Abstract:
A method and a device for interrupting or reducing a media flow through a tubular pipe, involving removal of two opposed circumferential wall portions of the tubular pipe by means of two mainly parallel pistons, thereafter moving a third piston mainly mutually perpendicularly to the direction of travel for the pistons parallel piston and the length axis of the tubular pipe to a position mainly extending through the parallel pistons, the tubular pipe and the opposed openings of same, the third piston means being arranged with expanding devices, which, after completed movement of the third piston, are expanded to reduce, or interrupt, the internal cross-sectional area of the tubular pipe.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a method to interrupt a media flow through a tubular pipe and a device for utilizing the method. 
     It is previously known to use various types of valve means to reduce or interrupt a media flow through a tubular pipe. However, these valve means can only be attached to the pipe when the pipe is installed, or, when the pipe is not being utilized for transport of a media flow, unless the type of medium and flow and pressure conditions permit leakage during the time when a portion of the pipe is removed and replaced by a valve means, attached to the pipe as replacement for the removed portion. Such a method can only be utilized in cases involving relatively low pressure and flow speeds, and when the type of medium and the environment permits use of a method involving leakage. Furthermore, such a method of installation is obviously extremely difficult to perform. 
     OBJECT OF THE INVENTION 
     The object of the present invention is to disclose a method, and a device for utilizing the method, whereby it is possible to reduce or interrupt a continuous media flow through a pipe, regardless of the type, pressure and speed of flow for the medium. The interruption is also achieved in a minimum of time, effectively, completely without leakage, and the point of interruption can be chosen at random and without preventing the pipe from being used for the intended purpose, i.e. in cases where it is desirable to achieve a temporary interruption of the flow. It is easily realized, that the method and the device according to the present invention thus provides for an extremely large demand, e.g. to accomplish interruption of a media flow such as oil and/or gas leaking from pipe lines connected to maritime oil rings. It is thus possible to prevent damage caused by leakage, and also to extinguish fires at oil or gas wells most effectively, by interrupting the oil and/or gas flow from the well. As an example of further fields of use, the possibility to block a pipe can be mentioned, e.g. used for transport of hot water to radiators arranged within a specific area, e.g. an apartment, and thereafter to connect a flow depending metering means between a point before, respectively after, the point of interruption. It is thus possible to include various types of metering means in existing plumbing installations, e.g. for metering of hot water or heating comsumption, without interrupting the operation of the system. 
     The method according to the present invention is mainly characterized by the features disclosed in the following main claim, and the device for utilizing the method is mainly characterized by the features disclosed in the subclaims relating to the device according to the present invention. 
     In order to simplify the understanding the the invention, a number of embodiments for utilizing the method according to the present invention are described below by way of example, the embodiments being shown in connection with a first pipe, surrounded by a second pipe, intended to illustrate the type of tubular pipes generally used for transport of oil and/or gas from maritime wells, connected with an oil rig by means of double pipes, said first and surrounded pipe being the transport pipe for an oil and/or a gas flow. However, it should be emphasized, that the method and the device according to the invention can also be utilized in connection with a single pipe, without a surrounding second pipe. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows, partly in section, divided at a sectional line I--I in FIG. 2, a side view of a device according to the present invention arranged on a vertically extending pipe. 
     FIG. 2 shows a plan view of the device according to FIG. 1. 
     FIG. 3 is a cross-sectional view of the device disclosed in FIG. 2, said device being shown in a first and partially flow reducing position. 
     FIG. 4 is a fragment of the device shown in FIG. 3 in a corresponding cross-section, said device being arranged to totally interrupt the area of the inside pipe and thus also a media flow therethrough. 
     FIG. 5 is a principal cross-sectional view of a slightly modified embodiment of a device according to the present invention, arranged to partially interrupt a media flow through the inside and surrounded pipe. 
     FIG. 6 is a principal cross-sectional view corresponding to FIG. 5, the cross-sectional area of the inside pipe, and thus also the media flow, being totally interrupted. 
     FIG. 7 is a further principal cross-sectional view of a further modified embodiment, arranged to partially interrupt a media flow. 
     FIG. 8 is a cross-sectional view corresponding to FIG. 7, the device being arranged to completely interrupt the cross-sectional area of the pipe, and thus also the media flow through the pipe. 
     FIG. 9 is a longitudinal extending section of the embodiment as shown in FIG. 7. 
     FIG. 10 is a longitudinal extending section of the embodiment as shown in FIG. 8. 
