GB848170A - Improvements in electric heating units and methods of making the same - Google Patents

Abstract

848,170. Electric heating resistors. GENERAL ELECTRIC CO. Sept. 24, 1958 [Oct. 18, 1957], No. 30497/58. Class 39(3). [Also in Group XXXVI] As a step in the manufacture of an electric heating unit bifilarly wound resistance conductors 12 and 13 are arranged within a metal sheath 11 and are commonly connected at one end of the sheath to an element 30 and at the other end to the legs 21 and 22 of a U-shaped element 20 (see Group XXXVI), the lower turns of the conductors being held in correct spaced-apart relationship by a cylindrical threaded refractory bushing 35 formed with a tongue which is inserted between the extreme outer ends of the legs 21 and 22. The sheath 11 is filled with finely divided magnesia and then rolled to reduce the crosssectional area and compact the magnesia into a dense mass 14; during this process the bushing 35 is crushed and forms part of the dense mass. The upper and lower ends of the sheath 11 are then cut off and plugs 18 and 19 are cast into the opposite ends of the sheath to seal it. The bight portion 23<SP>1</SP> of the element 20 is cut off and two distinct terminals 15 and 16 are thereby formed ; the upper end of the element 30 is cut off to produce a terminal 17. The heating unit thus formed may be used for the manufacture of heating elements for electric appliances, e.g. a cooking range.