Patent GB-482955-A (GB)
Title: Improvements relating to water treatment plant
IPC: D06F9/00
Filed: 1936-10-07
Abstract: 482,955. Softening water; filters. PERMUTIT CO., Ltd. Oct. 7, 1936, No. 27261. Convention date, Oct. 15, 1935. [Class 46] [Also in Group XXIX] A water-treatment plant including an apparatus that requires periodical reconditioning has a valve system for controlling the flow of water during normal operations and during reconditioning in which all valves are actuated by fluid pressure under the control of a common rotary multiple way control valve. Fig. 1 shows the invention applied to a downflow gravity water softener. The valve system comprises six main gate valves V<1>-V<5> each actuated by a double acting piston. The valve V<1> controls the supply of hard water, the valves V<2> and V<2>A which are opened together control the supply of hard water and the drain connection respectively during the back flushing operations, the valve V<3> controls the discharge of softened water, the valve V<4> controls a pipe connecting the discharge pipe to drain and the valve V<5> controls the supply of hard water to an injector 25 for introducing brine solution into the softener. All these valves are opened and closed in the required sequence by fluid pressure under the control of the manually actuated rotary disc valve shown in Figs. 2 and 4. This valve has a facing of hard rubber secured to a metal plate and has an arcuate recess adapted to connect the supply pipe in turn to an outer ring of ports B<1>-B<5> and an arcuate port O adapted to connect the pressure supply in turn with an inner ring of ports T<1>-T<5>. The lower face of the valve member is also provided with a recess or pocket roughly spiral in shape and adapted to connect the ports B<1>-B<5>, T<1>-T<5> to the exhaust pipe W as required. The valve is shown as being actuated by a hand wheel 40 but it may be automatically actuated through the medium of electrical or other apparatus under the control of water meters, time clocks or float controlled switches. The automatic control apparatus may be of the kind described in British Specification 437,856 or U.S.A. Specifications 1,937,325 and 2,012,194. Modifications are described showing the application of a rotary disc valve similar in design to that described as the control of an upflow water softener and to a filter. In applying the invention to a downflow pressure water softener the rotary disc valve is replaced by a rotary cylindrical valve or by the rotary plug valve shown in Fig. 15. In this cock pressure fluid is supplied to the chamber J above the larger end of the plug which chamber is connected by a longitudinal peripheral groove with peripheral recesses P<2>, P<4>. Complemental recesses communicate through a central passage W<3> with a chamber W<5> at the smaller end of the plug, which chamber is connected to drain. Where one main valve is being opened while another is being closed it may happen that both may be partly open at the same time causing a short circuiting of the fluid. To avoid this, the arrangement shown in Fig. 25 may be adopted and a further control valve 90 inserted in the conduit through which pressure is supplied to open the valve V<2>. This valve is actuated by a diaphragm subject to the pressure in the conduit B<3> through which pressure is exhausted while the valve V3 is closing. A restriction 91 in this conduit causes pressure to bank up on the conduit 92 while exhaust is flowing and so hold the valve closed. In modifications of this arrangement the valve 90 is actuated electromagnetically under the control of a pressure operated switch subject to pressure when one piston reaches its valve closed position or a switch mechanically connected to the piston. With plant of small size single acting diaphragms may replace one or more of the double acting pistons. Reference has been directed by the Comptroller to Specification 359,100, [Group XXIX].