NZ564634A - Temporary pipe brace - Google Patents

Abstract

A temporary pipe joint brace 20 includes an engagement section 23 for engaging with a pipe joint section 24, 25, 26 and a clamping section 28 for clamping a first pipe 22 slidably engaged with the joint section to prevent sliding of the first pipe relative to the joint section. The brace includes degradable components such as the fasteners 27 joining the split halves of the brace about the joint, which when degraded after some time in the laid pipe environment release the pipe brace to allow movement of the first pipe relative to the pipe joint on the second pipe 21.

Description

OurRef: IPN107 Patents Form No. 5 PATENTS ACT 1953 Complete After Provisional No. 564634 Filed 19 December 2007 COMPLETE SPECIFICATION PIPE BRACE We, Iplex Pipelines NZ Limited, a New Zealand company of 67 Maiden Street, Palmerston North, New Zealand do hereby declare the invention for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: 564634 A Pipe Brace Field of the Invention The invention relates to a pipe brace.

Background Pipes are widely used for supply of water and gas and for the removal of waste. However, pipes are generally rigid or with only limited flex. Limited flex may allow a pipeline to adjust to small variations in the pipeline path caused, for example, 10 by movements in the ground carrying the pipe. Generally also, joints in pipes are points of weakness, with seals employed at such points prone to failure.

During earthquakes, or significant ground subsidence, significant changes in the path followed by the pipe can occur. This is particularly problematic because 15 such changes can result not only in lateral changes to the path but also in changes to the length of the path. Any changes in length generally result in failure of rigid pipelines and even of pipelines with limited flex because the length of the pipeline is fixed.

Although some solutions offering variable length have been suggested, these are generally overly complex and therefore expensive to implement, requiring specialised parts. The parts used, although variable in length, may be prone to failure for other reasons such as weakness of the materials used or the complexity of the joint.

Trenchless pipe laying technology is increasingly becoming the installation method of choice - at least in circumstances where it is an available option. This is particularly so in non-pressure sewer and stormwater applications, and in the underground installation of cable duct. The key advantage being the avoidance 30 of disruption to above ground activities and facilities.

However, trenchless pipe laying generally involves pushing or pulling a pipe through the ground, often through a pre-drilled bore. Such techniques are not suitable for variable length pipes because they tend either to compress or to 35 lengthen the pipe. This can pull the pipe apart, or damage the joint or simply 2 564634 result in a pipe which is fully compressed or lengthened and therefore does not alter its length when required to do so. Therefore the most practical known method of installing variable length pipes is by trenching.

Another area of difficulty is in situations where a degree of axial restraint is required, such as exists in proximity to a valve or a bend where hydraulic thrust forces can be expected. Typically in such situations thrust blocks must be installed, requiring installation by conventional open trenching rather than by trenchless methods such as directional drilling.

Both of the aforesaid areas of difficulty are exacerbated in installations on steep grades, where conventional rubber ring joints may pull apart.

It is an object of the invention to provide a pipe brace which facilitates installation 15 of pipelines, or which at least provides the public with a useful choice.

Summary of the Invention In a first broad aspect the invention provides a pipe brace configured to prevent movement of a first pipe relative to a pipe joint or a second pipe during pipe 20 installation wherein the brace is configured to fit to a first pipe and a joint section of a second pipe , the first pipe being slidably engaged with the joint section of the second pipe, the brace including an engagement section for engaging with the joint section and a clamping section for clamping to the first pipe to prevent sliding movement of the first pipe relative to the joint section.

Preferably the engagement section is engagable with a protrusion on the joint section of the second pipe.

Preferably the joint section includes an internal groove for receiving a seal, the 30 internal groove forming an external protrusion, and the engagement section is configured to engage with a said external protrusion on the joint section of the second pipe.

Alternatively, the brace may include two clamping sections, one for clamping to 35 each pipe. 3 564634 Preferably the pipe brace is formed in two halves which together wrap around the circumference of the first pipe and the joint section of the second pipe.

Preferably the pipe brace includes one or more fasteners which, in use, join the two halves.

Optionally the pipe brace includes one or more degradabie components, wherein degradation of the degradabie components results in release of the pipe brace to 10 allow movement of the first pipe relative to the pipe joint on the second pipe.

