Aircraft fuel tank explosion-proof system and aircraft

Abstract

The invention provides an aircraft fuel tank explosion-proof system and an aircraft, in the system, a gas release lock mechanism is installed at a bottle opening of an inerting gas bottle, the gas release lock mechanism is provided with three outlets which are respectively connected with a filter, a gas outlet and a three-way one-way valve, and a pipeline warmer is arranged on a pipeline between the gas release lock mechanism and the filter; the filter is connected to an inlet of the pressure reducer, and the pressure reducer is mounted in the pressure reducer heating box; the pressure reducer is provided with two outlets, one outlet is connected with an inlet of the small-flow electromagnetic valve through a guide pipe via the flow-limiting warmer, and the other outlet is connected with an inlet of the large-flow electromagnetic valve through a guide pipe. An outlet of the small-flow electromagnetic valve is connected with one sedimentation tank, the one-way valve and the nozzle through pipelines; and an outlet of the large-flow electromagnetic valve is connected with the other sedimentation tank, the one-way valve and the floater valve through pipelines. High-pressure air does not need to be introduced from the engine and the outside, so that the engine power and the use of an environment control system are not influenced; the system is simple in structure, light in weight and low in use cost.

Description

Technical Field

[0001] The invention belongs to the field of aviation technology fire protection technology, and in particular relates to an aircraft fuel tank explosion-proof system and an aircraft. Background Art

[0002] During the flight, the fuel tank of an aircraft may catch fire or explode due to lightning strikes, fuel pump failures, electrical short circuits, static sparks, etc. The fire and explosion of the aircraft fuel tank directly and seriously threaten the safety of the aircraft and its passengers.

[0003] There are many methods for preventing explosions in fuel tanks of aircrafts. Generally speaking, they can be divided into two categories: one is passive explosion suppression measures, i.e. filling explosion suppression materials in the fuel tank, such as filling mesh polyurethane foam materials (explosion suppression foam) or aluminum foil nets. Although passive explosion suppression measures can provide effective protection for aircraft fuel tanks, their fillers (explosion suppression foam, aluminum foil nets) have the problems of increasing weight, reducing oil carrying capacity, accumulating static electricity, aging prematurely, short replacement cycle, and poor economic benefits; the other is active explosion suppression measures, i.e. controlling the oxygen concentration in the gas phase space above the fuel tank by inert gas to achieve the purpose of fire prevention and explosion suppression. The active explosion suppression method mainly adopts the onboard nitrogen-generating fuel tank inerting system, inerting the high-temperature and high-pressure air introduced from the aircraft engine into high-concentration nitrogen through the bleed air heat dissipation and air separation device installed on the aircraft, and filling it into the aircraft fuel tank, so that the oxygen concentration in the oil-free space gas layer above the fuel tank is always kept lower than the level required to support fuel combustion during the entire flight. Currently, active explosion suppression measures are commonly used. However, because the system needs to draw air from the engine, large flow rates have a certain impact on the engine power and the use of the environmental control system. In addition, since the working principle of the airborne nitrogen tank inerting system involves air drawing, heat dissipation, air separation, flow distribution, system control and other aspects, it has shortcomings such as complex structure, heavy weight and high cost of use. Summary of the invention

[0004] In order to solve the technical problems that active explosion suppression measures in the prior art have complex structures, heavy weights, high use costs, and the system needs to draw air from the engine, which has a certain impact on the use of the engine power and environmental control system under large flow, the present invention provides an aircraft fuel tank explosion-proof system and aircraft, which does not need to introduce high-pressure air from the engine and the outside, and will not affect the use of the engine power and environmental control system; and the system has a simple structure, light weight, and low use cost; in addition, compared with passive explosion suppression measures, it does not affect the fuel tank's oil capacity. The technical solution is as follows:

