WO2011143750A1

WO2011143750A1 - Apparatus and method for sealing a pipe

Info

Publication number: WO2011143750A1
Application number: PCT/CA2011/000576
Authority: WO
Inventors: Glenn Carson
Original assignee: Car-Ber Investments Inc.
Priority date: 2010-05-18
Filing date: 2011-05-18
Publication date: 2011-11-24

Abstract

An apparatus for sealing a pipe comprises a clamp assembly for frictionally engaging the pipe and a generally annular valve assembly for connecting to the clamp assembly and including a sealing means. A method is also provided wherein the clamp and valve assemblies are provided on a pipe and the pipe is cut at a position there-between. The valve assembly is then closed to seal the apparatus and, therefore, the end of the pipe.

Description

APPARATUS AND METHOD FOR SEALING A PIPE CROSS REFERENCE TO RELATED APPLICATIONS [0001] The present invention claims priority under the Paris Convention from US Patent Application No. 61/345,963, filed May 18, 2010, the entire disclosure of which is incorporated herein by reference. FIELD OF THE INVENTION [0002] The present invention relates to an apparatus and method for sealing a pipe. In one aspect, the invention relates to an apparatus and method for severing a portion of a pipe and sealing the end of the remaining portion. BACKGROUND OF THE INVENTION [0003] Liquid or fluid materials are normally transferred using equipment such as conduits or pipes. Pipes are also used in oil and gas drilling operations. In some instances, it becomes necessary to seal a pipe in order to prevent leakage. One example of such an instance involves the recent catastrophe experienced with the Deepwater Horizon drilling rig. In such case, the drilling rig was severely damaged after an explosion during the drilling operation and the pipe extending from the rig into the subsea hydrocarbon (i.e. oil and gas) reservoir was severed. In the result, a vast amount of oil from the reservoir has been spilled into the Gulf of Mexico through the severed pipe. Various solutions to seal or cap the pipe have been proposed and attempted without success. Although the event surrounding the Deepwater Horizon is one example of a situation where emergency sealing of a pipe is needed, it will be understood that various other similar situations will arise where a pipe requires sealing. This will include pipes that are submerged or on land and conveying any type of fluid (i.e. liquid or gas). Such pipes may or may not be leaking the fluid. Another problem is faced in a case such as the Deepwater Horizon wherein the severed pipe is jagged or otherwise deformed, thereby making it difficult to seal the end of such pipe. [0004] There exists therefore a need for efficiently closing and sealing a pipe. SUMMARY OF THE INVENTION [0005] In one aspect, the present invention generally provides an apparatus for sealing an open end of a pipe comprising: a clamp assembly and a valve assembly; wherein: [0006] - the clamp assembly is adapted to frictionally engage the outer surface of the pipe and to prevent relative movement between the pipe and the clamp assembly;

[0007] - the valve assembly including a valve means;

[0008] - the valve assembly and clamp assembly being adapted to sealingly engage each other to form a sealed space there-between by closing the valve means;

[0009] - the sealed space enclosing an open end of the pipe.

[0010] In another aspect, the invention provides a method for closing an end of a pipe.

[0011] In another aspect, the invention provides a method and apparatus wherein a deformed portion of a pipe may be cut off, thereby leaving a "clean" end for forming a seal.

[0012] Thus, in one aspect, the invention provides an apparatus for sealing an end of a pipe, the apparatus comprising:

[0013] - a clamp assembly for frictionally engaging the outer surface of the pipe;

[0014] - a valve assembly for closing and sealing an end of the pipe;

[0015] - a means for urging the valve assembly towards the clamp assembly;

[0016] - a first sealing means for forming a seal between the clamp assembly and the valve assembly.

[0017] In another aspect, the invention provides a method of sealing an end of a pipe comprising.

