Infrared heater

Infrared lamps and heaters. Infrared lamps with internal reflectors are available commercially and are valuable for evaporating solutions. The lamp may be mounted immediately above the liquid to be heated the evaporation takes place rapidly, without spattering and also without creeping. Units are obtainable which permit the application of heat to both the top and bottom of a number of crucibles, dishes, etc., at the same time this assembly can char filter papers in the crucibles quite rapidly, and the filter paper does not catch fire. 

Infrared radiant heaters provide an increase in the efficiency of heat transfer, exceeding that of oven heaters. Infrared heaters are useful in rapid heating of localized areas of a substrate. However, the rate of heat transfer is dependent, to some extent, on the color of the workpiece. The darker the part, the more rapid the heating.19 Radiant heaters are also more expensive and maintenance-dependent than air circulating ovens. 

Heating Devices. The sample can be heated by resistance heaters, infrared or micro-wave radiation, or by heat transfer from hot liquids or gases. Resistance heaters are the most common. 

Having removed the larger droplets, it may remain only to encourage natural evaporation of solvent from the remaining small droplets by use of a desolvation chamber. In this chamber, the droplets are heated to temperatures up to about 150 C, often through use of infrared heaters. The extra heat causes rapid desolvation of the droplets, which frequently dry out completely to leave the analyte as small particles that are swept by the argon flow into the flame. 

The increase of restrictive regulations on the use of organic solvents favoured the increasing use of latex-based adhesives. Because of the slow evaporation of water, these adhesives show less tack and can suffer bacterial attack. Infrared heaters and ovens can be used to favour the evaporation of water. Often a small amount of solvent (coalescing aid) is added to the latex system to improve wetting and coalescence of the latex particles. 

Immersion heaters. An immersion heater consisting of a radiant heater encased in a silica sheath, is useful for the direct heating of most acids and other liquids (except hydrofluoric acid and concentrated caustic alkalis). Infrared radiation passes through the silica sheath with little absorption, so that a large proportion of heat is transferred to the liquid by radiation. The heater is almost unaffected by violent thermal shock due to the low coefficient of thermal expansion of the silica. 

In the simplest case the developed chromatograms are heated to the required temperature on a hot plate (Fig. 19) or in a drying cupboard. More rarely infrared heaters are used to heat the system [2]. Gas chromatograph ovens can be used if exact adjustment of the temperature is required [3]. 

Vulcanisation using hot air systems remains the most important production system for profile production. Hot air can be used alone but can also be supplemented by the addition of infrared heaters. The systems usually consist of modular units which can be built up into the required length. Air speed can usually be controlled and the compound throughput can be adjusted from speeds of 2.5 m/sec up to 20 m/sec. These systems are sufficient for thin section profiles, but thicker articles will require slower transport speeds. Addition of microwave systems to these units... 

Water on the plate surface is removed with the sponge rolls for removal of water, and the surface is dried with 90-100°C convectional air, and then further dried with 90-100°C far-infrared heater. 

Figure 3.3 Side- and top-view of the in situ infrared autoclave. A IR window B Turbine rotor C Reagent addition D Thermocouple E Opening between upper and lower chamber F Electrical heaters C Kalrez O-rings (from Ref [6], reproduced by permission of Elsevier).

Different devices are used to maintain the preset temperature in a mold cabinets, boilers, chambers, baths, infrared heaters, electromagnetic radiation, and so on. In a number of cases, solidification takes place owing to the heat output during the chemical reactions. 

The coated foil is then processed to the next step, the drying compartment. The drying compartment essentially consists of a convection heater with two small slits for the traversing of the foil. The surface temperature of the foil is measured by an infrared detector. Temperature control is crudal in this process step, as the aqueous slurry must not be allowed to boil, which would deteriorate the coat evenness. During drying, the coat thickness shrinks (depending on the water content of the... 

Basecoats are normally cured in heated ovens with high air velocity or with infrared heaters excessive panel temperatures should be avoided to prevent drying of the particleboard. A light scuff sanding of the basecoat is used to remove high spots, followed by a brush cleaning to remove the dust and debris. 

Subboiling distillation circumvents both of these problems and is considered a simple and effective technique for removing metallic or cationic impurities (Figure 7.2). In subboiling distillation, infrared heaters vaporize liquid from the surface without boiling. The vapor is condensed on a tapered cold finger, and the distillate is collected in a suitable container. 

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