Patent Application
20120325335
The present invention relates to a coupling for the releasable coupling of pipes or parts thereof.
When material such as silt, sand, stones, blocks and the like is planted on a water bottom and/or when bed material is removed from a water bottom, e.g. in the dredging thereof, an assembly of pipes placed one behind the other, via which the material can be transported from or to the bottom, is attached to a vessel, for example a dredging ship. To this end, the vessel is navigated to above the location at which the material must be planted or from which the material must be removed. After this, the pipes are placed one at a time one behind the other and coupled together. The material transport between the water bottom and the water surface can then be regulated via the pipe assembly. A known solution comprises the stacking of pipelines which are held together with a steel cable. A drawback of the known pipe assemblies is that the maximal combined length of the pipes is limited. In practice, lengths up to a maximum of about 500 metres are feasible. The assembly must be resistant to high loads formed principally by a combination of traction and bending moment. In place of the stacking of pipes, a coupling has been devised which makes it possible to couple the pipes in a quick and/or automatic manner.
The pipe parts can be slid one into the other, the lugs of one pipe part being able to be rotated behind the lugs of the other pipe part. Such a bayonet coupling is relatively weak, however. As the axial forces upon the pipe parts increase, the lugs of the coupling will need to be made heavier. The result of this is that the coupling becomes heavy and bulky.
The object of the present invention is to provide an improved coupling in which at least one of the said drawbacks has been overcome or, at least, lessened.
A further object of the invention is to provide a light, slender coupling which can nevertheless absorb a relatively large axial force.
It is also an object of the invention to provide a coupling with which pipes can be coupled to one another or uncoupled from one another in a relatively quick and/or simple manner.
According to a first aspect of the present invention, at least one of the objects or other objects deriving from the following description is achieved in a coupling for the releasable coupling of pipe parts, the coupling comprising:
By virtue of a suitable size and placement of the lugs (herein also referred to as teeth or projections), space can be present between the lugs of one pipe part (for example an inner socket) in order to allow the lugs of the other pipe part (for example an outer socket) to pass. By then twisting one pipe part over a certain length (for example one lug length) to the right or left and axially displacing it, it is possible to bring the second row (and possibly more rows) into engagement.
In this state, in which the lugs of the first pipe part engage on the lugs of the second pipe part, the lugs of one pipe part are preferably all (or, at least, a large part of them) located opposite the lugs of the other. In the case of two rows of lugs, the full circumferences of the pipe parts, or a large portion thereof, are then eventually in mutual engagement via the lugs provided thereon. This makes the coupling in the axial direction very strong, without the need to make the coupling extra heavy. In this way, a light and slender coupling is able to be obtained. If more than two rows are used, the pipe parts can be coupled to one another over more than the full circumference, which can make the structure yet more resistant to axial forces.
In one embodiment of the invention, the lugs of successive rows are arranged in the axial direction substantially in the line with one another. That is to say that the lugs of all successive lugs (or, at least, a number thereof) are not offset. If the lug teeth are not offset, merely an axial movement is sufficient to bring the two or more lug rows into position, whereafter a short twist to the left or right can fix the pipe parts in the axial direction and the coupling is realized. In a further embodiment, the pipe parts are consequently arranged such that, essentially with just an axial mutual displacement of the pipe parts, the pipe parts can be slid wholly in and out of one another, and/or, essentially with just a simple mutual twisting of the pipe parts over substantially one lug length, the lugs of the different rows can be made to engage on one another for coupling of the pipe parts and these lugs can be kept free from one another for decoupling of the pipe parts.
In other embodiments, the lugs of successive rows are offset in relation to one another in the tangential direction. In this embodiment, “intermediate steps” must be taken (rotation and further sliding in the axial direction) in order to arrive at a maximal engagement of the lugs of one pipe part on the lugs of the other pipe part. A drawback of these embodiments is that they are generally less easy to couple. An advantage is, of course, that they are also less easy to decouple. Furthermore, the axial forces are better distributed over the circumference of the pipe parts, which can benefit the structural strength of the coupling.
