GB2342461A - Submersible connector - Google Patents

Abstract

A submersible connector comprising a first connector part 2 for receiving a first optical member 14 and a second connector part 4 for receiving a second optical member 50, the first and second connector parts being connectable to allow optical coupling of the first and second optical members at an optical coupling region, the first connector part including liquid filter 24, and the first and second connector parts being constructed such that during their connection liquid filtered by the liquid filter is caused to flow from chamber 42 via channel 26 and apertures 28 through the optical coupling region so as to flush said region with filtered liquid. Chamber 42 is sealed by O-ring 48 on part 4.

Description

Connector This invention relates to a connector and more particularly to a submersible connector for connecting optical members, for example in deep water or at high pressure, for instance in wellhead applications.

Optical fibres are frequently used for communication purposes, and it is often necessary to form an optical connection between the ends of such fibres. This generally involves bringing together two connector components each supporting a respective fibre and making end-to-end contact between the fibres. In the case of underwater connectors, it is known to provide the connector components with end sealing arrangements so that the optical fibre ends are protected from the outside environment when the components are in a disconnected state, the end sealing arrangements opening up during connection to allow passage of one of the optical fibre ends therethrough in order to establish the optical connection.

It has been proposed for example in US-A-4 887 883 to provide the two connector components of an underwater optical fibre connector with end sealing arrangements each comprising a relatively thick (in the axial direction) seal member with an axial opening formed therethrough. The axial openings are kept closed by the resilience of the seal members when the components are disconnected, and during connection a wand structure supporting an optical fibre pushes its way through the mating seal members of the two components. However, with such an arrangement there is a risk of damage to the optical end face of the optical fibre caused by particles of sand, silt or the like which have lodged on the seal members, and there is a risk that the wand structure may be pushed out of line as it forces its way through the seal members. Moreover, if the connector is left in the connected state for a lengthy period of t ; le there is a potential danger that when it is disconnected the axial openings in the seal members will not reliably close up again, due to the phenomenon of"compression set"whereby there is a loss of elasticity in the material of the seal members. This can result in contamination of the regions where the optical fibre ends are supported.

Another arrangement using the idea of sealed chambers which open up during mating to enable an optical connection to be made is disclosed in WO-A-9 622 554. The arrangement is mechanically complicated and, as with other systems of this type, a relatively large number of moving parts are used.

An alternative form of submersible optical connector involves the use of gel or grease at the interface between two optical fibres. In one proposal, in the demated condition of two connector parts the respective optical fibre ends are covered by a volume of silicone grease. The outside surface of each grease volume is exposed to the external environment and there is no sealed enclosure and thus no seals which would have to open during mating. When the connector parts are mated, the grease is forced away from the optical fibre ends so that the fibre ends can make contact. Due to this mode of operation, a certain amount of grease in the female connector half is replaced by seawater each time the connector is demated. It is therefore recommended to replace the grease in the female connector half after 3-5 matings, with the inconvenience and difficulties such replacement entails.

According to the invention there is provided a submersible connector comprising a first connector part for receiving a first optical member and a second connector part for receiving a second optical member, the first and second connector parts being connectable to allow optical coupling of the first and second optical members at an optical coupling region, the first connector part including liquid filter means, and the first and second connector parts being constructed such that during their connection liquid filtered by the liquid filter means is caused to flow through the optical coupling region so as to flush said region with filtered liquid.

By flushing the optical coupling region with filtered liquid, e. g. filtered seawater, it is possible to flush away debris or other contaminants during connection. In general, it is possible to avoid the use of complicated mechanisms to open up sealed enclosures to allow optical coupling.

Advantageously, the connector parts are constructed such that relative axial movement of the connector parts during connection causes liquid flow. For example, one of the connector parts may comprise a receptacle and the other connector part may comprise a plug insertable into the receptacle during connection, wherein such insertion causes liquid to be forced through the liquid filter means. Thus a pumping action may be provided. Although the liquid filter means may be provided on the plug, it is preferably provided on the receptacle.

Preferably, the connector comprises a filter chamber from which, during connection of the first and second connector parts, liquid is expelled and forced through the liquid filter means. This liquid expulsion may be achieved by a piston, which may for example form one wall of the filter chamber.

