Safety system

May 19, 1964 j. _{c GA}rr_Ett 3,133,667

SAFETY SYSTEM

Filed March 10, 1959 2 Sheets-Sheet 1

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ATTORNEY

May IS, 1964

J. C. GARRETT

SAFETY SYSTEM'

3,133,667

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United States Patent Office _Patented to the following detailed description and accompanying drawings wherein:

FIGURE 1 is a diagrammatic view partly in section showing a safety device embodying the present invention 5 applied to a fuel system and associated engine;

FIG. 2 is a detailed sectional view taken through a portion of the device shown in FIG. 1 on the plane indicated by the line 2—2 of such figure; and

FIGS. 3, 4 and 5 are diagrammatic views illustrating 10 slight variations of the invention.

Referring more particularly to FIG. 1 of the drawings, it will be seen that the safety system forming the subject matter of the invention has been illustrated in one of its many applications. In this figure the safety sys15 tern is applied to a power generating unit including a gas turbine engine and its associated fuel system. The engine may serve as a gas generator or produce pneumatic or shaft power as required. It is to be understood at this point that the safety system comprising the invention may 20 be applied to any type of engine and fuel system or any components thereof which receive combustible fuel and are apt to leak and create the hazard of an explosion.

The safety system shown in FIG. 1 includes a casing or envelope 1 which is formed to receive and support a 25 gas turbine, or any other type of engine, 2 and its asso- ciated fuel system designated generally by the numeral 3. Fuel system 3 includes a reservoir 4, a pump 5, and piping 6 through which the fuel is drawn from the reservoir and supplied to the engine in the usual manner. Other 30 necessary or desired fuel system components may be provided to control the operation of the engine.

The safety system is provided to reduce or eliminate the dangers of explosions resulting from leakage of fuel from the reservoir or other fuel system components. In35 take and exhaust passages 7 and 8, respectively, are provided to admit air from the ambient atmosphere to the engine and conduct gases of combustion therefrom.

Casing 1 is provided to enclose the engine and fuel system and catch any fuel leaking from the system. To 40 reduce the danger of the leakage thus collected from combining with air and producing an explosive mixture, it is proposed to charge the envelope 1 with an inert medium, such as helium. This objective is attained by providing a container 1® of the inert fluid and connecting the outlet 45 of the container with the interior of the envelope by a line 11. A suitable pressure responsive valve 12 is disposed in the line 11. After the engine and fuel system are assembled in the envelope 1 and the outlet of the container is opened, valve 12 will admit sufficient inert ⁵⁰ medium to charge the interior of the envelope to a predetermined pressure above atmospheric pressure to preclude the entrance of air at such pressure. Leakage from the reservoir 4, the pump 5, or any other part of the system will combine with the inert fluid to preclude, as much ⁵⁵ as possible, the formation of an explosive mixture.

As a further protection against explosions, the envelope 1 is provided with an outlet passage in the form of a tube 13 which extends from a small dome-shaped vapor trap 14 disposed at the top of the envelope. This trap is so ⁶⁰ located because of the tendency of lighter gases to rise; the trap is in open communication with the interior of the casing. Tube 13 leads to an outlet fitting 15 provided at one side of and communicating with the turbine exhaust passage 8. It will be obvious that as the pressure in65 creases within the envelope, gaseous fluids contained therein will tend to flow through the tube to the outlet fitting and escape to the atmosphere via the exhaust passage 8. To prevent waste of the inert medium, the outlet fitting may be provided with a pressure responsive relief valve 70 16 of any suitable type which will be adjusted to prevent flow through tube 13 and outlet fitting 15 until a predetermined pressure, above that for which valve 12 has

3,133,667

SAFETY SYSTEM

John Clifford Garrett, Beverly Hills, Calif., .assignor to The Garrett Corporation, Los Angeles, Calif., a corporation of California

Filed Mar. 10,1959, Ser. No. 798,428

Claims. (Cl. 220—88)

This invention relates generally to safety means and is more particularly directed to a system for preventing accidental explosions due to leakage from a fuel system or its components.

A basic safety system embodying the present invention includes means forming a sealed envelope for enclosing a fuel system and other associated apparatus and collecting leakage therefrom, the envelope being provided with means for disposing of the fuel leakage in a safe manner. Modifications of the invention may include means for introducing an inert medium into the envelope to combine with the leakage, means forming an outlet which establishes communication between the interior and exterior of the envelope, and means operative to regulate the flow of the inert medium containing fuel leakage through such outlet. Means may also be provided to consume or bum the fuel in the escaping medium, as it passes from the outlet, to reduce the possibility of an explosion and to salvage the energy in the fuel thus discharged. Since it is important to constantly maintain a completely inert atmosphere in the envelope, a reservoir containing inert matter and means to conduct and regulate flow therefrom into said envelope may be provided, when appropriate, to- replace any loss of the inert matter from the envelope.

It is an object of the present invention to provide a safety system comprising means forming a sealed envelope for enclosing a fuel system and collecting fuel leakage therefrom, means being provided in connection with the envelope to dispose of the leakage before a dangerously explosive amount can accumulate.

