초록 ▼

A tubular radiation absorbing device (1) designed for a solar heating application is described. The tubular radiation absorbing device has a metal central tube (3) and a glass tubular jacket (2) surrounding the central tube (3). A folding bellows (11) is connected between the central tube (3) and th

A tubular radiation absorbing device (1) designed for a solar heating application is described. The tubular radiation absorbing device has a metal central tube (3) and a glass tubular jacket (2) surrounding the central tube (3). A folding bellows (11) is connected between the central tube (3) and the tubular jacket (2), so that the tubular jacket and the central tube are movable relative to each other. A connecting element (20) connects an inner end of the folding bellows (11) with the central tube (3) and extends from the inner end of the folding bellows (11) through an inner annular space (30) between the folding bellows (11) and the central tube (3). The connecting element includes at least a part of a hydrogen window (50). A getter (6) is arranged in an outer annular space (33) between the folding bellows (11) and the tubular jacket (2).

대표청구항 ▼

What is claimed is new and is set forth in the following appended claims: 1. A tubular radiation absorbing device for solar heating applications, which comprises a central tube (3); a glass tubular jacket (2) surrounding the central tube (3) so as to form a ring-shaped space (4) between the tubular

What is claimed is new and is set forth in the following appended claims: 1. A tubular radiation absorbing device for solar heating applications, which comprises a central tube (3); a glass tubular jacket (2) surrounding the central tube (3) so as to form a ring-shaped space (4) between the tubular jacket and the central tube; an expansion compensating device (10) connected between the central tube (3) and the glass tubular jacket (2), so that the tubular jacket and the compensating device are movable longitudinally relative to each other and so as to form an inner annular space (30) between the central tube (3) and the expansion compensating device (10); a connecting element (20) connecting an inner end (12) of the expansion compensating device (10) with the central tube (3) and extending from the inner end (12) of the expansion compensating device through said inner annular space (30), wherein said inner annular space (30) is divided into a first annular space (31) between the central tube (3) and the connecting element (20) and a second annular space (32) between the connecting element (20) and the expansion compensating device (10), said second annular space (32) being connected with an outer atmosphere; and at least one hydrogen window (50) arranged in the connecting element (20) so that the at least one hydrogen window (50) is protected from incident solar radiation by the expansion compensating device (10) and so that hydrogen collecting in the first annular space (31) passes through the at least one hydrogen window (50) into the second annular space (32) and subsequently escapes into the outer atmosphere. 2. The tubular radiation absorbing device as defined in claim 1, wherein the connecting element (20) extends at least up to the vicinity of an outer end (13) of the expansion compensating device (10). 3. The tubular radiation absorbing device as defined in claim 1, wherein the first annular space (31) has a width of from 1 to 10 mm. 4. The tubular radiation absorbing device as defined in claim 3, wherein said width is from 1 to 2 mm. 5. The tubular radiation absorbing device as defined in claim 1, wherein said at least one hydrogen window (50) comprises palladium or a palladium alloy. 6. The tubular radiation absorbing device as defined in claim 1, wherein an entire portion of the at least one hydrogen window (50) is radially between the central tube (3) and the expansion compensating device (10) so that the at least one hydrogen window is completely protected from said solar radiation by said expansion compensating device. 7. The tubular radiation absorbing device as defined in claim 1, wherein the hydrogen window (50) has a section (51) extending into the ring-shaped space (4) and the hydrogen window (50) is arranged on a side of the central tube (3) so that direct irradiation with concentrated solar energy is avoided. 8. The tubular radiation absorbing device as defined in claim 1, wherein at least one getter (60) is arranged in an outer annular space (33) between the tubular jacket (2) and the central tube (3). 9. The tubular radiation absorbing device as defined in claim 1, wherein the central tube (3) is a metal tube and further comprising a glass-metal transitional element (40) connecting an outer end (13) of the expansion compensating device (10) with the glass tubular jacket (2). 10. The tubular radiation absorbing device as defined in claim 9, wherein a getter (60) is arranged in a section (34) of the outer annular space (33) between the expansion compensating device (10) and the glass-metal transitional element (40). 11. The tubular radiation absorbing device as defined in claim 10, wherein the glass-metal transitional element (40) has a circumferential collar (42) on an outer end thereof and the circumferential collar (42) is connected to an outer end (13) of the expansion compensating device (10) by an annular disk (43). 12. The tubular radiation absorbing device as defined in claim 10, wherein the glass-metal transitional element (40) has a circumferential step (41). 13. The tubular radiation absorbing device as defined in claim 12, wherein the getter is axially connected between the circumferential step (41) and an annular disk (43), said annular disk (43) connecting an outer end of the expansion compensating device (10) to an outer end of the glass-metal transitional element (40). 14. The tubular radiation absorbing device as defined in claim 10 wherein the getter comprises a low-activation-energy material. 15. The tubular radiation absorbing device as defined in claim 1, wherein the central tube (3) is a metal tube. 16. The tubular radiation absorbing device as defined in claim 1, wherein the expansion compensating device (10) is a folding bellows (11). 17. The tubular radiation absorbing device as defined in claim 1, and formed as part of a parabolic trough collector in a solar heating plant. 18. The tubular radiation absorbing device as defined in claim 1, wherein said at least one hydrogen window (50) is arranged sufficiently close to said central tube (3) so that in operation said at least one hydrogen window (50) has a temperature over 200° C.