Forced encapsulation means for a cable

• US 4,875,952 A
• Filed: 02/08/1988
• Issued: 10/24/1989
• Est. Priority Date: 06/11/1984
• Status: Expired due to Term

• Current Assignee: Fitel USA Corporation (Furukawa Electric Company Limited)
• Original Assignee: American Telephone & Telegraph Company (AT&T, Inc.)
• Inventors: Reed, William C., Mullin, Francis J.
• Primary Examiner(s): Dawson, Robert A.
• Application Number:
  US07/150,480
• Time in Patent Office: 624 Days
• Field of Search: 156/48, 156/49, 156/53, 156/56, 174/23 R, 174/76, 174/88 R, 174/92, 428/35.7, 428/36.91, 428/137, 428/304.4
• US Class Current: 156/48
• CPC Class Codes: H02G 15/003 Filling materials, e.g. solid or fluid insulation
• CPC Class Codes: H02G 15/10 protected by boxes, e.g. by distribution, connection or junction boxes
• CPC Class Codes: H02G 15/196 having lapped insulation
• CPC Class Codes: Y10T 428/1393 Multilayer [continuous layer]

Abstract

A forced encapsulation system and method that can be advantageously used to encapsulate cable splices e.g., multiconductor communications cables. Containment means are formed around a substrate comprising part of at least one cable, and secured to the cable, thereby forming an enclosure into which liquid encapsulant can be introduced under pressure and in which the encapsulant can be maintained at pressure above ambient pressure. In a preferred embodiment, the containment means comprise a containment bag formed in situ from an elastomer sheet and sealed to the cable sheaths, with a reinforcing outer enclosure surrounding the containment bag. Introducing the liquid encapsulant under pressure leads to thorough penetration of the encapsulant into the splice work and cable ends and to intimate contact between the cured encapsulant and the surfaces within the enclosure, including surfaces with which the encapsulant does not form an adhesive bond, resulting in improved gasketing around conductors, thereby reducing the possibility of water-caused splice damage.

Claims

1. Means for enclosing a portion of at least one cable, comprising

(a) expandable first means adapted for surrounding at least the portion of the cable and for being sealed to the cable, thereby forming containment means adapted for receiving therein, through encapsulant-introduction means, a quantity of liquid encapsulant of a type whose viscosity increases with time until the encapsulant is no longer a liquid at room temperature;

and

(b) substantially rigid outer enclosure means adapted for surrounding the containment means characterized in that

(c) the containment means are adapted for having the liquid encapsulant therein pressurized to a first pressure that is substantially greater than ambient pressure, and for maintaining the liquid encapsulant therein under a pressure above embient pressure for a time such that at least part of the encapsulant is no longer a liquid at room temperature;

(d) the outer enclosure means are adapted for substantially restraining expansion of the containment means with the pressurized liquid encapsulant therein; and

(e) the encapsulant-introduction means are of a type that permits further introduction of liquid encapsulant into the containment means after introduction and pressurization of the quantity of liquid encapsulant.

2. The means of claim 1, wherein the first pressure is at least about 1 psi above ambient pressure, and wherein the first means comprise an elastomer sheet, with part of the surface of the elastomer sheet carrying pressure-sensitive adhesive means.

3. The means of claim 1, adapted for enclosing part of each of at least two cables with a splice therebetween.

4. The means of claim 1, wherein the cable is a multiconductor communications cable.

5. The means of claim 4, wherein the cable is a telephone cable.

6. A method of enclosing a portion of at least one cable comprising

(a) forming expandable containment means around at least the portion of the cable, the containment means being secured to the cable and being adapted for receiving therein a liquid encapsulant;

(b) surrounding the containment means with substantially rigid outer enclosure means; and

(c) introducing a quantity of the liquid encapsulant into the containment means, the encapsulant being of a type whose viscosity increases with time until the encapsulant is no longer a liquid at room temperature;

characterized in that the method further comprises

(d) pressurizing the encapsulant in the containment means to a first pressurize that is greater than ambient pressure, with the outer enclosure substantially restraining expansion of the containment means, and maintaining the liquid encapsulant under a pressure above ambient pressure for a time such that at least a part of the quantity of encapsulant is no longer a liquid at room temperature; and

(e) introducing the liquid encapsulant into the containment means through encapsulant-introduction means that are of a type that permits further introduction of liquid encapsulant into the containment means after introduction and pressurization of the quantity of liquid encapsulant.

7. The method of claim 6, wherein the containment means are formed by a procedure that comprises wrapping an elastomer sheet around a part of each of at least two cables and a splice therebetween, fastening the sheet to itself such that a substantially tubular structure is formed, and securing the tubular structure to each of the two cables.

8. The method of claim 6, wherein the liquid encapsulant in the containment means is pressurized by pumping at least some of the liquid encapsulant into the containment means.

9. The method of claim 8, comprising pumping a further quantity of liquid encapsulant into the containment means after the pressure on the liquid encapsulant has decreased, whereby the pressure on the encapsulant in the enclosure means can be restored to substantially the first pressure.

10. In combination, a length of at least one cable and first means for enclosing a part of the length of cable, wherein the first means comprise

(a) expandable containment means surrounding at least the part of the cable and secured to the cable;

(b) substantially rigid outer enclosure means surrounding the containment means;

(c) encapsulant, of a type that forms from a liquid encapsulant, contained within the containment means;

characterized in that

(d) the containment means comprise encapsulant-introduction means adapted for introducing therethrough a first quantity of liquid encapsulant into the containment means, the containment means adapted for pressurization of the liquid encapsulant to a first pressure above ambient pressure, with the outer enclosure substantially restraining expansion of the containment means with the pressurized liquid encapsulant therein; and

(e) the encapsulant-introduction means are adapted for optional introduction of a further quantity of liquid encapsulant into the containment means after introduction and pressurization of the first quantity of liquid encapsulant.

11. The combination of claim 10 comprising at least two cables and a splice therebetween, wherein the containment means comprise an elastomer sheet, wrapped around a part of each of the two cables and the splice therebetween, fastened to itself and to each of the two cables;

wherein the outer enclosure means comprise a split shell and means for securing the split shell closed; and

wherein the encapsulant-introduction means comprise a spout that is attached to the containment means and extends through the split shell.