In this specification, the term "degradabie" means capable of breaking down in any suitable manner, including by: rusting, oxidation, corrosion, dissolution, biodegradation, softening due to contact with ground water, reactions with ground 15 water or chemicals in the ground, reactions with chemicals applied to the component before or during installation, reactions between parts of the component or between different components of the pipe brace, or any other suitable means of causing failure of the component.

Degradabie components include those where only a part of the component degrades.

Preferably the fasteners joining the two halves are degradabie.

Preferably the fasteners are positioned in or near a clamping section, so as to tighten the clamping section around a pipe and to release the clamping section when the fasteners degrade.

Preferably the degradabie components are configured to fail in less than 12 30 months, more preferably less than 3 months.

Preferably the temporary pipe brace is shaped to reduce resistance to pushing or pulling of the pipe during installation. Preferably the pipe brace is tapered at one or both ends. 4 564634 The use of a temporary brace gives rigidity around the joint, allowing installation by pushing or pulling the pipe, possibly through a preformed bore, without the need to dig a trench. After installation the brace releases, allowing the benefits of a sliding joint to be realised.

A sliding joint allows the length of a pipe to adjust through alteration of the position of the pipe within the joint section. The pipe joint is therefore suited for applications in earthquake zones or where ground subsidence can be expected.

In some such situations digging a trench may be undesirable, dangerous or impractical. The invention allows installation of pipes including sliding joints in these situations without trenching.

Brief Description of the Drawings The invention will now be described by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a first cross-sectional view of an expandable pipe joint; Figure 2 is a similar view to Figure 1, illustrating the slidable nature of the expandable pipe joint; Figure 3 is a cross-sectional view of a pipe brace according to a first embodiment of the invention positioned on a pipe joint of the type 25 illustrated in figure 1; Figure 4 is a perspective view of part of the pipe brace of Figure 3; Figure 5 is a cross-sectional view of another embodiment of a pipe brace 30 according to the present invention for bracing two pipes around a join; and Figures 6a to 6d are a series of schematic side elevations showing trenchless installation of a pipeline. 564634 Detailed Description of the Preferred Embodiments Figure 1 is a cross-section along the length of a pipe joint 1. The pipe joint 1 joins a first pipe 2 and a second pipe 3, and includes a joint section 4 which has an internal diameter D-, greater than the external diameter D2of the pipes 2, 3 to 5 be joined.

In the pipe joint illustrated the joint section 4 is a sleeve which fits over the outside of the pipes to be joined. The joint section 4 includes a number of radial grooves or recesses 5 for receiving annular seals 6 for sealing the pipe joint 1. 10 The grooves or recesses 5 may be formed simply by deformation of the wall of the joint section 4. Alternatively, grooves or recesses 5 could be machined in any suitable manner.

The seals 6 effectively seal the ends of the joint section 4 against the outside 15 walls of the pipes 2, 3 to be joined.

The seals provide a sliding connection, such that the pipes 2, 3 can slide with respect to the joint section 4. Figure 2 shows the pipe joint 1 with the pipes 2, 3 having slid outwards from the position shown in Figure 1.

The pipes 2, 3 can be installed at an intermediate position so as to allow for both contraction and expansion of the pipe length.

The length of the joint section 4 also allows for good alignment of the pipes 2, 3. 25 Alignment is desirable because circular profile seals generally work best when positioned between aligned pipes. Misalignment presents an elliptical rather than a circular pipe cross section to the seal.

The pipes 2, 3 and the joint section 4 may be formed from any suitable material. 30 The invention is particularly suited to use with PVC piping. The joint section 4 may be formed from MPVC (modified polyvinyl chloride) or UPVC (unplasticised polyvinyl chloride). The pipes 2, 3 may be formed from OPVC (oriented polyvinyl chloride). 6 564634 This pipe joint is particularly suited to applications in earthquake zones or where ground subsidence is to be expected. The variable length of a pipeline containing the pipe joint allows the pipeline to alter length to compensate for alterations in the pipeline path caused by shifting ground.

Figure 3 shows a pipe brace 20 according to a preferred embodiment of the present invention installed on a joint section 21 and pipe 22. Similar pipe braces 20 may be applied to any type of sliding connection between two pipes or between a single pipe and a pipe joint section.

The pipe brace 20 includes an engagement section 23 which engages with the protrusion 24 formed by creation of the radial groove or recess 25. The groove or recess 25 receives an annular seal 26. As the pipe brace is intended to prevent sliding movement, its engagement with the protrusion 24 provides a positive 15 engagement with the joint section 21.

