34 



LOGGING 



screen plate are carried by the draft against the fine netting {E) . 



In firing up, the natural draft through (A) around (B) and under 

 (E) is unobstructed by netting. 

 This has two advantages: (i) the 

 possibility of clogging is eliminated ; 

 (2) there is an easy, free draft when 

 starting the lire. This stack acts 

 as a centrifugal separator which 

 prevents the emission of the larger 

 and more dangerous sparks and 

 only allows the escape of small, 

 light sparks which are dead by the 

 time they leave the stack. 



There are numerous other spark 

 arresters but those described are 

 Fig. 6.-TheRadley-Hunter ^he more common ones in use 

 Spark Arrester. among lumbermen. 



FUEL OIL 



Sparks from locomotives have proved such a menace to forest 

 property that in some states trunk line railroads which pass 

 through forest regions are compelled to use fuel oil during the 

 danger season because the many devices used to prevent the 

 emission of live sparks from coal-burning and wood-burning 

 engines have not proved entirely satisfactory. Fuel oil is not 

 extensively used by loggers either for locomotives or for logging 

 engines. For a short period after the discovery of the Texas oil 

 fields many loggers in the cypress region of Louisiana fitted their 

 logging engines with oil burners because fuel could be purchased 

 cheap enough to reduce the expense of operation. A marked 

 increase in the cost of fuel oil has led many to return to the use 

 of coal or wood. Many loggers in the Inland Empire and the 

 Pacific Northwest now use fuel oil successfully in locomotives, 

 but so far no method for burning fuel oil in vertical boilers has 

 been de\^sed that is satisfactory for all conditions. 



