This invention relates to a connector.

Connectors are well known in the field of fluid transfer systems, and may be used to connect two or more components of the fluid transfer system. For example, a connector might be used to connect two lengths of conduit (such as flexible tubing), or to connect a length of conduit to a piece of equipment, or even to directly connect two adjacent pieces of equipment. Similar systems are known for the protection of cables (such as electrical wires) between pieces of equipment, such as for example to prevent ingress of dirt and/or moisture. Such systems are described herein as 'conduit systems', although it will be understood that the presence of flexible conduit is not necessarily required.

Different connection types are known according to the components to be attached to the connector. Where a connection is to be made to a conduit, the connection may be made by means of a compression fitting. An internally-threaded nut is slipped over the end of the conduit, before the open conduit end is forced onto a spigot on the connector. The internally-threaded nut is then screwed onto an externally-threaded portion adjacent to the spigot. As the nut is tightened, the conduit end is clamped between the nut and the spigot, preventing accidental disconnection of the conduit or ingress or egress of fluid. When connection is to be made to a piece of equipment, the connection may be made by means of corresponding internally- and externally- threaded portions on the connector and equipment. Typically, an externally-threaded portion of the connector is screwed into an internally-threaded socket on the equipment. Again, this provides a secure and leak-proof connection.

Specialised connectors are known which provide additional benefits, useful where the conduit system creates additional requirements. For example, one type of connector is known as a swivel connector. Swivel connectors are especially useful when connecting components to fixed or heavy items, such as equipment. As described above, this typically involves screwing an externally-threaded portion of a connector into a socket on the equipment, which on a fixed connector would necessitate rotation of the connector. If another end of the connector is already connected to a component, whether a conduit or a second piece of equipment, such rotation could be undesirable W

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(because for example it would cause twisting in the conduit) or impossible (because for example the second piece of equipment is heavy or is fixed to a surface). Thus, a swivel connector provides at least two parts which are able to rotate relative to one another along a longitudinal axis. Each connection to a component of the conduit system is located on a different part of the connector, so that the rotation of one part (for example, to screw the connector into a threaded socket on a piece of equipment) will not affect other parts of the connector, or connected components.

Swivel fittings typically consist of complementary male and female parts, with an O-ring between the two to seal the joint against ingress or egress of material, such as ingress of moisture and/or dirt, or leakage of fluid from within the conduit system (whilst still allowing rotation as above). The connectors may also contain a spring steel clip (such as a circlip) to prevent separation of the male and female parts. Such connectors can be unsuitable for use in environments where it is essential to maintain electrical continuity between the different components, such as where it is necessary to ground the entire conduit system to earth. The O-ring (or other seal) which allows the parts to the connector to rotate relative to one another, whilst preventing leakage, also physically separates the two components. Since the polymeric materials typically used as seals are also electrical insulators, the separation of the connector parts prevents the formation of a continuous electrical connection between the connected components. Similarly, the spring steel circlip used in the swivel fitting is a poor electrical conductor, and so does not particularly improve the electrical continuity between the connected components There is therefore a need for an improved connector for use in conduit systems.

According to the present invention there is provided a connector for connecting a first component to a second component in a conduit system, comprising a first part for connection to a first component, a second part for connection to a second component, and a sealing member for forming a seal between the first part and the second part such that the first part and second part can be rotated relative to one another about a generally longitudinal axis, the connector having a central opening therethrough; characterised in that the connector further comprises a substantially annular, electrically conductive, resiliently compressible member around the generally longitudinal axis and between and in electrical contact with both the first and second parts.

It will be understood that the generally longitudinal axis lies substantially along the mean direction of the central opening at the interface between the first and second parts.

The inventor has surprisingly found that the use of an electrically conductive resiliently compressible member between and in electrical contact with both the first and second parts can ensure that electrical continuity between the first and second parts is maintained without compromising the ability of the sealing member to form a fluid seal between the first and second parts. It has further been found that the use of a substantially annular electrically conductive resiliently compressible member surrounding the generally longitudinal axis ensures that this electrical continuity is maintained without affecting the ability of the first part and second part to rotate relative to one another. The invention also allows for the production of a connector having high mechanical strength, high protection against ingress of water, and high electrical continuity. In some embodiments, the substantially annular electrically conductive resiliently compressible member comprises a non-planar washer. For example, the substantially annular electrically conductive resiliently compressible member may comprise a wavy (or crinkle) washer. Alternatively or additionally, the substantially annular electrically conductive resiliently compressible member may comprise a spring washer.

