GB832992A - Improvements in spark discharge ignition systems - Google Patents

Abstract

832,992. Ignition systems. ELCONTROL Ltd. Oct. 23, 1957 [Oct. 24, 1996], No. 32391/56. Class 7(4) In an ignition system a main storage condenser, C 1 and/or C 2 adapted to be charged from a suitable voltage source and discharged through a spark gap G- for example of the surface discharge type -has normally open electromagnetically operated relay contacts A 1 in the discharge circuit thereof, and the operating coil A 2 of the relay is connected across the storage condenser through an electronic switch device (neon tube N) the break down potential of which is thereby derived from the the main condenser, whilst a breakdown control circuit associated with the switch determines the instant of breakdown thereof. As shown, the breakdown control circuit includes a time delay condenser C 3 . The contacts a 2 close at the same time as the contacts a 1 and discharge the condenser C 3 . The frequency of repetition of sparking is determined by the size of the time delay condenser C 3 and the values of the resistances R, and R 2 . Hence by varying the position of the tapping point P or the size of the time delay condenser C 3 the sparking frequency can be controlled. Other 'kinds of electronic switch than a neon tube or like glow discharge diode may be used such as a hard valve or a grid controlled gas discharge tube. In this case the timing condenser C a may be replaced by some form of triggering circuit connected to the control grid. In this way a definite programme of discharges may be set up having no constant. repetition'frequency or a manual control may be arranged so that discharge occurs at will. If the electronic switch is a grid-controlled electron discharge tube the breakdown interval may in part be a function of the voltage time characteristic of the control grid circuit. This characteristic may be a step or ramp function the former being represented by say manual or time switch controlled contacts and the latter by say a constant speed potentiometer connected across a source of bias voltage. The gap G is optionally shunted by a resistance R 4 . The Specification refers to the application of the system to burner and furnace igniters where photo-electric flame failure protection is installed.