GB763513A - Improvements in or relating to valves - Google Patents

Abstract

763,513. Valves. SHELL REFINING & MARKETING CO., Ltd. June 30,1954 [July 6, 1953], No. 18681/53. Class 135. In a screw-actuated gate valve used, e.g. in the filling and emptying of tanks on an oil tanker or other ship, the valve operating spindle is operably associated with the output shaft of a portable reversible power unit detachably mounted on the valve superstructure, the unit including control means engageable with an actuating member on the valve which moves in dependence upon the position of the valve member to operate the unit to within a half hand wheel turn of the valve member reaching either its fully open or fully closed position, the control means then disengaging itself from the actuating member to stop the unit. As shown, a bracket 12, Fig. 1, on the valve superstructure is formed with a bore 13 slidably mounting a cylindrical portion 14 of a portable power unit 11 having an output shaft 10 mounting a bevel pinion 9 engageable with a bevel gear 8 secured to the hand wheel 7 which is keyed to the valve-operating spindle 5. An externally screw-threaded bush 33 secured to the spindle 5 co-operates with a non-rotatable, reciprocating collar 34 having a cam surface 35 engageable with a spring- loaded actuating member 32 which in turn engages a lever 28 pivotally mounted on the unit 11. The lever 28 actuates a loose ball valve 25, Fig. 2, in the supply line to the power unit which, as shown, is a rotary reversible pneumatic motor. In operating the valve from its fully open or fully closed position it is first necessary to give the hand wheel 7 a half turn until the member 32 engages the cam surface 35 whence the ball 25 is unseated and compressed air is supplied to operate the motor and power-operate the valve. A manual control lever 23 may be operated to reverse the motor or stop it at any instant so that if desired the valve member may be brought to any intermediate position. The valve shown in Fig. 1 is of the rotatable, non-rising spindle type. The portable power unit may be fitted to valves having a non-rotating spindle which rises through a hand wheel secured against axial movement. In this construction, the valve spindle 5 is screw-threaded at its upper end and engages an internal thread formed in the bush on which is secured the bevel gear 8 and the hand wheel 7. Another type of valve to which the power unit may be fitted is one having a rising, rotatable spindle, the hand wheel in this case being secured to the spindle to rise therewith. In this construction, the upper end of the spindle 5 is of square crosssection and coacts with a square hole in the bush. The pneumatic motor may be replaced by an electric motor or by a rotary or reciprocating hydraulic motor. Since the power unit is readily detachable from the valve only one unit is necessary for use with any number of valves.