CA2057605C - Pipe coupling - Google Patents

Abstract

A method and apparatus for coupling pipe, and installing coupled pipe in a trenchless installation, the pipe being adapted for use as a watermain or the like. Lengths of watermain pipe are provided with a bell at each end, and connecting nipples adapted to be received within opposing bells, to effect a fluid-tight seal. As lengths of watermain are urged into a trenchless tunnel, opposing bell-end faces withstand the force being exerted on the pipe sections, so that damage is avoided and a sealed underground pipe installation is economically and quickly effected.

Description

~, Z057605 INTRODUCTORY DESCRIPTION OF THE INVENTION AND PRIOR ART

It is unfortunately common in urban environments for large sections of the streets to be dug up periodically to replace aged and leaking underground piping, or to install new piping. The cost is great even figured solely on manpower and equipment; much greater when snarled traffic (and public aggravation) is included. Trenchless pipeline installation avoids many of the problems listed, but to date the standard widely-used plastic components for water and sewer mains, having bell and spigot joints, have not been appropriate for trenchless use. They become damaged at the joints if attempted to be pipe-jacked ~pushed or pulled into the hole). The present invention ingeniously allows these common components to be installed without damage.
This allows for a great cost saving since before the present invention more expensive pipes joined by more expensive techniques were necessary in trenchless applications. Thus with the present invention the public is likely to get home from work more quickly and find a smaller tax bill in the mail box.
In brief, the invention is as follows: instead of the bell and spigot joint which is now widely used in standard PVC (polyvinyl chloride) watermain and sewer ~, Z()5~605 pipe, the inventor has specified the same pipe but with bells on both ends. This calls for no ~actory retooling, merely a labour motion of turning the pipe during manufacture. During pipe-jacking according to the invention, two pipes are placed end-to-end, the bells line up exactly, and the bells transfer the longitudinal load smoothly. A separate piece of straight (bell-less) pipe, or nipple, has at this point been installed inside the pipes at the joint, and makes liquid-sealing contact against gaskets inside the bells.
These gaskets are already part of the bell-formation process since they are an integral part of the original bell and spigot connection. Now however, two gaskets are flush against the nipple instead of one against a spigot.
The invention resides in the fact that the force of pipe-jacking is not transmitted through the nipple, which is completely isolated from this force. In common PVC bell and spigot configurations, pipe-jacking above a certain short distance causes the spigot and/or its matching bell, to be damanged eventually causing a rupture. A square-shouldered bell might accommodate this, but would be more difficult to make and requires modification of existing manufacturing equipment disproportionate to the size of the market for trenchless installation.

~_, Z057605 In minor variations, the inventor has also devised a bearing ring which can be placed around the nipple between the bells, to ensure no abrasion of the bell surfaces during installation; a bearing and anchor-ring that will also prevent lateral movement of the nipple ~wherein a groove is scored in the nipple to hold the ring); and a custom-molded nipple that contains its own bearing ring and is hence anchored. In all cases the essential bell-to-bell load-bearing of the invention prevails.
A search of the relevant prior art has revealed only pipe-coupling inventions that have a superficial visual resemblance to the present invention, but were not intended for trenchless applications. On examination they can easily be shown to suffer from the same serious flaw as the common bell and spigot PVC:
a rupture would be caused with the heavy end-loading required for trenchless installation. For example, Canadian Patent No. 877,834 (Ellay Enfield) is superficially similar but designed for a different purpose: for the provision of end restraint on pipes installed by conventional means. Any applied end-load would be borne on curved surfaces, and would crack in exactly the same manner as common bell and spigot PVC. As well, the components are not standard, requiring extensive retooling; and the clip _ .~

20S~605 system would dislodge during installation. Finally the size of the pipeline would be determined by the size ~nominal inside diameter) of the nipples, rather than the size of the pipe itself.
Similarly, with the other prior art:
Canadian Patent No. 1,029,416 (Dupont) is intended for repair; Canadian No. 869,429 IA.M.F.) is designed for welding of steel pipe; Canadian No. 635,412 is for threaded metal couplings. In all the foregoing the essential features of this invention are not addressed:
1) they do not isolate the spigot component of the coupling from the pushing force necessary for pipe-jacking or other trenchless pipeline replacement installations; 2) They do not employ existing standard production coupling components. Finally, in ~.S. No.

