Temperature resistance wire

Polyether imide n. A polymer containing both ester and imide groups in the polymer chain. They are usually synthesized by polycondensation between a dianhydride containing aromatic ester links and a diamine. Their main use is as high temperature resistant wire See image). 

Kanthal. High temperature resistance wire and tape for heaters (A.B. Kanthal, Sweden). 

Co, by weight, is an extremely powerful magnet that offers a B-H (max) almost twice that of Alnico V. Platinum resistance wires are used for constructing high-temperature electric furnaces. 

Cyanoacrylate adhesives (Super-Glues) are materials which rapidly polymerize at room temperature. The standard monomer for a cyanoacrylate adhesive is ethyl 2-cyanoacrylate [7085-85-0], which readily undergoes anionic polymerization. Very rapid cure of these materials has made them widely used in the electronics industry for speaker magnet mounting, as weU as for wire tacking and other apphcations requiring rapid assembly. Anionic polymerization of a cyanoacrylate adhesive is normally initiated by water. Therefore, atmospheric humidity or the surface moisture content must be at a certain level for polymerization to take place. These adhesives are not cross-linked as are the surface-activated acryhcs. Rather, the cyanoacrylate material is a thermoplastic, and thus, the adhesives typically have poor temperature resistance. 

Fig. 3. Pressure required for ignition of mixtures of acetylene and a diluent gas (air, oxygen, butane, propane, methane, carbon monoxide, ethylene, oil gas, nitrogen, helium, or hydrogen) at room temperature. Initiation fused resistance wire. Container A, 50 mm dia x 305 mm length (73) B,...

Temperature Dry wire-pipe ESPs can operate at very high temperatures, up to 700°C (1300°F). Operating gas temperature and chemical composition of the dust are key factors influencing dust resistivity and must be carefully considered in the design of an ESP. 

Insulation Since the insulation value drops sharply with temperature, the wire would be limited in service temperature to 140°F (60° C), where both of these materials soften. The additional wall thickness above the theoretical minimum is used to give some mechanical strength to the insulation as well as to improve the resistance to cut through and bending. Since each of the conductors can handle 600 volts, it is possible to use two of the wires to handle 1200 volts. This is usually not done because of the possibility of grounding one of the conductors that would expose the other one to the full field. 

Electric tube furnaces of appropriate dimensions are available from various manufacturers. A model RO 4/25 by Heraeus GmbH, Hanau, FRG is suitable. However, a very satisfactory furnace can be built by any well equipped laboratory workshop at little cost and effort. The material required consists of thin walled ceramic tubing, 3.5 cm i.d., nichrome resistance wire, heat resistant insulation, and ordinary hardware material. A technical drawing will be provided by the submitters upon request. The temperature of the furnace can be adjusted by an electronic temperature controller using a thermocouple sensor. A 1.5 kW-Variac transformer and any high temperature thermometer would do as well for the budget-minded chemist. 

Its high melting point also makes it useful for metal electrodes in glassmaking furnaces. Molybdenum s high resistance to electricity makes it useful in high-temperature filament wires and in the construction of parts for missiles, spacecrafts, and nuclear power generators. 

The resolution of potentiometric transducers is dependent upon the construction of the resistance element. In the case of a wire-wound resistance, in order to obtain a high resistance in a small space, the resistance wire is wound on to a mandrel or card which is straight or formed into a circle or helix depending upon the motion of the contact. This limits the resolution of the transducer as the wiper moves from one wire to the next on the mandrel. The best resolution that can be obtained is about 0.01 per cent (see Section 6.10.1). Typical wire-wound potentiometers have strokes of between 0.0025 m and 0.5 m and rotational versions from about 10° of arc to 50 turns. An alternative often employed is the conductive plastic film element. This provides a continuous resistance element and thus, a zero resolution, but such elements suffer from a higher temperature coefficient of resistance. A more recent development is a combination of earlier types in which a conductive plastic coating is sprayed on to a wire-wound resistor. 

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