GB2197407A - Connector - Google Patents

Abstract

A connector for the coupling of two elements 1,2 on which coupling flanges 3,4 have been provided on the connection ends facing one another, comprises clamps 37 for gripping around the two coupling flanges and pressing them against one another, and a slidable coupling sleeve 12 designed to cause the clamps to engage with and press the coupling flanges against one another. The clamps 37 are mounted by means of links 38 inside a holding ring 31 which is mounted so as to have limited axial movement within the coupling sleeve 12, said coupling sleeve having impact parts 14,32 for striking interaction with the holding ring in both axial directions. <IMAGE>

Description

SPECIFICATION Connector The invention relates to a coupling device (connector) for coupling of two elements on which coupling flanges have been provided on the connection ends facing one another, com- prising clamps for gripping around the two coupling flanges and pressing them against one another, and a slidable coupling sleeve designed to cause the clamps to engage with and press the coupling flanges against one another.

The invention has been developed in connection with the need to be able to connect two elements provided with coupling flanges in a manner which is operationally safe and can be directed by remote control, and in particular the invention is intended for utilization under water in the coupling of elements-for example two pipelines -- in connection with the extraction of oil and gas.

An especially important area of application is that of subsea stations at a depth that is so great that the use of divers either is prohibited or is not recommended, so that one must rely on remote control or on the use of mini-submarines. in both, cases, strict requirements must be set for the coupling devices that are to be utilized. Thus, it must be possible to close and open all the connectors in a subsea station or module by means of hydraulic systems, and one must be able to detect whether each respective connector is fully closed or fully open, at the same time as it must be possible to test the tightness of the closed connection.

A further requirement is that such connectors must open with great certainty after having been closed and inactive for long periods of time. It must also be possible to carry out continuous monitoring of the connectors in order to detect possible leakage. The connector must also be protected against sea water and impurities.

The invention is based on a known and accepted coupling device wherein the connection of two elements is accomplished by means of clamps which are forced radially inwards, gripping around two coupling flanges that are placed opposite each another. The flanges are pressed inwards by means of a coupling sleeve which is moved in such a way that it forces the clamps inwards into an encircling clamping engagement with the two coupling flanges. Such a connection is strong and secure.

The coupling sleeve can advantageously be designed to have an internal angle of taper such that through axial displacement of the coupling sleeve it will interact with the clamps and push these radially inwards. If the angle of taper is not too great, the friction will prevent the sleeve from sliding back again. However, the friction coefficient may increase as time passes, especially in a corrosive environment. In such cases, they may arise difficulties when one wishes to force the sleeve back and to open the connection. There is also a possibility that the connector will "seize" totally so that it cannot be opened.

Taking this problem situation as a point of departure, the invention is aimed particularly at providing a connector of the type described in the introduction, a connector whose locked or closed position is based on geometric factors and not on the forces of friction.

Therefore, according to the invention there is proposed a connector for coupling of two elements on which coupling flanges have been provided on the connection ends facing one another, comprising clamps for gripping around the two coupling flanges and pressing them against one another, and a slidable coupling sleeve designed to cause the clamps to engage with and press the coupling flanges against one another, the connector according to the invention being characterized by the feature that the clamps are mounted by means of links inside a holding ring mounted so as to have limited axial movement within the coupling sleeve, said coupling sleeve having impact parts for striking interaction with the holding ring in both axial directions.The holding ring advantageously is designed such that it functions as an annular torsional spring which makes possible an over-centering movement of the links.

To make the connection, the two elements are brought into reciprocal position with their coupling flanges opposite each other, and by means of the coupling sleeve the clamps are then forced radially inward, each of them gripping around the two coupling flanges and pressing them together. The coupling sleeve pushes the holding ring and the links axially over the clamps suspended therein. The clamps will engage with one of the coupling flanges and gradually be pressed inwards and grip both coupling flanges, and press them together. The inward radial movements of the clamps is brought about by the fact that the links gradually take on a more radial orientation. After the links have reached the radial position, the holding ring is pushed a slight distance further, so as to achieve an overcentered locking effect of the links.This provides a mechanical locking which is based on the geometry of the system and not on friction. Such mechanical locking also means that vibrations will not be able to cause an unwanted unlocking/opening.

