Flexible heating elements

The fibers are naturally drawn during the production process. The LS and HS fibers serve as filter mediums, catalyst carriers, and reinforcing fibers in composites. They have excellent ablation properties. Their relatively low electrical resistance has led to their use in flexible heating elements and wherever a bendable, nonme-tallic conductor is required. 

Electronic conductivity Flexible conductor of electricity heating elements (resistance heating), shielding of electromagnetic radiation field flattening (high-voltage cables), materials with antistatic capability... 

Heating mantles. These consist of a flexible knitted fibre glass sheath which fits snugly around a flask and contains an electrical heating element which operates at black heat. The mantle may be supported in an aluminium case which stands on the bench, but for use with suspended vessels the mantle is supplied without a case. Electric power is supplied to the heating element through a control unit which may be either a continuously variable transformer or a thyristor controller, and so the operating temperature of the mantle can be smoothly adjusted... 

Clamp-on band heaters, for use up to 700°C, are specified when high-watt densities are required or the external vessel area is limited. Heating elements can be woven into a quartz fabric to permit flexibility and ease of removal. These heaters are typically specified for lower-temperature demands because of their lower watt density. More rigid heater designs employ fully exposed, radiant heating elements or heating elements embedded within a ceramic fiber matrix. The latter are the heater of choice for high-temperature applications. 

It is important to note that the thermal-cycling rate is limited by the thermal mass of the heating element itself and of the entire micro-PCR device as well. Moreover, in the case of an external contact element, localized heating is ultimately limited in terms of lateral resolution by the thermal conductivity of the substrate material. In the case of on-chip integrated heaters, these devices still require tedious and complicated micromanufacturing processes, which restrict the flexibility to reconfigure the PCR design [133]. 

Tubular heating elements are extremely durable, resistant to contamination, and quite economical. They can be used on dies, radiant, thermoforming, and hot runner manifold applications. Tubular heaters provide temperatures up to 649°C and offer tremendous design flexibility. 

Another example where this technique is applied is FabRoc yam. EX02 (2014) manufactures electrically heated gloves for the ski and motorcycle markets that incorporate the yam. FabRoc is both flexible and electrically conducting and is formed into heating elements using the Thermoknit technology. 

In order to achieve sufficient stability against the cavity pressure and optimum heat dissipation, the sealing element A 4200 (MurSeal ) must be embedded into mold inserts made from mold steel. The attachment of the flexible sealing elements can be done by screwing, clamping, or by a frictional connection using locking pins. 

The Ohio State University (OSU) release rate apparatus consists of a chamber 35 X16 X 8 in., with a top section shaped like a pyramid connected to an outlet. The chamber contains an electrically heated radiant panel, a gas-fired radiant panel, or electrically heated elements. This test offers the flexibility of orienting the specimen either vertically or horizontally to simulate wall and floor applications (13). A photocell and a light source positioned above the outlet measures the light absorption. 

Pressure of the heating elements is also important and, whilst this again depends upon the material type and thickness, it is imperative in all cases that the pressure be equalised over the heating area. Therefore, the elements which, of course, are mounted onto a non-conductive material, should be rigidly fixed on a flat machined surface, or be completely flexibly mounted on a suitable rubber so that under pressure it finds its own level . 

To a hmrted extent, atomic absorption spectrometry can also be used for multielement determinations. Several manufacturers introduced systems with multilamp turrets, where different lamps can be held under pre-heated conditions. Here, rapid switching from one lamp to another enables sequential multi-element determinations to be made by flame atomic absorption, for a maximum of around five elements. Simultaneous determinations are possible with multi-element lamps, however, the number of elements that can be brought together and used as a hollow cathode lamp with a sufficiently stable radiation output and lifetime is rather limited. The use of continuous sources facilitates flexible multi-element determinations for many elements in principle. It is necessary to use high-resolution spectrometers (e.g., echelle spectrometers) with multi-channel detection. CCDs of-... 

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