Abstract:
An accumulator with an inlet port comprising a deflector for use in an air conditioning or refrigeration system, and a method for use thereof are disclosed. In operation, the accumulator is provided between the evaporator and compressor of an air conditioning or refrigeration system. Vaporized refrigerant is conveyed from the evaporator into the accumulator through an inlet port having a deflector. The deflector deflects the refrigerant from the inlet port in a spray pattern to reduce the velocity of the refrigerant thereby avoiding turbulence in the accumulator. In another embodiment, a vapor conduit inside the accumulator for conveying refrigerant to an outlet port has an open vapor inlet end with chamfered cut edges pointing away from the inlet port to avoid liquid from splashing into the vapor conduit.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    This invention relates to an accumulator for use in an air conditioning or refrigeration system and to a method for use thereof. In particular, this invention relates to an accumulator with an inlet port having a deflector. The accumulator of the present invention may be used with a variety of refrigerants including r134a and carbon dioxide, despite the higher operating pressures inherent in a system using carbon dioxide as the refrigerant.  
           [0002]    A basic refrigeration or air conditioning system has a compressor, a condenser, an expansion device, and an evaporator. These components are generally serially connected via conduit or piping and are well known in the art. During operation of the system, the compressor acts on relatively cool gaseous refrigerant to raise the temperature and pressure of the refrigerant. From the compressor, the high temperature, high pressure gaseous refrigerant flows into the condenser where it is cooled and exits the condenser as a high pressure liquid refrigerant. The high pressure liquid refrigerant then flows to an expansion device, which controls the amount of refrigerant entering into the evaporator. The expansion device lowers the pressure of the liquid refrigerant before allowing the refrigerant to flow into the evaporator. In the evaporator, the low pressure, low temperature refrigerant absorbs heat from the surrounding area and exits the evaporator as a saturated vapor having essentially the same pressure as when it entered the evaporator. The suction of the compressor then draws the gaseous refrigerant back to the compressor where the cycle begins again.  
           [0003]    In a typical air conditioning or refrigeration system, it is necessary to prevent liquid from passing from the evaporator into the compressor in order to avoid damage to the compressor. When liquid refrigerant enters a compressor, it is known as slugging. Slugging reduces the overall efficiency of the compressor and can also damage the compressor. It is well known in the art to mount a suction line or low pressure side accumulator between the evaporator and compressor. Such suction line accumulators act to separate the liquid and gaseous phases of the refrigerant flowing from the evaporator. The refrigerant from the evaporator enters the accumulator through an inlet port at a relatively high velocity. The liquid phase of the refrigerant will settle to the bottom of the accumulator while the gaseous phase will rise to the top of the accumulator and will be suctioned out of the accumulator by the compressor.  
           [0004]    In order to achieve sufficient separation of the gaseous and liquid phases of the refrigerant, it is necessary to reduce the turbulence of the liquid in the accumulator. Several systems and methods have been employed in the past in an effort to reduce the turbulence in accumulators. For example, U.S. Pat. No. 3,609,990 to Bottum discloses bending the lower portion of the inlet port slightly towards the interior wall of the accumulator so that the liquid and gas flows out of the inlet tube at a downward angle in a direction tangential to the accumulator wall. U.S. Pat. Nos. 3,643,466, 3,837,177, and 5,167,128 all to Bottum disclose an inlet port with a portion of one wall deformed inwardly into the port to form a scoop for directing the flow of liquid and gaseous refrigerant entering the accumulator toward the interior wall of the accumulator. U.S. Pat. No. 5,660,058 discloses the use of a domed shaped deflector below the inlet port to effectively separate the liquid and gaseous phases of the refrigerant and reduce turbulence.  
           [0005]    While the above accumulators are suitable for their intended purpose, it is believed that there is a demand in the industry for an accumulator with an improved inlet port, which can separate the liquid, and gaseous phases of the refrigerant entering the accumulator while at the same time reduce turbulence. It is further believed that there is a demand for an accumulator with an improved inlet port which is less costly to manufacture, but yet provides a high level of efficiency.  