     FIG. 11 is a partial cross-sectional view of a further modified embodiment of a device according to the present invention, shown immediately before the operation when a substantial reduction of the cross-sectional area of the pipe is achieved. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     With reference to the figures, reference numerals 1 and 2 indicate two housing parts, which can be joined to each other by means of a screw or a bolt connection or similar, thus arranged to sealingly embrace a pipe 3, which in the shown embodiment surrounds a second pipe 4. The second pipe 4 is a transport pipe for the media flow to be interrupted. In order to simplify the drawing figures of the device, the housing parts 1, 2 have been indicated with similar cross-sectional lines, and certain dividing lines are not shown. However, said dividing line is shown in FIGS. 1 and 2, showing flanges to be connected, and the dividing line extends through the housing 1, 2 along the dividing line for said flanges. The housing 1, 2, extends in direction from the pipe 3, 4, and includes two parallel and preferably cylindrical holes 5, 5&#39;, which serve as guiding cylinders for two piston means 6, 6&#39;, arranged movably in said holes or cylinders 5, 5&#39;. The distance between said holes 5, 5&#39; is so arranged, that the adjacent peripheral portions area arranged at a distance from each other smaller than the inside diameter of the inner pipe 4. The open portions of the holes 5, 5&#39; directed from the pipes 3, 4, are in the shown embodiments arranged closed by means of a lid 7, also being divided along the aforementioned dividing line. Between the piston means 6, 6&#39; and the lid 7, at least one explosive charge 8 is arranged, and an activating means 9 for said charge 8 is indicated extending through the lid 7. Said activating means 9 can obviously be of mechanical, electrical or any other previously known type, depending on the method of initiation for the charge that is desired. 
     In a basically perpendicular relationship to the holes 5, 5&#39; extending through the housing 1, 2 a tubular cylindrical part 10 extends from the pipes 3, 4, the length axis of said tubular part 10 being arranged corresponding to the center axis of the pipes 3, 4. Said tubular part 10 embraces and acts as a guide for a further piston means 11. A further explosive charge 12 is arranged between the end portion of said piston means 11 directed from the pipes 3, 4 and a lid 13, which seals the open end portion of the tubular part 10. Activating means 14 are also indicated at said lid 13, intended to facilitate initiation of the explosive charge 12. 
     With reference to the embodiment shown in FIGS. 1-4, FIGS. 1-2 show the device arranged embracing the outside pipe 3, the attachment being made by joining one housing part 1 and the tubular part 10 with the other housing part 2 by means of screws, bolts or similar. As shown in FIG. 2, all piston means 6, 6&#39;, 11 are arranged in a position adjacent to the respective lids 7, 13. The end portions of the two parallel piston means 6, 6&#39; directed towards the pipes 3, 4 are arranged to be concave, or in any other suitable manner, in order to improve the material removing action of the piston means 6, 6&#39; when contacting the pipes 3, 4. By influencing a first activating means 9, the explosive charge is initiated, or alternatively the explosive charges 8, which are arranged at the end portions of the piston means 6, 6&#39; directed from the pipes 3, 4. The piston means 6, 6&#39; are thus propelled with high speed in direction towards the pipes 3, 4, and when the front portion passes the pipes 3, 4, two opposed edge portions from the pipes 3, 4 are removed. The piston means 6, 6&#39; are further arranged with a through hole 15, 15&#39;, said holes being arranged with the center axis to basically coincide with the center axis of the piston means 11 arranged in the tubular part 10, when the first mentioned piston means 6, 6&#39; have completed their movement. 
     Thereafter, the second activating means 14 is influenced, and the explosive charge 12 arranged in the tubular part 10 is initiated, whereby the piston means 11 arranged in the tubular part 10 is brought to move with high speed in direction towards the pipes 3, 4, said piston means 6, 6&#39;, thus also through the pipes 3, 4, the through flow area thus being partially reduced, as shown in FIG. 3. According to this embodiment, the parallel piston means 6, 6&#39; are joined to each other at the portions directed from the pipe 3, 4, said joint partly acting as a means for maintaining the axis of the through holes 15, 15&#39; in the piston means 6, 6&#39; in a predetermined relationship to the axis of the perpendicular piston means 11, but also maintaining a simultaneous movement of the parallel piston means 6, 6&#39;. 
     With reference to FIG. 3, it is also shown that the crosswisely directed piston means 11 has a pointed part directed towards the pipes 3, 4, being followed by a cylindrical part, surrounded by a tubular means of a flexible and compressible material 16, said means 16 being arranged between the pointed part of the piston means 11 and a tubular member 17, in the embodiment joined to the piston means 11 by means of a screw thread. 
     When the piston means 6, 6&#39;, 11 have been brought to take up an internally, and also in relation to the tubular pipes 3, 4, locked position, the tubular member 10 can be removed, as shown in FIG. 4, whereafter the tubular member 17 by means of a tool can be rotated in relation to the crosswisely extending piston means 11, first moving the tubular member 17 in direction towards the pointed portion of the piston means 11. The elastic means 16 surrounding the piston means 11 is thus compressed, thereby completely closing the remaining cross-sectional area of the inside pipe 4, thus also completely interrupting the media flow through said tubular pipe 4. 
     When desired, it is also possible to completely regain original flow capacity through the inner tubular pipe 4. In this case, the crosswisely extending piston means 11 is removed by first bringing the elastic means 16 to the original shape, by unscrewing the tubular means 17 in direction from the forward and pointed portion of the piston means, whereafter the piston means 11 is completely removed, the parallel piston means 6, 6&#39; simultaneously being brought to take up an alternate angular position by a rotary movement, the holes 15, 15&#39; in the piston means 6, 6&#39; thus being prevented from communication with the inside pipe 4. The reduction in the cross-sectional area of the inside pipe 4 which is caused, is of such a small significance, that the reduction in flow capacity is negligible. 
