Fire-resistant protection device for a sediment drain valve of an aircraft fuel tank and aircraft

Abstract

The application relates to a fireproof protection device for an aircraft fuel tank sediment drain valve and an aircraft. The fireproof protection device for the aircraft fuel tank sediment drain valve comprises an outer fixing cover, an elastic piece, an inner sealing cover and a high-temperature-resistant sealing ring; wherein the outer fixing cover is installed to the fuel tank, the inner sealing cover comprises a lower flange, the high-temperature-resistant sealing ring is installed between the lower flange of the inner sealing cover and a lower wall plate of the fuel tank, the elastic piece is installed between the inner top surface of the outer fixing cover and the lower flange of the inner sealing cover, the outer fixing cover comprises a plurality of flow-through channels located on the side surface of the outer fixing cover, the inner sealing cover is designed as a full sealing type and is used for covering the sediment drain valve. According to the above technical scheme, the application can achieve the following beneficial technical effects: the fireproof protection device can realize the fireproof performance while not affecting the original maintenance and discharge functions of the sediment drain valve.

Description

Technical Field

[0001] This invention relates to a fire-resistant protective device for an aircraft fuel tank settling valve and an aircraft including the device, and relates to the field of aircraft fuel fire prevention technology. Background Technology

[0002] Civil aircraft fuel tanks are equipped with drain valves on the lower bulkhead to drain accumulated water and fuel when the aircraft is parked on the ground. To ensure complete emptying, the drain valve needs to be installed at the lowest point of the tank. For three-tank aircraft, the lowest point of the outer wing fuel tank is typically located behind the engine. According to CCAR / 14CFR 25.867, the fuselage surface within one nacelle diameter (also known as the 2D area) aft of the engine nacelle centerline must be fire-resistant to prevent fuel leakage outside the aircraft in the event of an engine fire, which could exacerbate the accident. Due to its location at the lowest point of the tank, the drain valve of the outer wing fuel tank is easily placed within the 2D area when directly installed. Therefore, the drain valve of the outer wing fuel tank must meet the fire resistance requirement of CCAR / 14CFR 25.867, which requires it to withstand a flame of 1100°C for 5 minutes without fuel leakage.

[0003] Because the settling valve is installed on the lower wall panel, the lower surfaces of the non-metallic flange and valve stem are exposed on the wing surface. However, the heat distortion temperature of aerospace non-metallic materials is usually much lower than 1100°C. Moreover, there are sealing positions on the exposed flange and valve stem, and these sealing positions are close to the outside. If the settling valve is continuously exposed to fire, these two sealing positions are prone to failure due to material heat deformation, resulting in fuel leakage.

[0004] In current engineering practice, to ensure that non-metallic sedimentation valves meet fire resistance requirements, the following two methods are commonly used:

[0005] One approach is to not change the product material, but to thicken the flange of the settling valve, utilizing the flame-retardant properties of the aerospace non-metallic material itself to protect the two sealing points from external flames and prevent fuel leakage within the required fire resistance time.

[0006] Another approach involves replacing part of the valve body with metal and moving the sealing position upwards to avoid external flames. The valve body flange and lower valve stem are exposed to the atmosphere and are therefore still made of non-metallic materials, ensuring the equipment's lightning safety. The secondary lifting valve and the upper part of the valve body are located internally and are made of metal, directly contacting the non-metallic parts. The excellent thermal conductivity of the metal material is used to dissipate the heat from the non-metallic materials in a timely manner. At the same time, the valve's sealing position is also moved into the oil tank, away from external flames, preventing direct exposure of the sealing position to fire and thus avoiding fuel leakage.

[0007] The shortcomings of the existing technology are as follows:

[0008] The first type of settling valve originally had a maintenance function. When the valve stem moved downwards, the sealing ring at the bottom of the valve stem could be exposed, while the sealing ring at the top of the valve stem remained sealed. When the settling valve leaked oil, this maintenance function allowed for inspection or replacement of the valve stem sealing ring without emptying the oil tank. However, after the flange was thickened, the equipment maintenance function was lost. When the settling valve leaked oil, the entire settling valve had to be repaired or replaced by emptying the oil tank, increasing maintenance time and costs.

