摘要:
A photopolymerisable system is disclosed which can be polymerised by exposure to UV light, for example, to form a solid, light-transmitting sheet material having volume refractive index variations defining an optical diffuser or a hologram, for example. The system includes a silicone monomer, prepolymer, macromonomer or co-monomer capable of undergoing free radical initiated polymerization and further includes a photoinitiator.
摘要:
A fibre optic cable is helically wound on to an overhead high voltage conductor, and has an electrically non-tracking outer jacket and is filled with protective material, or has a conductive outer jacket. The cable is guided off the conductor inside a conductive housing, and then to earth potential along the inside of a non-tracking shedded or convoluted tube.
摘要:
The invention is a wire-stripping arrangement having recoverable material preferably in the form of heat-recoverable metal which is arranged to be capable upon recovery of cutting into the wire insulation and then to strip the insulation.
摘要:
A heat-recoverable article comprises a memory metal member to which has been imparted both thermally-recoverable and resiliently-recoverable strain. The resilient strain is retained by means of a disburdenable keeper, preferably one made from fusible or chemically degradable material, which can be removed, for example, by heating or chemical treatment, to allow resilient recovery. The article is preferably so constructed that it can be heated to obtain both thermal and resilient recovery simultaneously. One preferred form of article is a radially expanded longitudinally split tube, the keeper being positioned in the split. Such an article can be used as a connector to secure an earth lead to the sheath of a mineral-insulated cable.
摘要:
A hollow structure for use as an electrical insulator or other similar structure having outwardly disposed flanges extending circumferentially thereabout. The hollow structure includes a hollow member of heat recoverable material positionable about a central insulator core, electrical conduit, fuse or other substrate. The outwardly extending flanges are integrally formed with the hollow member and extend radially therefrom in the dimensionally heat stable state. The hollow member is designed to be expanded to a heat recoverable state for later facile positioning about an appropriate substrate. The hollow member may then be heat recovered about the substrate to become securely positioned thereon. Proper selection of the hollow member as to its dimensionally heat stable inner diameter relative to the inner diameter of the substrate results in control of the orientation of the flanges once the hollow structure has been recovered about the substrate.
摘要:
Netting formed of longitudinal and transverse threads of thermoplastic material bonded at the thread crossings by individual moulded buttons of thermoplastic material is improved by the use of threads that have been subjected to irradiation to cross-link their thermoplastic material. Higher moulding temperatures can be used in the formation of the bonding buttons, for example in the case of polyethylene filaments up to 260.degree. C or more, and increased bond strength between the crossing threads is achieved. The moulded buttons can also be formed of irradiated material.
摘要:
The invention provides a high voltage capacitor suitable for measuring the voltage of an overhead power line. The capacitor dielectric is mounted directly on to the power line conductor, which serves as one electrode of the capacitor. The other electrode of the capacitor is mounted on to the outer surface of the dielectric, and is protected at each side by a guard ring. Stress control is provided between the outer capacitor electrode and the guard rings and also at the outer edges of the guard rings. The capacitor may be enclosed in an earthed housing, which can contain one or more current transformers. The apparatus can be used for fault detection and location, and may be used in combination with a power cable or a switch.
摘要:
An enclosure for a shielded cable termination or joint comprises a protective sleeve comprising a conductive outer layer (51), an insulating inner layer (52), advantageously of substantially uniform cross-section for at least a portion of its length, and optionally a stress grading innermost layer (53). At least the insulating layer (52) and/or the stress grading layer (53) overlaps the or each cable shield, in the case of the insulating layer by an amount at least equal to the thickness of the portion of the insulating layer overlapping the cable shield end. Preferably the sleeve is installed by heat recovery.
摘要:
The invention provides an electrical insulator comprising a cylindrical core (2) of an insulating refractory material, such as porcelain, onto a portion of the curved surface of which a sleeve (8) of insulating polymeric material is fitted. Metal end-caps (4), for electrically connecting the insulator, are fitted to the ends of the porcelain core such that there is an exposed portion (10) of the curved surface of the core between the sleeve and each end-cap. Thus, any damaging electrical activity which takes place at the metal end-caps is directed primarily onto the surface of the porcelain core (2), and not onto the surface of the electrically vulnerable polymeric sleeve (8), which serves to protect mechanically the relatively brittle porcelain core. Optionally, the polymeric sleeve (8) may have a convoluted or a shedded outer surface (12) to increase the leakage path length of the insulator, or to prevent the formation of a continuous moisture path, or both.
摘要:
The substantial change in modulus with temperature of certain materials, especially memory metals, is used to make a novel connector by forcing a band made from such a material in its low modulus state up an external tapered portion of a tubular coupling member so as to deform the band which remains in position about the coupling member. To make a connection one or more substrates is (are) positioned inside the tubular coupling member and the band is brought to its high modulus state whereupon it contracts and deforms the tubular coupling member and forces it into firm connection with the substrate.