Tubing coupler with primary and secondary sealing

A tubing coupler for mechanically and fluidly connecting two pieces of tubing. The tubing coupler has a first body portion with a pilot and a second body portion with a cavity in which the pilot is disposed when the tubing coupler is assembled. A fluid passageway through the first body portion and the pilot of the first body portion is in fluid communication with a fluid passageway through the second body portion and the cavity of the second body portion. Thus fluid flow is allowed through the coupler. A primary sealing device circumscribes the pilot of the first body portion and seals the space between the pilot of the first body portion and the cavity of the second body portion. A plate is disposed between the first body portion and the second body portion and defines an opening through itself through which the pilot of the first body portion protrudes. A secondary sealing device is disposed inside the periphery of the opening in the plate and surrounds a portion of the pilot. The secondary sealing device is elastically compressed between the first body portion and second body portion and acts as a back up for the primary seal.

BACKGROUND OF THE INVENTION
 This invention relates to a tubing coupler that has primary and secondary
 sealing devices. The coupler is designed such that if the primary sealing
 device fails the secondary sealing device will prevent the travel of fluid
 between the interior of the system and the outside atmosphere. The coupler
 is further designed such that, if necessary, it can be assembled without
 the secondary sealing device and function properly, provided the primary
 sealing device does not fail. The coupler can also be disassembled and
 subsequently reassembled with the original primary and secondary sealing
 devices.
 RELATED ART
 Tubing couplers similar to the present invention are known in the art.
 These tubing couplers have a first body portion for attachment to the end
 of a first tube and a separate, second body portion for attachment to the
 end of a second tube. The first body portion defines a first passageway
 through itself and the second body portion defines a second passageway
 through itself. Each respective tube is affixed to each respective body
 portion such that the interior of the tube is in fluid communication with
 the respective passageway through the respective body portion.
 When the tubing coupler of the prior art is in use the first and second
 body portions are assembled together as a unit, but can be disassembled to
 allow service of the tubing, the coupler, or the system containing the
 tubing and the coupler. A surface other than one adjacent the point of
 attachment of the first tube, defines a first mating face on the first
 body. A surface other than one adjacent the point of attachment of the
 second tube, defines a second mating face on the second body. When the
 coupler is assembled the first mating face abuts the second mating face
 and means are provided for urging the two faces together. A pilot projects
 from the first mating face of the first body portion. The first passageway
 through the first body portion extends through the pilot and terminates at
 an opening in the end of the pilot. The first tube is attached to the
 first body portion adjacent the end of the first passageway which is
 opposite the opening in the end of the pilot. The end of the second
 passageway through the second body portion, which is opposite the second
 tube, terminates at an opening in the second mating face of the second
 body portion. The end of the second passageway adjacent the opening in the
 second mating face of the second body portion of the coupler, defines a
 cavity similar in shape and slightly larger than, the pilot which projects
 from the first mating face of the first body portion. When the coupler is
 assembled, the pilot of the first body portion is positioned within the
 cavity defined by the end of the second passageway and a small space is
 defined concentrically between the pilot and the cavity. The first
 passageway of the first body portion is thus in fluid communication with
 the second passageway of the second body portion. The first and second
 passageways are also in fluid communication with the first and second
 tubes respectively.
 Similar to the present invention the known tubing couplers have primary and
 secondary sealing devices. A primary sealing device circumscribes the
 pilot and is disposed in the space between the pilot of the first body
 portion and the cavity defined by the end of the second passageway of the
 second body portion. This primary sealing device, thus, prevents fluid
 from traveling between the first or second passageways of the coupler and
 the outside atmosphere. A secondary sealing device is interposed between
 the first and second mating faces and surrounds both the pilot of the
 first body portion and the opening of the second passageway in the second
 mating face of the second body portion. This secondary sealing device
 prevents fluid from traveling between the first or second passageways of
 the coupler and the outside atmosphere through spaces, which may be
 present, between the first and second mating faces. The secondary sealing
 device is included in the coupler as a backup for the primary sealing
 device and is only relied upon to seal the coupler in the event that the
 primary seal fails.
