Patent GB-190519214-A (GB)
Title: Process and System of Purifying Water.
Inventor: WIXFORD JOHN FREDERICK
Filed: 1905-09-22
Granted: 1906-11-22
Abstract: 19,214. Wixford, J. F. June 26, [date applied for under Patents Act, 1901]. Liquids, sterilizing.-Water is purified and sterilized by converting dissolved carbonates into insoluble compounds in the presence of a coagulent. As described below, ferrous sulphate and lime are the reagents used. but the ferrous sulphate may be replaced by other salts of iron or by other sulphates, e.g. sulphates of copper, zinc, manganese, and aluminium. Water is drawn from a river or other source, Fig. 1, by pumps 4, and fed into delivery wells 7,8, in which it is agitated with ferrous-sulphate solution and milk of lime drawn respectively from digesters 15, 17. The required proportions of reagents are obtained by passing constant streams of liquid through the dige-ters, into which measured quantities of the solids are placed at regular intervals. Ferrous bicarbonate and normal carbonates are formed, and a coagulating action is exerted upon suspended particles of clay. The discharges from the wells react as they flow through a conduit 11 communicating with a settling-basin 12, in which the ferrous and ferric hydrates produced precipitate, carrying down the lighter insoluble impurities. The method of operation may be modified, the reagents being added to the same stream, the sulphate preferably before the lime. The proportions of reagents used vary according to the nature of the water treated. Suggested proportions are one grain of ferrous sulphate crystals and six grains of hydrate of lime per gallon of water. Or about eight times as much lime may be used as is required to satisfy the sulphate added. Or the lime may be approximately equal in quantity to that required to make the raw water alkaline. Excess of lime is indicated by the addition of silver nitrate or phenolpthalein, and can be measured by neutralizing with sulphuric acid. The Specification in the original form as published under the Act of 1901 comprises also additional description with regard to the chemical used, the settling-basin, and the apparatus in which the solutions are made. Ferrous sulphate may be replaced by fluorides, those of manganese, copper, zinc, iron, and silicon, and the silico-fluoride of iron, being mentioned. The fluoride of silicon, being an insoluble gas, is, when used, introduced through a lead or aluminium pipe immersed in a mercury bath below the surface of the water. The settling-basin is shown in Fig. 2. The water enters from the conduit 11 through vertical pipes 20 extending across the breadth of the tank. Sediment collects in depressions 21 of conical or pyramidal form, and is discharged to a sewer or river through pipes 22. To secure uniformity of flow, a baffle 25. consisting of a perforated partition or of parallel boards with intervening slits, extends across the tank in front of the outlet. The tank 15 is shown in Fig. 4. Ferrous sulphate in crystals is placed in the tank at intervals, and is dissolved by water issuing in horizontal jets from a number of nozzles 30 ; the solution passes by the pipe 32 to the wall 7. Fig. 8 shows the digester 17. Hot water is introduced through the pipe 16, and the milk of lime leaves by the pipe 49. The mixer is provided with curved blades 47 carried by a bar 44 secured by plates to a shaft 36. The shaft is journaled in bearings 34, 35, the latter of these being carried by a frame 33 which runs across the tank. A horizontal shaft 39 is journaled in bearings on the frame 33, and carries a bevel-wheel 38 gearing with the bevel-wheel 37 carried by the shaft 36. This subject-matter does not appear in the Complete Specification as accepted. [Reference has been directed under Patents Act, 1902, to Specifications No. 3550, A.D. 1869, and No. 2659, A.D. 1871, [Abridgment Class Sewage &c.], and No. 3593, A.D. 1884, No. 6459, A.D. 1885, No. 22,546. A.D. 1891, and Nos. 12,861 and 18,266, A.D. 1900, [Abridgment Class Filtering &c.].]