Electricity: conductors and insulators – Conduits – cables or conductors – Combined
Patent
1992-05-04
1994-04-05
Picard, Leo P.
Electricity: conductors and insulators
Conduits, cables or conductors
Combined
174DIG8, 174DIG11, 138128, 138156, 138158, 138167, H02G 304, F16L 1100
Patent
active
053007328
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to the formation of an environmental seal, particularly around a cable splice or a pipe, especially in cramped conditions or otherwise where curvature of cables or pipes is to be expected.
There are many instances where it is desirable to provide an environmental seal in order to keep out contaminants such as water or to insulate electrically etc, particularly where an end of the cable or other substrate is not accessible or where it is undesirable to disconnect or otherwise displace such an end. Environmental seals for cables and pipes are frequently made by recovering (generally heat-shrinking) a dimensionally-recoverable sleeve around the cable or pipe. The sleeve is supplied over-size allowing it to be installed easily and without the need for close tolerances in manufacture, and is then shrunk generally by heating it with an open-flame torch, into sealing engagement. Many proposals have been made for ways of making such heat-shrinkable sleeves of so-called "wrap-around" design, allowing installation as mentioned above where an end of the substrate to be sealed is not accessible.
In general, a "wrap-around" sleeve is simply a sheet of material that can be installed around a substrate with no free ends and that has some means whereby it may be held in the wrapped configuration, particularly during heat-shrinkage.
The only commercially significant heat-shrinkable wrap-around sleeve is disclosed and claimed in GB1155470 (Raychem), which provides: along the length of the outer surface thereof the dimensional state of the tubular member having been changed from an original heat-stable form to a heat-unstable form, the ridge having a portion of reduced cross-section adjacent to the outer surface of the tubular member, the ridge and the member being longitudinally split, and having two portions facing each other, and fastening means for sliding over the ridge to retain the fastening portions in abutting relationship.
The disclosure of that patent and of other patents and applications mentioned below are incorporated herein by reference.
The closure of that patent has become known as the "rail-and-channel" closure. The terms "rail" and "channel" will be used below in the present specification where it is believed that their meaning will be clear. It is pointed out, nonetheless, that these terms imply no particular shape, and are not to be interpreted as requiring the shape illustrated or described in GB1155470.
Other designs of wrap-around sleeve may be briefly mentioned. EP 0034500 (Raychem) discloses a closure assembly comprising
a recoverable wrap-around sleeve, and
a longitudinal flexible elongate fastening member, wire-like or rod-like gripping portions arranged substantially parallel to, and laterally spaced from, each other with their lengths disposed substantially longitudinally relative to the fastening member, and connected to each other by each of at least three wire-like or rod-like connecting members, which lie substantially outside the plane containing the first and second gripping portions; the arrangement being such that the fastening member can grip between, and by mutual gripping action of, its first and second gripping portions one or more fastening portions of the sleeve to hold the sleeve closed during the recovery.
DE 2652617 (Raychem) disclosed a heat-recoverable wrap-around article which is made from sheet material and is adapted to recover snugly about a bend in a substrate to conform to said bend and thus substantially avoid the formation of undesired wrinkles, the article being provided with means to facilitate fastening it in position prior to recovery. The material is held closed by a rail-and-channel closure as illustrated in GB 1155470, but no explanation is given as to how the closure accommodates the curves.
Whilst those techniques, particularly that of GB 1155470, have proved useful there remains a problem in providing a cable splice closure around a highly curved splice, particularly where a cable is confined within a man-hole (which includes a h
REFERENCES:
patent: 3455336 (1969-07-01), Ellis
patent: 4498938 (1985-02-01), Moisson et al.
patent: 4499129 (1985-02-01), Kridl et al.
patent: 4761194 (1988-08-01), Pithouse et al.
patent: 4795509 (1989-01-01), De Bruycker
patent: 4860799 (1989-08-01), Van Noten
Nolf Jean-Marie E.
Wambeke Alain
Burkard Herbert G.
Picard Leo P.
Raychem Corporation
Sough Hyung S.
Zahrt II William D.
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