GB190713582A - Improvements in Electrical Resistances - Google Patents

Abstract

13,582. Jones, W. F. June 12. Resistances.-A tube 1 of iron or like metal is slit longitudinally at 2, and is coated with enamel, which fills up the slit, and then with a layer 4 of insulating-cement, on which the resistance wire 5 is wound in one or more layers, cement being placed between the layers. Flexible connecting-strips 6 are passed under the last few turns of wire at each end, the ends being bent over and secured by riveting or otherwise. More cement is placed over all, the whole being allowed to dry and then baked. The cement consists preferably of 75 parts of silica to 25 parts of sodium silicate, with sufficient water to make a paste. The complete resistance unit is glazed with an enamel, such as silicate enamel, extending over the ends of the core tube 1. The tube is mounted on its base by a bolt 11 passed through its centre and secured by nuts 12, which are provided with shoulders 13, or else screw against shouldered washers ; apertures 10 for ventilation are provided either in the ends of the tube or in the washers. According to the Provisional Specification, one nut may be omitted, the end of the tube being clamped against the base ; or the unit may be attached to its support by the flexible connecting-strips 6, suitable supports encircling the unit being provided.