With a Dry Kiln in the Northwest 119 



of all lumber put through the drying process is of that material. 

 The company also owns a shingle mill in close proximity, but as 

 it has its own steam and dry kiln it is not connected in any way 

 with the main plant. 



The kiln at the mill has five chambers and is constructed, 

 with the exception of the roof, which is of wood with a tar 

 paper covering and a plaster ceiling, entirely of reenforced con- 

 crete. The walls are approximately 20 inches thick at the bottom 

 and gradually taper to about 10 inches at the top. At different 

 points they are made extra thick for strength. Each chamber is 

 connected to the next with vents for freer circulation of air. In 

 length each one is 112 feet, in width 25 feet, and in height 11 

 feet, with a space of from 3^ to 4y 2 feet below the rails. At 

 each end is a light asbestos door opened and shut on rolling 

 hangers. The whole kiln is built on piles from 5 to 6 feet above 

 the ground, because of the absence of otherwise solid footing. 



Non-draught with steam radiator pipes below is the method 

 of drying. This is in contrast to the natural draught and the 

 blower methods of many of the kilns in other mills. The former 

 like the non-draught is heated with steam pipes below but has 

 a circulation of air commencing from the bottom of the "dis- 

 charge" end and exhausting through ventilators near the ceiling 

 at the "charge" end. In the latter method, by means of a power- 

 ful centrifugal fan a circulation is maintained in which the air 

 passes through a furnace-like heater, circulates through the kiln 

 and returns again to the fan. 



For furnishing heat, series of one inch pipes are laid between 

 the three rails over which the lumber is placed. These pipes are 

 on a slight decline for drainage. There are three series of 64 

 pipes each and two of 12, giving a total of 216 pipes, each of 

 which is 98 feet long. This gives a total of 21,168 feet of 

 radiating pipe for each chamber, or 105,840 feet for the entire 

 kiln, beside the two inch connecting pipes. 



Approximately one-third of the output of the mill was kiln- 

 dried. In 1913, 574 cars or 2,755,200 feet B. M. were run through 

 in March ; 647 cars or 3,105,600 feet in April ; and 596 cars or 2 - 

 940,800 feet in May. This gives a daily average of nearly 100,000 

 feet B. M. From all observations a greater percentage of material 

 was kiln-dried at this mill than at the average mill of this entire 

 region. But it is perhaps safe to assume that one- fourth of the 

 entire output reaches the kilns; and if such is the case, then the 

 yearly kiln-dried lumber amounts to approximately one billion 

 feet B.M. for Washington and half that amount for Oregon, 