When the links are pushed past the radial position mentioned, some of the radial prestress will be released. To keep this relaxation within acceptable limits, the whole mechanism must have sufficient elasticity. This is achieved by virtue of the holding ring's being designed to function as an annular torsional spring. When the connection is to be opened, only a relatively small force is required to move the links back again past the radial position. The almost radial links yield an amplification of power such that even a small motive force will be sufficient to provide a strong outwardly directed driving force on the clamps. Between the clamps and the coupling flanges a relatively large compression angle is used, which provides further assurance that the clamps will loosen from the flanges.

In an advantageous embodiment of the connector according to the invention, the holding ring consists of two annular bodies which are fastened together, the annular bodies bearing against one another with their respective annular end surfaces, with possibility for limited reciprocal rotational movement in an axial section, at the same time as each clamp is suspended in a parallel link mechanism and that each of the two parallel links is mounted in its own annular body. The two annular bodies can then rotate in relation to one another, seen in axial section through the holding ring, so that the desired elasticity is achieved.

In a practical embodiment, said annular end surfaces may have interacting ridge and hollow (depression) elements which provide for the desired limited reciprocal rotational movement.

In order to absorb possible misalignments between the individual components, it may be advantageous to position elastically resilient elements between the holding ring and the coupling sleeve, preferably in the form of sliding pads inserted in the inner wall of the coupling sleeve. These elastically resilient elements would be able to absorb any misalignments and would also contribute toward taking up slack in connection with the over-centering movement.

A particularly advantageous embodiment is one in which the coupling sleeve functions as a part of an annular piston in a hydraulic cylinder/piston device. The annular piston is slidably received in a cylinder housing which is attached to one of the elements to be connected. Over part of its cylindrical inner wall the cylinder housing has a collar which has sealed-off sliding engagement with a constricted cylindrical section of the annular piston, whilst the annular piston on both sides of this constricted cylindrical section has sealedoff sliding engagement with the cylindrical inner wall of the cylinder housing whereby a working chamber is formed on both sides of the collar, into each of which working chambers there opens a respective tube for a working medium.By pressurization of one or the other of the working chambers, the annular piston could be pushed in one direction or the other, and thereby interact with the holding ring and the clamps and bring about the opening or closing of the connection.

An important measure for reducing the danger of defect or malfunction during the opening of the connection is the protecting of the connection parts against corrosion. In this connection, especially, it is important to be able to protect all sliding surfaces and vital parts against the effects of the sea water.

This is achieved according to the invention by the provision of a closed chamber within the closed connection, which can be flushed out for removal of the sea water and of possible impurities.

In the connector described above, having an annular piston and cylinder housing, it is according to the invention therefore proposed that at least one of said elements to be connected should be provided with a flange within its coupling flange; and that one of the elements should form a bottom of the cylinder housing, optionally having a flange as mentioned; that the flange on the other element should be positioned and designed such that the annular piston's opposing end surfaces will achieve sealing engagement with this flange in its one end position, in which end position the connection is locked; and that there should be two connecting passages for attaching the respective flushing tubes, opening into the chamber between the annular piston and the cylinder housing's bottom, one of the passages freely opening at all times into the chamber whilst the other passage is closed off by the annular piston when this is in its second end position, in which second end position the connection is open.

In the closed or locked connector position, it would be possible by means of a flushing medium to flush out the outwardly closed-off chamber between the cylinder housing's bottom and the flange on the second element.

It is also possible to carry out a status test and a tightness test of the connector, since one can pressurize the interior of the cylinder housing by means of said flushing tubes.

