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Introduction of Bunsen Burner

A Bunsen burner named after Robert Bunsen, the German chemist who introduced it in 1855 (from a design by Peter Desdega, who likely modified an earlier design by Michael Faraday), the Bunsen burner was the forerunner of the gas-stove burner and the gas furnace. It is a common piece of laboratory equipment that produces a single open gas flame, which is used for heating, sterilization, and combustion.

Parts of Bunsen burner

• Base Gas inlet: The gas inlet is a tubular projection below the air hole where the gas enters the Bunsen burner and mixes with the oxygen.
• Needle valve for gas flow adjustment
• Rotary barrel for air adjustment: The barrel is the main upright part of the Bunsen burner and the part where the flames come out. Never touch the barrel as it can get very hot while in use and can stay hot long after it has stopped being used.
• Airhole: The air hole is a coverable opening above the gas inlet of the barrel that allows air to enter the Bunsen burner, where it mixes with the gas.
  The air hole can be partially or completely covered by turning the collar.
• Collar: The collar is an adjustable metal tube that for covering or exposing the air hole. This controls how much oxygen can enter the Bunsen burner, and therefore how much oxygen can mix with the gas.
  The more oxygen that is allowed to enter the Bunsen burner, the hotter the flame will be. Always light the Bunsen burner with the air holes completely covered by the collar.
• Gas regulator: It helps to regulate follow of gas.
• Rubber tubing: It is a short section of tubing attached to the gas inlet that connects the Bunsen burner to the gas tap on your lab bench.
• Base: The base of the Bunsen burner is a flat disc that provides the support for it to stand up. It is also the safest part of the Bunsen burner to touch if you need to move or carry it, as it is designed not to get hot.

Procedure for Lighting a Bunsen Burner

1. Put on your safety goggles and lab apron. If you have long hair, make sure it is tied back.
2. Connect the rubber tubing to a gas tap.
3. Place a heat mat under the Bunsen burner if the surface area is not heat resistant.
4. Turn the collar so that the air hole is covered.
5. Light a match and hold it about 3 cm above the top of the barrel.
   Turn the gas tap to the ‘on’ position.
6. Once it is lit, extinguish the match.
7. Leave its flame in ‘safety mode’ until you need to heat something.

Temperature of Bunsen Burner

The amazing fact about the Bunsen burner is that the hottest part of the Bunsen flame which is heated just above the tip of the primary flame reaches about  1500 °C or 2700 °F. Having this type of high temperature and requiring less space, it is also called a micro incineration plant that is why also included in sterilization as a physical method.

Good and bad flame Recognition of Bunsen Burner

1. Good flame: Only blue in color
2. Bad flame:Blue with other colors

Uses of Bunsen Burner

1. Sterilization of Inoculating loop
2. Sterilization of stabbing straight wire
3. Sterilization of Forceps touched parts with specimens
4. A heating substance with help of a tripod stands using a safety flame.

Safety Rules for  Using a Bunsen Burner

As you know, the temperature of this burner is very high i.e.   1500 °C or 2700 °F, and therefore we have to follow safety rules to save from the occurrence of any incidents.

1. Always wear safety goggles and a lab apron when using this burner.
   If you have long hair, always tie it back.
2. Always light it with the air hole covered by the collar.
3. Always light a match or lighter and hold it above the Bunsen burner barrel before turning on the gas tap.
4. Never turn on a gas tap without a Bunsen attached and a match lit above the barrel.
5. Extinguish the match immediately after lighting it.
6. Always leave it on the yellow safety flame when you are not heating anything.
7. Always leave it on the blue heating flame when you are heating something.
8. Never put your hand in a flame.
9. Always extinguish a Bunsen flame by turning off the gas tap.
10. Never attempt to blow out a Bunsen flame.
11. If the flame accidentally goes out, turn the gas tap off immediately.
12. If there is a fire, immediately turn off the gas tap.

Key Notes on Bunsen Burner

1. It is one of the most requirements of a microbiology laboratory.
2. Using a Bunsen Burner
   Airhole fully open
   Type of flame: Roaring
   Purpose: To heat things fast
   Airhole half open
   Type of flame: Blue
   Purpose: To heat things slowly
   Airhole closed
   Type of flame: Safety flame
   Purpose: When we are not using the Bunsen but want to keep it on.
3. The mixture of air and gas (optimally about 1 part gas to 3 parts air)  forces by gas pressure to the top of the tube, where it ignites with a match.
4. A major purpose of the open flame in the aseptic technique is to create a cone of hot air above and around the laboratory bench to reduce the viability of organisms on suspended dust particles and thus creates a sterile zone for working.
5. The ability of its flame to heat things very quickly also makes it an ideal choice for sterilizing inoculating loops, warming glass bottlenecks, or igniting alcohol on culture spreaders, and so on.
6. Bunsen burner flames depend on airflow in the throat holes (on the burner side, note the needle valve for gas flow).

Further Readings

1. https://www.britannica.com/science/Bunsen-burner
2. https://www.sciencedirect.com/topics/engineering/bunsen-burner
3. https://www.goodscience.com.au/year-7-science/the-bunsen
4. https://en.wikipedia.org/wiki/Bunsen_burner