Patent Publication Number: US-2022235891-A1

Title: Dual plane seal air conditioner connector

Description:
FIELD OF THE DISCLOSURE 
     This disclosure relates to connectors used in conduit systems for conveying refrigerants in air conditioning systems, and more particularly to a connector having multiple seals to reduce refrigerant leakage. 
     BACKGROUND OF THE DISCLOSURE 
     It is highly desirable to reduce leakage of refrigerants from air conditioning systems to reduce emissions of greenhouse gases into the environment, to maintain the cooling capacity and functionality of the air conditioning systems, and to reduce maintenance. Moreover, the more environmentally friendly tetrafluoropropene (R1234yf) refrigerant, which is mandated for all NAFTA vehicles by the model year 2021, has a higher flammability rating than currently used refrigerants such as tetrafluoroethane (R134a), creating an additional incentive for preventing refrigerant leakage. Further, there are incentives to reduce refrigerant emissions in order to gain government issued carbon credits. 
     Connectors used in motorized vehicle applications typically comprise male and female connector blocks that are fastened together. These connectors typically employ a single fastener to simplify assembly and reduce time and labor. Such connectors are sometimes referred to as cantilevered conduit connectors because the fastener extends through a passage at an end of the connector opposite an end of the connector wherein the conduit passage is located, resulting in a non-uniform distribution of forces between the mating surfaces of the connector blocks. The uneven distribution of forces can cause the mating surfaces of the connector blocks to develop gaps that could allow an undesirable leakage around seals. 
     SUMMARY OF THE DISCLOSURE 
     Disclosed is a dual plane seal connector designed to provide highly leak resistant engagement between tubular fluid conduits, while employing a single fastener. The connector includes a female connector block including a generally planar face having a conduit receiving passage in fluid communication with a second fluid conduit, and a male connector block having a generally planar face for abutting the generally planar face of the female connector. A counter-bored conduit passage is provided in the generally planar face of the male connector block. The counter-bored conduit passage includes a first cylindrical bore having a first diameter and a first depth and a second cylindrical bore coaxial with the first cylindrical bore. The second cylindrical bore has a second diameter greater than the first diameter and a second depth less than the first depth. A tubular fluid conduit extends through the conduit passage. A circumferential groove is defined in a portion of the tubular fluid conduit that protrudes outwardly from the conduit passage and away from the generally planar face of the male connector block and into the conduit receiving passage of the female connector block. A sealing ring is located in the groove to provide a radial seal, and a seal washer is located in the second cylindrical bore to provide an axial seal. 
     Together, these features provide a simple, inexpensive design that provides easy assembly, and reduced leakage due at least in part to the use of two independent seals, and at least in part to reduced opportunity for gaps between the mating faces of the connector blocks because the sealing washer is recessed into the face of the male connector. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side cross-sectional view of a male connector block in accordance with this disclosure. 
         FIG. 2  is an end view of the male connector block shown in  FIG. 1 . 
         FIG. 3  is a side view of a female connector block in accordance with this disclosure. 
         FIG. 4  is a top view of the seal washer providing axial sealing between the male connector block and the female connector block. 
         FIG. 5  is a cross-sectional view of the seal washer as viewed along lines A-A of  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Shown in  FIGS. 1 and 2  is a male connector block assembly  10 , including a male connector block  12  and a tubular fluid conduit  14 . Male connector block  12  has a generally planar face  16  for mating by abutting a generally planar face  18  of a female connector block  20  ( FIG. 3 ). The expression “generally planar face” means that face  16  of block  12  (and face  18  of block  20 ) are mostly (more than 50%) flat, parallel to each other, and in contact with each other when the connector is fully assembled. A counter-bored conduit passage  22  extends through male connector block  20  from face  16  to a back side  24  of block  20 . Passage  22  includes a first cylindrical bore  26  having a first diameter d 1  and a first depth D 1  (equal to the thickness of block  20 ), and a second cylindrical bore  28  having a second diameter d 2  and a second depth D 2 . In the illustrated embodiment, the depth D 2  of the second cylindrical bore  28  is such that a crimped section  30  of conduit  14  and a seal washer  32  are accommodated, with the outwardly facing surface of seal washer  32  (i.e., the surface facing to the right in  FIG. 1 ) being flush (i.e., level) with or coplanar with generally planar face  16  when it is compressed between male connector block  12  and female connector block  20 . By using a round seal washer  32  disposed in a counter base (i.e., second cylindrical bore  28 ) on the generally planar face  16  of male connector block  12 , as opposed to using a washer that is disposed between the entire area of generally planar faces  16  and  18  of blocks  12  and  20 , cantilever (i.e., the tendency of the faces  16  and  18  to become skewed or non-parallel when fastened together) is reduced. 
