Patent GB-270461-A (GB)
Abstract: 270,461. Alliott, E. A., Hatfield, A. E., and Achille Serre, Ltd. March 20, 1926. Treating-materials; reagents, supplying. - In the treatment of soiled liquid from washing machines used in dry cleaning, laundry washing, wool scouring and like operations, absorbent porous materials or reagents to aid filtration are added to the liquid, as it passes to a filter, centrifugal separator, or other separating means, in quantities which vary as the washing operation proceeds in accordance with the amount of impurities in the liquid. The invention is specially applicable in connection with the process for treating dry-cleaning liquid described in Specification 266,850, [Class 91, Oils &c.], and in processes where the circulation is continuous from the washer to the filter and back to the washer. The filter aid in suspension or solution passes from a mixing tank to the pipe line, which supplies the soiled liquid to the filter, through a tank 6, Fig. 2, the discharge from which is regulated as desired, and preferably through a tank 7, Fig. 5, by which variations of suction in the washing tank are prevented from affecting the rate of discharge from the tank 6. A charge of filter aid enters the tank 6 through a pipe 27 and is discharged through an aperture in a shield 19 surrounding a vertical extension 17 of the outlet pipe 18 and through a corresponding slot in the extension. The tank is provided with agitating arms 14 and blades 16 fixed to rotating funnels 15. -The discharge of the filter aid is at first almost uniform, the only variation being that due to the liquid head. The fall of a float 26 opens by means of a relay 25 a valve through which a supply of the soiled liquid or of clean liquid containing no filter aid is admitted to the tank. The concentration of the filter aid in the liquid leaving the tank 6 is subsequently continuously lowered, the amount of filter aid supplied to the pipe line leading to the filter being correspondingly reduced. Fig. 4 shows a modified form of outlet in which the shield surrounding the extension has apertures 34. 35, 36 at different levels and there is a reduction in the discharge of filter aid as the liquid level falls first below the aperture 34 and then below the aperture 35. In each form pipes 28 are provided for flushing purposes. Modified apparatus, which may replace that shown in Fig. 2, is shown in Fig. 7. The discharge is through a swivelling pipe 92 which is lowered uniformly or at a decreasing speed by a rope 94 connected to a release-drum 97. As the pipe reaches its lowest position a trip block 96 on the rope opens a valve to supply liquid to the tank which lowers the concentration of the filter aid discharged therefrom. The filter aid from the tank 6 is passed through a pipe 39, Fig. 5, funnel 40, pipe 41, under a cover 42, and through a valve 44 to a pipe 43 and the filter supply pipe. The liquid under the cover is in free communication with that in the surrounding chamber 7 and the valve 44 is controlled by a float 50 connected to a counterweight 58 and a dashpot 60. The process may also be carried into effect by providing a tank fitted with agitating means and preferably of larger capacity than the washer, in the pipe line between the washer and the filter, and supplying a charge of filter aid to this tank at the commencement of each washing operation. The amount of filter aid carried forward to the filter will diminish as each washing operation proceeds. Alternatively, the filter aid may be supplied to the washer itself.