigeration system  120  including the compressor  20 . The system  120  includes a system suction location/condition  150  at the suction port  26 . A refrigerant primary flowpath  152  proceeds downstream from the suction location/condition  150  through the compressor cylinders in parallel to be discharged from a discharge location/condition  154  at the discharge port  28 . The primary flowpath  152  proceeds downstream through the inlet of a first heat exchanger (gas cooler/condenser)  156  to exit the outlet of the gas cooler/condenser. The primary flowpath  152  then proceeds downstream through an expansion device  162 . The primary flowpath  152  then proceeds downstream through a second heat exchanger (evaporator)  164  to return to the suction condition/location  150 . 
         [0035]    In a normal operating condition, a recirculating flow of refrigerant passes along the primary flowpath  152 , being compressed in the cylinders. The compressed refrigerant is cooled in the gas cooler/condenser  156 , expanded in the expansion device  162 , and then heated in the evaporator  164 . In an exemplary implementation, the gas cooler/condenser  156  and evaporator  164  are refrigerant-air heat exchangers with associated fan ( 170 ;  172 )-forced airflows ( 174 ;  176 ). The evaporator  164  may be in the refrigerated space or its airflow may pass through the refrigerated space Similarly, the gas cooler/condenser  156  or its airflow may be external to the refrigerated space. 
         [0036]    Additional system components and further system variations are possible (e.g., multi-zone/evaporator configurations, economized configurations, and the like). Exemplary systems include refrigerated transport units and fixed commercial refrigeration systems. 
         [0037]    An exemplary fixed commercial refrigeration system  250  ( FIG. 9 ) includes one or more central compressors  20  and heat rejection heat exchangers  156  (e.g., outside/on a building  255 ) commonly serving multiple refrigerated spaces  256  (e.g., of retail display cabinets  258  in the building). Each such refrigerated space may have its own heat absorption heat exchanger  164 ′ and expansion device  162 ′ (or there may be a common expansion device). Other rack-mount situations include building heating, ventilation and air conditioning (HVAC). 
         [0038]    The compressor may be manufactured via otherwise conventional manufacturing techniques. 
         [0039]    Although an embodiment is described above in detail, such description is not intended for limiting the scope of the present disclosure. It will be understood that various modifications may be made without departing from the spirit and scope of the disclosure. For example, when implemented in the reengineering of an existing compressor configuration, details of the existing configuration may influence or dictate details of any particular implementation. Accordingly, other embodiments are within the scope of the following claims.