Abstract:
A connector for a length of corrugated tubing. The connector includes a fitting including a passage therethrough, a clamping surface, a seal, and a nut operably connected to the fitting. The tubing is in fluid communication with the passage through the fitting. Axial movement of the nut towards the clamping surface-urges the tubing against the seal wherein the tubing is thereby sealingly restrained to the fitting and a clamping surface is formed capable of causing an end portion of the corrugated tube to form a flare by the end portion of the corrugated tube being compressed against the clamping surface and the seal and sealed thereagainst by the action of the nut.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a connector for use with corrugated tubing, and more specifically but not exclusively, to a connector including an 0-ring for sealing corrugated tubing to said connector. 
     Corrugated tubing is widely used as a conduit in the gas industry and it is a common requirement that such tubing is easily and hermetically attachable to a multitude of devices. As a result, many different forms of hermetically sealable connectors for use specifically with corrugated tubing exist, the desirable characteristics of which include ease of manufacture and assembly, and durability and maintainability of the seal during use. 
     An example of a connector for corrugated tubing is disclosed in EP 0 853 742 B1 which describes a fitting including a locating sleeve. The fitting is installed by cutting the tubing in a valley in the surface of the tubing and placing a nut over the tubing. Two split ring washers are placed in a valley adjacent to the cut end of the tubing to restrict movement of the nut. The body is aligned with the tubing by placing the locating sleeve connected to the body in the tubing. The nut engages threads on the body and as the nut is tightened, a tapered end of the body engages the cut end of the tubing and flares the cut end of the tubing. The fitting makes a flared metal-to-metal seal by folding the convolutions of the tubing back against itself creating a double flare without the need for flaring or flattening tools. In the context of this technical field, the term flaring and derivatives thereof refers to the action of an end of a corrugated tube being urged against a clamping face, said face tapering radially outward and in a direction forward of said tubing such that at least one tubing corrugation collapses axially and said tube end is urged and then subsequently clamped interiorly of said tube. 
     A further example of prior art in this field is U.S. Pat. No. 4,674,775 which describes a coupling for a corrugated conduit including a main tubular body with a sleeve defining a conduit receiving bore terminating at its inner end in an annular shoulder projecting radially inwardly of the tubular body. A nipple clamps the end portion of the conduit and, upon rotation of a nut, said nipple is pressed forwardly forcing the conduit into the shoulder at which point corrugations left projecting beyond the nipple are collapsed between the forward end of the nipple and the shoulder. At the juncture of the shoulder and the conduit is an annular groove receiving a sealing ring for improving the sealing effect between the shoulder and the conduit end. 
     A disadvantage of EP 0 853 742 B1 lies in the reliance on the integrity and durability of just a flared metal-to-metal seal. A disadvantage of U.S. Pat. No. 4,674,775 lies in the reliance on the sealing qualities of a non-flared metal-to-metal seal. 
     BRIEF SUMMARY OF THE INVENTION 
     According to a first embodiment of the present invention, there is provided a connector assembly for a length of corrugated tubing, the connector assembly comprising: 
     a fitting including a passage; 
     a clamping surface; 
     a seal; 
     and an axial loading means operably connected to the fitting, 
     wherein, in use, a corrugated tube is in fluid communication with said passage of said fitting and wherein axial movement of said loading means towards said clamping surface urges said tubing against said clamping surface and against said seal wherein said tubing is thereby sealingly restrained to said connector fitting; and 
     wherein the clamping surface is formed such that, in use, it is capable of causing an end portion of a corrugated tube to form a flare by said end portion being compressed against said clamping surface and against said seal and sealed thereagainst under the action of the loading means. 
     Up until now it has been thought enough to rely on either a double flare as the mechanism by which connectors of this type are sealed or no double flare but the collapsing of tubing corrugations combined with an annular sealing means such as an elastomeric 0-ring or gasket. A connector assembly in accordance with the invention has the advantage that the strength and durability of a double flare connection between a tube and a connector is greatly enhanced when allied with the sealing qualities of a seal. Furthermore, the provision of two effective sealing means (the double flare connection and the seal) has the advantage that the connector of the present invention is not as reliant as the prior art on high quality manufactured parts with minimal surface imperfections in order to form an effective seal, thus making the connector of the present invention quick and cheap to manufacture. 
