Plug apparatus

A disintegrable plug apparatus for use in connection with petroleum wells, especially during pressure testing of such petroleum wells. The plug apparatus has an outer housing surrounding at least one sealing device and a plurality of supporting bodies, where at least one of the supporting bodies is in engagement with a locking device for locking to a locking sleeve. After application of a predetermined pressure on the plug apparatus, the at least one supporting body and the at least one sealing device are permitted an axial movement such that the at least one sealing device is brought into contact with loading devices for disintegration of the at least one sealing device.

The present invention relates to a disintegratable plug apparatus for use in connection with petroleum wells, and in particular for use during pressure testing of such petroleum wells.

In the oil industry it is known that different types of plugs are used during pressure testing of petroleum wells, for example, before start-up of production from the well, or when extensive maintenance of the well has been carried out. A plug will then be installed in the well, after which an area of the well will be pressurised, so as to check that pipe joints, packers, valves etc. are properly installed, and whether they are also leak-tight. The plug is usually installed as a lower part of a production tubing, the plug then being arranged in a pipe element that is designed to be connected with one or more pipe elements forming the production tubing. The plug may also be arranged in an independent pipe element which will then be capable of being run down inside a liner or a casing, the liner or casing being installed in the well beforehand.

Once the pressure testing has been completed and production is to start up, the plug must be removed from the well, either by the plug being retrieved or by the whole or parts of the plug being destroyed downhole.

Such plugs comprise an outer housing, in which outer housing is arranged one or more elements that will prevent a fluid flow across the plug.

Plugs that are to be retrieved from the well may be connected to a wire (wireline) or the like, whereby the wire is used to retrieve the plug. Such plugs might, however, become wedged during retrieval or, in particular if downhole for a long time, they might have reacted with the tubing in which, for example, they are arranged, and so become stuck, which means the plugs are difficult or even impossible to bring up to the surface again.

For the above reasons, so-called destructible plugs have been developed, where the plug remains in the well, but where parts of the plug are destroyed such that a fluid flow is permitted across the plug. Such destructible plugs are made of one or more materials that will dissolve when the material/materials come into contact with a liquid, for example, a chemical or water. For instance, such a plug may be made of a rubber material, this rubber material being brought into contact with the well fluid or the chemical once testing of the well has been carried out, so as to dissolve the rubber material.

However, during operations from floating rigs, this method will be far too unreliable and slow, seen in the light of the operating costs for such a platform. In this case, it will not be possible to predict the exact time at which the plug is removed and passage through the well opens.

Such destructible plugs can also be made of a material that can be broken up or crushed by using explosives or mechanical loading devices, where this material, for example, may be of glass, ceramics or the like. Use of explosives will provide a sure removal of the plug, but will be a safety risk, and there are also many countries that have stringent requirements regarding the use and import of explosives. Mechanical loading devices are often highly complex and thus prone to faults.

It is therefore an object of the present invention to provide a plug apparatus that will provide a safe and reliable destruction of the plug apparatus.

These objects are achieved by a plug apparatus according to the attached claims, with further details of the invention set forth in the description below.

The present invention relates to a plug apparatus for carrying out tests in a petroleum well, a pipe or a borehole, the plug apparatus comprising an outer housing with a throughgoing axial bore surrounding at least one sealing device supported by a plurality of supporting bodies arranged in the throughgoing axial bore, where at least one of these supporting bodies is in engagement with a locking device for locking to a locking sleeve or a retaining sleeve and a locking ring. The at least one supporting body will, after an application of a predetermined pressure to the locking ring, be brought out of engagement with the locking device, thereby resulting in the at least one supporting body and the at least one sealing device being permitted an axial movement in the throughgoing axial bore, this axial movement causing the at least one sealing device to be brought into contact with loading devices that are designed to subject the at least one sealing device to load, so as to produce disintegration of the at least one sealing device.

One or more sealing elements may be disposed between the supporting bodies and the sealing device(s), so as to provide a leak-tight connection between them.

The plug apparatus according to the present invention may thus comprise the use of one, two, three or even more sealing devices, where a sealing device, for example, may be made of a glass material, a ceramic material or the like. It should further be understood that if several sealing devices are used in the plug apparatus, the sealing devices can be made of different material.

The sealing devices may be made in a form that is circular, polygonal etc.