3,360,283 ~Guthrie), the diameter of the line would be governed by the diameter of the nipple rather than the pipeline itself, and the components are all non-standard relative to existing sewer and water line specifications, necessitating extensive retooling. The stated use of the Guthrie patent is "circuits requiring frequent assembly and disassembly, such as agricultural circuits," and also where "limited space is normally available for installation such as in heating and air conditioning ducts", the question of trenchless end-~ 205760S

loaded installation is not contemplated or addressed.
One object of the present invention is to provide a method and apparatus for pushing jointed plpe comprislng:
(a) a plurality of substantially identical lengths of pipe with integral extruded annular flanges, called bells, on both ends, such that the maximum inside diameter of the bell is greater than the outside diameter of the body of the pipe;
(b) a similar plurality of substantially identical nipples, being shorter lengths of straight pipe, positioned such that there is one nipple inserted between two opposing bells when the longer pipe lengths are coupled end to end; said nipples being bevelled on both ends, and said nipples being shorter in length than the shortest distance between the two inside sloping surfaces of said opposing bells when the ends of the opposing bells are annularly touching; said sloping surfaces being the connecting surface between the maximum inside diameter of bell and minimum inside diameter of the body of the pipe;

(c) a means of forming an annular seal between the outer surface of the nipple and the inner surface of the bell; said seal being appropriate to contain inside . .

~ 20S~605 the pipe whatever is being transported in the pipe;
~ d) a means for longitudinally pushing the end of the coupled line of pipes, or pipeline; said means having sufficient force to move the entire pipeline longitudinally; and (e) means for positioning subsequent nipples and pipes onto the penultimate pipe.
Another object of the invention is to provide a method and apparatus for pushing jointed pipe such as just described in (a) through (e), except that an annular ring, called a bearing ring, is placed between the outer surfaces of the two opposing bells in the coupling, for the purposes of preventing abrasion between said surfaces during installation; said bearing ring being designed so as to effectively transmit the longitudinal pushing force from bell surface.
Another object of the invention is to provide a similar method and apparatus for pushing jointed pipe as that just described in (a) through (e), except that instead of the annular ring just described, an annular groove is machined in the outer surface of the nipple, and an annular ring, called a retainer ring, fashioned to fit securely in the groove; said secure fit in the groove being sufficient to prevent lateral movement of the nipple during installation.

"

~_, Z057605 Another object of the invention is to provide a similar method and apparatus for pushing jointed pipe as that just described in ~a) through (e), except that instead of the separate retainer ring just described, the nipples are fashioned as a single piece with an annular ring extending outwards from their lengthwise midpoint.
A further object of the invention is to provide a means of coupling PVC, that is polyvinyl chloride, gasket-jointed AWWA, that is American Water Works Association, Standard C-900 and CSA B137.3M86 watermain pipe in trenchless installation, comprising:
(a) obtaining said watermain pipe appropriate in diameter and length for the installation being performed, except manufactured with standard bells with standard annular gaskets on both ends instead of on one end only;
(b) obtaining for each length of said watermain pipe one nipple, being a bell-less shorter length of AWWA Standard C-900 watermain pipe; said nipples being bevelled on both ends; said nipples being shorter in length than the shortest distance between the two inside sloping surfaces of opposing bells when the ends of bells of two lengths of longer pipe are annularly touching; outside unbevelled surface of said nipples ~,, 20S760S

being longer in length than the shortest distance between one side sloping surface of one bell and the gasket in the opposing bell; said sloping surfaces being the connecting surface between the maximum inside diameter of bell and the minimum inside diameter of the body of the pipe;
(c~ installing the first length of said double-belled standard C-900 watermain pipe into the intended watermain tunnel using known techniques, such that one bell end is still outside the tunnel;
~d) inserting a nipple into said bell end, such that its outside unbevelled surface extends farther than the gasket in said bell end but not so far as to contact the inside sloping surface of said bell end;
~e) placing another length of double-bell-ended pipe over the extending nipple using known techniques, and maneuvering it, using known techniques, towards the penultimate pipe so that ultimately the bell-end faces of the two pipes touch;
(f) applying tape, including but not limited to common duct tape, annularly around the joint of the two opposing bell-faces to prevent dirt entry into the joint.
~g) pushing against the open end of the last pipe, using known techniques, such that the two pipes move longitudinally into the tunnel;

~ _ .