[0018] - providing a damp assembly on the pipe and frictionally and sealingly engaging the clamp assembly on the pipe;

[0019] - providing a generally annular valve assembly on the pipe;

[0020] - sliding the valve assembly towards clamp assembly;

[0021] - cutting the pipe at a location between the clamp and valve assemblies;

[0022] - urging the valve assembly against the clamp assembly to form a seal there- between;

[0023] - sealing the valve assembly. BRIEF DESCRIPTION OF THE DRAWINGS [0024] These and other features of the invention will become more apparent in the following detailed description in which reference is made to the appended drawings wherein; [0025] Figure 1 is a cross sectional view of a pipe to be sealed. [0026] Figure 2 is a cross sectional view of the clamp assembly of the invention being positioned over the pipe. [0027] Figure 3 is a cross sectional view of the clamp assembly in the assembled state and the valve assembly being positioned over the pipe. [0028] Figure 4 is a cross sectional view of clamp and valve assemblies in the assembled state and wherein the valve assembly is being connected to the clamp assembly. [0029] Figure 5 is a cross sectional view of the clamp and valve assemblies in the connected position with the valve means open. [0030] Figure 6 is a cross sectional view of the assemblies in the connected position with the valve means closed. [0031] Figure 7 is a bottom perspective view of a clamp assembly according to another aspect of the invention in a fully open position. [0032] Figure 8 is a top perspective view of the clamp assembly of Figure 7 in a partially closed position. [0033] Figure 9 is a perspective detail of a locking arm according to an embodiment of the clamp assembly of Figure 7. [0034] Figure 10 is a top view of the clamp assembly of Figure 7. DETAILED DESCRIPTION OF THE INVENTION [0035] In the present description of the invention, the term "axial" will be used to describe a direction taken along the longitudinal axis of a pipe or conduit. Thus, "axial force" or "axial stress" will be understood as being a force applied in a direction generally parallel to the longitudinal axis of the conduit. Similarly, the term "axially extending" will be understood to mean extending in a direction parallel to the longitudinal axis of the pipe. [0036] Figure 1 illustrates a pipe 10 requiring sealing. In the view shown in Figure 1 , the pipe 10 lies on a seabed 12. As will be understood, such an orientation of the pipe 10 is only for illustration and the pipe may be in any type of orientation, such as vertical or any angled position. Further, as discussed above, the present invention will be described with reference to a pipe provided underwater. However, it will be understood that the invention will be applicable to a pipe in any environment, such as underwater or on land. As will be understood by persons skilled in the art, the invention is particularly suited for use in subsea conditions. [0037] Figure 2 illustrates an optional preparation stage according to one aspect of the method of the invention, wherein the seabed in a region of the pipe 10 is excavated so as to expose the circumference of a pipe section. The section of the pipe comprises either an open end or, as shown in the attached figures, a section to be cut so as to form an open end. It will be understood that such excavation will only be required in cases where the pipe 10 is lying on a surface, such as a seabed or the ground (for land-based situations). In cases where the pipe, or the pipe section in question, is raised above the surface, or is vertical or angled with respect thereto, it will be understood that the need for any excavation will be avoided. [0038] Figure 2 also illustrates the first stage or step of the method of the invention, wherein a clamp, such as a generally circumferential clamp assembly 20 is provided over a section of the pipe 10. As described below, the clamp assembly 20 is adapted to frictionally engage the outer surface of the pipe 10 with sufficient strength so as to prevent relative axial movement between the clamp assembly 20 and the pipe 10. In one aspect of the invention, the clamp assembly 20 is formed of two or more sections that are provided over the pipe. In the embodiment shown in Figure 2, the clamp assembly 20 is formed of two sections 22a and 22b. It will be understood by persons skilled in the art that a large diameter pipe may require more than two clamp sections in order to reduce the weight of the section and permit ease of handling by the maintenance personnel. The sections of the clamp assembly 20 (i.e. sections 22a and 22b) are designed so as to be joined together over the outer circumference of the pipe 10. In the case of a two section clamp as shown in Figure 2, each section 22a and 22b will preferably have a curved inner surface that generally corresponds to the curvature of the pipe. In