| 摘要 |
PURPOSE:To improve performance and reliability of a vacuum tube type heat collector, by using a heat collecting plate with a selective absorption film that is preheated in a hydrogen-gas containing atmosphere. CONSTITUTION:A vacuum tube type heat collector is composed of a transparent soda glass tube 1, U-shaped copper pipe 2, 3, heat collecting plate 4 obtained by applying nickel plating over the surface of a copper plate and then coating the same with a black chromium film, alloy plate 5, fixing metal 6 and an evacuating portion 7. The heat collecting plate 4 is degassed in a hydrogen-gas containing atmosphere at a preheating temperature higher than 200 deg.C and then drawn to a vacuum under the state heated to about 400 deg.C, whereby the time required for evacuation can be shortened. With such an arrangement, it is enabled to use the black chromium film in the vacuum tube heat collector although use of the black chromium film in a vacuum tube type heat collector has been considered difficult heretofore, so that the performance and reliability of the heat collector can be improved. |