 While the known tubing couplers have many advantages, there are some
 aspects of their design which make them less than ideal. Many of the known
 tubing couplers have metallic secondary sealing devices which require
 elaborate machining of one or both mating faces of the coupler. In
 addition, these metallic sealing devices are often designed to be
 plastically deformed upon assembly of the coupler and must therefore be
 replaced with a new sealing device any time the coupler is disassembled
 and subsequently reassembled. In other designs of known couplers, the
 secondary sealing device is positioned within (a) recess(es) in one or
 both of the mating faces of the coupler. This design also requires costly
 machine work to be performed on the mating face(s) of the coupler. This
 design further requires the mating faces of the coupler to be larger than
 would otherwise be necessary. The increased size of the mating faces is
 necessary to allow room for the recess, and sufficient material
 surrounding the recess to contain the secondary sealing device. Finally,
 this design requires that the depth of the recess(es) in the mating faces
 be held within a very small tolerance range. If the recess(es) in the
 mating face(s) are too deep the secondary sealing device will not properly
 contact both of the body portions of the coupler and will not seal. If the
 recess(es) in the mating face(s) of the coupler are too shallow the
 secondary sealing device can be damaged by being compressed too far or can
 prevent the mating faces of the coupler from properly abutting. Another
 drawback of most designs of the known tubing couplers is that they can not
 be assembled without the secondary sealing device and still function
 properly.
 SUMMARY OF INVENTION
 As a result, there are a number of objects of the present invention. One
 object of the present invention is to provide a tubing coupler, which does
 not require elaborate machine work to be performed on either of the mating
 faces of the body portions of the coupler. Another object of the present
 invention is to provide a tubing coupler with primary and secondary
 sealing devices that can be reused upon disassembly and subsequent
 assembly of the tubing coupler. A final object of the invention is to
 provide a tubing coupler which can be assembled without a secondary
 sealing device, in the event that a secondary sealing device is
 temporarily unavailable, and still function properly provided that the
 primary sealing device does not fail.
 The tubing coupler of the present invention is comprised of a first body
 portion, a separate second body portion, a plate and one or more clamping
 devices to maintain the parts of the tubing coupler in an assembled state.
 The first body portion of the tubing coupler has a first mating face with
 a pilot projecting from that first mating face. The first body portion
 defines a first passageway which begins at an opening in the end of the
 pilot which projects from the first mating face of the first body portion,
 travels through the first body portion, and terminates at an opening on an
 outer surface. The second body portion of the tubing coupler has a second
 mating face. The second body portion defines a second passageway which
 begins at a first opening in the second mating face of the second body
 portion, travels through the second body portion, and terminates at an
 opening on an outer surface of the second body portion. A portion of the
 inner surface of the second passageway adjacent to the first opening in
 the second mating face of the second body portion defines a cavity. The
 cavity is of the same general shape, and is slightly larger than the pilot
 which projects from the first mating face. When the tubing coupler is
 assembled, the pilot projecting from the first mating face of the first
 body portion of the tubing coupler is disposed within the cavity at the
 end of the second passageway adjacent the opening in the second mating
 face. The plate of the coupler defines a first opening through itself of
 sufficient size to allow the pilot to protrude through this first opening
 in the plate. In the coupler's assembled state the plate is sandwiched
 between the first body portion and the second body portion and the pilot
 protrudes through the first opening in the plate. A primary sealing device
 circumscribes the pilot and seals the space between the pilot and the
 cavity defined by the second passageway of the second body portion. A
 secondary sealing device is positioned within the first opening in the
 plate, and when the coupler is assembled surrounds both a portion of the
 pilot and the first opening in the second mating face adjacent the end of
 the second passageway. The secondary sealing device is compressed between
 the first mating face and the second mating face and fills spaces between
 the first mating face, the plate, and the second mating face through which
 fluid could otherwise travel.
 It can thus be seen that the tubing coupler of the present invention
 satisfies all of the objects of the invention. The mating faces of the
 first body portion and the second body portion can be substantially planar
 and do not require elaborate machine work. Neither of the first or second
 sealing devices is deformed plastically when the tubing coupler is
 assembled. Therefore the sealing devices can be reused when the coupler is
 reassembled after having been disassembled. The springy nature of the
 secondary sealing device, the fact that it is slightly thicker than the
 plate, and its placement within the first opening in the plate ensure that
 the secondary sealing device will always be in proper sealing engagement
 between the two body portions. These design features also insure that the
 secondary sealing device will never prevent the proper assembly of the
 tubing coupler. Finally the coupler can be assembled without the secondary
 sealing device and the plate and still function properly.

