ELEKTRISK UPPVERMNINGSANORDNING FOR SNABB UPPHETTNING AV STROMMANDE MEDIER

摘要

An electric heating device for heating fluid media includes a plurality of disc-shaped porous bodies each consisting of a plurality of felted togehter polycrystaline metal whiskers grown out of a gas phase and connected each to one another at their points of contact. A plurality of disc-shaped electric heating elements alternate with the bodies to form a column for connection to a voltage source. The total electrical resistance of the elements is greater than the total electrical resistance of the porous bodies. In one embodiment the bodies and elements are both porous and form a longitudinal passage along the column and means are provided for delivering fluid medium to one end of the passage to be heated as it flows lengthwise of the column. In another arrangement the bodies and elements are centrally apertured to form a central longitudinal passage and means are provided for delivering the fluid medium to one end of the passage. In this arrangement the heating elements may be non-porous whereby the fluid medium flows radially through the porous bodies for heating. Alternatively, the heating elements may also be porous in which case fluid medium is heated as it flows radially through the elements as well as through the elements bodies.