Patent GB-744265-A (GB)
Title: Method and apparatus for treating water
Inventor: BRIGGS ROBERT ERNEST
IPC: C02F1/48
Filed: 1953-06-30
Abstract: 744,265. Electrolytic treatment of boiler water. CLAYTON MANUFACTURING CO. June 30, 1953, No. 18084/53. Class 41. A process of treating boiler water comprises introducing raw water containing soluble scale-producing materials into the cathode compartment of a two-compartment cell divided by a porous diaphragm, together with highly alkaline concentrated boiler water, the resulting mixture of waters forming the catholyte, electrolytically treating the catholyte to increase the alkalinity thereof and so precipitate compounds of the scale-producing material, separating treated water from the precipitate, and utilizing the separated treated water, which contains soluble alkaline compounds, as boiler feed water, whereby the alkaline compounds are concentrated in the boiler feed water by evaporation of water to produce concentrated boiler water for introduction into the cathode compartment. Raw water is introduced by a pipe 46 (Fig. 1), having a solenoid operated valve 47 and a float valve 48 and mixes with heated concentrated boiler water, entering by a pipe 62, in a mixing compartment 14. The mixture then flows through an aperture 49 into a cathode compartment 16 containing a structure 51 comprising an insulating frame containing anodes 56 (see Fig. 3) and enclosed by canvas diaphragms 53 outside of which are iron wire screen cathodes 84. Some liquid enters the anode compartment 54 through an aperture 63 to form anolyte. When current is passed between the anodes and cathodes the water in the cathode compartment becomes alkaline and precipitates scale-forming compounds, mainly magnesium and calcium compounds with some silica, iron and manganese, while the anolyte becomes acidic and is discharged through a pipe 64 having a valve 65 adjusted to maintain the pH of the waste anolyte at above 1.5. The treated water flows from the cathode compartment 16 through an aperture 57 into a settling compartment 17, thence to a boiler feed compartment 18, and then on to a boiler 11 through pipes 71 and 23 by means of a pump 24. A steam and water mixture is discharged from boiler 11 through a pipe 32, provided with a solenoid-operated surge valve 34, into an accumulator 12. Steam is delivered from accumulator 12 to a load 19 by a pipe 41. A substantial portion of concentrated boiler water is recirculated from accumulator 12 through a pipe 42a by a pump 42b, to the boiler 11, the water level in the accumulator being kept constant by overflow through a pipe 44 to boiler feed compartment 18. Hot concentrated boiler water passes from accumulator 12 through pipes 61 and 62 to mixing compartment 14, under control of a thermostatic valve 59 actuated by a thermostatic member 58 to maintain the temperature of the catholyte at the desired level. Float valve 48 controls the intake of raw water as make-up into the system. When demand for steam drops, pressure building up in accumulator 12 operates a relay 77 which opens contacts 76, discontinuing power supply to the electrodes, de-energizing the solenoids of valves 47, 34 and a solenoidoperated fuel valve 31a, de-energizing an ignition device 31b, and stops a motor 27 operating pumps 24, 42b and a blower 26. Part of the precipitate formed enters the anode compartment 54, being dissolved in the acid anolyte and discharged through pipe 64, and part settles in the cathode compartment 16 and settling tank 17, being discharged periodically through pipes 67 and 68; any carried into supply compartment 18 may be discharged through a pipe 69. In a modification treated water flows over a weir from the cathode compartment and enters a separate settling tank, from which it flows to a separate boiler supply tank. In another modification a closed system is employed, operated at the pressure of the water mains supplying the feed water.