During disconnection of the connector parts, liquid will normally be drawn back into the filter chamber, and in certain embodiments such reverse flowing liquid flows through the liquid filter means. In other embodiments, however, the connector has vent means for allowing liquid to flow into the filter chamber without passing through the liquid filter means during disconnection of the first and second connector parts. Such an arrangement advantageously avoids, during the disconnection process, drawing liquid from outside the connector which may contain sand or silt or other debris, into the region adjacent the filter means (i. e. the region which will be downstream of the filter means during the connection process). In cases where this region is of restricted size, e. g. a narrow passage or flow path, it may be particularly desirable to avoid a back flow into the region during disconnection.

The vent means is preferably a one-way valve, for example responsive to differential liquid pressures or to relative movement of the two connector parts, allowing flow into the filter chamber during disconnection but preventing flow out of the filter chamber during connection. The vent means can be located in or between any of the walls of the chamber.

In a preferred embodiment, the vent means comprises a sealing member axially moveable relative to a seat therefor, between a sealing position and a venting position. By arranging for the sealing member to be axially moveable, it can be automatically moved between the two positions in response to relative axial movement of the two connector parts, either to seal the filter chamber during connection or to vent the filter chamber during disconnection.

In one preferred form of the invention, in which the connector parts comprise a receptacle and plug, the plug is arranged to form a seal with the receptacle so as to define the filter chamber from which, during connection and entry of the plug into the receptacle, liquid is expelled and forced through the liquid filter means. The plug effectively forms a piston. In an alternative preferred form of the invention, in which again the connector parts comprise a receptacle and a plug, the receptacle comprises a piston engageable during connection by the plug. The piston then preferably seals with at least one wall of the receptacle to define, behind the piston, the filter chamber from which liquid is expelled during connection.

By providing the receptacle with such a piston, the liquid upstream of the liquid filter means during the connection process, contained in the chamber behind the piston, can be kept relatively clean.

Liquid is preferably caused during connection to flow forwardly along one of the connector parts to the optical coupling region. For example, if one of the connector parts comprises a receptacle, this may be provided with a forwardly projecting stem along which liquid may flow forwardly towards the optical coupling region. The liquid may be filtered before, during or after such forward liquid flow, depending on the position of the liquid filter means.

Preferably, a liquid flow path is defined in one of the connector parts such that during connection liquid flows from a radially outer portion of the liquid flow path to a radially inner portion of the liquid flow path. With such a flow path the liquid filter means can conveniently be arranged so that liquid flows radially through it. If the filter means extends circumferentially about the radially inner portion, being for example of conical or tubular form, it can present a relatively large area to the radial flow. In some embodiments, it may only be necessary for the filter means to extend about part of the radially inner portion. During connection, liquid preferably flows forwardly along the radially inner flow path portion towards the optical coupling region.

A channel for receiving one or more optical fibres is preferably provided radially inwardly of the radially inner flow path portion. A single such channel may be provided, for example on the central axis of the connector, or there may be a plurality of channels associated with a plurality of optical coupling regions.

In a preferred embodiment, there is provided a seal to seal the optical coupling region in the connected condition of the first and second connector parts. This can ensure isolation of the optical coupling region in the connected condition. Thus, in a preferred embodiment, the optical coupling region is flushed with filtered liquid and then sealed. Such a seal may be provided by a sealing member, for example an annular sealing member, on one connector part which presses axially against a seal abutment surface on the other connector part. Preferably, a transverse plane in which the seal is made is longitudinally offset in the upstream direction of liquid flow from the front faces of the optical members, so that the flow of filtered liquid during connection does not have to reverse in direction before passing over either front face.

Although it may be possible for the first and second optical members to make physical contact when connected, for example if each optical member is an optical fibre end supported in a ferrule, it may be better to arrange for the optical members to be spaced apart, e. g. axially, at the optical coupling region. A spacing will generally be more appropriate if expanded beam or collimated beam terminations are used, as are preferred.