The pipe brace is formed from a pair of pipe brace halves (only one of which is shown in Figure 3) which together wrap around the pipe and pipe section. The two brace halves are joined using fasteners passing through a pair of holes 27.

The pipe brace 20 also includes a clamping section 28, which engages with the pipe 22. The holes 27 are situated in or near the clamping section 28, such that tightening of fasteners passing through those holes will force the two brace halves together particularly in the region of the clamping arrangement. An inside 25 surface 30 of the clamping section then pinches against the pipe 22. The adjacent portions 31 of this inside surface are recessed slightly, to allow a strong friction engagement between the surface 30 and the pipe 22.

Thus, although the pipe 22 is mounted to the joint section 21 in a sliding join, the 30 pipe brace 20 prevents relative movement of the pipe 22 and joint section 21.

Figure 4 is a perspective view of half of a pipe brace according to the present invention similar to that shown in Figure 3. This drawing shows more clearly the construction of the brace in two parts, each identical to that shown in Figure 4. 35 The parts are joined by a pair of bolts passing through holes 27. However, any 7 564634 other suitable fastening arrangement could be used. For example, the two parts of the brace could be hinged and joined at an opposite edge by a single bolt.

Optionally after installation the pipe brace 20 can be configured to release, such 5 that the pipe 22 and joint section 21 can again move relative to each other. Access to the pipe brace is unlikely to be practical, so the brace preferably includes some means for release without direct intervention of a worker.

For example, the brace may include one or more degradabie components 10 configured to fail after a relatively short time period, while still allowing sufficient time for installation to be completed.

In one embodiment the fasteners used to hold the two brace halves together are degradabie. For example, the fasteners may be bolts formed from a degradabie 15 metal, such as iron or an iron alloy which is very susceptible to rust. Alternatively, only a section of the bolt's length, or only the nut, could be formed from a degradabie material. Once this part has degraded, the clamping section will release, allowing the pipe 22 to slide with respect to the joint section 21. In general, a sufficient part of the pipe brace must fail such that the pipe brace 20 releases at least one of the pipe 22 and the joint section 21.

Any degradabie material may be used. The material may be a degradabie metal, alloy, plastic or cellulose-based material. The material may degrade by any suitable process, including rusting, oxidation, corrosion, dissolution, 25 biodegradation, softening due to contact with ground water, reactions with ground water or chemicals in the ground, reactions with chemicals applied to the component before or during installation, reactions between parts of the component or between different components of the pipe brace.

Alternatively, for situations such as where the pipe brace is used to provide permanent axial restraint - for example around pipe joints in close proximity to a valve or bend where resultant hydraulic thrust forces can be expected, or in installations on steep grades where concern may exist that conventional rubber ring joints may pull apart - the pipe brace may employ fasteners of a more 35 permanent, enduring, nature. 8 564634 The outer surfaces 33, 34 of the pipe brace may be tapered so as to move more easily through the ground during installation.

The pipe brace 20 must be formed of a material which provides sufficient rigidity during installation of a pipe to which the brace is fitted.

However, where the brace is required to only provide axial restraint during installation the brace may be formed from materials with relatively short lifetimes. 10 Indeed, the entire brace could be formed from a degradabie material. This may allow relatively cheap materials to be used.

The pipe brace shown in Figure 3 has been described principally in the context of a pipe joint as shown in Figures 1 and 2, including two pipes joined by a joint 15 section. However, the pipe brace may be employed with many different types of pipe joint, including for example a simple sliding joint between two pipes of different sizes.

Figure 5 shows a further embodiment of a pipe brace for bracing a first pipe 22 20 and a second pipe 35, which are joined so as to slide with respect each other. The join is achieved simply by having the first pipe 22 of a smaller diameter than the second pipe 35, with a seal 36 provided between the two pipes in the region of the join.

In this embodiment the pipe brace includes a first clamping section 28 substantially similar to that described above. However, instead of an engagement section, the brace includes a second clamping section 28' for clamping to the second pipe 35. The second clamping section 28' includes surfaces 30', 31' similar to the surfaces 30, 31 of the first clamping section, and 30 includes apertures 27' for receiving fasteners to pinch the second clamping section 28' around the second pipe 35.

