Pipe Puncture Tool

FIELD OF THE INVENTION

[0001 ] The present invention relates generally to tools and apparatus for penetrating a new hole into an existing operational pipe carrying gasses or fluids for the purpose of connecting an additional pipe for carrying such fluids of gas.

BACKGROUND

[0002] Polymer pipes, and in particular polyethylene (PE) pipes, are very popular for domestic, mining, industrial and irrigation applications, and often provide advantages over alternative piping solutions such as iron, steel or cement pipes. For example, PE pipes are commonly used for both above and below ground pipelines, including pressurised fluid or gas supply pipe applications, and for sewerage pipe applications.

[0003] Such diverse pipe applications often involve rather complex piping networks, some including many kilometres of pipeline. Commonly, during their usable lifetime many such piping networks require maintenance, modifications, or the creation of branched sub-networks. Such work often requires the creation of a “T” junction or branch line connection extending from the existing main pipe length.

[0004] However, retrofitting a new “T” junction to an existing pipeline often can be difficult, expensive, and time consuming. For example, such pipelines often need to be interrupted during such retrofitting, requiring all pipeline flow to be stopped and any pipeline pressurisation to be released thereby cutting in a new “T” junction into the existing pipe.

[0005] Alternatively, a “Hot Tap Drill” branch connection can be installed with a saddle connection, where the saddle is welded to the pipe with a valve. Typically, a “Hot Tap” cutting tool is sealed to the branch connection, passes through a valve and cuts into the existing pipe. The drill is then retracted back past the valve, the valve isolated and the hot tap tool recovered.

[0006] Further, such retrofitting can contaminate the pipeline network with cutting waste created when connecting the new pipe to the existing pipe, or from dirt, ground fluid or other pollutants.

[0007] An improved system is therefore required for connecting a pipe to create a pipe branch reducing cutting waste.

OBJECT OF THE INVENTION

[0008] It is an object of the present invention to overcome and/or alleviate one or more of the disadvantages of the prior art or provide the consumer with a useful or commercial choice.

SUMMARY OF THE INVENTION

[0009] In a first aspect, although it need not be the only or the broadest aspect, the invention resides in a pipe puncture system, comprising: a drive shaft having a distal end and a driven end; a hole cutter connected to the distal end of the drive shaft; an actuator connected to the driven end of the drive shaft; and a base section that receives the hole cutter and the drive shaft; wherein in use the base section seals a space between a pipe and the actuator, enabling a pressure in the pipe to be maintained after the hole cutter perforates the pipe.

[0010] Preferably, the base section includes a valve.

[0011 ] Preferably, the valve is positioned between a pipe end and an actuator end of the base section, enabling the hole cutter to be a) retracted away from the pipe inside the base section to a position between the valve and the actuator end, and then b) sealed from a perforation in the pipe by closure of the valve.

[0012] Preferably, the base section is removably connectable to the actuator using at least one fastener. [0013] Preferably, the actuator is a hydraulic, pneumatic or mechanical actuator.

[0014] Preferably, the actuator comprises an adjustable collar that is clampable to the drive shaft, enabling an operational length of the drive shaft to be varied.

[0015] Preferably, the hole cutter comprises a plurality of shark-tooth shaped blades.

[0016] Preferably, the hole cutter comprises blades that define a cylindrical cutting edge.

[0017] Preferably, the base section comprises a saddle that is connectable to the pipe.

[0018] Preferably, the saddle is weldable to the pipe.

[0019] Preferably, the pipe is a polymer pipe.

[0020] Preferably, the pipe is a polyethylene (PE) pipe.

[0021 ] Preferably, the actuator effects translational but not rotational motion of the drive shaft relative to the pipe.

[0022] Preferably, the pipe comprises pressurised fluid or gas.

[0023] Preferably, the actuator is connectable to the base section via a stub flange.

[0024] Preferably, an O-ring positioned in a centre hole of the stub flange seals against an outer surface of the drive shaft.

[0025] Preferably, the hole cutter is hollow and comprises a cutting edge having an inside bevel, enabling a biscuit cut from the pipe to be compressed during cutting by the inside bevel, and thus the biscuit is retained inside the hole cutter during retraction of the hole cutter away from the pipe.

[0026] Preferably, the cutting edge comprises a double bevel.