         BRIEF SUMMARY OF THE INVENTION  
         [0006]    In a preferred embodiment, an inlet port for an air conditioning or refrigeration system accumulator comprises a conduit for conveying refrigerant, the conduit having an upper end and a lower end, and a deflector formed at the lower end of the conduit, the deflector having a planar deflecting surface.  
           [0007]    In another embodiment, an accumulator for an air conditioning or refrigeration system comprises a housing having a chamber formed by a sidewall, a bottom wall, and a cover, an inlet port for conveying refrigerant, the inlet port comprising a deflector, wherein refrigerant flowing through the inlet port strikes the deflector and is deflected in an arc, an outlet port, and a vapor conduit having a vapor inlet positioned inside the chamber for conveying refrigerant in the accumulator to the outlet port.  
           [0008]    In another aspect, an accumulator for an air conditioning or refrigeration system comprises a housing having a chamber formed by a sidewall, a bottom wall, and a cover, an inlet port for conveying refrigerant, an outlet port for discharging refrigerant from the accumulator, and a vapor conduit inside the chamber for conveying refrigerant in the accumulator to the outlet port, the conduit having a vapor inlet with chamfered edges pointing away from the inlet port.  
           [0009]    In yet another aspect, a method of operating an air conditioning or refrigeration system is provided. First, the refrigerant is conveyed from a compressor to a condenser. Next, the refrigerant is conveyed from the condenser to an expansion device. Then, the refrigerant is conveyed from the expansion device to an evaporator. Next, the refrigerant is conveyed from the evaporator to an inlet port of an accumulator. Then, the refrigerant conveyed through the inlet port is deflected into an arc into the accumulator. Next, the refrigerant in the accumulator is conveyed through a vapor conduit inside the accumulator to an outlet port. Finally, the refrigerant is discharged through the outlet port to the compressor.  
           [0010]    The present invention provides significant advantages over the prior art by providing cost-efficient systems and methods to further reduce turbulence of liquid inside an accumulator.  
           [0011]    Further features and advantages of the present invention will be apparent upon reviewing the following detailed description and accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS  
       [0012]    [0012]FIG. 1 is a schematic of one embodiment of an air conditioning system using an accumulator of the present invention.  
         [0013]    [0013]FIG. 2 is a front cut-away view of one embodiment of the accumulator of the present invention having an inlet port deflector.  
         [0014]    [0014]FIG. 3 is a top cut-away view of the embodiment shown in FIG. 2.  
         [0015]    [0015]FIG. 4 is a close-up perspective view of one embodiment of an inlet port deflector.  
         [0016]    FIGS.  5 A-D shows a perspective view of one embodiment of the various stages of an inlet port deflector as it is manufactured.  
         [0017]    [0017]FIG. 6 is a flow chart of one embodiment of a method of operating an air conditioning or refrigeration system using an accumulator of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0018]    [0018]FIG. 1 is a schematic of an air conditioning system incorporating the accumulator and inlet port of the present invention. In general, high pressure, high temperature refrigerant exits a compressor  1  and flows into a condenser  3 . The high temperature liquid refrigerant exits the condenser and flows into an expansion device  5  and subsequently into an evaporator  7 . Low pressure refrigerant exits the evaporator  7  and enters the accumulator  9  where the liquid and gaseous phases of the refrigerant are separated. Gaseous refrigerant is then suctioned out of the accumulator  9  and flows back to the compressor  1 . It also should be understood that the accumulator of the present invention may contain an internal heat exchanger and be incorporated into both the high pressure and low pressure sides of the system. A detailed discussion of such an accumulator is provided in U.S. patent application Ser. No. 09/752,419, filed Dec. 29, 2000, which is hereby incorporated by reference.  
         [0019]    As illustrated in FIG. 2, the accumulator  10  includes a housing  14 , with sidewalls  18 , a bottom wall  22 , and a cover  24 , forming a chamber  26 . The sidewalls  18  and the bottom wall  22  are preferably integrally formed to form the lower portion of the accumulator  10 . The cover  24  is separately formed from the housing and forms the upper portion of the accumulator  10 . While the accumulator shown in the figures is cylindrical in shape, the accumulator of the present invention may have any shape, including square, rectangular or ellipsoidal. The accumulator is preferably stainless steel, but also may be aluminum, copper, or any other suitable material.  
