Narration : 7. Bunsen Burner
- In order to understand the structure of the Bunsen burner, let’s put together an unassembled one.
- The Bunsen burner is made up of air regulator, gas regulator, and base.
- In the base, there is a hole with a pin in the centre for the gas to pass.
- The hole at the upper end of the gas-regulator is closed with the pin in the base when you tighten the gas-regulator screw. The flow of the gas is adjusted by screwing/unscrewing the gas-regulator.
- The hole at the lower end of the barrel is closed with the upper face of the gas-regulator when the air-regulator screw is tightened. The flow of the air is adjusted by screwing/unscrewing the air-regulator.
- First, check if the air- and gas-regulators are closed. Then, open the main gas cock.
- Bring the flame of a lighter close to the mouth of the burner and loosen the gas-regulator without touching the air regulator.
- You should get a yellow flame of gas.
- Loosen the air-regulator only. The flame color should change from yellow to dark blue.
- By using the air- and gas-regulators, adjust the height of the inner flame to approximately a half of that of the outer flame. This ratio indicates the best combustion.
- Insufficient air supply causes a yellow flame of incomplete combustion. The experimental apparatus gets covered with soot if it is heated with a yellow flame. In extreme cases, carbon monoxide poisoning might occur.
- To extinguish the burner, tighten the air-regulator screw first and then the gas-regulator screw. Finally, close the main gas cock.