     Optionally, a protuberance  34  can be provided on the generally planar face  16  of male connector block  12  to further reduce cantilever when male connector block  12  and female connector block  20  are fastened together. While protuberance  34  can be developed by machining the entire face  16  of block  12 , protuberance  34  is preferably created by stamping or coining the face  16  adjacent to a fastener passage  36  to raise a predetermined amount of material to project away from face  16  (i.e., to the right in  FIG. 1 ). The protuberance  34  can have a tapered shape that thins to a point in the outward direction (i.e., toward the right in  FIG. 1 ). During assembly of the connection, the protuberance will create an anti-cantilever effect. The torque load caused by fastening blocks  12  and  20  together, such as with a nut tightened or torqued onto a threaded stud  42  that projects from the substantially planar face  18  of female connector block  20  and that passes through fastener passage  36  upon assembly of the connection, will slightly crush protuberance  34  tending to cause the faces  16  and  18  of blocks  12  and  20  to become parallel. As a result, gaps and unbalanced forces between faces  12  and  18  are avoided, thereby providing the best possible axial seal. The anti-cantilever effect of crushed protuberance  34  improves the consistency and adequacy of the axial seal by eliminating or reducing cantilevering effects caused by unpredictable dimensional variations of multiple components during manufacturing. 
     Tubular fluid conduit  14  is provided with a circumferential groove  44  on a portion of conduit  14  that protrudes outwardly from conduit passage  22  (i.e., to the right of face  16  in  FIG. 1 ) and away from the generally planar face  16  of male connector block  12 . 
     Located within circumferential groove  44  is a sealing ring  46  (e.g., an elastomeric O-ring). Sealing ring  46  includes an outward circumferential surface  48  contacting a surface of a conduit receiving passage  49  in female connector block  20 , and an inward circumferential surface  50  sealingly contacting groove  44 . Sealing ring  46  provides a radial seal between tubular fluid conduit  14  and conduit receiving passage  49  in female connector block  20 . 
     As shown in  FIG. 1 , conduit  14  can be immobilized in the first cylindrical bore  26  of conduit passage  22  with spaced apart crimps  30  and  52 . Crimp  30  engages a bottom surface  54  of second cylindrical bore  28 , and crimp  52  engages a surface of back side  24  of block  20 . 
     A single fastener can be used for forming a sealed connection between conduit  14  secured to male connector block  12  and a conduit  56  secured to female connector block  20 . In the illustrated embodiment, female block  20  is provided with an integral threaded stud  42  that is adapted to pass through fastener passage  36 . A nut  58  is used for compressing surfaces  16  and  18  together to form a fluid-tight connection. Fastener passage  36  is located between conduit passage  22  and protuberance  34 . 
     Sealing ring  46  is preferably made of an elastomeric material. A preferred elastomeric material for sealing ring  46  is hydrogenated nitrile butadiene rubber (HNBR). Sealing ring  46  is preferably lubricated, such as with polyalkylene glycol (PAG oil) or silicon oil to allow sealing ring  46  to more easily slide along surfaces of conduit receiving passage  49  to avoid pinching and undesirable deformation of sealing ring  46  during assembly of a leak resistant connection. Alternatively, or additionally, sealing ring  46  can be provided with a polytetrafluoroethylene coating to eliminate or reduce unwanted pinching and other deformation of ring  46 . 
     Seal washer  32  is preferably comprised of a metal (e.g., aluminum or steel) washer portion  32 A that has a thickness approximately equal to the difference between the depth of counter bore  28  and the longitudinal thickness of crimped section  30 , and an elastomeric portion  32 B that can be made of the same elastomeric material used to make sealing ring  46 , but is more preferably comprised of a different elastomer. In a particularly preferred embodiment, seal washer  32  is made of ethylene propylene diene monomer (EPDM) rubber. Having two different elastomeric materials used for washer  32  and ring  46 , such as EPDM for washer  32  and HNBR for ring  46 , provides better overall performance, especially under extreme conditions, such as extreme temperatures. For example, EPDM has better low temperature sealing capability and HNBR has better high temperature sealing capability. The metal washer portion  32 A and elastomeric portion  32 B can be mechanically joined such as with splines at interface  32 C. Alternatively, or additionally, the washer portion and elastomeric portion of seal washer  32  can be chemically joined (e.g., with an adhesive material). The elastomeric portion  32 B of seal washer  32  can have a tear-drop-like cross-sectional profile as shown in  FIG. 5  that is compressed within the remaining space between crimp  30  and female connector block  20  that is not occupied by washer portion  32 A upon complete assembly of the connection. 
     Conduit receiving passage  49  preferably has walls defined by a truncated conical shape, which leads sealing ring  46  into passage  46  with reduced pinching. As an example, the half angle of the truncated conical shape can be from about 5 degrees to 25 degrees, such as 10 degrees to 20 degrees, 15 degrees to 20 degrees, or about 18 degrees. 
     The combination of features provides a non-cantilever seal, wherein leakage past the O-ring  46  can be blocked by seal washer  32 . 
     Accordingly, it is to be understood that the above description is intended to be illustrative and not restrictive. Many embodiments and applications other than the examples provided would be apparent upon reading the above description. The scope of the invention should be determined with reference to the appended claims along with the full scope of equivalents to which such claims are entitled. It is anticipated and intended that future developments will occur, and that the disclosed systems and methods will be incorporated into such future embodiments. In summary, it should be understood that the invention is capable of modification and variation.