     In addition to this, known double flare connectors rely on the creation of said double flare in order to achieve a seal. The creation of the flare, though, is reliant on a user cutting a corrugated tube in the correct position and inserting a loading means around said tube correctly so as to leave a convolution of said corrugated tube free to be compressed when said tubing is connected to the fitting. The provision of the seal, for example in the form of an 0-ring, in the connector of the present invention enables a substantially hermetic seal to be created even when a flare is not formed within the connector, for example, due to incorrect positioning of the loading means, incorrect cutting of the tubing, or a failure in the material of the corrugated tube. The connector of the present invention is not as reliant on the user in order to function. 
     Furthermore, the fitting can be inexpensively maintained by regularly replacing said seal before it is considered overly worn. 
     As disclosed in the introduction, the term ‘to flare’ and any derivative thereof refers to the action of an end of a corrugated tube being urged against a clamping face, said face tapering radially outward and in a direction forward of said tubing such that at least one tubing corrugation collapses axially and said tube end is urged and then subsequently clamped interiorly of said tube. The folded portion of said corrugated tubing is referred to as a flare. 
     Flaring can also refer to the collapsed, concertina-like folding of more than one convolution of corrugated tubing against a tapered clamping face to form multiple folded portions. The strength and durability of the connection between the tube and the connector is, therefore, further enhanced by also including the sealing qualities of a flared metal-to-metal connection. A hermetic seal can be achieved by using both a flared metal-to-metal connection in conjunction with a compressed seal. Preferably, the seal is an 0-ring and, further preferably, is made from resilient material which may be an elastomeric material. The seal may be annular and have any suitable cross section, for example circular, square, rectangular and/or be grooved or ribbed. 
     The axial loading means, preferably, comprises a collet which, in use, engages at least one convolution of a corrugated tube. The collet is an element which may be shaped to surround the corrugated tubing and to engage with the corrugations such that one element moves with the other. Preferably, the axial loading means further comprises a nut, advantageously said nut engages the collet such that movement of a corrugated tube relative to the loading means is restricted by the position of the nut. Axial movement of the loading means towards the clamping surface preferably urges a corrugated tube towards said clamping surface. 
     Before assembly, the tubing may advantageously be cut in a valley in the corrugated surface. The clamping surface preferably opposes an end face of the loading means and, in use, said end face matingly engages with said clamping surface. Advantageously, said end face and said clamping surface may define an oblique angle in relation to the axial movement direction of said loading means. As such, a folded surface of the corrugated tube end can be brought flush into contact with the clamping surface and can be compressed evenly between said surface and the end face of the collet so as to be securely restrained therebetween and to create a sealing engagement with the opposing clamping surfaces. 
     Preferably, an annular collar with a frusto-conical surface which tapers radially outward forms the clamping surface. Advantageously, said clamping surface forms a shoulder against which, in use, a corrugated tube abuts. This prevents a corrugated tube from travelling internally through said passage. Accordingly, a tube is, in use, compressed against the shoulder to flare against the clamping surface when the loading means is advanced towards the fitting. Preferably, the diameter of the leading edge of the frusto-conical surface is smaller than the internal diameter of the tubing such that the tubing is thereby prevented from being urged past and internally through the passage. 
     Preferably, the seal is closely pressfittingly received by the fitting and is secured in place by virtue of its close tolerance fit therewith. 
     Advantageously, the seal is positioned exteriorly of the fitting passageway, i.e. the seal is not positioned interiorly in the fitting passageway and no part of it protrudes into the fitting passageway, thus maximising the diameter of the fitting passageway. 
