GB234520A - Improvements relating to the comminuting and mixing of substances of all kinds - Google Patents

Abstract

234,520. Hildebrandt, H. May 26, 1924, [Convention date]. Ball and like mills and apparatus. - In comminuting materials, the comminuting means together with the material to be treated is moved constantly in a continuous stream by centrifugal action over a movable and a stationary grinding-track of an enclosed operating chamber through guide passages. Deep shells with steep upwardly and outwardly rising walls, preferably conical, are used for imparting the rotary and centrifugal movement to the comminuting means and material, and after projection against the grinding-track, the loose balls and material are returned directly or over a stationary guide-body, suspended in the rotary shell, downwardly to the middle of the shell. The apparatus can be used for mixing substances, and for obtaining substances of colloidal fineness. As shown in Fig. 1, a rotary vertical shaft 1 carries a deep shell 2, which is open at the top and closed at the bottom, and a number of similar inner shells which are open at the top - and bottom and equally spaced so as to form guiding and pressure chambers 5 between them, the inner shells being preferably secured to the outer shell by means of distance-pieces and securing elements. A stationary guide-body 4 with its lower wall similar to the adjacent wall of the shell 2 is secured centrally to the casing cover 15 and supplied with heating or cooling liquid through a central member 14 and ribs 13. In operation, the balls 7 and the material pass upwardly through the chambers 5 to the grinding- chamber 6 enclosed by the stationary grinding- track 3, and fall on the upper wall of the guiding- body 4 whence they return by the central opening 8 to the lowest part of the shell 2. An adjustable wedge-ring 10 closes the annular slot 9 between the shell 2 and the track 3, and any material that enters the slot is blown back by air currents produced by a ring 11 of blades secured to the outside of the shell. A charging opening 16 and an opening 17 through which the finest material can be withdrawn are provided in the cover 15. The fine material is withdrawn from the bottom of the shell through a central opening which is opened and closed by an axiallymovable plunger 18 operated by a spindle 19 and gearing 20. The material passes through the aperture between the plunger 18 and a packing- plate 21 into a discharge chamber 23 and thence by holes 24 into a chamber 25. The plunger may be pressed against the plate 21 by springs, and the plate 21, Fig. 2, may have longitudinal slots 22 which are closed bv raised portions on the plunger 18. In a modification with a single guiding-chamber, guide-ribs are provided on the track and the guide-body, the ribs being either transverse or at an angle to the direction of movement of the balls. In Fig. 6, the triangular slot 9 extends upwardly and the heating &c. liquid is supplied to the rotating shell-wall by a nozzle ring 27 and discharged through an opening 29, while the inlet opening 16 and upper outflow opening 17 are arranged centrally. In another arrangement, the guide-body is provided on its side towards the shell with vertical or inclined guide bars or ribs extending up to the shell so that the balls receive a rolling movement when passing up the shell. Projecting ribs may be. provided on the grinding-track and may be in. tegral with the track or formed as separate hollow parts and arranged to be heated' or cooled. In the device shown in Fig. 10, the grinding is effected mainly by impact the balls and material after beating on the track 3 passing downwardly outside the rotary shell 2 into a surrounding stationary casing shell 33 and being guided by a body 34 to the lower opening of the shell 2. The open-ended shell 2 is secured by distance-pieces and securing elements 32 to the shaft 1, and the guide-body 34 is combined with the discharge plunger. A protecting shell 36 is suspended and secured in the larger casing shell, and any material that may enter the chamber 39 between the rotary shell 2 and the shell 36 is moved upwardly by fan blades carried by the shell 2.