The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 11, 1994
Filed:
Apr. 10, 1992
Josef Boes, Weilrod, DE;
Leo Saris, Nauheim, DE;
Kanthal GmbH, , DE;
Abstract
A vacuum-molded electrical radiant heating unit having a resistance heating coil embedded in a ceramic fiber body is prepared by a process in which a resistance heating coil (5) is placed on a sieve-like tray (1), above a suction box, and a slip is applied thereto composed of ceramic fibres, so that a ceramic fibre layer (4) builds up under the action of suction. Portions of the sieve-tray (1) are closed, in regions beneath the resistance heating coil (5) by means of spacing strips (11). These strips, which cover some of the perforations in the sieve-tray (1), are placed beneath the resistance-heating coil (5), in a manner such that the impervious regions of the sieve tray (1) are narrower than the width dimensions of the heating coil (5). These measures lead to the result that the space (8) inside the heating coil (5) remains free of fibre material during the vacuum-moulding operation, so that the temperature difference between the radiating side (6) of the heating coils (5) and the rear side (7), which lies within the composition forming the fibre block (4), is smaller than in conventional heating units of this type, in which there is a risk of crystallisation of the fibres forming the fibre block (4). The use of spacing strips (11) produces retaining webs (12) on the radiating side (9) of the fibre block (4), which ensure that the heating coils (5) are securely anchored.