GAS AS A FUEL 



159 



Types of the Bunsen Burner used on Gas Stoves. There are two 

 types of burners in general use on gas stoves. One is used for 

 boiling and frying, and is so arranged as to produce a number of 

 flames in a ring or star. The other type of burner is used for baking 

 or broiling, and is so arranged as to have a number of 

 little flames in a row. 



Adjustment of Gas Burner. The flame of a gas 

 range should be so adjusted that the cross-sectional area 

 of the outer cone is less than the cross-sectional area of 

 the inner cone. The mixing disc near the stopcock 

 should be so adjusted as to admit air enough to pro- 

 duce a blue inner cone. If too little air is allowed 

 to enter, a yellow tip will appear on the cone; if too 

 much, the burner will " flash back " or " burn back," 

 and burn near the spud, or the inner cone will take 

 on a greenish hue. This means that combustion is 

 not complete. Acetylene, carbon monoxide (a very 

 dangerous gas) and other poisonous gases will be 

 given off, since the gas is only partly burned. The 

 gas must be shut off and relighted, or the air mixer 

 closed slightly, and then readjusted after the flame 

 is lighted. The " flash back" is really an explosive 

 action which carries the flame into the mixing tube 

 and sets up combustion at the gas orifice. 



Gas stove burners should be so adjusted that the 

 blue-green central part of the flame is about half the 

 height of the whole flame. If the flame is very long, 

 and is bright yellow in part, too little air is being 

 admitted; if short, and inclined to make a slight 

 roaring noise, there is too much air. In the latter 

 case the flame is liable to " strike back." In all gas burners the 

 various openings should be kept clean. 



Explosions are often caused while lighting the burners in a gas 

 oven because large quantities of air mix with the gas which has 

 entered the oven. The oven door should always be left open 

 while the burners are being lighted. 



The distance from the bottom of a dish on a gas stove to the 



FIG. 131. 

 Why are 

 there holes 

 in the disc? 

 How could 

 this burner 

 be ad justed 

 to get a 

 blue flame? 



