14 



BULLETIN 322, TJ. S. DEPARTMENT OF AGRICULTURE. 



a 10-pound washing and beating engine; and a wet machine capable 

 of producing board sheets 15 by 22 inches. 



After several preliminary tests on the small machines it was found 

 that flax straw bleached with 14 per cent of lime for 15 hours at 170° 

 C. and washed and beaten in the regular manner made a board which 

 was almost invariably too hard and brittle, but if used with an equal 

 amount of bleached old mixed string and an equal amount of bleached 

 board cuttings a satisfactory board could be made. Still there was 

 usually a little too much brittleness. 



Test No. 115. — A test was then made, designated as No. 115, using 

 the large beater and wet machine. Two charges of 255 pounds each 

 were made in a rotary pulp boiler, bleaching with 14 per cent of 

 burned lime at 170° C. for 15 hours. About 275 pounds, dry weight, 



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I 11"" li* * -X. 



HhAI ^k ^^^ 55 ■*! 



Fig. 4. — Fiber-board press or calender. 



of this stock was charged into a 700-pound beater and washed and 

 beaten with a hard brush for 2^ hours, after which the roll was raised 

 and the washing continued one hour longer. The wood was reduced 

 and removed to a considerable extent, and, although the bast fiber 

 was reduced in length somewhat, there was no bast-fiber loss in the 

 wash water. At this point the workmen pronounced the stock very 

 similar in appearance and action to that from flax waste. 



The washed flax was then added to a beater containing an equal 

 weight of bleached mixed strings, which had been washed and beaten 

 for seven hours, and an equal weight of bleached board cuttings was 

 added. The furnish therefore was one-third mixed strings, one-third 

 flax straw, and one-third board cuttings. This charge was beaten 

 down, sized, and loaded by the experienced beatermen of the com- 

 pany in the equivalent of 12 hours total time. The stock was run 

 into board on a regular 44-inch wet machine and dried in the loft 



