Abstract:
A single bracket serves to both attach a TXV bulb to an outer surface of an outlet header and to place a securely hold the distribution assembly in a fixed position with respect to the TXV bulb. A pair of clam shell clamping members on opposite ends of a central member are put in position and clamped to hold the TXV bulb tightly in place against the outlet header and to clamp around the equalizer of the distributor assembly, thereby resulting in a rigid interconnection which maintains the desired positions for each of the components.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This invention relates generally to refrigeration systems and, more particularly, to a method and apparatus for mounting a distributor and thermal expansion valve assembly in a refrigeration system. 
         [0002]    In air conditioning and refrigeration systems it is common to maintain a certain degree of superheat in the refrigerant passing from the evaporator to the compressor in order to protect the compressor from damage that can occur by liquid refrigerant passing therethrough. This is accomplished by using a thermal expansion valve (TXV) upstream of the evaporator coil, with an associated temperature sensor or bulb for sensing the temperature of the refrigerant passing from the evaporator coil. 
         [0003]    In one type of air conditioner that is used in combination with a furnace, an A-coil is provided with a piping assembly which includes the thermal expansion valve being attached to the liquid line and, in close proximity, the sensor bulb being attached to the outlet header. 
         [0004]    In order for the bulb to provide accurate temperature readings, it is necessary to mount the bulb in such a way as to ensure a fixed and firm engagement with the header and to isolate the bulb from the surroundings. The first function had generally been served by one or more clamps and the second function has generally been accomplished by providing some kind of protective cover over the area in which the bulb is secured to the outlet line. The most common type of insulation that is provided around the bulb of an A-coil is a foam tape that is wrapped around the clamp. The problems with this approach are twofold. First, it is difficult to access that portion of the piping assembly and to obtain a firm and proper securing of the clamp and bulb to the outlet header. Secondly, the wrapping of the insulation tape will vary greatly with the serviceman applying it and may well not be sufficient to ensure good isolation of the bulb that would result in accurate readings. 
         [0005]    Other types of temperature sensors are also used to sense refrigerant temperatures in various lines of a refrigeration system for purposes of control and/or protection of the system. These sensors are subject to the same problems as discussed hereinabove. 
         [0006]    Another problem that occurs with A-coil piping assemblies is that of the distributor assembly, which includes both the TXV and the liquid line leading to it, vibrating in shipping or operational use and eventually causing failure of the liquid line. This problem is presently addressed by a separate clamp that rigidly interconnects the liquid line to the outlet header. 
       SUMMARY OF THE INVENTION 
       [0007]    Briefly, in accordance with one aspect of the invention, a pre-formed and insulated bracket is wrapped around the bulb so as to securely attach it to the outlet line and provide an insulating cover thereover. 
         [0008]    By another aspect of the invention, the bracket also extends around the liquid line to secure the distributor assembly in its correct relationship to the outlet header. 
         [0009]    In the drawings as hereinafter described, a preferred embodiment is depicted; however, various other modifications and alternate constructions can be made thereto without departing from the spirit and scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a perspective view of a piping assembly for an A-coil in accordance with the prior art. 
           [0011]      FIG. 2  is a perspective view of the bracket in accordance with the present invention. 
           [0012]      FIG. 3  is a front side view thereof. 
           [0013]      FIG. 4  is an end view thereof. 
           [0014]      FIG. 5  is a sectional view thereof as seen along lines  5 - 5  of  FIG. 3 . 
           [0015]      FIG. 6  is a sectional view thereof as seen along lines  6 - 6  of  FIG. 3 . 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0016]    Referring to  FIG. 1 , there is shown an A-coil assembly comprising a pair of evaporator coils  12  and  13  attached at their upper ends  14  to form an A-shape in a well known manner. An end plate  16  is installed in each end of the A-coil. 
         [0017]    An A-coil assembly is commonly used in a furnace to provide an air conditioning mode of operation, with the furnace blower acting to receive return air from a building and pass it through the A-coil to be cooled prior to flowing out of the duct to cool the building. The present invention is related to the refrigeration circuit that is associated with the A-coil assembly  11 . 
         [0018]    In a line coming from the condenser, which is located in the outdoor coil, the refrigerant flows to the distributor assembly  17 . The distributor assembly includes a liquid line  18 , a thermal expansion valve (TXV)  19  with an equalizer line  20  and a plurality of capillary tubes  21  which carry the distributed refrigerant vapor to the various circuits in the coils  12  and  13 . The TXV operates to selectively control the degree of expansion of the refrigerant into the capillary tubes  21 . 
         [0019]    On the downstream side of the unit, the refrigerant vapor, after having been heated by heat exchange relationship with air passing through the coils  12  and  13 , passes through the plurality of tubes  22  to an outlet header  23 , from where it then flows to the compressor, after which the compressed vapor then passes to the condenser to complete the refrigerant cycle. 
         [0020]    In order to ensure that all of the refrigerant passing to the compressor is in the vapor form (i.e. to prevent liquid refrigerant from passing to the compressor and causing damage), it is desirable to maintain the refrigerant passing from the header  23  in a superheated condition. This is accomplished by controlling the TXV in order to maintain a constant superheat at the coil outlet regardless of load conditions. That is, the size oldie variable orifice in the TXV  19  is determined by a temperature sensor or a TXV bulb  24  which is attached to the outlet header  23  in such a way as to sense the temperature of the refrigerant passing through the header  23  and to activate the TXV in response thereto. 
         [0021]    In order to ensure that the TXV bulb is held tightly and consistently against the wall of the outlet header  23 , so as to provide an accurate sensing of the refrigerant temperature, a hose clamp  26  has generally been used as shown. 
