GB693601A - - Google Patents

Abstract

693,601. Filters; fitter media; purifying water. QUINN, D. H. May 22, 1951 [May 26, 1950], No. 11938/51. Class 46 A portable water filter comprises a flexible liquid container connected by a flexible tube to a filter housing containing filtr a t i o n means. The filtration means may consist of paper comprising between 10 and 40 per cent asbestos fibres which may be impregnated with a bactericide. An adsorptive agent such as an ion-exchange material may be included. Water to be filtered passes outwards from a bag 1a for effecting preliminary filtration into a flexible container 1. Fig. 1. and thence down a flexible tube 2 to a series of small inlet ports 10 in an upper part 3 of a filter housing. The water is distributed laterally in the housing by a mesh screen 8 and then passes through a disc 6 of the paper filter medium clamped between ridges 7 on the upper member 3 and a lower part 4 of the housing screwed thereinto. The filtrate issues from a series of outlet ports 11 in the lower part 4 into the screwed nozzle 5 of a water bottle. The disc 6 preferably is impregnated with a bactericide such as silver chloride; the bag 1a may also be so impregnated. The filter disc may be permeated with an adsorptive agent such as fine granules of activated carbon or with granules of anion- or cationexchange resins, or such agents may be retained in a layer or layers between two or more layers of filtering material. The parts of the filter housing may be made of a transparent plastic material such as polystyrene. In order to ensure that particles of impurities are not forced through the filter by the application of excessive pressure the water in the container 1 should initially be not more than 2 feet above the filter. As the filter disc becomes clogged increased pressure is obtained by raising the container to a higher level at each filling of the container until it is vertically above the filter. In the modification of Fig. 3 the upper part 14 of the filter housing comprises an internally threaded circular recess to receive a disc member 19 having finger holes 20 and a central hole suitably tapered to conform with an externallytapered inlet nozzle 15 for clamping the tube 18. Each of the mesh discs 23 is secured to its respective part of the filter housing by a press-button fastener 24, the neck of which fits loosely in the housing part so that the discs 23 remain stationary with, and thus do not abrade, the filter disc 6 whilst the parts 24, 25 are being screwed together. An internally-screwed bore 27 is provided to receive the nozzle of a water bottle as before; a drip ring 29 prevents water from dripping over the outside of the nozzle. Ridges 30 prevent unfiltered water from coming into contact with the nozzle.