Direct Observation of the Tumbling of OSB Strands in an Industrial Scale Coil Blender

Authors

  • Gregory D. Smith

Keywords:

Blending, strand tumbling, furnish curtain, composites, OSB

Abstract

A series of experiments were carried out in an 11- by 35-ft industrial scale rotary drum blender in which a small amount of OSB furnish was placed, and the motions of strands were recorded with a video camera at various drum rotation speeds. As the blender rotated, the strands were lifted up by the flights—short fins inside and running the length of the blender—until they sloughed off and fell to the bottom of the drum. At low rotation speeds, the strands fell a short distance as they sloughed from flight to flight; at intermediate speeds, the strands fell across the diameter of the drum; and at higher speeds the freefall distance decreased again and was similar to the low speed case. The distance through which the strands fell with each revolution was shown theoretically to be inversely proportional to drum speed. The residence time of the stands in the blender set at a tilt angle of 3° was measured for five drum speeds and found to be directly proportional to drum speed. It was concluded that the speed that produces the most uniform dispersion of resin on the strands is a compromise between that which is high enough to ensure that the strands will slough from the flights many times, but low enough to provide sufficient time for the strand to twirl and flip and become coated with resin. The potential advantages of using specially shaped atomizer booms to direct strand flow to maximize the uniformity of the resin dispersion over the strand surface is also discussed.

References

Beattie, N. W. 1984. The Lignex spinning disc blender. In Proc. Washington State University Particleboard Symposium, Pullman, WA. 18:345-356.nCarroll, M. N., and D. McVey. 1962. An analysis of resin efficiency in particleboard. Forest Prod. J. 12(7):305-310.nChristensen R. L., and P. Robitschek. 1974. Efficiency of resin-wood particle bonding. Forest Prod. J. 24(7):22-25.nCoil, G. K., and J. B. Kasper. 1984. A liquid blending system developed by Mainland Manufacturing. In Proc. Washington State University Particleboard Symposium, Pullman, WA. 18:383-389.nCoil, M. Production Manager. Coil Manufacturing Limited, 8445-129A Street, Surrey, BC Canada, V3W 1A2. 2003a. Personal Communication. Telephone conversation with the author, 24 July.nCoil, M. Production Manager. Coil Manufacturing Limited, 8445-129A Street, Surrey, BC Canada, V3W 1A2. 2003b. Personal Communication. Telephone conversation with the author, 25 September.nCramond, P., and R. W. Knudson. 1984. Two approaches to blender design at CAE Machinery. In Proc. Washington State University Particleboard Symposium, Pullman, WA. 18:391-398.nDavis, E. W. 1919. Fine crushing in ball mills. Trans. Amer. Inst. Mining Metall. Eng. 61:250-296.nKamke, F. A., E. Kultikova, and C. A. Lenth. 1996a. OSB properties as affected by resin distribution. Pages 147-154 in Proc. Fourth International Panel and Engineered-Wood Technology Conference and Exposition.nKamke, F. A., C. A. Lenth, and H. G. Saunders. 1996b. Measurement of resin and wax distribution on wood flakes. Forest Prod. J. 46(6):63-68.nLehmann, W. F. 1965. Improved particleboard through better resin efficiency. Forest Prod. J. 15(4):155-161.nLin, F. S. 1984. The globe blending system. In Proc. Washington State University Particleboard Symposium, Pullman, WA. 18:357-370.nSaunders, H. G., and F. A. Kamke. 1996. Quantifying emulsified wax distribution on wood flakes. Forest Prod. J. 46(3):56-62.n

Downloads

Published

2007-06-05

Issue

Section

Research Contributions