Multipoint injector for a turbine engine combustion chamber

1. A fuel injector device for an annular combustion chamber of a turbine engine, comprising:

a pilot circuit that continuously feeds an injector leading into a first venturi;

a multipoint circuit intermittently feeding injection orifices opened downstream and formed in a front face of an upstream annular chamber of a second venturi coaxial about the first venturi;

an annular ring mounted in the annular chamber to define therein a fuel feed circuit that feeds the injection orifices and a cooling circuit that operates by passing fuel that feeds the injector of the pilot circuit,

wherein the cooling circuit includes a groove formed in a downstream face of the annular ring in immediate vicinity of the injection orifices, the downstream face of the annular ring being pressed against the front face of the annular chamber.

2. A device according to claim 1 , wherein the cooling circuit further comprises an annular channel formed between inner cylindrical walls of the annular ring and of the annular chamber.

3. A device according to claim 1 , wherein the cooling circuit further comprises an annular channel formed between outer cylindrical walls of the annular ring and of the annular chamber.

4. A device according to claim 3 , wherein the annular channel formed between the outer cylindrical walls of the annular ring and of the annular chamber is configured to be isolated from the pilot circuit and to be filled in operation with air or with coked fuel.

5. A device according to claim 1 , wherein the cooling circuit that cools the front face of the annular chamber is of undulating shape and extends in alternation radially inside and outside the injection orifices.

6. A device according to claim 1 , wherein the cooling circuit that cools the front face of the annular chamber comprises two symmetrical semicircular branches, each extending between a fuel inlet and a fuel outlet means.

7. A device according to claim 6 , wherein the fuel outlet is connected to the injector of the pilot circuit.

8. A device according to claim 1 , wherein the downstream face of the annular ring includes fuel-passing orifices leading into the orifices in the front face of the annular chamber.

9. A device according to claim 8 , wherein the orifices in the downstream face of the annular ring present a diameter that is less than the diameter of the orifices in the front face of the annular chamber.

10. An annular combustion chamber for a turbine engine, the annular combustion chamber comprising at least one fuel injector device according to claim 1 .

11. A turbine engine, a turboprop or a turbojet, comprising at least one fuel injector device according to claim 1 .