File:Pacific service magazine (1918) (14783092732).jpg

Identifier: pacificservicema1019paci (find matches)
Title: Pacific service magazine
Year: 1912 (1910s)
Authors: Pacific Gas and Electric Company
Subjects: Pacific Gas and Electric Company Electric utilities Electrical engineering Public utilities
Publisher: San Francisco : Pacific Gas and Electric Company
Contributing Library: San Francisco Public Library
Digitizing Sponsor: San Francisco Public Library

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the top of the retorts to thebottom was rarely more than 50 centi-grade degrees. It will thus be seen thata fairly even temperature was maintainedthroughout the whole retort chamber. This attainment of an even temperaturewas the deciding factor in utilizing thedowndraft system of heating rather thanan updraft system. The fruit pits, after having been fedinto the storage hoppers above the car-bonizing units by the belt conveyor sys-tem, fell by gravity into the retortchamber. When the carbonizing of thegreen material that originally was in thetubes was complete, as determined bywithdrawing some of the material, theprocess men w^ould operate the wormconveyors at the discharge end of theretorts by means of levers which weregeared up to the worm conveyor. Theusual schedule in operating these wormconveyors was to make one completerevolution every four minutes. At times,due to the unusual wetness of the pits orother variations in the class of raw ma-terial handled, this withdrawing schedule
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Inside storage pile of peach pits waiting to be used. Approximately 500 tons. 312 Pacific Service Magazine had to be varied. The following tableshows the relation between the dischargeschedule, the time of carbonization, theyield of charcoal produced and the totaltonnage per unit of four tubes each pertwenty-four hours: Minutes Duration of Production in per carbonization Per cent tons per unit revolution in hours yield per 24 hours 3 3.0 32.0 12.5 4 4.25 30.0 9.06 5.5 26.0 5.78 7.0 21.5 4.1 In discussion of the yield obtained itmust not be thought that a low yield in-dicated poor operation, unless that yielddropped below 20 per cent. At the oper-ating temperature established at thisplant, a yield of 20 per cent indicatedcomplete carbonization. A higher yield than that meant that thecharcoal still retained some volatile mate-rial, and the class of charcoal requiredfor gas defense purposes was one of abso-lute purity, i. e., almost chemically purecarbon. At the San Francisco plant, how-

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