Abstract: An igniter plug having a center conductor, an insulator and a conductive outer shell. The insulator surrounds and supports the center conductor axially within the shell along a substantial portion of the length of the center conductor. The insulator is of reduced diameter toward the discharge end of the igniter and terminates short of the full length of the center conductor. The center conductor extending beyond the insulator terminates short of the discharge end of the igniter and has a discharge electrode of greater diameter than the center conductor affixed to the center conductor end. The electrode terminates at the discharge end of the igniter. A helical compression spring is fitted over the center conductor between the end of the insulator and the electrode to absorb vibrations of the center conductor and electrode.

Abstract: A spark discharge igniter for gas turbine engines and the like. The igniter includes a tubular metal shell and a relatively long ceramic insulator inserted in the shell and rigidly secured to the shell near one end thereof. A metal collar is fitted tightly between the insulator and shell at the end opposite the rigidly secured end. The collar is initially in the form of a split ring installed on the insulator prior to assembly of the insulator into the shell. The ring is extruded into the tightly fitting collar in the course of inserting the insulator into the shell.

Abstract: A fuel ignition plug (10) includes an outer electrode (12) defined by a conductive shell which surrounds a central electrode (28) and an insulator body (22) between the central electrode (28) and outer electrode (12). Fused glass powder seals (40,42) between the shell and the insulator body (22), and between the insulator body (22) and the central electrode (28), prevent combustion gasses from passing through the interior of the device (10). The device (10) is assembled by holding the electrodes (12,28) and insulator body (22) in fixed, concentric relationship with each other while the seals (40,42) are heated and extruded into sealing position against a shoulder (38,52) of the insulator body (22). The seals (40,42) are extruded into sealing position by applying force to push rings (44,46) which are respectively sleeved over the insulator body (22) and central electrode (28) and bear against the seals (40,42).

Abstract: A method of making a tubular electrical insulator assembly for an igniter plug comprising the steps of making a recess (11) in one end of a tubular insulator (10); cementing a portion of a tubular semi-conductor (20) into the recess (11) so that the remaining portion of said semi-conductor (20) extends slightly beyond the end of said insulator (10); and grinding an annular chamfer (21) into the ends of the insulator (10) and semi-conductor (20).

Abstract: An igniter plug having a center conductor, an insulator and a conductive outer shell. The insulator surrounds and supports the center conductor axially within the shell along a substantial portion of the length of the center conductor. The insulator is of reduced diameter toward the discharge end of the igniter and terminates short of the full length of the center conductor. The center conductor extending beyond the insulator terminates short of the discharge end of the igniter and has a discharge electrode of greater diameter than the center conductor affixed to the center conductor end. The electrode terminates at the discharge end of the igniter. A helical compression spring is fitted over the center conductor between the end of the insulator and the electrode to absorb vibrations of the center conductor and electrode.