LOCKING FLUSH JOINT PIPE CONNECTION AND METHOD

Abstract

A method of borehole pipe installation begins with unfinished stick pipes brought to the installation site and then machined or cut to form male and female ends. The pipe ends are then locked together to form a flush joint. The lock can be provided via a groove cut into one of the ends for receipt of a lock gasket, which secures and seals the joint when the pipes are pushed together, and prevents the pipes from being pulled apart. Alternatively, to the groove and lock gasket, the ends can be glued and screwed together, with the screws allowing the joined pipes to be pulled through the borehole before the glue is dry. The pipe joint has flush exterior and interior surfaces to minimize borehole clearance and maximize fluid flow through the pipe assembly.

Claims

1: A method of making a flush pipe joint in the field for connecting first and second stick pipes together in a pit for pulling into a borehole, comprising: bringing the first and second stick pipes with unfinished ends to a borehole installation site; then cutting an exterior portion on one end of the first pipe stick to create a male end; cutting an interior portion on one end of the second pipe stick to create a female end; then pushing the male and female ends together in the pit to create a flush pipe joint having smooth interior and exterior pipe surfaces; and locking the male and female ends together using adhesive so that the pipes can be pulled into the borehole, and defining a longitudinal axis for the pipe joint; and extending screws into the pipes in a direction substantially perpendicular to the longitudinal axis so as to secure the pipes for pulling into the borehole while the adhesive cures.

2.-3. (canceled)

4: The method of claim 1 further comprising cutting a groove into one of the male and female ends, and then placing a locking gasket into the groove before the male and female ends are pushed together.

5: The method of claim 4 wherein the male and female ends are free from a sealing compound.

6: The method of claim 1 wherein the pipe joint is free of changes in diameter on the both the interior and exterior pipe surfaces.

7: The method of claim 1 wherein the male and female ends butt together.

8: The method of claim 1 further comprising marking the pipe sticks with indicia after being brought to the borehole site to designate usage of the pipe sticks.

9: The method of claim 1 wherein the male and female ends are pushed together without use of a bell socket.

10: The method of claim 1 wherein the male and female ends are joined together without threads, sleeves, clamps, bolts, thrust blocks and splines.

11: The method of claim 1 further comprising forming chamfers on the male and female pipe ends.

12: The method of claim 1 further comprising color coding at the borehole installation site the first and second pipe sticks to identify material to be carried in the pipe sticks.

13. (canceled)

14: The method of claim 1 wherein the pipes are cut at the borehole installation site to fit a project design.

15.-20. (canceled)

21: A method of joining pipes at a field site having a borehole, comprising; forming at the field site male and female ends on unfinished ends of a pair of pipes; then matingly engaging the male and female ends to connect the pipes, and defining a longitudinal axis for the pipes; then locking the pipe ends together with screws extending into the pipes substantially perpendicular to the longitudinal axis; and then installing the connected pipes into the borehole.

22. (canceled)

23: The method of claim 21 wherein the connected pipes have a flush joint.

24: The method of claim 21 further comprising placing an indicia on the pipes at the field site to identify material to be carried through the pipes.

25: The method of claim 21 wherein the joined pipes have a constant inside diameter and a constant outside diameter.

26. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIG. 1 is a sectional exploded perspective view of first and second stick pipes, with unfinished ends, for use in the method according to the present invention.

[0022] FIG. 2 is a sectional exploded perspective view of first and second stick pipes after the ends are machined, disassembled, ready for coupling, according to a first embodiment of the present invention.

[0023] FIG. 3 is a sectional view of the disassembled pipes shown in FIG. 2.

[0024] FIG. 4 is a sectional view showing the first and second pipes joined together, according to the present invention.

[0025] FIG. 5 is a sectional view, similar to FIG. 4, of an alternative embodiment of the invention, wherein the pipes are lockingly joined using adhesive and screws, rather than the groove and locking gasket.

[0026] FIG. 6 is a schematic flowchart for the first embodiment method of the present invention, wherein first and second stick pipes are machined and then joined at the borehole pipe installation site.

[0027] FIG. 7 is a schematic flowchart for the second embodiment method of the present invention, wherein the first and second pipe segments are machined and then joined using adhesive and screws at the borehole installation site.

DETAILED DESCRIPTION OF THE INVENTION

[0028] The finished pipe assembly 10 begins with a first stick pipe 12 and a second stick pipe 14 which are brought to a trenchless or borehole pipe installation site. The pipe segments 12, 14 are preferably plastic, such as PVC. The first and second stick pipes 12, 14 have unfinished ends 16, 18, respectively when the stick pipes are delivered to the installation job site. At the job site, the first stick pipe 12 is machined, for example using a field cutting portable router machine, to form a female end 20, and the second stick pipe 14 is machined to form a male end 22. Then, an annular groove 24 is formed into one of the female or male ends 20, 22. Preferably, the groove has a minimal depth, so as to maximize or maintain a sufficient thickness of the pipe wall. Also, the groove is formed with square inside corners. While the drawings show the groove 24 formed on the internal surface of the female end 20, it is understood that, alternatively, the groove 24 can be formed on the external surface of the male end 22. After the groove 24 is cut, a close tolerance fit locking gasket 26 is inserted into the groove, and then the pipes 23, 14 are pushed together to lock and create the flush joint. “Close tolerance fit” means that the gasket 26 fits tightly in the groove 24, which helps retain the gasket in the groove as the pipes are pushed together. To achieve the desired tight fit, the gasket 26 has a profile, or cross section, which substantially matches the profile cross section of the groove 24, so that the gasket engages the opposite sides of the groove, and extends a minimal distance out of the groove, as shown in FIGS. 2-4.