The loading devices used to subject the at least one sealing device to load so as to produce a weakness of the sealing device may be in the form of one or more pin devices, spikes, blades or the like, the loading devices being suitably configured to provide substantial point loading, cutting or scratching of the sealing devices, so that the sealing devices may be more easily disintegrated.

In an embodiment of the present invention, the outer housing and one or more of the supporting bodies will then be configured with one or more recesses and/or bevelled edges for receiving the loading devices in the form of pin devices or spikes, which loading devices are adapted to subject the at least one sealing device to point loading, the recesses and/or the bevelled edges allowing the loading devices to rotate or turn in towards a centre axis in the plug apparatus on the axial movement of the supporting bodies and the at least one sealing device, so as to be able to subject the at least one sealing device to point loading.

In another embodiment of the present invention, the loading devices in the form of blades or the like will be fixedly connected to a ring element and arranged in such a way that the at least one sealing device, on being moved past the loading devices, will be cut or scratched over at least a part of the sealing device.

It should be understood that the plug apparatus according to the present invention can comprise a plurality of such loading devices which, in that case, will be arranged around the throughgoing axial bore in the outer housing. In an embodiment, the plug apparatus may comprise three such loading devices for each sealing device, which loading devices can be arranged offset 120 degrees relative to one another. However, it will be understood that more such loading devices can be used, the loading devices in that case being arranged offset differently relative to each other.

The plug apparatus can also comprise a plurality of sealing elements, which sealing elements can be arranged between the throughgoing axial bore in the outer housing and the supporting bodies and/or between the supporting bodies and the at least one sealing device.

The locking device that is used to provide locking between at least one supporting body and the locking sleeve may be formed of at least one ball, roller, pawl, shear pin or similar elements. The locking device can also be formed of a plurality of shear pins that are arranged to provide locking between at least one supporting body and the locking sleeve, whereby the shear pins after a certain load will be broken so as to release the at least one supporting body from the locking sleeve.

The at least one sealing device can in an embodiment be configured with bevelled upper and lower edges, which bevelled edges are arranged between the side edges and the upper/lower surfaces of the sealing device.

In an embodiment, one or more of the supporting bodies may be configured with one or more axial channels around their circumference, in which channel or channels a movable member is arranged. The movable member or members are used to bring the plug apparatus into its open position, whereby fluid is allowed to flow across the plug apparatus. This can be achieved in that a force is applied to the body or bodies, whereby the body or bodies, when displaced axially, will bring a locking ring or a retaining sleeve out of engagement with the locking devices, so as to allow that at least one sealing device is brought into contact with one or more loading devices.

Thus, the present invention provides a plug apparatus which disintegrates completely and where the plug apparatus gives far greater flexibility as regards structure, use and safety of such plug apparatuses.

To facilitate the understanding of the structure and operating principle of a plug apparatus1according to the present invention, the plug apparatus1according to the present invention is shown in the figures with one or two sealing devices3, but these illustrated embodiments should not be interpreted as limiting embodiments.

Thus, a person of skill in the art will understand that the plug apparatus1according to the present invention can be made with just one sealing device3, two sealing devices3or even more than two sealing devices3, the number of sealing devices3depending on different parameters in the petroleum well, for example, pressure and temperature, safety etc.

A closed state of the plug apparatus should, according to the present invention, be understood to be a state in which fluid cannot flow across the plug apparatus, whilst an open state of the plug apparatus should be understood to be a state in which fluid can flow across the plug apparatus.

FIG. 1Ashows a cross-section of a first embodiment of a plug apparatus1according to the present invention in a closed state, where the plug apparatus1comprises an outer housing2that is configured with a throughgoing axial bore A, in which axial bore A a sealing device3is arranged. The outer housing2may be a pipe element which by means of threads, rapid couplers or the like (not shown) can be connected to a pipe string or even be a separate element.

Alternatively, the plug apparatus1according to the present invention can be configured to be arranged in a pipe section (not shown), which pipe section is then configured to be connectable to one or more pipe sections, so as to, for example, form a production tubing or a pipe string in a petroleum well. The plug apparatus1may also conceivably be configured to be arranged in an independent pipe element, so as to be run down inside a liner or a casing, the liner or casing being installed in the well beforehand.

The sealing device3may be made of a glass material, a ceramic material or the like, the sealing device3being treated so as to be able to withstand high pressures and temperatures, but crushed when subjected to a certain load.