In a further embodiment, along the circumference of each pipe part a first row of lugs and at an axially displaced position a second row of lugs are provided, wherein each of the rows of lugs is designed to form alternately in the axial direction penetrable and impenetrable regions, and wherein the penetrable and impenetrable regions of the first row are provided at circumferentially displaced positions in relation to the positions of the regions of the second row; and wherein the lugs of the first and second pipe part are provided in such a way on respectively the outer circumference and inner circumference of the associated pipe part that the pipe parts can be slid one into the other.
It has been found that the strength of the known bayonet coupling is limited partly by the fact that, at the site of the penetrable regions, no transmission of the forces applied to the pipes, and thus also to the coupling, can take place. In the known types of bayonet couplings, these penetrable regions are additionally present along the greatest part of the coupling length in the circumferential direction (herein also referred to as the coupling circumference). This means that only a small part of the total circumference of the coupling can be used for the transmission of forces, and so the load on this part becomes large. The invention provides for the enlargement of the coupling length. The result is a coupling between two successive pipes, which coupling provides a good transmission of the axial forces arising on the pipes, since, over almost half of the circumference, coupling surfaces are present to absorb the forces.
A further advantage of the coupling is that both the coupling and decoupling of the pipes remains relatively simple. Coupling is realized by sliding the coupling parts into one another and decoupling is realized by sliding the coupling parts out of one another. Moreover, no moving parts need to be present in the coupling (though in certain embodiments the choice can be made to still construct the coupling with moving parts, for example for locking the coupling). A further advantage is that the coupling can be operated by displacement (for example in the axial direction and/or tangential direction) of the pipes on which the couplings are provided. In addition, the inner side of the pipe assembly can be made relatively smooth, which reduces the wear on the pipes, for example if it is a question of a downpipe along which relatively hard material, such as stone, is poured downwards.
In further embodiments, a coupling can be realized by first making a “crude” confinement by allowing the lugs of one lug to pass the first row (or a first set of rows), in which the penetrable regions of the other lug are relatively large and therefore the lugs of one lug can pass these regions relatively easily. After this, a second row (or set of rows) is passed, in which the penetrable regions have a narrower dimensional tolerance in relation to the lugs.
According to a further embodiment, the axial distance between the first and second row of lugs of a coupling is greater than the axial thickness of the lugs in order to procure a rotation space in which the lugs can be twisted in relation to one another.
In a further embodiment, the lugs comprise a number of lugs evenly distributed over the circumference of the tubular connecting element. Although such lugs are not evenly distributed over the circumference in all embodiments, the advantage of this embodiment is that, in a relatively large number of rotational positions, the lugs are arranged in relation to one another such that they can be slid through the penetrable regions. If the lugs are unevenly distributed over the circumference, it may sometimes be necessary to rotate the pipe parts precisely into one specific position in relation to one another to enable the lugs to be slid in. This can be advantageous if the pipe parts must be coupled in a specific position in relation to one another.
In further embodiments, the length in the circumferential direction of a lug forming an impenetrable region substantially conforms to the length in the circumferential direction of a space therebetween forming a penetrable region, so that the lug is able to pass through the penetrable region, yet a maximum possible contact surface for the transmission of forces is maintained when the lugs are twisted over one lug length. In other embodiments, the said length of the lug can be far smaller than the said space, so that the lug can pass through the space more comfortably.
According to one embodiment, the coupling comprises a locking element having at least one projection, which projection, in the coupled state, can be placed between the lugs of successive rows. A locking element of this type can be provided to block the mutual rotational movement of the pipe parts and thus maintain the state in which the pipe parts are fixed in relation to one another in the axial direction. This prevents the coupling from being possibly decoupled by unhoped-for twisting of a connecting element. More specifically, in certain embodiments in the coupled state empty spaces are present between the lugs of the first row of a first connecting element and the lugs of the second row of an opposite-situated, second connecting element. Such a projection can be placed in one or more of these spaces, so that the coupling can no longer be decoupled. In particular, the locking element comprises a locking ring, which can be slipped around one of the sockets. The locking ring can then be provided with one or more projections, which are designed and arranged such that they can be slid into one or more corresponding spaces.
In certain embodiments, for example when the pipe assembly is used to transport material from and to a bottom (sea bed), the pipes and couplings are made of steel or other material so as to be able to absorb the forces which arise. In other embodiments, the pipes can be made of composite material. The couplings themselves can consequently be made of composite material or of steel. Otherwise, the lugs can be separate parts which are fastened to a pipe or can be formed integrally with the pipe.
