DUST KXPLOSrOXS IN" GRAIX SEPARATORS. 



NATURE OF EXPLOSIONS. 



Tho nature of the explosions and fires in 117 cases can Ijc sum- 

 marized as follows: 



Fires. 



Without explosions 



jSature not dotormined- 



21 

 1 



22 



Explosions. 



Sudden puff 68 



Very violent 8 



Small puff 10 



Slij^ht explosion 2 



Mil filed and quick 5 



I'laine followed by explosion 1 



Ix'tonation report 1 



95 



This table indicates that at least 95 of the occurrences, or 81 per 

 cent, were dust explosions. In the remaining cases where there was 

 suflicient flame to damage the machine the fire was not accompaniwi 

 by as loud reports ms in the other instances. The ignition was not 

 so rapid and the rate of burning accordingly slower. 



POINT OF ORIGIN OF EXPLOSIONS. 



Special efforts were made by the investigators to locate the point 

 of origin of the explcjsions and fires. 'J'lie results in 108 cases can ha 

 summarized as follows: 



Back of cylinder or near 



point 



Entire machine 



B(;hind l<nives 



r.lower 



(Jenter of machine 



Front of madiine 



this 



82 

 9 



Grain pan 1 



Straw stacli 1 



liack of machine 1 



Engine 1 



108 



At least 82 of these occurrences, or 70 per cent, originated back of 

 the cylinder or very near this point, indicating that the source of 

 ignition in a large majority of ca,ses was near this part of the 

 s<i para tor. 



LOCAL OPINION AS TO CAUSES. 



Dijring the preliminary field investigations an effort was made to 

 interview the thresher agents of the various companies in the vicinity 

 of Spokane and other interested parties with a view to obtaining 

 information pertaining to the local opinion regarding causes of pre- 

 vious explosions and fires. Prior to 1914 occasional occurrences of 

 this nature had taken place throughout the Pacific Northwest, but 

 until 1914 general interest was not awakened. During that year, 

 owing to the frequency of the explosions and fires, local interest was 

 gr<!atly increased. 



