Abstract:
A generally cylindrical quick disconnect female cryogenic coupler, interconnected with a cryogenic fluid transfer apparatus, includes a coupler body with a first cavity housing a laterally severed tubular bushing, an adaptor having one end attached to the coupler body and another end to the apparatus, a normally closed-biased valve between the coupler body and the adaptor, a coupling sleeve, attached to the coupler body having, a frusto-conical inlet portion, and a vent fitting having one end connected with a coupling sleeve radial aperture and another end in operative connection with a cryogenic fluid storage vessel, associated with the noted apparatus, to permit the inlet purging by using the vessel&#39;s own gaseous phase as a purging medium during liquid fluid transfer operation. The severed bushing inhibits ice formation, at an inlet/male nipple interface during the noted transfer. A method for purging moisture at the noted interface is also set forth.

Description:
CROSS-REFERENCE TO RELATED CASE 
   The present application claims the benefits of the filing date of U.S. Provisional Application No. 60/591,288, filed Jul. 27, 2004. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention pertains to quick disconnect couplers operatively inter-connected with a cryogenic liquid fluid transfer apparatus and associated with a cryogenic fluid storage vessel. Specifically, the invention pertains to the use of a laterally severed tubular bushing that serves to inhibit ice formation, at a coupler inlet/male nipple interface during liquid fluid transfer. In addition, a vent fitting, having one end attached to radial aperture in a coupling sleeve inlet portion, and another end in operative connection with the cryogenic storage vessel, permits inlet purging by using the vessel&#39;s own gaseous phase as a purging medium during the liquid fluid transfer operation. 
   Quick disconnect couplers are well known and are utilized in every conceivable type of fluid transfer application. One of the intended types of end products utilizing the quick disconnect cryogenic coupler of the present invention are portable liquid oxygen units. Such units, in one application, are typically used by patients suffering from Chronic Obstructive Pulmonary Disease (COPD) and provide them with oxygen. In such an apparatus, liquid oxygen, stored in a small cryogenic dewer, is converted to breathable gas, via a warming mechanism, thereby providing the patient with warmed O 2  at a given pressure and flow rate. For such applications, the portable cryogenic dewers are filled from larger stationary refill tanks, with the cryogenic coupler of this invention being utilized in such cryogenic liquid fluid transfer apparatuses. It should be understood that cryogenic couplers are also utilized in other cryogenic applications, not just at the end product, but also at the end of fluid transfer apparatuses, such as hoses, tubing or ducting, and with Liquid Natural Gs (LNG) couplings and the like. 
   In terms of the operation, the male half of the coupling, namely the nipple, is inserted into the female half of the coupling, namely the coupler. Internal valves in both halves are opened as the coupler and nipple are united, with a complete coupling connection therebetween constituting the “coupling”. Once both internal valves are open, liquid fluid is allowed to flow from the nipple into and through the coupler. Once the desired amount of fluid has passed through the coupling, the two halves are pulled apart, with this disconnection process also allowing the two internal valves to shut, thereby preventing any further fluid transfer through the coupler. 
   Cryogenic fluid transfer, due in large part to the great difference in the ambient temperature and that of the fluid being transferred, involves icing, due mainly to condensation, particularly at the nipple/coupler interface. One known method of reducing such icing is to utilize a thermal break angle, between the nipple and coupler, by incorporating, in the sleeve of the coupler, of an about 10 degree change in its inlet diameter, thereby allowing a thermal break during the noted refill process. Such a construction allows an air break between the coupler and the nipple, thus preventing ice from freezing the two halves together. 
   Another known way for reducing ice formation between the two coupling halves is the use of a purge mechanism, such as a purging medium, e.g., an external purge gas, such as compressed air. Such purging does remove moisture but requires an additional, external supply of a purging medium. 
