| 摘要 |
The tap or valve is made up of a first tube and a second tube which may be located about a common axis. Each of the tubes has a portion of its wall extending around only a part of its periphery, cut away. One of the tubes is rotatable between an "open position" in which the apertures wholly or partly overlap and a "closed position" in which the apertures are overlapped by a portion of the tube. |
