Abstract:
An annular isolator is provided having a metal tube which acts as a spring while defining a flow path and a resilient member located between two loading plates. The resilient member supports the weight of one of the members being coupled and the tube acts as spring as to transmitting vibration.

Description:
BACKGROUND OF THE INVENTION 
     Rigid connections between structural members in a mechanical system can be a path of vibrational propagation between members. One arrangement in which this can occur is in a refrigeration system chiller where a compressor is mounted on a heat exchanger through a rigid connection that serves as a fluid path between the members. 
     Screw compressors, especially high, speed geared compressors, generate high levels of structure borne energy in a frequency range where components of the systems in which they are typically applied are very responsive. This often leads to unacceptably high radiated sound levels from both the compressor and the rigidly attached system components. The problem is particularly acute with compressors designed to be directly mounted on a heat exchanger shell such that the compressor is fully supported by a flange extending directly from the shell. This is because this joint tends to transmit energy very efficiently from the compressor to the heat exchanger shell. Reducing this transmission by conventional means such as elastomeric or helical springs is very difficult due to the conflicting requirements placed on the joint. Specifically, the joint must hermetically contain the refrigerant, withstand the operating pressure in the system, and be structurally robust, especially if the joint represents the sole support for the compressor. Additionally, space requirements are often very restrictive since minimizing package size is critical. 
     SUMMARY OF THE INVENTION 
     The present invention is essentially a stand alone insertion installed between two flanges and providing a fluid path. A flexible metal tube acts as a spring to isolate vibration while defining a portion of the fluid path thereby fully containing the refrigerant. Hence, the present invention can be incorporated without requiring any major design changes. A piece of elastomer such as rubber or neoprene is located radially outward of the metal tube and between a pair of metal loading plates. The two plates are used to hold together the flanges of the members being coupled while the elastomer is compressed due to its supporting the weight of one of the members, the compressor. 
     It is an object of this invention to reduce heat exchanger vibration due to compressor excitation in a refrigeration or air conditioning system. 
     It is another object of this invention to reduce structure borne sound resulting from compressor operation 
     It is an additional object of this invention to reduce overall sound radiation from a chiller. 
     It is a further object of this invention to provide an axially compact vibration isolator. These objects, and others as will become apparent hereinafter, are accomplished by the present invention. 
     Basically, an annular isolator is provided having a metal tube or conduit which acts as a spring while defining a flow path and a resilient member located between two loading plates which supports the weight of one of the members being coupled and the metal tube or conduit acts as a spring as to transmitting vibration. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a fuller understanding of the present invention, reference should now be made to the following detailed description thereof taken in conjunction with the accompanying drawings wherein: 
     FIG. 1 is a sectional view of the present invention providing vibration isolation and a fluid connection between a compressor and a heat exchanger; and 
     FIG. 2 is a partial sectional view of a modified embodiment of the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In FIGS. 1 and 2 the numeral  10  generally designates a refrigerant compressor, such as a screw compressor, and the numeral  12  designates a heat exchanger such as a cooler or evaporator of a refrigeration or air conditioning system. Compressor  10  has an annular groove  10 - 1  which receives o-ring  11 . Cooler  12  has a flange  12 - 1  with an annular groove  12 - 2  which receives o-ring  13 . 
     Referring specifically to FIG. 1, compressor  10  engages and is supported by annular metal ring  20  which overlies elastomeric member  30 . Annular member  30  may be made up of two semicircular members or a single member with a radial slit to permit manipulation for installation. Elastomeric member  30  overlies annular metal ring  40  which, in turn, overlies flange  12 - 1 . Corrugated tube  80  is located within and surrounded by members  20 ,  30  and  40 . Tube  80  is welded or otherwise suitably secured to members  20  and  40  in a fluid tight manner. Alternatively, tube  80  can be formed integral with member  20  and/or  40 . Also, member  20  can be made integral with compressor  10  and/or member  40  can be made integral with flange  12 - 1 , which would eliminate the need for o-ring  11  and/or  13  and the grooves to receive them. Members  20  and  40  and flange  12 - 1  have a plurality of circumferentially spaced bores  20 - 1 ,  40 - 1  and  12 - 3 , respectively, having clastomeric sleeves  22 ,  23  and  24 , respectively, located therein. Annular steel plate  60  is massive in the sense that it will not deflect when bolted in place and in that it provides a large surface area for contacting elastomeric member  50 . Annular member  50  is made of an elastomeric material such as rubber or neoprene and may be made up of two, or more, partial circular members or a single member with a radial slit to permit installation. 
