2850 Chapter 23 



H- 



+ 

 + 



+ 

 + 



+ 



Figure 23-79. — Forces on dipole in electric field. Charge shown on dipole end is net 

 result of minute charge separations occurring throughout the dipole. (Drawing from 

 Suchsland and Woodson 1985). 



F<* &^ 



Table 23-8 — Relationship between board thickness and line speed of the 

 Mende continuous board process^ 



Board thickness 

 (mm/inches) Line speed 



Meters/minute Feet/minute 



3.0/. 118 15.0 49.2 



3.2/. 126 14.0 45.9 



4.2/. 165 10.7 35.1 



4.8/. 189 9.4 30.8 



5. 6/. 220 8.0 26.2 



6. 3/. 248 7.0 22.9 



'Data from Bison Werke, Springe, Germany; promotional literature. 



For manufacture of fiberboard the process requires installation of a vacuum 

 former, replacement of the steel band by a wire screen, and addition of a band 

 prepress (fig. 23-78 bottom). Handling, drying, and blending equipment would 

 be similar to that used in other dry processes. 



BOARDS WITH ORIENTED FIBERS 



Solid wood is strong in the grain direction due to the parallel alignment of the 

 wood cells in that direction; this alignment also accounts for wood's lower 

 strength properties and greater swelling and shrinking perpendicular to the fiber 



