The kiln drying of lumber; a practical and theoretical treatise . Some spe-cies, such as the western firs, Alaska cedar, and yellowpine, are not seriously injured at this temperature, butthe majority of woods, including nearly all the hard-woods, will not stand it. Some of the conifers as west-ern red cedar {Thuja plicata) when heated above theboiling point are torn to pieces by the expansion of thesteam generated in the cells. Temperatures of 300° F.,or more, are in use with superheated steam, which isusually forced into the kiln by means of a blower. Theheat may be produced, however, by the
The kiln drying of lumber; a practical and theoretical treatise . Some spe-cies, such as the western firs, Alaska cedar, and yellowpine, are not seriously injured at this temperature, butthe majority of woods, including nearly all the hard-woods, will not stand it. Some of the conifers as west-ern red cedar {Thuja plicata) when heated above theboiling point are torn to pieces by the expansion of thesteam generated in the cells. Temperatures of 300° F.,or more, are in use with superheated steam, which isusually forced into the kiln by means of a blower. Theheat may be produced, however, by the heating pipeswithin the kiln itself. In the improved method recently developed for theForest Service * a remarkably low temperature ofsuperheat is made possible by producing a very highvelocity of the steam passing through the lumber. Thehigh velocity is produced within the kiln itself by meansof steam jets, and the superheating is accomplished bysteam heating pipes in the current of steam. Verysuccessful drying has been accomplished with a tem- * See page Fig. 47.—Recording thermometer record of temperature of kiln thermostatically controlled. DRYING BY SUPERHEATED STEAM 203 perature as low as 220° to 225° F. (See Table IV,page 50.) Application of New Method.—In applying thismethod, it can be readily combined with my spray-con-denser system, by the addition of the water sprays andthe pipe condensers in the spray chambers. By thiscombination, the drying may be hastened towards theend of the operation without necessitating an exces-
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Keywords: ., bookcentury1900, bookdecade1910, bookidkilndry, booksubjectlumber