[0005] In a first aspect, an aircraft fuel tank explosion-proof system is provided, comprising: an inert gas bottle 1, a filter 4, a pressure reducer 5, a pressure reducer heating box 6, a small flow solenoid valve 8, a large flow solenoid valve 9, a sedimentation tank 10, a one-way valve 12, a float valve 13, a nozzle 14, a venting port 15, and a three-way one-way valve 16. Inert gas is stored in the inert gas bottle 1. A gas release lock mechanism 2 is installed at the bottle mouth of the inert gas bottle 1. The gas release lock mechanism 2 is provided with three outlets, which are respectively connected to the filter 4, the venting port 15, and the three-way one-way valve 16 through pipelines. A pipeline heater is provided on the pipeline between the gas release lock mechanism 2 and the filter 4. 3, the filter 4 is connected to the inlet of the pressure reducer 5 through a pipeline, and the pressure reducer 5 is installed inside the pressure reducer heating box 6; the pressure reducer 5 is provided with two outlets, one is connected to the inlet of the small flow electromagnetic valve 8 through a conduit via a current limiting heater 7, and the other is connected to the inlet of the large flow electromagnetic valve 9 through a conduit; the outlet of the small flow electromagnetic valve 8 is connected to a sedimentation tank 10, a one-way valve 12, and a nozzle 14 through a pipeline, and the outlet of the large flow electromagnetic valve 9 is connected to another sedimentation tank 10, a one-way valve 12, and a float valve 13 through a pipeline; an oil drain switch 11 is installed at the bottom of each sedimentation tank 10, and the outlet of the three-way one-way valve 16 is connected to the aircraft fire extinguishing system.

[0006] The gas release lock mechanism 2 is electrically connected to the onboard 28V power supply, and the opening or closing of the gas release lock mechanism 2 is controlled by the onboard 28V electrical signal.

[0007] Furthermore, the gas release lock mechanism 2 is provided with a safety film. As the ambient temperature of the inert gas in the inert gas bottle 1 increases, the pressure also increases accordingly. When the temperature of the inert gas in the inert gas bottle 1 is higher than a preset value and the pressure reaches a preset pressure, the safety film ruptures and the inert gas is guided to the vent 15 through a conduit, thereby avoiding safety problems caused by the increase in the pressure of the inert gas in the bottle.

[0008] Wherein, the pipeline heater 3 comprises:

[0009] Stainless steel conduit,

[0010] Glass varnished cloth wrapped around stainless steel conduit;

[0011] Resistance wire wrapped around glass varnished cloth;

[0012] Plexiglas varnished cloth and thermal insulation pad wrapped around the resistance wire.

[0013] The function of the pipeline heater 3 is to energize its resistance wire to heat the conduit when the inert gas is used, so as to prevent the inert gas such as carbon dioxide from absorbing heat when releasing liquid into gas, causing the pipeline to freeze and block.

[0014] Furthermore, a metal filter is installed inside the filter 4 for filtering mechanical impurities in the inert gas to prevent the impurities from entering the oil tank.

[0015] Further,

[0016] The current limiting heater 7 is provided with a resistance wire for heating the pipeline to prevent the current limiting nozzle from being blocked due to ice formation when the inert gas is released.

[0017] in,

[0018] The small flow solenoid valve 8 consists of a DC electromagnet and a direct-acting valve. The DC electromagnet is equipped with a micro switch, which is connected to the indicator light on the machine. When the DC electromagnet is energized, the direct-acting valve is pulled up to connect the air path. When the DC electromagnet is de-energized, the direct-acting valve returns to the normally closed state.

[0019] Optionally,

[0020] The number of inert gas bottles 1 is determined according to the volume of the aircraft fuel tank or the flight time.

[0021] in,

[0022] When filling the inert gas, every two gas cylinders are controlled and released simultaneously as a group. After one group of gas cylinders is released, the next group is opened, which can meet long-term explosion-proof requirements.

[0023] In a second aspect, an aircraft is provided, comprising the aircraft fuel tank explosion protection system as described in any one of the first aspects.

