TECHNICAL LIBRARY

 

Wood Flour Quality Improved by Installing Centrifugal Sifters

Bemis Manufacturing Company's Contract Wood Division, Sheboygan Falls, WI, manufactures molded products made of resin and wood flour. The boards and shapes are used for cabinet components, table tops, laminates, toilet seats and miscellaneous products. In an effort to allow their mills to run at full capacity, cut the number of rejects and reduce costs associated with machining rough surfaces caused by oversized particles of wood flour, a scalping system was installed to ensure that only wood flour particles smaller than .015 in. are mixed with binder and compressed into the desired shape.

Because of their ability to quickly ship six reliable CENTRI-SIFTER Centrifugal Sifters, Kason Corp, was selected to provide the heart of the scalping system, One experimental MO unit was shipped three days after the order was placed, two stainless steel loaner units were shipped three weeks after the order was placed, two YO models were shipped seven weeks after the order was placed, two YO units were shipped 9 one-half weeks after the July 24th order, and one YO was shipped 10 weeks after the order. These units have enabled us to get started when we wanted to and have worked well, according to Jeff Trowbridge, director of plant engineering.

Operating at about 1100 lbs/h for periods up to 24 hours per day, five of the units scalp the warm flour from the mills. Overs are recycled back into the mills. Both hardwoods (except oak due to high tanic acid levels) and softwoods are used. By using wood flour for its products, Bemis ensures that more of every tree cut can be put to good use. Also, the use of wood flour eliminates any weak spouts due to knots, checking, or other natural imperfections that solid wood exhibits. The strength of the material made of wood flour is equal or greater than that of naturally grown solid wood, and the reconstructed wood is equally strong in all directions.

How It Works

Wood flour is uniformly fed into the cylindrical sifting chamber by means of a feed screw which discharges into a rotating helical paddle. Centrifugal force accelerates the flour against the nylon screen. The rotating paddles, which do not contact the screen, propel individual particles through the screen. Oversized particles and trash are ejected and pass directly to the discharge spout. From there, the oversize flour particles are returned to the mill as mentioned.

When worn beyond further use, a screen can be replaced with ease in less than two minutes, and a CENTRI-SIFTER unit is easy to clean. Double seal outboard bearings in the motor help enable this design to provide hours of quiet vibration-free operation. The motors are sized carefully to operate effectively and efficiently.

In addition to compressing wood flour into boards and shapes, Bemis Manufacturing Company Contract Wood Division is equipped for routing, drilling, tenoning, machining, sanding, woodburning, silk-screening, custom finishing, assembly, custom packaging and providing engineering assistance.

The addition of these CENTRI-SIFTER units has enabled Bemis Manufacturing Company's Contract Wood Division to significantly increase production by running mills at their full capacity without being concerned about problems associated with oversize particles. Also, quality has been improved by reducing the number of blemishes appearing on surfaces and the number of pieces that previously would have been rejected.

Screen Tips - Volume 6, Number 3 Fall 1991

Wood Flour Quality Improved by Installing Centrifugal Sifters

Kason CENTRI-SIFTER™ Centrifugal Sifter scalps wood flour at Bemis Manufacturing Company's Contract Wood Division, Sheboygan Falls, WI. The CENTRI-SIFTER unit ensure that only wood flour particles smaller than 0.015 in. are mixed with binder and compressed into the desired shapes.