[0009] In the second method, the upward shift of the sealing position raises the inlet position of the sediment discharge valve, which is not conducive to the complete discharge of water and fuel accumulated at the bottom of the fuel tank. Furthermore, the secondary lifting causes the outlet of the discharge channel to narrow, reducing the discharge rate and making the channel prone to blockage, thus affecting the equipment's discharge capacity. In addition, the reliable combination of metals and non-metals increases the technological complexity of the equipment, leading to increased production cycle and costs.

[0010] In addition, the above two methods not only cause the settling valve to undergo varying degrees of functional degradation, but also make the configuration of the settling valve located in the 2D area different from that in other areas. That is, in order to avoid the aforementioned functional degradation as much as possible, each aircraft must have two settling valve configurations at the same time, which reduces the interchangeability of the equipment and makes it difficult for airlines to replace spare parts. Summary of the Invention

[0011] One object of the present invention is to provide a fire-resistant protective device for a sediment discharge valve of an aircraft fuel tank, which can overcome at least some of the defects of the prior art and can achieve fire resistance without affecting the original maintenance and discharge functions of the sediment discharge valve.

[0012] The above-mentioned objective of the present invention is achieved by a fire-resistant protective device for an aircraft fuel tank settling valve, the fire-resistant protective device for an aircraft fuel tank settling valve comprising an outer fixing cover, an elastic element, an inner sealing cover, and a high-temperature resistant sealing ring.

[0013] The outer fixed cover is installed to the oil tank, the inner sealing cover includes a lower flange, the high-temperature resistant sealing ring is installed between the lower flange of the inner sealing cover and the lower wall plate of the oil tank, the elastic element is installed between the inner top surface of the outer fixed cover and the lower flange of the inner sealing cover, the outer fixed cover includes multiple flow channels located on its side, and the inner sealing cover is a fully sealed design used to cover the sedimentation valve.

[0014] According to the above technical solution, the fire-resistant protection device for the sediment discharge valve of the aircraft fuel tank of the present invention can achieve the following beneficial technical effects: it can achieve fire resistance without affecting the original maintenance and discharge functions of the sediment discharge valve.

[0015] Preferably, the outer fixing cover is installed on the lower wall panel of the oil tank or the vertical structure of the oil tank.

[0016] According to the above technical solution, the fire-resistant protective device for the sediment discharge valve of aircraft fuel tank of the present invention can achieve the following beneficial technical effects: it has strong versatility, and its shape and installation method can be changed according to the actual situation of the fuel tank.

[0017] Preferably, the lowest point of the flow channel of the multiple flow channels of the outer fixed cover is lower than the inlet of the flow channel of the sediment discharge valve.

[0018] According to the above technical solution, the fire-resistant protective device for the sediment discharge valve of the aircraft fuel tank of the present invention can achieve the following beneficial technical effects: it does not affect the full discharge of sediment in the fuel tank.

[0019] Preferably, the outer fixing cover and the inner sealing cover are made of a fuel-resistant metal material.

[0020] According to the above technical solution, the fire-resistant protective device for the sediment discharge valve of aircraft fuel tank of the present invention can achieve the following beneficial technical effects: the main body of the device is made of the same kind of fire-resistant metal material, which does not require the combination of metal and non-metal materials, the process is simple, and the manufacturing cycle and manufacturing cost can be shortened.

[0021] Preferably, the outer fixing cover further includes a recess located on its inner top surface, and the inner sealing cover further includes an upper boss configured to be received in the recess.

[0022] According to the above technical solution, the fire-resistant protective device for the sediment discharge valve of the aircraft fuel tank of the present invention can achieve the following beneficial technical effects: the recess and the upper boss can limit the operation of the inner sealing cover.

[0023] Preferably, in conjunction with the three working positions of the settling valve (closed, maintenance, and open), the fire-resistant protective device for the settling valve of the aircraft fuel tank has two working states: a closed state and an open state.

