Bunsen burner


🏾 Contenu :



🏾 Introduction

A Bunsen burner is a type of gas burner that produces a safe, smokeless, hot, non-luminous flame that can be used for various scientific experiments.

The flame is created by the gas and oxygen being mixed in a controlled environment, which allows precise regulation of the size and heat of the burner.

The Bunsen burner consists of a flat base with a vertically extending straight tube, called a barrel or chimney. Natural gas (mainly methane) or a liquefied petroleum gas such as propane or butane is supplied at the bottom of the chimney, it is connected to a gas valve using a rubber tube.

The burner is named after Robert Bunsen, a German scientist who designed it in 1857 with his laboratory assistant, Peter Desaga.

  Bunsen burner

Bunsen burner

The basic function of a Bunsen burner in the laboratory is heating, sterilization and combustion.



🏾 Bunsen burner parts

Base : It is a wide and heavy part of variable shape which provides support for the Bunsen burner. It is connected to a side tube called the gas tube.

barrel or chimney : It is a metal tube about 5 inches long that rests on the base of the burner. It has two diametrically opposed holes near the bottom end which form the air vent. The barrel can be screwed to the base. The gas from the nozzle mixes with the air from the vent and burns at its upper end

Air holes : Air holes allow air to enter the burner to make a mixture of air and gas or other liquid fuel with air.

The air regulator (Collar ) : IIt is a short metallic cylindrical sleeve with two holes diametrically opposed to each other. Present around the ventilation holes, the main function of the collar is to control the amount of air entering the barrel.

Bunsen burner parts

Bunsen burner parts

🏾 Principle of Bunsen burner

Bunsen burners are normally fitted with a barbed fitting at the base of the chimney to allow a rubber tube to feed gas from a gas nozzle on the laboratory bench.

The Bunsen burner principle relies on its ability to mix gas (or other fuel) with oxygen before the mixture is ignited (creating a premix of air and gas before combustion). This is done by using an inlet valve at the bottom of the burner column which sucks in air by the Venturi effect, while the gas passes through a nozzle whose diameter is specific to the nature of the gas used. The mixture is then ignited at the top of the column.

The adjustable valve (collar) at the bottom dictates the amount of oxygen that enters the mix. With a closed valve, very little oxygen enters and a smoky yellow "low temperature" flame is produced. With the valve fully open, a hot, nearly colorless, roaring flame results.

🏾 Bunsen Burner Fuel Sources

There are two main fuel sources for a Bunsen burner : natural gas (mostly methane) and liquefied petroleum gas (propane, butane, or a mixture of the two). Be sure to select the correct burner for the fuel source you will be using: it is dangerous to use a burner for one type of fuel with the other fuel.

🏾 Types of Bunsen Burners

◉ There are several types of Bunsen burners to choose from depending on your gas source and experimental conditions :

  • The Tirrill burner is a subtype of the Bunsen burner that features a wing nut at the bottom of the tube to regulate the gas supply. Minor gas adjustments can be made by turning this valve.
  • The Meker burner is a subtype of the Bunsen burner that is designed to produce an extremely hot and stable flame. The chimney is flared and the division of its flame by a grid at the top of the chimney gives a much shorter, more powerful flame (+ 1180°C) and quieter but with a higher gas consumption.



🏾 What are the types of flame on a Bunsen burner?

◉ Safety Flame : This flame is yellow, easy to see in a well-lit room, and helps others remember that your Bunsen burner is on. Reaches temperatures of approximately 300 degrees, not used to heat materials for experiment.
Explanation : When the vent of a Bunsen burner is closed , the air needed for the combustion reaction comes only from the area near the top of the burner, incomplete combustion, resulting in a bright yellow flame resembling a candle.

◉ Medium blue flame : This particular flame on a burner can reach 500 degrees. Can be difficult to see in a bright room and is created when the air gap is partially open.

◉ Roaring blue flame : (It's the only flame that makes noise) This is the hottest flame, it can reach temperatures of 1400 degrees, with the hottest part of the flame just at the tip of the white cone in the middle of the blue flame.
Explanation : Increasing airflow to the burner produces more complete combustion and a hotter flame. The gas-air mixture is then ignited above the barrel. The result is a noisy, bluish-colored three-cone flame. This blue flame provides the highest possible burner temperature.

Types of flames Bunsen burner

Types of flames


References:

  1. Chemistry Lab Manual - Bunsen Burner
  2. Flinn scientific - Bunsen Burner Basics
  3. Biologie sans frontière - bec Bunsen
  4. William B. Jensen - Ask the Historian : The Origin of the Bunsen Burner
  5. ExamplesPedia - Bunsen burner Parts and Their Functions
  6. Lisa Nichols - Becs Bunsen
  7. Matt Bertrand - Understanding Products: Bunsen Burner
  8. Erin R. Sanders - Aseptic Laboratory Techniques: Volume Transfers with Serological Pipettes and Micropipettors
  9. Edulab - the Bunsen Burner – What is it and how to use it safely