[0027] Preferably, the base section forms the base of a high-point vent in the pipe following removal of the actuator and the hole cutter from the base section.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] To assist in understanding the invention and to enable a person skilled in the art to put the invention into practical effect, preferred embodiments of the invention are described below by way of example only with reference to the accompanying drawings, in which:

[0029] FIG. 1 is a side view of a pipe perforation system, according to some embodiments of the present invention.

[0030] FIG. 2 is a sectional view of Section D-D from FIG. 1 .

[0031 ] FIG. 3 is a further side view of components of the pipe perforation system FIG. 1 , excluding the base section.

[0032] FIG. 4 is a close up view of the hole cutter of FIG. 1 , according to some embodiments of the present invention.

[0033] FIG. 5 is another close up view of the hole cutter of FIG. 1 , showing blades cutting through the outer surface of a pipe.

[0034] FIG. 6 is a close up view of a blade of the hole cutter of FIG. 1 cutting into the wall of a pipe, according to some embodiments of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0035] The present invention relates to an improved pipe cutting system. Elements of the invention are illustrated in concise outline form in the drawings, showing only those specific details that are necessary to understanding the embodiments of the present invention, but so as not to clutter the disclosure with excessive detail that will be obvious to those of ordinary skill in the art in light of the present description.

[0036] In this patent specification, adjectives such as first and second, inside and outside, above and below, longitudinally and transverse, top and bottom, upper and lower, rear, front and side, etc., are used solely to define one element or method step from another element or method step without necessarily requiring a specific relative position or sequence that is described by the adjectives. Words such as “comprises” or “includes” are not used to define an exclusive set of elements or method steps. Rather, such words merely define a minimum set of elements or method steps included in a particular embodiment of the present invention. [0037] According to one aspect, the present invention is defined as a pipe perforation system, comprising: a drive shaft having a distal end and a driven end; a hole cutter connected to the distal end of the drive shaft; an actuator connected to the driven end of the drive shaft; and a base section that receives the hole cutter and the drive shaft; wherein in use the base section seals a space between a pipe and the actuator, enabling a pressure in the pipe to be maintained after the hole cutter perforates the pipe.

[0038] Advantages of some embodiments of the present invention include a system that enables a T-junction or “saddle Connection” to be formed in a pressurised pipe without the need to depressurise or stop liquid or gas flow in the pipe.

[0039] Further advantages of some embodiments include the ability to cut a hole in a pipe wall without creating pipe waste.

[0040] Still other advantages of some embodiments include the ability to cut a hole in a pipe wall without damaging or collapsing the pipe wall.

[0041 ] Those skilled in the art will appreciate that not all the above advantages are necessarily included in all embodiments of the present invention.

[0042] FIG. 1 is a side view of a pipe perforation system 100, according to some embodiments of the present invention. The system 100 includes an actuator 105 that receives a driven end of a drive shaft 110, where the driven end of the drive shaft 110 is clamped to the actuator 105 using a radial collar 112. The drive shaft 110 then extends through a base section 115, and a distal end of the drive shaft 110 is connected to a hole cutter 120.

[0043] The hole cutter 120 is shown projecting through a cylindrical pipe 125, such as a pressurised fluid or gas pipe, to an internal cavity of the pipe 125. An end view of the cylindrical pipe 125 is illustrated. [0044] A curved saddle 130 enables sealing of the base sectionl 15 against an external surface of the existing pipe 125.

[0045] The base section 115 further includes a valve 135, and a welded flange 140 is spaced away from the valve 135 enables connection of the actuator 105. The welded flange 140 enables removable connection of the base section 115 to the actuator 105 using, for example, radial bolts 145.

[0046] An extension of the base section 115 between the valve 125 and the stub flange 140 defines a pressure lock 150 into which the hole cutter 120 can be retracted.

[0047] FIG. 2 is a sectional view of Section D-D from FIG. 1 , further illustrating the system 100.

[0048] A vent valve 201 can be used to de-pressure the space above the valve 135, with the valve 135 closed, such that the hole cutter 120 can be removed by unbolting it at the stub flange 140.

[0049] During use of the system 100, a prospective location for a hole in the pipe 125, such as for connection to a T-junction, is first identified. The saddle 130 of the base section 115 is then sealed over and around the location for the hole. For example, an underside of the saddle 130 can comprise a layer of polyethylene or other plastic that is then welded to the surface of the pipe 125 using an electrical, chemical or mechanical process. Other connection processes, such as mechanical straps around pipe 125, also can be used to robustly connect the saddle 130 to the pipe 125.