The axially throughgoing bore A in the outer housing2may be configured with a recess (not shown), in which recess two supporting bodies4,6are arranged. However, it should be understood that the supporting bodies4,6may also be arranged in the axially throughgoing bore A without the axially throughgoing bore A being configured with a recess. A person of skill in the art will know how this can be done, and therefore it is not further described herein.

The supporting bodies4,6are preferably annular, and are designed to hold the sealing device3in place in the outer housing2when the plug apparatus1is assembled and in its closed state. The sealing device3will preferably also be annular.

The axially throughgoing bore A (i.e., the inside of the outer housing2) is further configured with a plurality of recesses or grooves for receiving sealing elements15a, the recesses or grooves extending around the circumference of the axially throughgoing bore A. This will mean that a fluid-tight connection is formed between the outer housing2and the supporting bodies4,6. Similarly, the supporting body4, on a side facing the sealing device3, will be configured with recess(es) or groove(s) for receiving sealing element15b, the recess(es) or groove(s) extending around the inner circumference of the annular supporting body4, so that a fluid-tight connection is also formed between the sealing device3and the supporting body4.

The supporting body4across a first part4aof its height is configured with a thickness or breadth B and across a second part4bof its height is configured with a thickness or breadth b, the first and the second part4a,4bbeing connected to each other by means of a bevelled portion4c. The supporting body4will be arranged above the supporting body6and abutting or bearing against the supporting body6when the plug apparatus1is assembled.

When the plug apparatus1according to the present invention is assembled, the bevelled portion4cof the supporting body4will bear against a bevelled edge3aof the sealing device3, whilst the other part4bof the supporting body4will then bear against a side edge3bof the sealing device3.

The supporting body6is at an end configured with two bevelled edges6a,6b, so as to form an “apex” in the supporting body6, where the bevelled edge6awill rest against the bevelled edge3aof the sealing device3. The other bevelled edge6bof the supporting body6will extend down from the apex to an outside of the supporting body6which abuts against an inner surface of the outer housing2. At an opposite end to the bevelled edges6a,6b, the supporting body6is configured with a recess6cso as to form a projection6din the supporting body6.

Below the supporting body6, at a distance therefrom, a locking sleeve7is arranged in the axial bore A. The locking sleeve7is suitably fixedly connected to the outer housing2and is further configured with a recess7aso as to form a projection7bin the locking sleeve7. The projection7bis further configured with a bevelled edge7cthat extends down from the inside of the locking sleeve7to an outside of the locking sleeve7which abuts against an inner surface of the outer housing2.

The recesses6c,7ain the supporting body6and the locking sleeve7will be so configured as to form a space or gap8between the outer housing2and the projections6d,7bwhen the plug apparatus1is assembled.

The projections6d,7bare shown with different thickness or breadth, but it should be understood that they also could be made of the same thickness or breadth.

In the space or gap8formed between the outer housing2, the supporting body6projection6dand the locking sleeve7projection7b, a locking ring9is arranged, which locking ring9in a side facing the projections6d,7bis configured with a recess9b.

Between the locking sleeve7recess7band the lower supporting body6projection6dthere is arranged a locking device10in the form of a ball, a roller or an element, which locking device10abuts against the locking ring9when the locking ring9is arranged in the space or gap8between the outer housing2and the projections6d,7bof the supporting body6and the locking sleeve7.

When the plug apparatus1according to the present invention is assembled and is in a closed state, the bevelled portion6aof the supporting body6will bear against the bevelled edge3aof the sealing device3, whilst the bevelled portion6bwill rest against a plurality of recesses11formed in the axially throughgoing bore A in the outer housing2.

In each of these recesses11is arranged a loading device12, for example, in the form of a pin or spike device, the loading device12being so configured that a part of the loading device12will be received in the recess11in the outer housing2, whilst the rest of the loading device12will rest against the bevelled edge6bof the supporting body6. Because of the bevelled edge6b, the loading devices12will not be in contact with the sealing device3when the plug apparatus1is in its closed state.

In this embodiment of the plug apparatus1, three such loading devices12(only one is shown) are provided around an outer circumference of the sealing device3, the loading devices12being arranged offset 120 degrees relative to one another.

However, it will be understood that more such loading devices12can be used, the loading devices12in that case being arranged offset differently relative to each other.

