Abstract:
The compressor fittings, both suction and discharge, of a compressor can have braze rings positioned inside of the fittings as part of the compressor assembly. The braze ring can then be used by an installer to connect the compressor to corresponding suction and discharge lines of a system. The installer can insert the system tube or connection into the fitting and apply a torch until braze material can be seen exiting the joint around the system tube, which indicates the tube has been connected.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/756,702, filed Jan. 25, 2013, entitled APPARATUS AND METHOD FOR CONNECTING A COMPRESSOR TO A SYSTEM, which Application is incorporated by reference herein in its entirety. 
     
    
     BACKGROUND 
       [0002]    The application generally relates to methods and apparatuses for connecting a compressor to a corresponding system such as a vapor compression system. 
         [0003]    Aftermarket compressors (compressors installed into systems to replace a failed compressor) typically fail at a rate 3 to 4 times higher than original equipment manufacturer (OEM) initial installations. The high failure rate can be due to a variety of factors that can be present or occur in field installations. Some of the factors contributing to a high failure rate can include the presence of acids in the system from a motor burnout in the OEM compressor, the introduction of contaminants into the system during the installation process, the miswiring of the aftermarket compressor, overcharging the system with refrigerant during the installation process, or poor braze techniques when installing the aftermarket compressor. 
         [0004]    Poor braze techniques can lead to the failure of the aftermarket compressor in a number of different ways. One way a poor braze technique can lead to a compressor failure is that the braze technique does not result in a hermetic seal with the compressor and refrigerant leaks from the system which can result in compressor damage. Another way a poor braze technique can lead to compressor failure is that contaminants and/or debris can be introduced into the system during the brazing process and cause resultant damage to the compressor. 
         [0005]    Thus, what is needed is an apparatus and method for connecting a compressor to a corresponding system that makes tube brazing to the compressor easier, particularly for installers with poor braze techniques, while reducing the possibility of damage occurring to the compressor. 
       SUMMARY 
       [0006]    The present invention is directed to a compressor including a shell having an enclosed space, a compression mechanism positioned within the enclosed space of the shell, and a motor positioned within the enclosed space of the shell and connected to the compression mechanism by a shaft to power the compression mechanism. The compressor also includes at least one compressor fitting fastened in the shell to permit passage of refrigerant between inside and outside of the shell. The the at least one compressor fitting includes a braze ring positioned within the at least one compressor fitting. The braze ring includes brazing material to connect a tube to the at least one compressor fitting. 
         [0007]    The present invention is also directed to a method of connecting a compressor to a system. The method includes inserting a tube connected to a system into a fitting for a compressor having a braze ring position inside the fitting and heating a braze area of the fitting to melt a braze material of the braze ring. The method also includes inspecting an end of the fitting for braze material and stopping heating of the braze area upon braze material being identified around a circumference of the end of the fitting during the inspecting of the end. 
         [0008]    In the present application, the compressor fittings, both suction and discharge, have braze rings embedded in the corresponding fitting as part of the compressor assembly from the manufacturer. The installer of the compressor simply needs to insert the system tube or connection into the fitting and apply a torch until material, which can be a silver color, is seen exiting the joint around the system tube. 
         [0009]    One advantage of the present application is that it is much easier and more secure than typical brazing of the tube to the compressor using “stick” braze material. 
         [0010]    Other features and advantages of the present application will be apparent from the following more detailed description of the embodiments, taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  shows an embodiment of a compressor. 
           [0012]      FIG. 2  schematically shows an embodiment of a vapor compression system. 
           [0013]      FIG. 3  schematically shows another embodiment of a vapor compression system. 
           [0014]      FIG. 4  shows an embodiment of a braze ring for a suction fitting for a compressor. 
           [0015]      FIG. 5  shows an embodiment of a braze ring for a discharge fitting for a compressor. 
           [0016]      FIGS. 6 and 7  show different embodiments for holding a braze ring in a compressor fitting. 
           [0017]      FIG. 8  shows a partial cross-sectional view of an embodiment of a suction fitting positioned in a compressor. 
           [0018]      FIG. 9  shows an embodiment of a connection between a compressor fitting and a system connection. 
       
    
    
       [0019]    Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
       DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0020]      FIG. 1  shows an embodiment of a reciprocating compressor. However, in other embodiments, the compressor can be any suitable type of hermetic or semi-hermetic compressor including, but not limited to, a rotary compressor, screw compressor, swag link compressor, scroll compressor, spool compressor, centrifugal compressor, or turbine compressor. 
