Modern Bunsen Burner

Flame sterilization is a routine task carried out in many microbiological, clinical and life science laboratories. Bunsen burners provide a flame with temperatures up to 1’200°C. Natural gas (primarily methane), liquefied petroleum gas such as propane, butane or a mixture of both are used as fuels. The gas flows through a small opening at the base of the barrel and is directed upwards. Air vents at the tube bottom permit air to enter the gas stream by the Venturi effect. The amount of oxygen (air) mixed with the gas stream defines the completeness of the combustion reaction. Thus, a gas stream well mixed with oxygen results in a complete and hotter reaction than with less oxygen. The air rich flame appears blue and creates a roaring noise whereas an incomplete combustion results in a noiseless and yellow flame. The highest temperature within the blue flame is obtained at the tip of the inner cone. Thus, for efficient annealing, the object has to be inserted at this position.