US2968152A - Air separator for monofuel burner - Google Patents

Description

E. K. MOORE' AIR SEPARATOR FOR MONOFUEL BURNER Filed Oct. 1, 1956 Jan. 17, 19 1 v luvs/wok EARL K. M0 0RE A r [ORNEV I i i United States Patent AIR SEPARATOR FOR MON OFUEL BURNER Earl K. Moore, Granby, Conn., assignor to United Aircraft Corporation, East Hartford, Conn., a corporation of Delaware Filed Oct. 1, 1956, Ser. No. 613,326

2 Claims. (Cl. 611-3946) This invention relates to an air induction fuel atomizer and more particularly to an air aspirator energized by ejection of a monofuel from an atomizing nozzle to draw air into a combustion chamber and mix it with the injected monofuel.

An object of this invention is mechanism which will draw air into a combustion chamber incident to injection of a monofuel.

A further object is mechanism which will utilize the fuel flow to draw air into a combustion chamber and block the air flow to and combustion gas from the combustion chamber after the fuel has been ignited.

A further object is mechanism which will mix a monofuel with air as it is being introduced into a combustion chamber and then automatically block the air passage upon ignition of the fuel.

A further object is mechanism utilizing the energy in the fuel stream for introducing air into a combustion chamber and utilizing the energy in the fuel for blocking the air passage to the combustion chamber.

Other and additional objects will be apparent from the following specification and the attached drawings in which:

Fig. 1 is a schematic side view partly in section of the air induction fuel atomizer having two fuel injection nozzles.

Fig. 2 is a modification of Fig. 1 showing the device with a single fuel injection and atomizing nozzle.

Fig. 3 is a modification of the device shown in Fig. 2, utilizing a different shutoff valve for the air.

In the ignition and burning of some types of monofuels in a combustion chamber, it has been found that when the device is started after a previous firing, unless the exhaust gases are cleared from the combustion chamber or auxiliary air supplied, difiiculty may be experienced in igniting the monofuel although the monofuel itself contains sufiicient oxidizer to sustain burning after the ignition has taken place.

It has been customary to provide an air purge of the combustion chamber before each firing in order to clear the exhaust gases from the previous firing and introduce a quantity of air necessary for the ignition and initial burning of the monofuel. A separate pump or air pressure source has been used to supply the air to purge the combustion chamber. In order to avoid the necessity for pump purging, this invention utilizes the How of fuel through the nozzle to suck or aspirate air around the nozzle and mix it with the fuel to initiate combustion. After the fuel is ignited, the air passage is blocked by mechanism which is responsive to the increase in pressure in the combustion chamber, indicating that ignition has satisfactorily taken place.

In the embodiment shown in Fig. 1, monofuel is drawn from a fuel supply, not shown, by pump and introduced under pressure to a pipe 12 and a valve 14 and thence to a nozzle 16 from which it is atomized and discharged into a combustion chamber 18. A tube 20 is arranged around nozzle 16 and has a portion 22 ex- 2,968,152 Patented Jan. 17, 1961 "ice tending in the direction of the flow of the discharged fuel of the nozzle 16.

The tubes 20 and 22 form an aspirator WhlCh draws air or oxygen through a valve chamber 24 and an inlet pipe 26 either from the atmosphere or any other suitable supply. Fuel discharged from the nozzle 16 1s atomlzed and mixed with the air drawn through the pipes 20 and 22 and the combined air and fuel is discharged through a nozzle 28 into the combustion chamber 18.

An igniter 30, shown as an electric spark plug but which may be any suitable type of igniter, is energized simultaneously with the discharge of the fuel-air mixture into the chamber 18 and serves to ignite the mixture. The air introduced with the monofuel provides suflicient oxygen in the neighborhood of the fuel to initiate' and sustain combustion even if the chamber were contaminated by burned gases from a previous firing. After the ignition and initial burning of the monofuel, the air supply can be out 01f as the monofuel itself contains sufiicient oxygen or other ingredients to support combustion without the addition of any air or other oxygen from the outside.