   2. Description of the Related Art 
   The patent literature sets forth a large number of cryogenic coupling constructions, some of which include: U.S. Pat. No. 3,842,614 to Karcher et al.; U.S. Pat. No. 5,265,844 to Westfall; U.S. Pat. No. 5,363,879 to Rhoades; U.S. Pat. No. 5,429,155 to Brzyski et al.: U.S. Pat. No. 5,880,043 to Lorenz et al.; U.S. Pat. No. 6,047,553 to Germain; U.S. Pat. No. 6,079,446 to Tocha; U.S. Pat. No. 6,145,322 to Odajima; and U.S. Pat. No. 6,539,970 B1 to Knowles et al. However, none of these prior art structures include the use of a laterally severed tubular bushing that functions as an anti-freezing lining inside the coupler, relative to the adjoining nipple portion. In addition, all of the prior art structures utilize an external source for a purge medium, not the purging gas emanating from the unit being charged or refilled with the liquid phase of the purging gas. 
   SUMMARY OF THE INVENTION 
   Accordingly, in order to overcome the deficiencies of the prior art devices, the present invention provides a quick disconnect coupler that includes the use of a laterally severed bushing that functions as an anti-freezing lining inside the coupler, relative to an adjoining nipple portion. In addition, the purging medium utilized in removing moisture from the coupler/nipple interface is the own internal gas that is purged from the unit being charged or refilled with the liquid phase of the same composition. 
   Specifically, in terms of structure, in this invention, a quick disconnect coupler, operatively interconnected with a cryogenic fluid transfer apparatus, the coupler comprising in combination: a. a generally cylindrical coupler body having a through bore and a front cylindrical portion with a first cavity open on one end, separated from a rear portion with a second cavity open on another end, via an apertured intermediate wall portion perpendicular on a first side facing the first cavity and including a tapered wall portion on a second side facing the second cavity; b. the first cavity having an inner peripheral surface surrounding an outer peripheral surface of a laterally severed tubular bushing, with the condition of being severed permitting a predetermined amount of radial expansion of the bushing; c. a generally tubular adaptor having a second through bore and a cylindrical rear portion, operatively attached to the cryogenic fluid transfer apparatus, a cylindrical, apertured, intermediate portion including a valve guide, located in the through bore, and a cylindrical front portion sealingly, operatively, connected with to the coupler body rear portion; d. an annular interface seal, spaced from the coupler body intermediate wall portion, the spacing of the seal permitting a limited amount of axial movement of the tubular housing; e. a valve, normally biased to a closed position, interposed between the valve guide and the coupler body tapered wall portion, with a valve head portion shutting the apertured intermediate wall portion in the closed position thereof; and f. a generally tubular coupling sleeve having a frusto-conical front inlet portion separated from a cylindrical outlet portion via an annular end face adjoining the front inlet portion, the coupling sleeve being operatively secured to the coupler body front portion, with the annular end face physically abutting the first cavity. 
   In one version, the severed tubular bushing is comprised of a polymeric composition material, preferably of one of a PTFE composition material and PTFE equivalent material composition. 
   In another version, the tubular bushing is severed from one peripheral edge to the other peripheral edge in a diagonal manner, preferably in the form of a scarf-cut. 
   In a further version, the outside diameter of the tubular bushing is radially spaced, a predetermined distance, from the inner peripheral surface of the first cavity inner peripheral surface, so as to permit a predetermined amount of radial movement therebetween. 
   In still another version, the frusto-conical front inlet portion of the coupling sleeve further includes a radial aperture, with this aperture being operatively connected with one end of a vent fitting, with another end of the fitting being in an operative connection with a cryogenic fluid storage tank of a cryogenic device associated with the cryogenic fluid transfer apparatus. 
   In a variation of the above version, the operative connection with the cryogenic fluid storage tank includes a flow control valve, with the flow control valve preferably being associated with the cryogenic fluid storage tank. 
   In another variation of the above version, the operative connection with the cryogenic fluid storage tank is at a position in the tank that is filled with a gaseous fluid, with the operative connection of the coupling sleeve front inlet portion with the cryogenic fluid storage tank of the cryogenic device permitting the purging of the inlet portion by utilizing the cryogenic device&#39;s own gaseous fluid as the purge mechanism, in the form of a moisture remover, during the cryogenic liquid fluid transfer operation. 
