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Chapter 23 



STOCK INLET 



STOCK OUTLET 



REFINING PLATES 



sf bcK flow] 



Figure 23-1 3. — Single-revolving-disk pump-through refiner. Arrows indicate stock flow. 

 With 24-inch disk driven by 200 hp at 514 to 900 rpm, pulp capacity is about 50 tons/ 

 day. With 32-inch disk, driven at 450 to 600 rpm by a 400 hp motor, pulp throughput is 

 rated at up to 100 tons/day. (Drawing and data from The Bauer Bros. Co.) 



Atmospheric disk refiners. — Green chips fed to disk refiners operated at 

 atmospheric pressure may receive no pre-treatment, they may be steamed or 

 soaked in water at atmospheric pressure and temperature, or they may be cooked 

 in steam or water at elevated pressures and temperatures. Hardwood chips 

 having no pretreatment produce a slow pulp, with a large proportion of broken 

 fibers and fiber bundles. Such hardwood pulp can be used in dry-process fiber- 

 board where lignin bonds between fibers do not significantly contribute to board 



