GB209558A - Improvements in or relating to valves - Google Patents

Abstract

209,558. Blakeborough, R. A., (Larner- Johnson Valve & Engineering Co.). Nov. 22, 1922. Fluid-actuated valves. - A stop or throttle valve, of the kind comprising a tapered plunger adapted to work in a cylinder arranged axially in a conduit having a contracted part with which the plunger engages, is provided with means arranged to close the valve in the event of the direction of flow being reversed and with mechanism adapted to arrest temporarily the movement of the plunger in the event of the conduit pressure rising abnormally high. The plunger 3 adapted to engage a seat 4 has a flexible packing collar 24 and works in a cylinder 2 supported by webs 5 from an outer casing 1. The nose of the plunger has a ported nipple 7 leading to an intermediate chamber 8 and controlled by an auxiliary valve 27 mounted on a tubular stem provided with ports 52 and with a non-return ball valve 16. Communication between the chamber 8 and the main actuating chamber 21 is established during the first part of the closing movement through slots 20 in a. sleeve 50 held stationary by a strut 51 and through a passage 15, chamber 19 and valve 22 controlled from outside the casing. As the valve nears its seat the slots 20 are cut off by the partition 9 and the closing movement retarded. In the form shown, on the tubular stem which telescopes over a fixed tube 17 leading to the chamber 19 is provided a rack adapted to be moved by a hand actuated pinion 13. In a modification this pinion is itself actuated by a forked rack operated by a screwed spindle.. To prevent water hammer a control valve 62 is arranged to control the flow between the chambers 19, 21. This valve is actuated against the action of a spring 58 by a floating lever 44 one end of which is connected by links and lever to the main plunger while a toothed rack 47 is suspended from the other end. In the event of abnormal pressures developing the rack 47 is locked in position by a pressure actuated catch 57, so that further movement of the main valve closes the valve 62 and thus arrests the movement of the main valve.