When the connection is open, one of the passages will be closed. The other passage is open. If one closes the tube from the latter open passage and pressurizes the other tube, then if such pressurization does not give a positive result, one could ascertain that the connector is in an intermediate position. If a pressure rise can be detected, then two options remain, and these can be distinguished by opening the tube which to begin with was closed. If one can still detect that pressurization has taken place, this means that the connectionis fully open. If pressurization cannot be confirmed, the connection would be fully closed.

By keeping both of the flushing tubes open, one may carry out the flushing operation and the flushing medium can be returned to the surface for possible detection of leakage.

Moreover, such a flushing medium would also exert a closing force on the annular piston and keep this in closed position.

The invention will be described in more detail with reference to the drawings, where: Figure 1 shows a section through the connector according to the invention, the upper part of the section showing the connector in closed position, while the lower part shows the connector in open position, and Figure 2 shows a combined section and end view of the holding ring and appurtenant components.

The embodiment example is related to a connector for coupling of two pipelines 1 and 2. Pipeline 1 at its end is formed with a coupling flange 3; pipeline 2 is designed with a coupling flange 4 at its connecting end. A short distance inside the coupling flange 3, the pipeline 1 is provided with one more flange 5, and similarly pipeline 2 is provided with a flange 6 inside its coupling flange 4.

A cylinder 7 is placed with one of its end surfaces on the flange 6 and securely fastened thereto by means of several screws 8. Between the cylinder's end surface and the flange there are inserted suitable seals, for example, O-rings 9. The cylinder 7 internally has a collar 10 in which there are inserted two encircling sealing rings 11 which provide a sliding seal against an annular piston 12 disposed in the cylinder.

This annular piston 12 is constructed of several parts, namely a first annular piston crown 13, a second piston crown 14, and an intermediate piston skirt 15. The piston crowns and the piston skirt are held together by means of screw bolts 16, 17. At each end the piston skirt 15 is recessed, and in these two recesses are inserted respective sealing means 18 and 19. These sealing means provide a sliding seal against the cylinder's inner wall on each side of the collar 10. On each piston crown there is in addition provided a lip seal, 20 and 21, respectively.

In this manner, on each side of the collar 10 there is formed a working chamber, 22 and 23, respectively. These working chambers are connected to their respective tubes 24, 25 for the working medium,so that the chamber's volume may be pressurized or depressurized as needed.

The piston crown 14 on its end side facing toward the flange 5 is provided with an annular seal 26 which forms a tight seal against the flange 5 in the connector's closed position (the upper half of the sectional drawing in fig.

1). Thus, in the connector's closed position, there will be a closed chamber 27 inside the cylinder housing formed by the cylinder 7 and the flange 6.

A through-going bore 28 has been made in flange 6 for connection to a flushing tube, not shown. Further, there has been made in flange 6 a through-going bore 29, also for connection to a flushing tube not shown in the figure. While the bore 28 is placed in such a manner that it will at all times be free and thus open toward the chamber 27, the bore 29 is placed such that it will be closed by the piston crown 13 when the connector is in its open position (the lower half of fig. 1).

The piston skirt 15 is cup-shaped, as shown, with a central opening 30 in the bottom of the cup. Inside piston 12 there is provided a holding ring 31 which has limited axial movement in the piston, between the piston crown 14 and the bottom part 32 of the cupshaped piston skirt 15.

The holding ring is constructed of two annular bodies 33, 34, which bear against one another as shown, the annular body 33 having an encircling groove 35 which engages with an encircling ridge 36 on the annular body 34.

Thus there is made possible a reciprocal twisting of the two annular bodies in the axial section.

In the holding ring's 31 opening there are provided a plurality of clamps 37. Each of these is suspended in the holding ring by means of links 38. In the embodiment example, each clamp 37 is suspended by means of four links 38, with the clamp hanging by two links in the annular body 33 and by the two other links in the annular body 34.