     In one embodiment of the invention, the seal may comprise a frusto-conical surface which tapers radially outwardly so as to engage with the clamping surface by virtue of its congruent shape. The connector may further comprise an end face which extends radially outwardly from the clamping surface and the seal may comprise a rim which extends radially outwardly so as to engage with said end face. Preferably, the seal is sized so as to, in use, engage with substantially all the clamping surface and end face such that there are no voids or gaps, thus enabling a hermetic seal between the fitting and the tube. The seal is, preferably, made of a malleable material such as copper. 
     In another embodiment of the invention, a recess such as an annular groove or the like may press-fittingly receive the seal. Advantageously, the recess is sized and configured to contain the seal when, in use, it is compressed by the loading means. Advantageously, the seal does not protrude from the recess when the connector is fully tightened. This allows a surface of a corrugated tube end to contact the clamping surface without any voids or gaps, thus enabling a hermetic seal. Furthermore, the seal may be press-fittingly received by the recess. Such a friction tight fit prevents the seal from falling out of the connector prior to assembly with a corrugated tube. The seal may also be easily replaced when worn, thus greatly improving the life of the connector assembly and making said assembly cheaper to maintain. 
     Preferably, the seal has a diameter substantially equal to the exterior diameter of a corrugated tube at the apex of a corrugation. 
     The collet, advantageously, includes at least one bevelled ridge capable of matingly engaging with at least one corrugation of a corrugated tube. The at least one bevelled ridge preferably opposes the clamping surface of the fitting. Advantageously, the collet comprises two or three or more bevelled ridges. Engagement of the collet with the tubing may be such that there is a close tolerance fit. 
     Each bevelled ridge may have a pitch and profile substantially equal to the pitch and profile of the corrugations of a corrugated tube. This enables the collet to mate securely with a corrugated tube such that said tubing cannot move significantly in relation to the collet. The proximal and distal end faces of the collet, preferably, have the same profile such that the collet can be oriented with either of its ends proximate to the clamping surface of the fitting. 
     Advantageously, the collet and nut that comprise the axial loading means are two separate parts, but it will be understood that they could, for ease of assembly, be formed as one part. The nut is preferably a flanged nut and, further advantageously, the collet is formed of two semi-circular rings, thus enabling it to be secured in position around either side of the corrugated tubing. 
     In a further embodiment of the invention the proximal and distal end faces of the collet are perpendicular to the longitudinal axis of the fitting. In another embodiment of the present invention the collet includes a shoulder for, in use, engaging with the nut. Preferably, a first shoulder is located at the proximal end and a second shoulder is located at the distal end of the collet enabling said collet to be reversible such that it can be placed on the tubing either way round. This ensures that provision of a shoulder on the collet does not complicate the installation of the connector assembly. The shoulder is, preferably, in the form of an L-shaped cut out in the end faces of the collet. In use, the shoulder proximate to the clamping surface of the fitting may provide a void in the fitting into which the tube can extend when flaring. This reduces any bunching of corrugated tube within the fitting, thus enabling the collet to press evenly over the surface of said tubing which improves the integrity of the seal between a corrugated tube, the collet and the connector. 
     According to a further aspect of the invention, there is provided a method for securing a connector assembly to a corrugated tube, comprising the steps of: 
     a) providing a connector assembly and a corrugated tube, the connector assembly comprising a fitting including a passage, a clamping surface, a seal, and an axial loading means, 
     b) cutting said corrugated tube in a valley in the corrugated surface to form a cut end, 
     c) placing said axial loading means over said tubing, 
     d) engaging said cut end of the tubing with said clamping surface, 
     e) operably connecting said axial loading means to said fitting, 
     f) applying a load to said axial loading means such that said corrugated tube is driven into contact with said clamping surface and said cut end is urged axially to create a flare which is compressed against said clamping surface and against said seal such that said corrugated tube is thereby sealingly restrained to said fitting. 