[0024] When the settling valve is in the closed and maintenance positions, the inner sealing cover is tightly sealed to the lower wall of the oil tank under the elastic force of the elastic element, and the fire-resistant protection device is in the closed state at this time.

[0025] When the settling valve is in the open position, the inner sealing cover opens as the valve stem of the settling valve moves upward, and a discharge channel for the liquid in the oil tank is formed between the lower flange of the inner sealing cover and the lower wall plate of the oil tank. At this time, the fire-resistant protection device is in the open state.

[0026] According to the above technical solution, the fire-resistant protective device for the sediment drain valve of an aircraft fuel tank of the present invention can achieve the following beneficial technical effects: when the sediment drain valve fails to seal due to continuous fire, it can still achieve the sealing of the fuel tank at that location, preventing fuel in the fuel tank from leaking outside the aircraft and causing more serious accident consequences; it does not affect the maintenance operation of the sediment drain valve and provides double sealing protection, avoiding fuel leakage from the fuel tank to the outside of the aircraft during maintenance operations, reducing the maintenance time and cost of the sediment drain valve while enhancing the reliability of maintenance; when the sediment drain valve is performing sediment draining operation, the inner sealing cover opens accordingly, without affecting the full discharge of sediment in the fuel tank to the outside of the fuel tank.

[0027] Preferably, the ratio of the inner diameter of the recess of the outer fixing cover to the outer diameter of the inner sealing cover is 0.3 to 0.7:1.

[0028] According to the above technical solution, the fire-resistant protective device for the sediment discharge valve of the aircraft fuel tank of the present invention can achieve the following beneficial technical effects: by using a suitable ratio of the inner diameter of the outer fixing cover recess to the outer diameter of the inner sealing cover, the outer fixing cover and the inner sealing cover can be better limited.

[0029] Preferably, the ratio of the outer diameter of the upper boss of the inner sealing cover to the outer diameter of the inner sealing cover is 0.2 to 0.6:1.

[0030] According to the above technical solution, the fire-resistant protective device for the sediment discharge valve of the aircraft fuel tank of the present invention can achieve the following beneficial technical effects: by using a suitable ratio of the outer diameter of the upper boss of the inner sealing cover to the outer diameter of the inner sealing cover, the outer fixing cover and the inner sealing cover can be better limited.

[0031] The above-mentioned objectives of the present invention are also achieved by an aircraft comprising a fire-resistant protective device for an aircraft fuel tank settling valve as described in any of the above aspects.

[0032] According to the above technical solution, the aircraft of the present invention can achieve the following beneficial technical effects: it can achieve fire resistance without affecting the original maintenance and discharge functions of the sedimentation valve. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of a fire-resistant protective device for an aircraft fuel tank sediment discharge valve according to an embodiment of the present invention.

[0034] Figure 2A This is an installation diagram of a fire-resistant protective device for an aircraft fuel tank settling valve in the closed state, according to an embodiment of the present invention.

[0035] Figure 2B This is an installation diagram of a fire-resistant protective device for an aircraft fuel tank settling valve in the open state, according to an embodiment of the present invention.

[0036] Figure 3A This is a front view of a fire-resistant protective device for an aircraft fuel tank settling valve, according to another embodiment of the present invention.

[0037] Figure 3B This is a side view of a fire-resistant protective device for an aircraft fuel tank settling valve, according to another embodiment of the present invention.

[0038] Figure 3C This is a top view of a fire-resistant protective device for an aircraft fuel tank settling valve, according to another embodiment of the present invention.

[0039] Figure 4 This is an installation diagram of a fire-resistant protective device for an aircraft fuel tank settling valve in the closed state, according to another embodiment of the present invention.

