Method of and joint for coupling thermoplastic pipes

• US 20010048223A1
• Filed: 06/19/2001
• Published: 12/06/2001
• Est. Priority Date: 05/28/1996
• Status: Abandoned Application

• Current Assignee: C&S Intellectual Properties LLC
• Original Assignee: C&S Intellectual Properties LLC
• Inventors: Campbell, Steve
• Application Number:
  US09/884,533
• Publication Number:
  US 20010048223A1
• Time in Patent Office: Days
• US Class Current: 285/21.1
• CPC Class Codes: B29C 65/342 comprising at least a single wire, e.g. in the form of a winding
• CPC Class Codes: B29C 65/344 being a woven or non-woven fabric or being a mesh
• CPC Class Codes: B29C 65/3444 being a ribbon, band or strip
• CPC Class Codes: B29C 65/3452 forming a sleeve, e.g. a wrap-around sleeve
• CPC Class Codes: B29C 65/3468 characterised by the means for supplying heat to said heated elements which remain in the join, e.g. special electrical connectors of windings B29C65/3668 takes precedence
• CPC Class Codes: B29C 65/348 with a polymer coating
• CPC Class Codes: B29C 65/4815 Hot melt adhesives, e.g. thermoplastic adhesives
• CPC Class Codes: B29C 65/5057 positioned between the surfaces to be joined B29C65/5035 takes precedence
• CPC Class Codes: B29C 66/1122 Single lap to lap joints, i.e. overlap joints B29C66/45, B29C66/472, B29C66/52272 take precedence
• CPC Class Codes: B29C 66/1142 Single butt to butt joints
• CPC Class Codes: B29C 66/1224 comprising at least a butt joint-segment
• CPC Class Codes: B29C 66/1226 comprising at least one bevelled joint-segment
• CPC Class Codes: B29C 66/1282 comprising at least one overlap joint-segment
• CPC Class Codes: B29C 66/12841 comprising at least two butt joint-segments
• CPC Class Codes: B29C 66/14 the joint having the same thickness as the thickness of the parts to be joined B29C66/1142 takes precedence
• CPC Class Codes: B29C 66/5221 for forming coaxial connections, i.e. the tubular articles to be joined forming a zero angle relative to each other
• CPC Class Codes: B29C 66/5229 involving the use of a socket
• CPC Class Codes: B29C 66/72523 multi-channelled or multi-tubular B29C66/438, B29C66/5227 take precedence
• CPC Class Codes: B29L 2023/22 Tubes or pipes, i.e. rigid bent tubes not for use as pipe couplings B29L2023/004
• CPC Class Codes: B29L 2024/00 Articles with hollow walls

Abstract

An improved coupler and method for fusing profile wall thermoplastic pipe in a manner to form a substantially flush joint are disclosed. The improved coupler is preferably configured to be inserted between the inner and outer walls of each of the pipes being joined. The improved coupler preferably has a radial thickness that is less than the radial dimension of the gap or channel that is formed between the inner and outer walls of the pipes being joined and is preferably configured and adapted to have an annular interference fit with one of either the inner or outer walls of such pipe ends. Electrofusion is preferably used to heat-fuse the improved coupler to each of the pipes to create a strong, leak-proof joint between the two pipes.

Claims

1. A joint comprising:

a pair of thermoplastic pipes, each of the pipes having an end margin terminating at a pipe end, the end margin of each of the pipes having radially spaced annular first and second walls separated by a void, the first wall of each of the pipes being one of inner and outer walls, the second wall of each of the pipes being the other of the inner and outer walls; and

an annular coupler having axially opposite end portions, one of the axial end portions of the coupler being positioned between the inner and outer walls of one of the pipes and the other of the axial end portions of the coupler being positioned between the inner and outer walls of the other of the pipes, the coupler engaging the first walls of the pipes via an annular interference fit, the coupler being at least partially formed of thermoplastic material and at least one of the axial end portions of the coupler being heat-fused to the end margin of at least one of the pipes.

2. The joint of

claim 1

, wherein the coupler is dimensioned such that each of the axial end portions of the coupler is radially spaced from the second wall of the respective pipe.

3. The joint of

claim 2

, wherein the first wall of each of the pipes is the inner wall of the respective pipe and the second wall of each of the pipes is the outer wall of the respective pipe.

4. The joint of

claim 1

, wherein the coupler has an annular groove formed therein, the joint further comprising an electrical resistance heating element positioned at least partially in the groove of the coupler, at least one of the axial end portions of the coupler being heat-fused to the end margin of at least one of the pipes via the electrical resistance heating element.

5. The joint of

claim 4

, wherein the annular groove of the coupler is arcuate in axial cross-sectional shape and the electrical resistance heating element is a rope-shaped thermoplastic encased wire.

6. The joint of

claim 5

, wherein the groove winds circumferentially into one of the axial end portions of the coupler and overlaps itself in an immediately adjacent manner, the groove extending to the other of the axial end portions of the coupler where the groove winds circumferentially into the other of the axial end portions of the coupler and overlaps itself in an immediately adjacent manner, the electrical resistance heating element being the sole electrical resistance heating element of the joint and the end margin of each of the pipes being fused to the coupler via the electrical resistance element.

