| 摘要 |
615,560. Electric heating resistances. HADDAN, R. (Blue Ridge Glass Corporation). April 16, 1946, No. 11682. [Class 39 (iii)] A heating panel comprises a glass plate A having a conducting grid B deposited, thereon in bands, the peripheral bands b<3>, b<4>, b<5> and b<6> having a higher resistance per unit length than the inside bands b, so that more heat is generated at the margins of the plate and the tendency to cracking reduced. In the examples the peripheral bands are made narrower than the inside bands but other methods may be used e.g. varying their thickness or composition. The unicoated strips b<1> are bifurcated at their ends as at b<2> so that uniform resistance p.w.l. is maintained at the junctions of the bands b, or alternatively the strips b<1> may extend further towards the end of the grid as in Fig. 2 (not shown). Connection to the bands is by terminal C. The glass plate may be of tempered or heat-resistant glass, or armoured by wire embedded therein and it may be polished, ground, or sand-blasted and corrugated on one or both sides. |
