The present invention generally relates to an assembly for locking to the locking profiles of a tubular shaped member. More particularly the invention relates to such an assembly with easily replaceable locking members.
Particularly in the field of subsea wells, one can find a plurality of devices for coaxially joining large tubular members.
A well known solution is to arrange a split ring with radially arranged locking profiles and an inclined face. When forcing an activation sleeve against the inclined face, the split ring will move radially into a facing locking profile. In such a solution, the split ring will change its shape when being moved. Thus, some of the force from the activation sleeve will be used for this change of shape. Furthermore, the ring will be arranged with inherent tension when moved by the activation sleeve. In addition, a severe problem can arise if the split ring does not fully retract to its original shape during release. In such case, it may interfere with moving parts and prevent proper function.
Another solution is shown in patent publication U.S. Pat. No. 6,129,149, which describes a wellhead connector for connecting a wellhead Christmas tree assembly to a wellhead. This connector comprises a plurality of dogs adapted to be forced radially against facing locking profiles of the wellhead. Furthermore, the dogs can be forced in both radial directions by means of a first and a second drive means. The solution described in U.S. Pat. No. 6,129,149 occupies much radial space and seems to be suited only for locking to the outwardly facing profiles of a tubular member, unless the inner diameter of the tubular member is particularly large.
An object of the present invention is to provide a connector assembly which can be used to connect to inner profiles of a tubular member, and which does not need to alter the shape of any components during connection or disconnection. As will appear from the following disclosure, this is achieved with the connector assembly according to the invention, along with other advantageous features. As will appear from the following descriptions, the connector assembly is, however, not restricted to being connected to inner profiles, as it indeed can be designed for connection to outer profiles of a tubular member.
According to the invention, there is provided a connector assembly for connection to a tubular element, the assembly comprising a plurality of locking elements which are movable in a locking and an opposite unlocking direction, the locking elements comprising locking profiles adapted for locking engagement with facing locking profiles of said tubular member. The invention is characterized in that said plurality of locking elements are adapted to be moved in a locking direction as a result of movement of an activation sleeve in a first direction, wherein the movement in the locking direction is obtained as a result of a part of the locking element or the activation sleeve sliding against an inclined locking surface of the other. Furthermore, said plurality of locking elements or said activation sleeve comprise guiding elements which are adapted to slide against inclined unlocking guiding surfaces of the activation sleeve or the locking elements, respectively, wherein a movement of the activation sleeve in a second direction results in a movement of the locking element in an unlocking direction, as the inclined unlocking guiding surfaces exhibit an inclination to said first and second directions, as well as to said locking and unlocking directions. The activation sleeve comprises axially extending activation sleeve protrusions which have spaces between them. In addition,
Preferably, the locking and unlocking directions are parallel and crosswise to said first and second directions, which are also parallel. The term crosswise shall be conceived as non-parallel, and is not restricted to the meaning of the term perpendicular. In a preferred embodiment however, the locking and unlocking directions are perpendicular with respect to the first and second directions.
In an embodiment of the invention, the locking elements comprise side walls which define a void or space between them. In this embodiment, the activation sleeve comprises axially extending activation sleeve protrusions having spaces between them, wherein the activation sleeve protrusions extend into said voids of the locking elements. Preferably, side flanges of the locking elements can then be arranged in the spaces between the activation sleeve protrusions.
The inclined unlocking guiding surfaces or an extension of these are preferably interrupted by an absence of surface, so that the locking element can be pulled past the guiding element and out of engagement with the connector assembly, when the guiding element faces this absence of surface. In this way, the locking elements can be removed easily from the connector assembly without cumbersome dismantling. As will become apparent from a more detailed description with reference to the appending drawings, the locking elements can be pulled right out of the assembly when the activation sleeve is in the proper position, even without any tools or equipment.
Preferably, the activation sleeve has inclined locking surfaces with an inclination to said first direction and said locking direction, wherein said inclined locking surfaces are adapted to slide against facing inclined locking surfaces of the locking elements when the activation sleeve is moved in the first direction. Thereby a movement of the locking element in the locking direction is provided when the activation sleeve is moved in the first direction. The inclined locking surfaces of the locking elements extend preferably across a substantial part of the locking element, across the locking direction. Also preferably, the surfaces extend across a centre part of the locking element. However, each locking element can also comprise a plurality of inclined locking surfaces, arranged with a distance to each other. As will be appreciated by a person skilled in the art, however, a large surface will facilitate a large force on the locking element in the locking direction.
