| 摘要 |
A liquid flow control valve comprising a casing (10) and a sealing member (22) within the casing, wherein the sealing member divides the casing into a first chamber (24) and a second chamber (26), wherein the sealing member (22) provides for restricted liquid flow (40) from the first (24) to the second chamber (26), the casing the first chamber (24) and a liquid outlet port (20), a valve operating member (32, 30) in the second chamber (26) and operable on the sealing member (22) and co-operable therewith to seal the outlet port (20), wherein the valve operating member (32, 30) is operable by liquid pressure due to liquid which flows into the second chamber (26) from the first chamber (24) via the sealing member's restricted flow passage (40) to initially co-operate with the sealing member (22) to substantially prevent liquid flow from the second chamber (26) through the outlet port (20) via the sealing member (22), and subsequently to co-operate with the sealing member (22) to seal the outlet port (20), wherein the operating member (32, 30) is externally actuable (via arm 32, typically by a float) to break the seal for liquid to flow from the first and second chambers, through the outlet port and is released upon removal of the external actuation for operation by said liquid pressure, wherein the restricted liquid flow (40) into the second chamber and the pressure thereof relative to liquid pressures at the outlet port provides for controlled closure of the valve.
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