2(~S7605 ~h) repeating steps ~d) through ~g) of the description until the end pipe has been inserted into the tunnel to complete the length of pipeline desired.
These examples are by way of illustration only, and the process is intended to work equally well with any type of end-loaded installation of jointed tubes.
To the inventor's knowledge, there is no prior art that solves the problem of common component end-loaded installation in a similar manner; therefore, the invention may have applications outside the existing specific use to be described. For this reason, the reader is advised that the contexts discussed in this introduction and the more detailed description to follow are by example only and in no way are intended to limit the scope of the appended claims.
In the following description, reference will be made to the accompanying drawings in which:
Figure 1, a typical bell and spigot gasket-seal joint according to prior art, unassembled;
Figure 2, a typical bell and spigot gasket-sealed joint according to the present invention;
assembled;
Figure 3, a bell, bell, nipple gasket-sealed joint according to the present invention; unassembled;
Figure 4, a bell, bell and nipple gasket-sealed _. . "

~ Z~57605 joint according to the present invention; assembled;
Figure 5, a cross-section of bell, bell and nipple gasket-sealed joint according to the present invention, additionally showing bearing ring and dirt shield tape;
Figure 6, a cross-section of bell, bell and nipple gasket-sealed joint according to the present invention, additionally showing grooved anchored nipple;
Figure 7, additional cross-section of nipple 10according to the present invention shown in Figure 6, clearly exhibiting radial and insert dimension;
Figure 8, a cross-section of bell, bell and nipple gasket-sealed joint according to the present invention, additionally showing nipple over-inserted 15into bell during installation;
Figure 9, simple push trenchless installation method for pipes joined according to the present invention;
Figure 10, simple push trenchless installation 20method for pipes joined according to the present invention;
Figure 11, pulling or indirect pushing installation method for pipes joined according to the present invention;
25Figure 12, pulling or indirect pushing ~ ..~....

installation method for pipes according to the present invention, showing components exploded;
Figure 13, pulling or indirect pushing installation method for pipes jointed according to the present invention, showing full length of operation;
Figure 14, cross-section of molded nipple with integral bearing and anchor ring, according to the present invention, with detail;
Figure 15, cross-section of a bell, bell and nipple gasket-sealed joint according to the present invention, showing molded nipple with integral bearing and anchor ring; and Figure 16 is a detail, in enlarged scale of a bearing ring butted against a bell surface.
Detailed reference will now be made to the drawings in which like reference numerals will identify like parts.
In a first version of the invention, trenchless installation of PVC watermain pipe made to the American Water Works Association (AWWA) Standard C-900 (also CSA B137.3M86~ will be described. This is the predominant type of pipe currently used in municipal watermain installations throughout Canada and the U.S.A.
It should be understood that the invention is also applicable to trenchless installations of any suitable pipe with bell and spigot joints with annular gasket .. - 12 -~" 2~5~605 seals, for example, standard PVC sewer pipe (ASTMD3034, F697; CSA B183.1, B182, known as "PSM" type).
Referring to Figure 3, an adequate number of AWWA Standard C-900 watermain pipes 10 are ordered manufactured with bells 12 on both ends. Inside each bell is annular gasket 14. Enough pipe is obtained for the complete length of the job being considered. For each pipe is also obtained a short length of pipe 16, also called nipple, with spigot on both ends.
As seen in Figure 5, the inside diameter 17 of nipple 16 is equal to the inside diameter 19 of the AWWA
Standard C-900 watermain barrel 18.
The outer diameter 15 of the nipple 16 is less than the inside diameter 13 of bell 12, so that the nipple 16 will fit inside the mouth of bell 12, and snug up against gasket 14 for a fluid-proof seal.
An assembled coupling is illustrated in Figure 4, and in Figure 5. Standard commercially available straight pipe is commonly sold, and has the diameter sizes required in nipples 16. Nipples 16 are also provided with a bevel on both ends 21 ~ see Figure 5) and the provision of such bevels is also readily available commercially. The suggested bevel is about 15 over one inch.
Referring to Figure 8, the maximum length of the ,_~

~_, 2Q57605 nipple 16 is calculated such that it is less than the distance between the sloping shoulders 20 of the two opposing bells 12, so that, as indicated in Figure 8, if the nipple is over-inserted into the one bell during installation such that a bevelled end 21 thereof contacts the inside surface of sloping shoulder 20, the other end of the nipple will not contact the opposing shoulder. Thus, the longitudinal load will still be borne between bell-mouth faces 23, and nipple 16 will not be broken or deformed. Further, the nipple is provided with a minimum length, also illustrated in Figure 8, so that if the nipple is over-inserted to the left, as illustrated in Figure 8, the nipple must be long enough so that its unbevelled outer surface extends beyond gasket 14 in opposing bell 20. This ensures a fluid-tight seal even though the nipple 16 has been over-inserted.
The inventor has devised three further versions of the invention involving the contact of the opposing bell-faces 23; these will be applicable in different situations. Since trenchless installation of the pipeline is identical for all variants, they will be described now and the common installation procedure afterwards.

