Bunsen burner is a type of gas burner discovered by Robert Bunsen in 1857, who is a German scientist. To initiate various chemical reactions like combustion, it produces a smokeless and non-luminous flame due to the presence of air that enters the chamber. Thus, the source of gas in the burner could be methane, ethane, propane, etc. These all are natural gases and can be controlled by the burner.
Principle of Bunsen Burner
Bunsen burner uses the gas flows from the source through the gas nozzle, which goes in the upper direction from the bottom of the burner. It occurs due to the presence of a small hole that is present in between the chimney and the bottom part of the burner.
Using the venturi effect, when the fluid flows through the constricted pipe or a hole, then its pressure decreases due to an increase in velocity of the liquid, so the Bunsen burner, while making use of the venturi effect, allows the air to enter the barrel through the air holes and the same gas exits the barrel with high speed and resulting in burning of flame.
Thus, the amount of air supplied is directly proportional to the strength of the flame, which also affects the color of the flame.
Due to this, the color of flame varies and can be identified using its strength of it. Thus, the color of the flame can be changed or influenced by adjusting the holes of the burner.
For instance, if an air hole is,
- Closed completely, then it shows yellow color, which is the safety fire.
- Minutely opened produces a flame of red color which has slight combustion power to it.
- Half opened hole gives the purple flame, which has half the combustion capacity.
- A fully opened flame produces blue color, which is very dangerous as it has full combustion power.
Procedure of Operating Bunsen Burner
- Turn on the main gas source. If the source is directly from the gas cylinder, then plug in the regulator of the cylinder and turn down the knob of it to open.
- Check for any leakage of gas and then proceed further.
- Keep the air vent in half to avoid the supply of gas too much or too little, which will create problems in lighting the burner.
- Flame the burner using the lighter. One can hear the hissing sound because of the sudden lighting of gas, and to avoid the gas from flaming too much, then lighten from the sides of the burner.
- Now, adjust the air hole to keep the color of the flame at bluish color, and the flame should not flicker too much and should be stable. The ideal gas flame should be 10cm high, pale blue, or slightly colorless.
- After operating, close the gas outlet to flame off the burner. And, the main source of gas should also be switched off.
Parts/components of Bunsen Burner
- Barrel/ chimney:
- Longest part
- Made up of metal
- Length: 5-6 inches.
- From the inside, it is hollow and narrow to increase the flow of mixing of gas and oxygen.
- Aka air regulator
- Location: base of the barrel
- Regulate the amount of oxygen that can enter the air valves.
- Can rotate clockwise and anticlockwise
- Clockwise rotation reduced the amount the heat, thus producing the yellow color flame with low combustion power.
- Anticlockwise rotation increases the amount of heat-producing blue flame with the highest combustion power.
- Air holes:
- Opening on burner
- Allow oxygen to enter the barrel from the collar.
- Gas valve:
- Connected internally with the gas nozzle, which is the gas receiving part.
- The supply of gas can be controlled by rotating it left or right.
- Gas nozzle:
- Allow natural gas to enter the burner
- This is done by connecting the nozzle to the gas source using a rubber or plastic pipe
- The lowest and heaviest part
- Stabilize the burner vertically.
- Disc or flat-shaped
- A disc shape is preferred due to its center of gravity.
Types of Bunsen Burner
- Meker fisher burner:
- They have a larger diameter barrel in comparison to the Bunsen burner.
- Due to its larger size, the mixing of air and gas is more.
- They are equipped with an extra grid that covers the top of the barrel and separates the flame into smaller flames.
- The supply of gas is controlled using a gas valve or needle valve which is present at the bottom of the chimney or barrel.
- Teclu burner:
- More efficient than the Bunsen burner in producing heat.
- The barrel tube is longer than other types of burners.
- Air and gas mix very well.
- The combustion power of flame is comparatively higher.
- Equipped with a screw nut to adjust the gas source present below the barrel tube.
- Tirrill burner:
- At the bottom of the barrel, they have a disc valve
- The valve controls the amount of gas and thus the combustion power of the burner.
- Temperature can rise to 1560 -1575 degrees Celsius, producing blue flames.
Uses/ Applications of Bunsen Burner
- Sterilization of inoculation loop and spreader for microbiology-related experiments.
- Sterilizing neck of beakers and flask to maintain the aseptic condition
- Provide a contamination-free environment for research laboratory purposes.
- Used for combustion
- Identification of crystallized water
- Drying of salts
- Compounds flammability
- Analysis of moisture content
- Solvents flashpoints
- Dehydration of complexes
Advantages of Bunsen Burner
- Easy operation
- It can be used wherever gas is available
- No need for electricity
- It can be used not only for heating but also for simple glass-blowing work
- Available in many different sizes and types for operators’ convenience and requirements.
- Temperature using this can reach up to 1500 celsius.
Limitations of Bunsen Burner
- Risk of fire accidents.
- Temperature control at the desired level is not possible.
- Before operating the Bunsen burner:
- Inspect all the types of equipment before operating for damage and replace or remove them if required.
- Everyone in the lab near the burner should be aware that the burner is operating.
- Combustible material like ethanol or sanitizers should be kept away from it at all times.
- Secure any loose hairs, jewelry, or clothing, especially the sleeves of the lab coat, before operating.
- Check for any gas leakage as soon as you enter the room containing the burner. If found one, then open all the windows and do not operate it for some time.
- Do not directly sanitize or sterilize your hand and start working. Instead, let it dry, or it’ll catch fire.
- While operating Bunsen burner:
- Keep the lighter or sparker ready before operating it.
- Avoid using matchsticks to light the burner.
- Make sure to close the needle valve or collar completely and check all the connections.
- Never leave it unattended.
- Keep the gas valve shut off so that the burner is still on and the flame extinguishes accidentally.
- After operating the burner:
- The gas valve should be off.
- The regulator of the gas source should be removed, or the main connection of gas in the lab should be turned off.
- Avoid touching anything until it cools down completely.