   A differing version further includes a male nipple assembly releasably joined with the coupler via an operative interconnection. 
   In one variation the preceding version, the operative interconnection includes, in the nipple assembly, an inner end portion adapted to be inserted into the coupler via the coupler sleeve inlet portion and making a sealing contact with the inner peripheral surface of the annular interface seal, the severed bushing, via the limited amounts of axial radial movements, aiding in the prevention of icing, at the sealing contact, during the cryogenic liquid fluid transfer operation. 
   In another variation of the preceding version, the coupling front inlet portion further includes a radial aperture, the aperture being operatively interconnected with one end of a vent fitting, with another end of the vent fitting, in turn, being in an operative interconnection with a cryogenic fluid storage vessel of a cryogenic device associated with the cryogenic fluid transfer apparatus. The operative interconnection of the coupling sleeve inlet portion with the cryogenic fluid storage vessel permits the purging of the inlet portion and the adjacent nipple inner end portion by utilizing the cryogenic device&#39;s own gaseous fluid as the purging medium, in the form of moisture removal, during the cryogenic liquid fluid transfer operation. 
   In a further variation of the preceding version, the operative interconnection further includes, in the outer peripheral surface of one of the coupling sleeve and coupler body, at least one, radially outwardly-directed, cylindrical pin, the at least one pin being adapted to releasably mate, in a twisting motion, with one of at least one bayonet slot, formed in a cup member concentric and connected with the nipple assembly inner end portion. 
   In a differing variation of the preceding version, the operative interconnection with the cryogenic fluid storage vessel is at a position in the vessel that is filled with the gaseous phase of the cryogenic liquid fluid therein. 
   In another embodiment of the present invention, in a quick disconnect coupler and male nipple assembly combination, associated with a cryogenic fluid transfer apparatus, there is set forth a method for purging moisture from the interface of a coupling sleeve inlet portion and an adjacent nipple inner end portion, the method comprising the steps of: a. providing the inlet portion, at the interface, with a radial aperture; b. connecting one end of a vent fitting with the aperture; c. operatively connecting another end of the fitting with a cryogenic fluid storage vessel of a cryogenic device also associated with the cryogenic fluid transfer apparatus; and d. utilizing the cryogenic device&#39;s own gaseous fluid as a purging medium, for removing moisture, at the interface, during the cryogenic liquid fluid transfer operation. 
   In another version, the previous method further includes: e. locating one end of the operatively connecting step at a position in the storage vessel that is filled with the gaseous phase of the cryogenic liquid fluid residing therein. 
   In a further version, the method also includes: f. interposing a flow control valve between the vent fitting and the cryogenic fluid storage vessel. 
   In a differing version, the method additionally includes: g. opening the flow control valve during the cryogenic liquid fluid transfer operation; and h. closing the flow control valve upon cessation of the transfer operation. 
   Another embodiment of this invention pertains to a quick disconnect coupler, operatively interconnected with a cryogenic fluid transfer apparatus, the coupler comprising in combination: a. a generally cylindrical coupler body having a through bore and a front cylindrical portion with a first cavity open on one end, separated from a rear portion with a second cavity open at another end, via an apertured intermediate wall portion perpendicular on a first side facing the first cavity and including a tapered wall portion on a second side facing the second cavity; b. the first cavity surrounding an outer peripheral surface of a tubular bushing; c. an annular interface seal, located at one axial end of the bushing, permitting a limited amount of axial movement of the bushing; d. a generally tubular adaptor having a second through bore and a cylindrical rear portion, operatively attached to the cryogenic fluid transfer apparatus, a cylindrical, apertured, intermediate portion including a valve guide, located in the through bore, and a cylindrical front portion sealingly, operatively, connected to the body rear portion; e. a valve, normally biased to a closed position, interposed between the valve guide and the coupler body tapered wall portion, with a valve head portion thereof shutting the apertured intermediate wall portion in the closed position; f. a generally tubular coupling sleeve having a frusto-conical front inlet portion separated from a cylindrical outlet portion via an annular end face adjoining the front inlet portion, the coupling sleeve being operatively secured to the coupler body front portion, with the annular end face physically abutting the first cavity; and g. a vent fitting having one end thereof connected with a radial aperture in the coupling sleeve front inlet portion, and another end of the vent fitting being in an operative connection with a cryogenic fluid storage vessel associated with the cryogenic fluid transfer apparatus, wherein the operative connection permits purging of the inlet portion by utilizing the cryogenic vessel&#39;s own gaseous phase as a purging medium, for moisture removal, during the transfer operation. 