order to allow a given clamp to be used with a variety of pipe sizes (i.e. diameters), it will be appreciated, in view of the present description, that the curvatures of the clamp sections do not need to exactly correspond to the shape of the pipe. [0039] According to one aspect of the invention, each of the sections 22a, 22b includes a flange portion shown as 24a and 24b, respectively (which combine to form a flange portion 24), and a clamp portion shown as 26a and 26b, respectively (which combine to form a clamp portion 26). The clamp portions 26a and 26b are adapted to engage the outer circumference of the pipe 10, when the the portions are joined together. The clamp sections are preferably elongated so as to engage a given or pre-determined length of the pipe 10. As mentioned above, the clamp assembly 20 is adapted to frictionally engage the surface of the pipe 10. Thus, as will be understood, a longer clamp portion 26 increases the contact surface area with the pipe and, thereby, increases the frictional engagement force there- between. [0040] According to one aspect of the invention, each of the clamp portions 26a, 26b includes a preferably curved, pipe engaging sections 28a and 28b, respectively (which combine to form pipe engaging section 28), adapted to conform at least partially to the outer surface of the pipe 10. According to a preferred aspect of the invention, the clamp portions 26 further include a means for connecting one portion to the other. In one embodiment, such means for connecting comprises radially outwardly extending flanges or plates shown as 30a and 30b, respectively, preferably provided on opposite ends of the pipe engaging sections 28a, 28b, and which extend axially along at least a portion of the length of the sections 28a, 28 b. The plates 30a and 30b of each clamp portion 26 are adapted to cooperate with each other. Specifically, as shown in Figure 2 and 3, once the clamp assembly 20 is positioned over the pipe 10, the plates 30a, 30b of opposed clamp portions 26a, 26b face each other. Although the figures show the apparatus from one side, it will be understood that a mirror image of the apparatus will be observed from the opposite side. [0041] As shown in Figure 2, each of the plates 30a, 30b, are preferably provided with a plurality of bolts 32 extending towards the cooperating plates of the opposite clamp section. The plates 30a, 30b also include boltholes 34 for receiving the bolts 32 of the opposed plate. It will be noted in Figure 2 that, according to one aspect of the invention, the bolts 32 and boltholes 34 of each plate 30a, 30b are provided in an alternating manner. As will be understood, such an arrangement is a preferred embodiment of the invention and that other arrangements are possible. For example, in one embodiment, all of the required bolts 32 may be provided on one of the plates 30a or 30b. Alternatively, the bolts 32 may be provided on one end of the plate while boltholes are provided on the opposite end of the plate. The number of bolts 32 (and, correspondingly, the number of boltholes 34) may vary based on the length of the plates 30a, 30b. The bolts 32 shown in Figure 2, and those shown in other figures, are illustrated as being integral with the plates 30a, 30b or other portions of the apparatus. It will be understood that this is a preferred embodiment. In other embodiments, the bolts shown herein can be separate elements that are inserted through boltholes. For underwater applications, it will be understood that having integral bolts offers an advantage during the assembly steps since the number of loose elements are reduced. [0042] In the above description, it is indicated that nuts are used in association with the bolts 32, However, as shown in the figures, the apparatus may preferably be further provided with tensioners 35 in order to ensure that the respective assembly is maintained in a tightened manner. The tensioners 35 are preferably hydraulic tensioners, which are commonly known in the art. In a specific embodiment, wherein the apparatus of the invention is used in underwater applications, the tensioners comprise subsea tensioners, such as those manufactured by Hydratight Operations Limited under the name Aqua-Jack™. [0043] In the preferred embodiment of the invention, the clamp assembly 20 further includes a circumferential sealing means such as seal 36, which may comprise a gasket or the like. The seal 36 is preferably provided in the same number of sections as the clamp sections 22 Thus, for the embodiment shown in Figure 2, the seal 36 is provided in two sections 36a and 36b, each of which is provided in association with the clamp sections 22a and 22b. In operation, the seal 36 selves to form a pressure seal between the clamp assembly 20 and the pipe surface once the clamp assembly 20 is assembled (as shown in Figure 3), [0044] In a further embodiment of the invention, it