     According to another aspect of the invention, there is provided a method for securing a connector assembly to a corrugated tube, comprising the steps of: 
     a) providing a corrugated tube and a connector according to the present invention, 
     b) cutting said corrugated tube in a valley in the corrugated surface to form a cut end, 
     c) placing said axial loading means over said corrugated tubing, 
     d) engaging the cut end of the tubing with said clamping surface, 
     e) operably connecting said axial loading means to said fitting, 
     f) applying a load to said axial loading means such that said corrugated tube is driven into contact with said clamping surface and said cut end is urged axially to create a flare which is compressed against said clamping surface and against said seal such that said corrugated tube is thereby sealingly restrained to said fitting. 
     Preferably, the method for securing a connector assembly to a corrugated tube further includes the step of placing a collet in the first complete valley adjacent to the cut end of the tubing and, further advantageously, engaging the collet with the axial loading means. 
     It will be apparent to those skilled in the art that the connector assembly of the present invention could be attached to metal or plastic corrugated tubing or other types of tubing. The connector assembly may, for example, be used with stainless steel corrugated tubing or with more ductile metal tubing such as copper tubing. The tubing could be made from any suitable material and could have ridges or other such engageable means only at the cut end rather than corrugations along the length of the tubing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order that the invention may be more readily understood, reference will now be made, by way of example, to  FIGS. 1 to 6 , in which: 
         FIG. 1( a )  is a perspective, partial cut-away view of a connector assembly according to a first embodiment of the present invention showing a nut in a first position; 
         FIG. 1( b )  is a plan, partial cut-away view of the connector assembly of  FIG. 1( a ) ; 
         FIG. 2( a )  is a perspective, partial cut-away view of the connector assembly according to a first embodiment of the present invention showing the nut in a second position; 
         FIG. 2( b )  is a plan, partial cut-away view of the connector assembly of  FIG. 2( a ) ; 
         FIG. 3( a )  is an enlarged view of a portion of  FIG. 1( b ) ; 
         FIG. 3( b )  is an enlarged view of a portion of  FIG. 2( b ) ; 
         FIG. 4( a )  is a detailed view of a portion of the connector assembly according to a second embodiment of the present invention showing the nut in a first position; 
         FIG. 4( b )  is a detailed view of a portion of the connector assembly according to a second embodiment of the present invention showing the nut in a second position; 
         FIG. 5( a )  is a perspective, partial cut-away view of the connector assembly according to a second embodiment of the present invention showing the nut in a second position; 
         FIG. 5( b )  is a plan, partial cut-away view of the connector assembly of  FIG. 5( a ) ; 
         FIG. 6( a )  is an enlarged view of a portion of  FIG. 4( b ) ; 
         FIG. 6( b )  is an enlarged view of a portion of  FIG. 5( b ) ; 
         FIG. 7( a )  is detailed view of a portion of the connector assembly according to a third embodiment of the present invention showing the nut in a first position; and 
         FIG. 7( b )  is a detailed view of a portion of the connector assembly according to a third embodiment of the present invention showing the nut in a second position. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A first embodiment of the invention will now be described with reference to  FIGS. 1 to 3 . Referring firstly to  FIGS. 1( a ) and 1( b ) , a predominantly cylindrical connector assembly  100  is shown which, in use, is connected at one end to a corrugated stainless steel tube  101  and at the other end to an apparatus (not shown). The connection between the tubing and the connector is substantially hermetic and will be described in more detail below. 
     References to the tubing  101  are references to the connector assembly  100  when in use. 
     The connector assembly  100  comprises a fitting  102 , an axial loading nut  103 , a collet  104 , a seal in the form of an elastomeric 0-ring  105  and a clamping surface  107 . As used herein, the term “proximal” refers to a point, location, end or the like which, in use, is closest to the clamping surface  107 . The term “distal” refers to a point, location, end or the like which, in use, is furthest from the clamping surface  107 . The fitting  102  is cannular, with a through passage  111 , a proximal portion of which forms a tubing aperture having an internal diameter, at the proximal end, approximately equal to the exterior diameter of the corrugated tubing  101  and with a threaded exterior; the distal end of the fitting  102  having a threaded interior. 
     Together, the nut  103  and the collet  104  form a loading means. 