In this latter embodiment, when a temporary bracing action only is required only one of the first and second clamping sections need release in order to allow 35 sliding movement between the first and second pipes. 9 564634 Again, the pipe brace could be hinged at one side, with only one bolt provided for each clamping section 28, 28*.

In general, any combination of clamping or engagement arrangements, or other means of fastening the brace to the pipes, may be used so long as it is suitable for prevention of sliding movement between the pipes, or between the pipe and joint section.

As sliding movement is prevented, a pipeline including one or more joins braced by a pipe brace may be installed by pushing or pulling through the ground. It is not necessary to dig a trench to receive the pipe, although in some circumstances it may be desirable to drill a bore before pushing or pulling the pipe through that bore.

The inventive pipe brace may be particularly suited to pipeline installation by directional drilling (HDD) where 6m or longer lengths can be used.

As shown in Figures 6a to 6d, an HDD machine 200 is set up to tunnel under a structure or the like, through unstable ground or in any other circumstances where this form of installation is to be preferred. The tunnelling operation creates a bore 201 of suitable diameter. Once drilling is completed (Figure 6b) the first pipe section 101 is attached to the end of the drill rod 202 and is drawn back through the bore 201. As each section 101 is pulled into the bore 201 another section 101 is added. Optimally the length of each pipe section 101 is the same as or a multiple of each drill rod so that as each section 101 is added at one end a drill rod section can be removed (Figure 6c). Once the pipeline 100 has been completed the installation is completed in the usual way (Figure 6d).

During installation a pipe section may be connected to the previous section by some form of sliding join, such as the joins shown in Figures 1 and 5. A pipe brace is then fitted to the sliding join and the pulling of the pipe 101 through the bore 201 can continue. 564634 The temporary pipe brace therefore allows trenchless installation and subsequent release of the brace allows the benefits of sliding pipe joints to be realised.

While the present invention has been illustrated by the description of the 5 embodiments thereof, and while the embodiments have been described in detail, it is not the intention of the Applicant to restrict or in any way limit the scope of the invention to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, representative apparatus and methods, and 10 illustrative examples shown and described. Accordingly, departures may be made from such details without departure from the spirit or scope of the claims. 11

Claims (8)

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A pipe brace configured to prevent movement of a first pipe relative to a pipe joint or a second pipe during pipe installation wherein the brace is configured to fit to a first pipe and a joint section of a second pipe, the first pipe being slidably engaged with the joint section of the second pipe, the brace including an engagement section for engaging with the joint section and a clamping section for clamping to the first pipe to prevent sliding movement of the first pipe relative to the joint section, wherein the pipe brace includes one or more degradabie components, wherein degradation of the degradabie components results in release of the pipe brace to allow movement of the first pipe relative to the pipe joint on the second pipe.

2. A pipe brace according to claim 1 wherein the engagement section is engageable with a protrusion on the joint section of the second pipe.

3. A pipe brace according to claim 2 wherein the joint section includes an internal groove for receiving a seal, the internal groove forming an external protrusion, and the engagement section is configured to engage with a said external protrusion on the joint section of the second pipe.

4. A pipe brace according to any one of the preceding claims wherein the brace includes two clamping sections, one for clamping to each pipe.

5. A pipe brace according to any one of claims 1 to 3 formed in two segments which together wrap around the circumference of the first pipe and the joint section of the second pipe.

6. A pipe brace according to claim 4 or 5 wherein the pipe brace includes one or more fasteners which, in use, join the two segments.

7. A pipe brace according to claim 6 wherein the fasteners joining the two segments are degradabie.

8. A pipe brace according to claim 7 wherein the fasteners are positioned in or near a said clamping section, so as to tighten the clamping section around a pipe and to release the clamping section when the fasteners degrade. 564634 5 10. 11. 10 12. 15 A pipe brace according to any one of the preceding claims wherein the degradabie components are configured to fail in less than 12 months, more preferably less than 3 months. A pipe brace according to any one of the preceding claims shaped to reduce resistance to pushing or pulling of the pipe during installation. A pipe brace according to claim 10 wherein the pipe brace is tapered at one or both ends. A pipe brace according to claim 1 substantially as shown in any one of figures 3 to 5 of the drawings. IPLEX PIPELINES NZ LIMITED By its Attorneys ELLIS | VERBOEKET | TERRY Per: 13