subject: Key Features of Bunsen Burners [print this page] Key Features of Bunsen Burners Key Features of Bunsen Burners
A Bunsen burner is a commonly used laboratory apparatus which produces a gas flame. It is used for heating and providing combustion during laboratory experiments.
It is commonly accepted that a blue flame provides more heat and generates less soot while burning. On the contrary, a yellow flame consumes more energy while burning but does not yield as much heat. To provide an efficient burner which focuses energy into a blue flame, the Bunsen burner was invented by Robert Bunsen in 1855.
The burner is based on the principle of moderating the supply of air along with a combustible source like gas to ensure that the desired intensity of flame is obtained. It consists of a cylindrical metal tube with a base at the bottom. There are inlets for supply of gas at the lower end of the metal tube, which may include a valve for adjusting the air and gas supply.
The combination of air and gas can be regulated to ensure higher or lesser flow of air along with the gas to produce the desired flame. The normal ratio of air and gas used in the burner is three parts of air along with one part of gas. The pressure of the gas forces the gas and air mixture to the top of the cylindrical metal tube. This is then ignited with the help of a match box or a lighter.
A Bunsen burner can generally be used to produce three different types of flames. A yellow or orange flame is normally the coolest and is also known as a safety flame. This is normally a test flame before adjusting the burner for other types of applications. It merely indicates that the burner is on. The approximate temperature of the safety flame is 300 degree centigrade.
The intermediate flame is the blue flame or the invisible flame. It is called invisible flame because it is very difficult to find out in a brightly lit room. The temperature of an intermediate flame is approximately 500 degrees centigrade. It is one of the most commonly used flames in a Bunsen burner.
The hottest flame which can be generated by a Bunsen burner is called a roaring blue flame. The temperature of this flame is 700 degrees centigrade or more. The main feature of this flame is the presence of a light blue triangle right in the middle. It is also the only flame which makes a noise while burning.
Though several other variants of burners which are used in the laboratory have been devised, the Bunsen burner remains the most popular. It has been the principle on which modern day gas stoves and burners have been designed.
