Article and method for sealing fluid-containing cables

• US 7,635,813 B2
• Filed: 09/10/2007
• Issued: 12/22/2009
• Est. Priority Date: 09/10/2007
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Brandyopadhyay, Pradip K., Taylor, William L., Evoniuk, Christopher J., Garcia-Ramirez, Rafael
• Primary Examiner(s): Nguyen; Chau N
• Application Number:
  US11/852,500
• Publication Number:
  US 20090065236A1
• Time in Patent Office: 834 Days
• Field of Search: 174/74.R, 174/93, 174/DIG.8
• US Class Current: 174/74.00R
• CPC Class Codes: H02G 15/1833 formed of helically wound strip with adjacent windings, which are removable by applying a pulling force to a strip end
• CPC Class Codes: H02G 15/24 Cable junctions

Abstract

A cable has a conductor extending therefrom and a partially exposed fluid-containing layer surrounding the conductor. A connector is joined to an end of the conductor, and an electrically insulative, elastomeric tube is covers all of the exposed fluid-containing layer and a portion of the connector. The elastomeric tube is substantially impermeable to the fluid in the cable. For cables having more than one conductor, an additional elastomeric boot is installed over the cable.

Claims

1. A cold-shrink seal for a cable having a plurality of conductors extending therefrom, and each of the plurality of conductors has a corresponding oil-containing layer surrounding the conductor, the cable end seal further comprising:

a plurality of cold shrink, electrically insulative, substantially oil-impermeable, elastomeric tubes, each elastomeric tube in tight conformity around an exposed portion of a corresponding one of the oil-containing layers, each elastomeric tube imparting resilient pressure to each oil-containing layer, wherein each elastomeric tube comprises a fluoroelastomer or a blend of fluoroelastomer and epichlorohydrin; and

a cold shrink, electrically insulative elastomeric boot around the plurality of conductors, the boot having a glove-like body including a single opening at a first end of the body and a plurality of openings at a second end of the body, the plurality of openings corresponding in number to the plurality of cable conductors, the boot applied to the cable such that each one of the cable conductors and its corresponding elastomeric tube exits the boot through a corresponding one of the multiple openings, the elastomeric boot imparting pressure to a portion of each one of the elastomeric tubes and oil-containing layer.

2. The cold-shrink seal of claim 1 wherein the elastomeric boot comprises a composition comprising a fluoroelastomer or a blend of a fluoroelastomer and an epichlorohydrin.

3. The cold-shrink seal of claim 2, wherein the elastomeric boot comprises in the range of about 10 parts to about 60 parts of fluoroelastomer per 100 total parts of fluoroelastomer and epichlorohydrin, and wherein the elastomeric boot comprises in the range of about 40 parts to about 90 parts epichlorohydrin per 100 total parts of fluoroelastomer and epichlorohydrin.

4. The cold-shrink seal of claim 1, wherein the elastomeric tube comprises in the range of about 10 parts to about 60 parts of fluoroelastomer per 100 total parts of fluoroelastomer and epichlorohydrin, and wherein the elastomeric tube comprises in the range of about 40 parts to about 90 parts epichlorohydrin per 100 total parts of fluoroelastomer and epichlorohydrin.

5. The cold-shrink seal of claim 1, wherein the elastomeric tube further comprises a filler material selected from the group consisting of reinforcement-grade carbon blacks, silica-based fillers, clays, fluoroplastics, metal oxides, and combinations thereof.

6. The cold-shrink seal of claim 1, wherein the cable comprises a PILC cable.

7. The cold-shrink seal of claim 1, wherein the elastomeric tube and boot are configured to elastically deform with expansion and contraction of oil in the oil-containing layer and provide relief of internal pressure in the cable.

8. A cold-shrink seal at a terminal end of a cable, the cable having a plurality of partially exposed central conductors, each conductor having a partially exposed, oil-impregnated, electrically insulative paper layer surrounding the conductor, a partially exposed semiconducting layer surrounding the paper layer, and a lead jacket surrounding the semiconducting layer, the cold-shrink seal comprising:

a cold-shrink, electrically insulative, substantially oil-impermeable elastomeric tube in tight conformity around the exposed portions of the semiconducting and paper layers of each conductor, the elastomeric tube comprising a composition of a fluoroelastomer or a blend of a fluoroelastomer and an epichlorohydrin; and

a cold-shrink electrically insulative elastomeric boot around a portion of each elastomeric tube, the boot having a glove-like body including a single opening at a first end of the body and a plurality of openings at a second end of the body, the plurality of openings corresponding in number to the plurality of conductors, the boot applied to the cable such each one of the conductors and its corresponding elastomeric tube exits the boot through a corresponding one of the multiple openings, the elastomeric boot imparting resilient pressure to a portion of each one of the elastomeric tubes and oil-containing layer therein.