will be understood that the clamp assembly 20 may comprise two sections as shown in Figure 2 but connected by a hinge along one side. [0045] Figure 3 illustrates the clamp assembly 20 in an assembled state over the surface of the pipe 10. As shown, once assembled, the bolts 32 of one clamp portion are inserted through the boltholes 34 of the opposed clamp portion. Nuts (not shown) are then supplied on the bolts 32 and tightened so as to force a frictional engagement between the clamp assembly 20 and the pipe 10. As discussed above and as shown in Figure 3, once the clamp assembly 20 is assembled, the circumferential seal 36 engages the pipe 10. In a preferred embodiment of the invention, the clamp assembly 20 is provided with an internal diameter that is slightly smaller than the outer diameter of the pipe 10. In this manner, once the clamp assembly 20 is secured to the pipe 10 and the nuts associated with the bolts 32 tightened, the frictional engagement between the clamp assembly 20 and the pipe 10 is enhanced. It will be understood that in such arrangement, the seal provided by the circumferential seal 36 is also enhanced. [0046] Figure 3 also illustrates the next stage of the method of the invention. At this point, once the clamp assembly 20 is secured to the pipe 10, a valve assembly 50 is then positioned over the pipe 10. The valve assembly 50 comprises a generally annular body, having an inner diameter that is sized to receive the pipe 10. In one aspect of the invention, the valve assembly 50, which in one embodiment comprises two or more sections in the same manner as the clamp assembly 20 discussed above. Thus, in the embodiment shown in the Figures, the valve assembly comprises two sections 52a and 52b. Each of the valve assembly sections 52a and 52b includes opposing plates 54a and 54b, which provide one example of a means for joining the sections 52a and 52b together. As shown in Figure 3, one of the plates such as 54b may be provided with bolts 56 extending in the direction of the other of the plates 54a, when in the assembled state. The opposed plates 54a, 54b are adapted to be joined to each other. For example, the opposing plate, 54a, may be provided with boltholes 58 for receiving the bolts 56, as shown in Figure 4. Nuts (not shown) are then provided on the bolts 56 and tightened. It will be understood that, as described above, the number and orientation of the bolts 56 may vary as needed. As shown in the figures, tensioners such as those discussed above are preferably used with the nuts provided on the bolts 56. [0047] As shown in Figure 3, one or both of the plates 54a and 54b may be provided with a sealing means comprising a seal or gasket 60, for forming a seal between the sections 52a and 52b forming the valve assembly 50, when the plates 54a and 54b are combined [0048] The sections 52a and 52b of the valve assembly 50 are further provided with a means for connecting same with the clamp assembly 20. In one aspect, such connection is achieved using bolts 62 extending from the respective section 52a and 52b towards the flange portion 24 (formed by sections 24a and 24b) of the clamp assembly 20, which are provided with boltholes 38 to receive the bolts 62. [0049] The valve assembly 50, once formed, includes a slot 66 for receiving a valve means to close off the opening of the annular assembly 50 (as discussed further below) and, therefore, resulting in a sealing of end of the pipe 10. The valve means may comprise, for example, a gate 68 that is received slidably therein. The purpose of the gate will be made clear below. Although the present description will recite a "gate" as forming the valve means, various other types of valves will be understood as being equally applicable for achieving the purpose of closing an opening. However, for the specific purpose outlined herein by example (i.e. undersea application), a gate or gate valve, will be understood as being efficient for use. [0050] The sections 52a and 52b of the valve assembly 50 are sized so as to allow the assembly 50 to be slidably provided over the pipe 10 once such sections are assembled. Although the valve assembly 50 is described herein as being formed of sections, in another embodiment it would be understood that the assembly may comprise a unitary structure or a two-piece structure that is connected by a hinge. In the case of a unitary structure, it will be understood that that assembly would be slid onto the end of the pipe 10 and moved there- over to the desired location. In such case, the unitary assembly would have a general shape of a ring and may not require the piate portions 54a, 54b. [0051] Figure 4 illustrates the next stage of the method of the invention. Specifically, once the valve assembly 50 is assembled over the pipe 10 (or slid onto the pipe as in the case of a unitary structure), it is slid axially over the pipe towards the clamp assembly 