Insulating multiple-conductor cables using coated insert means

• US 4,589,939 A
• Filed: 02/15/1985
• Issued: 05/20/1986
• Est. Priority Date: 02/17/1984
• Status: Expired due to Term

• Current Assignee: Tyco Electronics Corporation (TE Connectivity Ltd. (United Kingdom))
• Original Assignee: Raychem Limited (TE Connectivity Limited)
• Inventors: Toy, Lester T., Mohebban, Manoochehr, Versteegh, Willem M.
• Primary Examiner(s): Dawson, Robert A.
• Application Number:
  US06/702,117
• Time in Patent Office: 459 Days
• Field of Search: 156/49, 156/52, 156/55, 156/56, 156/86, 156/85, 156/91, 174/88 R, 174/102 R, 174/102 SC, 174/105 R, 174/106 SC, 174/113 R, 174/DIG. 8, 428/910, 428/913, 339/275 R, 339/275 C
• US Class Current: 156/49
• CPC Class Codes: H02G 15/08 Cable junctions for gas or oil filled cables H02G15/24
• CPC Class Codes: H02G 15/10 protected by boxes, e.g. by distribution, connection or junction boxes
• CPC Class Codes: H02G 15/18 protected by sleeves, e.g. for communication cable two-part covers H02G15/10 ; preforms having internal stresses B29C61/00
• CPC Class Codes: Y10S 174/08 Shrinkable tubes
• CPC Class Codes: Y10S 428/91 Product with molecular orientation
• CPC Class Codes: Y10S 428/913 Material designed to be responsive to temperature, light, moisture
• CPC Class Codes: Y10S 439/932 Heat shrink material
• CPC Class Codes: Y10S 439/933 Special insulation

Abstract

The conductors of multi-conductor, medium voltage, power cables, at locations where the cable insulation has been removed, are insulated by positioning between the conductors or cores, an insert, at least the surface of which comprises a first void-filling material capable of forming a substantially void-free interface with each conductor, placing a second void-filling material over the conductors and recovering a dimensionally recoverable polymeric sleeve over the resulting assembly. The method is particularly useful to provide insulation between conductors of a joint between two multi-conductor, medium voltage power cables.

Claims

1. A method of insulating the cores of a multiconductor, medium voltage power cable, at a location where the cable insulation is removed, said method comprising:

(a) selecting an insert shaped such that when it is positioned between the conductors of the cable it lies between each of the conductors, at least the surface of said insert comprising a first void-filling material capable of forming a void-free interface with each conductor;

(b) positioning the insert between the conductors such that it lies between each of the conductors;

(c) positioning a dimensionally recoverable polymeric sleeve over the resulting assembly; and

(d) causing the sleeve to recover.

2. A method in accordance with claim 1, which further comprises the step of positioning a second void-filling material around the conductors.

3. A method in accordance with claim 2, wherein the second void-filling material is positioned by placing the void filling material over the conductors in the form of shaped profiles.

4. A method in accordance with claim 1, wherein the dimensionally recoverable sleeve is heat shrinkable and the step of causing the sleeve to recover comprises applying heat to the sleeve.

5. A method in accordance with claim 4, wherein the heat shrinkable sleeve comprises an inner elastomeric layer and an outer conductive layer.

6. A method in accordance with claim 1, which further comprises applying a stress grading material to areas of high electrical stress.

7. A method in accordance with claim 1, which further comprises applying an initial insulating layer around each of the connectors and adjacent conductor regions.

8. A method in accordance with claim 7, in which the initial insulating layer is applied by positioning dimensionally recoverable sleeves over the connector and causing the sleeve to recover.

9. A method of insulating a joint between multiple-conductor, medium voltage power cables, each of said cables having at least three conductors each surrounded by a dielectric layer a portion of which has been removed to expose an end region of the conductor, the conductors of one cable being connected to the corresponding conductors of a second such cable, said method comprises:

(a) selecting an insert shaped such that when it is positioned between the conductors of the cables it lies between each of the conductors, at least the surface of said insert comprising a first void-filling material capable of forming a void-free interface with each conductor;

(b) positioning the insert between the conductors such that it lies between each of the conductors;

(c) positioning a dimensionally recoverable polymeric sleeve over the resulting assembly; and

(d) causing the sleeve to recover.

10. A method in accordance with claim 9, which further comprises the step of positioning a second void-filling material around the conductors.

11. A method in accordance with claim 10, wherein the second void-filling material is positioned by placing the void filling material over the conductors in the form of shaped profiles.

12. A method in accordance with claim 9, wherein the dimensionally recoverable sleeve is heat shrinkable and the step of causing the sleeve to recover comprises applying heat to the sleeve.

13. A method in accordance with claim 12, wherein the heat shrinkable sleeve comprises an inner elastomeric layer and an outer conductive layer.

14. A method in accordance with claim 9, which further comprises applying a stress grading material to areas of high electrical stress.

15. A method in accordance with claim 9, which further comprises applying an initial insulating layer around each of the connectors and adjacent conductor regions.

16. A method in accordance with claim 15, in which the initial insulating layer is applied by positioning dimensionally recoverable sleeves over the connector and causing the sleeve to recover.

17. A method in accordance with claim 9, which further comprises positioning a liner over the recovered sleeve.

18. A method in accordance with claim 17, which further comprises applying an outer protective jacket over the joint.