US2920450A - Igniter - Google Patents

Description

Jan. 12, 1960 c, E, SEGLEM 2,920,450

, IGNITER Filed Sept. 1'7, 1954 INVENTOR.

CLIFFORD E. SEGLEM ATTO NEYS United States Patent IGNITER Clifford E. Seglem, Wallingford, Pa., assignor, by mesne assignments, to the United States of America as represented by the Secretary of the Navy Application September 17, 1954, Serial No. 456,895 1 Claim. (Cl. 60-39.82)

This invention relates to igniters for fuel burners and more especially to igniters which burn heavy fuel oil and are adapted to ignite fuel burners of gas engines which are supplied by heavy fuel oil.

Gas engines such as gas turbines and jet engines present problems in starting which are not present in other engines. Such engines must start under various interior pressures and temperatures and under a strong flow of the air or other gases which are to be heated to operate the engine. The ignition must be positive so that the fuel is ignited immediately when it enters the burner. Failure in the ignition passes fuel into the after parts of the engine where it may cause an explosion.

For example, gas turbines usually have a number of burners commonly known as flame tubes. Failure in the timely ignition in one of the flame tubes passes the unburned fuel oil into the after part of the engine. This fuel may then be ignited by the other flame tubes and may explode in the engine.

The seriousness of this problem is intensified where gas engines operate on low volatile fuel oil and where the igniters use fuel of the same type to avoid the need of a separate fuel supply.

it is an object of the invention to provide a positively acting igniter for burners.

It is another object of this invention to provide an igniter which burns low volatile fuel oil and which is adapted to ignite the burners of a gas engine fired by the same type of fuel oil.

Other objects and advantages of the invention will here, inafter become more fully apparent from the following description of the annexed drawings, which illustrate a preferred embodiment, and wherein:

Fig. l is a sectional view of the igniter of this invention positioned on the flame tube of a gas turbine;

Pig. 2 is a sectional view on the line 2-2 of Fig. 1.

Referring now to the drawings for a description of the invention, the reference numeral designates a metal tube which communicates at one end with a flame tube 12. The other end of the tube 10 is closed by a metal block 14. An angle bore 16 is formed in the block 14 which bore 16, at its outlet end, connects with one leg 17 of a U-shaped metal tube 18 positioned in the tube 10. The other leg 22 of the U-shaped tube 18 connects with a larger tube 24 which extends towards the block 14. The tube 24 encloses one end of a heating element 26 of heating plug 28 which extends through a threaded opening 30 in the block 14.

A T-shaped coupling 32 forms a carburetor and connects at its outlet end 34 with the bore 16. The inlet 36 end of the coupling 32 connects with the outlet end 34 thereof through a restricted pasage 38. A smaller bore 40 connects the restricted passage 38 with a fuel inlet end 42 of the T-shapcd coupling 32.

2,920,450 Patented Jan. 12, 1960 A spark plug 44 projects through a screw threaded opening 46 into the tube 10 at a point adjacent the larger tube 24. 4

In the operation of the device, the fuel inlet42 of the coupling 32 is connected to a fuel reservoir (not shown) of diesel or fuel oil and the air inlet 36 to a supply of compressed air. The heating plug 28 and the spark plug 44 are then energized and the compressed air is admitted to the coupling 32 through the inlet 36. This aspirates fuel from the reservoir through the tube 40 and mixes the fuel with the air to form a spray. The spray enters the U- shaped tube 18 and passes through tube 24 over the heating element 26 which vaporizes a portion of the fuel oil. This vapor is ignited by the spark plug 44 producing an initial flame in the igniter. This flame travels back to the tube 24 and extends downwardly in the tube 10 thereby heating and vaporizing the fuel spray in the U-shaped tube 18. This vapor augments the flame at the mouth of the tube 24 and further heats the tube 18 when the flame is deflected by closure 14 over the tube and through the outlet of the housing into the combustion chamber. When the flame is started, the heater plug 28 and the spark plug 44 may be deenergized. The flame in the tube 10 will gradually become hotter and extend into the flame tube 12.

The flame tube 12 already carries a strong flow of air;

The fuel supply (not shown) of the flame tube 12 may now be turned on and will be ignited instantly by the hot flame shooting forth from the tube 10.

It will be apparent from the above that this invention produces an igniter adapted to utilize a low volatile fuel and in a short period of time to produce a hot flame which will positively ignite a burner using similar fuel oil.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claim the invention may be practiced otherwise than as specifically described.

What is claimed is:

An ignition device adapted for the instantaneous combustion of reactants within a combustion chamber which comprises a housing having one open end in communication with the, combustion chamber and a closed end disposed exteriorly thereof, said housing providing an elongate ignition chamber between said ends, supply means adjacent the closed end of and communicating with the housing for the admission of the air-fuel mixture, a generally U-shaped preheater tube within the housing and extending substantially the length thereof, said preheater tube having an inlet end in communication with said supply means and an open outlet end spaced axially from its inlet end, said outlet end of the tube providing a space with the closed end of the housing, heating means extend- References Cited in the file of this patent UNITED STATES PATENTS 2,522,081 Allen Sept. 12, 1950 FOREIGN PATENTS (1st addition to Nd. 687,675)

France Jan. 7, 1931

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