Spline lock restrained pipe joining system for plastic pipe
A restrained pipe joining system for plastic pipe is shown comprising male and female ends each having aligned circumferential grooves which form a canal for passage of a locking keystrap. The keystrap can be formed of PEEK or PEEK reinforced with glass fiber. During manufacture, the female belled end is sequentially formed over a Rieber style gasket and then over a ring-shaped casing member. The casing member is also formed from polymeric composite materials. In some cases, the casing is reinforced with an internal metal band.
1 . A joining system for use in assembling a restrained joint of a first and second sections of plastic pipe, the joining system comprising:
a first section of plastic pipe having a female, belled pipe end with an end opening and having an exterior surface, an interior surface and having a circumferential recess formed in the belled pipe end adjacent the end opening on the interior surface thereof;
at least one bore communicating the exterior surface of the belled pipe end with the interior recess thereof;
a second section of plastic pipe having a mating male plastic pipe end having an interior surface and exterior surface, and wherein the exterior surface has at least one groove formed at one circumferential location thereof which is alignable with the interior recess formed in the belled pipe end when the male pipe end is inserted within the mouth opening of the belled pipe end to form a joint;
a ring-shaped casing member installed within the circumferential recess provided in the belled end of the first section of plastic pipe, the ring-shaped casing member having an inner circumferential surface and an outer circumferential surface and having at least one groove formed at one inner circumferential location on the inner circumferential surface thereof, wherein at least one bore extends from the outer circumferential surface to the groove which is provided on the inner circumferential surface thereof, and wherein the bore of the ring-shaped casing member aligns with the bore in the belled end of the first section of plastic pipe whereby the bores, in combination with the aligned recess and groove, form a canal passageway;
a flexible keystrap adapted to be inserted at least partly through the canal passageway, wherein the flexible keystrap is made of polyether ether ketone (PEEK) or PEEK reinforced with glass fiber;
an associated sealing element co-located within the circumferential recess provided in the first section of plastic pipe adjacent the ring-shaped casing member, the sealing element having an inner circumferential region and an outer circumferential region, the outer circumferential region being arranged to form a seal with the interior surface of the belled end while the inner circumferential region forms a sealing surface for the exterior surface of the mating male pipe section; and
wherein the ring-shaped casing member is made of PEEK, polyethylene terephthalate (PET), or polypropylene (PP) and glass or carbon fiber reinforced versions thereof.
2 . The joining system of claim 1 , wherein the ring-shaped casing member and associated sealing element are both located within the female belled pipe end during manufacture of the pipe in a Rieber style manufacturing operation.
3 . The joining system of claim 2 , wherein the sealing element is located within the circumferential recess of the belled pipe end rearwardly of the ring-shaped casing member, the sealing element having a downwardly extending sealing lip which is contacted by the exterior surface of the mating male plastic pipe during the assembly of a pipe joint.
4 . The joining system of claim 1 , wherein the ring-shaped casing member is is filled with 15 to 30% by weight glass or carbon fiber.
5 . The joining system of claim 1 , wherein the keystrap has a curvature equivalent to 1.4 to 1.6 times the radius of the canal passageway.
6 . A joining system for use in assembling a restrained joint of a first and second sections of plastic pipe, the joining system comprising:
a first section of plastic pipe having a female, belled pipe end with an end opening, an exterior surface, an interior surface, and having a heat and expansion formed interior circumferential recess formed in the belled pipe end adjacent the end opening on the interior surface thereof;
at least one bore communicating the exterior surface of the belled pipe end with the interior circumferential recess thereof;
a second section of plastic pipe having a mating male plastic pipe end having an interior surface and exterior surface, and wherein the exterior surface has at least one groove formed at one circumferential location thereof which is alignable with the interior circumferential recess formed in the belled pipe end when the male pipe end is inserted within the mouth opening of the belled pipe end to form a joint;
a ring-shaped casing member installed within the heat and expansion formed interior circumferential recess provided in the belled end of the first section of plastic pipe, the ring-shaped casing member having an inner circumferential surface and an outer circumferential surface and having at least one groove formed at one inner circumferential location of the inner circumferential surface thereof, wherein at least one bore extends from the outer circumferential surface to the groove which is provided on the inner circumferential surface thereof, and wherein the ring-shaped casing member is positionable so that the bore of the ring-shaped casing member aligns with the bore in the belled end of the first section of plastic pipe, whereby the bores, the at least one groove of the ring-shaped casing member, and the at least one groove of the second section of the plastic pipe form a canal passageway;
a flexible keystrap adapted to be inserted at least partly through the canal passageway when the first and second plastic pipes are joined, wherein the flexible keystrap is made of polyether ether ketone (PEEK) or PEEK reinforced with glass fiber
a ring-shaped elastomeric sealing element installed within the same heat and expansion formed interior, circumferential recess provided in the first section of plastic pipe as the ring-shaped casing member and in contact with the ring-shaped casing member, the sealing element having an inner circumferential region and an outer circumferential region, the sealing the outer circumferential region forming a seal with the interior surface of the belled end of the first pipe and the inner circumferential region forming a seal with the exterior surface of the mating male pipe section when the male pipe end is inserted within the opening of the belled pipe end, the sealing element being installed within the circumferential recess of the belled pipe end rearwardly of the ring-shaped casing member and of the end opening of the bell pipe end;
wherein the ring-shaped casing member has a leading edge and a trailing edge, the trailing edge being provided with a recessed profile which mates with and engages a leading nose portion of the sealing element so that while the sealing element and the ring-shaped casing member are separate elements, the sealing element and the ring-shaped casing member are interengaged with the leading nose portion of the sealing element extending into the recessed profile of the ring-shaped casing member, the interengagement to secure the sealing element within the interior of the circumferential recess; and
wherein the ring-shaped casing member is made of PEEK, polyethylene terephthalate (PET), or polypropylene (PP) and glass or carbon fiber reinforced versions thereof.
7 . The joining system of claim 6 , the sealing element having a downwardly extending sealing lip which is contacted by the exterior surface of the mating male plastic pipe to form a lip seal during the assembly of the coupling.
8 . The joining system of claim 6 , wherein the ring-shaped casing member is filled with 15 to 30% by weight glass or carbon fiber.
9 . The joining system of claim 6 , wherein the keystrap has a curvature equivalent to 1.4 to 1.6 times the radius of the canal passageway.