File:The manufacture of pulp and paper - a textbook of modern pulp and paper mill practice (1921) (14781765231).jpg

Identifier: manufactureofpul03join (find matches)
Title: The manufacture of pulp and paper : a textbook of modern pulp and paper mill practice
Year: 1921 (1920s)
Authors: Joint Textbook Committee of the Paper Industry Stephenson, J. Newell
Subjects: Papermaking Wood-pulp
Publisher: New York : McGraw-Hill Book Company
Contributing Library: NCSU Libraries
Digitizing Sponsor: NCSU Libraries

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g an angle of 45° with the axis, thusmaking the total angle of the cone 90°. A cast-steel neck H isriveted or welded to the top end, to which a cover J is bolted witheasily-removed, swing bolts K. The digester is charged throughthis opening. At the bottom of the digester, is an outlet F,about 6 in. in diameter, for the discharge of the pulp. Thetrunnions L, which support the digester and around which itrevolves, rest in strong bearings M, supported on a rigid founda-tion N. The steam pipe D is continued up the inside of thedigester, and is connected up with a perforated steam coil 0,placed as high as possible and supported on the shell. The totalarea of the perforations in the coil should be equal to the areaof the cross section of the pipe. It is important to protect allparts of the digester from the wearing effects of the rushingsteam, which are considerable and may cause an accident;therefore, the perforations should be so drilled that the steam §6 THE DIGESTER ROOM 25 m- i- or;
Text Appearing After Image:
Fig. 4. 26 MANUFACTURE OF SULPHATE PULP §6 will not impinge directly on the shell. The cock E, which servesthe double purpose of sampling valve and as relief valve for airand turpentine in the early stages of the cook, is supplied with anipple for connection with a steam hose attached to a pipe line,to carry the gas outside the digester room. This cock is locatednear the bottom of the digester, to make certain that no liquorwill be pulled out when air, etc., are gassed off. It is then at theuppermost position, the digester being in a reversed positionfrom that shown in the figure. The digester makes a revolution in from 8 to 12 minutes, theturning being effected by a worm-gear arrangement W, which iseither directly connected to a motor or is belt driven. The jointsin the trunnions must be watched for leaks, and must be re-packedfrequently. 34. The strong features of the rotary digester are perfectcirculation, which gives a uniform grade of pulp, and the betterheat economy. The saving

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