| 摘要 |
A shut-off valve has two valve flaps (6, 7) defining between them a leakage compartment (22) to collect any liquid leaking past either flap in the closed position. A drainage passage (26) is communicated with the leakage compartment (22), by way of drain ports (23, 24) when the flap valves are closed and sealed off, by blanking off the ports (28, 29) when the flap valves are opened. A flushing port (34) allows access of a flushing/cleansing fluid to the leakage compartment (22). Separate spring loaded valves (46, 47, Fig. 3 not shown) operated by cams (48), (49) may be provided to open and close the drain and flushing ports. Alternatively (Fig. 4, not shown) the drainage passage is opened when only one of the valve flaps is closed, to allow flushing by way of the pipe line rather than by way of a separate flushing port. In this case two drainage passages (opened and closed by respective spring loaded valves 46, 47) are provided. <IMAGE> |