Thus, each clamp is mounted in the holding ring by means of a parallel link mechanism which comprises four links 38, articulately mounted in the holding ring and the clamp, respectively, by means of respective pins 39, 40 (fig. 2).

The two annular bodies 33, 34 are held together by means of a number of bolts 41.

In the embodiment example, between the inner wall of the piston skirt 15 and the holding ring 31 there are provided elastically resilient sliding pads 42, 43 which have been inserted in the annular piston.

The connector functions in the following manner: From the starting position shown in the lower half of fig. 1, the two elements to be coupled, 1 and 2, are brought together to the position shown in the upper half of fig. 1.

That is to say, the flanges 3 and 4 bear against one another. Between the coupling flanges there lies a metal seal 44. The piston 12 is in the end position shown in the lower half of fig. 1. A working medium is supplied to the working chamber 22 through the inlet 24, whereby the annular piston 12 together with its appurtenant components is moved toward the left in fig. 1. The bottom section 32 of the annular piston will strike against the opposing end surface of the holding ring 31 -which is to say, on the annular body 34 --and will carry this along with it in its movement toward the left. The clamps 37 will impact against the conical back side 45 of the coupling flange 4 and will be pressed inwards and grip around both coupling flanges 3 and 4, as shown in the upper half of fig. 1.The links 38 will reach a radial position and, in such position, will press the clamps radially inwards so that these, for their part, will clamp the coupling flanges 3 and 4 against one another as a consequence of the clamps' engagement with the back sides 45 and 46 of the respective coupling flanges 4 and 3.

When the links 38 have reached the radial position, the movement of the annular piston 12 continues slightly, so that an over-centering of the links is achieved. This last overcentering movement is limited by the engaging impact between the end surfaces 47 of the clamps and the surfaces 48 on the holding ring 31 lying above these.

One now has the connection condition as shown in the upper half of fig. 1. With a concluding movement of the annular piston, its piston crown 14 will have come into contact with the flange 5 on the pipeline 1, so as to achieve a sealed-off condition with the help of the seal 26.

In the condition shown in the upper half of fig. 1, a mechanical locking is achieved which is based on geometry and not on friction.

When the links are pushed past the radial position, some of the radial prestress will be released. In order for this relaxation to be kept within acceptable limits, the mechanism must have a certain elasticity. This is achieved in embodiment example 1 by the feature that the annular bodies 33, 34 may be twisted slightly relative to one another in the axial cross-section, so that the annular bodies function as annular torsional springs. Any radial movement of ring 31 will be absorbed by the elastically resilient pads 42, 43. Such radial movement will occur if the flanges 3 and 4 are not completely parallel (are not in contact around the entire circumference) when the locking is introduced.

After completed coupling, the chamber 27 will be sealed off from its surroundings. Sea water found in the chamber 27 can be flushed out by sending a flushing medium in through the bore 29 and out through the bore 28. If desired, one can execute a continuous flushing, with the flushing medium going up to the surface or to a suitable observation place, where any possible leakages can be observed.

The pressure of the flushing medium in the chamber 27 will maintain a closing force on the locking mechanism. If the pressure in the chamber 27 should drop to under the static outside pressure, the connector will begin to open, but the seal 29 then will immediately loose its effect and an equalization of pressure will occur before the holding ring 31 is affected and allows the connection to open.

To test the connector, the chamber 27 may be pressurized in order to detect whether the connection is closed and tight. For such pressurization, the bores 28 and 29 are used. In order to investigate the condition of the connection, the tube connected to the bore 28 is closed. If one is now unable to pressurize the tube connected to the bore 29, this means that the connector is in an intermediate position. If one can pressurize the tube which is connected to the bore 29, then there are two options, and these can be distinguished by opening the tube which is connected to bore 28. If the tube connected to the bore 29 still can be pressurized, this means that the connector is fully open. If the tube cannot be pressurized, then this means that the connector is fully closed.

