Patent Publication Number: US-6708519-B1

Title: Accumulator with internal desiccant

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to an accumulator within a heating, ventilation, air-conditioning and refrigeration (HVAC&amp;R) system, and more particularly to an accumulator that includes a desiccant and is integral with the compressor of the HVAC&amp;R system. 
     Air-conditioning systems commonly employ an accumulator to ensure delivery of refrigerant in its vapor state to the compressor to avoid damaging the compressor. The accumulator delivers refrigerant vapor by typically employing a tube which extends from the upper portion of the accumulator to the lower portion, the tube further extending from the lower portion of the accumulator to a suction opening to the compressor. A mix of liquid and vapor refrigerant entering the top portion of the accumulator is directed around the opening in the tube for circulation within the body of the accumulator. Liquid refrigerant is separated from vapor refrigerant which is permitted to flow to the compressor, while the liquid refrigerant is collected and retained within the accumulator. In certain system configurations, the accumulator may be housed within the compressor shell. 
     To further enhance performance of an air-conditioning system, an in-line refrigerant filter may be employed to remove impurities from the refrigerant flow. The in-line filter is typically separately installed on the low pressure side of the system between the compressor and the evaporator. The installation of the filter requires a pair of brazed joints at opposed ends of the filter in order to secure the filter into the refrigeration lines of the system. In addition, the in-line filter can also include a desiccant to remove moisture from the refrigerant flow. Some examples of accumulators and/or filter arrangements can be found in U.S. Pat. Nos. 5,575,833 and 5,562,427 that are directed to an accumulator provided with a desiccant, and an accumulator housed within a compressor that is provided with a desiccant, respectively. 
     While systems formerly using refrigerants such as R-22 typically did not require inclusion of a desiccant filter to operate at near peak performance levels, systems using newer refrigerants such as R-410a often require the desiccant filter for proper operation of the system. Therefore, existing systems that are incorporating these newer, more environmentally friendly refrigerants will require the installation of a separate in-line desiccant filter for optimum performance. Further, it is common in the HVAC&amp;R industry to replace any desiccant in the system at the same time as the compressor is replaced, which replacement process requires the installer to unbraze and braze four separate connections in the refrigerant line, two at the compressor and two at the drier. 
     Therefore, what is needed is an accumulator with a filter and desiccant that is integral with the compressor assembly that can simplify the replacement process and work efficiently with newer refrigerants. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a compression device for use in a HVAC&amp;R system having a refrigerant flowing through the system. The compression device includes a compressor to compress refrigerant vapor having a compressor shell. The compressor has a compressor inlet to receive refrigerant vapor and a compressor outlet to transmit compressed refrigerant vapor from the compressor. An accumulator removes liquid refrigerant from the refrigerant flow and provides refrigerant vapor to the compressor. The accumulator has an accumulator inlet to receive refrigerant and an accumulator outlet in fluid communication with the compressor inlet to transmit refrigerant vapor to the compressor. The accumulator has a shell that is integral with the compressor shell to form a single casing assembly for the compression device. A desiccant is disposed inside the accumulator between the accumulator inlet and outlet for removing moisture from the refrigerant. 
     One advantage of the present invention is that it simplifies the installation process of a compressor and desiccant by eliminating the need for two brazed joints in the system. 
     A further advantage of the present invention is that by combining an accumulator with a desiccant, an inventory parts reduction may be realized in that a casing for the filter and/or desiccant is not required. 
     A still further advantage of the present invention is that the integrally combined compressor and accumulator/desiccant provide the advantages of space savings and moisture removal from the refrigerant without the cost associated with a system which employs a desiccant external to the compressor assembly. 
     Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic view of a prior art air-conditioning system. 
     FIG. 2 is a schematic view of a HVAC&amp;R system of the present invention. 
     FIG. 3 is a schematic view of another embodiment of the HVAC&amp;R system of the present invention. 
    