[0050] Depending on a length of the base section 115, the drive shaft 110 is then clamped to the actuator 105 using the radial collar 112, ensuring adequate travel of the hole cutter 120 between a starting position inside the base section 115 and a finishing position inside the pipe 125.

[0051 ] Next, the hole cutter 120 and drive shaft 110 are directed into the base section 115 and the actuator 105 is bolted to the base section 115 using the radial bolts 145. Then, with the valve 135 in an open position, the actuator 105 is activated, which forces the drive shaft 110 and the hole cutter 120 toward an external surface of the pipe 125. The hole cutter 120 then cuts through the pipe 125 using a smooth translational motion, and without rotation of the cutter 120.

[0052] Cutting through a wall of the pipe 125 results in a pressure equalisation, of gas or liquid depending on the contents of the pipe 125, between the interior cavity of the pipe 125 and an interior cavity of the base section 115. One or more O-rings positioned in a centre-hole of the stub flange 140 seal against the external surface of the drive shaft 110 and prevent pressurised liquid or gas leaking from the base section 115.

[0053] Next, the radial collar 112 is loosened from the drive shaft 110 and the hole cutter 120 is retracted away from the pipe 125 and into the pressure lock 150 between the valve 135 and the actuator end of the base section 115. The valve 135 is then closed, which seals the pressure lock 150 from the internal cavity of the pipe 125. The vent valve 201 is then opened to release pressure between the valve 135 and the flange 140.

[0054] The actuator 105 then can be unbolted from the base section 115 and removed. The base section 115 is then able to function as a base of a T- junction in the pipe 125. For example, a pipe branch (not shown) or an apparatus such as a high-point vent (not shown) can be connected to the stub flange 140. Finally, the valve 135 can be re-opened, enabling a flow from or to the pipe 125 through the perforation in the pipe 125 formed beneath the saddle 130.

[0055] FIG. 3 is a further side view of components of the pipe perforation system 100, excluding the base section 115. Those skilled in the art will appreciate that the actuator 105 can be of various designs including, for example, hydraulic, pneumatic or mechanical actuator designs, which can generate linear motion of the drive shaft 110 toward the pipe 125.

[0056] FIG. 4 is a close up view of the hole cutter 120, according to some embodiments of the present invention. As shown, the hole cutter 120 includes two shark-tooth shaped blades 405, 410 that are displaced from each other by 180 degrees. The blades 405, 410 enable the cutter 120 to readily puncture a typical polyethylene (PE) pipe, such as a typical 16 to 40 mm diameter PE gas pipe, through translational motion of the cutter 120 into the pipe and without requiring rotation of the cutter 120. Alternative blade designs can be scaled and tuned to cut various sizes of holes through various types of polymer or other non-brittle pipes.

[0057] FIG. 5 is another close up view of the hole cutter 120, showing the blades 405, 410 cutting through the outer surface of a pipe 125.

[0058] FIG. 6 is a close up view of the blade 405 of the hole cutter 120, according to some embodiments. As shown, a cutting edge of the blade 405 comprises a double bevel, which assists in efficiently cutting through the pipe 125 without generating swarf, and without deforming the blade 405 or collapsing the wall of the pipe 125.

[0059] Further, the angle of the inside bevel 605 on the blade 405 causes an oval biscuit that is cut away from the pipe 125 to be compressed during cutting and thus retained inside a hollow portion of the cutter 120 during retraction of the cutter 120 away from the pipe 125. The biscuit then can be discarded, leaving a clear hole in the pipe 125 with no swarf or other waste inside the pipe 125 or the base section 115. Alternatively, the absence or minimisation of the angle on the outside of bevel 605 can ensure that the hole cutter 120 does not compress material outwardly, which can reduce drag on the pipe 125 as the blade 405 traverses the pipe 125 during and after cutting.

[0060] Those skilled in the art will appreciate that various components of embodiments of the present invention can be made of various materials and as various integrated or non-integrated designs.

[0061 ] The above description of various embodiments of the present invention is provided for purposes of description to one of ordinary skill in the related art. It is not intended to be exhaustive or to limit the invention to a single disclosed embodiment. Numerous alternatives and variations to the present invention will be apparent to those skilled in the art of the above teaching. Accordingly, while some alternative embodiments have been discussed specifically, other embodiments will be apparent or relatively easily developed by those of ordinary skill in the art. Accordingly, this patent specification is intended to embrace all alternatives, modifications and variations of the present invention that have been discussed herein, and other embodiments that fall within the spirit and scope of the above described invention.