File:The Street railway journal (1907) (14757832894).jpg

Identifier: streetrailwayjo301907newy (find matches)
Title: The Street railway journal
Year: 1884 (1880s)
Authors:
Subjects: Street-railroads Electric railroads Transportation
Publisher: New York : McGraw Pub. Co.
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Smithsonian Libraries

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ature of the liquid is raised and maintained between 100and no degs. C. for several hours—three to six hours gen-erally for seasoned wood, depending on its character andcondition. We know that air occupies as high as 60 per cent of thebulk of seasoned wood. According to the familiar law ofphysics, air expands 1/273 its volume for every degree C.that it is heated. Consequently when we heat the timber inthe preservative from about 20 degs. C. to slightly above100 degs. C, the air in the wood expands about one-thirdin volume and, in forcing its way out of the wood, expelsmuch of the moisture from the cell walls. This air risesto the surface of the hot preservative in the form of smallbubbles and the moisture leaves the oil in the form ofvapor. Given a high-grade preservative, carefully applied bythis simple method to wood that has been allowed some timeto season, an increased life many times greater than thecost of treatment is positively assured. ROYAL COMMISSION OF GERMANY AT SPOKANE
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MEMBERS AND ESCORTS OF THE ROYAL COMMISSION After the timber has been heated a sufficient length oftime the heat is shut off and the preservative is allowed tocool, or, better still, the timber is taken out of the hot pre-servative and submerged immediately in a tank of coldpreservative. The air still in the wood now rapidly con-tracts and tends to form a vacuum, which draws in thepreservative with considerable force, securing deep andthorough penetration. The depth of this penetration can,to a degree, be regulated by the length of time the timber isallowed to remain in the cold preservative. A lateral pene-tration of half an inch may be obtained in poles by thismethod. For timbers too large to be transferred during treatmentthe plant should consist of a treating tank, a supply tankand a receiving tank. This equipment will make it possibleto shorten the treatment by running out the hot liquid intothe receiving tank and admitting the cold liquid simultane-ously from the supply tank. Th

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