In a preferred embodiment, in the connected condition of the first and second connector parts, the first and second optical members are spaced apart at the optical coupling region, which region contains filtered liquid. Where expanded beam or collimated beam terminations are used, their lenses will be chosen taking account of the refractive index of the fluid to be expected in the optical coupling region, normally filtered sea water or air, so that the beam of light will be parallel as it passes through the optical coupling region.

Preferably each of the first and second optical members is provided with a pressure resistant window at its front face. This can provide protection for optical components behind the window, such as optical fibres, against the environmental fluids and high pressures, e. g. up to 20,000 psi. An optical window may for example be supported in a metal surround by glass to metal sealing, which can achieve the desired hermetic seal.

A debris seal is preferably provided downstream of the optical coupling region. This will allow egress of liquid which has flowed through the optical region during connection of the connector parts, but will tend to prevent the entry of sand or silt or marine growth when the connector parts are first submersed or when they are mated or when they are demated.

Certain preferred embodiments of the invention will now be described, by way of example only, and with reference to the accompanying drawings, in which: Figure 1 is a longitudinal sectional view of a first embodiment of the connector; Figure 2a is a detail of parts of the first and second optical members just prior to connection; Figure 2b is an enlarged view of part of Figure 2a, showing further details; Figure 3 is a part-sectional view, on the lines III-III in Figure 1; Figure 4 is a longitudinal sectional view of a second embodiment of the connector; Figure 5 is a partial longitudinal sectional view of a third embodiment of the connector, shown during connection; and Figure 6 is a detail of parts shown in Figure 5, but shown during disconnection.

Referring to Figure 1, the first embodiment of the connector comprises a first connector part in the form of a receptacle 2 and a second connector part in the form of a plug 4. The front end of the receptacle opens out as a funnel 6 to assist initial insertion of the plug 4. A key-way slot 8 extends rearwardly from the receptacle front end, to ensure correct rotational alignment of the receptacle and plug during connection, by receiving a key 10 formed on the radially outer surface of the plug 4.

A tubular stem 12 extends forwardly from the rear of the receptacle 2 and supports at its front end a first optical member in the form of an expanded beam insert 14. On the radially outer surface of the insert a key 16 is provided to engage in a key-way slot 18 provided on the plug 4. The stem 12 has an inner tube 20 defining a channel along which optical fibres 22 are carried, the optical fibres being connected in known manner to the expanded beam insert 14. An annular sealing member 36 is provided around the front end of the expanded beam insert 14, the sealing member having a front surface 38 disposed slightly rearwardly of the front optical face 40 of the insert 14. The stem 12 has a filter tube 24, made of sintered ceramic or the like, disposed around the inner tube 20 to form a longitudinally extending annular flow passage 26 between the inner tube and the filter tube. At its front end the filter tube is formed with side vent openings 28, and just to the rear of these an annular bump seal 30 is provided around the outside of the filter tube. At its rear end the filter tube is formed with an annular flange 32, and to the rear of the flange 32 a rear cavity 34 is formed. Radially outwardly of the stem 12, an annular chamber 42 (or filter chamber) is defined.

The plug 4 of the second connector part has a forwardly extending tubular body 44 for engagement during connection in the annular chamber 42 of the receptacle 2. The tubular body 44 has a central passage 46 for receiving the stem 12 of the receptacle 2 during connection. An 0-ring seal 48 is provided around the front nose of the tubular body 44 to form a seal with the radially outer wall 47 of the annular chamber 42.

To the rear of the tubular body 44 a second optical member in the form of an expanded beam insert 50 is axially slidably supported in alignment with the central passage 46. The insert 50 is forwardly biased by a spring 52 and is prevented from rotation relative to the rest of the plug 4 by engagement of a key 54 in a keyway slot 56. The insert 50 is connected in known manner to optical fibres 58. An 0-ring seal 60 is provided around the outside of the insert 50 to prevent ambient liquid flowing rearwardly into the cavity housing the spring 52 and beyond.

