GB768422A - Improvements in or relating to injector ignitor plugs for gas turbine engines - Google Patents

Abstract

768,422. Sparking plugs. GENERAL MOTORS CORPORATION. April 18, 1955 [April 30, 1954], No. 11080/55. Class 7 (4). [Also in Group XI] An igniter tor gas turbine engines comprises a bifurcated electrode 33 mounted co-axially in an insulator 29 sealed into a tubular shell 3 and a ring-shaped counter-electrode 38 secured to the lower part of the shell and adapted to store heat for igniting the fuel after the spark has been switched off. The insulator 29 is secured within the shell by crimping the upper edge of the shell over an upper shoulder 43 on the insulator so as to stress an annular steel C-spring 47 placed between a lower shoulder 45 on the insulator and a ledge 25 at the upper end of a frustoconical passage 21 in the shell. Compressed air is delivered through a metering and pressure reducing orifice 55 in a plate in an inlet in the shell to an annular passage formed between the shell, the insulator and the C- spring and passes through to bores in the shell opposite the air inlet to an annular chamber 66 formed by a flanged collar 59 seated on the frusto-conical passage 21 in the shell. Part of the air is discharged helically through apertures 67 in the collar 59 into the lower part of the shell to mix with atomized fuel discharged from a nozzle 79 located in a bore in the shell, and another part of the air is directed upwardly through apertures 69 in the collar 59 to pass over the inner surface of the C-spring, between the knurled top 61 of the collar 59 and the C-spring and downwardly through the annular passage 71 between the collar and the insulator tip 62.