Another object of this invention is to provide a safety system having a casing for enclosing a fuel system, the casing being provided with means for supplying the interior thereof with an inert medium, the casing also being provided with an outlet including an ignition device to permit the controlled discharge and burning of any fuel which may have leaked from the fuel system and been combined with the inert medium.

Another object of this invention is to provide a safety device having a fuel system disposed in a casing containing an inert medium, the casing being formed with an outlet having a flow control mechanism therein whereby the outflow of inert fluid and fuel from the interior of the casing will be regulated according to a predetermined schedule based on the amount of leakage from the fuel system.

A further object of this invention is to provide a safety device of the type having a feul system and associated apparatus enclosed in a casing containing an inert medium, reservoir means containing inert matter being provided to operatively communicate with the interior of the casing for replacing inert matter according to a predetermined schedule based on the amount of leakage from said casing.

A further object of the present invention is to provide a safety device of the type having a fuel system and an engine disposed in a casing. In this device the engine component thereof includes intake and exhaust means which communicate with the exterior of said casing, the fuel system thereof communicating with the engine via passages contained in the casing; thus leakage from the fuel system will be confined to the casing and may then be disposed of by burning in a predetermined safe region.

Other objects and advantages of the invention will become apparent to persons skilled in the art by reference

3,133,667 been set, is reached in the envelope 1. This increase in pressure may be caused by the escape of fuel under a pressure exceeding that of the inert medium in the envelope. When valve 16 opens and a mixture of fuel leakage and inert medium flows into the outlet fitting 15, the 5 mixture will be discharged into the exhaust gas stream where it will be safely burned.

Still further protection may be secured by providing the outlet fitting 15 with a burner 17 adjacent the downstream side of the valve 16. Burner or pilot ignitor 17 10 may also be of any suitable type, the one shown in FIG. 1 projecting into the fitting 15 and communicating with a line 18 which, in turn, is connected with the fuel system 3. It should be obvious that if it is desired or found necessary to maintain operation of the pilot burner 17 15 when the engine 2 or its fuel system is not in operation, a separate source of fuel or an electric ignition device could be provided without departing from the concept of this invention. To sustain the ignition of fuel supplied to the burner 17, air may be conducted to the burner from the 20 engine plenum through a line 20. Thus, when a mixture containing fuel issues from the tube 13 through valve 16, the fuel will be ignited by the flame from the burner 17, and safely burned in the exhaust passage.

To summarize the operation of the safety system shown 25 in FIG. 1 it may be stated that following the assembly of the engine and fuel system in the envelope 1, the interior of the latter is purged of air, or other combustion supporting medium, and then charged with inert gas from the container IQ. When the pressure for which valve 12 30 has been set is reached, the flow of inert gas into the casing 1 will cease. The reservoir 4 is then filled with the desired fuel and the engine may be operated. If the fuel system has been properly constructed and remains in good condition, the safety system will be inoperative. If, however, 35 fuel should leak from the fuel system, the leakage will combine with the inert gas and the formation of a combustible mixture will be prevented. Continued leakage will cause the pressure in the envelope 1 to rise until valve 16 opens and permits the combined fuel and inert gas to 40 escape to the exhaust passage S. The fuel will be burned in the exhaust gases. If the safety system is provided with the pilot burner 17, the fuel in the escaping mixture will be burned regardless of whether any exhaust gases are flowing from the engine. 45

While a unitary safety system for protecting an entire engine and fuel system has been shown in FIG. 1, it will be apparent that separate systems could be provided for the various components of a fuel system, such as the fuel storage tank, the pump, the engine, the controls, and other 50 parts. For example, FIGS. 3, 4 and 5 illustrate features of the invention applied to heat exchangers which may be employed in a fuel system. In FIG. 3, the heat exchanger 21 is enclosed in a casing 22 to collect fuel leakage therefrom. The casing communicates with an inlet 55 23 for a suitable medium and an outlet passage 24. The latter is provided with an exhaust fan 25 so that the suitable medium may be drawn through the inlet 23, swept over the exterior of the heat exchanger 21, and exhausted through the outlet passage 24 to a suitable region where 60 burning of the fuel may safely be performed.

In FIG. 4, the heat exchanger 25' is also enclosed in a casing 26 which is provided with an outlet passage 27 only. This passage is also provided with an exhaust fan 28 by which a partial vacuum may be maintained in the 65 casing 26. If fuel should leak from the heat exchanger, it will be drawn from the casing 26 as fast as it flows in and may be consumed by the flame of a burner 30 placed in a suitable safe region downstream of the fan 28.

FIG. 5 illustrates a heat exchanger 31 enclosed in a casing 32 which is provided with one or more ignitors 33. The latter elements are constantly energized and serve to cause the burning of leakage as fast as it occurs, thus preventing the accumulation of a large combustible mixture which might cause a serious explosion.

The invention has been illustrated in some of its simplest forms, but it should be understood that the configuration and arrangement of parts may be widely varied without departing from the spirit and scope of the invention, as herein shown and described.