摘要 |
<p>A quick-action on off valve comprises a housing (2) including a partition (10) having an interconnecting passageway (18,20) between two chambers (12,14) on opposite sides of the partition. One chamber includes a fixed piston (36,38) and a movable cylinder (40), the cylinder (40) including a resilient disc (44) between its closed end (42) and the port leading from the first chamber (12), and a spring (46) urging the cylinder (40) in the direction tending to close the latter port. Spacing means (48) are provided between the partition (10) and the open end of the cylinder (40) for continuously maintaining communication between the first chamber (12) and the interconnecting passageway (18,20). The difference in the cross-sectional areas of the first port and of the cylinder (40) result in a smaller area of the cylinder (40) being effective to open the valve when the valve is closed, but a larger area of the cylinder (40) being effective to close the valve when the valve is open, thereby providing a quick-action opening and closing of the valve.</p> |