i Z~57605 It will be understood that relative movement between bell-faces 23 during push or pull installation may result in abrasion. Though likely insufficient to cause damage because bell faces of standard commercially-produced pipe bells are commonly flat, the presence of high spots causing point-loads cannot be discounted. Therefore, in a second version of the invention, referring to Figure 5, an annular bearing-ring 26 is provided between the bell-mouth faces 23, positioned over the nipple 16. Bearing-ring 26 can be fashioned by cutting rings 1/2" and 3/4" wide from suitably sized pipe of polyethylene, PVC, or other suitable material. Rings with inside diameter dimensions to fit closely over C-900 and D3034 PVC
nipples 16 and with outside diameter 15dimensions sufficient to form an ample bearing surface between bell-faces may be cut from standard ASTM F714 polyethylene pipe. Finally, a layer of adhesive tape 26, standard duct tape, is to be applied around the outside of the joint, to prevent dirt from entering the coupling while the pipe is being pushed into place.
In the third version, referring to Figures 6 and 7, an annular groove 31 is machined into the outer surface 30 of nipple 16, and an annular retainer ring 34 is fashioned so that it fits closely within groove 31.
Retainer ring 34 also functions as a bearing ring, and ~ Z(~57605 longitudinal force is again transmitted from bell-mouth face to bell-mouth face through the retainer ring 34.
In this manner, the nipple 16 is entirely prevented from movement during coupling assembly and service, and so cannot contact bell-shoulders 20; yet the nipple 16 bears none of the installation load. In this version, nipple 16 is fashioned from pipe which is thicker than the thickness of barrel pipe 10. Thus, after groove 31 has been machined in the outer wall of nipple 16, the remaining thickness of wall 35 of nipple 16 is still as great as the wall thickness of bell-pipe barrel 18. In the example being described, for installation of AWWA
C-900 Class 100 pressure pipe, nipples 16 are fashioned from Class 150 or 200 standard pipe; for Class 150, nipples 16 are Class 200. Retainer ring 34 is made of PVC or polyethylene or other pipe of appropriate outer and inner diameters, similar to the bearing ring 26 of Figure 5, but with two differences: 1) the inner dimension is now calculated to fit snugly into groove 31, as seen in Figure 6, and so in practice is thicker than the bearing ring 26 of Figure 5; and 2) a slit is cut in retainer ring 34, parallel to the axis of the pipe from which retainer ring 34, so that ring 34 is capable of expansion, when it is slidably placed over nipple 16, and then to be snugly received in the groove _ .. .

of nipple 16.
In the fourth and final version, referring to Figures 14 and 15, the nipple 16 is provided with a unitary bearing and anchor ring 16a. This embodiment ; 5 of nipple 16 is specifically manufactured for this application. If nipple 16a of the embodiment of Figures 14 and 15 is made of PVC, it is conveniently moulded.
As seen in Figure 14, the faces 41 of bearing ring 16a are flat, and project away from the outside wall of nipple 16, at an angle of 90 degrees. As seen in Figure 16, a standard bell face 23 will butt squarely against a bearing face 41 of nipple 16. The outside and inside diameters of nipple 16 are as previously described, that is, equal to the outside and inside of diameters of pipe body 18. As earlier described, tape may be applied around the point of union of nipple 16 and bell-faces 23.
To install all versions, known pushing or pulling (indirect pushing) procedures are used for the various trenchless situations, including: trenchless pipeline replacement (TRS, PIM, Expand-a-Line system);
s1ip lining (installing a new pipeline into an old existing pipeline); pipe-jacking (pushing a pipeline into a bored tunnel).
For example, in Figure 9 simple push installation is shown. sXB pipes 50 (bells on both ~ Z~57605 ends) are shown stacked above ground and in tunnel 52.
Nipples 16 are stacked above ground awaiting installation. Pipes and nipples underground in tunnel have already been joined as per the present invention in a BNB ~Bell-nipple-Bell) coupling indicated generally as 58. A backhoe 51 is in position to push end 55 of the most recently positioned pipe. As the backhoe pushes, Figure 10, all pipes move into the tunnel, and nipples 16 are isolated from longitudinal pushing force, which is transmitted through bell-faces in the coupling, as previously described, and shown in Figures 4, 5, 6, 8 and 15.
One example of another common installation technique, pulling (indirect pushing) is illustrated in Figures 11, 12 and 13. A pipeline replacement tool, indicated generally as 60, surrounds the bell 61 of the first pipe being pulled; in this case over an old existing pipeline 64. Chain 66 attached to the back of the tool runs inside the new pipe to a pushing head 68 immediately behind the most recently added pipe 70 in the pipeline. As the pipeline replacement tool 60 (or a tunnelling tool or boring machine) pulls the chain forward, longitudinal force is applied from thrust plate 69 to end surface 55 of this most recent pipe. The entire pipeline moves into the tunnel, as shown in 2(~57605 Figure 13. Pushing force is born by pipeline identically to previous example using backhoe push, excepting only that in this case force is applied from thrust-plate 69 onto end 55 of the last pipe, instead of from backhoe shovel. Thus, force moves longitudinally through BNB couplings indicated generally as 58, and nipples 16 are isolated and as previously described, have no chance of damaging coupling. This indirect pushing method was the one actually used with the invented coupling at installations in Calgary, Alberta and worked well.
The foregoing is by way of example, and the invention should be limited only by the scope of the appended claims.