[0024] The beneficial effects of the present invention are at least:

[0025] The invention provides an aircraft fuel tank explosion-proof system, which realizes the fuel tank explosion-proof function by filling the fuel tank with inert gas, and the system weight is small, and does not affect the fuel tank oil capacity; inert gas bottles are used to load inert gas, and there is no need to introduce high-pressure air from the engine or the outside for inerting, the system structure is simple, the use cost is low, and there is no influence on the use of the engine; the system can set the number of gas bottles according to different fuel tank volumes and flight times, and can adjust the inflation flow rate, and has good versatility. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the structure of an aircraft fuel tank explosion-proof system of the present invention;

[0027] Figure 2 Schematic diagram of the gas release lock mechanism of the present invention.

[0028] Among them, 1. Inert gas bottle, 2. Gas release lock mechanism, 3. Pipeline heater, 4. Filter, 5. Pressure reducer, 6. Pressure reducer heating box, 7. Current limiting heater, 8. Small flow solenoid valve, 9. Large flow solenoid valve, 10. Sedimentation tank, 11. Oil drain switch, 12. One-way valve, 13. Float valve, 14. Nozzle, 15. Vent, 16. Three-way one-way valve. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below through specific implementation modes and drawings.

[0030] See also Figure 1 An embodiment of the present invention provides an aircraft fuel tank explosion-proof system, which includes an inert gas bottle 1, a gas release lock mechanism 2, a pipeline heater 3, a filter 4, a pressure reducer 5, a pressure reducer heating box 6, a current limiting heater 7, a small flow solenoid valve 8, a large flow solenoid valve 9, a sedimentation tank 10, an oil discharge switch 11, a one-way valve 12, a float valve 13, a nozzle 14, a vent port 15, and a three-way one-way valve 16.

[0031] For example, the system may include two inert gas bottles 1, each of which is equipped with a gas release lock mechanism 2 at its bottle mouth. The gas release lock mechanism 2 has three outlets, which are respectively connected to a filter 4, a vent port 15, and a three-way one-way valve 16 through pipelines. A pipeline heater 3 is provided on the pipeline between the gas release lock mechanism 2 and the filter 4.

[0032] The filter 4 is connected to the inlet of the pressure reducer 5 through a pipeline, and the pressure reducer 5 is installed in its entirety inside the pressure reducer heating box 6 .

[0033] The pressure reducer 5 has two outlets, one of which is connected to the inlet of a small flow electromagnetic valve 8 through a conduit via a current limiting heater 7, and the other is connected to the inlet of a large flow electromagnetic valve 9 through a conduit.

[0034] The outlet of the small flow electromagnetic valve 8 is connected to a sedimentation tank 10, a one-way valve 12, and a nozzle 14 through a pipeline; the outlet of the large flow electromagnetic valve 9 is connected to another sedimentation tank 10, a one-way valve 12, and a float valve 13 through a pipeline.

[0035] An oil drain switch 11 is installed at the bottom of each sedimentation tank 10 .

[0036] The pipeline after the three-way non-return valve 16 leads to the aircraft fire extinguishing system.

[0037] The system in the embodiment of the present invention has three functions:

[0038] 1) Normal explosion-proof of the fuel tank. Fill the aircraft fuel tank with a small flow of inert gas to control the oxygen concentration in the oil-free space in the fuel tank to a level that cannot burn.

[0039] 2) Explosion prevention during aircraft descent. When the aircraft is in emergency descent, the atmospheric pressure increases sharply. A large flow mode is used to fill the aircraft fuel tank with a large flow of inert gas to ensure that the pressure difference between the inside and outside of the fuel tank remains unchanged.

[0040] 3) Auxiliary fire extinguishing function. When a fire occurs on an aircraft, after the fire extinguishing agent is released, a large amount of inert gas is released into the fire extinguishing pipeline in a short time to realize the fire extinguishing function again.

