DEVELOPMENTS IN OIIv BURNING. 



249 



tested out experimentally and what is more to the point, nobody is doing it, 

 not even the users of the Koerting apparatus itself . The dangerous expedient, 

 therefore, of heating oil above its flash-point at atmospheric pressure is not 

 found necessary. 



EFFECT OP HEATING OIIv ON VISCOSITY. 



The real value of heating the oil is rather a mechanical one — namely, to 

 reduce the viscosity of the liquid so that it can be forced through the small 

 passages of the burner and given a rapid whirling effect, sufficient in the 

 more limpid condition of the oil to reduce it to a fine spray through the action 

 of centrifugal force when liberated from the tip. 



Viscosity fcy En^icr Viccosijneter . 



Fig. 2. — Temperaturb- Viscosity Chart. 



50 



eo 



It will be found from a study of fuel oils that, while the viscosity is 

 tremendously affected by changes in temperature at the lower ranges, very 

 little difference in viscosity results with heating or cooling as the temperatures 

 approach the flash-point. A number of viscosity tests at various tempera- 

 tures on a variety of oils were made for the writer by Mr. E. G. Bashore, 

 chemist for The Babcock & Wilcox Company, the results of which are shown 

 graphically in Fig. 2 and serve to illustrate this condition. 