[0040] List of reference numerals

[0041] 1: External fixing cover;

[0042] 2: Elastic components;

[0043] 3: Inner sealing cover;

[0044] 4: High-temperature resistant sealing ring;

[0045] 5: Fastener mounting holes;

[0046] 6: Distribution channels;

[0047] 8: Settling valve;

[0048] 9: Lower wall panel of fuel tank;

[0049] 10: Valve stem;

[0050] 11: Vertical structure of the fuel tank;

[0051] 12: concave part;

[0052] 31: Lower flange;

[0053] 32: Upper boss. Detailed Implementation

[0054] The following describes specific embodiments of the present invention. It should be noted that, in order to provide a concise description, this specification cannot exhaustively describe all features of the actual embodiments. It should be understood that, in the actual implementation of any embodiment, just as in any engineering or design project, various specific decisions are often made to achieve the developer's specific goals and to meet intake-related or commercially relevant constraints, and this can change from one embodiment to another. Furthermore, it is understood that although the efforts made in this development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this invention, some design, manufacturing, or production modifications based on the technical content disclosed herein are merely conventional technical means and should not be construed as insufficient content of this disclosure.

[0055] Unless otherwise defined, the technical or scientific terms used in the claims and description shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in the patent application description and claims of this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. The terms "an" or "a" and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms "comprising" or "including" and similar terms mean that the element or object preceding "comprising" or "including" encompasses the element or object listed following "comprising" or "including" and its equivalents, and do not exclude other elements or objects. The terms "connected" or "linked" and similar terms are not limited to physical or mechanical connections, nor are they limited to direct or indirect connections.

[0056] Figure 1 This is a schematic diagram of the structure of a fire-resistant protective device for an aircraft fuel tank sediment discharge valve according to an embodiment of the present invention. Figure 2A This is an installation diagram of a fire-resistant protective device for an aircraft fuel tank settling valve in the closed state, according to an embodiment of the present invention. Figure 2B This is an installation diagram of a fire-resistant protective device for an aircraft fuel tank settling valve in the open state, according to an embodiment of the present invention. Figure 3A This is a front view of a fire-resistant protective device for an aircraft fuel tank settling valve, according to another embodiment of the present invention. Figure 3B This is a side view of a fire-resistant protective device for an aircraft fuel tank settling valve, according to another embodiment of the present invention. Figure 3C This is a top view of a fire-resistant protective device for an aircraft fuel tank settling valve, according to another embodiment of the present invention. Figure 4This is an installation diagram of a fire-resistant protective device for an aircraft fuel tank settling valve in the closed state, according to another embodiment of the present invention.

[0057] like Figures 1 to 4 As shown, according to some embodiments of the present invention, a fire-resistant protective device for an aircraft fuel tank settling valve includes an outer fixing cover 1, an elastic element 2 (e.g., a spring), an inner sealing cover 3, and a high-temperature resistant sealing ring 4.

[0058] The outer fixed cover 1 is installed to the oil tank, the inner sealing cover 3 includes a lower flange 31, a high-temperature resistant sealing ring 4 is installed between the lower flange 31 of the inner sealing cover 3 and the lower wall plate 9 of the oil tank, the elastic element 2 is installed between the inner top surface of the outer fixed cover 1 and the lower flange 31 of the inner sealing cover 3, the outer fixed cover 1 includes multiple flow channels 6 located on its side, and the inner sealing cover 3 is a fully sealed design used to cover the sedimentation valve 8.

[0059] According to the above technical solution, the fire-resistant protection device for the sediment discharge valve of the aircraft fuel tank of the present invention can achieve the following beneficial technical effects: it can achieve fire resistance without affecting the original maintenance and discharge functions of the sediment discharge valve.