As seen in Figure 2a, the insert 50 is provided with an annular seal surface 62 for engagement by the annular sealing member 36 of the receptacle 2. Slightly to the rear of the annular seal surface 62, there is provided an abutment surface 64 which, when the connector parts are fully mated, is engaged by the front face 40 of the insert 14. Thus, in the fully mated condition, a chamber 66 is defined between the front face 40 of the insert 14 and the front face 68 of the insert 50.

As seen in Figure 2b, the expanded beam insert 50 has at its front face 68 a glass window 61 sealed in a metal ring 63 which is welded at 65 into the main body of the insert 50. A lens 67 of the insert 50 is located behind the window 61 and is optically linked to the front end of an optical fibre 58. The lens 67 and the optical fibre 58 are thus protected against pressure and fluids. A similar sealing arrangement is provided for the expanded beam insert 14.

A radial passage 70 extends through the expanded beam insert 50 and through the wall of the tubular body 44. The radial passage 70 communicates with an annular recess 72 formed around the outside of the tubular body 44 and closed by an annular debris seal 74. The debris seal 74 is a two-way flap valve which stops larger items of debris entering the connector and also provides a barrier to marine growth inside the connector. The debris seal 72 acts when the connector parts are unmated as well as when they are mated. In addition, an annular lip seal 76 is disposed around the plug 4 to the rear of the debris seal 74 and is arranged to engage with the funnel 6 of the receptacle 2 when the connector parts are mated.

The operation of the submersible connector will now be described. The two connectors parts are submersed in water and their open front ends fill with water. When it is desired to mate the connector parts, the tubular body 44 of the plug 4 is inserted in the receptacle 2, with correct rotational alignment being achieved by engagement of key 10 in key-way slot 8.0-ring seal 48 at the front of the tubular body 44 engages with the radially outer wall of the annular chamber 42 in sealing manner. At about the same time the bump seal 30 formed around the outside of the stem 12 of the receptacle 2 engages the radially outer wall 45 of the central passage 46 of the tubular body 44. The ambient liquid, such as seawater, contained in annular chamber 42 is forced by the piston action of tubular member 44 entering the annular chamber 42 to pass through the filter tube 24, so as to enter rear cavity 34 and the annular flow passage 26 between the inner tube 20 and the filter tube 24. The liquid passes both through the elongate tubular wall of the filter tube 24 and through the rear annular flange 32, the combination providing a relatively large area of filter material through which liquid can flow. Any contaminants, such as sand or silt or the like, which have entered the annular chamber 42 are filtered by the filter tube 24, whereby downstream of the filter tube the liquid is filtered and effectively cleaned of contaminants.

A liquid flow path is thus defined in the receptacle such that during connection liquid flows from a radially outer portion of the liquid flow path, namely annular chamber 42, to a radially inner portion of the liquid flow path, namely annular flow passage 26. The liquid flow path then continues via the side vent openings 28 and into the tubular passage 46 defined in the tubular body 44 of plug 4. The filtered liquid thus flushes the central passage 46 and escapes via debris seal 74. Any contaminants in the plug 4 are expelled via debris seal 74 by the flushing action of the filtered liquid. This action continues as the connector parts are fully mated. During the connection process the axial spacing between the expanded beam inserts 14 and 50 decreases.

The connector is fully mated when the stroke distance 90 has been reduced to nothing. The final position of the expanded beam inserts 14 and 50 relative to each other is determined by the engagement of the front face 40 of the expanded beam insert 14 of the receptacle 2 with the abutment 64 of the expanded beam insert 50 of the plug 4. Positive abutting engagement is ensured by the forwardly spring biased mounting of insert 50, which is pushed rearwardly during the final connection procedure from its forward most position by the insert 14. It will be noted that during the mating procedure the flow of filtered liquid will be forwardly past the radially outer face of the sealing member 36.

Just before final sealing takes place the flow of liquid takes place laterally across the front face 40 of the insert 14 and the front face 68 of the insert 50, thereby tending to wash the front optical surfaces of the expanded beam terminations. At this stage, just prior to final mating, the flow of filtered liquid is constrained to follow a narrow flow path past the front faces of the inserts and there is therefore a relatively high speed of flow in this region, which assists the flushing effect.

