US2393196A

US2393196A - Thermoelectric device

Info

Publication number: US2393196A
Application number: US470031A
Authority: US
Inventors: Schwarz Ernst
Original assignee: Individual
Current assignee: Individual
Priority date: 1941-07-02
Filing date: 1942-12-24
Publication date: 1946-01-15
Anticipated expiration: 1963-01-15

Description

1946. v E SCHWARZ TE IERMO-ELECTRIC DEVICE Flyl- 3 Filed Dec. 24, 1942 k276i? for I container is exhausted to the degree in which a cylindrical irradiation surface would be utilised in a thermo-electric device.

Referring to Figures 1, 2 and 3, for a. single thermopile suitable for detecting and measuring radiation (e. g. infra-red rays, visible light, ultraviolet rays) the device as a whole comprises a glass container i2 with two leading-in wires l3, I4 fused into the base or foot and connected inside the Container to twoconducting rods i5, i6, say 'of nickel, which enter orifices in metal supports' 20 and 2! held in a metal annulus IT. 'Projecting from the other (outer) side of the supports 20 and 2! are two parallel conducting pillars i8, 59, say of silver, the metal supports 20 or 2i making electric connection between the rods and pillars, orthe rod i5 and pillar I8 may be integral and likewise the rod l6 and pillar 19 may be integral. The two supports 20 and H are separated from one another by a sheet of mica 22 and are also separated from the annulus II by sheets of mica 23 and 24. The conducting rods i5, iii are secured in the supports 20 and 2| as shown in Figure 1 and the supports 20 and 2! are pressed together by an adjusting screw 25. At the outer ends of the pillars i8, is are secured the two

thermoelectric bodies

26 and 21. One, for example the positive element, may be composed of silver, sulphur and selenium melted together and the other or negative element may be composed of copper, silver, tellurium, sulphur and selenium, and each body is in the form of a sturdy little conewith its base on the end of the pillar and its other end or tip outwards. The conducting foil 28 say of gold is secured on its inner face to the tips of the two

cones

26, 21 and the outer face is blackened say with platinum black to form a receiving surface for irradiation. The glass of vacuum required and the surface of the glass may be covered or rendered opaque as at 29 but left clear at the necessary window or irradiation slit 30.

The heat from the highly-conducting receiver 28 goes to the tips of the thermo-

electric bodies

28, 27 and as these have a very low heat conductivity, the heat loss is minimized although the sensitivity is high: further, as the container i2 .is evacuated, conductivity through it is negligible. The sensitivity and the electric resistance may be widely varied by varying the shape and area of the junctions between foil and thermo-electric elements;

Referring to Figure 4, the arrangement is almost the same as in Figures 1, 2 and 3, but in this case the thermo-electric bodies 4 and 32 are cylindrical. As shown, the block 35 is of insulating material such as ivory and the rods l5 and it are connected to the pillars i8 and it by metallic wedges 3 3.

Referring to Figure 5, a convenient method of securing the thermo-electric body, say it, to'its pillar 88 consists in applying a carbon ring 33 to the top of the pillar is, placing a piece of the ready-made composition'on the top of the pillar and subjecting the assembly to direct heat say from a blowepipe flame so as to fuse the composition and weld it on to the top of the pillar i8,'as indicated by the dot and'dash lines. The carbon ring 33 prevents escape of the composition, or in other words retains the composition in its proper place. Thereafter the carbon ring 33 is removed and the thermo-electric body 26 is given the desired shape for example by grinding on a rotating energy disc or theJike.

In cases where it is desired to use two or more the metallic foil as the positive one; and in an electric condenser through this operation a suitable spring or other resilient thermo-electric devices in series this invention provides for very convenient and thermo-electrically efficient arrangements. As above stated the foils are mounted side by side in one surface.

Referring to Figure 6, in the case of three square foils 28, they can be, arranged in the same plane and in line with one another but spaced apart for insulation. Each foil has its two

bodies

26, 21 at the back with their six supporting pillars l8, IS: the first and sixth pillars are electrically connected to the leading-in wires l3, i 6, and positioned in supports 20 and 2| such as those shown in Fi are 2, the second pillar is connected to the third and the fourth to the fifth by metal supports 36 so that the three devices are in series, it being understood that these supports are suitably insulated from each other in a manner similar to that shown in Figure 2. The whole exposed surface of the foils is utilised for receiving irradiation and the heat is transmitted to the tips only of the six bodies. In the same way a square surface as shown in Figure 8 may be divided up into say nine or sixteen square foils slightly spaced apart so that the whole receiver surface is utilised. Thereceiver surface may be cylindrical as shown in Figure 9 with the elements and pillars inside.

There are circumstances in which irradiation may be received in two opposite directions. In that case as shown in Figure 7 the alternate pairs of pillars i8, i9 may project from the metal supports 20, 36 and 2| in opposite directions and have the thermo-electric bodies and foils 28 fixed as above described. One special case where irradiation may be received in two opposite direc tions calls for a differential .thermo-electric device which can detect or measure the difference between the radiation in the two opposite senses. In that case the devices on one side, instead of being connected in series with the devices on the other side, are connected in opposition so that if the thermo electric effects on the two sides are the same, no voltage is generated, but ifthe radiation on the two sides differs, the voltage produced is a measure of the difference in radiation.