    
     Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 depicts a conventional air-conditioning system  10 . A compressor  12  is connected to a power source (not shown) and compresses refrigerant vapor when energized by the power source. The substantially compressed fluid (compressed refrigerant vapor) is transferred or transmitted via a conduit  14 , typically tubing, from compressor  12  to a condenser  16 . In the condenser  16  the substantially compressed fluid enters into a heat exchange relationship with another fluid and at least partially undergoes a phase change to a high pressure liquid. The change of the fluid to a liquid is an exothermic transformation or event, causing the vaporous fluid to give up heat to the other fluid. The fluid is then transferred or transmitted from condenser  16  via conduit  14  to an expansion device  18 . Expansion device  18  may include a valve or series of valves which causes the fluid to expand, resulting in the lowering of the pressure and temperature of the fluid. The fluid exits expansion device  18  via conduit  14  primarily as a cool low-pressure liquid, with possibly some vaporous fluid, and is transported to an evaporator  20 . In evaporator  20 , the substantially cool low-pressure liquid enters into a heat-exchange relation with yet another fluid and undergoes a phase change to be converted to substantially a gas. This phase change of the fluid from a liquid to a gas is an endothermic transformation which absorbs heat from the other fluid in contact with evaporator  20 . The volume of fluid entering into contact with evaporator  20  is enhanced or increased by use of other devices such a blower (not shown). The gas exiting evaporator  20  may include some liquid that was not converted in evaporator  20 . The fluid is then transferred via conduit  14  to a filtering device  22  that preferably employs a desiccant (not shown) to remove any water that may be present in the fluid. The refrigerant vapor, which may include liquid, from filtering device  22  is transported via conduit  14  to an accumulator  24 . In accumulator  24 , any liquid that is present in the refrigerant is removed and the liquid is stored until it vaporizes and is re-circulated back into the air-conditioning system  10 . After the liquid is removed, the refrigerant vapor is drawn into the compressor to be compressed, and the cycle is repeated. The filter  22  is typically a separate unit, requiring installation within the air-conditioning system  10  by brazing inlet and outlet connections  34 ,  36 . 
     In contrast, the present invention as illustrated in FIG. 2 incorporates a compressor  100  and an accumulator  102  into a HVAC&amp;R system similar to the AC system  10  shown in FIG.  1 . Compressor  100  is preferably a rotary or swing link compressor, however, any compressor that requires an accumulator and/or a desiccant can be used. Accumulator  102  is integrally connected or attached to the shell or casing of compressor  100 . A conduit  104  extends inside of accumulator  102  and is installed between accumulator outlet  32  and compressor inlet  26 , thereby providing a pre-installed connection between accumulator outlet  32  and compressor inlet  26 . Although not shown, accumulator  102  and compressor  100  are connected or attached by a mechanical fastening means or device, including straps, bolts, screws, brackets, adhesives, welds or any conventional method of securing components together. 
     Accumulator  102  preferably employs a screen  38  and a baffle  40 , each preferably adjacent accumulator inlet  30 , to prevent particulate matter and liquid refrigerant from entering accumulator outlet  32  and traveling to compressor  100 . A desiccant material  42  is placed between accumulator inlet  30  and screen  38  to remove any water that may be present in the refrigerant entering accumulator  102 . Any accumulator configuration that can incorporate desiccant can be used. Any suitable desiccant material that is compatible with the refrigerant of the system can be used. By incorporating desiccant  42  and screen  38  within accumulator  102 , there is no need for a separate filter, such as filter  22  from FIG. 1, thereby reducing the number of system components. Similarly, the number of brazed joints required to incorporate integrally connected compressor  100  and accumulator  102  is reduced to two, to compressor outlet  28  and accumulator inlet  30 , since the brazed connections for filter inlet and outlet  34 ,  36  are no longer required. 
     Referring to FIG. 3, an alternate embodiment of the present invention is illustrated wherein conduit  104  is contained entirely within accumulator  202 . In this construction, accumulator outlet  32  is integral with compressor inlet  26 , thereby providing conduit  104  further protection from damage using the accumulator housing. 
     While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.