GB468083A - Improvements in flushing valves - Google Patents

Abstract

468,083. Slow - closing valves. ELDER, D. Feb. 5, 1936, No. 3486. [Class 135] [Also in Group XXXII] A flushing valve g, Fig. 1, is lifted from its seat formed on the valve casing a by an unobstructed tubular member or sleeve n which is immediately returned to its inoperative position when the operating handle k is released, the flushing fluid passing through the member n whilst the closing of the valve is retarded by a dashpot d containing a body of fluid isolated from the flushing fluid. The valve g is connected to the dashport plunger f by a stem f passing through a gland i. The sleeve n is actuated by a crank-pin m controlled by the handle k which may have a return spring l. The upward movement of the plunger f is unimpeded due to the opening of a non-return valve o controlling passages o<1>, but is limited by an adjustable screw p mounted in a cover d and concealed by a removable cap q. This screw controls the duration of the flush. The rate at which liquid leaks back into the cap d depends on the clearance o<2> between the plunger f and its cylinder. A pawl r mounted on the sleeve n is held in engagement with one of the ratchet teeth r<1> to prevent a second actuation of the sleeve n before the flushing cycle is completed. A spring-loaded pawl which is held out of engagement with the teeth by an annular recess in the valve face until the sleeve leaves the valve is also shown. The plunger f may be of rubber or leather. Fig. 4, however, shows a metal plunger in which the clearance o<2> is controlled by a dished plate f<2> expanded by a screw p<1> which controls the duration of the flush. In the modification shown in Fig. 6, the plunger fits without clearance in its cylinder, the timing of the flush being controlled by an adjustable screw s<1> which more or less closes openings s<1>. The dashpot cylinder is isolated by a flexible diaphragm s and may contain oil, glycerine, water etc. Any leakage past the valve is shown by a tell-tale pipe t. During the flushing operation any water which has collected in the annular space between the sleeve n and the valve casing a is removed by a syphon pipe t<1>. The inlet b may be shut off after the flushing operation either manually or automatically by a valve-t<2>. In another form, the valve o is replaced by a spring-loaded ball valve and the timing is controlled by a pivotally mounted needle valve. In place of the needle valve a threaded member with a fixed orifice may be used. The valve g may have an additional cup leather below its face h. A spring- loaded detent may be provided to engage notches between the crank-pin m and the handle k so that definite fractions of the full flush are obtained according to the notch engaged. Specification 441,685 is referred to.