DETAILS OF INVENTION
 There is shown in FIGS. 1-3 a tubing coupler 10 in accordance with this
 invention. The tubing coupler 10 has a first body portion 11 for
 attachment to the end of a first tube (not shown) and a separate second
 body portion 13 for attachment to the end of a second tube (not shown).
 The first body portion 11 defines a first passageway 15 through itself and
 the second body portion 13 defines a second passageway 16 through itself.
 The end of the first tube can be fixed to the first body portion 11 of the
 coupler 10 adjacent to an outer end 17 of the first passageway 15 and the
 first tube would thus be in fluid communication with the first passageway
 15. The end of the second tube can be fixed to the second body portion 13
 of the coupler 10 adjacent to an outer end 18 of the second passageway 16
 and the second tube would thus be in fluid communication with the second
 passageway 16. The tubing coupler 10 is further comprised of a plate 19.
 When the tubing coupler 10 is in use, the first body portion 11, the second
 body portion 13, and the plate 19 are assembled together as a unit but can
 be disassembled to allow service of the system. A surface on the first
 body portion 11 other than one adjacent the outer end 17 of the first
 passageway 15, defines a first mating face 20 on the first body portion
 11. A surface on the second body portion 13 other than one adjacent the
 outer end 18 of the second passageway 16, defines a second mating face 21
 on the second body portion 13. When the coupler 10 is assembled the plate
 19 is positioned between the first mating face 20, and the second mating
 face 21. In the preferred embodiment, the first mating face 20 and the
 second mating face 21 have substantially the same profile which is
 continuous with no recesses or projections and the plate 19 has a
 thickness 39 which is substantially uniform throughout the plate 19. In
 the preferred embodiment an outer periphery 51 of the first body mating
 face 20, an outer periphery 52 of the plate 19, and an outer periphery 53
 of the second mating face 21, all have substantially the same shape. A
 tubing coupler 10 made according to these preferred specifications can be
 assembled without the plate 19, and still function properly.
 A pilot 22 projects from the first mating face 20 of the first body portion
 11. The first passageway 15 through the first body portion 11 extends
 through the pilot 22 and terminates at an opening 23 in the end 24 of the
 pilot 22. This opening 23 in the end 24 of the pilot 22 is disposed at an
 inner end 25 of the first passageway 15 opposite the outer end 17. An
 inner end 26 of the second passageway 16, which is opposite the outer end
 18, terminates at a first opening 27 in the second mating face 21 of the
 second body portion 13. The inner end 26 of the second passageway 16 of
 the second body portion 13, defines a cavity 28 similar in shape to and
 slightly larger than the pilot 22, which projects from the first mating
 face 20 of the first body portion 11. When the tubing coupler 10 is
 assembled, the pilot 22 is positioned within the cavity 28 defined by the
 inner end 26 of the second passageway 16. A small space 32 is, thus,
 defined concentrically between an outer surface 33 of the pilot 22 and an
 inner surface 34 of the cavity 28. Furthermore, the plate 19 defines a
 first opening 29 through itself of sufficient size that the pilot 22 can
 protrude through this first opening 29 in the plate 19. Thus, when the
 coupler 10 is correctly assembled the plate 19 is sandwiched between the
 first mating face 20 and the second mating face 21, and a periphery 30 of
 the first opening 29 in the plate 19 surrounds a portion of the pilot 22.
 Thus, when properly assembled and attached to the first tube 12 and the
 second tube 14 the tubing coupler 10 provides for fluid movement from the
 first tube 12 through the first passageway 15 through the second
 passageway 16 and into the second tube 14 and in the reverse direction.
