14 BULLETIN 379^ U. S. DEPARTMENT OF AGRICULTURE. 



CHEMICAL FIRE EXTINGUISHERS. 



The chemical extinguishers in use were arranged to be tripped by 

 hand. They consisted of a tank containing water charged with 

 bicarbonate of soda and a bottle containing sulphuric acid. The 

 tripping device either upset the bottle or liberated a hammer that 

 broke it. The extinguishers in use in the field worked with varying 

 degrees of success. 



WATER UNDER PRESSURE. 



A number of separators were equipped with w:ater tanks that could 

 be pumped to 100 pounds pressure by a special air pump and were 

 provided with a system of piping from the tank to the separator 

 much the same as was the chemical extinguisher. The results ob- 

 tained did not appear to be satisfactory, possibly due to the fact 

 that as soon as some of the water had sprayed out the pressure 

 dropped so rapidly that there was not sufficient pressure remaining 

 to be effective. However, a number of machines were saved from 

 total destruction by using this type of extinguisher. 



One machine was equipped with a 40-gallon water tank on top of 

 the separator connected to the engine pump w^hich maintained a 

 pressure of TO pounds. In case of fire, hy the pulling of a wire, the 

 pipes from the tank were opened and the water carried to per- 

 forated pipes in the separator. As no fires occurred in this machine 

 the tank did not receive a thorough trial. 



STEAM LINE FROM BOILER TO SEPARATOR. 



Steam or water hose from the engine boiler to the separator was 

 used in many cases with satisfactory results. Its popularity was due 

 to the comparative cheapness of the system (about $50 to $75) and 

 also to the success attributed to it by the men who had used it. Best 

 results were obtained when regular steam hose was connected to a 

 point on the boiler below the water line. When a valve was opened 

 at the boiler a pressure of steam and water was obtained which 

 usually was successful in extinguishing the fire. 



Where it was difficult to secure steam hose and it was not consid- 

 ered safe to use ordinary rubber hose the line was composed of 

 steam pipe. This made a much more clumsy installation, but it 

 worked successfully when necessary swinging joints were properly 

 installed. 



FURTHER EXPERIMENTAL WORK. 



In addition to the investigations made in the field based on actual 

 explosions and fires an attempt was made to study in the field or in 

 the laboratory the following: 



