GB615821A - Improvements in and relating to apparatus for the treatment of water and other liquids - Google Patents

Abstract

615,821. Treating liquids. FROUDE, R. H. Aug. 12, 1946, No. 23805. [Class 46] Apparatus for the treatment of water or other liquids, for example, ion-exchange or filtering comprises in construction, a plurality of separate valves or other control means, a measuring device responsive, to a condition of the liquid and adapted to complete an electric circuit to start a time-control mechanism when the condition attains a predetermined value, a holding switch for the time-control mechanism in parallel with said electric circuit, and a switching mechanism driven by the time-control mechanism for operating the valves or other control means in correct sequence and timing to effect a predetermined cycle of operations, the holding switch being tripped in after the time-control mechanism has been running for a predetermined time, after which the valves or other control means are operated by the switching mechanism, and the holding switch being tripped out when the switching mechanism has completed its cycle, thereby stopping the time-control mechanism. In the arrangement shown a mercury manometer 14 is connected across the inlet and outlet pipes 2, 5, of a filter 1 by connectiogs 2a, 5a and a source of electric energy is connected to the mercury column 16. An adjustable contact 17 is arranged in the lowpressure limb 17 of the manometer so that when resistance to flow through the filter reaches a predetermined value the contact 17 engages the mercury column, and a circuit is completed through a time-control mechanism 19. The mechanism is in series with a holding switch 45 by means of which a drum 20 is driven after the time-control mechanism has been running for a predetermined time. The drum comprises seven discs each with a part made of conducting material for engagement by a spring finger, so that when a finger engages a conducting surface one of solenoids 36 to 42 is energized. Each solenoid controls a pilot valve (not shown) which in turn controls the operation of one or more valves 3, 4, 6, 9, 11, 12 or the motor 13 of an air blower, whereby the filter is subjected to the operations of draining, air scouring, backwashing and re-starting. Instead of contact strips for use in operating the valves, cams or like means may be used. Two or more units may be operated simultaneously by one control device. A delaying device such as a bi-metallic switch may be used in conjunction with the time-control mechanism.