 The tubing coupler 10 further includes one or more clamping devices 40 to
 urge the first body portion 11 toward the second body portion 13 and
 thereby maintain the tubing coupler 10 in an assembled state. In the
 preferred embodiment, the clamping forces applied by these one or more
 clamping devices 40 can be released from the coupler 10 so that the first
 body portion 11, the second body portion 13, and the plate 19 can be
 separated to allow service of the system. These one or more clamping
 devices 40 may be of any of a large number of designs. In one preferred
 embodiment the first body portion 11 defines a third passageway 41 which
 starts at an opening 42 in the first mating face 20 and extends into the
 first body portion 11. The second body portion 13 may define a fourth
 passageway 43 which starts at a second opening 44 in the second mating
 face 21 and extends into the second body portion 13. The plate 19 may
 define a second opening 45 in itself. The fourth passageway 43 would be
 positioned within the second body portion 13, such that when the tubing
 coupler 10 is assembled, the fourth passageway 43 aligns with the third
 passageway 41. Furthermore, the second opening 45 in the plate 19 would be
 positioned within the plate 19 such that when the tubing coupler 10 is
 assembled the second opening 45 in the plate 19 aligns with the third
 passageway 41. The one or more clamping devices 40 of the tubing coupler
 10 may be comprised of a member 46 which is disposed in the third
 passageway 41 and the fourth passageway 43, and protrudes through the
 second opening 45 in the plate 19 when the tubing coupler 10 is assembled.
 In the most preferred embodiment the one or more clamping devices 40 are
 comprised of a threaded stud 47 which is fixedly attached within the
 fourth passageway 43 and protrudes through the second opening 45 in the
 plate 19 and completely through and beyond the third passageway 41. A nut
 48 threadedly engages an outer portion 50 of the threaded stud 47 which
 extends beyond the third passageway 41. When this nut 48 is tightened, it
 acts to urge the first body portion 11 toward the second body portion 13
 and maintain the tubing coupler 10 in an assembled state.
 The tubing coupler 10 of the present invention has primary sealing means. A
 primary sealing device 31 circumscribes a portion of the outer surface 33
 of the pilot 22. This primary sealing device 31 is positioned at a
 distance from the first mating face 20 that is preferably greater than the
 thickness 39 of the plate 19. When the tubing coupler 10 is assembled, the
 primary sealing device 31 entirely fills a cross-section 35 (through
 section line 36) of the space 32 between the inner surface 34 of the
 cavity 28 and the outer surface 33 of the pilot 22 as is best shown in
 FIG. 4. The primary sealing device 31, thus, prevents fluid from traveling
 between the first passageway 15 or the second passageway 16 and the
 outside atmosphere. In the preferred embodiment, an annular groove 38 is
 present in the outer surface 33 of the pilot at a distance from the first
 mating face 20 which is greater than the thickness 39 of the plate 19.
 Also in the preferred embodiment the primary sealing device 31 is an
 O-ring sealing device and is positioned within the annular groove 38 in
 the outer surface 33 of the pilot 22.
 The tubing coupler 10 of the present invention also has secondary sealing
 means. A secondary sealing device 37 is positioned inside the periphery 30
 of the first opening 29 in the plate 19. The secondary sealing device may
 be made of any of a large number of materials. Preferably the secondary
 sealing device is made of a springy material such that it can be
 substantially elastically compressed. The secondary sealing device also
 has a thickness 49 that is preferably slightly greater than the thickness
 39 of the plate 19. In the preferred embodiment, the secondary sealing
 device 37 is made of HNBR rubber which is well known in the refrigeration
 equipment industry and is bonded to the periphery 30 of the first opening
 29 in the plate 19. When the tubing coupler 10 is assembled the secondary
 sealing device 37 surrounds both a portion of the outer surface 33 of the
 pilot 22 and the first opening 27 in the second mating face 21. When the
 tubing coupler 10 is assembled the secondary sealing device 37 is
 compressed between the first mating face 20 and the second mating face 21.
 Thus, the secondary sealing device 37 fills spaces between the first
 mating face 20, the plate 19, and the second mating face 21 through which
 fluid could otherwise travel. The secondary sealing device 37, therefore,
 prevents fluid from traveling between the first passageway 15 or the
 second passageway 16 and the outside atmosphere. The secondary sealing
 device 37 is included in the tubing coupler 10 as a backup for the primary
 sealing device 31 and is only relied on to seal the tubing coupler 10 in
 the event that the primary sealing device 31 should fail. As mentioned
 above, in the preferred embodiment, the first mating face 20 and the
 second mating face 21 have substantially the same profile which is
 continuous and free of recesses and projections and the plate 19 is of
 substantially uniform thickness 39. A tubing coupler 10 made according to
 these preferred specifications can be assembled without the plate 19 or
 the secondary sealing device 37 and still function properly provided the
 primary sealing device 31 does not fail.