     Circumferentially spaced bolts  70  extend serially through bores  60 - 1 ,  50 - 1 ,  24 - 1 ,  23 - 1 ,  30 - 1 ,  20 - 1  in members  60 ,  50 ,  24 ,  23 ,  30  and  20 , respectively, before being threaded into threaded bore  10 - 2  in compressor  10 . 
     Bolts  70  are tightened to the extent that members  20 ,  30 ,  40 ,  12 - 1  and  50  are squeezed into intimate contact between compressor  10  and plate  60 . Accordingly, o-ring  11  provides a fluid seal between compressor  10  and plate  20 . Similarly, o-ring  13  provides a fluid seal between cooler flange  12 - 1  and plate  40 . Tube  80  protects member  30  from exposure to refrigerant or other fluid passing between heat exchanger  12  and compressor  10 . While tube  80  is integral with members  20  and  40 , it connects members  20  and  40  in a flexible manner due to its corrugations  80 - 1  such that it acts in the nature of a spring relative to transmitting vibrations. The only other metal-to-metal contact is the heads of bolts  70  contacting plate  60  and bolts  70  being threaded into threaded bores  10 - 2  but this transmission path is interrupted by elastomeric member  30  which supports the weight of compressor  10  and elastomeric member  50  which is compressed between plate  60  and flange  12 - 1  by the threading of bolts  70  into threaded bores  10 - 2 . 
     It will be noted that the axial separation of compressor  10  and heat exchanger  12  is increased only by the thickness of members  20 ,  30  and  40  which would be on the order of 0.75 inches or 20 mm. Further, elastomeric member  30  effectively vibrationally isolates compressor  10  and heat exchanger  12  and provides extreme damping since it is supporting the weight of compressor  10  and is subject to the further compression and resulting damping due to the tightening of bolts  70 . 
     Referring now to FIG. 2, corrugated tube  80  has been replaced with an annular tubular member  180  which is put in place by virtue of an interference fit. Plate  120  corresponds to plate  20  but has a small, inwardly radially extending circumferential lip  120 - 2  and a circumferential recess  120 - 3  for receiving o-ring  121 . Plate  140  corresponds to plate  40  but has a inwardly radially extending circumferential lip  140 - 2  and a circumferential recess  140 - 3  for receiving o-ring  141 . The rest of the structure of FIG. 2 is the same as that of FIG.  1 . 
     As noted, tubular member  180  is set in place by an interference fit. Specifically, member  180  can be cooled sufficiently so that it can pass through the opening defined by lip  120 - 2  and set in place such that upon reaching ambient temperature it will be in an interference fit and in sealing engagement with o-rings  121  and  141 . Although there is metal-to-metal contact between tubular member  180  and plates  120  and  140 , tubular member  180  is capable of relative axial movement, within the constraints of lips  120 - 2  and  140 - 2 , relative to plates  120  and  140  such that, effectively, there is a resilient connection between member  180  and members  120  and  140  relative to transmitting vibrations. As in the FIG. 1 embodiment, compressor  10  can incorporate plate  120  and/or flange  12 - 1  can incorporate plate  140 . 
     Although preferred embodiments of the present invention have been specifically illustrated an described, other changes will occur to those skilled in the art. For example the description has been specific to a chiller but is applicable to other fluid connections, such as in fluid pipelines. It is therefore intended that the scope of the present invention is to be limited only by the scope of the appended claims.