20, which has been previously anchored on the pipe. It will be understood that the assembly of the assembly 50 over the pipe is a preferred embodiment, in cases where the pipe lies under water. It may be possible, for example, for an assembled assembly to be provided over the end of the pipe 10 in the same manner as would be done with an assembly having a unitary structure. Once the assembly is positioned where desired along the length of the pipe 10, the bolts 62 provided on the valve assembly 50 are inserted into the boltholes 38 provided on the flange portion 24 of the clamp assembly 20. Nuts (not shown) are then secured to the bolts thereby forcing the valve assembly 50 towards the clamp assembly 20. As discussed above, such nuts are preferably also preferably provided with tensioners as illustrated in the figures. One or both of the opposing faces of the two assemblies is preferably provided with a seal or gasket 64. [0052] In one embodiment of the invention, prior to fully advancing the valve assembly 50 against the clamp assembly 20, the portion of the pipe 10 located between the two assemblies is cut. This may be achieved using any variety of means. For example, a rotating blade may be used to cut the circumference of the pipe. Alternatively, an electrode, such as that shown at 70, may be used to melt a discrete section of the pipe and thereby allowing separation of the pipe into two sections at such region of melting. Other means of cutting the pipe will be known to persons skilled in the art. [0053] Figure 5 illustrates the next step of the method, wherein the pipe 10 has been cut as described above and the unnecessary section of the pipe, identified at 13, is removed. To facilitate the removal process, any type of clamp or rig, 72, may be used. Once the unnecessary pipe section 13 is removed, the valve assembly 50 is urged against the clamp assembly by tightening of the nuts associated with the bolts 62. Such tightening is continued until a tight seal is formed between the two assemblies, as a result of the seal 64. [0054] Figure 6 illustrates the following step in the method, wherein the valve means is closed. In the embodiment illustrated, this is achieved when the gate 68 is inserted into the slot 66 provided in the valve assembly so as to form a sealed space 74, bounded by the clamp assembly and the valve assembly, the latter of which includes the gate 68. It will be understood that to form a comprehensive seal, the slot 66 may be provided with a seal or gasket to engage the gate 68 to further seal the space 74. [0055] As will be understood, once the step illustrated in Figure 6 is completed, the open end of the pipe 10, formed after the cutting step shown in Figure 4, the apparatus of the invention serves as a cap or seal, thereby preventing any further liquid from the pipe 10 from escaping. [0056] The above description includes a step of cutting a portion of the pipe being sealed. As will be understood, this step is preferred, particularly in cases where the open end of the pipe in question is ruptured or otherwise damaged, thereby preventing closing the pipe in another manner. Thus, the method of the invention includes the step of forming a "clean'' opening that can be more effectively sealed. It will, however, be appreciated that in cases where the pipe does include a clean opening, the apparatus and method of the invention may equally be used with the omission of the cutting step. [0057] As discussed above and as shown in the figures, the clamp assembly includes a flange portion formed by portions 24a and 24b. As shown in the figures, the valve assembly has a similar flange portion. As described above, each of the opposed flange portions of the two assemblies combine to form a sealed enclosure, which comprises the sealed space 74. It will be appreciated that the dimensions of the flange portions are not limited. For example, according to the aspect of the invention shown in the figures, such flange portions may have some extended portions, which face each other when the assemblies are combined to form the apparatus of the invention. Such extended portions may be of any length and may be the same or equal on each of the assemblies. In this way, the volume of the sealed space 74 may be varied. In another aspect, the extended portions may not exist on one or both of the assemblies. Where no extended portions are provided, it will be understood that the volume of the sealed space 74 would be negligible. However, it will be understood that in the preferred embodiment, some volume for the space 74 should be provided and, therefore, one or both of the subassemblies will preferably include some amount of the extended portions. [0058] Figures 7 to 10 illustrate a further embodiment of the clamp assembly of the invention. As shown, the clamp assembly 100 comprises a pair of generally "U" or horseshoe shaped plates 102, 104 that