﻿KILN DRYING HANDBOOK. 



be secured with reasonable accuracy from the distribution section 

 alone by assuming the original weights of all the pieces to be the 

 original weight of the section, and similarly with the dry weight. 

 The entire calculation will be as follows : 



Shell. 

 Original weight =60 

 Oven-dry weight=50 

 ,, . 10X100 



Moisture= — ^q — 



==20 per cent 



Core. 

 Original weight =100 

 Oven-dry weight= 80 



20X100 

 Moisture = — ht; — 



=25 per cent 



Section. 



Original weight =160 

 Oven-dry weight=130 

 „ . 30X100 



Moisture= — ToK — 



=23.1 per cent 



GENERAL PRINCIPLES OF DRYING WOOD. 



The drying of wood is a very complex process, concerning many 

 phases of which we are still uninformed. However, it is not essential 

 that the operator understand all of the details of the movement of 



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Fig. 1. 



-Method of cutting sections from board or plank for making moisture distribution 

 determinations. 



the moisture through the wood, and all of the attendant phenomena. 

 Let him take it for granted, for the time being, that the moisture 

 tends to distribute itself evenly through the wood, moving from the 

 more moist regions to the drier ones. 



This movement of moisture within the wood is affected by three 

 controllable external factors — heat, humidity, and circulation. A 

 constant application of these factors in proper proportion is essen- 

 tial to the successful drying of lumber to the moisture content re- 

 quired for a sj)ecific use. The regulation of the heat, humidity, and 

 circulation is, in fact, the main problem in the successful operation 

 of kilns. 