[0060] Specifically, the key to achieving fire resistance for the defrost valve itself is protecting its sealing position from external flames, which inevitably sacrifices some of the equipment's maintainability and venting capabilities. This invention can be directly installed and used on aircraft in conjunction with the defrost valve in the 2D area. Through the design of this invention, fuel leakage to the outside of the aircraft will not occur even when the area is continuously exposed to fire. In other words, the defrost valve itself does not need to have fire resistance capabilities, allowing it to maximize its maintainability and venting capabilities. This invention can solve the contradiction between the fire resistance design, maintenance design, and venting design of the defrost valve in one fell swoop, avoiding a series of problems caused by fire resistance design of the defrost valve in the prior art, such as loss of maintenance position function, narrowing of the venting channel leading to reduced venting flow and easy clogging, and insufficient venting of fuel tank sediment due to raised venting inlet. At the same time, the use of this invention eliminates the need to modify the defrost valve itself and avoids differences in defrost valve configuration between the 2D area and other areas, solving the problem of poor equipment interchangeability caused by the presence of different configurations of defrost valves on the same aircraft.

[0061] This invention achieves fire resistance without affecting the original function of the sediment release valve: This invention can prevent fuel leakage at this location when exposed to external fire, without affecting the maintenance, discharge, or other equipment functions of the sediment release valve, and will not add any extra steps to the sediment release operation of the aircraft fuel tank.

[0062] In some embodiments, such as Figures 1 to 2BAs shown, the outer fixed cover 1 is a fixed component, and its lower flange has multiple fastener mounting holes 5 for connection with the lower wall plate 9 of the fuel tank. The outer fixed cover 1 is a non-sealed design, with multiple flow channels 6 evenly spaced on its side. The flow channels 6 are as close as possible to the lower wall plate 9 of the fuel tank. That is, the lowest point of the flow channels 6 of the outer fixed cover 1 is lower than the flow inlet of the settling valve 8. The outer fixed cover 1 also includes a recess 12 located on its inner top surface, forming a stepped structure that can limit the movement of the elastic element 2 and the inner sealing cover 3. The material of the outer fixed cover 1 is a fuel-resistant metal material that can be in direct contact with aviation fuel for a long time, including but not limited to aluminum alloy. In some embodiments, such as... Figures 1 to 2B As shown, the inner sealing cover 3 is an actuating component. When it moves upward, the fire-resistant protective device is in the open state. After being released, the inner sealing cover 3 can automatically fall down, and the fire-resistant protective device closes. The inner sealing cover 3 is a fully sealed design with no flow channel of its own. A high-temperature resistant sealing ring 4 is installed on the lower surface of its lower flange 31. The high-temperature resistant sealing ring 4 is fixed to the inner sealing cover 3. After the inner sealing cover 3 falls down, it can reliably achieve a seal between the fire-resistant protective device and the lower wall plate 9 of the fuel tank, preventing fuel from leaking out of the engine. The inner sealing cover 3 is limited by the upper boss 32 and the recess 12 of the outer fixed cover 1 (the upper boss 32 is constructed to be accommodated in the recess 12). At the same time, the lower flange 31 of the inner sealing cover 3 can also limit the elastic element 2. The material of the inner sealing cover 3 is a fuel-resistant metal material that can be in direct contact with aviation fuel for a long time, including but not limited to aluminum alloy.

[0063] The main body of the present invention (outer fixing cover 1 and inner sealing cover 3) can be made of common fuel-resistant metal material, and the structure is simple and can be realized by common processing methods, such as machining. This solves the problem of high difficulty in the combination of metal and non-metal in the prior art, reduces the process difficulty, and can also shorten the manufacturing cycle and manufacturing cost.

[0064] This invention is small in size, simple in structure, and has uniform and uncomplicated installation interface requirements. At the same time, its shape does not have to be cylindrical and can be adjusted to other suitable shapes (such as regular hexagon, regular octagon, etc.) to adapt to different types of sediment discharge valves and different oil tank environments.

[0065] In some embodiments, such as Figures 1 to 2B As shown, the elastic element 2 is fixed at both ends by the inner top surface of the outer fixed cover 1 and the lower flange 31 of the inner sealing cover 3, and is always in a compressed state. When the inner sealing cover 3 moves upward, it continues to be compressed. After being released, its elasticity causes the inner sealing cover 3 to fall automatically and seal tightly with the lower wall plate 9 of the oil tank.