Once the connector parts are fully mated, the chamber 66 then defines an axial spacing between the optical surfaces. The lenses of the inserts 14 and 50 are sealed behind the windows 61 which can withstand high pressure differentials. The lens are designed appropriately to allow for the refractive effect of the filtered liquid in the chamber 66. With certain designs of lens, the connector can operate in air as well as in submersed conditions. This is useful both to allow surface testing of the connector and to provide a dual use connector, i. e. one which can be used in or out of water.

During final engagement, a positive latching device will be utilised to secure the connector parts together.

This could be by a rotary or bayonet type latching mechanism. Alternatively a simple snap ring mechanism as described in European Patent No. 0566615 would be employed.

The embodiment shown in Figure 4 is generally similar to that of Figures 1-3, but is modified by the use of a conical filter 80 and the use of a piston 82 for engagement by the front nose of the plug 4. The piston 82 is forwardly resiliently biased by a spring 84 and is shown in its forward most position abutted against an annular shoulder 86 formed on the receptacle 2. The provision of the piston 82 provides improved control of the environment in the annular chamber 42, upstream of the filter 80 during the mating procedure.

Side vent holes 88 are formed in the wall of the receptacle 2, so that when the tubular body 44 of the plug 4 initially enters the receptacle 2 debris such as sand or silt can easily exit via the vent holes 88.

When the receptacle 2 is first immersed in water, the annular chamber 42 can fill with water which passes in via side vent openings 28, rearwardly along passage 26, into rear cavity 34 and through conical filter 80.

If any contaminants enter passage 26 and cavity 34 at this stage then they will be later expelled by the outward flow of filtered liquid during the mating procedure. In order to assist filling of the annular chamber 42 with water, and the removal of air, the connector may include some modified features. For example, the piston 82 may be formed with one or more openings communicating annular chamber 42 to the outside, such openings being arranged to be blocked by the front nose of the plug tubular body 44 during connection. Alternatively or additionally, a ceramic filter may be provided in the radially outside wall of the annular chamber 42, to permit entry of liquid during initial immersion. Such a filter will have a smaller cross-sectional area than that of the conical filter 80, so that during mating the major part of the liquid contained in annular chamber 42 is forced through the conical filter.

The mating procedure for the embodiment of Figure 4 is otherwise the same as that of the embodiment of Figures 1-3.

The embodiment shown in Figures 5 and 6 is generally similar to that of Figures 1-3, but has a modified sealing arrangement for the annular chamber 42.

The simple 0-ring seal 48 shown in Figure 1 is replaced by a shuttle seal 49 comprising a sealing ring 51 supported on a support ring 53 made of e. g. steel or plastic. The shuttle seal 49 is located in an annular groove 55 formed around the outside of the tubular body 44 of the plug 4. The width of the groove (in the longitudinal direction of the tubular body 44) is greater than the width of the shuttle seal 49, so as to allow the shuttle seal to move axially. The radially outer surface of the sealing ring 51 forms a seal with the radially outer wall 47 of the annular chamber 42 of the receptacle 2. A plurality of radial vent ports 57 communicate the annular groove 55 with annular chamber 42. The groove 55 is communicated with the outside via a plurality of longitudinal vent slots 59. In other respects, the embodiment shown in Figures 5 and 6 is generally similar to that of Figures 1-3.

The connection and disconnection in submersed conditions of the two connector parts of Figures 5 and 6 will now be described. During connection, the tubular body 44 moves relative to the receptacle 2 in the direction of arrow A. The shuttle seal 49 engages the wall 47 of the annular chamber 42 and is forced back to the rear of the groove 55 to form a seal against the rear groove face. Liquid contained in the annular chamber 42 is therefore unable to escape via vent ports 57 and is forced through the filter tube 24 into annular flow passage 26, as in the case of the operation of the embodiment of Figures 1-3.

When it is desired to disconnect the connector parts, tubular body 44 moves in the direction of arrow B shown in Figure 6 relative to the receptacle 2. The shuttle seal 49 is then forced to the front of the annular groove 55, allowing ambient liquid to enter annular chamber 42 via vent slots 59 and vent ports 57, as shown in Figure 6. As a result, as the volume of annular chamber 42 increases during the disconnection process, liquid is sucked in past the shuttle seal 49 and does not flow in reverse through the filter tube 24.