[0041] Specifically, the working mode of the aircraft fuel tank explosion-proof system of the embodiment of the present invention is as follows:

[0042] (1) Normal explosion-proof of fuel tank:

[0043] Inert gas such as carbon dioxide fire extinguishing agent is stored in the inert gas bottle 1, and the bottle is filled with 5kg of liquid carbon dioxide with a pressure of 15-16MPa. A gas release lock mechanism 2 is provided on the inert gas bottle 1, and the gas release lock mechanism 2 is threadedly installed on the bottle mouth of the inert gas bottle 1. The on-board power supply provides a 28V electrical signal to control the opening of the gas charging passage of the gas release lock mechanism 2. The gas passes through the pipeline heater 3, the filter 4, the pressure reducer 5, the current limiting heater 7, the small flow electromagnetic valve 8, the sedimentation tank 10, the one-way valve 12, and the float valve 13 in sequence to reach the aircraft fuel tank, and each fuel tank is filled with inert gas.

[0044] In the embodiment of the present invention, the number of inert gas bottles 1 can be adaptively increased or decreased according to the volume of the aircraft fuel tank or the flight time. When filling the inert gas, every two inert gas bottles 1 are connected in parallel as a group, and are controlled and released at the same time. After one group of inert gas bottles 1 is released, the next group is opened, so as to meet the long-term explosion-proof requirements.

[0045] The gas release lock mechanism 2 is provided with an inflation electrical control component and a fire extinguishing electrical control component. The gas release lock mechanism 2 is provided with two independent electrical control components for inflation and fire extinguishing. The inflation electrical control component and the fire extinguishing electrical control component are respectively connected to the onboard power supply through control lines. When it is necessary to fill the fuel tank with inert gas, a 28V electrical signal is provided by the onboard power supply to control the inflation electrical control component of the gas release lock mechanism 2 so that the inflation passage is opened. When it is necessary to fill the fire extinguishing system with inert gas, a 28V electrical signal is provided by the onboard power supply to control the fire extinguishing electrical control component of the gas release lock mechanism 2 so that the fire extinguishing passage is opened. Figure 2 .

[0046] Also, see Figure 2The pressure relief port of the gas release lock mechanism 2 is also provided with a safety film. As the inert gas such as carbon dioxide in the inert gas bottle 1 increases with the ambient temperature, the pressure also increases. When the temperature of the carbon dioxide in the bottle is higher than 505°C and the pressure reaches 17.64MPa~21.56MPa, the safety film ruptures, and the carbon dioxide is led to the venting port 15 through the conduit, and the gas cylinder deflates itself.

[0047] The gas release lock mechanism 2 and the filter 4 are connected through a pipeline, and a pipeline heater 3 is arranged on the pipeline. The pipeline heater 3 is a stainless steel conduit wrapped with glass lacquer cloth and wound with a resistance wire, and the resistance wire is wrapped with organic glass lacquer cloth and a heat insulation pad. When the inert gas is used, the pipeline heater 3 is used to energize its resistance wire to achieve the purpose of heating the stainless steel conduit to prevent the carbon dioxide from absorbing heat when it is released (liquid becomes gas) and causing the pipeline between the gas release lock mechanism 2) and the filter 4 to be frozen and blocked.

[0048] A metal filter is installed inside the filter 4 to filter out mechanical impurities in the carbon dioxide and prevent the impurities from entering the fuel tank.

[0049] The function of the pressure reducer 5 is to reduce the pressure of the inert gas from 15-16MPa to 0.3MPa before spraying it into the fuel tank. When the outlet pressure increases to 0.5MPa-0.6MPa, the pressure relief device (which can be a safety valve) on the pressure reducer 5 opens to prevent the gas entering the fuel tank from overpressure and damaging the fuel tank.

[0050] The pressure reducer heating box 6 is used for the installation, fixing and heating of the pressure reducer 5 to prevent the pressure reducer 5 from malfunctioning due to low temperature or from ice forming inside to block the inflation passage.

