Spark igniter for combustion chambers

Claim 2

A spark igniter having an operative end adapted to project into a combustion chamber through a wall thereof surrounded by a cooling fluid, said igniter including an electrode, an insulating core surrounding said electrode, and a tubular sleeve surrounding said core, said sleeve having an outer surface, said outer surface having a plurality of circumferentially spaced axially extending grooves therein, said grooves adapted to lead the cooling fluid from outside of the combustion chamber over said end of said igniter to cool said end.

Claim 3

The igniter according to claim 1 wherein said tubular sleeve comprises a ground shell for said igniter assembly.

Claim 4

An igniter according to claim 2 wherein said ground shell has an end adapted to project into the combustion chamber through an opening in a wall thereof, said end being the operative end of said ground shell, said grooves extending through said end forming slots therein, a portion of each groove adapted to remain outside the combustion chamber for receiving the cooling fluid surrounding the combustion chamber and directing it through said slots to form a cooling film over said end of said ground shell, thereby reducing the temperature of said end and prolonGing its life.

Claim 5

The igniter according to claim 3 wherein one of said slots has a depth greater than at least one other of said slots for providing a better distribution of cooling fluid over the igniter operative end.

Claim 6

The igniter according to claim 4 wherein alternate slots have greater depth.

Claim 7

The igniter according to claim 1 wherein said sleeve is radially spaced from said insulating core for providing an insulating space therebetween to reduce the radial thermal gradient within the core.

Claim 8

The igniter according to claim 6 and wherein said insulating space is a dead air space.

Claim 9

The igniter according to claim 1 wherein said igniter is adapted to operate in an engine utilizing water injection and said tubular sleeve comprises shielding means adapted to prevent water from contacting said core.

Claim 10

The igniter according to claim 8 wherein said sleeve comprises a ground shell for said igniter.

Claim 11

The igniter according to claim 9 wherein said sleeve is radially spaced from said insulating core for providing an annular insulating space therebetween.

Claim 12

A combustor assembly for a gas turbine engine including a combustion chamber, a wall portion surrounding said combustion chamber and radially spaced therefrom to define an annular passageway therebetween adapted to carry a cooling fluid, an igniter having its operative end projecting into said combustion chamber, said igniter including an electrode, an insulating core surrounding said electrode, and a ground shell surrounding said core, said ground shell being radially spaced from said insulating core for providing an annular dead air space therebetween to reduce the radial thermal gradient within the core, said ground shell also including an end projecting into the combustion chamber, said end being the operative end of said ground shell and being in close proximity to said electrode so that during operation a spark may jump therebetween, said ground shell having an outer surface, at least a portion of said surface being within said annular passageway and including a plurality of circumferentially spaced axially extending grooves therein, said grooves extending through said shell end forming slots therein, each groove being adapted to receive cooling fluid surrounding the combustion chamber and to direct it through said slots whereupon it cools said igniter operative end.

Claim 13

A combustor assembly for a gas turbine engine including a combustion chamber, a wall portion surrounding said combustion chamber and radially spaced therefrom to define an annular passageway therebetween adapted to carry a cooling fluid, an igniter having its operative end projecting into said combustion chamber, said igniter including an electrode, an insulating core surrounding said electrode, and a ground shell surrounding said core, said ground shell being radially spaced from said insulating core for providing an annular dead air space therebetween to reduce the radial thermal gradient within the core, said ground shell also including an end projecting into the combustion chamber, said end being the operative end of said ground shell and being in close proximity to said electrode so that during operation a spark may jump therebetween, said ground shell having an outer surface, at least a portion of said surface being within said annular passageway and including a plurality of circumferentially spaced axially extending grooves therein, said grooves extending through said shell end forming slots therein, each groove being adapted to receive cooling fluid surrounding the combustion chamber and to direct it through said slots whereupon it cools said igniter operative end.