Patent GB-250188-A (GB)
Title: Improvements in or relating to thermo-electric generators and the manufacture thereof
IPC: H01L35/00
Filed: 1926-02-18
Abstract: 250,188. British Thomson-Houston Co., Ltd., (Assignees of Adams, N. H., and Fuller, T. S.). March 31, 1925, CG'onvention date]. Thermo-electric batteries.-Comprises arrangements for concentrating heat upon the hot junctions of thermopiles, and for minimizing conduction of heat to and cooling the cold junctions, constructions of heating and cooling elements, and methods of assembling the leaves of the piles. The hot junctions are recessed, and the recessed ends of two piles 1, 2, Fig. 1, arranged to embrace the heater 39. The region of the piles just behind the hot junctions is reduced to a narrow neck 3 to minimize conduction of heat along the leaves. The main body of the thermo-couple elements may be shaped as shown in Fig. 1 to present a large surface for heat dissipation. In the construction shown in Figs. 4, 5, and 7, a cylindrical heating- coil 7 is embraced bv the semicircular ends 5 of the thermopiles but is insulated from them by mica shields 6, and a heat-retaining cylinder 8 is placed around the hot junctions, being slotted at 9 to enable it to be passed over the necks 3 of the piles. The frame in which the parts are assembled is provided with screw clamps for pressing the leaves of the piles together, pressing the piles up to the heater, and for maintaining contact between the sides of the piles and the cooling-device shown in Fig. 7. This comprises a series of heat-radiating fins 11 assembled as a stack having a central space 15 to accommodate the thermopiles. The heating-coil is wound on a refractory cylinder 41, Fig. 5, reduced in diameter at its ends to receive metal ferrules 35, so that the surfaces of the ferrules and the cylinder are flush. The wire overlaps the ferrules and is welded to them, electric connections 36, 38 being provided, one passing axially through the cylinder. To assemble the leaves of a pile, a number of strips of the two different metals may be superposed and the edges line-welded together to form a zig.zag strip as shown in Fig. 11, which is then compressed and cut into piles along the lines 46, Fig. 10, the mica or other insulating-leaves 48, 49, Fig. 12, being interposed. The piles may then be clamped and machined to form the necks 3 and the recesses that embrace the heater. In a modification shown in Fig. 14, each couple is formed separately, the two leaves being united at the hot junction 59 only. These couples are superposed, and copper or other cooling-fins 60 are lapped between them at the cold junctions and are welded therein, the couples thereby being welded together also. Another method of forming the piles consists in superposing two sheets of different metals of a width equal to twice the length of the required elements, linewelding the sheets together through their middle, as shown at 62<1> Fig. 15, cutting through the weld along the line 63', and cross-cutting the two strips so formed as previously described. The cold junctions may be united bv electroplating them with a brazing metal, such as silver or spelter, and subsequently heating them by placing the pile in a furnace or by applying a heavy electric current. The main purpose of the battery is to heat the valve filaments of wireless apparatus, the heating-elements of the battery being fed from lighting mains. According to the Specification as open to inspection under Sect. 91 (3) (a), a number of piles 47 shaped as shown in Fig. 13 (Cancelled), may be grouped in a circle, leaving a central space to accommodate the heater 50. This subject-matter does not appear in the Specification as accepted.