[0051] The current limiting heater 7 is used to limit the amount of gas charged into the fuel tank, so as to extend the charging time of the inerting system and keep the fuel tank in an inerting state for a long time. The diameter of the current limiting nozzle of the current limiting heater 7 is an adjustable component, which is 1 to 2 mm and can be adjusted according to different flow requirements to control the carbon dioxide flow rate at 5 kg to 12 kg / h. At the same time, the current limiting heater 7 is provided with a resistance wire for heating, which can prevent the current limiting nozzle from being blocked due to ice when releasing the inerting gas.

[0052] The small flow solenoid valve 8 is used to cut off and connect the passage for filling the oil tank with a small flow of inert gas. The small flow solenoid valve 8 consists of a DC electromagnet and a direct-acting valve. It adopts 28V electrical control. The electromagnet is equipped with a micro switch connected to the on-board indicator light. When the electromagnet is energized, the on-board indicator light connected to the micro switch lights up, and the direct-acting valve is pulled up to connect the gas path. When the power is off, the direct-acting valve returns to the normally closed state.

[0053] One of the two sedimentation tanks 10 is connected to the small flow electromagnetic valve 8, and the other sedimentation tank 10 is connected to the large flow electromagnetic valve 9; the sedimentation tank 10 is an aluminum alloy container with a volume of 1L, installed at a lower position of the pipeline, and is used to collect the residual oil reversely leaked in the pipeline of the inert gas system. One sedimentation tank 10 is used for the small flow inflation pipeline, and the other is used for the large flow inflation pipeline.

[0054] The sedimentation tank 10 is provided with an oil drain switch 11. After the flight, the oil drain switch 11 is opened to drain the fuel in the sedimentation tank 10.

[0055] The one-way valve 12 is used to prevent the oil in the oil tank from flowing back into the inert gas system pipeline.

[0056] A float valve 13 is installed at the outlet of the gas pipeline of each fuel tank. The float valve 13 is opened and closed by the control of the fuel level in the fuel tank. When the liquid level in a certain fuel tank is high, the float valve 13 floats up under the action of buoyancy to prevent the liquid from entering the inert gas system pipeline due to the influence of liquid surface shaking, and at the same time cuts off the inert gas charging passage of the fuel tank. The inert gas is first used to inflate the remaining fuel tanks with less oil, which can play a role in regulating the charging amount of each fuel tank.

[0057] (II) Explosion-proof when the aircraft is in the descending state:

[0058] When the aircraft makes an emergency descent, the atmospheric pressure of the external environment increases sharply, and the pressure difference between the inside and outside of the fuel tank increases accordingly. In order to balance the pressure difference between the inside and outside of the fuel tank and ensure the safety of the fuel tank structure and fuel supply, the on-board power supply is connected to the large-flow solenoid valve 9. After passing through the pressure reducer 5, the gas does not pass through the current limiting heater 7 and the small-flow solenoid valve 8, but directly enters the aircraft fuel tank from the large-flow solenoid valve 9, the sedimentation tank 10, the one-way valve 12, and the nozzle 14. The inert gas is filled into each fuel tank at a large flow rate for a short time, and the carbon dioxide flow rate is 15kg~18kg / h.

[0059] The large flow electromagnetic valve 9 is used to cut off and connect the passage for filling the oil tank with a large flow of inert gas, and its working principle is the same as that of the small flow electromagnetic valve 8.

[0060] (III) Auxiliary fire extinguishing:

[0061] When a fire occurs on the aircraft and the fire extinguishing agent is released, the onboard power supply provides a 28V electrical signal to control the fire extinguishing passage of the gas release lock mechanism 2 to open, and the gas in the inert gas bottle 1 enters the aircraft fire extinguishing pipeline through the three-way one-way valve 16. By releasing a large amount of inert gas to the fire extinguishing pipeline and the fire extinguishing system in a short time, the fire extinguishing function can be realized again.

[0062] The above only expresses the implementation mode of the present invention, and its description is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. In addition, the parts not detailed in the present invention are all conventional technologies.

