GB914305A - Improvements relating to washing machines - Google Patents

Abstract

914,305. Washing-machines. WELTER, O. Jan. 13, 1959 [Jan. 20, 1958; Aug. 12, 1958], Nos. 1857/58 and 25946/58. Class 138 (2). [Also in Group XXIII] Washing is effected by a liquid stream on which are superimposed vibrations at a sonic frequency and at an ultrasonic frequency. In Fig. 1 the vibration generator comprises an impeller 4 rotated in a housing 19 by a motor 6. The impeller has vanes 16 whose axial and radial edges 20, 17 are closely spaced from the housing 19 and a rigid annular member 18. The impeller is made of a hard elastic material, e.g. bronze, gun-metal, chromium-steel, glass or ceramic, and vibrates axially at e.g. 18,000 c.p.s. with a node at the centre of the impeller. Liquid circulates through four slots 21 in the housing 19, through a perforated false wall 23 and through holes (not shown) in an annular member 14. The slots 21 are shaped to give a rotary component to the liquid stream (Fig. 2, not shown) and the washing container 2 is square in section. The housing may be detachably mounted on the member 18 by means of a bayonet joint. Figs. 3, 4 show a modification in which a single slot 21 extends around e.g. 180 degrees of the periphery of housing 19 and is located with its centre in the upper lefthand part of the housing when viewed as in Fig. 4. The strength of the washing action can then be varied by altering the direction of rotation of the impeller. The liquid is returned to the impeller 4 through a perforated false bottom 38 which may be covered by a filter. Air may be supplied through a pipe (not shown) connected to a bush 40. Forced highfrequency vibration of the impeller may be produced by providing a pattern of radial crests and troughs on the upper face of the impeller and a closely adjacent rigid ring secured inside the housing (Figs. 7 to 9, not shown). In a modification the crests and troughs may be formed on the member 18 and the edges 17 of the impeller vanes. The second Provisional Specification describes also a modification of the arrangement in Fig. 3 wherein a cylindrical sleeve is rotatably mounted between the impeller and housing. When the impeller is rotated in one direction apertures in the sleeve and housing are in alignment. If the direction of rotation is reversed the sleeve rotates through such an angle that the apertures are out of alignment, and the increased pressure produced within the housing is used to empty the container through a suitable connection.