Document KROwzRvvKyDRxQ1YGzeqJzpeN

r \ A r Elliott steam jet ejectors, by virtue of their I ability to attain and maintain high vacuum, or low absolute pressures, economically, are often used in new processes involving the use of vacuum. A recent application is in connection with the impregnation of wood with synthetic resin. This is a new and exciting development in the lumber in dustry. Wood treated with synthetic resins and heat-dried under pressure acquires a smooth, highly polished surface without sanding or polishing. .i 4 ejector vacuum used in Lumber Impregnation A dye may be added at the time of impregnation, found that the pH of the impregnating urea-di- giving permanent color without painting or stain methylolurea mixture was most important. ing. This makes possible a wide range of decorative It was definitely found that a vacuum of less than effects. 1 in. mercury absolute was preferable. There seems Bruce E. Anderson, vice-president of The Gavan to be a direct relationship between the degree of Company, Inc., and a charter member of Forest vacuum pulled on the wood in the treating chamber Products Research Society, recently made a report and the rapidity with which this wood is treated. on this development before the American Wood Vacuum in the range of 2 in. to 3 in. absolute is Preserving Association at Portland, Ore. Some of relatively unsatisfactory to a remarkable extent as the points brought out in his report are briefly compared with vacuum ranges under 1 in. absolute. listed here. Mr. Anderson started his work in 1944 The first small pilot plant used a small mechanical as a member of the staff of the engineering experi vacuum pump, but the second plant built in 1945 mental station of the Georgia School of Technology. used the Elliott ejector illustrated. This plant was I Upon completion of his work on the original pilot also provided with complete mechanical handling I plant, he joined The Gavan Company which is of fluids throughout and a battery of mixing tanks. devoted to the development, manufacture, and sale It was found that the process was actually one I of plastic impregnated wood. In the first small pilot plant, fundamental princi involving chemical change, rather than the simple mechanical impregnation of a liquid into the wood, ples were established such as optimum pressure, and the removal of water from the wood. temperature, vacuum, and timing. Presteaming of ^Conclusions reached from Mr. Anderson's experi the wood, for instance, was ruled out, and it was ments have indicated the possibilities and limita- 14 vsh CRIMDEBN00000341