         [0021]    In  FIG. 1 , compressor  2  can have a suction port or fitting  14  that can be in fluid communication with an evaporator of a vapor compression system upon the connection of a suction line or conduit from the evaporator to the suction port  14 . The suction port  14  can be in fluid communication with a suction plenum  12  through one or more openings in a motor cap  13 . Refrigerant gas from the evaporator can enter the compressor  2  through the suction port  14  and then flows to the suction plenum  12  before being compressed. In one embodiment, the refrigerant gas from the suction port  14  can also fill the interior space of the compressor housing before flowing to the suction plenum  12 . 
         [0022]    The compressor  2  can use an electrical motor  18 . As shown in  FIG. 1 , motor  18  is an induction motor having a stator  20  and a rotor  22 . However, in other embodiments, any other suitable type of electrical motor may be used including, but not limited to, a switched reluctance (SR) motor or an electronically commutated permanent magnet motor (ECM). A shaft assembly  24  extends through the rotor  22 . The bottom end  26  of the shaft assembly  24  extends into an oil sump  405  and includes a series of apertures  27 . Connected to the shaft assembly  24  below the motor is a compression device  30 , such as a piston assembly as shown in  FIG. 1 . In  FIG. 1 , the piston assembly  30  has two pistons. A connecting rod  32  is connected to a piston head  34 , which moves back and forth within a cylinder  36 . The cylinder  36  includes a gas inlet port  38  and a gas discharge port  40 . Associated with these ports  38 ,  40  are associated suction valves and discharge valves. The gas inlet port  38  is connected to an intake tube  54 , which is in fluid communication with the suction plenum  12 . 
         [0023]    The motor  18  can be activated by a signal in response to the satisfaction of a predetermined condition, for example, an electrical signal from a thermostat when a preset temperature threshold is reached. While a thermostat is used as an example, it should be known that any type of device or signal may be used to activate the compressor  2 . When the compressor  2  is activated, electricity is supplied to the stator  20 , and the windings in the stator  20  cause the rotor  22  to rotate. Rotation of the rotor  22  causes the shaft assembly  24  to turn. When the shaft assembly  24  is turning, oil sump fluid in the oil sump  405  enters the apertures  27  in the bottom end  26  of the shaft and then moves upward through and along the shaft  24  to lubricate the moving parts of the compressor  2 . 
         [0024]    Rotation of the rotor  22  also causes reciprocating motion of the piston assembly  30 . As the assembly  30  moves to an intake position, the piston head  34  moves away from gas inlet port  38 , the suction valve opens and refrigerant fluid is introduced into an expanding cylinder  36  volume. The gas is pulled from the suction plenum  12  through the intake tube  54  to the gas inlet port  38  where the gas passes through the suction valve and is introduced into the cylinder  36 . When the piston assembly  30  reaches a first end (or top) of its stroke, shown by movement of the piston head  34  to the right side of the cylinder  36  of  FIG. 1 , the suction valve closes. The piston head  34  then compresses the refrigerant gas by reducing the cylinder  36  volume. When the piston assembly  30  moves to a second end (or bottom) of its stroke, shown by movement of piston head  34  to the left side of cylinder  36  of  FIG. 1 , a discharge valve is opened and the compressed refrigerant gas is expelled through the gas discharge port  40 . The compressed refrigerant gas flows from the gas discharge port  40  into a muffler  50  then through an exhaust or discharge tube  52  to a discharge port or fitting. The discharge port can be in fluid communication with a condenser upon the connection of a discharge line or conduit from the condenser to the discharge port. 
         [0025]    In one embodiment, the suction port or fitting  14  and the discharge port of fitting can be installed in a shell  98  of the compressor  2 . The suction port  14  and the discharge port can each be inserted through a corresponding opening in the shell  98  of the compressor  2  and then fastened to the shell  98 . In one embodiment, the suction port  14  and the discharge port can be fastened to the shell  98  by brazing or welding techniques to maintain a hermetic environment within the compressor shell  98 . However, any suitable technique, e.g., epoxy, adhesives, compression fit, etc., to fasten the suction port  14  and the discharge port to the shell  98  can be used so long as the hermetic environment within the compressor is maintained. 
         [0026]    The compressor  2  may be connected to a vapor compression system that is included in a heating, ventilation and air conditioning (HVAC) system, refrigeration system, chilled liquid system or other suitable type of system.  FIGS. 2 and 3  show different embodiments of vapor compression systems. In  FIG. 2 , vapor compression system  300  includes the compressor  2 , a condenser  304 , and an evaporator  306 , while in  FIG. 3 , vapor compression system  300  includes the compressor  2 , a reversing valve  350 , an indoor unit  354  and an outdoor unit  352 . 
