Radioisotope thermoelectric generator

Claim 2

An improved thermoelectric generator comprising: a cylindrical member formed of a high radiation capturing material having at least one open end; a radioisotopic heat source positioned within said member; thermal insulation means positioned within said member so as to direct the heat produced by said heat source towards said at least one open end; a radiation shielding plug between said heat source and said at least one open end axially aligned with said cylindrical member having its inner surface in thermal contact with said heat source and its peripheral edge surface enclosed by said insulation means; and closure means for said member overlying said at least one open end of said member, said closure means including thermoelectric conversion means in planar form in heat-receiving relationship With said radiation shielding plug, said conversion means consisting of a unitary replaceable assembly operatively disposed within and removable as a unit from said thermoelectric generator and comprising a metallic plate acting as a thermal heat sink and forming the cover assembly of the thermoelectric generator, a body of thermal insulating material defining a plurality of spaced through openings, a plurality of thermoelectric elements carried within said spaced openings, hot shoes connected to respective ends of selected adjacent thermoelectric elements, bus straps operatively connected to the other ends of selected adjacent thermoelectric elements whereby said body, said thermoelectric elements, said hot shoes and said bus straps comprise an electrical subassembly of said module, a bellows structure having a closed end comprising a heat conductive cover, an open end and a bellows portion, the closed end of said structure overlying said hot shoes of said electrical subassembly but electrically insulated therefrom, the bellows portion of the structure surrounding said electrical subassembly, the open end of said structure characterized by an outwardly directed flange, said heat sink being of sufficient size to extend outwardly of said bellows portion when overlaid therewith to allow the flange of said bellows structure to be detachably engaged with said heat sink, the flange of said bellows structure being detachably engaged with said heat sink to define an enclosed sealed chamber in which said electrical subassembly is contained, said heat sink being electrically insulated from said bus straps, the bellows portion of said bellows structure being expanded during engagement with said heat sink to exert a compressive force on said thermoelectric elements via said hot shoes and bus straps to enhance conduction of thermal energy from said closed end of said bellows structure to said heat sink through said electrical subassembly, and means electrically connected to said bus straps extending out from said chamber in fluid sealed fashion.

Claim 3

The thermoelectric generator of claim 3, wherein said metallic heat sink plate contains a plurality of holes generally in line with said through openings carried by said body of insulating material and which further comprises alignment pistons of thermally conductive material carried by said heat sink holes, means biasing said pistons outwardly, against said thermoelectric elements, electrical insulation means positioned between the outer ends of said alignment piston and said thermoelectric elements, said bellows assembly overlying said thermoelectric conversion assembly and said associated alignment pistons.

Claim 4

The thermoelectric generator of claim 4, further including a spring positioned within each hole behind respective alignment pistons, wherein the spring constant of the bellows portion of said bellows structure is less than the combined spring constant of the individual alignment springs.

Claim 5

The module as claimed in claim 1 further including an O-ring sandwiched between said flange and the face of said heat sink plate to provide a high temperature gastight seal for said thermoelectric conversion assembly.

Claim 6

The module as claimed in claim 1 further including getter means within the chamber formed by said bellows assembly and said heat sink metallic plate for absorbing active gases within said chamber.

Claim 7

The module as claimed in claim 1 wherein a thin mica sheet is positioned between said heat-conductive cover and said thermoelectric conversion assembly to electrically insulate said thermoelectric elements from said cover.

Claim 8

The module as claimed in claim 1 further including means for out-gassing said chamber formed by said bellows structure and said heat sink plate subsequent to said assembly of said module.

Claim 9

An improved sandwich-type, thermoelectric conversion module comprising: an annular metallic plate acting as a thermal heat sink including thermal energy dissipating fins on one side thereOf and a heat receiving face for transmitting thermal energy on said opposite side, a plurality of spaced annular recesses formed within said thermal transmitting face, a thermoelectric conversion assembly including an annular disc formed of insulation material having spaced apertures corresponding to said heat sink recesses, thermoelectric couples carried by said insulation disc with the individual thermoelectric elements positioned within said disc apertures, electrically conductive busstraps soldered to respective ends of adjacent couples to form an appropriate electrical circuit, metallic alignment pistons carried within said heat sink recesses, the heat sink ends of said alignment pistons being recessed, coil springs positioned within said piston recesses and acting to bias said alignment pistons outwardly from said heat sink, the opposite end of said alignment pistons being concave, hemispherical metallic buttons positioned within said concave ends and having their flat surface in contact with respective busstraps, insulation means carried by said flat button surfaces to prevent passage of electrical energy but allow free passage of thermal energy, electrical insulation means covering the face of said thermoelectric conversion assembly remote from said heat sink, a bellows assembly including a heat conductive cover overlying said thermoelectric conversion assembly and said alignment pistons and a bellowslike sidewall surrounding said thermoelectric assembly and means for coupling respective ends of said sidewalls to said heat sink and said cover, and said bellows wall being expanded during assembly to cause said thermoelectric elements to be compressed between said cover and said alignment pistons to enhance conduction of thermal energy from said cover to said heat sink through said thermoelectric assembly and said alignment pistons.

Claim 10

The module as claimed in claim 10 further including getter means within said chamber intermediate of said cover and said thermoelectric conversion assembly for absorbing the active gases within the chamber formed thereby.

Claim 11

The module as claimed in claim 10 wherein said bellows assembly includes an annular flange carried by said bellowslike sidewall remote from said cover, said flange including a series of spaced bolt holes, threaded apertures carried by said heat sink plate spaced radially of said piston receiving recesses, sealing means between said flange and said heat sink face and a plurality of bolts for clamping said flange to said heat sink metallic plate.

