Raychem Limited

David Crofts

Martin A Wright

Stephen Hunter Diaz

Gabe Cherian

Anthony James Moore

David E Barnwell

Stephen Morris

John R Vinson

A circuit protection device for protecting electrical circuits against voltage transients comprises a chip package which includes a threshold switch device formed from an amorphous composition.

Circuit protection device

An arrangement for protecting an electrical circuit from a voltage transient having a fast rise time, e.g. in the order of 20 Vns.sup.-1 comprises a number of semiconductive threshold foldback switching elements preferably formed from a chalcogenide glass, in parallel with one another between the current carrying line of the circuit and earth. An additional, non-linear, circuit protection device is connected in parallel with the switching element between the current carrying line and earth, in order to pass high frequency components of the transient to earth.

Circuit protection arrangement

An arrangement for protecting an electrical circuit from a voltage transient having a fast rise time, e.g. in the order of 20 Vns.sup.-1 comprises a number of semiconductive threshold foldback switching elements, preferably formed from a chalcogenide glass, in parallel with one another between a current carrying line of the circuit and earth. One or more capacitors are connected in series with the switching elements between the current carrying line and earth in order to prevent any direct currents in the current carrying line holding the switching elements in their low resistance state.

A dimensionally recoverable polymeric article for enclosing at least part of an elongate object such as a cable or connector has a surface at least part of which has an electrically conductive layer, preferably a metal layer, adhering thereto to provide a screen against electromagnetic interference. The surface of the article carrying the layer is profiled in the form of a number of grooves that extend substantially perpendicularly to the direction of recovery of the article to allow the article to recover with substantially no change in dimension of the surface in the direction of recovery.

Dimensionally-recoverable article

An assembly for marking an elongate object, for example a wire or cable, comprises a flexible heat-recoverable marker strip (1) having one surface which is capable of receiving printed characters, and being supported on a rigid carrier strip to prevent premature recovery of the marker strip when heated, for example when heated to render the printed characters indelible. The assembly is characterized in that the other surface of the marker strip (1) is at least partly coated with a heat-activatable adhesive (2), and is provided with one or more areas of pressure-sensitive or contact adhesive (3) capable at least temporarily of securing the marker strip in position about the object after separation from the carrier strip, and preferably also capable of supporting the marker strip on the carrier strip before separation of the marker strip therefrom.

Assembly for marking elongate objects

A polymeric article, at least part of which is dimensionally-recoverable, preferably heat-recoverable, has, bonded to the surface of a dimensionally-recoverable portion thereof, a pliant, adhesive-receptive polymeric film which is soft at the temperature at which the dimensionally-recoverable portion is recovered, and which is substantially non-curable at ambient temperatures. The polymeric film is preferably based on a film-forming chlorinated resin or a film forming silane. The articles may be recovered over objects such as electrical equipment to provide electrical insulation and may be bonded to the object or other article with an adhesive without the necessity of any special surface treatment immediately before bonding.

A dimensionally-recoverable article which is particularly suitable for the manufacture or repair of cable harnesses has a dimensionally-recoverable portion formed from a material comprising a crosslinked segmented polyether-ester block copolymer and an adhesive portion comprising a polyether-ester random copolymer which portions are bonded together to form a single integral structure.

Dimensionally recoverable article with adhesive portion

A recoverable seal for sealing a container, especially an artillery ordinance cannister, comprising a heat-shrinkable continuous annular band having a uniform coat of heat-activatable adhesive on the inwardly-facing surface thereof which has a mean thickness of 0.01 to 1.0 mm and differs from the mean thickness over the surface by at most 25% of the mean thickness. The band may be provided with a tearable region such as a score line to enable it easily to be peeled off the container. After the band has been recovered on the container, the band can be peeled away and a layer of adhesive will remain aiding the ability of the seal to withstand pressurization and depressurization.

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Cirencester, United Kingdom

David Crofts