| 摘要 |
<p>630,031. Valves. FLIGHT REFUELLING, Ltd., LEGGE, C. N., and MANNING, W. O. April 2, 1947, No. 8945. [Class 135] In a valve opened by the pressure of inflowing liquid and closed by a piston resiliently connected to the valve and responsive to the pressure in a chamber open at all times to the inflowing liquid and provided with an orifice which can be closed to permit of the build-up of pressure within the chamber, the resilient means permits the valve to open without piston movement on the pressure of the inflowing liquid reaching a predetermined value. As applied to the filling of aircraft fuel tanks, the valve comprises a casing 1, Fig. 1, having inlet and outlet ports 2, 3 respectively and formed with a chamber 7 having an orifice 8 controlled by a buffer 9 carried on the arm 10 of a flaot 12 which rises and falls in accordance with the liquid level in the tank. The chamber 7 houses a piston 4b provided with a slidable tubular member 6 carrying a valve closure member 4a. Springs 5 normally hold the valve and piston in spaced relationship with each other, but permit the opening of the valve with no piston movement on the pressure in the filling hose exceeding a predetermined value when held closed by a light spring 14 and the pressure in the chamber 7 when the tank is full or substantially full. With the tank empty, the orifice 8 is open. On connection of the filling hose the valve 4a is opened and the piston 4b moved downwards against the spring 14 by inflowing fuel which passes into the tank through the outlets 3 and the member 6, whence the float 12 rises. When the tank is nearly full, the orifice 8 is substantially closed by the buffer 9 which permits the build-up of pressure in the chamber 7 to close the valve 4a and stop the high pressure filling of the tank whilst still allowing the final filling through the tubular member 6 and the orifice 8. The orifice 8 may be controlled manually or electrically. In a modification, the buffer 9 is replaced by a round-headed screw which loosely carries a metallic closure member. The outlet end of the member 6 may be provided with a spring-loaded, non-return ball valve.</p> |