A channel B is formed through the supporting bodies4,6, in which axial channel B a movable member13is arranged. When the plug apparatus1is assembled, the movable member13will abut against an upper side of the locking ring9(seeFIG. 1B). In this embodiment of the plug apparatus1, three such members13(only one is shown) are arranged around an outer circumference of the sealing device3, the members13being arranged offset 120 degrees relative to one another. The members13are used to bring the plug apparatus1into its open state, whereby fluid is allowed to flow across the plug apparatus1. This will be explained in more detail in relation to the other embodiments of the plug apparatus1.

To protect the different elements of the plug apparatus1from the well fluid when the plug apparatus1has been run down into the petroleum well, a membrane22is connected to a lower end of the locking sleeve7. The space formed between the sealing device3and the membrane22can then be filled with an oil, silicon grease or the like. Such an arrangement including membrane and oil, silicon grease or the like can also be provided on an upper side of the plug apparatus, and a person of skill in the art will understand how this is to be done.

Through the design of the plug apparatus1described above, the supporting bodies4,6and the sealing device3will be secured in their position by the locking sleeve7, the locking ring9and the locking device10.

FIG. 1Bis an enlarged view of detail J (left-hand side of the plug apparatus1shown inFIG. 1A) whilstFIG. 1Cis an enlarged view of detail K (right-hand side of the plug apparatus1shown inFIG. 1A).

FIG. 2Ashows a cross-section of a second embodiment of a plug apparatus1according to the present invention in a closed state, where the plug apparatus1comprises an outer housing2, in which outer housing2are arranged two sealing devices3. The outer housing2may, for example, be a pipe element that can be connected to a pipe string or be an independent element.

Each sealing device3can be made of a glass material, a ceramic material or the like. If several sealing devices3are used in the plug apparatus1according to the present invention, the sealing devices3can be made of different material.

The outer housing2, on an inside, is configured with an axially throughgoing bore A, in which recess supporting bodies4,5,6are arranged. The supporting bodies4,5,6, which preferably are annular, are designed to hold the sealing devices3in place in the outer housing2when the plug apparatus1is assembled.

To obtain a leak-tight connection between the inner surface of the outer housing2and the supporting bodies4,5,6, a plurality of sealing elements15aare disposed between the outer housing2and the supporting bodies4,5,6. In this case, either the supporting bodies4,5,6or the outer housing2can be configured with grooves or slots for receiving the sealing elements15a.

The supporting body4will then constitute an upper supporting body for the upper sealing device3, whilst the supporting body6will constitute a lower supporting body for the lower sealing device3. Between the upper supporting body4and the lower supporting body6is arranged a middle supporting body5, which middle supporting body5is configured with a projection5a. The supporting body5projection5awill then be designed to cooperate with the bevelled edges3aof a sealing device3so as to ensure that each sealing device3is arranged properly in relation to the supporting body5. The supporting body5is further configured with a bevelled upper edge5b, which bevelled edge5bwill extend down from an inside of the supporting body5which rests against the side edge3aof the sealing devices3to an outside of the supporting body5which abuts against an inner surface of the outer housing2.

The upper supporting body4is also designed to bear against a bevelled edge3aof the sealing device3, the supporting body4over a first part4aof its height being configured with a thickness or breadth B and over a second part4bof its height being configured with a smaller thickness or breadth b, wherein the first and the second part4a,4bare connected to each other by means of a bevelled portion4c. When the plug apparatus1is assembled, the bevelled portion4cand the second part4bof smaller thickness or breadth b will rest against the bevelled edge3aand side edge3bof the sealing device3.

The lower supporting body6will at an end be configured with two bevelled end edges6a,6b, so as to form an “apex” in the supporting body6, where one of the bevelled edges6awill abut against the bevelled edge3aof the sealing device3. The other bevelled edge6bwill extend down from the apex to an outside of the supporting body6which rests against an inner surface of the outer housing2. At an opposite end to the bevelled end edges6a,6b(the apex), the supporting body6is configured with a recess6cso as to form a projection6din the supporting body6.

Below the lower supporting body6, at a distance therefrom, a locking sleeve7is provided internally in the housing2. The locking sleeve7is suitably connected to the inner surface of the outer housing2and is further configured with a recess7ato form a projection7bin the locking sleeve7. The locking sleeve7projection7bis further configured with a bevelled edge7cthat extends down from an inside of the locking sleeve7to an outside of the locking sleeve7which rests against an inner surface of the outer housing2.

The recesses6a,7ain the lower supporting body6and the locking sleeve7will be so configured that a gap8is formed between the outer housing2and the projections6d,7bwhen the plug apparatus1is assembled.

