| 摘要 |
<p>A curved pipe (1) has a flange (2) and passes through a chamber (3), which is formed by two curved sides meeting at points top and bottom. A prism (4), also with curved sides, rotates on a shaft (5) at one of its corners, mounted in one side of the chamber. In the shut position, the prism blocks the pipe. Rotation of the prism by a lever or worm-shaft (8) such that one side slides over the curved surface of the chamber. This moves it into the upper half of the latter, opening the pipe.</p> |
