Page 7 BUNSEN BURNER (TIRRILL TYPE) Our laboratory burner is a modification of the one designed by the German chemist Robert Bunsen. It is the source of heat for most general chemistry experiments. The Tirrill burner admits a rapidly moving stream of gas at the base of the burner which draws air into the barrel through the side air vents. This mixture of gases undergoes combustion at the top of the burner and provides a reliable and steady source of heat. Barrel Air vents Gas Inlet Needle valve (for gas control) A properly adjusted flame is capable of providing temperatures of up to about 1500C at its hottest part, which is at the top of the inner blue cone. Violet oxidizing flame Hottest part of flame Bright blue reducing flame Page 8 BURNER Operation of the Burner Examine your laboratory burner. Unscrew the barrel and note how the size of the air vents changes. Locate the needle valve at the bottom of the burner which regulates the flow of the incoming gas. To ignite the burner: 1. Adjust the air vents until they are only slightly open. 2. Gently rotate the needle valve clockwise until it is closed (do not apply pressure as you might damage the valve), and then turn it back counterclockwise one full turn. This insures that the gas flow is in the normal range of what you will need for a good flame. 3. Turn the gas on at the gas cock on your lab bench by moving the handle from either of the two "off" positions to the “full on” position (this control should NOT be used for regulating the gas flow). 4. Position the lighter at the top of the burner and ignite. To adjust the flame: 1. The height of the flame can be adjusted with the needle valve at the bottom of the burner. 2. The color of the flame can be adjusted by turning the barrel of the burner clockwise (less air) or counter clockwise (more air). Insufficient air will cause a yellow or orange flame. Increasing the amount of air will cause the flame to become blue and ultimately, when properly adjusted, to develop a bright blue inner cone and a darker blue outer cone. If too much air is admitted, the flame may blow itself out. .