In an embodiment, the projections6d,7bhave a different thickness, but they can also be configured with the same thickness.

In the space8formed between the outer housing2and the projection6dof the lower supporting body6and the projection7bof the locking sleeve7, a locking ring9is provided, which locking ring9in a side facing the projections6d,7bis configured with a recess9b.

Between the locking sleeve7and the lower supporting body6there is arranged a locking device10in the form of a ball, a roller or an element, which locking device10rests against the locking ring9when the locking ring9is arranged in the gap8between the outer housing2and the projections6d,7bof the supporting body6and the locking sleeve7.

Each of the bevelled edges5b,6bof the middle supporting body5and the lower supporting body6will, when the plug apparatus1is assembled, abut against and be aligned with a recess11formed on the inner surface of the outer housing2. In each of these recesses11is arranged a loading device12, for example, in the form of a pin or spike device, the loading device12being so configured that a part of the loading device12will be received in the recess11in the outer housing2, whilst the rest of the loading device12will rest against the bevelled edges5b,6bof the middle and the lower supporting bodies5,6. Because of the bevelled edges5b,6b, the loading devices12will not be in contact with the sealing devices3in this position of the plug apparatus1.

In this embodiment of the plug apparatus1according to the present invention, three such loading devices12(only one is shown) are arranged around an outer circumference of each sealing device3, the loading devices12being arranged offset 120 degrees relative to one another. However, it should be understood that the loading devices12can be offset differently relative to each other.

To protect the different elements of the plug apparatus1from the well fluid when the plug apparatus1has been run down into the petroleum well, a membrane22is connected to a lower end of the locking sleeve7. The gap formed between the sealing device3and the membrane22can then be filled with oil, silicon grease or the like.

Through the design of the plug apparatus1described above, the supporting bodies4,5,6and the sealing devices3will be secured in their position by the locking sleeve7, the locking ring9and the locking device10.

InFIG. 2B, which is an enlarged view of detail O of the plug apparatus1shown inFIG. 2A, it is seen that a force F has been applied to the body13(only the one body13is shown in the figures), the body13having pushed the locking ring9down into the gap8. The locking ring9has been pushed so far down that the recess9bwill be aligned with the locking device10. The locking device10here has not yet been pushed into the recess9b, but will, because of the bevelled edge7cof the locking sleeve and the force transferred from the well fluid that is on the upper side of the upper sealing device3, through the sealing devices3and the supporting bodies4,5,6to the locking device10, be pushed out of the recess9bin the locking ring9.

Because of the bevelled edge7cof the locking sleeve7and the weight of fluid that rests on the upper side of the upper sealing device3, which weight is transferred from the sealing devices3to the supporting bodies4,5,6, the locking device10has inFIG. 3Abeen forced radially outwards into the recess9bof the locking ring9. This means that the support of the lower supporting body6is removed (the locking device10is forced out into the recess9bof the locking ring9), whereby the sealing devices3and the supporting bodies4,5,6, on being subjected to the weight of the fluid, will be moved a distance axially downwards in the outer housing2, towards the locking sleeve7so as to be brought into abutment with the locking sleeve7, The axial distance the sealing devices3and the supporting bodies4,5,6move will correspond to the height of the locking device10.

InFIGS. 3B and 3Cit is seen that the axial movement of the sealing devices3and the supporting bodies4,5,6towards the locking sleeve7has caused the loading devices12, arranged between the supporting bodies4,5and the supporting bodies5,6to follow this axial movement together with the sealing devices3and the supporting bodies4,5,6. The loading devices12will thus be “rotated” about the recesses11in the outer housing2and in towards a centre axis S in the plug apparatus1, so as to be brought into contact with the seals3. When the seals3and the supporting bodies4,5,6have moved such that the lower supporting body6has been brought into engagement with the locking sleeve7, the loading devices12will have “rotated” so much that they will be perpendicularly arranged on the side edges3bof the sealing devices3, which will give such large point loading on the sealing devices3that they will break open. The load of the weight of the fluid that lies on the upper side of the upper sealing device3will then first cause the sealing devices3to bend or sag a little before they disintegrate.

As stated above, three such loading devices12will be arranged around the circumference of each sealing device3, thereby facilitating the disintegration of the sealing devices3and also ensuring that each sealing device3disintegrates completely. The loading devices12in the form of spikes or pin devices will then, for example, be arranged offset 120 degrees relative to one another. A person of skill in the art will however understand that the plug apparatus1according to the present invention could be made having fewer or more such loading devices12, and that the loading devices12may be offset differently relative to each other.

