Chemistry of pulp and paper making . Fig. 31. Three-pocket Grinder(i) Grindstone (2) Shaft (3) Steel flanges (4) Casings or side frames(s) Bridge-trees (6) Studs to support (7) Pockets (8) Hydraulic cylin-ders (9) Piston rods (10) Pressure foot in Fig. 33 is of this type. The advantages of this grinder aresaid to be (i) increased capacity, (2) charging is automatic andnot subject to the irregularities of manual feeding, (3) constantload on motor or turbine and (4) decreased cost of pulp coming away from the stones collects in pits underthe grinders and from these pits it flows t
Chemistry of pulp and paper making . Fig. 31. Three-pocket Grinder(i) Grindstone (2) Shaft (3) Steel flanges (4) Casings or side frames(s) Bridge-trees (6) Studs to support (7) Pockets (8) Hydraulic cylin-ders (9) Piston rods (10) Pressure foot in Fig. 33 is of this type. The advantages of this grinder aresaid to be (i) increased capacity, (2) charging is automatic andnot subject to the irregularities of manual feeding, (3) constantload on motor or turbine and (4) decreased cost of pulp coming away from the stones collects in pits underthe grinders and from these pits it flows to screens with one-fourth to three-fourths inch perforations which remove slabs,knots, large sphnters, etc. For satisfactory operation of these 214 GROUND WOOD OR MECHANICAL PULP screens the stock should be diluted to at least i per cent drymatter. The stock passing these coarse screens goes next tothe regular screens of centrifugal or diaphragm type, and forthis operation it should be still further diluted to about Fig. 32. Three-pocket Grinder Sectional Elevation per cent dry. It is desirable that the diluted stock be passedthrough a riffler or over a sand settler before going to the screensas much wear on the latter is thus avoided. The screenedstock is then thickened to the proper consistency for use in thebeaters by means of filters, wet machines, or some other equiva- GROUND WOOD OR MECHANICAL PULP 215 lent device, or if it is to be sold in the form of laps these aremade on a wet press. The chief factors which enter into the production of mechani-cal pulp from any species of wood are: (i) Surface of stone; whether rough or smooth, sharp or dull,or of coarse or fine grit. SuBpension I^in for swinging magazine out to harg stone \, Charging Floor
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Keywords: ., bookcentury1900, bookdecade1920, bookpublishernewyo, bookyear1920
