SU826571A2 - Submersible electric heater for aggressive media - Google Patents

Description

(54) SUBMERSIBLE ELECTRIC HEATER

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The invention relates to electrothermal and can be used in metallurgy, chemistry and mechanical engineering when heating highly corrosive and corrosive liquids and metals, for example zinc, aluminum.

According to the main author. St. No. 604197 is known for a movable electric heater containing a sheath of a material resistant to aggressive media, made along the length of two hermetically connected elements, the lower of which, fully buried in the medium, is made of highly thermally conductive material, for example, impregnated with graphite metallophate, and the upper, partially protruding from the environment, from the heat-insulating heat-resistant material, for example, cast potassium fluoroflogalite, a heating element and current conductors are installed inside the shell, one of which serves t grounding and sealing element 1.

The disadvantage of the design is the low efficiency of heat transfer from the heating element to the shell, which leads to thermal stress of the heating element and a decrease in its service life, due to the presence of an air gap between the shell and the sealing heat-conducting glass.

The purpose of the invention is to increase the service life of the electric heater.

This goal is achieved by the fact that on the inner surfaces of both shell elements there is an annular groove filled at the ends with a sealed cavity between the elements of the shell and the current cup supplying a sealed cavity filled with heat-conducting non-aggressive liquid with low vapor pressure, for example molten lead.

The drawing shows an immersion heater, a longitudinal section.

Claims (1)

Immersion heater comprises a contact graphite sleeve 1, conductive backfill 2, preservatives moiety of from oxidation graphite sleeve, the lower member 3 casings impregnated metallophosphates graphite electrical heating element 4, the upper foil member 5, a refractory sealing putty 6, the sealing currentcarrying conductive glass 7 sealing insulating sleeve 8 and terminals 9. On the inner surfaces of both elements 3 and 5 of the shell, the annular groove was plugged at the ends with the formation of a sealed cavity 10 between the elements 3 and 5 of the shell and glass ,. The cavity 10 is filled with a heat-conducting non-aggressive liquid with low vapor pressure, for example, molten lead. Submersible heater works as follows. When voltage is applied to the terminals 9, the electric current flows through the circuit: the grounding and sealing cup 7 - contact sleeve 1 - heating element 4. Due to the large ohmic resistance of the heating element 4, heat is generated, which is transferred to the heat transfer (radiation) the walls of the sealing cup 7, then through the cavity 10 filled with metal is transferred to the heat-conducting graphite sheath 3 and to the heated metal (in the liquid bath). Performing an immersion heater with a cavity between the inner surface of the cladding elements and a sealing glass filled with a thermally conductive non-corrosive liquid, such as molten lead, reduces the time just for replacing heaters, eliminating the cost of heating, and increases its service life. The invention of the submersible heater for corrosive media on author. St. No. 604197, characterized in that, in order to increase the service life, on the inner surfaces of both elements of the shell, an annular groove is plugged at the ends with the formation of a sealed cavity between the elements of the shell and the current-sealing inlet cup filled with heat-conducting non-aggressive liquid with low elasticity of vapor, for example molten lead. Sources of information taken into account in the examination 1. USSR author's certificate No. 604197, KL ..N 05 V 3/78, 1976.