Evacuated solar collector tube

摘要

The present invention has two tubes arranged concentrically and separated by a vacuum. The internal tube is of thin wall steel construction with a selective absorbing coating. The external tube is a hard glass material such as, for example, Pyrex. The vacuum tight seal between the concentric tubes consists of an accordian-pleated semi-rigid material such as copper connected to the inner tube. The semi-rigid material is then fused to a thermally insulating, vacuum tight spacer. Finally, the spacer is fused to the outer glass tube. Additional shatter protection may be derived from a reflective coating extending from midway along the ceramic spacer over the ceramic-glass seal, and along the glass for several inches.