GB200831A - Improvements in flow control valves - Google Patents

Abstract

200,831. Larner, C. W. July 14, 1922, [Convention date]. Valves controlled by pilot or relay valves.-A valve device of the type in which the valve plunger slides in an internal cylinder supported by ribs within an external casing so as to leave an annular passage-way, has fluid pressure means for moving the valve plunger controlled by a piston working in a cylinder situated outside the main casing, said cylinder having two pressure inlets and a third passage connected through a three way cock to pressure or exhaust. In the form shown in the Figure the movement of the plunger 7 to and from its seat 8 is controlled by a pilot valve 10 mounted in a hollow spindle 11 and adapted to engage alternately with seats 9 or 12 so as to admit or exhaust fluid pressure from the actuating chamber 16. The hollow spindle passes through a partition 13 into a chamber 15 open to conduit pressure through ports 17 and is formed with a rack 14 coupled by an idle pinion to a second rack 18<1> connected by a rod 21 to a piston 22 working in a cylinder 23. The top of the cylinder is connected to the main inlet by pipes 24, 25 controlled by a valve 28 and to the cutlet by a pipe controlled by a valve 33 adapted also to be connected to exhaust through a valve controlled connection 34. The lower part of the cylinder is connected to the inlet through a pipe 26 controlled by a valve 29 and through a pipe 27 controlled by a three-way cock 30 which may also be used to connect the lower part of the cylinder to the exhaust conduit 31. When closed the valve may be opened by opening valve 28 and connecting pipe 27 to exhaust, valves 29, 33, 34 being closed. By closing valves 28, 34, opening valves 29, 33 and connecting pipes 24 and 27, the device is set so as to close automatically in the event of an abnormal reduction of pressure in the outlet. The valve may be closed manually by closing valve 33 and opening the valve 34. The rate of closing is regulated by positioning the pipe 26 so that it is closed bv the initial movement of the piston and throttling the pipe 32 by the valve 33 or by connecting the pipe 32 to the cylinder at several points each separately throttled. The piston 22 may be actuated by a separate pressure fluid under separate control for example that of a centrifugal governor. Holes 35, 36 are provided in the cylinder and piston rod whereby a pin may be inserted to lock the valve in its closed position. In a modification the rack 14 is formed on the upper side of the rod 11 and the connections to the actuating cylinder reversed. In a further modification the piston is secured to a prolongation of the rod 11 and the chamber 15 is dispensed with.