Patent ID: 6676404
Filing Date: 2004-01-13
Classification: F23N

Abstract:
A measuring device for a flame produced by a burner, in particular for use in a regulating device for the burner, comprising:an ionization electrode which is positionable in the flame region of the burner; means for applying an ac voltage component to said ionization electrode, said ac voltage component being influenced by the resistance of the flame; means for superimposing a dc voltage component on said ac voltage, said dc voltage component being dependent on the ionization current; a first filter for separating said ac component from said superimposed dc and ac voltage components; a second filter for separating said dc voltage component from said superimposed dc and ac voltage components; and means for comparing said separated ac voltage component and said separated dc voltage component to produce a pulse width-modulated signal when a flame is present, the duty factor of said pulse width modulated signal being indicative of flame resistance.