The flint cigarette lighter consists of a thumbwheel which rubs over a flint. The thumbwheel is forced against the flint with the use of a spring. At the end of a stroke, the thumb presses down a lever. This causes gas to be released from an internal reservoir. The spark generated by the flint then ignites the gas jet. As long as the lever remains down, the flame will continue to burn. A flame shield is provided to help prevent the flame from being blown out. When the lighter requires refilling, the gas refill tube is pressed against the needle valve positioned at the base of the lighter. The valve is kept closed by means of a spring but as the filler tube is pushed against it the valve opens allowing the gas to enter the reservoir. Butane cigarette lighters have replaced the old-fashioned petrol types. These had the same flint and thumbwheel arrangement, but it was used to light a wick soaked in petrol.
In the main, only low cost cigarette lighters are manufactured with a flint operation. The more popular piezzo electric lighters are now used more often than not.
The piezzo electric lighter generates a spark with which to light the escaping butane gas. The spark is generated by rubbing together two crystals via a thumb operated button. The spark is then arced from an electrode to the head of the gas release valve igniting the gas and producing the flame.
