WIRE COVERING

Wire coating Wire, corded Wire covering Wire, electrical Wire enamel Wire insulation Wire materials Wire-rope machines Wires... 

The excellent electrical insulation properties of polyethylene have led to extensive use in cable and other wire-covering applications. Spectacular early uses included undersea cables and airborne radar and the materials continue to be used in substantial quantities. One particular trend is the increasing use of cross-linked polyethylene for this area of use. Such materials have improved heat resistance and in addition have given generally better resistance to stress cracking. Cellular polyethylene is used as the insulator for television downlead aerials. 

In spite of these problems the rubber continues to be widely used in mechanical goods, wire covering, auto applications and adhesives. 

Excellent toughness and wear resistance. For example, the resistance to cut through of wire coverings is far superior to that of most other heat-resisting plastics. It is interesting to note that in 1994, 50% of applications of PEEK were related to the excellent wear behaviour. 

Another major type of coating process is wire covering. The tremendous demand for insulated cables in the electrical industry means that large tonnages of plastic are used in this application. Basically a bare wire, which may be heated or have its surface primed, is drawn through a special die attached... 

Wire covering can be analysed in a very similar manner to that described for extrusion. The coating on the wire arises from two effects ... 

The condenser, attached to the flask by a ground-glass joint, is a Pyrex tube 50 cm. long and 20 mm. in internal diameter, wound with No. 26 Nichrome wire covered with asbestos paper. It is connected to a variable transformer and adjusted so as to maintain a temperature of 100-110°. A copper Liebig condenser heated by steam is also suitable provided that the inner tube has a diameter of about 20 mm. 

First find the two wires in the rocket tail section which disappear through a plastic plug into the rocket motor. (In the current model of the 3.5, these are the two wires covered with clear plastic.)... 

An extruder die-box or head in the shape of a letter T used in wire covering. The rubber flow is thus at right angles to the direction of travel of the wire. 

Molecules can lose an electron when subjected to a high electric potential resulting in field ionization (FI) [366,534,535]. High fields can be created in an ion source by applying a high voltage between a cathode and an anode called a field emitter. A field emitter consists of a wire covered with microscopic carbon dendrites, which greatly amplify the effective field at the carbon points. 

Japan Synthetic Paper has developed a PP foaming process. The non-crosslinked PP is continuously extruded to produce foamed sheeting and the sheet is further vacuum moulded by the conventional process. The foamed PP is recommended for thermal insulation of hot water pipes, air conditioning plumbing and wire coverings. 

Principal uses include automotive V-belts, industrial and hydraulic hose, specialty roofing, heels and soles in footwear, wire covering, and a wide variety of coated fabric uses, eg, rafts. Chloroprene elastomers are also used extensively in adhesives (qv). It is estimated that about 77,000 t of chloroprene are used each year in the United States. The two main suppliers of chloroprene elastomers in the United States are DuPont and Bayer. In addition, Distiguil (France) sells polymers through the A. Schulman Company. 

A typical electrode of this kind consists of a silver wire covered with a thin coating of silver chloride, which is insoluble in water. The electrode reaction consists in the oxidation and reduction of the silver ... 

The problem is most likely to occur when extrudates of small diameter are being made at high speed—as for example in wire covering. 

PVCA is a copolymer of vinyl chloride and vinyl acetate. It is a colorless thermoplastic solid with good resistance to water as well as concentrated acids and alkalis. It is obtainable in the form of granules, solutions, and emulsions. Compounded with plasticizers, it yields a flexible material superior to rubber in aging properties. It is widely used for cable and wire coverings, in chemical plants, and in protective garments. 

SOLUTION The surface and interface temperatures of a resistance wire covered with a ceramic layer are to be determined. 

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