9. The cold-shrink seal of claim 8, wherein the elastomeric boot comprises a composition of a fluoroelastomer or a blend of a fluoroelastomer and an epichlorohydrin.

10. The cold-shrink seal of claim 9, wherein the elastomeric tube and the elastomeric boot comprise in the range of about 10 parts to about 60 parts of fluoroelastomer per 100 total parts of fluoroelastomer and epichlorohydrin, and wherein the elastomeric tube and the elastomeric boot comprise in the range of about 40 parts to about 90 parts epichlorohydrin per 100 total parts of fluoroelastomer and epichlorohydrin.

11. The cold-shrink seal of claim 8, wherein the elastomeric tube has a length that is substantially equal to or greater than the combined lengths of the exposed portions of the semiconducting and paper layers.

12. The cold-shrink seal of claim 11, wherein the elastomeric boot has a length that is substantially equal to or greater than the length of the elastomeric tube.

13. The cold-shrink seal of claim 8 wherein the elastomeric boot further surrounds a portion of the lead jacket and a portion of the central conductor.

14. A method of providing an oil-stop at a terminal end of an electrical cable having a plurality of conductors extending therefrom, and each of the plurality of conductors has a corresponding oil-containing layer surrounding the conductor, the method further comprising:

for each one of the plurality of conductors and corresponding oil-containing layers,

removing a portion of the jacket, thereby exposing a portion of the oil-containing layer;

removing a portion of the oil-containing layer, thereby exposing a portion of the central conductor; and

placing a cold-shrink, electrically insulative, substantially oil-impermeable, elastomeric tube in tight conformity around a portion of the exposed portion of the oil-containing layer, the elastomeric tube imparting resilient pressure to the oil-containing layer, wherein the elastomeric tube comprises a composition comprising a fluoroelastomer and an epichlorohydrin; and

installing a cold-shrink, electrically insulative, elastomeric boot around the plurality of conductors, the boot having a glove-like body including a single opening at a first end of the body and a plurality of openings at a second end of the body, the plurality of openings corresponding in number to the plurality of conductors, the boot applied to the cable such each one of the conductors and its corresponding elastomeric tube exits the boot through a corresponding one of the multiple openings, the elastomeric boot imparting resilient pressure to a portion of each one of the elastomeric tubes and oil-containing layer therein.

15. The method of claim 14, wherein imparting resilient pressure to the oil-containing layer provides relief of internal pressure in the cable.

16. The method of claim 14, wherein installing the boot comprises overlapping the jacket and the central conductor.

17. The method of claim 14, wherein imparting resilient pressure to the oil-containing layers provides relief of internal pressure in the cable.

18. A cable transition joint comprising:

a cable having a plurality of conductors extending therefrom and a partially exposed oil-containing layer surrounding each conductor;

a connector joined to a terminal end of each conductor; and

for each of the plurality of conductors, a cold shrink, electrically insulative, substantially oil-impermeable, elastomeric tube in tight conformity around a portion of the exposed oil-containing layer and a portion of the connector, the elastomeric tube comprising a composition of a fluoroelastomer or a blend of a fluoroelastomer and an epichlorohydrin; and

a cold-shrink electrically insulative elastomeric boot around a portion of each elastomeric tube, the boot having a glove-like body including a single opening at a first end of the body and a plurality of openings at a second end of the body, the plurality of openings corresponding in number to the plurality of conductors, the boot applied to the cable such each one of the conductors and its corresponding elastomeric tube exits the boot through a corresponding one of the multiple openings, the elastomeric boot imparting resilient pressure to a portion of each one of the elastomeric tubes and oil-containing layer therein.

19. The cable transition joint of claim 18, wherein the elastomeric tube comprises in the range of about 10 parts to about 60 parts of fluoroelastomer per 100 total parts of fluoroelastomer and epichlorohydrin, and wherein the elastomeric tube comprises in the range of about 40 parts to about 90 parts epichlorohydrin per 100 total parts of fluoroelastomer and epichlorohydrin.