The loading devices12will further be configured to produce greatest possible load on the side edges3bof the sealing device3, for example, with a tapered or pointed configuration at one end which provides the point loading on the side edges3bof the sealing devices3.

FIG. 3Ashows in an exaggerated manner how the sealing devices3bend or sag with the intention of illustrating the load they are subjected to; however, the sealing devices3will disintegrate before they have reached such a degree of bending or sagging.

FIG. 4Ashows a second embodiment of a plug apparatus1in its closed state according to the present invention, where the plug apparatus1, to facilitate the understanding of the structure and operating principle of the plug apparatus1, is presented with two sealing devices3. The plug apparatus1according to this embodiment may thus comprise only one sealing device3, or also more than two sealing devices3.

The plug apparatus1comprises an outer housing2with an axial throughgoing bore A, so as to be able to receive an upper supporting body4and a ring element17in the axially throughgoing bore A. When the plug apparatus1is assembled, two sealing devices3will be disposed between the upper supporting body4and the retaining sleeve14arranged below. The retaining sleeve14will then be arranged on an inside of the ring element17.

Each sealing device3is configured with four bevelled edges3a, when seen in cross-section, formed between the side edges3band upper and lower surfaces3cof the sealing device3, so as by means of the bevelled edges3aand side edges3bto form retaining surfaces against the upper supporting body4and the retaining sleeve14.

The upper supporting body4is designed to rest against the bevelled edges3aand side edge3bof the sealing device3, the upper supporting body4over a first part4aof its height being configured with a thickness or breadth B, whilst the upper supporting body over a second part4bof its height is configured with a smaller thickness or breadth b, the first and the second part4a,4bbeing connected to each other by a bevelled portion4c.

When the plug apparatus1according to the present invention is assembled, the upper supporting body4will abut against a ring element17arranged therebelow, which ring element17will abut against a locking sleeve7arranged therebelow. The locking sleeve7will then be suitably fixedly connected to the inner surface of the outer housing2. The locking sleeve7is further configured with a recess7awhich will form a projection7bin the locking sleeve7, in which projection7bthree through openings7dare formed. This will mean that a gap8is formed between the outer housing2, the ring element17and the locking sleeve7projection7b, in which gap8a locking ring9is arranged.

To produce disintegration of the plug apparatus1sealing devices3, the plug apparatus1also comprises a loading device12, for example, in the point of a blade arrangement, which loading device12, via two bolts18or the like, is connected to the ring element17. The loading device12will on a side facing the sealing devices3be configured at least over a part of its height with sloping edge12a, which sloping edge12aslopes downwards and outwards towards a centre axis S in the plug apparatus1. In the side facing the inner surface of the outer housing2, the loading device12is configured with a vertical edge, such that the loading device12can be arranged against the inner surface of the outer housing2. This embodiment of the loading device12will mean that the sealing devices3will be subjected to increasing load as they are moved past the loading device12. The loading device12will then extend in towards a centre axis S of the plug apparatus1with a width that results in at least a part of the bevelled edge3aand side edge3bof the sealing devices3being subjected to a cutting open or scratching by the loading element12.

Preferably, three such loading devices12are arranged around the inner circumference of the outer housing2, the loading devices12being, for example, arranged offset 120 degrees relative to one another. However, it should be understood that fewer or more such loading devices12can be used, and the loading devices12can be offset differently relative to each other.

The retaining sleeve14will also be configured with a bevelled end edge14athat is adapted to abut against the bevelled edge3aof the lower sealing device3when the plug apparatus1is assembled, so as to form a support for the sealing devices3and the upper supporting body4. The bevelled edge14awill extend downwards from an outside of the retaining sleeve14and towards an inside of the retaining sleeve14.

The retaining sleeve14, at the opposite end to the bevelled edge14a, in an end area on its exterior, is configured with three recesses14b, which recesses14bare arranged spaced apart. Each of the recesses14bis further designed to be able to receive a part of a locking device10in the form of a ball, a roller, pawl or an element, so as to form a locking to the locking sleeve7which is arranged on the outside of the retaining sleeve14. The locking sleeve7will then be configured with three through openings7dfor receiving a part of the locking devices10.

The locking ring9will then be configured with three recesses9ain a side facing the locking sleeve7projection7b.