   In one version thereof, the operative connection between the coupler and the cryogenic fluid storage vessel includes a flow control valve, with the flow control valve being associated with the cryogenic fluid storage vessel. 
   In another version thereof, the operative connection with the cryogenic fluid storage vessel is at a position in the vessel that is filled with a gaseous phase of the cryogenic fluid. 
   A differing version thereof, further includes a male nipple assembly releasably joined with the coupler via a further operative interconnection, with the further operative connection includes, in the nipple assembly, an inner end portion adapted to be inserted into the coupler via the coupler sleeve inlet portion and making a sealing contact with the inner peripheral surface of the annular interface seal and permitting the purging of the inlet portion and the adjacent nipple inner end portion. The tubular bushing is severed from one peripheral edge to the other peripheral edge in other than a direct lateral cut. The bushing is preferably scarf-cut, the cut aiding in the prevention of icing at a sealing contact between the inner peripheral surface of the annular interface seal and the adjoining male nipple portion, with the scarf-cut tubular bushing preferably being comprised of a polymeric material of a PTFE composition or a PTFE equivalent-type composition. 
   In yet a further version thereof, the outside diameter of the severed tubular bushing is radially spaced, a predetermined distance, from the inner peripheral surface of the coupler body first cavity, so as to permit a predetermined amount of radial movement therebetween. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       FIG. 1  is a perspective view of a first embodiment of a quick disconnect cryogenic coupler of the present invention; 
       FIG. 2  is a view of the coupling end of the coupler of  FIG. 1 ; 
       FIG. 3  is a view, similar to that of  FIG. 1  but partly in section for the sake of clarity; 
       FIG. 4  is s vertical, longitudinal, side view, partly in section, similar to that of  FIG. 3 ; 
       FIG. 5  is a perspective view of a second embodiment of a quick disconnect cryogenic coupler of the present invention, adjacent to a known nipple, shown in an uncoupled position; 
       FIG. 6  is a vertical, longitudinal, side view, partly in section, of the  FIG. 5  coupler and adjacent nipple, in the uncoupled position; 
       FIG. 7  is a perspective view, similar to that of  FIG. 5 , but partly in section, of the second embodiment of the quick disconnect coupler of the present invention, shown in a coupled position with the known nipple; 
       FIG. 8  is a vertical, longitudinal, side view, similar to that of  FIG. 6  but showing the coupled position; 
       FIG. 9  is a schematic layout, mainly in section, of a tank of a portable cryogenic device, e.g. for holding liquid oxygen, or the like, shown during refill, which is the mode of operation thereof in which the quick disconnect couplers of the present invention can be utilized; and 
       FIG. 10  is a rotated side view of the tank of  FIG. 9 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring now to the several drawings, illustrated in  FIGS. 1-4  is a first embodiment of the quick disconnect cryogenic coupler of the present invention, generally indicated at  20 , with coupler  20  being basically comprised of the combination of at least five major components, namely: a coupler body  22 , an adaptor  24 , a coupling sleeve  26 , a valve assembly  28 , a split bushing  30  in coupler body  22 ; and an optional vent fitting  32  in coupling sleeve  26 . Coupler  20  is adapted to be releasably connected with any desired, known, male nipple (not shown in this embodiment) in order to transfer the cryogenic fluid. It should be understood that with coupler  20 , no separate device is utilized to for locking same to the male nipple, rather, coupler  20  is physically held onto the male nipple with an external force being applied to the unit ( FIG. 9 ) in which coupler  20  is installed. 