In some embodiments, the substantially annular electrically conductive resiliently compressible member comprises an open-coil helical spring.

In some embodiments, the substantially annular electrically conductive resiliently compressible member comprises metal brushes.

It will be understood that the substantially annular electrically conductive resiliently compressible member need not completely enclose the generally longitudinal axis, provided that, for all possible relative orientations of the first part and second parts, the substantially annular electrically conductive resiliently compressible member is in electrical contact with both the first and second parts. However, in general, the substantially annular electrically conductive resiliently compressible member will contact the first and second parts at a plurality of points distributed around the longitudinal axis, and hence must extend the majority of the way around the generally longitudinal axis. This ensures that the forces acting on the first and second parts as a result of compression of the substantially annular electrically conductive resiliently compressible member are distributed evenly around the generally longitudinal axis, and hence that the possibility of disruption of the sealing activity of the sealing member is reduced.

In some embodiments, the substantially annular electrically conductive resiliently compressible member is positioned between radially outer regions of the first and second parts. For example, the substantially annular electrically conductive resiliently compressible member may be located at the outer surface of the connector. In such embodiments, the substantially annular electrically conductive resiliently compressible member provides a visual indication of the electrical continuity extending across the connector. In some embodiments, the substantially annular electrically conductive resiliently compressible member is positioned between radially inner regions of the first and second parts. For example, the substantially annular electrically conductive resiliently compressible member may be located in the surface surrounding the central opening through the connector. In such embodiments, the substantially annular electrically conductive resiliently compressible member is protected from exposure to the environment outside the connector, and hence from corrosion which might impede the electrical continuity.

In some embodiments, the first part comprises a male portion and the second part comprises a female portion for receiving the male portion, the interface between the male and female portions defining the generally longitudinal axis.

In some embodiments, the sealing member is in the form of a resiliently compressible ring. Typically, the sealing member will be non-electrically conductive. For example, the sealing member may take the form of an O-ring made from rubber or any other suitable natural or synthetic polymer.

In some embodiments, at least one of the first and second parts comprises an externally threaded portion for connection to a component having a corresponding internally threaded portion. For example, equipment forming part of a conduit system may have an internally threaded opening into which the externally threaded portion of the connector can be screwed. The connector can therefore be used to connect the equipment to other components of the conduit system.

In some embodiments, at least one of the first and second parts comprises a compression fitting for connection to a conduit. For example, the compression fitting may be used to connect flexible conduit to other components of the conduit system. In some further embodiments, the compression fitting comprises a compression seal comprising an annular trunk having a first end, a second end and an outwardly bulbous section therebetween; a sealing surface provided on an outer portion of said bulbous section; and wherein a resiliently deformable element is provided at or adjacent the first end of the trunk. Suitable compression seals are disclosed in European Patent Application No. 10251233.2.

An embodiment of the invention is described with reference to the accompanying Figures, in which:

Figure 1 shows a prior art connector, in assembled (a) and disassembled (b) states; and

Figure 2 shows an embodiment of a connector according to the invention, in assembled (a) and disassembled (b) states.

Referring to Figure 1, a prior art connector 10 is generally cylindrical, and has a first part 12 at a first end 14 comprising a compression fitting for connection to a conduit, and a second part 16 at a second end 18 comprising an externally threaded portion for connection to a component having a corresponding internally threaded portion.

As shown in Figure 1 (b), the first part 12 comprises a nut 20, a compression seal 30, a conduit insert 40 and a fitting body 50. The nut 20 is internally threaded 22 in the usual manner, and has six hexagonally- arranged flattened portions 24 around the external circumference, to facilitate gripping of the nut by hand tools during operation. The distal face of the nut (relative to the connector 10) is provided with an inner flange 26 around the central opening of the nut 20, to prevent the loss of connector parts from the assembled connector, whilst also allowing a connected conduit to pass through the nut.

The compression seal 30 comprises an annular trunk 32 having a proximal end 33, a distal end 34 and an outwardly bulbous section 35 therebetween. A sealing surface 36 is provided on an outer portion of the bulbous section 35. A resiliently deformable element 37 is provided adjacent the proximal end 33 of the trunk 32. In this particular embodiment, the resiliently deformable element 37 comprises six axial crenellations distributed evenly around the circumference of the proximal end 33.

