| 摘要 |
<p>A hot water system has a aperture in the hot water line normally blocked by a liquid and gas filled vial which is sealed against the aperture to close it off. However, when hot water in the system reaches a predetermined temperature the expansion of the liquid in the vial fractures it, unblocking the aperture and allowing hot water to escape from the hot water line. Cold water coming into the cylinder will prevent any further temperature rise.</p> |
