GB278179A - Balanced stop valve device - Google Patents

Abstract

278,179. Cockburn,s, Ltd., and Mac- Nicoll, D. Oct. 6, 1926. Stop valves; closure members.-A stop valve device comprises oppositely movable coaxial lift valve members of equal area adapted to functionas pistons, pilot valves being provided to connect the spaces behind the pistons with that between the main valve members. The valve members 11, 12 which co-operate with seats 8 secured to a partition 5 by flanged rings 9 and studs 10 have skirts 13, 14 slidably fitted in cylindrical recesses 15, 16 formed in the covers 17, 18 and are carried by spindles 19, 20 having right and left-handed threaded parts 19<1>, 20<1>. The threaded parts of the spindles are engaged by elongated nuts 25, 26 secured to toothed wheels 39, 40 and supported by non-rotatable sleeves 33, 34 acted on by springs 31, 32 housed in casings 27, 28. The wheels 39, 40 are engaged by pinions 41, 42 on a common actuating shaft 43 provided with a hand-wheel 46. Rotation of the spindles 19, 20 is prevented by collars 49, 50 engaging guide surfaces 47, 48 on the covers 17, 18 and a nut 53 is fitted to the spindle 19<1> to limit the movement of the hand-wheel. Passages 54<1>, 55<1> leading to the recesses 15, 16 and a passage 66 leading to the space between the main valve members are controlled by a double faced lift valve 56 mounted on a screwed spindle 58 actuated by a non-reciprocating nut 62 and hand-wheel 63.. The double faced valve may be replaced by two separately actuated valves. According to the Provisional Specification, the pilot valves may be arranged to seat on the main valves which are actuated by levers connected together by a screwed operating spindle having threads of opposite hands. In a modification the pilot valves are arranged externally of the stop valve casing and are operated from connections with the actuating spindle. Non-return valves may be arranged between the cylindrical recesses and the inlet and outlet sides of the stop valve.