Various methods of heating are required in the analytical laboratory ranging some of them are already discussed in the previous topics
Immersion Heater:
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 conc. 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
Heating Mantles:
The mantle may be supported in an aluminum case which stands on the bench, but for the use which 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 adjected.
The heating mantle is particularly designed for the heating of flasks and find wide applications in distillation operations. For details of the distillation procedure and description of the apparatus employed.
Crucibles and Beaker tongs:
Apparatus such as crucible, evaporating basins, and beakers which have been heated need to be headled with suitable tongs. Crucible tongs should be made of solid nickel, nickel steel, or other rustless ferro-arroy. For handling hot platinum or dishes, platinum-tipped tongs must be used. Beaker tongs are available for handling beakers of 100-2000 ml capacity. The tongs have jaws: an adjustable screw with locknut limits the span of these jaws and enables the user to adjust them to suit the container size.