         [0027]    The vapor compression system  300  can be operated as an air conditioning system, where the evaporator  306  is located inside a structure or indoors, i.e., the evaporator is part of indoor unit  354 , to provide cooling to the air in the structure and the condenser  304  is located outside a structure or outdoors, i.e., the condenser is part of outdoor unit  352 , to discharge heat to the outdoor air. The vapor compression system  300  can also be operated as a heat pump system, i.e., a system that can provide both heating and cooling to the air in the structure, with the inclusion of the reversing valve  350  to control and direct the flow of refrigerant from the compressor  2 . When the heat pump system is operated in an air conditioning mode, the reversing valve  350  is controlled to provide for refrigerant flow as described above for an air conditioning system. However, when the heat pump system is operated in a heating mode, the reversing valve  350  is controlled to provide for the flow of refrigerant in the opposite direction from the air conditioning mode. When operating in the heating mode, the condenser  304  is located inside a structure or indoors, i.e., the condenser is part of indoor unit  354 , to provide heating to the air in the structure and the evaporator  306  is located outside a structure or outdoors, i.e., the evaporator is part of outdoor unit  352 , to absorb heat from the outdoor air. 
         [0028]    In vapor compression system  300 , whether operated as a heat pump or as an air conditioner, the compressor  2  is driven by the motor  18  that is powered by a motor drive  104 . The motor drive  104  receives AC power having a particular fixed line voltage and fixed line frequency from AC power source  102  and provides power to the motor  18 . In another embodiment, the motor  18  can be powered directly from the AC power source  102 . The motor  18  used in the system  300  can be any suitable type of motor that can be powered by a motor drive  104 . 
         [0029]    Referring back to  FIGS. 2 and 3 , the compressor  2  compresses a refrigerant vapor and delivers the vapor to the condenser  304  through a discharge line (and the reversing valve  350  if configured as a heat pump). Some examples of refrigerants that may be used in vapor compression system  300  are: hydrofluorocarbon (HFC) based refrigerants, for example, R-410A, R-407C, R-404A, R-134a and R-32 (a component of R410A and R407C); hydrofluoro olefin (HFO) refrigerants, also known as “unsaturated HFCs,” such as R1234yf; inorganic refrigerants like ammonia (NH3), R-717 and carbon dioxide (CO2), R-744; hydrocarbon (HC) based refrigerants such as propane (R-290), isobutane (R-600a) or propene (R-1270), or any other suitable type of refrigerant. The refrigerant vapor delivered by the compressor  2  to the condenser  304  enters into a heat exchange relationship with a process fluid, e.g., air or water, and undergoes a phase change to a refrigerant liquid as a result of the heat exchange relationship with the process fluid. The condensed liquid refrigerant from the condenser  304  flows through an expansion device to the evaporator  306 . 
         [0030]    The condensed liquid refrigerant delivered to the evaporator  306  enters into a heat exchange relationship with another process fluid, e.g., air or water, and undergoes a phase change to a refrigerant vapor as a result of the heat exchange relationship with the process fluid. The vapor refrigerant in the evaporator  306  exits the evaporator  306  and returns to the compressor  2  by a suction line (and the reversing valve arrangement  350  if configured as a heat pump) to complete the cycle. In other embodiments, any suitable configuration of the condenser  304  and the evaporator  306  can be used in the system  300 , provided that the appropriate phase change of the refrigerant in the condenser  304  and evaporator  306  is obtained. For example, if air is used as the process fluid to exchange heat with the refrigerant in the condenser  304  or the evaporator  306 , then one or more fans can be used to provide the necessary airflow through the condenser  304  or evaporator  306 . The motors for the one or more fans may be powered directly from the AC power source  102  or a motor drive, such as motor drive  104 . 
         [0031]      FIGS. 4-8  show embodiments of a braze ring in compressor suction fittings and compressor discharge fittings. A braze ring  60  can be positioned into one or both of the suction fitting or port  14  (see  FIG. 4 ) or discharge fitting or port  16  (see  FIG. 5 ), i.e., the compressor fittings, of the compressor  2  by the manufacturer. The braze ring  60  positioned in the compressor fitting(s) can be selected to have an appropriate size to provide sufficient brazing material or brazing alloy for the corresponding diameters of the fitting and connection and the area to be brazed. The braze ring  60  can be held in position on an inner surface  17  of the compressor fitting by any suitable technique that can maintain the braze ring in the desired position or location until the compressor  2  is installed into a corresponding system. 
