PROTECTION OF FOREST PROPERTY 



33 



ing spring. Engineers who have used them state that they do 

 not interfere with the draft. The cost of manufacture in a rail- 

 road shop is about $3 each. 



Boomerang Spark Arrester} — This is used by many loggers on 

 the Pacific Coast for coal-burning and wood-burning stationary 

 engines. The essential parts of the ar- 

 rester, Fig. 5, are a heavy j-inch mesh 

 round screen {A), shghtly flaring toward 

 the top, on which is mounted a heavy 

 sheet iron cone {B). The latter ends 

 in a boomerang (C) to the open end of 

 which a screen conveyor tube {D) is at- 

 tached. The smoke passes out through 

 the screen while the sparks travel 

 straight up through the steel cone 

 where they are diverted into the boom- 

 erang and led into a receptacle by the 

 side of the engine. As the sparks do 

 not come in contact with the screen it 

 does not become clogged. The prices 

 vary from $20 to $38 each according 

 to the size. 



Radley-Hunter Spark Arrester? — This is an effective loco- 

 motive spark arrester which is used by many lumber companies, 

 especially in the West. 



The smoke and exhaust pass up through the main smoke 

 chamber {A), Fig. 6, striking against a spiral cone {B) which gives 

 it a whirHng motion, and the large cinders are thrown outward by 

 centrifugal force against the perforated screen plate (C). This 

 plate has openings in it large enough to permit the passage of 

 sparks into the spark chamber {D). Once through this per- 

 forated screen plate they are beyond the Hne of active draft, 

 and by their weight fall into the cinder receptacle (G) from which 

 they are removed through the cleaning out holes {F). The 

 lighter sparks which are not thrown through the perforated 



' Manufactured by the Washington Iron Works, Seattle, Washington. 

 2 Manufactured by the Lima Locomotive and Machine Co., Lima, Ohio. 



5. — The Boomerang 

 Spark Arrester. 