7. The joint of

claim 1

, wherein each of the axial end portions of the coupler tapers radially in a manner such that the first walls of the pipes are radially deflected as a result of the engagement of the coupler therewith.

8. The joint of

claim 1

, wherein the coupler is heat-fused directly to the first walls of the pipes.

9. The joint of

claim 1

, wherein the coupler is heat-fused to the end margins of the pipes circumferentially about the coupler to provide an annular seal between the coupler and the end margins.

10. A joint comprising:

a pair of thermoplastic pipes, each of the pipes having an end margin terminating at a pipe end, the end margin of each of the pipes having radially spaced annular first and second walls separated by a void, the first wall of each of the pipes being one of inner and outer walls, the second wall of each of the pipes being the other of the inner and outer walls; and

an annular coupler having axially opposite end portions, one of the axial end portions of the coupler being positioned circumjacent the first wall of one of the pipes and the other of the axial end portions of the coupler being positioned circumjacent the first wall of the other of the pipes, the coupler engaging the first walls of the pipes via an interference fit in a manner such that the first wall of the end margin of each of the pipes radially deflects toward the second wall of the end margin of the respective pipe, the radial deflection being greatest at the end of the respective pipe and decreasing with distance from the end of the respective pipe, the coupler being at least partially formed of thermoplastic material and at least one of the axial end portions of the coupler being heat-fused to the end margin of at least one of the pipes.

11. The joint of

claim 10

, wherein the first wall of each of the pipes is the outer wall of the respective pipe and the second wall of each of the pipes is the inner wall of the respective pipe.

12. A method of joining thermoplastic pipes, the method comprising:

providing a pair of thermoplastic pipes, each of the pipes having an end margin terminating at a pipe end, the end margin of each of the pipes having radially spaced annular first and second walls separated by a void, the first wall of each of the pipes being one of inner and outer walls, the second wall of each of the pipes being the other of the inner and outer walls;

providing an annular coupler having axially opposite end portions, the coupler being dimensioned in a manner such that one of the axial end portions is positionable between the inner and outer walls of one of the pipes and such that the other of the axial end portions is positionable between the inner and outer walls of the other of the pipes, the coupler also being dimensioned in a manner such that the coupler engages with the first wall of the end margin of each of the pipes in an annular interference fit with the first wall of the end margin of each of the pipes being radially deflected when one of the axial end portions of the coupler is positioned between the inner and outer walls of the respective pipe, the coupler having at least one electrical resistance heating element attached thereto for providing heat to fuse at least one of the axial end portions of the coupler to the end margin of at least one of the pipes when the at least one axial end portion of the coupler is positioned between the inner and outer walls of the respective pipe;

inserting one of the axial end portions of the coupler between the inner and outer walls of the end margin of one of the pipes and the other of the axial end portions of the coupler between the inner and outer walls of the end of the other of the pipes, the coupler radially deflecting the first wall of the end margin of each of the pipes; and

passing an electrical current through the at least one electrical resistance heating element to heat-fuse the coupler to the end margin of each of the pipes in a manner such that the coupler operatively permanently connects the pipes together.

13. The method of

claim 12

, wherein the step of providing a coupler comprises providing the coupler with a dimension such that each of the axial end portions of the coupler will be radially spaced from the second wall of the respective pipe when the respective axial end portion of the coupler is inserted between the inner and outer walls of the respective pipe.

14. The method of

claim 13

, wherein the first wall of each of the pipes is the inner wall of the respective pipe and the second wall of each of the pipes is the outer wall of the respective pipe.

15. The method of

claim 14

, wherein the step of providing a coupler comprises providing the coupler with an annular groove formed therein, the at least one electrical resistance heating element of the coupler being substantially positioned within the groove of the coupler.

16. The method of

claim 15

, wherein the annular groove of the coupler is arcuate in axial cross-sectional shape, the at least one electrical resistance heating element of the coupler being at least one rope-shaped, thermoplastic encased wire that is at least partially positioned within the groove of the coupler.

17. The method of

claim 16

, wherein the annular groove of the coupler winds annularly into one of the axial end portions of the coupler and overlaps itself in an immediately adjacent manner, the groove extending to the other of the axial end portions of the coupler where the groove winds annularly into the other of the axial end portions of the coupler and overlaps itself in an immediately adjacent manner.

18. The method of

claim 12

, wherein the step of providing a coupler comprises dimensioning each of the axial end portions of the coupler such that each of the axial end portions of the coupler tapers in radial dimension in a manner such that the radial deflection of the first wall of the end margin of each of the pipes is greatest at the respective pipe end and decreases with distance from the respective pipe end when the axial end portion of the coupler is inserted between the inner and outer walls of the respective pipe.

19. The method of

claim 12

, wherein the step of providing a coupler comprises providing the coupler with solely one electrical resistance heating element and wherein the step of passing the electrical current through the electrical resistance heating element fuses the coupler directly to the first wall of the end margin of each of the pipes.

20. The method of

claim 12

, wherein the pair of thermoplastic pipes provided are helical-rib profile wall thermoplastic pipes, the end margin of each of the pipes having at least a portion of helical rib removed to form the void between the inner and outer walls of the end margin of each of the pipes.

21. The method of

claim 12

, wherein the pair of thermoplastic pipes provided are corrugated profile wall thermoplastic pipes.