Claim 12

A sandwich-type thermoelectric conversion module comprising: a metallic plate acting as a thermal heat sink having a plurality of recesses formed therein; a thermoelectric conversion assembly including a plurality of spaced thermoelectric elements generally in line with said recesses; alignment pistons of thermally conductive material carried by said recesses; means biasing said pistons outwardly from said heat sink against said thermoelectric elements; means for electrically insulating said heat sink from said thermoelectric elements; a bellows assembly including a heat conductive cover overlying said thermoelectric conversion assembly and said associated alignment pistons, said bellows assembly including a bellowslike sidewall surrounding said thermoelectric assembly; means for coupling one end of said sidewall to said cover; and means for removably coupling said other end of said sidewall to said heat sink, said bellowslike wall being expended during assembly to cause said thermoelectric elements to be compressed between said cover and respective said alignment pistons to enhance conduction of thermal energy from said cover to said heat sink through said thermoelectric assembly.

Claim 13

An improved thermoelectric generator comprising: a cylindrical member formed of a high radiation capturing material having at least one open end; a radioisotopic heat source positioned within said member; thermal insulation means positioned within said member so as to direct tHe heat produced by said heat source towards said at least one open end; a radiation shielding plug between said heat source and said at least one open end axially aligned with said cylindrical member having its inner surface in thermal contact with said heat source and its peripheral edge surface enclosed by said insulation means; and closure means for said member overlying said at least one open end of said member, said closure means including thermoelectric conversion means in planar form in heat receiving relationship with said radiation shielding plug, said conversion means including a metallic plate acting as a thermal heat sink having a plurality of recesses formed therein, a thermoelectric conversion assembly including a plate formed of insulation material having perforations generally in line with said recesses and a plurality of spaced thermoelectric elements carried within said perforations, alignment pistons of thermally conductive material carried by said recesses, means biasing said pistons outwardly against said thermoelectric elements and a bellows assembly including a heat conductive cover overlying said thermoelectric conversion assembly and a bellowslike sidewall surrounding said thermoelectric assembly and means for coupling respective ends of said sidewall to said heat sink and said cover, whereby said bellows wall, being expanded during assembly, causes said thermoelectric elements to be compressed between said cover and respective alignment pistons to enhance conduction of thermal energy from said cover to said heat sink through said thermoelectric assembly while acting to press the outer surface of said cover in heat-receiving contact with said radioisotopic heat source capsule when said closure means is coupled to said cylindrical member.

Claim 14

A sandwich-type thermoelectric conversion module comprising: a metallic plate acting as a thermal heat sink; a thermoelectric conversion assembly including a plurality of spaced thermoelectric elements; thermal insulating means disposed between said spaced thermoelectric elements, said means of the type which generates reactive gasses at the operating temperature of said module to detrimentally affect said thermoelectric elements; a bellows assembly including a heat conductive cover overlying said thermoelectric conversion assembly and a bellowslike sidewall surrounding said thermoelectric assembly; a thin sheet of zironium foil positioned between said thermoelectric conversion assembly and said cover, whereby said foil will absorb said reactive gasses; and means for coupling respective ends of said sidewall to said heat sink and said cover, said bellows wall being expanded during assembly to cause said thermoelectric elements to be compressed between said cover and said metallic plate to enhance conduction of thermal energy from said cover to said heat sink through said thermoelectric assembly.

Claim 15

An improved thermoelectric generator assembly comprising: a cylindrical ferrous container having at least one open end; thermal insulation means in solid configuration retaining form positioned within said container and defining a space internally thereof; a shielded heat source including a cylindrical radioisotopic capsule surrounded by radioactive shielding means formed of a material from the group consisting of tungsten, uranium and alloys thereof, said shielded heat source being removably retained within said space; and closure means for said container overlying at least one open end thereof, said closure means including thermoelectric conversion means in planar form in heat-receiving relationship with said shielding means, said thermal insulation means directing heat produced by said heat source toward said closure means, said radioactive shielding means being of sufficient thickness to reduce radiation from said capsule sufficiently to permit safe handling of said capsule for substantially short periods of time and said ferrous container being of sufficient thickness so that the total shielding effect of Said shielding means and said container will reduce radiation emitted therethrough to an acceptable level for extended periods of exposure.

Claim 16

The generator as claimed in claim 16 wherein said thermoelectric conversion means comprises a thermoelectric module including a platelike heat sink and means for removably coupling said thermoelectric module to the open end of said cup-shaped container.

Claim 17

The generator as claimed in claim 16 wherein said thermal insulation means comprises fibrous insulation material and said container further includes means carried thereby for allowing out-gassing of said fibrous insulation material subsequent to assembly of said container and said thermoelectric conversion means.

Claim 18

The generator as claimed in claim 16 wherein said thermal insulation means comprises a generally cup-shaped insulation mass surrounding said radioactive shielding means, and said generator assembly further includes an annular retaining ring having an inner diameter less than the diameter of said radioactive shielding means and an outer diameter in excess thereto, and means for coupling said retaining ring to the end of said radioactive shielding means whereby said ring overlies said capsule with the ring outer periphery imbedded in said insulation mass to prevent axial shifting to said radioactive shielding means with respect to said container.

Claim 19

The assembly as claimed in claim 16 wherein said cylindrical member comprises a cast iron cylinder of considerable thickness, and said thermoelectric conversion means comprises a planar-type module including a perforated insulating plate with spaced thermoelectric elements carried thereby and means for removably attaching said thermoelectric conversion module to the open end of said cast iron cylinder.