   Specifically, coupler body  22 , which is generally cylindrical in shape, has an exterior threaded portion  34  and a cylindrical first or front cavity  36 , in a front portion  35 , separated from a rear or second cavity  38 , in a rear portion  37 , by an apertured intermediate wall portion  40  that is perpendicular on the side  42  facing first cavity  36  and frusto-conically tapered on the side  44  facing second cavity  38 . Second cavity  38  includes an internally threaded cylindrical portion  48  and an end recess shoulder area  50  and may also include opposing exterior tool or wrench-receiving flat portions  52 . 
   Adaptor  24 , which is generally tubular in shape, has a reduced diameter externally-threaded cylindrical front portion  56  adapted to mate with coupler body internally threaded portion  48 , and an adjoining recess shoulder area  58  which cooperates with coupler body shoulder area  50  to receive and confine a flexible seal member  62 , to produce a leak-free environment therebetween. The interior of threaded front portion  56  defines a third cavity  60  that partially coincides with second cavity  38 . An exterior threaded rear portion  64  is separated from front portion  56  via a larger diameter generally cylindrical intermediate portion  66  having opposed external tool or wrench-receiving portions  68 . Rear portion  64  is adapted to be fixedly secured to a cryogenic vessel or tank  106 , at about mid-height thereof, in the manner schematically shown in  FIG. 9 , which will be discussed in detail later. Adaptor  24  is further provided with a multi-diameter through bore  70  that includes an apertured valve guide  72 , preferably in the form of a bridge, perch, or spider member, in adaptor intermediate portion  66  that serves to seat one end of a known or conventional valve assembly  28 . Valve guide  72  may be formed integrally with adaptor  24  or inserted thereinto as a separate part. Valve assembly  28  includes a central stem portion  74  having a head portion  76  and a retainer portion  78 , with an annular polymer seal  80 , preferably of a PTFE or PCTFE, etc. composition being interposed therebetween, and a coil spring  81  for normally biasing seal  80  into a sealing relationship with coupler body frusto-conical wall portion  44 . 
   Returning now to coupler body  22 , the inner peripheral surface of its front or first cavity  36  is provided with an anti-icing, slit, tubular, bushing  30 , that is severed, e.g., by slicing or cutting axially across one side, from one edge to the other, preferably, but not limited to, in a diagonal manner  82  as shown in  FIG. 3 , with this type of cut often being referred to as a “scarf-cut”. Such a cut  82  allows bushing  30  to diametrically or radially move and/or expand over the male nipple (not shown here) and/or any ice build-up thereon, while being disconnected from coupler  20 . While scarf-cut technology is currently used for seals and back-up rings, etc., the use thereof in this invention now incorporates and expands this technology to anti-icing bushings utilized for cryogenic liquid transfer and filling of cryogenic fluid holding containers or vessels, often referred to as “dewers”. In addition, the outside diameter of bushing  30  is radially spaced, a predetermined distance, from the inner peripheral surface of first cavity  36 , so as to permit a predetermined amount of radial movement therebetween. Cut bushing  30  may be constructed of any desired material but is preferably constructed of a polymer material, such as PTFE or equivalents thereof, and is installed during the assembly of coupling  20 . Bushing  30  may be loosely axially confined within cavity  36  in any known manner or method, e.g., via a known annular seal member  86  of any desired composition or material, e.g., of a polymeric composition, with seal member  86  preferably being retained in a recess  88  in cavity  36 . As best seen in  FIG. 4 , the placement of seal member  86  allows for some limited axial movement thereof within cavity  36 . 