It should be understood that more or fewer than the three locking devices mentioned above may be used, the locking sleeve7and the locking ring9then being configured with as many through openings7dand recesses9a.

When the plug apparatus1according to the present invention is assembled, the recesses14ain the retaining sleeve14and the through openings7din the locking sleeve7projection7bwill be so arranged as to be aligned with each other, such that the recesses14ain the retaining sleeve14will receive a part of the locking devices10, in the same way as the through openings7din the locking sleeve7projection7bwill receive a part of the locking devices10. The retaining sleeve14and the locking sleeve7will then be locked to each other in this position, the locking ring9that is arranged in the gap8between the retaining sleeve14and the inner surface of the outer housing2preventing the locking devices10from moving radially outwards to the sides. The recesses9ain the locking ring9will then be arranged in such a way that each recess9ais arranged above its associated through opening7din the locking sleeve7projection7b.

Through the design of the plug apparatus1described above, the sealing devices3and the retaining sleeve14will be “hanged off” and are secured in position by the locking sleeve7, the locking ring9and the locking devices10.

FIG. 4Bshows a plug apparatus1according to the present invention as it is activated to be brought into an open state (i.e., prior to a disintegration of the plug apparatus1), where the locking ring9is subjected to a force F from a body13(not shown inFIG. 4B) arranged in a bore B (not shown inFIG. 4B) in the outer housing2, the bore extending in the longitudinal direction of the plug apparatus1. When the locking ring9is subjected to this force F, the locking ring9will be pushed so far down that the recesses9ain the locking ring9will be aligned with the through openings7dprovided in the locking sleeve7projection7b. Due to the weight of the fluid that lies on an upper side of the upper sealing device3, which weight is transferred from the sealing devices3to the retaining sleeve14, the locking devices10will be forced radially out of the recesses14bin the retaining sleeve, through the through openings7din the locking sleeve7and into the locking ring9recesses9a. This means that the support of the retaining sleeve14is removed, whereby the sealing devices3and the retaining sleeve14, on being subjected to the weight of the fluid, will move a distance axially downwards in the outer housing2, towards a receiving part16for the retaining sleeve14.

FIG. 4Bfurther shows that the retaining sleeve14and the sealing devices3have moved a distance downwards in the outer housing2, this downward movement having resulted in the lower sealing device3almost having been moved right past the loading device12(only one loading device12is shown), whereby this sealing device3has been cut open or scratched.

FIG. 4Cshows that the retaining sleeve14and the sealing devices3have moved a further distance downwards in the outer housing2, this downward movement having resulted in also the upper sealing device3almost having been moved right past the loading device12, whereby this sealing device3is in the process of being completely cut open or scratched.

FIG. 4Dshows that the retaining sleeve14and the sealing devices3have moved to a position in which the retaining sleeve14has come into abutment against the receiving part16, whereby both sealing devices3have been moved across and past the loading device12, which has resulted in the sealing devices3being weakened. The load of the weight of the fluid that lies on an upper side of the upper sealing device3will then cause the sealing devices3to disintegrate.

FIG. 4Eshows in an exaggerated manner how the sealing devices3bend or sag with the intention of illustrating the load they are subjected to; however, the sealing devices3will disintegrate before they have reached such a degree of bending or sagging.

FIG. 5shows a cross-section of the plug apparatus1according toFIGS. 1A-1Cin its open state, where it can be seen that the locking ring9, as a result of an influence of the body13, has been pushed downwards in the plug apparatus1, such that the locking device10has been pushed out into the locking ring9recess9b. Since the locking device10has been pushed out into the recess9b, this has allowed the lower supporting body6to be brought into contact with the locking sleeve7, whereby the sealing device3and the upper supporting body4have followed the movement of the lower supporting body6. The movement of the upper supporting body4has also resulted in the loading devices12(only one is shown) having been rotated in the recesses11in towards the centre axis S, so as to subject the sealing device3to load, thereby causing the sealing device3to have been crushed. Fluid is now able to flow through the plug apparatus1.

Similarly,FIGS. 6 and 7show a cross-section of the plug apparatus1according toFIGS. 2A-3BandFIGS. 4A-4D, when the plug apparatus1has been brought into its open position.