[0029] FIGS. 5 and 7 show an alternative to the locking gasket 26, wherein adhesive or glue 25 is applied to either or both ends 20,22 prior to joining first and second pipe segments 12, 14 together. The adhesive 25 dries or cures after the segments are joined to seal and lock the segments together. Screws 27 may be used to hold the segments together after gluing, so that the joined segments can be pulled through the borehole without waiting for the adhesive to dry. The adhesive lock joint eliminates the need for the groove 24 and the lock gasket 26.

[0030] A beveled or chamfered edge 28 is formed on the female end 20, and a beveled or chamfered edge 30 is formed on the male end 22. The beveled edges 28, 30 can be formed before or after the groove 24 is cut to facilitate alignment of the pipes 12, 14 for joining After the first and second stick pipes 12, 14 are machined on site to create the female and male ends 20, 22, the groove 24, and the beveled edges 28, 30, the pipes can be joined by pushing the female and male ends 20, 22 together until the ends abut the corresponding shoulders 32, 34 on the respective ends 20, 22 to form a butt joint. As seen in FIG. 4, the pipe assembly 10 created by the connected pipes 12, 14 has a flush interior surface 36, and a flush exterior surface 38. Thus, the interior surface 36 of the pipe assembly 10 has a constant, unchanged inside diameter on both sides of the pipe joint, as well as a constant, unchanged exterior diameter on both sides of the pipe joint. The lock gasket 36 only allows movement of the pipes 12, 14 in one direction, and prevents the first and second pipes from being pulled apart, thus eliminating the need for an exterior sleeve, internal threads, bolts, clamps, thrust blocks, bell sockets, or other connection components which would change the internal or external diameters of the flush butt joint of the pipe assembly 10. The lock gasket 26 also eliminates the need for any sealant, such as joint compound, being used on the coupling of the pipes 12, 14.

[0031] FIG. 6 schematically illustrates the method of the first embodiment of the present invention, which takes place totally at the jobsite wherein the pipe assembly 10 is to be installed into a borehole. The stick pipes 12, 14 are brought to the borehole site, wherein the female and male ends 20, 22 are cut or machined. Then, the groove 24 is cut or machined to either the male or female end and the lock gasket 26 is installed. Then, the pipes are pushed together to create a flush butt joint with smooth internal and external surfaces. Though not shown in FIG. 5, it is understood that the beveled edges 28, 30 can be formed in the female and male ends 20, 22 any time after the ends are machined. Also, it is understood that the stick pipes 12, 14 can be cut at the job site to any desired length.

[0032] FIG. 7 schematically illustrates the method of the second embodiment of the present invention, which also is fully performed at the pipe installation site. The second method is the same as the first method, except that the gasket 26 is replaced by the adhesive 25, and optionally the screws 27. Both methods shown in FIGS. 6 and 7 provide an internal and external flush joint pipe that can be used in high pressure applications, such as municipal water lines, without blowing or pulling apart. Both methods also minimize the length of the installation pit, since the pipes can be cut to shorter lengths, thereby reducing construction costs.

[0033] These methods of cutting, machining, and joining pipes in the field to fit job site limitations and minimize pit sizes also eliminates wasted pipe, as any section that is cut can later be machined and joined to other pipe sections, since bell socket connections are not employed.

[0034] Preferably the pipe sticks or segments 12, 14 are marked at the job site to designate the usage of the pipe. For example, the pipes 12, 14 can be color coded to indicate specific materials to flow through the pipe assembly 10, and/or for the pressure rating of the pipe. For example, a first color can be used for potable water and a second color can be used for sewer water or other liquids. The color marking can be added to the pipes 12, 14 before or after cutting, using any suitable material, such as a die stamped, brushed or otherwise applied to the pipe. The marking can be in any form and can be continuous or discontinuous along the pipe, such as a stripe, a spiral line, a series of separate marks, or any other easily identifiable designation. Preferably, the marking or markings extend along the length of the pipe, and at least along a top portion, so that an installer can see the indicia from above the borehole pit, without moving or rotating the pipe. Apply the mark or indicia at the work site allows the manufacturer to produce and stock a single color pipe (preferably white), thereby minimizing manufacturing costs.

[0035] It is understood that the drawings are not drawn to scale, and the thickness of the walls of the pipes 12, 14 may be different than that shown in the drawings.

[0036] The pipe assembly 10 provides an internally and externally flush joint which maximizes fluid flow through the pipe assembly without turbulence and minimizes the clearance required to push or pull the pipe assembly through the borehole. Also, by bringing unfinished stick pipes to the jobsite and then finishing the pipe ends for joining at the jobsite, greatly reduces the cost of labor, materials and excavating pipe pits are all reduced. Also, customizing of the pipe assembly length on site further simplifies the installation process, and reduces time and costs.

[0037] The invention has been shown and described above with the preferred embodiments, and it is understood that many modifications, substitutions, and additions may be made which are within the intended spirit and scope of the invention. From the foregoing, it can be seen that the present invention accomplishes at least all of its stated objectives.