   Turning now to coupling sleeve  26 , which is of a generally tubular shape, it includes a front or inlet diameter frusto-conical portion  90  having a known, tapered break angle  92 , e.g., of an about 10 degree change in inlet diameter, allowing a thermal break during the refill process. This construction permits an air break between coupler  20  and the male nipple, thereby preventing ice from freezing these parts together. The outer peripheral surface of sleeve  26  may be provided with opposed tool or wrench-receiving flat surfaces  95 . A generally cylindrical, internally-threaded, outlet portion  94  of sleeve  26  is separated from inlet diameter portion  90  via an annular end face  96 , which, upon assembly with coupling body  22  operatively abuts cavity  36 . Inlet diameter portion  90  is also provided with a radial aperture  97  that is adapted to fixedly receive one end  98  of vent fitting  32 , with the other end  100  thereof being adapted for connection, via a hose/conduit/line  102 , with any type of a desired, known, flow control valve  104 , e.g., a manually-operated vent valve, which, in turn, is operatively connected with a cryogenic tank or dewer  106 , preferably close to its maximum vertical height, as schematically shown in  FIG. 9 . It should be understood that, depending upon the type of application, the use of a valve  104  may not be necessary since this internal source of gas that is being utilized as a purging gas can be directly routed from tank  106  to coupler  20 . 
     FIG. 9  illustrates valve  104  in its open position which allows the use of gas, vented from tank  106 , during filling thereof, via cryogenic coupler  20 , to purge moisture from the coupler/nipple interface. Thus, vent line  102 , from valve  104 , is connected to coupling sleeve  26 , thereby permitting the use of the normally vented gas, from the inside of dewer  106 , to aid in moisture removal at the noted interface. Upon the cessation of the filling cycle or operation, valve  104 , is shifted or returned to its closed position. 
   In terms of the assembly of coupler  20 , coupler body  22 , adaptor  24  and coupling sleeve  26  are threaded together and act as a single unit in the finished assembly. Valve assembly  28  is captured or confined in the facing cavities of coupler body  22  and adaptor  24  and acts as the fluid shut-off device upon the disconnection of the male nipple. Anti-icing slit bushing  30  is installed in coupler body  22  during the assembly of coupling  20  and is held in place, e.g., by seal member  86  or the like. 
   In terms of the operation of coupler  20 , the previously noted male half, or nipple (not shown), is inserted into coupler sleeve inlet diameter portion  90 . During this insertion, internal valves, such as valve  28 , in both halves are opened as coupler  20  is pushed further onto the nipple, with a complete connection between coupler  20  and the nipple providing a “coupling” therebetween. At this time, if moisture removal, at the coupler/nipple interface is desired, valve  104  is manually moved from its normally closed position, to its open position, thereby permitting the use of the gas being vented from dewer  106  to aid in moisture removal at the noted interface. With both internal valve halves or valve portions open, fluid is allowed to flow from the nipple into and through coupler  20 . When the amount of desired fluid flow has passed through the coupling, valve  104  is returned to its normally closed position. Subsequently, the coupler and nipple halves are pulled apart. This “disconnection” process also allows the noted internal valves to close or shut, thereby preventing any further fluid transfer through coupler  20 . 
   Continuing now with  FIGS. 5-8 , illustrated therein is a second embodiment of the quick disconnect cryogenic coupler of the present invention, generally indicated at  20 ′.  FIGS. 5 and 6  illustrate coupler  20 ′ and a nipple assembly  110  in the uncoupled position, whereas  FIGS. 7 and 8  illustrate same in the coupled position. Coupler  20 ′ is similar to coupler  20 , with like parts being denominated with the same numeral and the addition of a prime (′) superscript as a suffix. 
   Specifically, coupler body  22 ′ together with cut bushing  30 ′ and seal member  86 ′ is substantially similar to coupler body  22 , bushing  30  and seal member  86 . Adaptor  24 ′ differs from adaptor  24  only by the addition, to intermediate portion  66 ′, of an exterior threaded portion  114  and a complementary nut member  116 . Coupler sleeve  26 ′ differs from coupler sleeve  26  mainly in that coupler  26 ′ has a generally tubular outer peripheral surface  122  that includes a recessed diameter frontal portion  118  that is provided with at least one and preferably a pair of opposite, radially outwardly-directed, boss portions or pins  120  (only one of which is shown) that are adapted to mate, in a twisting motion, with opposed bayonet slots  162  in a cap portion  150  of known nipple assembly  110  of any desired construction. 
