A NATIONAL PLAN FOE AMERICAN FORESTRY 1385 



tion could be performed in the same way on any given pulp. Methods 

 of really measuring the effects of beating are lacking and must be 

 developed. It is not even known with certainty whether " hydration " 

 as known to the paper maker is a chemical or a mechanical effect. 



PAPER MACHINE OPERATING FACTORS 



The best-directed efforts to produce a pulp that will make paper 

 of excellent quality can be defeated by faulty machine operation. 

 Tests indicate, for instance, that the strength of sheets can be lowered 

 33 percent and porosity increased 100 percent by draw manipulation 

 alone. In order to put the papermaking procedure on an engineering 

 basis as free as possible from purely empirical practice, research 

 looking to the isolation, measurement, and control of the machine 

 operating factors is essential. 



This is no simple task. At least 75 independent or dependent 

 variables have been identified on the paper machine, a few of the 

 more important being consistence of stock passing to the wire, 

 relative speed of stock and wire, effect of stock temperature, hydro- 

 gen-ion concentration of the stock, rate of drainage to effect formation, 

 couching pressure, rate of moisture removal in presses, drying rate, 

 amount of draw, and calender pressure. 



MILL WASTE UTILIZATION AND WASTE PREVENTION 



Large opportunities for operating economies and increased returns 

 await the work of practical research in the utilization of wood-room 

 wastes and mill effluents. Bark has ordinarily been a total waste in 

 pulp manufacture. A small amount of investigative work has been 

 done to develop methods of using bark for fuel or for special products. 

 There is need for much more. It is estimated that wood fiber to a 

 value of $10,000,000 goes down mill sewers annually, suspended in 

 the " white water" discharge. This waste would not occur in the 

 line of ordinary business if the over-all economy of saying it could be 

 demonstrated in general practice. A third obvious line of economy 

 in production is the utilization of spent liquors. The sayings possible 

 in the reuse of waste sulphite liquors in a second pulping treatment 

 have been partly demonstrated, and still greater gains lie in the 

 possible utilization or recovery of sulphite liquors now discharged, 

 containing as they do all the chemicals of the pulping reaction and a 

 full half of the raw material. 



Determined efforts should continue toward the elimination of 

 fiber losses due to the decay of pulp and pulp wood. The latter is 

 subject to deterioration from the time of cutting until it is delivered 

 to the grinder or chipper for conversion into pulp. Under com- 

 mercial conditions of handling, deterioration of wood is particularly 

 rapid in the second and third years of storage. A further source of 

 loss is the reduction in quality due to the deterioration of the pulp 

 into which the wood is converted. While the development of anti- 

 septic chemical treatments and of improved methods of handling 

 pulp and pulpwood have aided considerably in reducing losses, work 

 is still needed to insure commercial applicability of research findings. 

 In addition, the use of new woods and the changing conditions and 

 methods of handling continue to introduce new problems of deteri- 

 oration that demand study. 



