UNITED STATES DEPARTMENT OF AGRICULTURE 



BULLETIN No. 681 



Also Bulletin 26 of The Engineering Experiment Station, 

 The Pennsylvania State College. 



Contribution from the Bureau of Chemistry, CARL L. 

 ALSBERG, Chief, 

 And the Engineering Experiment Station, The Pennsyl- 

 vania State CoUege, R. L. SACKETT, Dean. 



jru^^>-r<^ 



iVashington, D. C. 



May 18, 1918 



GRAIN-DUST EXPLOSIONS: 



[NVESTIGATION IN THE EXPERIMENTAL ATTRITION MILL 

 AT THE PENNSYLVANIA STATE COLLEGE. ^ 



By B. W. Dedrick, Instructor in Milling Engineering, and R. B. Fehr, Assistant 

 Professor of Mechanical Engineering, The Pennsylvania State College, in collaboration 

 with David J. Price, Engineer in Charge, Grain-Dust Explosion Investigations, 

 Bureau of Chemistry, Department of Agriculture. 



CONTENTS. 



)bject and scope of the investigation 1 



i'rinciples imderl jing grain-dust explosions . . 4 



Apparatus used in investigation 6 



Materials used in investigation 10 



i^xperimental work 10 



ixperiments from April 6, 1916, to October 



3, 1917 12 



Discussion of results and conclusions 



Summary of conclusions 



Appendix : 



Recommendations for future investiga' 

 tions 



R6sum6 of some past explosions 



Bibliography 



Page. 

 39 



OBJECT AND SCOPE OF THE mVESTIGATION. 



The great loss of life and property resulting from explosions in coal 

 nines, flour and feed mills, grain elevators, thrashing separators, etc., 

 emphasizes the fact that carbonaceous dusts are very inflammable 

 md that careful laboratory and field investigations should be con- 

 lucted in order to devise means for combating this great danger. 

 Although Faraday in 1844 suggested that coal dust suspended in air 

 vould propagate an explosion, it has been recognized only within the 

 3ast 30 years that coal dust is explosive without the presence of 

 I combustible gas. And not only coal dust, but many other carbo- 

 laceous dusts are now known to be very inflammable and capable 

 )f propagathig flames. Some idea of the large amount of attention 

 :hat has been given to the explosibihty of dusts can be gained by 

 referring to the bibhography at the end of this bulletin (p. 52) and 

 bo that printed in Bureau of IMines Bulletin 20, which deals particu- 

 arly with coal-dust explosions. 



1 The erection of the mill and the conduct of the experiments were under the charge of B. W. Dedrick 



md R. B. Fehr, of the Department of Mechanical Engineering, assisted by P. X. Rice, R. E. Campbell, 



md E. F. GnandhoefEer, instructors in experimental engineering, and C. L. Charles, student assistant. 



50220° — 18— Bull. 681 1 1 