         [0032]    In  FIGS. 4 and 5 , a compression (or frictional) fit of the braze ring  60  is used to hold the braze ring  60  in the fitting  14 ,  16 . As shown in  FIG. 6 , the braze ring  60  can reside or be embedded in a circumferential groove  62  in the internal surface  17  of the fitting  14  to hold the braze ring  60  in position. As shown in  FIG. 7 , the blaze ring  60  can be held in position by one or more protrusions, shoulders or flares  64  on the internal surface  17  of the discharge fitting  16  to hold the braze ring  60  in position. The protrusions, shoulders or flares  64  extend circumferentially around the inner surface  17  of the discharge fitting  16 . However, in other embodiments, several individual protrusions  64  can be positioned at different locations around the inner surface  17  of the discharge fitting  16  to hold the braze ring  60  in position. 
         [0033]      FIG. 8  shows an alternate embodiment of a suction fitting with a braze ring. The suction fitting  80  can have a first portion  82  that is substantially cylindrical and a second portion  84  that expands in diameter from the first portion  82 . The second portion  84  can be attached in the compressor housing to form the hermetic seal for the compressor  2 . The second portion  84  can have louvers  86  to direct refrigerant flow once it enters compressor  2  and a suction filter  88  to remove debris from the refrigerant flow entering the compressor  2 . 
         [0034]    In one embodiment, the braze ring  60  can be placed a predetermined distance from the end of the corresponding fitting. The predetermined distance for the placement of the braze ring  60  can be in the range of 0.25 inches to 1.5 inches in one embodiment. In other embodiments, the braze ring  60  can be placed at the same predetermined distance or different predetermined distances from the ends of the suction fittings  14  and the discharge fittings  16 . 
         [0035]    In another embodiment, more than one braze ring  60  can be placed in a suction fitting  14  or discharge fitting  16  if additional brazing material is required for the connection to the system. The braze rings  60  can be placed or positioned next to each other or spaced apart by a predetermined distance. 
         [0036]    In still another embodiment, the braze ring can be a SilFos® ring with a brazing alloy having 15% silver (Ag). 
         [0037]    The compressor  2  can be connected to a system using the following process. First, a compressor fitting  90  and a system connection or tube  92  can each be cleaned to remove any dirt and prepare the corresponding surfaces for brazing. Next, the system connection  92  can be inserted into the compressor fitting  90  until the system connection  92  contacts the braze ring (or a protrusion or shoulder if used to hold the braze ring). The corresponding braze area  94 , i.e., the area of overlap between the compressor fitting  90  and the system connection  92 , can be uniformly heated starting at the braze ring and extending over the brazing area  94 . Finally, the brazing process is completed when braze material  96  can be seen around the entire circumference of the system connection  92  at the end of the compressor fitting  90 , i.e., the joint between the system connection  92  and the compressor fitting  90 .  FIG. 9  shows an embodiment of a connection between a compressor fitting  90  and a system connection  92 . 
         [0038]    As would be appreciated by those of ordinary skill in the pertinent art, the functions of several elements of the present application may, in alternative embodiments, be carried out by fewer elements, or a single element. Similarly, in some embodiments, any functional element may perform fewer, or different, operations than those described with respect to the exemplary embodiment. Also, functional elements shown as distinct in the drawings may be incorporated within other functional elements, separated in different hardware or distributed in various ways in a particular implementation. Further, relative size and location are merely somewhat schematic and it is understood that not only the same but many other embodiments could have varying depictions. 
         [0039]    All relative descriptions herein such as above, below, left, right, up, and down are with reference to the Figures, and not meant in a limiting sense. Relative descriptions such as inner and inward are with reference to being a direction toward the interior of a compressor shell whereas outer and outward are a direction away from the compressor. The shown assemblies can be understood as providing exemplary features of varying detail of certain embodiments, and therefore, components, modules, elements, and/or aspects of the drawings can be otherwise added to, combined, interconnected, sequenced, separated, interchanged, positioned, and/or rearranged without materially departing from the disclosed systems or methods. Additionally, the shapes and sizes of components are also exemplary and unless otherwise specified, can be altered without materially affecting or limiting the disclosed technology. 
         [0040]    It is important to note that the construction and arrangement of the present application as shown in the various exemplary embodiments is demonstrative only. Although only a few embodiments have been described in detail in this application, those who review this application can readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters (e.g., temperatures, pressures, etc.), mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described in the application. For example, elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. Accordingly, all such modifications are intended to be included within the scope of the present application. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. In the claims, any means-plus-function clause is intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the exemplary embodiments without departing from the scope of the present application. Accordingly, the present application is not limited to a particular embodiment, but extends to various modifications that nevertheless fall within the scope of the appended claims. 
         [0041]    Furthermore, in an effort to provide a concise description of the exemplary embodiments, all features of an actual implementation may not have been described (i.e., those unrelated to the presently contemplated best mode of carrying out the invention, or those unrelated to enabling the invention). It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation specific decisions may be made. Such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure, without undue experimentation.