Coupling for lined pipe

Claim 2

A coupling joint interconnecting two lengths of metal pipe comprising: (a) first pipe means having a plastic liner on the internal surface thereof, the end face of said plastic liner substantially coterminous with the end face of said pipe means; (b) an end face collar comprising a tubular plastic body, the external diameter thereof substantially conforming to the internal diameter of said liner in said first pipe means and having a radially extending flange at one end thereof, said end face collar positioned within the open end of said first pipe with said radially extending flange adjacent the end face of said first pipe means; and (c) second pipe means having an internal diameter at the open end thereof less than the external diameter of said first pipe means and having a plastic liner on the internal surface thereof, the end of said plastic liner terminating within said second pipe means at a point removed from the open end thereof, wherein the end of said first pipe means is telescopically interference fit within the open end of said second pipe means and said radially extending flange overlaps said plastic liner in said second pipe means.

Claim 3

The coupling joint defined in claim 1 wherein the mouth of said second pipe means is radially inwardly deformed to form a groove in and interlock with said first pipe means.

Claim 4

The coupling joint defined in claim 2 wherein said tubular plastic body extends into said first pipe means past said groove.

Claim 7

The method set forth in claim 4 including the step of deforming at least a portion of the mouth of said other pipe section inwardly sufficiently to form a corresponding groove in said one pipe section, thereby mechanically interlocking said pipe sections.

Claim 10

The method set forth in claim 6 including the step of deforming at least a portion of said coupling sleeve inwardly sufficiently to form a corresponding groove in said pipe section, thereby mechanically interlocking said pipe sections and said coupling sleeve.

Claim 11

The method set forth in claim 6 including the steps of forming an annular recess in the internal surface of said coupling sleeve, positioning a plastic band within said recess in said coupling sleeve, and positioning said flanges of said plastic collars in abutting relationship within said plastic band.

Claim 12

The method set forth in claim 6 including the step of applying a bonding agent to the ends of said pipe sections and to the flanges of said plastic collars prior to insertion of said pipe section ends into said coupling sleeve.

Claim 13

The method set forth in claim 6 including the step of cleaning and sizing the ends of said pipe sections prior to insertion of the pipe section ends into said coupling sleeve.

Claim 14

The coupling joint defined in claim 1 wherein said radially extending flange includes a substantially axially extending portion extending from the outer edge thereof.

Claim 15

An interference fit coupling joint interconnecting two sections of plastic lined metal pipe comprising: (a) a plastic end face collar positioned within the end of each pipe section, said end face collar comprising a cylindrical body with its outer surface mating with the inner surface of the liner in the end portion of the plastic liner and having a flange radially extending from one end thereof, said flange mating with the end face of said pipe section; and (b) a coupling sleeve comprising a cylindrical body having an internal diameter less than the external diameter of said pipe sections prior to assembly of said coupling joint surrounding the open ends of said pipe sections and maintaining the end faces of said end face collars in abutting relationship.

Claim 16

An interference fit coupling joint interconnecting two sections of plastic lined metal pipe comprising: (a) a plastic end face collar positioned within the end of each pipe section, said end face collar comprising a cylindrical body with its outer surface mating with the inner surface of the liner in the end portion of the plastic liner and having a flange radially extending from one end thereof, said flange mating with the end face of said pipe section; and (b) a coupling sleeve comprising a cylindrical body having an internal diameter less than the external diameter of said pipe sections prior to assembly of said coupling joint surrounding the open ends of said pipe sections and maintaining the end faces of said end face collars in abutting relationship.

Claim 17

The coupling joint defined in claim 12 wherein said coupling sleeve includes a substantially centrally located annular recess in its internal surface with a plastic band positioned within said recess, and the abutting end faces of said end face collars are positioned within said plastic band.

Claim 18

The coupling joint defined in claim 12 wherein at least a portion of said coupling sleeve is inwardly depressed to mate with a corresponding depression in the pipe section to mechanically interlock said coupling sleeve and said pipe section.

Claim 19

The coupling joint defined in claim 12 wherein the ends of said coupling sleeve are radially compressed to form a corresponding annular groove in each of said pipe sections and thereby mechanically interlock said coupling sleeve and said pipe sections in a fixed relationship.

Claim 20

The coupling joint defined in claim 12 wherein said plastic end face collars are bonded to said plastic liners and to each other.

Claim 21

Coupling joint defined in claim 13 wherein said plastic end face collars are bonded to said plastic liners, to each other and to said plastic band.

Claim 22

An interference fit coupling joint interconnecting first and second lengths of metal pipe, said first pipe having a bell on one end thereof and said second pipe having a pin end telescopically inserted within said bell, the external diameter of said pin end being greater than the internal diameter of said bell prior to assembly of said coupling joint, comprising: (a) a plastic liner bonded to the internal surface of said first pipe and terminating in the throat of said bell; (b) a plastic liner bonded to the internal surface of said second pipe and terminating substantially in the plane of the end face of said pin end; and (c) an end face liner comprising a tubular plastic body, the external diameter thereof substantially comforming to the internal diameter of the liner in the pin end of said second pipe and having a radially extending flange at one end thereof with a substantially axially extending portion extending from the outer edge thereof, positioned within said pin end with the radially extending flange adjacent the end face of said second pipe and said axially extending portion of said flange overlapping said liner in the throat of said bell.

Claim 23

An interference fit coupling joint interconnecting first and second lengths of metal pipe, said first pipe having a bell on one end thereof and said second pipe having a pin end telescopically inserted within said bell, the external diameter of said pin end being greater than the internal diameter of said bell prior to assembly of said coupling joint, comprising: (a) a plastic liner bonded to the internal surface of said first pipe and terminating in the throat of said bell; (b) a plastic liner bonded to the internal surface of said second pipe and terminating substantially in the plane of the end face of said pin end; and (c) an end face liner comprising a tubular plastic body, the external diameter thereof substantially comforming to the internal diameter of the liner in the pin end of said second pipe and having a radially extending flange at one end thereof with a substantially axially extending portion extending from the outer edge thereof, positioned within said pin end with the radially extending flange adjacent the end face of said second pipe and said axially extending portion of said flange overlapping said liner in the throat of said bell.