Claims (17)

1. Pipe coupling apparatus comprising:
(a) a plurality of substantially identical lengths of pipe with unitary extruded annular recepticle , called bells, on both ends, said bells having a maximum inside diameter greater than the outside diameter of the body of the pipe, and said bells having interior sloping surfaces at the rear of the bell;
(b) a plurality of substantially identical nipples, being short lengths of straight pipe, adapted to be positioned such that one nipple is inserted between and within two of said opposing bells, when said pipes with bell ends are coupled end to end;
(c) said nipples being bevelled on both ends, and said nipples being shorter in length than the shortest distance between the two inside sloping surfaces on said opposing bells when the ends of said opposing bells are annularly touching, said straight unbevelled portions of said nipples being larger than the maximum distance between gaskets positioned within the opposing bells when the pipes are coupled.
(d) said sloping surfaces being the connecting surface between the maximum inside diameter of the bell and the minimum inside diameter of the body of pipe;
(e) sealing means between the outer surface of the nipples and the inner surface of the bells.

2. Apparatus according to claim 1, said sealing means being in the form of gaskets.

3. Apparatus according to claim 1, including bearing means in the form of an annular bearing ring positioned between the outer forces of two opposing bells, the annular bearing ring being adapted to transmit longitudinal pushing forces from one bell face to an opposing bell face.

4. Apparatus according to claim 1, said bearing means comprising an annular groove around the outer surface of the nipples, adapted to receive an annular retainer ring, which extends above the surface of the nipple, and is adapted to engage opposite faces of pipe bells.

5. Apparatus according to claim 1, said nipples being formed with a unitary annular ring extending centrally therefrom, and adapted to engage the opposing faces of pipe bells.

6. A method of coupling PVC, that is polyvinyl chloride, gasket-jointed AWWA, that is American Water Works Association, Standard C-900 and CSA B137,3M86 watermain pipe in trenchless installation, comprising:
(a) obtaining said watermain pipe appropriate in diameter and length for installation being performed, except manufactured with standard bells with standard annular gaskets on both ends instead of one one end only;
(b) obtaining for each length of said watermain pipe one nipple, being a bell-less shorter length of AWWA Standard C-900 watermain pipe; said nipples being bevelled on both ends;

said nipples being shorter in length than the shortest distance between the two inside sloping surfaces of opposing bells when the ends of bells of two lengths of longer pipe are annularly touching; outside unbevelled surface of said nipples being longer in length than the shortest distance between one inside sloping surface of one bell and the gasket in the opposing bell; said sloping surfaces being the connecting surface between the maximum inside diameter of bell and the minimum inside diameter of the body of the pipe;
(c) installing the first length of said double-belled Standard C-900 watermain pipe into the intended watermain tunnel using known techniques, such that one bell end is still outside the tunnel;
(d) inserting a nipple into said bell end, such that its outside unbevelled surface extends farther than the gasket in said bell end but not so far as to contact the inside sloping surface of said bell;
(e) placing one bell of a double-bell-ended pipe over the extending nipple using known techniques, and maneuvering it, using known techniques, towards the penultimate pipe so that ultimately the bell-end faces of the two pipes touch;
(f) applying tape, including but not limited to common duct tape, annularly around the joint of the two opposing bell-faces to prevent dirt entry into said joint;

(g) pushing against the open end of the last pipe, using known techniques, such that the two pipes move longitudinally into the tunnel;
(h) repeating steps (d) through (g) of this description until enough pipe has been inserted into the tunnel to complete the length of pipeline desired.