     In preparation for attachment of the connector assembly  100  to the tubing  101 , the tubing  101  is cut in a valley in the corrugated surface. Following this, in use, the tubing  101  is received by the fitting  102  to form a single conduit with the passage by urging the fitting  102  over and around the cut end of the corrugated tubing  101 . The tubing  101  and fitting  102  are then retained together by provision of the nut  103  and collet  104  wherein the collet  104  is positioned in a valley on the outer surface of the corrugated tubing  101  and the nut  103  engages both a distal face  106  of said collet  104  and the threaded exterior of the fitting  102 . Each component of the assembly  100  is described in greater detail below. 
     The method for connecting the connector assembly  100  to the tubing  101  is as follows: 
     The tubing  101  is cut, for example using a pipe cutter, in a valley in the corrugated surface of the tubing  101 . The nut  103  is then placed over the tubing  101  and the collet  104  is placed in the first complete valley adjacent to the cut end. The tubing  101  is then received in the proximal end of the fitting  102  so as to be in fluid communication with the passage  111  through the fitting  102  and the nut  103  is tightened onto the threaded exterior of said fitting  102 . 
     As the nut  103  is tightened said nut  103  engages with the distal face  106  of the collet  104 . Further axial movement of the nut  103  towards the fitting  102  urges the collet  104  and, in turn, the tubing  101 , towards the clamping surface  107  located on the interior walls of the fitting  102 . The clamping surface  107  tapers radially outward and is configured such that continued tightening of the nut  103  urges the cut end of the tubing  101  to collapse axially such that the cut end of the tubing folds concertina-like against an adjacent convolution of corrugated tubing  101  to form a folded portion as it is driven against the clamping surface  107  of the fitting  102 . The tube end is subsequently positioned interiorly of said tube thus creating a compressed corrugation referred to in the art as a double-walled flare. The flare is brought into engagement with the 0-ring  105  positioned on the clamping surface  107  of the fitting  102  as the nut  103  is tightened to its fullest extent. A hermetic seal is formed as the flare is compressed against the clamping surface  107  and 0-ring  105  by a proximal face  108  of the collet  104  which opposes the clamping surface  107 . The combination of the flared metal-to-metal connection allied with the 0-ring  105  creates a seal which is more reliable and durable than joins achieved by known corrugated tube connectors.  FIGS. 2 ( a )  and  2  ( b ) show the connector assembly  100  fastened to the corrugated tubing  101 . 
     It will be apparent that the position of the collet  104  determines whether the flare is double-walled. If the collet  104  is placed in the first complete valley of the corrugated tubing adjacent to the cut end then a double-walled flare can be created. If the collet is placed in a corrugation or corrugations forward of this point, i.e. in the direction of the fitting, then no folding of the corrugations can be achieved. If the collet is placed in a corrugation or corrugations away from this point, i.e. further from the fitting, then, in use, more than one corrugation may be collapsed. 
       FIGS. 3( a ) and ( b )  are enlarged views of the connector assembly  100  and show the folding and compression of the cut end of the tubing  101  against the clamping surface  107  and 0-ring  105  to create the flare, described above in detail. The collet  104  is of the form of two semi-circular rings with a first and second half fitting around and on either side of the tubing  101 . The collet  104  includes three radially interiorly facing bevelled ridges; one forming the distal face  106  at one end, one forming the proximal face  108  at the opposite end and one positioned therebetween. In use, the proximal face  108  co-ordinates with the clamping surface  107  to provide opposing surfaces between which the corrugated tube  101  is compressed. Each bevelled ridge is sized and positioned so as to be received into adjacent corrugations of the tubing  101 . 
     A flat end face  112  extends radially outward from the proximal face  108  and perpendicular to the longitudinal axis of the fitting  102 . This end face  112  opposes a fitting end face  113  which extends radially outward from the clamping surface  107  and also perpendicular to the longitudinal axis of the fitting  102 . An annular recess  110  for press-fittingly receiving the 0-ring  105  is located in the fitting end face  113 . A second end face  114  extends radially outward from the distal face  106  and perpendicular to the longitudinal axis of the fitting  102  such that the collet  104  can be used with either the first or second end face  112 ,  114  proximate to the clamping surface  107 . 
