| 摘要 |
A valve assembly for providing a measured amount of fluid under pressure. A pair of valves are disposed, one upstream and one downstream of a measuring chamber. The upstream valve is normally closed to the measuring chamber and the downstream valve is normally open to the measuring chamber. A lost motion connection is provided between the two valves so that the downstream valve is closed and then the upstream valve is opened to admit fluid under pressure into the measuring chamber. Release of the connection results in reclosing of the upstream valve followed by reopening of the downstream valve to permit dispensing of the measured charge from the measuring chamber. The assembly may be manually or mechanically or electrically actuated.
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