         [0022]    In addition to the hose clamp  26 , it has been found necessary to insulate the TXV bulb by isolating it from the surrounding area. This has generally been done by wrapping foam tape around the hose clamp  26 . 
         [0023]    The applicants, have recognized that both the installation, of the hose clamp  26  and the insulated tape can vary substantially between one assembly person and another, and may well result in an improper installation, which will cause improper readings of the TXV bulb and improper operation of the TXV. 
         [0024]    It is desirable to place the distributor assembly  17  near that portion of the outlet header  23  or which the TXV bulb is attached. Further, it is desirable to provide structural support for the distributor assembly since shipping and. Or operational vibrations are likely to cause a failure in unsupported portions thereof such as at the equalizer line  20 . These functions have been accomplished in the past by a separate bracket  27  that wraps around both the outlet header  23  and the liquid line  18  to both position the distributor assembly  17  and prevent the vibrations that would otherwise occur. 
         [0025]    The present invention is intended to serve the purposes of the hose clamp  26 , the insulation wrap, and the bracket  27 . 
         [0026]    Referring now to  FIGS. 2-6 , the bracket of the present invention is shown at  28  with a primary or first clamp member attached to its one end and a secondary or second clamp member  32  attached at its other end thereof. 
         [0027]    As will be best seen in  FIG. 5 , the first clamp member  31  has a base arcuate member  33  and a distal arcuate member  34  interconnected in an integral manner at an intermediate point  36 . The base arcuate member  33  is integrally connected to the elongate central member  29  at connection point  37 . It should be understood, however, that the base arcuate member  33  may be a separate unit rather than integral with the central member  29  as shown and may be connected by other means such as by a fastener or the like. In this regard, it is necessary that the first clamp member  31  be hinged or flexible to the degree which would allow it to be opened from its relationship with the central member  29  to allow it to be installed in a manner to be described hereinafter. 
         [0028]    At the one end of the central member  29  there is an integrally connected cradle portion  38  which is arcuate in form with a leg extending upwardly to a point  39 . On an outer side of the cradle member  38 , near the end  39 , are a plurality of generally downwardly extending teeth  41 . In a related manner, the distal arcuate member  34  extends downwardly to an end  42  and has generally upwardly extending teeth  43  that are adapted to engage the teeth  41  when the first clamp member  31  is in a closed position. 
         [0029]    Disposed within the base arcuate member  33  is a liner  44  which is generally coaxial with the base arcuate member  33  and serves to hold the bulb in place (i.e. to prevent it from coming out of the front or back of the charge). Located on the inner diameter of the liner  44  is a sheet of insulation  46  that closely adheres to the inner diameter of the liner  44  and acts to insulate the TXV bulb from outside temperatures in a manner to be described hereinafter. 
         [0030]    The insulation  46  may be a separate element as shown that is either attached to the liner  44  or as a separate piece that is set in to the position against the inner diameter of the liner  44 . Alternatively, the insulation may be integrated into the base arcuate member  33  as, for example, by being integrated into the material of the liner  33 . A typical material that would be used in the embodiment as shown for the insulation  46  is a closed cell foam or any suitable insulating material. 
         [0031]    Referring, now to the second clamp member  32  at the other end of the central member  29 , the clamp member  32  is arcuate in form, extending downwardly and around a bottom portion of a cavity  47  and then upwardly on the other side to a termination point  48 . On the other side is a downwardly extending U-shaped portion  49  into which the termination point  48  extends. Again, the second clamp member  32  is composed of a material which is flexible to allow the clamp to be opened by withdrawing the termination point  48  downwardly to the extent that the equalizer line  18  can be inserted into the cavity  47 , after which, the termination point is inserted back into the U-shaped portion  49  and locked in place. This can be accomplished by engaging a hook on the outer portion of the U-shaped member  49  until, it engages an edge of the outer side of the termination point  48  as shown in  FIG. 6 . 
         [0032]    Considering now the manner in which the bracket  28  is installed in an A-coil assembly, and the outlet header  23  and the liquid line  18 , in particular, the respective teeth  41  and  42  are disengaged and the first clamp member is opened to the degree which will allow the base arcuate member  33  to be placed over the TXV bulb  24  as shown in  FIG. 5 . The cradle member  38  is then brought up under the outlet header  23  such that the surface of the TXV bulb  24  engages the outer surface of the outlet header  23  as shown. The first clamp member  31  is then brought to the closed position such that the base, arcuate member  33  is tightly held against the outer surface of the TXV bulb  24  and the bulb closely engages the outer surface of the outlet header  23 . In turn, the distal arcuate member  34  wraps around the outer surface of the outlet header  23  and the respective teeth  41  and  42  are engaged to hold the first clamp member  31  in a closed position. 
         [0033]    In a subsequent, step or in an initial step of one prefers, the second clamp member  32  is moved to the open position, and placed over the liquid line  18  as shown in  FIG. 6  and then moved to the closed position. The result is a rigid attachment between the outlet header  23  and the liquid line  18  such that the distributor assembly  17  is held in its place with respect to the TXV bulb and prevented from vibrating during shipping or when the system is operating. At the same time, the TXV bulb is securely held in place and in a precise and consistent manner so as to provide accurate readings for control of the TXV. 
         [0034]    The bracket  28  is preferably a unitary member as shown but may well be of multiple interconnected members. The material with which it is made is preferably a flexible plastic material such as nylon. However, it is understood that various other materials can as well be used in accordance with the present invention.