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Chapter 23 



WATER SPRAYS 



INLET 



WICKETS 



1 ^-^-Hi ^ 



PERFORATED STEAM PIPE 

 HEATING COIL 



D-| WET AND DRY BULB THERMOMETERS 



OUTLET 



Figure 23-92. — Wicket-type continuous humidifier. (Drawing after Wehrle 1957.) 



Other methods of humidification include the spraying of water on the back 

 side of the board, followed by stacking (back to back), the application of vacuum 

 to force moist air through the board, and the application of liquid water by roll 

 coater followed by surface heating through contact rolls which causes dispersion 

 of the water throughout the board. 



23-11 FABRICATING AND FINISHING 



Cutting fiberboards from the dimensions at which they are pressed to product 

 dimensions, and laminating, scoring, and punching them is called fabricating. 

 Fabrication of medium-density fiberboard is generally limited to cutting to size. 



Very little hardboard and insulation-board, however, is sold as "brown board" 

 in standard-size sheets. Most boards are extensively fabricated and finished to 

 make products ready for installation. Many manufacturing lines produce exclu- 

 sively interior paneling, or tileboard, or siding. This specialization influences 

 raw material selection and pulping procedure. 



INSULATION BOARD FABRICATING AND FINISHING 



Figure 23-94 schematically represents the fabricating and finishing depart- 

 ment of an insulation board plant producing single-thickness or laminated prod- 

 ucts, painted or asphalt coated. Such production lines are designed for great 

 flexibility, permitting inclusion or omission of laminating, edge and surface 

 machining, and finishing. As the first- and second-pass trim saws are coupled 

 direcdy to the dryer, emergency storage is provided after these saws adequate for 

 about one hour's production. For a description of the trim saws see paragraph 

 Two-pass tenoners in sect. 18-20, fig. 18-224, and related discussion. 



Dyer's (1960) description of the rest of the operation diagrammed in figure 

 23-94 is summarized as follows. To laminate boards following trimming, they 