Further advantages, characteristics and details of the present invention will be clarified with the aid of the following description of some embodiments thereof. In the description, reference is made to the appended drawings, in which:
a-6e show schematic representations of the first embodiment according to the invention in different stages of the coupling activity; and
a-d and 9 show cross sections of further embodiments.
As herein described, the invention relates to the releasable coupling of pipes or pipe parts (herein referred to, in short, as pipe parts). The term “pipe parts” should here be interpreted broadly. For example, the pipe parts can be of a relatively inflexible variety or can even be of rigid construction, such as steel pipes, but flexible pipes may also be used. By the term “flexible” pipes should be understood hoses, pipelines, pipes or tubes, ducts and the like, which are made to be flexible to a greater or lesser degree.
In order to simplify the drawing, only a limited number of pipes 7 is represented. The pipe assembly is suitable for deep-sea applications.
The couplings 8 with which the pipes 7 placed one behind the other are connected to one another respectively comprise a first pipe part 9 fitted to a first pipe (for example an upper pipe 7) and a second pipe part 10 fitted to a second pipe 7′. Other embodiments are also possible of course, for example embodiments in which there are pipes which are only provided with first pipe parts 9 and other pipes which are only provided with second pipe parts 10.
Referring to
The second pipe part 10 similarly comprises a substantially cylindrical socket 12. The socket 12 is provided on the outer side with two rows 30, 31 of lugs in the form of lugs 24 and lugs 23 respectively. The first row 30 of lugs 24, just like the first row 18 of the first pipe part 9, is provided along the circumference of the socket 12, the row extending substantially transversely to the axial direction.
The lugs 13, 15 of the first pipe part 9 and the lugs 23, 24 of the second pipe part 10 all extend substantially transversely in relation to the axial direction. Between the lugs, respective penetrable regions 26, 25 are formed in respectively the first row 30 and second row 31 of the second pipe part 10, and penetrable regions 12, 14 in respectively the first row 18 and second row 19 of the first pipe part 9. The respective lugs 24, 23 in the first and second row 30, 31 and lugs 13, 15 in the first and second row 18, 19 form so-called impenetrable regions. An impenetrable region is a region in which, as a result of the presence of a lug, there is no room to slide the socket 11, 12 inwards. The axially inward sliding of one socket into the other can only be realized by positioning the lugs of the first row 30 of the second pipe part 10 in front of the penetrable regions 12 between the lugs 13 of the first row 18 of the first pipe part 9. This is represented in more detail in
Furthermore, the successive rows 18, 19 and rows 30, 31 are each arranged at a mutual distance apart, for example at a fixed distance (a). This distance (a) is greater than the thickness (d) of the lugs, which ensures that between rows 30 and 31 a rotation space 40 and between successive rows 18, 19 a rotation space 41 is created. These rotation spaces 40, 41 extend in the circumferential direction (transversely to the axial direction) and offer the possibility of twisting the lugs therein.
In use, one of the lugs, in the represented situation the upper pipe part 9, is displaced downwards from above (direction P1), so that the lugs 13 of the first row 18 of the socket 11 are slid via the penetrable openings 26 between neighbouring lugs 24 of the first row 30 of the socket 10 so as to end up in the first rotation space 40. This situation is represented in
After this, the first pipe part 9 is twisted somewhat (direction R1) into the position represented in
In the end position represented in
The decoupling of the coupling is realized by performing the above-described actions in the reverse order. It should here be noted that, since in the coupling process it does not matter in which direction (R1), i.e. to the left or right, a lug is rotated in relation to the other lug, this is likewise not the case in the decoupling process. In the decoupling, the lugs can therefore also be rotated in the same direction as in the coupling.
In
When the locking element 45 is brought into the situation represented in
This can be done, for example, by clamping the annular element 46 onto a bottom edge of the tubular element 12. In other embodiments, in which the first pipe part 9 is located below the second pipe part 10, the locking element 45 rests on the topmost pipe part and the locking element 45 shall remain held in the locked position under the influence of gravity. In such a situation, the fastening of the locking element 45 to the coupling can possibly be dispensed with.
