Igniter in starter for low pressure discharge lamps - where igniter bulb contains inert gases, hydrogen, and radioactive krypton

摘要

The lamps contain electrodes which can be preheated; and the igniter consists of a discharge bulb contg. two bimetal electrodes (a, b) located opposite each other and each fitted with a contact (a1, b1). The bulb contains a mixt. of 50-75 vol. % He, 20-40 vol. % Ar, 1-10 vol. % H2, with a filling pressure (FP) of 25-80 mbar, and 1-3 mCi of krypton-85/normal litre. The Kr-85 provides pre-ionisation. The contact discs (a1, b1) pref. contain by wt. 20-70%, esp. 60% Ag, with 30-80%, esp. 40% Ni, as a composite fibre material. The FP is pref. 40-50 mbar using by vol. 65% He, 30% Ar, 5% H2 plus 2 mCi Kr-85/normal litre. Used esp. to lower the peak voltage in a rapid safety starter described in DT 2321212, but with adequate heating of the lamp electrodes.