         [0020]    The cover  24  has two openings  28  and  32  for receiving a low pressure inlet port  36  and a low pressure outlet port  40  respectively. The inlet port  36  has an upper end  33  and a lower end  35 . The openings  28  and  32  may be circular, elliptical, square, rectangular, or any other desired shape. The low pressure inlet port  36  and low pressure outlet port  40  generally correspond in shape to the openings  28  and  32  in the top of the cover  24 . In a preferred embodiment, the openings  28  and  32  are circular, and the low pressure inlet port  36  and low pressure outlet port  40  are cylindrical in shape. The low pressure inlet port  36  and low pressure outlet port  40  may be formed from aluminum, stainless steel, copper, or any other suitable material. Preferably, the inlet and outlet ports are formed from stainless steel.  
         [0021]    A vapor conduit  44  with a vapor inlet end  48  and a vapor outlet end  52  is positioned inside the housing  14 . The vapor outlet end  52  is connected to the low pressure outlet port  40 . The vapor outlet end  52  may be affixed to the low pressure outlet port  40  by soldering, brazing, welding, or any other suitable method known in the art. In other embodiments, the vapor outlet end  52  and the low pressure outlet port  40  may comprise one piece. Preferably, the vapor conduit  44  is a stainless steel cylindrical J-shaped tube or J-tube. However, the vapor conduit  44  may have any other desirable shape, including linear, and may be formed from any suitable material such as aluminum or copper. The vapor conduit  44  extends vertically from the vapor outlet end  52  into the lower portion of the housing  14  adjacent the bottom wall  22 , and is curved at its lower-most point  56 . The J-shaped vapor conduit  44  extends upwardly from the lower most point  56  to the vapor inlet end  48 .  
         [0022]    The J-shaped vapor conduit  44  has one or more openings  60  in the curved portion of the tube, which allows liquid refrigerant accumulated in if the bottom of the accumulator to be drawn through the opening  60  into the J-shaped vapor conduit  44 , and out of the accumulator through the vapor outlet end  52  connected to the low pressure outlet port  40 . In alternative embodiments, oil from a sump  90  at the bottom of the housing  14  may be drawn into the J-shaped vapor conduit through the opening  60  where the oil mixes with the gaseous refrigerant flowing through the tube and out of the low pressure outlet port  40 .  
         [0023]    As shown in FIGS. 2 and 4, the low pressure inlet port  36  has a deflector  64 . A sidewall  63  and a deflecting surface  65  form the generally L-shaped deflector  64 . The inlet port deflector  64 , of which a close-up view is shown in FIG. 4, is formed at the lower end  35  of the inlet port  36  and extends away from the generally vertical inlet port  36  towards the sidewall  18 . The inlet port deflector  64  may have a deflection angle θ, shown in FIG. 5D ranging from 45 to 90 degrees from the bottom of the port. In a preferred embodiment, the inlet port deflector  64  has a deflection angle of about 75 degrees. The deflecting surface  65  is preferably shaped in the form of a rectangle or square, but may be other shapes such as circular, elliptical, or any other suitable shape. The inlet port deflector  64  may be formed integrally from the inlet port or may be separately formed and affixed to the lower end  35  of the inlet port by soldering, brazing, welding, or any other suitable method. In a preferred embodiment, the inlet port  36  and the deflector  64  are integrally formed.  
         [0024]    If the deflector  64  is formed separately from the inlet port, the deflector may be aluminum, stainless steel, copper, or any other suitable material. Preferably, a deflector  64 , which is formed separately from the inlet port, is the same material as the inlet port. In a preferred embodiment the inlet port  36  and the deflector  64  are stainless steel.  
         [0025]    FIGS.  5 A-D show one method of forming an inlet port deflector. First, an inlet port  36  is provided. The inlet port is preferably cylindrical, but may be other shapes. Next, a notched step  68  is formed into the inlet port  36 . The notched step may be machined or cut. Then, the notched step  68  is flattened as shown at  72 . Finally, the flattened notched step is bent to form the deflector  64  with the correct profile angle θ as shown at  76 .  