are arranged in a generally parallel and spaced apart manner. The plates 102, 104 are designed to receive a pipe therein. Thus, the plates may be lowered onto a pipe lying on a base, such as a seabed, or otherwise provided on any orientation of a pipe, as will be understood by persons skilled in the art. The assembly 100 also includes a cover 106 that is adapted to cover a portion of the pipe received within the opening of the "U" shaped plates 102, 104. The assembly 100 also includes a pair of boxes 108, 110 connected to opposite sides of the plates 102, 104. [0059] The clamp assembly 100 also includes one or more pairs of opposed clamping arms. In the embodiment shown in Figures 7 to 10, the assembly 100 includes two pairs of arms, 112a, 112b and 114a, 114b. Each of the arms 112a, 12b, 114a and 114b are connected to the rams of respective hydraulic cylinders 116. As shown, the cylinders are supported within the boxes 108, 110, The cylinders 116 serve to advance the pairs of arms towards each other and towards the opening the "LT shaped plates. As will be understood, when the assembly 100 is provided on a pipe, activation of the cylinders 116 serves to force the ends of the arms against the outer wall of the pipe. Each of the clamping arms is provided with an curved portion that is adapted to receive the side of the pipe adjacent the opening of the "U" shaped plates 102, 104. This is illustrated, for example, in Figure 8, which shows the arms 114a and 114b when brought towards each other. The curved portions of the arms are preferably provided, in one aspect of the invention, with a sealing means, or seal 115, which serve to grip the pipe when the opposed pairs of arms are brought together. In a further embodiment, sections of the cover 106 corresponding and opposite to the positions of the seals 1 15 are provided with corresponding seals 117. As will be understood, in such manner, the seals 115 and 117 serve to frictionally grip the outer wall of a pipe once the assembly 100 is engaged thereon. [0060] As also shown in Figure 8, the opposed ends of the clamping arms 114a and 1 14b are provided with cooperative jaws that are designed to engage each other. In one aspect, the opposed jaws may be angled so as to cause the opposed pair of arms 114a and 114b to move in a directly towards the closed of the "U" shaped plates 102, 104. In this way, the arms 1 14a, 114b are urged further against the wall of the pipe so as to further increase the gripping force on the pipe wall. [0061] In another aspect, the assembly 100 may include a pair of planar seals 118a, 118b provided on opposite sides of the plates 102, 104. The seals 118a, 118b are preferably secured to the plates 102, 104 by gluing or other such attachment means as may be known in the art. The seals 118a, 118b are designed to be deformed as the arms are moved towards each other so that the seals 118a, 118b are wrapped around the pipe. In this way, a further seal or frictional grip is provided between the pipe and the clamp assembly 100. [0062] In the above description of the clamp assembly 100, reference is made to two pairs of opposed clamping arms. However, it will be understood that any number of pairs of such arms can be used including one pair, two pairs, three pairs etc. It will be understood that increasing the number of opposed arm pairs increases the amount of frictional grip between the pipe and the assembly 100. [0063] In another preferred embodiment, the assembly 100 includes one or more locking arm 120 having a toothed end 122. The locking arm 120 is adapted to extend to the opposite side of the assembly and latch on to a cooperating member so as to form a positive engagement there-between. The locking arm 120 is connected to the same hydraulic ram as one of the clamping arms, such as 112a, whereby the final closed, or clamped position of the clamping arm is locked. [0064] As illustrated in Figures 7 to 10, the plates 102, 104 of the clamp assembly 100 may be provided with a plurality of boltholes for receiving a valve assembly 50 as described above. In other words, a valve assembly 50 may be connected to the clamp assembly 100 in the same manner as shown in Figure 3 to 6. Thus, as will be understood, the clamp assembly 100 allows the same clamping effect to be achieved on a pipe without the need to excavate under the pipe or, alternatively, requiring minimal excavation. [0065] It will also be appreciated that the apparatus of the invention may be subject to various modifications to accommodate for different pipe sizes etc. In another aspect, the clamp assembly of the invention may be substituted with a clamp as taught in applicant's co- pending application number 12/715,168, the entire contents of which are incorporated herein by reference. [0066] The clamp assembly of the present invention is capable of remaining secured to the pipe even when subjected to very high pressures.

