Ignition fuse

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Among the igniter is defined as a technical device capable of uncontrolled escape of gaseous or liquid fuels prevented and thus avoids deflagrations or explosions. Ignition fuses have been used primarily in gas appliances since the early 1900s. There are various ways of protecting the ignition.

Bimetal ignition fuse

A bimetallic strip is heated by an ignition flame , which, through its deformation, enables the gas supply. Since it cannot be ruled out that the pilot flame hits the bimetal strip directly, the bimetal can burn out and become ineffective. Therefore, bimetal ignition fuses are not permitted today.

Thermoelectric ignition fuse

Thermal fuse with thermocouple, lead with contact and magnetic switch

Here, a pilot flame in a thermocouple generates an electrical voltage through the heat. This keeps the solenoid valve in the gas valve open. This form of ignition protection is found today in gas stoves, camping and construction site heaters.

Ionization fuse

A flame changes the state of substances such as gases by breaking down neutral molecules into ions . These have an electrically rectifying effect on an applied alternating current, similar to a diode . If an electrical alternating voltage is applied to the burner surface via an electrode, this alternating voltage is rectified by flame ionization and a current of up to about 50 micro amperes (µA) can flow. This current serves as a signal for the automatic firing system , which, together with other signals, evaluates them for plausibility as a function of time. The burner control ultimately controls the solenoid valves of gas fittings or oil pumps.

Optical ignition protection

A photo resistor, flicker detector or infrared detector detects a burning flame and sends it to the burner control as an electrical signal . As with ionization monitoring, this switches solenoid valves.

literature

  • Lajos Joos: Practice of gas application technology in household and trade. Vulkan Verlag, Essen 2002, ISBN 3-8027-3506-4 .
  • F. Göttgens: About the peculiarities of the bimetallic, thermal and flame ionization protection methods in their application to ignition protection, Westdeutscher Verlag, Cologne Opladen.
  • Ernst-Rudolf Schramek, Hermann Recknagel (Hrsg.): Pocket book for heating + air conditioning 07/08. Volume 73, Oldenbourg Industrieverlag, Munich 2007, ISBN 978-3-8356-3104-5 .

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