| 摘要 |
<p>502,306. Asymmetrically-conducting resistances coating compositions. TRIGGS, W. W. (Mallory & Co., Inc., P. R.) June 3, 1938, No. 16652. [Class 37] [Also in Group III] A dry electric rectifier comprises a number of rectifier discs such as of copper sulphide 10 and magnesium 11, each pair being separated by a disc 12 as of carbonized nickel, pure iron or nickel-plated steel, a solid adherent insulating sealing layer being applied as a covering for all the edges, interior and exterior, to exclude air. The insulator may be applied to the clamped assembly before the end washers and nut are put on, but preferably it is introduced through slots 21 in the end washers. In a modification, the central bolt 18 is replaced by a hollow perforated tube through which the sealing insulator can be forced after assembly. A suitable compound comprises an air-blown petroleum asphalt, raw tung oil and manganese resinate cooked together and mixed with petroleum naphtha during cooling. Specifications 270,362, 272,568, [both in Class 38 (ii)], and 421,136 are referred to.</p> |