         [0026]    In operation, low pressure, low temperature refrigerant flowing from the evaporator at a relatively high velocity enters the accumulator  10  through the inlet port  36 . The refrigerant strikes the deflecting surface  65  and flows off of the deflector toward the sidewall  18  of the accumulator and away from the vapor inlet  48  in an arc or fan-shaped pattern  78  as shown in FIG. 3. In one embodiment, the arc through which the refrigerant is sprayed is from about 45 to 180 degrees. In a preferred embodiment, the arc is 180 degrees.  
         [0027]    The deflector slows down the velocity of the refrigerant entering the accumulator while directing the refrigerant flow down the sidewall  18  of the accumulator housing  14 . Any liquid refrigerant flows down the sidewall  18  in a laminar fashion while the gaseous refrigerant rises to the upper portion of the accumulator and flows into the vapor inlet  48  of the J-tube. As a result, the incoming refrigerant is not directed at a high velocity against any standing liquid refrigerant, which may be retained in the lower portion of the housing  14 . Undesired turbulence of the standing liquid is therefore minimized which further prevents liquid refrigerant from entering the vapor inlet  48 .  
         [0028]    The vapor, which flows into the J-tube, passes downwardly through the vapor conduit  44  reaching its lower-most point  56 . The suction of the gas allows the liquid refrigerant and oil mixture accumulated in the bottom of the accumulator to be drawn through the opening  60  into the J-shaped vapor conduit  44 , where it is then sucked upwardly along the J-shaped ha vapor conduit  44  and out of the accumulator through the vapor outlet end  52  connected to the low pressure outlet port  40 . It is to be understood that the liquid refrigerant and oil mixture, which is metered into the vapor conduit  44  through the opening  60 , is entrained in the stream of gaseous refrigerant. It remains entrained in the gas as it passes from the accumulator and is drawn to the compressor of the system. The opening  60  allows the liquid refrigerant to be metered into the compressor at a controlled rate, thereby avoiding large amounts of liquid refrigerant from entering and damaging the compressor.  
         [0029]    The present invention has system efficiency, cost, and complexity improvements over the prior art. The design limits the turbulence of the refrigerant in the accumulator. Further, the deflector may be integral to the inlet port, which reduces part and manufacturing costs as well as the complexity of the accumulator. Additionally, the present invention allows the liquid storage capacity of the accumulator to be increased by allowing the inlet of the vapor conduit to be near the top of the accumulator.  
         [0030]    In another embodiment, as shown in FIG. 3, the vapor inlet end  48  of the vapor conduit  44  is trimmed with an angled or chamfered cut  80 , with the opening pointing directly away from the inlet port  36 . This, on one hand, serves to block liquid particles from entering the vapor inlet end  48  of the vapor conduit  44 , and on the other hand, increases the flow area and reduces the pressure drop in the vapor conduit  44 . It also serves to prevent restriction if the vapor conduit  44  is bottomed against the inside top of the accumulator  10 . Similarly, the chamfered cut is desirable for functioning because the vapor conduit  44  can be positioned higher in the housing  14  to allow for greater liquid storage capacity within the accumulator  10 . It is recognized that the chamfered cut  80  may be utilized independently of the inlet port deflector  64 , or in combination thereof.  
         [0031]    A method of operating an air conditioning or refrigeration system is shown in the flowchart in FIG. 6. First, refrigerant is conveyed from a compressor into a condenser. Refrigerant from the condenser is then conveyed to an expansion device. The refrigerant is then conveyed from the expansion device to an evaporator. Refrigerant from the evaporator is conveyed to an inlet port of an accumulator. The accumulator further comprises a housing forming a chamber, an outlet port, and a vapor conduit inside the chamber. Refrigerant conveyed through the inlet port is deflected into an arc such that any liquid refrigerant flows down the sides of the housing, and any gaseous refrigerant flows into a vapor conduit. Finally, the refrigerant in the vapor conduit is discharged through an outlet port and flows back to the compressor.  
         [0032]    While the invention with its several embodiments has been described in detail, it should be understood that various modifications may be made to the present invention without departing from the scope of the invention. The following claims, including all equivalents define the scope of the invention.