[0067] Although the invention has been described with reference to certain specific embodiments, various modifications thereof will be apparent to those skilled in the art without departing from the purpose and scope of the invention as described herein. Any examples provided herein are included solely for the purpose of illustrating the invention and are not intended to limit the invention in any way. The drawings provided herein are solely for the purpose of illustrating various aspects of the invention and are not intended to be drawn to scale or to limit the invention in any way.

Claims

WE CLAIM:

1. An apparatus for sealing an end of a pipe, the apparatus comprising:

- a clamp assembly for frictionally engaging the outer surface of the pipe;

- a valve assembly for closing and sealing an end of the pipe;

- a means for urging the valve assembly towards the clamp assembly;

- a first sealing means for forming a seal between the clamp assembly and the valve assembly.

2. The apparatus of claim 1 , further comprising a second sealing means for forming a seal between the clamp assembly and the pipe.

3. The apparatus of claim 1 , wherein the clamp assembly comprises two or more sections that are connectable together and which combine to circumferentially surround the pipe.

4. The apparatus of claim 3, wherein the clamp assembly sections are connected by mechanical means.

5. The apparatus of claim 4, wherein the clamp assembly sections include axially generally extending flanges and wherein a connecting means connects opposed pairs of flanges.

6. The apparatus of claim 3, wherein the clamp assembly sections include a hinged connection.

7. The apparatus of claim 1 , wherein the valve assembly generally comprises an annular body having an inner diameter adapted to receive the outer diameter of the pipe.

8. The apparatus of claim 7, wherein the valve assembly comprises two or more sections that are connectable together.

9. The apparatus of claim 8, further comprising a seal between each pair of valve assembly sections.

10. The apparatus of claim 7, wherein the valve assembly includes a valve means for closing the inner diameter thereof.

11. The apparatus of claim 10, wherein the valve means comprises a gate.

12. The apparatus of claim 11 , wherein the valve assembly includes a seal for the gate.

13. The apparatus of any one of claims 1 to 12, wherein at least one of the clamp assembly and valve assembly includes an extended flange portion, wherein the extended flange portion extends between the clamp assembly and valve assembly,

14. The apparatus of claim 13, wherein the clamp and valve assemblies combine to form a sealed space there-between.

15. The apparatus of any one of claims 1 to 14, wherein the apparatus further includes a means for cutting the pipe at a location between the clamp and valve assemblies.

16 The apparatus of claim 1, wherein the clamp assembly comprises a generally "U" shaped body adapted to receive a section of the pipe therein, the assembly comprising;

- a pair of generally parallel and spaced apart plates, the plates having a general "U" shaped structure;

- at least one pair of opposed clamping arms, provided on opposite sides of the body;

- the opposed clamping arms being connected to an urging means for moving the clamping arms towards each othe;

- the clamping arms being adapted to engage and grip the wall of the pipe.

17. The apparatus of claim 16, wherein the first sealing means comprises a seal member provided on the at least one pair of opposed clamping arms.

18. The apparatus of claim 17, wherein the at least one pair of clamping arms comprise curved end portions for engaging the pipe.

19. The apparatus of claim 16, further comprising a locking means for locking the clamp assembly once engaged on a pipe.

20. The apparatus of claim 16, wherein at least one of the plates is adapted to be connected to the valve assembly.

21. A method of sealing an end of a pipe comprising:

- providing a clamp assembly on the pipe and frictionally and sealingly engaging the clamp assembly on the pipe;

- providing a generally annular valve assembly on the pipe;

- sliding the valve assembly towards clamp assembly;

- cutting the pipe at a location between the clamp and valve assemblies;

- urging the valve assembly against the clamp assembly to form a seal therebetween;

- sealing the valve assembly.

22. The method of claim 21 , wherein the clamp assembly comprises two or more sections and wherein the step of providing a clamp assembly on the pipe comprises joining the two or more clamp assembly sections together.

23. The method of claim 21 , wherein the valve assembly comprises two or more sections and wherein the step of providing a valve assembly on the pipe comprises joining the two or more valve assembly sections together.

24. The method of claim 21 , wherein the step of cutting the pipe comprises mechanically cutting the pipe.

25. The method of claim 21 , wherein the step of cutting the pipe comprises electrically heating the pipe.