GB499447A - Improvements in and relating to electric heating elements - Google Patents

Abstract

499,447. Couplings. NAAMLOOZE VENNOOTSCHAP MOLYBDENUM CO. March 11, 1938, Nos. 7656 and 7657. Convention dates, March 11, 1937 and Nov. 23, 1937. [Class 38 (i)] In order to make a sealed connection to a heating element 1 of molybdenum, tungsten, tantalum, &c. enclosed in a ceramic sheathing 2 so as to exclude atmospheric oxygen, the sheathing is prolonged beyond the end of the element 1 and a pin 3 of copper, silver, nickel, or an iron-nickel-cobalt alloy, &c. is fitted into the end of the sheathing, and fused or poured on to the end of the element 1 and a sleeve-like plug 4 drawn over the projecting part of the pin to close the sheath. The temperature of the pin may be so regulated in operation that it forms a plastic mass that by its expansion within the sheathing forms a seal, or the dimensions or materials of the pin may be such as to conduct away the heat sufficiently to allow solders or cements to be used to seal the end of the sheathing. The pin may be made up of sections 3<1>, 3<11>, 3<111>, Fig. 4, having increasing diameters or conductivity so that tin, lead, brass, or silver solders may be employed at the point 5 (the ceramic material having been metallized to ensure adhesion) or cements, such as silver chloride, lead oxide and glycerine, waterglass, or glass, or even organic cements such as artificial resins may be employed without their being heated beyond a semi-plastic state. The sleeve-like plug 4 attached to the pin forms the terminal.