US4291680A — Double-walled glass solar energy collector

Claim 1

Independent Claim 169 words

A solar energy collector comprising, in combination, a transparent outer glass tube, an inner glass tube concentrically inserted in said outer tube with an annular space defined between the outer wall of the inner tube and the inner wall of the outer tube, means for sealing the axial ends of said tubes together to permit evacuating the said annular space, means for flowing a heat transfer fluid thru the inner glass tube, a solar energy absorbent coating on the outer wall of said inner glass tube, thereby trapping solar energy incident on said outer tube within said heat transfer fluid and said inner glass tube, said inner glass tube having at least one axial portion of its length deformed inwardly to form a bellows-shaped expansion section to absorb differences in expansion of said inner and outer tubes, said bellows-shaped section having the same outer diameter as said inner tube and the outer diameter of the inner tube being at least 85% of the inner diameter of the outer tube.

Claim 2

Dependent Claim 169 words

A solar energy collector comprising, in combination, a transparent outer glass tube, an inner glass tube concentrically inserted in said outer tube with an annular space defined between the outer wall of the inner tube and the inner wall of the outer tube, means for sealing the axial ends of said tubes together to permit evacuating the said annular space, means for flowing a heat transfer fluid thru the inner glass tube, a solar energy absorbent coating on the outer wall of said inner glass tube, thereby trapping solar energy incident on said outer tube within said heat transfer fluid and said inner glass tube, said inner glass tube having at least one axial portion of its length deformed inwardly to form a bellows-shaped expansion section to absorb differences in expansion of said inner and outer tubes, said bellows-shaped section having the same outer diameter as said inner tube and the outer diameter of the inner tube being at least 85% of the inner diameter of the outer tube.

Claim 3

Dependent Claim 32 words

The apparatus of claim 1 wherein said inwardly deformed portion is of re-entrant arcuate configuration and has a wall thickness at least equal to the non-deformed portions of said inner glass tube.

Claim 4

Dependent Claim 121 words

In a solar energy collector of the type having a pair of concentrically disposed glass tubes sealed together at their opposed axial ends to define an enclosed annular space therebetween, said annular space being highly evacuated and the outer surface of the inner tube being covered with a solar energy absorbent coating to trap solar energy incident on the outer tube within said inner tube, the improvement comprising at least one axial portion of said inner tube being deformed inwardly to form a bellows-shaped expansion section, each said bellows-shaped section being essentially torodial and having the same outer diameter as the inner tube and being effective to absorb differences in thermal expansion of said integrally united inner and outer glass tubes.

Claim 5

Dependent Claim 121 words

In a solar energy collector of the type having a pair of concentrically disposed glass tubes sealed together at their opposed axial ends to define an enclosed annular space therebetween, said annular space being highly evacuated and the outer surface of the inner tube being covered with a solar energy absorbent coating to trap solar energy incident on the outer tube within said inner tube, the improvement comprising at least one axial portion of said inner tube being deformed inwardly to form a bellows-shaped expansion section, each said bellows-shaped section being essentially torodial and having the same outer diameter as the inner tube and being effective to absorb differences in thermal expansion of said integrally united inner and outer glass tubes.

Claim 6

Dependent Claim 26 words

The apparatus of claim 3 wherein said inwardly deformed portion has a wall thickness at least equal to the non-deformed portions of said inner glass tube.

Claim 7

Dependent Claim 91 words

The combination defined in claim 1 wherein said means for flowing a heat transfer fluid through the inner glass tube comprises an outwardly flared end portion on said outer glass tube, a fluid conduit having a similarly outwardly flared end portion disposed adjacent the said outwardly flared end portion of said outer glass tube, a sleeve of elastomeric material snugly surrounding both said outwardly flared portions, and an adjustable clamp surrounding said sleeve and compressing same into fluid-sealing and mechanically-connecting engagement with said outer glass tube and said adjacent fluid conduit.

Claim 8

Dependent Claim 25 words

The apparatus defined in claim 5 wherein said adjustable clamping element is provided with a mounting flange adapted for detachable securement to a support rail.

Claim 9

Dependent Claim 15 words

The apparatus defined in claim 5 wherein said fluid conduit comprises another solar energy collector.

Claim 10

Dependent Claim 117 words

A tubular solar collector comprising a first glass tube open at its opposite axial ends, and a second glass tube whose I.D. is slightly greater than the O.D. of said first tube, said first tube having integral, inwardly directed, annular, axially extending bellows segments formed in the tube wall near one of its open ends, an opaque solar energy absorbing annular coating layer extending over a substantial axial portion of the outermost surface areas of said first tube, said second tube being transparent and having its opposite open ends fusion sealed with glass of said first tube at axially spaced points therealong, said opposite end seals providing an evacuated chamber between the first and second glass tubes.

Claim 11

Dependent Claim 117 words

A tubular solar collector comprising a first glass tube open at its opposite axial ends, and a second glass tube whose I.D. is slightly greater than the O.D. of said first tube, said first tube having integral, inwardly directed, annular, axially extending bellows segments formed in the tube wall near one of its open ends, an opaque solar energy absorbing annular coating layer extending over a substantial axial portion of the outermost surface areas of said first tube, said second tube being transparent and having its opposite open ends fusion sealed with glass of said first tube at axially spaced points therealong, said opposite end seals providing an evacuated chamber between the first and second glass tubes.

Claim 12

Dependent Claim 16 words

The solar collector of claim 8 wherein each bellows segment is of a substantially toroidal configuration.

Claim 13

Dependent Claim 78 words

The collector of claim 8 or 9 which includes a plurality of tubular collectors and means including an elastomeric sleeve connecting one open end of the first glass tube of one of the collectors to an open end of the first glass tube of another of the tubular collectors, said means providing for flow of a heat exchange medium successively through each first glass tube of the plural collectors and preventing substantial heat loss from heated medium therein.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1984-09-28	1985-03-30	1985-09-29	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1988-09-28	1989-03-30	1989-09-29	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1992-09-28	1993-03-30	1993-09-29	$7700.00	Window Closed / Lapsed

Double-walled glass solar energy collector

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