In the embodiment of the locking element 45 which is represented in
The couplings as described above with reference to
As a result thereof, the axial load is no longer evenly distributed over the different lugs, but the load will increase along a first circumferential part of the pipe parts and decrease along a second circumferential part. The effective coupling length of the lugs is thus diminished. This effect reduces the strength of the coupling and causes extra wear along the first circumferential part.
A secondary adverse effect is that, under the influence of a varying lateral load, the pipes 7 can rotate in relation to one another. This is explained in greater detail below.
Under the influence of lateral load, two coupled-together pipes 7 can proceed to stand at an angle to one another. The two axial body axes of the two pipes 7 are then no longer parallel, but stand at a small angle a to one another (for example α≈1-3°. The direction of the lateral load can vary, as a result of which the angle a rotates, for example, to the left or right. It is also possible that, as a result of the wave motions of the water and resulting movement of the ship, the coupled pipes 7 proceed to move in relation to one another. Running waves can thus occur in the coupled pipes 7. The fact that the pipes 7 have mutually acquired a certain degree of freedom of movement prevents the herein arising forces from rising too high. As a result of this, the pipes 7 can proceed to move tangentially in relation to one another, that is to say proceed to rotate around the body axes, which can result in a diminished coupling or even an unwanted uncoupling.
The object of the here described embodiment is to eliminate or, at least, lessen these disadvantages.
a-8b show such an embodiment, in which a coupling for the releasable coupling of pipe parts is shown, the coupling comprising:
The pipe parts can have a typical diameter of, for example, 250-2000 mm, for example 732 mm. The contact surfaces 28 can be formed as part of a spherical surface, wherein the sphere associated therewith can have a radius of, for example, 0.5 to 2.5 times the diameter of the pipe parts. It is here noted that, because the centre points M for the contact surfaces 28 of the different rows of lugs coincide, the different rows have a different radius. Thus, in a pipe part of 732 mm diameter, the radius of the first row of lugs can be equal to 654 mm and that of the second row of lugs be equal to 813 mm.
The embodiments shown in
a and 8b show an embodiment wherein the lugs of successive rows are tangentially offset in relation to one another (analogously to
The lugs of the second pipe part 10 comprising a substantially cylindrical outer socket 11 are provided on the inner side of the socket 11 and comprise contact surfaces 28 of concave design. Because the centre points M for all contact surfaces 28 of all rows of lugs, which centre points are associated with the spherical surfaces, substantially coincide, it is clear that the contact surfaces 28 of the lugs 13 of the first row 18 (see
The lugs of the first pipe part 9 comprising a substantially cylindrical socket 12 are provided on the outer side of the socket 12 and comprise contact surfaces 28 of convex design. Because the centre points M for all contact surfaces 28 of all rows of lugs, which centre points are associated with the spherical surfaces, substantially coincide, it is clear that the contact surfaces 28 of the lugs 24 of the first row 30 are less strongly curved than the contact surfaces 28 of the lugs 15 of the second row 19.
The centre points M for all contact surfaces 28, which centre points are associated with the spherical surfaces, substantially coincide on an axial body axis of the respective first and second pipe part. This point is indicated in
c and 8d show a variant wherein the lugs of the second pipe part 10 comprising a substantially cylindrical socket are provided on the outer side of the socket and comprise contact surfaces 28 of convex design. The lugs of the first pipe part 9 comprising a substantially cylindrical outer socket are provided on the inner side of the socket and comprise contact surfaces 28 of concave design.
Of course, the embodiment shown in
However, this can also be realized the other way round, analogously to
The embodiments shown in
The shown and discussed embodiments relate to pipe parts which are suspended one from another, wherein pipe parts hang from a pipe part located directly above them. Of course, the highest pipe part hangs from a vessel, for example. Naturally, embodiments in which the pipes are stacked, that is to say that the pipe parts lean on a pipe part located directly below them, are also possible. The bottommost pipe part can rest on the bottom.
The present invention is not limited to those embodiments thereof which are herein described. The described coupling can be used in a number of fields outside the described maritime examples. The applied-for rights are rather defined by the following claims, within whose scope a variety of applications and modifications are conceivable.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2004010 | Dec 2009 | NL | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/NL2010/050845 | 12/14/2010 | WO | 00 | 8/14/2012 |
| Number | Date | Country | |
|---|---|---|---|
| 61289769 | Dec 2009 | US |