The inclined locking surfaces of the locking elements can be continued and deflected to second holding surfaces which are substantially perpendicular to the locking and unlocking directions. The activation sleeves can exhibit first holding surfaces adapted to abut against said second holding surfaces when the locking elements are in a locked position. Such abutting holding surfaces are preferably large and will preferably not transfer forces in the first or second direction between the locking elements and the activation sleeve, once properly arranged in the locked position. This is due to their extension being perpendicular to the locking and unlocking directions.
Furthermore, the first holding surface and second holding surface can be arranged to maintain a pre-tension of the locking element towards the locking direction when in the locked position. Also, at least one pre-tension transition surface can advantageously be arranged as a transition surface between said inclined locking surfaces and said second or first holding surface, respectively. The pre-tension transition surface is preferably arranged such that pre-tension is at least partially released before the guiding elements enter into engagement with the unlocking guiding surfaces, when the activation sleeve is moved in the second direction in order to unlock the locking elements.
It should be noted that said surfaces are not necessarily strictly plane surfaces. For instance, the pre-tension transition surfaces may be curved. Also, instead of an edge defining the transition between various surfaces, there may be arranged rounded surfaces in order to provide less wearing of the abutting parts.
The activation sleeve can comprise a plurality of pre-tension surfaces or pre-tension transition surfaces adapted to enter into sliding contact with facing pre-tension transition surfaces of the locking elements as the activation sleeve is moved further in the first direction after having moved said locking elements into a position where their locking profiles are in engagement with facing locking profiles of the tubular element. This further movement in the first direction results in that said pre-tension transition surfaces of the activation sleeve slide against said pre-tension transition surfaces of the locking members. This will further result in a pre-tension compression force between said activation sleeve and said locking elements, as the locking elements will be clamped between the activation sleeve and the tubular element.
In a further embodiment of the connector assembly according to the present invention, it preferably comprises pre-tension transition surfaces on the activation sleeve and the locking elements, which are adapted to provide pre-tension of the locking elements in the locking direction as said pre-tension transition surfaces slide against each other when the locking sleeve is moved in the first direction. In this embodiment, the pre-tension transition surfaces exhibit an angle of inclination which is between and different from the corresponding angles of said inclined locking surfaces and said first direction. Due to this, one can obtain a large pre-tensioning force in the locking direction. This will become more apparent through the more detailed description of an example embodiment further below.
The term tubular, as used above, shall not be confined to mean concentric circular shapes. Instead, tubular includes various circular shapes, such as an elliptical shape, as well as polygonal shapes, such as a square or rectangular shape. That is, the connector assembly according to the present invention is suited for connection to pipe elements having for instance a rectangular or elliptical cross section.
The locking profiles on the locking elements can be any kind of shape or form adapted to engage with a facing shape or form in order to create a locking effect against mutual movement between the two shapes or forms, as will be appreciated by a person skilled in the art.
All of the guiding elements can preferably be attached to a common actuation sleeve. Thus, by moving one actuation sleeve, all the locking elements can be actuated simultaneously.
A preferred application of the wellhead connector assembly according to the invention is as a locking assembly of an internal tree cap, arranged for being releasably connected to an inner locking profile of a Xmas tree spool.
Another preferred application is the use of the connector assembly according to the invention with a ultra high pressure tubing hanger.
The connector assembly is particularly useful for applications in connection with deepwater subsea wells. Due to its structure, particularly solid locking elements can be used, a feature which make the connector assembly applicable for high pressure applications in deep waters, for instance for pressures of 15-20 000 psi. Depending on the dimensioning of the assembly, it can also be used at even higher pressures.
In order to illustrate the various features of the present invention more thoroughly, an example of embodiment will be given in the following with reference to the drawings, in which
The activation sleeve 101 is fastened to the ITC 103 main body with a first set of bolts 108 in such a way that it can move reciprocally in a certain distance in the axial direction.