     The nut  103  is of the form of a locking nut with a flange  109  at the distal end and an interiorly threaded portion at the proximal end. The flange  109  has a smaller internal diameter than the internal diameter of the threaded portion of the nut  103  and approximately equal to the exterior diameter of the tubing  101  at the apex of a corrugation. 
     The second end face  114  extending from the distal face  106  of the collet  104  engages the flange  109  such that when the nut  103  is tightened (i.e. the nut is rotated, causing it to move proximally) said flange  109  is driven into abutment with the collet  104  thus preventing distal movement of said collet  104  and, in turn, the corrugated tubing  101 , and urging said collet  104  and tubing  101  proximally, towards the clamping surface  107  of the connector fitting  102 . A similar profile on the proximal end of the collet  104  means the collet  104  is reversible. This enables it to be placed on the tubing either way round, therefore simplifying installation of the connector assembly  100 . 
     The profile of the clamping surface  107  of the first embodiment can be seen most clearly in  FIGS. 3( a ) and 3( b ) . The clamping surface  107  defines a frusto-conical surface which tapers radially outwardly in a direction toward the distal end of the fitting  102 . The face of the clamping surface  107  opposes and may abut the proximal face  108  of the collet  104  and tapers so as to matingly engage with said face  108 . The clamping surface  107  adjoins an annular collar portion which is raised in relation to the clamping surface in a direction extending radially into the passage  111 . This annular collar has a smaller diameter than the diameter of the tubing  101  at the cut end. It, therefore, forms a shoulder in the passage  111  against which the inserted tubing  101  abuts. In use, the tubing  101  is prevented from travelling past so is compressed against the clamping surface  107  when the nut  103  is tightened. The shoulder against which the tubing  101  abuts extends radially perpendicularly to the wall of the passage  111 . 
       FIGS. 3( a ) and 3( b )  also best show the exterior profile of the bevelled ridges of the collet  104 . Each bevel has a pitch and profile which closely matches the pitch and profile of the tubing corrugations and is sized such that each bevel can receiveably locate in a trough of a corrugation and is closely press-fittingly received therein thus limiting the axial movement of said tubing  101 . 
     The 0-ring  105  has a diameter approximately equal to the exterior diameter of the tubing  101  at the apex of a corrugation and is press-fittingly secured in the recess  110  in the fitting end face  113 . The 0-ring  105  remains in place when the corrugated tubing  101  is not pressed thereagainst but is also removable such that it can be replaced when worn. The recess  110  is sized so as to contain the 0-ring  105  when, in use, it is under compression from the folded tubing  101 . As such, in use, the 0-ring does not force the surface of the folded tubing  101  apart from the clamping surface  107  but is compressed to fill any voids therebetween. The 0-ring  105  is of the form of a toroid with circular cross section. Also, the collet  104  is sized such that when, in use, the nut  103  is tightened to its fullest extent and the flared corrugated tubing  101  is clamped between the proximal face  108  of said collet  104  and the clamping surface  107  the proximal end face  112  and opposing fitting end face  113  are spaced apart. This spacing provides a void in the fitting  102  into which the tube  101  can extend when flaring. This reduces any bunching of the tubing  101  within the connector fitting  102  and enables the collet  104  to press evenly over the surface of the folded portion of the corrugated tubing  101  and against the clamping surface  107  which improves the integrity of the seal therebetween. 
