Patent GB-136351-A (GB)
Title: Improvements in and relating to Plansifters.
Inventor: PETER JACOB
IPC: B07B1/38
Filed: 1919-01-27
Abstract: 136,351. Peter, J. Jan. 27, 1919 Sieves with compound or variable motion.- In a plansifter of the kind comprising a series of sieves stacked one on top of the other, means for cleaning the sieves, and a sifting-channel in each sieve of the series, inner and outer vertical passageways are formed extending through the whole series of sieves inside and outside the sifting-channels, and means are provided whereby the stock discharged by the separate sieves and the products passing through their screens may be led to the separate vertical passageways according to any predetermined plan. In the form shown in Figs. 1 and 2, square sieves are used, and the inner passageways 7<1> are formed by radial partitions 7 within a circular partition 5 in the centre of each sieve frame 3. The outer passageways are formed by partitions 8 across the corners of the frames. The frames 3 are provided at their corners with reinforcing-members 4 which are staggered vertically, as shown in Fig. 4, in order that the sieves may be secured accurately in their correct positions between the bottom 1 and cover 2. Each frame carries a collecting-tray 10 mounted on ledges 11 above a transverse member 6. The woven screens 14 are fixed to the bottom of the frames, and partitions 9 mounted on the lower sides of the members 6 form sifting- channels of substantially spiral shape communicating through openings 15 with one or other of the inner passageways 7'. By rotating any of the sieves through an angle of 90, 180, or 270 degrees, it can be placed in communication with any of the passages, according to requirements. The partitions 8 are provided with removable slides 21 whereby any of the collecting-trays or sifting-channels may be placed in communication with the outer passageways. Brushes 12, mounted on arms carried by rings 13 surrounding the partition 5, are placed on each collecting-tray, except the uppermost. The .stock is fed on to the uppermost tray through an inlet 17 and passes through holes 22 on to the first sieve. The discharge from the inner passageways passes through horizontal passages 18 in the bottom of the plansifter to outlets 19, and that from the cuter passageways is collected at outlets 20. Obstructions 23, Fig. 1, or 24, Fig. 4, may be placed in the inner or outer passageways in order to divert the stock passing through the plansifter as required. Palettes 16 are placed inside or outside the partitions 9, according to the direction in which the stock is circulating through the sifting-channels. The application of the invention to a plansifter for bolting the stocks supplied from several reducing-machines is shown in Figs. 9 and 10. In this form, additional outer passageways 36 are formed by partitions 34, extending between the corner partitions 8, and by partitions 35 extending between the partitions 34 and the outer walls of the sieve frames 3. Slides 37 are provided in the partitions 34 in order that the vertical passageways may be placed in communication with any of the collecting-trays or sifting- channels as required. Inlet openings 32 are placed in each corner of the plansifter, the stock being diverted to the required sieves of the series by obstructions placed in the corner passageways. The plansifter is suspended from rods 31', and is driven from a pulley 30 by of an eccentrically-mounted shaft 26 extending through the centre of the plansifter. Balance weights 31 are mounted on the shaft 26 or on short hollow shafts secured to the shaft 26. The shape of the sifting- channel may be varied by changing the partitions 9. and a wider sifting-channel may be used in the upper than in the lower sieves; or the width of the channel may decrease towards tho centre of the sieve. In another modification. Fig. 19. circular sieves are used.