7. A method according to claim 6, wherein the tunnel is a straight line.

8. A method according to claim 6, wherein the longer lengths of pipe are of any plastic, PVC, or similar material commonly used for watermain or sewer pipe installation.

9. A method according to claim 6, wherein the longer lengths of pipe are of any plastic, PVC, or similar material commonly used for watermain or sewer pipe installation, and wherein said lengths of pipe are formed from commonly commercially available stock components intended for bell and spigot joints with gasket seals, such that the only manufacturing change necessitated for these components is having bells on both ends instead of only one end.

10. A method according to claim 6, except that after step (d), and before step (e), an annular ring, called a bearing ring, is placed between the outer surfaces of the two opposing bells in the coupling, for the purposes of preventing abrasion between said surfaces during installation; said bearing ring being designed so as to effectively transmit the longitudinal pushing force from bell surface to opposing bell surface; said bearing ring being cut from polyethylene, PVC, or other appropriate material; and except that in step (e) said bell-end faces when in finished coupled position touch the bearing ring surface and not each other; and except that in step (f) said tape is applied to annularly to cover the entire joint of the bearing ring and the bell faces.

11. A method according to claim 6, except and said nipples have been machined with an annular groove around their midpiont, and an annular ring, called a retainer ring, fashioned to fit securely in the groove, and extends outwards above the surface of the nipple such that said ring extends between the outer surfaces of the two opposing bells in the coupling sufficient to prevent abrasion between said surfaces during installation and to effectively transmit the longitudinal pushing force from bell surface to opposing bell surface; said secure fit in the groove being sufficient to prevent lateral movement of the nipple during installation; and except that in step (e) said bell-end faces when in finished coupled position, touch the retainer ring surface and not each other; and except that in step (f) said tape is applied to annularly to cover the entire joint of the retainer ring and the bell faces.

12. A method according to claim 11, wherein the nipples are fashioned from pipe sufficiently thick so that after machining said groove the remaining thickness of the nipple wall is at least as thick as the thickness of the wall of the straight sections of the longer pipes.

13. A method according to claim 11, wherein the longer pipes are pressure pipe including, but not limited to, AWWA C-900 Class 100 or Class 150 pressure pipe, and the nipples are of the same material and specifications but one or two classes higher, including, but not limited to, AWWA C-900 Class 150 or Class 200 pressure pipe, so that after machining said groove, the remaining thickness of the nipple wall is at least as thick as the thickness of the wall of the straight sections of the longer pipes.

14. A method and apparatus according to claim 6, except that the nipples have been fashioned as a single piece with an annular ring extending outwards from their length-wise midpoint between the outer surfaces of the two opposing bells in the coupling, sufficient to prevent abrasion between said surfaces during installation and to effectively transmit the longitudinal pushing force from bell surface to opposing bell surface, and to prevent lateral movement of the nipple during installation; and except that in step (e) said bell-end faces when in finished coupled position, touch the annular ring extending from the nipple and not each other; and except that in step (f) said tape is applied to annularly to cover the entire joint of the nipple and the bell faces.

15. A method according to claim 10, wherein the longer lengths of pipe are of any plastic, PVC, or similar material wherein used for watermain or sewer pipe installation, and wherein said lengths of pipe are formed from commonly commercially available stock components intended for bell and spigot joints with gasket seals, such that the only manufacturing change necessitated for these components is having bells on both ends instead of only one end.

16. A method according to claim 11, wherein the longer lengths of pipe are of any plastic, PVC, or similar material commonly used for watermain or sewer pipe installation, and wherein said lengths of pipe are formed from commonly commercially available stock components intended for bell and spigot joints with gasket seals, such that the only manufacturing change necessitated for these components is having bells on both ends instead of only one end.

17. A method according to claim 14, wherein the longer lengths of pipe are of any plastic, PVC, or similar material commonly used for watermain or sewer pipe installation, and wherein said lengths of pipe are formed from commonly commercially available stock components intended for bell and spigot joints with gasket seals, such that the only manufacturing change necessitated for these components is having bells on both ends instead of only one end.