Patent GB-321757-A (GB)
Title: Improvements in or relating to apparatus for treating liquids
IPC: C02F1/42
Filed: 1928-09-04
Abstract: 321,757. Electrolux, Ltd., (Aktiebolaget Filtrum). Sept. 4, 1928. Purifying liquids.- In apparatus for treating liquids by the base-exchange method in which there is a servomotor tripped by a water meter, or the like, to control the steps of the treating and regenerating processes once the servometer is released, the rate of its movement in each direction is controlled directly or indirectly by itself. The supply of energy to the servomotor is increased by movement of the servomotor in one direction and reduced, or cut off, bv movement in the opposite direction. A member connected with the servomotor is provided controlling the position of an auxiliary valve regulating the discharge of the servomotor thereby regulating automatically the duration of each step of the regenerating process in accordance with said valve positions. Base exchange material is located in container A, Fig. 1, and regenerating material such as salt in vessel B. A main valve C controls the various stems in the process. A servomotor D operates the valve C, E representing a water meter or equivalent. Hard water enters by the conduit 10 and soft leaves by conduit 11. The valve C is connected to the top of the container A by a pipe 12 and to the bottom by a pipe 13. The waste pipe is shown at 14 and connecting pipes at 15, 16. The operation is as follows. When a predetermined amount of water has passed the meter E, a cam disc 28 releases a pin 32 and allows a spring 31 to pull down a lever 29. This trips a catch 37 on a lever 38 pivoted at 39 to a spindle carrying a cam 41, Fig. 5, thereby opening a valve 43 to main water pressure in pipe 47 attached to conduit 10. Water then passes through channels 48 and pipe 25 to underside of servomotor D forcing up the piston. A piston rod 23, Fig. 3, is connected by chain 58 .and pawl 59 to a disc 65 on the main valve spindle, and rotates it through 90‹. During the first upward movement of the piston rod 23, a pin 71 on the lever 38 is engaged by an outer guide surface 69 on the rod 23 which presses the lever 38 still more to the right, Fig. 3, rotating the spindle 39 and increasing the opening of the valve 43 and accelerating the upward movement of the rod 23. The valve 43 is maintained full open during subsequent upward movement of piston rod by the pin 68 riding over the peripheral surface of control disc 66 until the pin iS forced into recess 67 by a spring 40, Fig. 4. The lever 38 then moves to left, allowing valve 43 to close against main water pressure. During the rotation of the valve spindle, a recessed disc 55 on the valve spindle rotates with the end of a lever arm 54 bearing against it until a spring 57 causes it to enter a recess 55<1> the depth of which determines the position of a valve 51, Fig. 6, in the discharge pipe 50 of the servomotor. The piston rod 23 is moved down by a weight 24, Fig. 3, and by a spring 63 through a drum 61 and chain 58. Water beneath the piston 22 runs to waste-pipe 14 by channels 25, 48, 49, 53 and 50. The rate of discharge is determined by the position of the lever arm 54 and valve 51. During this downward movement of the piston 23, backflushing occurs and hard water can be obtained by the service pipe 11. At this time, the valve 43 is maintained in its closed position by the pin 71 of the lever 38 riding against the inner surface 70 on the rod 23. At the lowest position of the rod 23, the pin 71 is forced by a surface 77 on pivot plate 74 through the aperture 73, Fig. 4, in a guide 72 moving the lever 38 and spindle 39 to the right, opening the valve 43 so as to move up the piston 22 again. The main valve is thus set for the salting. Hard water can be drawn from the service pipe by way of pipe 20. During the next downward movement of the servomotor, the valve is set for washing, hard water being obtainable by the service pipe. When the rod 23 moves up for the fourth time, the valve is set for softening, soft water being obtainable by pipe 11. When the piston rod 23 is reaching its lowest position, the action of the pivot plate to move the pin 71 to the right, Fig. 3, is prevented by a stop 78, Fig. 4, on disc 66 which moves to abut against the upper end of the plate. The lever 38 does not move and the softening process continues. The water meter is thereby actuated and the lever 29 is reset. A modification of the cut-off and auxiliary valves is shown in Figs. 12, 13. Movement of the lever 38 and spindle 39 displaces a needle valve 114 and allows main water to pass to underside of servomotor as before. When the piston has reached its highest position, the lever 38 by the pin 68 rests within one or other of recesses of the control disc 66, the depth of the recess controlling the position of the valve 114. On the downward movement of the piston, the water in the servomotor is forced through pipe 25, chamber 112, cock 113 and channel 116 to waste 14. Cock 113 is adjusted finally according to pressure of main supply so as to allow passage of water from servomotor at a predetermined rate. Specification 293,033 is referred to.