FIG. 8shows a cross-section of a fourth embodiment of the plug apparatus1in its closed position according to the present application, the plug apparatus1comprising an outer housing2with a throughgoing axial bore A, so as to be able to receive an upper supporting body4and a ring element17in the recess. When the plug apparatus1is assembled, two sealing devices3will be disposed between the upper supporting body4and a retaining ring (locking ring)14that is arranged within the ring element17.

Each sealing device3is configured with four bevelled edges3a, formed between the side edges3band upper/lower surfaces3cof the sealing device3, so as by means of the bevelled edges3aand side edges3bto form retaining surfaces against the upper supporting body4and the retaining sleeve14.

The upper supporting body4is designed to abut against the bevelled edges3aand side edge3bof the sealing device3, the upper supporting body4over a first part4aof its height being formed with a thickness or breadth B, whilst the upper supporting body4over a second part4bof its height is configured with a smaller thickness or breadth b, the first and the second part4a,4bbeing connected to each other by means of a bevelled portion4c.

The upper supporting body4will abut against the ring element17arranged therebelow, which ring element17in turn will abut against a locking sleeve7arranged therebelow. The locking sleeve7will be suitably fixedly connected to the inner surface of the outer housing2. The locking sleeve7is further configured with a recess7athat will form a projection7bin the locking sleeve7, in which the projection7bthree through openings7dare formed.

To produce disintegration of the plug apparatus1sealing devices3, the plug apparatus1also comprises a loading device12, for example, in the form of a blade arrangement, which the loading device12, via two bolts18or the like, is connected to the ring element17. The loading device12will, on a side facing the sealing devices3, be configured at least over a part of its height with a sloping edge12a, which sloping edge12aslopes downwards and outwards towards a centre axis S in the plug apparatus1. In the side facing the inner surface of the outer housing2, the loading device12is configured with a vertical edge, such that the loading device12can be arranged against the inner surface of the outer housing2. This configuration of the loading device12will mean that the sealing devices3will be subjected to increasing load as they are moved past the loading device12. The loading device12will then extend in towards a centre axis S of the plug apparatus1with a width that means that at least a part of the bevelled edge3aand side edge3bof the sealing devices3are subjected to a cutting open or rupturing by the loading device12.

The retaining sleeve (locking ring)14will also be configured with a bevelled end edge14awhich is adapted to rest against the bevelled edge3aof the lower seal3when the plug apparatus1is assembled so as to form a support for the seals3and the upper supporting body4. The bevelled edge14awill extend downwards from an outside of the retaining sleeve14towards an inside of the retaining sleeve (locking ring)14.

The retaining sleeve (locking ring)14is at an opposite end to the bevelled end edge14a, in an end area and on its outer surface configured with three recesses14b, the recesses14bbeing arranged spaced apart.

When the plug apparatus1is assembled, the recesses7din the locking sleeve and the recesses14bin the retaining sleeve14will be aligned.

The retaining sleeve14and the locking sleeve7will thus be connectable to plurality of locking devices10, these locking devices10, for example, being in the form of shear pins.

Through the design of the plug apparatus1described above, the upper supporting body4, the sealing devices3and the retaining sleeve14will “depend from” and be secured in position by the locking sleeve7and the locking devices10.

The plug apparatus1is brought into its open state by applying pressure on the upper side3cof the upper sealing device3, whereby this will result in the retaining sleeve14subjecting the locking devices10to a load. After the locking devices10have been loaded above a predetermined value, the locking devices10will give way, whereby the retaining sleeve14and the sealing devices3are no longer supported by the locking sleeve7. This will result in the sealing devices3being moved down towards the loading device12, so as to be cut open or scratched.

When the retaining sleeve (locking ring)14and the sealing devices3have moved to a position in which the retaining sleeve14has come into contact with a receiving part16, both sealing devices3will have been passed over and past the loading device12, which has caused the sealing devices3to be weakened. The load of the weight of the liquid that lies on the upper side3cof the upper sealing device3will then cause the sealing devices3to disintegrate.

FIG. 9shows a cross-section of the plug apparatus1according toFIG. 8in its open state, where it can be seen that the retaining sleeve (locking ring)14, as a result of the effect of the fluid above the upper sealing device3, has been released from the locking sleeve7in that the locking devices10have been cut, whereby the sealing devices3have been moved across and past the loading device12so as to be disintegrated.

Fluid may now flow through the plug apparatus1.

The present invention has now been explained with reference to exemplary embodiments, but a person of skill in the art will understand that changes and modifications could be made to these exemplary embodiments which are within the scope of the invention as defined in the following claims.