

A Paper Pulp Operation in Wisconsin 63 



of butter and in this condition is called " stock." While the 

 machine is in operation a spray of water plays constantly on the . 

 wood to wash the pulp away and prevent damage by burning 

 due to friction. 



From the grinder room, the stock is conveyed to the press 

 room where it is first washed thoroughly and then run over the 

 couch rolls which dries it and presses the water out. These rolls 

 consist of hollow cylinders 7 feet long and 20 inches in diameter. 

 The outer part is made of hardwood covered with a layer of felt 

 about inch thick. There are seven of these rolls, three being 

 used for the stock from the sulphite process and four for the 

 ground wood stock. When taken off the roll by a " skinner" 

 (a pointed stick 30 inches long), the pulp looks like thin paste- 

 board. It is folded and taken to the beater room where it is 

 mixed with the sulphite stock. 



Sulphite Process 



The species used in this process are hemlock and a small 

 amount of balsam. After the log has been cut into 2 foot 

 lengths and rossed, it is conveyed to the " hog" where it is chiseled 

 into small chips ^ inch to 2 inches square. The chips are elevated 

 to bins from which they are taken to the digestor w r here they are 

 cooked with a compound of sulphurous acid which is manu- 

 factured at the plant. 



The chemicals used to manufacture the acid are sulphur, 

 limestone and w r ater. The sulphur in the solid form is shipped 

 from Louisiana costing $27.00 per long ton delivered at the mill. 

 In order for it to unite with the lime water, it must be in the 

 gaseous form, hence it is volatilized by burning. There are 

 four ovens each 10 feet long, 6 feet wide and 2 feet deep that are 

 used for this purpose. Sulphur in the powdered form is fed from 

 above into each oven once every hour, a strong draft being main- 

 tained to secure complete combustion. The fumes are con- 

 veyed through lead pipes to the acid tanks. The limestone is 

 shipped in from Mebashtock, Mich. Four acid tanks each 150 

 feet high, and 8 feet in diameter are required for the manufacture 

 of the acid. The tanks are made of 4 x 6 Norway pine and 

 creosoted. One roof covers the four tanks, one being built in 

 each corner of the tower which is divided into four compart- 

 ments. The tanks are charged once every week in the follow- 

 ing manner. An elevator carries limestone to each floor where 

 it is dumped in at the man hole. One compartment is filled at 

 a time. In order to keep the tanks full all the time, it requires 

 two men working 6 hours per day. When full water is turned 

 on from above. The sulphur fumes come in from the bottom 

 and are drawn up through the limestone and water by means of 