     It should be emphasized, that the method also gives extremely good attachment properties against the tubular pipes 3, 4. When the parallel piston means 6, 6&#39; are initiated, an extremely good grip with the pipe 3, 4 is obtained, and when the crosswisely directed piston means 11 is activated, such attachment properties are obtained, that the device obviously will remain in position, regardless of existing flow speed and pressure. The device is also extremely suitable for use with pipes containing oil or gas, since there is no risk for fire when attached, in view of the fact that no oxygen is available. 
     The embodiment shown in FIGS. 1-4 is based on the use of an elastic compressible means 16 in connection with a threaded tubular member 17 in order to obtain total interruption in the inside tubular pipe 4. An alternative embodiment is shown in FIGS. 5-6, the piston means 11 being arranged with a portion having a smaller diameter, formed by means of two conical surfaces 18, also as previously using an elastic and compressible tubular means 16 as a sealing member. According to this embodiment, the tubular means 16 is arranged with stop means, which prevent the tubular means 16 from being moved past a predetermined position. During a continued movement of the piston means 11, the elastic tubular means 16 is pressed out in the inner tubular pipe 4, thereby achieving a total sealing action. 
     A further alternative embodiment is shown in FIGS. 7-10, the crosswisely extending piston means 11 being arranged with two sealing piston means 19, 19&#39;, the facing surfaces by means of a channel 20, arranged in the crosswisely extending piston means 11, arranged to communicate with a medium under pressure, such as a hydraulic or pneumatic medium. Alternatively, said channel 20 can be arranged to communicate with the area behind the end portion of the crosswisely extending piston 11 directed from the pipes 3, 4, the combustion gases in said area creating a pressure forcing the sealing piston means 19, 19&#39; to take up contact with the internal peripherial portion of the inside pipe 4. As can be easily understood, this embodiment also facilitates for a return movement, when desired, of the sealing piston means 19, 19&#39; to a position surrounded by the crosswisely extending piston 11, e.g. by connection of the channel 20 to a vacuum source. The sealing piston means 19, 19&#39; can also be returned by rotating the crosswisely extending piston 11, thereby first applying a pressure to one of the sealing piston means 19 from the medium in the pipe 4, whereafter a further rotary movement is carried out, approximately 180°, thereby also returning the second piston means 19&#39;. 
     The above described embodiments are used as examples of various methods to accomplish total interruption when the crosswisely extending piston 11 has completed its movement, but it is easily understood, that a number of possibilities exist for accomplishing said interruption, and further examples are therefore not regarded as necessary. 
     FIG. 11 indicates an alternative method to arrange the parallel piston means 6, 6&#39;, thereby completely removing the need for guidance and a corresponding movement. According to this embodiment, the parallel piston means 6, 6&#39; consist of relatively thin wall tubular members 21, 21&#39;, arranged with a relatively strong forward cutting wall 22, 22&#39;, arranged to remove two opposed wall portions of the tubular pipes 3, 4. Furthermore, a bottom part 23, 23&#39; is shown, arranged to act as a surface against which combustion gases from the explosive charges can act, even though said bottom portions 23, 23&#39; can be excluded in many cases. The crosswisely extending piston means 11 is arranged to penetrate the thin walls 21, 21&#39; when the charge 12 is initiated, which means that the holes 15, 15&#39; are completely eliminated and thereby also corresponding guiding means for the piston means 6, 6&#39;. This embodiment facilitates also in a simpler way rotation of the piston means 6, 6&#39;, if the original cross-sectional area of the pipe 4 should be reinstated, after removal of the piston means 11. 
     All of the embodiments described above with reference to the accompanying drawings concern devices intended for two pipes 3, 4, the inner pipe 4 being the pipe used for transport of a medium. This has been made with regard to the fact, that the method, and devices for utilizing the method, are extremely suitable for interrupting an oil or gas flow from a damaged pipe from a well under water, since the device can be attached by means of both automatic and manual devices, in view of the fact that the device consists of two mutually joinable parts. 
     Even though no embodiment with one pipe only has been shown, which is a simpler case, the device can obviously also be utilized for such pipes. This fact can easily be illustrated by considering the outside pipe 3 as the outside peripheral portion of a single pipe, the single pipe, and by this example, it is easily understood, that the method, as well as described embodiments for utilizing the method, without modification can also be used for this purpose. 
     Particularly in connection with single pipes only, means can be arranged which partly compress the wall portions between the parallel piston means 6, 6&#39; in direction towards each other, in which case said compression can be relatively small. This would make it possible for corresponding outside portions of the crosswisely extending piston means 11 to directly create complete sealing action and interruption of the media flow, preferably in connection with a smaller portion of the compressed tubular walls being formed, or removed, to a shape corresponding to the shape of the cross-wisely extending piston means 11. 
     The method according to the present invention is thus in no way restricted to the shown and described embodiments, since obviously a large number of modifications are possible within the scope of the inventive thought and the following claims.