   Known nipple assembly  110  includes an elongated, generally tubular body  126  which may be provided with hexagonal outer, flat, surface portions  136 , if so desired. An inner end of body  126  is provided with an annular end surface  128  having a central aperture  130  and an inner frusto-conically tapered portion  132 . In addition, body  126  includes a through bore  134  and is provided with an apertured valve guide  138 , in bore  134  that serves to seat one end of a known or conventional valve assembly  140 , similar to those of valve assemblies  28  and  28 ′, which, in the interest of brevity, will not be discussed further. Suffice it to say, head portion  142  of valve  140  extends through central aperture  130  akin to that of head portion  76  of valve  28 , as best seen in  FIG. 4 . 
   Body flat surface portions  136  also include a peripheral recess  146  that serves, in conjunction with at least one metal retainer ring  148 , to axially and circumferentially retain an inner annular end portion  152  of a peripheral cup member  150  that surrounds the inner end portion  144  of body  126 . Annular end portion  152  is provided with a plurality of preferably evenly peripherally spaced ventilating holes  156 . Cup member  150  also includes a generally cylindrical portion  160  on its open inner end, with portion  160  being attached to annular end portion  152  at one end. Cylindrical portion  160  is provided with at least one and preferably with a pair of opposed bayonet slots  162  as well as a pair of opposed, elongated, slots  164 , which function as thermal breaks that are axially spaced from bayonet slots  162 . It should be evident from the noted drawings, particularly form  FIGS. 7 and 8 , that the inside diameter  166  of cylindrical portion  160  is sized for a slip fit relationship with maximum diameter portion  122  of coupler sleeve  26 ′. 
   In terms of the operation of coupler  20 ′, as best seen in  FIGS. 6 and 8 , the male half or nipple assembly  110 , specifically, inner end portion  144  thereof, is inserted into coupler sleeve inlet diameter portion  90 ′ and makes sealing contact with the inner diameter of annular seal member  86 . During this insertion, both internal valves  28 ′ and  140  are opened via the abutments of their respective heads  76 ′ and  142 , in the manner already previously described. Although not shown in  FIGS. 5-8 , it should be understood that a further bayonet slot (not shown) can be provided, in cup member  150 , to accommodate a vent fitting  32 ′ (not shown), if so desired. In addition, if deemed necessary, one or both of surfaces  166  and  122  can be provided with a coating or band of a polymer material, such as PTFE or the like, in order to minimize the possibilities of ice formation and subsequent freezing therebetween. 
   Again, it should be understood that illustrated nipple assembly  110  is merely representative of the types of nipple assemblies that can be utilized and interchanged with couplers  20  and  20 ′ and forms no part of the present invention. There is no presently known standard (such as ISO or ANSI, etc.) for the nipple profile set forth herein. Similarly, although while a bayonet-type of mechanical coupling is shown and described, other types of known couplings, if a mechanical coupling is desired, may be utilized. 
   It should further be understood that the operative interconnection between coupler  20  or coupler  20 ′ with a male nipple assembly, such as  110 , that this operative interconnection includes the insertion of nipple inner end portion  144  into coupler sleeve inlet portion  90  and/or  90 ′ and makes sealing contact with the inner peripheral surface of annular interface seal  86  and, importantly so, severed tubular bushing  30 , by virtue of its limited amounts of both axial and radial movements, within first cavity  36 , aids in the prevention of icing, at the noted sealing contact, during the cryogenic liquid fluid transfer operation. In addition, these radial and axial movements of bushing  30  allows bushing  30  to move and/or expand over nipple inner end portion  144  (and/or any ice buildup thereon) while being disconnected from coupler  90  and/or  90 ′. 
   It is deemed that one of ordinary skill in the art will readily recognize that the several embodiments of the present invention fill remaining needs in this art and will be able to affect various changes, substitutions of equivalents and various other aspects of the invention as described herein. Thus, it is intended that the protection granted hereon be limited only by the scope of the appended claims and their equivalents.