The conduit insert 40 comprises a cylindrical tubular trunk 42 having a proximal end 43 and a distal end 44. The outer surface of the trunk 42 is provided with a single turn of a helical ridge 45 adjacent to the distal end 44. The proximal end 43 of the conduit insert 40 is provided with an externally-projecting radial flange 46. The flange 46 joins with an annular collar 47 projecting distally from the proximal end to define an annular channel (not shown) between the collar 47 and the trunk 42. The outer circumferential surface of the collar 47 is provided with a continuous series of longitudinal ridges 48.

The fitting body 50 has a distal portion 52, a proximal portion 54, and a mid portion 56. The mid portion 56 has six hexagonally-arranged flattened portions 57 around the external circumference, to facilitate gripping of the nut by hand tools during operation. The distal portion 52 is provided with an external thread 53 corresponding to the internal thread 21 of nut 20. The proximal portion 54 is cylindrical and has two circumferential grooves 55 in the outer surface thereof. The diameter of the distal portion 52 is greater than that of the proximal portion 54, whilst the diameter of the mid portion 56 is greater still. A central channel (not shown) passes through the fitting body 50, and has a wider diameter within the distal portion 52 to receive the annular collar The second part 16 comprises a fitting body 60 having a cylindrical tubular proximal portion 62, an externally threaded distal portion 64, and a mid portion 66. The mid portion 66 has six hexagonally-arranged flattened portions 68 around the external circumference, to facilitate gripping of the nut by hand tools during operation. The internal surface of the proximal portion 62 has a circumferential groove 63 therein.

The compression seal 30 is formed from polyamide. Other polymeric materials could alternatively be used. The remaining parts are made from stainless steel. In use, a rubber O-ring 70 is placed in the distal circumferential groove 55a of the fitting body 50 of the first part 12 of the connector 10, and a spring steel circlip 72 is placed in the proximal circumferential groove 55b. The proximal portion 54 of the first part fitting body 50 is then inserted into the proximal portion 62 of the second part fitting body 60, such that the circlip 72 is received in the internal circumferential groove 63 of the second part fitting body 60, and the O-ring 70 forms a seal between the first part fitting body 50 and the second part fitting body 60. The engagement of the circlip 72 with the two parts allows the first part and the second part to rotate relative to one another along a common axis, whilst preventing longitudinal separation. The distal portion 64 of the second part fitting body 60 may be screwed into an internally threaded socket, such as on a piece of equipment. As a result of the construction of the connector 10, having first 12 and second 16 parts with the O-ring 70 forming a seal between the two, the second part 16 can be screwed into an internally threaded socket without affecting the orientation of the first part 12.

The first part 12 may be used for connection to a conduit, such as flexible conduit. The nut 20 and compression seal 30 are placed over the end of the tubing, which is then forced over the distal end 44 of the conduit insert 40. The proximal end 43 of the conduit insert 40 is then inserted into the distal portion 52 of the first part fitting body 50, the compression seal 30 is slid along the tubing so that it is adjacent to the first part fitting body 50, and the nut 20 is then screwed on to the external thread 53 of the distal portion 52 of the fitting body 50. In this way, the compression seal 30 is compressed around the tubing, ensuring that the tubing forms a tight seal around the conduit insert 40. Again, the construction of the connector 10 prevents tightening of the nut 20 against the first part fitting body 50 from rotating the second part 16, and hence from overtightening the connection of the second part 16 with the internally threaded socket.

Referring to Figure 2, the connector 110 of the present invention is generally similar to that of the prior art, and the same numbers are used to indicate corresponding parts. However, the connector 110 of the present invention additionally comprises a wavy washer 80 which is placed over the proximal portion 54 of the first part fitting body 50 prior to assembly of the connector 1 10, and which therefore sits between the mid portion 56 of the first part fitting body 50 and the proximal portion 62 of the second part fitting body 60 upon assembly of the connector 1 10. The wavy washer 80 is compressed between the first part fitting body 50 and the second part fitting body 60, thereby ensuring that reliable electrical contact is made with both parts. In this way, electrical contact between the first part 12 and the second part 16 of the connector 1 10 is maintained at all times.

The connector 1 10 is particularly suited for use with electrically-conductive flexible conduit, such as that comprising a spiral-wound flexible metal tube within a plastic sheath. When this conduit is fitted over the distal end of the conduit insert 40, the spiral-wound flexible metal tube makes contact with the outer surface of the conduit insert, aided by the helical ridge 45. Electrical continuity is therefore provided between the metal tube, the first part 12 of the connector 1 10, and hence, via the wavy washer 80 and the second part 16 of the connector 110, to equipment connected to the second part 16 of the connector 110. The build up of a potential difference between different parts of the conduit system is therefore avoided, and it is possible to ground the system to earth via a single location.