This prevents any contaminants which may have passed debris seal 72 from being drawn into the annular passage 26 inside the filter tube 24, which contaminants might otherwise affect the quality of the flushing liquid when the connector parts are next mated. Although a certain amount of contaminants may pass the debris seal 74 into the central passage 46 in the tubular body 44 of plug 4 during disconnection, once the connector parts are fully disconnected the passage 46 will be open to the outside environment and thus be unlikely to retain a significant amount of contaminants. Moreover, the maximum volume of the central passage 46, as seen in Figure 1 when the bump seal 30 first engages the radially outer wall 45 of the central passage 46 during the connection process, is smaller than the maximum volume of the annular chamber 42 which provides the source of liquid to be passed through the filter tube 24. Thus, in general, all the liquid contained in central passage 46 at the start of the connection procedure will be displaced by filtered liquid, thereby removing any remaining contaminants.

Each connector part may be provided with a protective cap to protect the optical surfaces of the inserts 14 and 50 when the connector parts are not mated. Such a cap may for example have a spring loaded cleaning device, such as a nylon brush or a soft sponge, arranged to move laterally across the optical surface, e. g. rotationally, when the cap is removed ready for the mating procedure.

The connector parts may include electrical contacts for making one or more electrical connections in addition to one or more optical connections, i. e. to form a hybrid connector. Contact pins and sockets as shown in GB 2192316 may be provided alongside the optical connection system.

Many modifications to the embodiments described above are possible within the scope of the invention.

For example, the liquid filter means is shown as provided on a receptacle connector part, but it could alternatively be provided on the plug connector part, e. g. being axially retractable during connection.

Claims (14)

1. Claims: 1. A submersible connector comprising a first connector part for receiving a first optical member and a second connector part for receiving a second optical member, the first and second connector parts being connectable to allow optical coupling of the first and second optical members at an optical coupling region, the first connector part including liquid filter means, and the first and second connector parts being constructed such that during their connection liquid filtered by the liquid filter means is caused to flow through the optical coupling region so as to flush said region with filtered liquid.
2. 2. A connector as claimed in claim 1, wherein one of the connector parts comprises a receptacle and the other connector part comprises a plug insertable into the receptacle during connection, and wherein such insertion causes liquid to be forced through the liquid filter means.
3. 3. A connector as claimed in claim 2, wherein the receptacle comprises a piston engageable during connection by the plug.
4. 4. A connector as claimed in claim 1,2 or 3, comprising a filter chamber from which, during connection of the first and second connector parts, liquid is expelled and forced through the liquid filter means.
5. 5. A connector as claimed in claim 4, comprising vent means for allowing liquid to flow into the filter chamber without passing through the liquid filter means during disconnection of the first and second connector parts.
6. 6. A connector as claimed in any preceding claim, wherein liquid is caused during connection to flow forwardly along one of the connector parts to the optical coupling region.
7. 7. A connector as claimed in any preceding claim, wherein a liquid flow path is defined in one of the connector parts such that during connection liquid flows from a radially outer portion of the liquid flow path to a radially inner portion of the liquid flow path.
8. 8. A connector as claimed in claim 7, wherein the filter means extends circumferentially about the radially inner portion.
9. 9. A connector as claimed in any preceding claim, comprising a seal to seal the optical coupling region in the connected condition of the first and second connector parts.
10. 10. A connector as claimed in any preceding claim, in combination with the said first and second optical members.
11. 11. A connector as claimed in claim 10, wherein, in the connected condition of the first and second connector parts, the first and second optical members are spaced apart at the optical coupling region, which region contains filtered liquid.
12. 12. A connector as claimed in claim 10 or 11, wherein each of the first and second optical members is provided with a pressure resistant window at its front face.
13. 13. A connector as claimed in any preceding claim, comprising a debris seal downstream of the optical coupling region.
14. 14. A submersible connector substantially as hereinbefore described with reference to Figures 1,2a, 2b and 3 or Figure 4 or Figures 5 and 6.