       FIGS. 4, 5 and 6  illustrate a second embodiment of the invention. In this embodiment the collet  104  further includes a cut-out portion in both the proximal and distal end faces  112 ,  114 . The cut-out portion on the distal end face  114  of the collet  104  creates an L-shaped annular groove or shoulder; the axial face of which, in use, engages the radially interior face of the flange  109  such that when the nut  103  is tightened (i.e. the nut  103  is rotated, causing it to move proximally) said flange  109  locates with the axial and longitudinal faces of the L-shaped groove or shoulder, thus preventing distal movement of the collet  104  and, in turn, the corrugated tubing  101 , and urging said collet  104  and tubing  101  proximally, towards the clamping surface  107  of the connector fitting  102 . A similar cut-out on the proximal end face  112  of the collet  104  means the collet  104  is reversible. As in the first embodiment, this enables the collet  104  to be placed on the tubing  101  either way round, therefore simplifying installation of the connector assembly  100 . Furthermore, the cut-out, or L-shaped groove proximate to the cut end of the corrugated tubing  101  provides a void in the fitting  102  into which the tube  101  can extend when flaring. This, as in the first embodiment, reduces any bunching of the tubing  101  within the connector fitting  102  and enables the collet  104  to press evenly over the surface of the folded portion of the corrugated tubing  101  and against the clamping surface  107  which improves the integrity of the seal therebetween. 
       FIG. 7  illustrates a third embodiment of the invention. In this embodiment the fitting  102  does not comprise an 0-ring  105  in a recess  110  located in the fitting end face  113 , rather the tubing  101  is hermetically sealed against a copper gasket  120  provided on the clamping surface  107  and said fitting end face  113 . 
     The gasket  120  is an annulus comprised of a frusto-conical portion  121  and a rim  122 . The frusto-conical portion  121  is sized so as to engage with substantially all the tapered clamping surface  107  and the rim  122  extends radially outward from said frusto-conical portion  121  so as to engage with substantially all the fitting end face  113  of the fitting  102 . 
     The gasket  120  is sized so as to be closely pressfittingly received by the tapered clamping surface  107  and end face  113 . An interior face  123  of the fitting  102  extends from the radially outermost end of the fitting end face  113  and parallel to the longitudinal axis of the fitting  102  toward the tube  101 , collet  104  and nut  103 . The gasket  120  is removably held in place by virtue of its frictionally engaging close tolerance fit with the interior face  123 . 
     The frictional engagement of the gasket  120  enables it to be held in position adjacent the clamping surface  107  and end face  113  without fastening the collet  104  proximate to the fitting  102 , such as, for example, during assembly and transport, etc. 
     As shown in  FIG. 7( b ) , fastening the collet  104  proximate to the fitting  102  also acts to secure said gasket  120  to the fitting  102 . 
     As with the previous two embodiments, the clamping surface  107  tapers radially outward and is configured such that continued tightening of the nut  103  urges the cut end of the tubing  101  to collapse axially such that the cut end of the tubing folds concertina-like against an adjacent convolution of corrugated tubing  101  to form a folded portion as it is driven against the clamping surface  107  of the fitting  102 . The tube end is subsequently positioned interiorly of said tube to create, as previously described, a double-walled flare. The flare is brought into engagement with the gasket  120  positioned on the clamping surface  107  and fitting end face  113  of the fitting  102  as the nut  103  is tightened to its fullest extent. A hermetic seal is formed as the flare is compressed against the gasket  120  by the proximal face  108  of the collet  104  which opposes the clamping surface  107  and fitting end face  113 . The combination of the flared metal-to-metal connection allied with the gasket  120  creates a seal which is more reliable and durable than joins achieved by known corrugated tube connectors. 
     The gasket is made of copper. The malleable nature of copper further enables a hermetic seal between the corrugated tubing  101  and the fitting  102 . 
     The present invention is not limited to the specific embodiments described above as it will be apparent to a reader skilled in the art that many forms of corrugated tubing connector assembly  100  could be formed that utilise a flared metal-to-metal connection in conjunction with an 0-ring  105  or a gasket  120  and a reversible collet  104 . Furthermore, it will be apparent that the connector  100  could be adapted for use with non-corrugated tubing as long as the collet  104  could engage with said tubing, for example, via the provision of a ridge or the like. The connector assembly  100  could be an end assembly, for example, to add rigidity to a hose end. Alternative arrangements and suitable materials will also be apparent to a reader skilled in the art.