A pressure responsive device such as a pressure actuated switch 32 of any well known type may be used to close the circuit from the power source 34 to an electromagnet 36, thus closing switch 38 and energizing electromagnets 40 and 42. Eleotromagnet 40, when energized, will lift valve 44 and block the inlet pipe 26 and tube 20, thus cutting off the supply of air to the aspirator and blocking the flow of any further air to or the escape of combustion gases from the combustion chamber. Energization of electromagnet 42 will move valve 14 to the right as viewed in Fig. 1 and connect the discharge from pump 10 through pipe 46 with a second atomizing nozzle 48 and cut off the How of fuel to the combined atomizing and aspirating nozzle 16.

After ignition is started and pressure is built up in combustion chamber 18, the products of combustion are discharged through a suitable discharge orifice and may be utilized for any desired purpose such as energizing a rocket engine or an engine starter.

Fig. 1 shows an embodiment utilizing the gases in an engine starter having a nozzle 50 directing the combustion gases so as to impinge upon the blades 52 of a turbine wheel 54 which may be used to energize the starter for a turbine-jet or other type of engine.

In the modification shown in Fig. 2, the fuel under 2 pressure in line 12 is led to an atomizing nozzle 56 which is arranged in an orifice 58 of the wall 60, of the combustion chamber 18 to produce the aspirating action. The orifice 58 is connected by a passage 20 with a valve chamber 24 having a valve 44 therein controlling the inlet passage 26. A pressure responsive switch 32 is used to close the valve 44 in the same manner as described in connection with Fig. 1 upon the increase in pressure in tfllilel combustion chamber 18 incident to ignition of the In the modification shown in Fig. 3, the fuel under pressure fro-m pump 10 is led through pipe 12 to the atomizing nozzle 56 in the same manner as described for the modification in Fig. 2. The fuel ejected from the nozzle 56 will aspirate air from the inlet 26 through valve chamber 24 and passage 20 and through orifice 58 in the same manner as described in connection with the device in Fig. 2. In the mechanism of Fig. 3, however, a ball check valve 62 is provided in place of the spring and electromagnetically actuated valve 44 of the device shown in Figs. 1 and 2. Ball check 62 is urged to a closed position by a light spring 64. Upon the start of the injection of fuel, the pressure reduction around the nozzle 56 will cause valve 62 to open against pressure of spring 64 and thus permit the nozzle 56 to thus avoids the necessity for any special power consuming.

device for'purging thechamber prior to ignition.

Although only one embodiment has been shown and described herein, it'will be-apparent that various changes and modifications'may be made in the construction and arrangement of the various parts without departing from the scope ofthis novel concept.

What is desired to be obtained by Letters Patent is:

1. In a system feeding. monofuel to a combustion chamber contaminated with burned gases, an aspirator having an air supply line connecting the atmosphere with said combustion chamber, means discharging said fuel under pressure through said aspirator into said combustion chamber toatomize said fuel and draw air through said line into said combustion chamber and mix said atomized fuel with said air substantially free of said burned gases to provide a relatively easily ignitable mixture and means responsive to the pressurein said combustion chamber, incident to ignition of said discharged fuel, blocking said aspirator air supply line.

4, 2. In combination with means including a nozzle for atomizing and feeding a pressurized monofuel into a burned-gas-contaminated combustion chamber for ignition and burning therein, means for supplying air to said atomized monofuel for the ignition and initial burning of said monofuel comprising an aspirator, energized by the fuel discharge from said"nozz1e, for drawing air into said combustion chamber and mixing the air with said atomized fuel, means connecting said aspirator with a supply of air at a pressure'lower than said fuel, a'valve in said connecting means, and means responsive to a pressure rise in said combustion chamber incident to ignition of said fuel andwhilefuel is being fed to said combustion chamber for closing said valve and blocking said connecting means.

References Cited in the file of this patent UNITED STATES I PATENTS 2,542,953 Williams Feb. 20, 1951 2,574,495 Parker Nov. 13, 1951 2,599,480 Pfenninger June 3, 1952 2,815,271 Zwicky et a1. Dec. 3, 1957 2,858,672 Clark Nov. 4, 1958 2,863;283" Schmider et' a1. Dec. 9, 1958 FOREIGN PATENTS 1,042,673 France" June'IO, 1953 660,178 Great Britain Oct. 31, 1951

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