| 摘要 |
<p>1,273,762. Valves. FESTO MASCHINENFABRIK GOTTLIEB STOLL. 20 June, 1969 [20 June, 1968], No. 31228/69. Heading F2V. A multi-way valve has a closure member 1, Fig. 1, held against its seat by pressure derived from the controlled fluid, the pressure being relieved or reversed each time the member is operated. Pressure at the supply port 6 passes through one or two narrow bore passages 26, 27 or through portions of the closure member made from porous material to act on the upper face 8. Opening one of a pair of liners 11, 12 reduces the pressure on the face 8 and causes the closure member to move axially into engagement with one of two resilient stops 17, 18. The closure member may be encased in rubber or synthetic material to receive fine teeth or notches in the seat. In Fig. 4, the lines 35, 36 for relieving the sealing pressure and for causing axial movement of the closure member are controlled by spring-loaded valves 35a, 36a. Accumulators 41, 42 provide sufficient pressure to ensure the valve completes its movement. In a further modification, two inlet channels 44, 45, Fig. 5, and three relief channels 48, 49, 50 may be connected by ports 46, 47 to allow supply pressure to act on the upper face of the closure member so that there is no tendency to tilt about an axis A-A. The passages in the seat and closure may be shaped to reduce losses due to changes in the direction of fluid flow. Fig. 7 shows a rotary closure member 56 for connecting a supply port 64 alternately with delivery ports 62a, 62b, the delivery port not connected with supply being connected to a relief port 63a or 63b. Fluid to actuate the closure member is supplied to spacers 60 and 61 through control lines 69 and 70. In a further modification, spring or magnetic loading means are used to ensure the closure member is held against its seat in the event of loss of fluid pressure from the space above the closure member.</p> |