There are cases herein referred to as thermorelays where a ray or beam ,may pass across a receiving surface and produce diiferent'thermoelectric effects in accordance with the position of the beam.

In such thermo-relays it is possible to use an irradiation surface in which are fixed two thermo-electric bodies which have the same sign in relation to the receiver. In such a thermo-relay maybe replaced by a foil made of one of the compositions above referred to such that case the two thermo-electric bodies mounted on the pillars are similar to one another and are made of the negative composition.

In any of the structures above described the foil 28 may be secured to the ends or tips of the thermo-

electric bodies

21 or 32 by electric welding preferably employing the discharge of the junctions. In

member (not shown) may be employed to hold the foil in position against the tips prior to and during the welding operatio This invention can be applied to the following I USES:

1. In thermopiles for detecting and measuring 3. In the transformation of radiation energy (say from the sun) into electric current;

4. For measuring degree of vacuum (as the sensitivity of the thermo-electric device increases as the gaseous pressure diminishes);

5. In electrical relays afiected by radiation as in burglar alarms;

6. In pyrometers for measuring the total radiation from any body;

'7. In differential or thermo-relays.

I claim:

1. A thermo-electric device comprising a pair of pillars of thermal and electrical conducting material, a base structure for supporting one end of each of said pillars with the other ends thereof adjacent but spaced from each other, a thermoelectric element secured to each of said pillars, each element forming an axial continuation of one of said pillars and having a base portion welded to said other end of said one of said pillars, said thermo-electric elements each being a small sturdy body of a thermo-electric composition having low heat conductivity, and a conducting foil element welded to both said bodies at their free ends. V

2. A thermo-electric device comprising a pair of pillars of thermal and electrical conducting material, a base structure for supporting one end of each of said pillars with the other ends thereof adjacent but spaced from each other, a thermo-electric element secured to each of said pillars, each element forming an axial continuation of one of said pillars and having a base portion welded to said other end of said one of said pillars, said thermo-electric elements each being a small sturdy body of a thermo-electric composition low heat conductivity, and a conducting foil element welded to both said bodies at their free ends, the ends of said bodies welded to said foil being smaller in diameter than said base portions.

3. A thermo-electric device comprising a pair of pillar members each having a metal body portion and a tip portion of a thermo-electric composition, said tip portion of each pillar forming an axial continuation of the body portion thereof and having a base portion welded to an end area of said body portion, said tip portions of said pillars being positioned adjacent each other, and an electrically conducting member joining the ends of said tip portions to form a thermopile.

4. A thermo-electric device comprising a pair of pillar members each having a metal body portion and a tip portion of a thermo-electric composition, said tip portion of each pillar forming an axial continuation of the body portion thereof and having a base portion welded to an end area of said body portion, said tip. portions of said pillars being positioned adjacent each other, the composition of one oi said tip portions having positive thermo-electric characteristics and the composition of the other tip portion having negative thermo-electric characteristics, and a metal member joining the exposed ends of said tip portions to form a thermopile.

5. A thermo-electric device comprising a pair of pillar members each having a metal body portion and a tip portion of a thermo-electric composition, said tip portion of each pillar forming an axial continuation of the body portion thereof and having a base portion welded to an end area of said body portion, said tip portions of said pillars being positioned adjacent each other, and a metal foil united to the ends of said tip portions to form a thermopile and having its outer surface adapted for irradiation.

6. A thermo-electric device comprising a pair of pillar members each having a metal body portion and a tip portion of a thermo-electric composition, said tip portion of each pillar forming an axial continuation of the body portion thereof and having a base portion welded to an end area of said body portion, said tip portions of said pillars being positioned adjacent each other, and a metal foil welded to the outer ends of and joining said tip portions.

7. A thermo-electric device as defined in claim 4 in which the tip portions are conical and said metal member is a metal foil welded to and Joining the apexes of said conical tip portions.

8. A thermo-electric device comprising a pair of pillar members each having a metal body portion and a tip portion of a thermo-electric composition, said tip portion of each pillar forming an axial continuation of the body portion thereof and having a base portion welded to an end area of said body portion, said tip portions of said pillars being positioned adjacent each other,

the composition of said tip portions being sub-' stantially the same so as to have the same polarity, and an electrically conducting member having a thermo-electric composition of opposite polarity to that of said tip portions welded to and joining the ends of said tip portions to form a thermopile.

9. A thermo-electric device as defined in claim 5 in which the tip portions are screened from irradiation by the metal foil.

10. A thermo-electric device as defined in claim 6 which includes means for detachably supporting the ends of said pillar members opposite said tip portions to hold said pillar members in spaced parallel relation, and means to electrically insulate said last named ends from each other.

ERNST SCHWARZ.