GB241174A - Improvements in tube mills for grinding or crushing - Google Patents

Abstract

241,174. Wicking'sche Portland Cement und Wasserkalkwerke der Vorstand, (Assignees of Andreas, A.). Oct. 11, 1924, [Convention date]. Ball and like mills.-In a tube mill having two transfer spaces separated by a wall and sifting- devices between the coarse-grinding and the finegrinding chambers, the sieves are arranged radially in the sifting-space surrounding the transfer spaces, and the sifting-space communicates by openings with the transfer spaces for transferring the finely-ground material and at the same time conveying the coarsely-ground material back again. As shown, the wall e adjacent the coarsegrinding chamber a is provided with slits f and a central opening g, while the wall e adjacent the fine-grinding chamber b is provided only with a central opening g<1>. The transfer spaces c, d between the walls e, e' are divided by radial transverse walls h into a number of chambers i, and the annular sifting-space k surrounding the spaces c, d is subdivided by walls l and sieves m into chambers s, there being two chambers s for each chamber i. Openings n in front of the sieves, and openings o between the sieves or in front of the walls l, provide communication between the chambers i and the sifting-chambers s. T,he material passes from the chamber a through the slits f, chambers i of the space c, and openings n into the chambers s. The fine material falls through the sieves m into the adjacent chamber s and passes through the openings o into the chambers i of the space d, the guiding-member p conveying it through the opening g, into the chamber b. The coarser particles which have not passed through the sieve pass through the opening n back into the chamber i and are conveyed by the guiding-member p to the opening g of the chamber a. Some or all of the walls h, l and sieves m may be curved. Openings with tightclosing flaps z<1> are provided in the shell t of the sifting-space k to allow the sieves to be cleaned or removed. A plurality of partitions with transfer spaces and graded sifting-devices may be provided in the drum of the mill at suitable distances apart.