. The manufacture of pulp and paper : a textbook of modern pulp and paper mill practice. of pressure, though not absolutelyessential, should be performed if for no other reason than tosave the diffuser bottoms and to prevent blowing over so muchstock out of the diffuser. If the relief steam be let into a con-denser (Art. 43), the heat of condensation can be used for thepurpose of pre-heating water for different places in the mill. When the blowing pressure, about 80 lb., is reached, the diges-ter is revolved once more, to obtain a uniform mixture and to 28 MANUFACTURE OF SULPHATE PULP §6 facil
. The manufacture of pulp and paper : a textbook of modern pulp and paper mill practice. of pressure, though not absolutelyessential, should be performed if for no other reason than tosave the diffuser bottoms and to prevent blowing over so muchstock out of the diffuser. If the relief steam be let into a con-denser (Art. 43), the heat of condensation can be used for thepurpose of pre-heating water for different places in the mill. When the blowing pressure, about 80 lb., is reached, the diges-ter is revolved once more, to obtain a uniform mixture and to 28 MANUFACTURE OF SULPHATE PULP §6 facilitate the complete emptjing of the charge. When againin upright position, the digester is connected to a pipe line,through which its contents are discharged, on opening valve F,into the tank or diffuser that is used for this purpose. 36. Fig. 5 is a diagram showing the relation of the pressureto the time of cooking for a rotary digester which was relievedin 2 stages, and rotated between reliefs. The broken line, calledthe steaming curve, shows at a glance all the various steps just. r*—;—=—2 34050 1020304050 1020304050 1020304050 Pressure DiagramRotary Digester Fig. 5. described. It will be observed that at the end of about 15 min-utes, the pressure has reached about 42 or 43 pounds; during thistime the digester has completed 1| revolutions. The digesteris then stopped and received for about 10 minutes and the pres-sure falls slightly to 40 pounds. The digester is then revolvedand the steaming is continued until a pressure of 80 pounds isreached, which takes 15 minutes more and makes the totalelapsed time 40 minutes. The remaining steps are clearlyindicated on the diagram. The procedure illustrated in thediagram is a variation of the operation as described in Art. Stationary Digesters.—The equipment of the stationarydigester is very similar to that of the rotary digester, the chief §6 THE DIGESTER ROOM 29 difference being in the location of the various inlets a
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectpaperma, bookyear1921