A rupture in one or both of the two tubes (not shown) that are connected to the bores 28 and 29, respectively, will always give an intermediate position" as the test result, and this in all cases will mean that one is confronting an error situation which must be corrected.

The connector naturally can be modified in various ways. In this regard, the flanges 5 and 6 do not necessarily have to be actual flanges. Here, one could well be dealing with wall surfaces or the like, which are used for the same purpose as the flanges. The elastically resilient rings 42 and 43 are not absolutely necessary, and the holding ring can also be designed in ways other than those shown to achieve the torsional spring effect mentioned.

When the connector is to be opened, the working chamber 23 is pressurized, while the working chamber 22 is depressurized. The annular piston 12 will then move toward the right in fig. 1 and take with it the holding ring 31, whilst the annular piston crown 14 will make contact with the holding ring after a brief movement. The seal 26 will loose its sealing effect against the flange 5, and pressure is released in chamber 27. The links 38 will go past the radial position and pull the clamps 37 radially outwards. The annular piston 12 goes all the way to the bottom of the cylinder chamber 27 and closes off the bore 29. The pipeline 1 now can be withdrawn.

The taper angle for the surfaces 45 and 46 can be selected such that the clamps may be readily released and will not be stuck as a result of friction. A preferred taper angle for the surfaces 45 and 46 is 1400 -that is to say, the angle between the two conical surfaces in the axial section would be 40#.

Claims (8)

1. A connector for coupling of two elements on which coupling flanges have been provided on the connection ends facing one another, comprising clamps for gripping around the two coupling flanges and pressing them against one another, and a slidable coupling sleeve designed to cause the clamps to engage with and press the coupling flanges against one another, characterised in that the clamps are mounted by means of links inside a holding ring which is mounted so as to have limited axial movement within the coupling sleeve, said coupling sleeve having impact parts for striking interaction with the holding ring in both axial directions.

2. A connector in accordance with claim 1, characterised in that the holding ring is designed such that it functions as an annular torsional spring which makes possible an over-centering movement of the links.

3. A connector in accordance with claim 1 or 2, characterised in that the holding ring consists of two annular bodies which are fastened together, said annular bodies bearing against one another with their respective annular end surfaces, with possibility for limited reciprocal rotational movement in an axial section, that each clamp is suspended in a parallel link mechanism and that each of the two parallel links is mounted in its own annular body.

4. A connector in accordance with claim 3, characterised in that said annular end surfaces have interacting ridge and hollow elements.

5. A connector in accordance with any one of the preceding claims, characterised in that the holding ring is slidably mounted in the coupling sleeve with intermediate elastically resilient elements, preferably in the form of rings inserted in the inner wall of the coupling sleeve.

6. A connector in accordance with any one of the preceding claims, characterised in that the coupling sleeve forms a part of an annular piston which is slidably received in a cylinder housing, which cylinder housing is attached to one of said elements to be connected, and which over part of its cylindrical inner wall has a collar which has sealed-off sliding engagement with a constricted cylindrical section of the annular piston, said annular piston having on both sides of this constricted cylindrical section sealed-off sliding engagement with the cylindrical inner wall of the cylinder housing, whereby a working chamber is formed on both sides of the collar, into each of which working chambers there opens a respective tube for a working medium.

7. A connector in accordance with claim 6, characterised in that one element of the said elements which are to be connected forms a bottom in the cylinder housing, and that the other element has an ambient surface which is placed and designed such that the opposing end surface of the annular piston will achieve sealing engagement with the surface in its end position, in which end position the connection is locked, and in that two connecting passages for attaching the respective flushing tubes, open into the chamber between the annular piston and the bottom of the cylinder housing, one of the passages freely opening at all times into the chamber, whilst the other is closed off by the annular piston when this is in its second end position, in which second end position the connection is open.

8. A connector for coupling of two elements substantially as hereinbefore described with reference to the accompanying drawings.