| 摘要 |
757,221. Electric heating panels. GENERAL ELECTRIC CO. Oct. 14, 1953 [Oct. 14, 1952], No. 28349/53. Class 39(3). An electric heating panel comprises front and back metal members 10, 11 gas-tight sealed around their edges to form a chamber 13, and a heating element 15 insulated from the member 10 by mica or cloth made of silicon dioxide fibres 14. A blanket 21 of aluminium oxide powder or fibre, high-melting slag wool, mica, or silicon dioxide granules or fibre, overlies the element 15, and thermal insulation 22 of glass fibre or slag wool occupies the space between the blanket 21 and the metal member 11, i.e. more than half the space between the members 10, 11. The insulation 22 may be formed as disclosed in Specification 715,175 (Groups XIII, XXIII) and Specification 715,174 (Groups XI, XIII), individual fibres thereof preferably having a diameter of less than one thousandth of an inch and being packed to a density in excess of ten pounds per cubic foot. The chamber 13 is preferably evacuated to a pressure of less than one millimetre of mercury, e.g. ten to one hundred microns, and during evacuation the panel is heated to drive off occluded gases of the materials within the panel. Carbon steel having a porcelain enamel finish or a coating of resin, corrosion resistant alloys and stainless steel are specified as materials for the members 10, 11. A modification, Fig. 2 (not shown), has a concertina form of side wall which is stated to reduce heat losses along the edges of the panel. Specification 342,684 also is referred to. |
