GB1279471A - Thermoelectric generators - Google Patents

Abstract

1279471 Thermoelectric devices SIEMENS AG 23 Oct 1969 [24 Oct 1968] 52073/69 Heading H1K A nuclear powered thermoelectric generator is enclosed within a container which acts both as a heat sink and as a radiation shield. As shown, a casing 7 containing a radioactive fuel forms the heat source for an assembly of pairs of thermoelectric elements 8 enclosed in a cup 1 surrounded by a sleeve 2 both of which are secured to a cap 3 by means of screws 4 and 5. The cup 1, sleeve 2 and cap 3 form a radiation tight shield and may be of uranium, lead or steel. Several alternative forms of the thermocouples and their mountings are illustrated in the figure. Each of the P and N type elements 8a are formed of two sections connected in series by silver braids 15. The inner hot sections may be of Ge-Si alloy and the outer cold sections may be of PbTe or Bi 2 Te 3 . The hot ends are connected by Mo-Si alloy bridges 9 which are in direct contact with the casing 7. The cold ends are contacted by silver plates 10 which are secured to mounting pins 13 by means of a layer of insulating material which may be of alumina or beryllia metallized and soldered to the plates 10 and pin 13. Each of the P and N type elements 8b comprises a single section secured to bridges 9a which are spaced from the casing 7 to reduce thermal stress the heat transfer being achieved by radiation across the gap. Pins 13a are provided with threaded studs which are inserted in bores 14 in the cup 1 and secured by nuts 16, pins 13b are additionally provided with tapered sections which fit into corresponding recesses in the cup, and pins 13c are provided with tapered sections and are secured by studs screwed into threaded bores in the cup 1. In all these constructions adjacent thermocouple pairs are connected in series by silver braids 11 secured to the silver plates 10. Pin 13d is conically tapered and fits into a hole in cup 1 in such a manner that the thermocouple assembly may be inserted from the outside and secured by an externally threaded nut 16. Pin 13d also has a bore through which extend terminals 18 connected to the ends of the thermoelements, and adjacent thermocouple pairs are connected in series by silver braids extending between terminals 12 in grooves in the outside face of cup 1. Resilient members may be provided between silver plates 10 and the associated pins 13. The links of the thermoelements are surrounded with thermally insulating material 19.