Patent GB-437856-A (GB)
Title: Improvements in water-softening apparatus of the base exchange type and in filters
IPC: C02F1/42
Filed: 1935-01-18
Abstract: 437,856. Softening water; filters; electric-motor control systems. UNITED WATER SOFTENERS, Ltd., Aldwych House, Aldwych, London. Jan. 18, 1935, No. 1729. Convention date, Jan. 27, 1934. [Class 46] [See also Group XXXVII] Each of a battery of base-exchange water-softening units has electricallyactuated automatic means for controlling the reconditioning cycle and the units are electrically connected so as to prevent overlapping of the reconditioning period of the units. The reconditioning of each unit may be controlled by a multi-way valve 3, Fig. 8, turned by an electric motor 21, which is stopped as the valve reaches the position corresponding to each of the reconditioning stages and started again after a period determined in the case of the backflushing and rinsing stages by a timing motor 66 and in the case of the brine-treatment stage when a pre-determined volume of brine has passed from a storage vessel 18 through the base-exchange material. The switch 51 of the motor 21 is operated by an electromagnet 100. The soft water passing to service from the valve 3 passes through a meter 7 which turns a shaft carrying cams 45, 46, and, when a definite amount of water has been treated, the cam 45 allows an arm 49 to drop and close contacts 50, the circuit of the electromagnet 100 between the terminal leads 52, 63 being completed to start the motor 21. The circuit is completed by a wire 54, a brush 55, a drum 56 on the valve spindle, an arm 57 rotating with the drum, an arcuate contact strip 58, a wire 59, contacts 50 and a wire 60. The motor 21 is stopped with the valve 3 in the back-flushing position when the arm 57 leaves the strip 58, the arm then engaging a similar strip 64 to complete the circuit of the timing motor 66. After a period determined by a cam 79 on the shaft of the motor 66 an arm 80 closes a contact 81 in a circuit comprising a contact strip 65 and the electro-magnet 100, so that the motor 2@ turns the valve to the brine-treatment position. After a further period of rest the magnet is again energized when a float 22 in the tank 18 falls sufficiently to close a switch 23. There follows a rinsing period which is timed by the motor 66 and the valve is finally returned to its initial position. The circuits for these later movements are completed through contact strips 86, 89, 90. The shaft of the cam 45 is re-set by a motor 67 in a circuit completed by the strip 64, the cam 46 breaking this circuit when the shaft has been turned into the correct position. A switch 53 enables an operator to cut out the automatic timing means and to energize the magnet 100 at will. Arrangements may be made for the timing motor 66 to be supplied from a source of current other than that from which the motor 21 is supplied. Provision is made for ensuring that only one unit shall be undergoing regeneration at any time by breaking the wire 59 of each unit at contact points which are closed by contact pieces on the arms 57 of the other units only when these arms are at rest between reconditioning periods. Alternatively, to ensure that re-conditioning in one unit shall start when that in another is finishing, only one of the units is provided with contacts 50 closed by the motor 7 and a switch in the circuit for energizing the magnets 100 in the other units at the beginning of each reconditioning is closed by a solenoid in a circuit comprising the arm 57 and the contact strip 90 of the preceding unit of the series. The outflow pipe for the treated water from each unit may be controlled by a valve regulated by a Venturi element in the pipe. As shown in Fig. 1, the valve 3 may have two connections 10, 20 to drain for use respectively during back-flushing and rinsing, each connection having its own flow-control device, 32, 33 which may be of the kind described in Specification 381,474, [Group XIII]. Both these connections are open during the brine treatment so that waste liquor may then flow away more freely. The valve has a connection through an injector 12 to the top of the treatment vessel 1 and the injector draws brine from the tank 18 to which it is supplied from a salt-dissolving tank 27. The liquid level in the tank 27 is kept constant by a float-controlled valve 30 in a vessel 29. The pipe 19 connecting the tank 18 and the injector and the pipe connecting the vessels 27, 18 are provided respectively with diaphragm valves 16, 17 to which water under pressure to open and close the valves respectively is directed through a small bore pipe 13 when water is being passed from the valve 3 through the injector 12. The invention includes the application of similar electric control in connection with a battery of filters which require periodic back-flushing and rinsing with or without treatment with a revivifying agent.