By connecting a tool (not shown) to the upper end of the assembly shown in
The locking dogs 105 has outwardly facing locking profiles 107, adapted to engage with internally facing locking profiles inside the bore of a tree spool (not shown).
In
For the sake of clarity, a first and second direction D1, D2 are illustrated in
In
Referring now to
When this movement takes place, the guiding elements 109 (
In an alternative embodiment, the inclined locking surface 113 could be omitted, using the guiding elements 109 to move the locking dogs 105 in the locking direction DL by sliding on the narrower inclined locking surface 113b. However, one would then not be able to achieve the same amount of force on the locking dogs 105 in the locking direction DL.
Referring to
When the activation sleeve 101 has moved down into its lower position, in the first direction D1, its plurality of first holding surfaces 122 (
When moving the activation sleeve 101 axially upward, i.e. in the second direction D2, the guiding elements 109 will slide against the inclined unlocking guiding surface 111. This will pull the locking dog 105 radially inward, in the unlocking direction DU. As the force needed to pull the locking dogs 105 in the unlocking direction DU is small, when compared to the possible forces in the locking direction, the relatively narrow surfaces of the inclined unlocking surfaces 113 will be sufficient.
The function of moving the locking dogs 105 in the locking direction DL and the unlocking direction DU is shown more clearly in
As mentioned, in
In
From the situation shown in
As can be appreciated from
Furthermore, as appreciated by a person skilled in the art, one could also adjust the connector assembly 100 in such way that an upward movement of the activation sleeve would force locking dogs into locking engagement, instead of a downwardly directed movement.
The pre-tension transition surfaces 124, 126 also have advantage when moving the locking dog 105 in the locking direction DL. In this case, the inclined locking surface 113 may function as a sliding surface for moving the locking dog 105 into the locking position, whereas the pre-tension transition surfaces 124, 126 can function as pre-tensioning surfaces. That is, when the locking dog 105 has moved into the locked position by sliding against inclined locking surface 104 on the activation sleeve 101, the sliding of the pre-tension transition surface 124 of the activation sleeve 101 against the pre-tension transition surface 126 of the locking dog 105 will provide for pre-tensioning of the locking dog 105. As will be appreciated by the person skilled in the art, the lower degree of inclination of the pre-tension transition surfaces 124, 126 is advantageous in order to achieve high forces in the locking direction DL.
An especially advantageous feature of the connector assembly according to the embodiment illustrated in the drawings, is that by moving the guiding elements 109 upwards and out of or past the space between the retaining faces 125a, 125b (referring to the embodiment according to
In order to keep the dogs 105 in place when the connector assembly 100 is not in use, the guiding elements 109 should be arranged as shown in
Thus, the dogs 105, being parts which may be exposed to large forces and thereby may suffer wearing, can be easily replaced. One could also imagine such replacement being necessary in order to arrange dogs with locking profiles 107 of a different design or material. Also, one may want to replace the dogs in order to change them into dogs with another inclination of the unlocking and/or locking guiding surface 111, 113.
The number of locking elements or dogs 105 arranged peripherally about the connector assembly should preferably be two or more, for instance four, six, or eight. This number and the particular design of the locking elements should be chosen by the skilled person according to use and requirements.
Moreover, in the embodiments described with reference to the drawings, the activation sleeve 101 moves in a direction perpendicular to the movement of the dogs 105. However, as will be appreciated by a person skilled in the art, the direction of the dogs 105 can indeed be non-perpendicular in relation to the moving direction of the sleeve.
In a further variation of the embodiment described above, the activation sleeve 101 can be replaced by separate activation means. For instance, each dog 105 can be connected to a separate activation means, or a plurality, but not all dogs, can be connected to a common activation means.
It should also be noted that the connector assembly according to the invention is not restricted to subsea well elements, such as the tree spool in the above embodiments. On the contrary, it is applicable in a wide range of technical areas, onshore and offshore.
Number | Date | Country | Kind |
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20090253 | Jan 2009 | NO | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2009/067877 | 12/23/2009 | WO | 00 | 6/10/2011 |
Publishing Document | Publishing Date | Country | Kind |
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WO2010/081621 | 7/22/2010 | WO | A |
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Number | Date | Country | |
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20110241335 A1 | Oct 2011 | US |