Claims

1. An aircraft fuel tank explosion-proof system, characterized in that: include: An inert gas bottle (1), a filter (4), a pressure reducer (5), a pressure reducer heating box (6), a small flow electromagnetic valve (8), a large flow electromagnetic valve (9), a sedimentation tank (10), a check valve (12), a float valve (13), a nozzle (14), a venting port (15), and a three-way check valve (16). The inert gas bottle (1) stores inert gas. A gas release lock mechanism (2) is installed at the bottle mouth of the inert gas bottle (1). The gas release lock mechanism (2) is provided with three outlets, which are respectively connected to the filter (4), the venting port (15), and the three-way check valve (16) through pipelines. A pipeline heater (3) is provided on the pipeline between the gas release lock mechanism (2) and the filter (4). The filter (4) The pressure reducer (5) is connected to the inlet of the pressure reducer (5) through a pipeline, and the pressure reducer (5) is installed inside the pressure reducer heating box (6); the pressure reducer (5) is provided with two outlets, one of which is connected to the inlet of a small flow electromagnetic valve (8) through a conduit via a current limiting heater (7), and the other is connected to the inlet of a large flow electromagnetic valve (9) through a conduit; the outlet of the small flow electromagnetic valve (8) is connected to a sedimentation tank (10), a one-way valve (12), and a nozzle (14) through a pipeline, and the outlet of the large flow electromagnetic valve (9) is connected to another sedimentation tank (10), a one-way valve (12), and a float valve (13) through a pipeline; an oil drain switch (11) is installed at the bottom of each sedimentation tank (10), and the outlet of the three-way one-way valve (16) is connected to the aircraft fire extinguishing system.

2. The aircraft fuel tank explosion-proof system according to claim 1, characterized in that: The gas release lock mechanism (2) is electrically connected to a 28V power supply on board, and the opening or closing of the gas release lock mechanism (2) is controlled by a 28V electrical signal on board.

3. The aircraft fuel tank explosion-proof system according to claim 1, characterized in that: The gas release lock mechanism (2) is provided with a safety film. As the ambient temperature of the inert gas in the inert gas bottle (1) increases, the pressure also increases accordingly. When the temperature of the inert gas in the inert gas bottle (1) is higher than a preset value and the pressure reaches a preset pressure, the safety film ruptures and the inert gas is guided to the gas release port (15) through a conduit.

4. The aircraft fuel tank explosion-proof system according to claim 1, characterized in that: The pipeline heater (3) comprises: Stainless steel conduit, Glass varnished cloth wrapped around stainless steel conduit; Resistance wire wrapped around glass varnished cloth; Plexiglas varnished cloth and thermal insulation pad wrapped around the resistance wire.

5. The aircraft fuel tank explosion-proof system according to claim 1, characterized in that: A metal filter screen is installed inside the filter (4) for filtering mechanical impurities in the inert gas.

6. The aircraft fuel tank explosion-proof system according to claim 1, characterized in that: The current limiting heater (7) is provided with a resistance wire for heating the pipeline.

7. The aircraft fuel tank explosion protection system according to claim 1, characterized in that: The small flow electromagnetic valve (8) is composed of a DC electromagnet and a direct-acting valve. The DC electromagnet is provided with a micro switch, which is connected to an indicator light on the machine. When the DC electromagnet is powered on, the direct-acting valve is pulled up to connect the air path. When the DC electromagnet is powered off, the direct-acting valve returns to a normally closed state.

8. The aircraft fuel tank explosion protection system according to claim 1, characterized in that: The number of inert gas bottles (1) is determined according to the volume of the aircraft fuel tank or the flight time.

9. The aircraft fuel tank explosion protection system according to claim 1, characterized in that: When filling the inert gas, every two gas cylinders are controlled and released simultaneously as a group. After one group of gas cylinders is released, the next group is opened.

10. An aircraft, characterized in that: The invention comprises the aircraft fuel tank explosion-proof system according to any one of claims 1 to 9.

Images