[0066] In some embodiments, such as Figures 1 to 2BAs shown, the ratio of the inner diameter of the recess 12 of the outer fixing cover 1 to the outer diameter of the inner sealing cover 3 is 0.3 to 0.7:1. According to the above technical solution, the fire-resistant protective device for the sediment discharge valve of the aircraft fuel tank of the present invention can achieve the following beneficial technical effects: by using a suitable ratio of the inner diameter of the recess of the outer fixing cover to the outer diameter of the inner sealing cover, the outer fixing cover and the inner sealing cover can be better limited.

[0067] In some embodiments, such as Figures 1 to 2B As shown, the ratio of the outer diameter of the upper boss 32 of the inner sealing cover 3 to the outer diameter of the inner sealing cover 3 is 0.2 to 0.6:1. According to the above technical solution, the fire-resistant protective device for the sediment discharge valve of the aircraft fuel tank of the present invention can achieve the following beneficial technical effects: by using a suitable ratio of the outer diameter of the upper boss of the inner sealing cover to the outer diameter of the inner sealing cover, the outer fixing cover and the inner sealing cover can be better limited.

[0068] In some embodiments, such as Figures 1 to 2B As shown, the ratio of the depth of the recess 12 of the outer fixing cover 1 to the height of the main body of the inner sealing cover 3 is 0.05 to 0.1:1. In some embodiments, such as Figures 1 to 2B As shown, the ratio of the height of the upper boss 32 of the inner sealing cover 3 to the height of the main body of the inner sealing cover 3 is 0.05 to 0.1:1.

[0069] When a non-metallic sedimentation valve is installed in a 2D area, the fire resistance requirements of the 2D area can be met by this invention. The installation method of this invention is as follows: Figures 2A to 2B As shown, first, the inner sealing cover 3 covers the settling valve 8, then the elastic element 2 is placed, and finally the outer fixing cover 1 is placed. The outer fixing cover 1 is connected to the lower wall plate 9 of the oil tank through the fastener mounting hole 5. After the outer fixing cover 1 is fixed to the lower wall plate 9 of the oil tank, the elastic element 2 is in a compressed state, and its own elasticity makes the inner sealing cover 3 fit tightly against the lower wall plate 9 of the oil tank, thereby realizing the installation and fixing of the entire fire protection device.

[0070] The outer fixing cover 1 of this invention is a non-acting component, with multiple flow channels 6 evenly distributed on its side. The main function of the outer fixing cover 1 is to install and fix the components and provide flow channels for liquid when the oil tank is drained of sediment. The inner sealing cover 3 is an actuating component, capable of moving up and down in the vertical direction. The inner sealing cover 3 has no flow channels and is a fully sealed design. Its main function is to provide a secondary seal for the oil tank.

[0071] The settling valve 8 has three working positions: closed, maintenance, and open. Under normal conditions, the settling valve 8 is in the closed position; when the settling valve 8 needs to replace the valve stem seal ring inside the equipment, the valve stem 10 is rotated downwards to the maintenance position; when the settling valve 8 needs to perform a settling operation in the oil tank, the valve stem 10 is rotated upwards to the open position.

[0072] With the three working positions of the settling valve 8, the fire-resistant protection device of this invention has two working states: a closed state and an open state. When the settling valve 8 is in the closed or maintenance position, the inner sealing cover 3 is tightly sealed to the lower wall plate 9 of the oil tank under the elastic force of the elastic element 2. Figure 2A As shown, the fire-resistant protective device is in the closed state at this time; when the settling valve is in the open position, the inner sealing cover 3 opens as the valve stem 10 moves upward, and a discharge channel for the liquid in the oil tank is formed between the lower flange 31 of the inner sealing cover 3 and the lower wall plate 9 of the oil tank, as shown. Figure 2B As shown, the fire-resistant protective device is in the open state at this time. At the same time, the flow channel 6, being as close as possible to the lower wall plate 9 of the oil tank, will not affect the full discharge of sediment in the oil tank. When the sediment discharge is completed and the sediment discharge valve 8 is closed, the inner sealing cover 3 will automatically fall down with the downward movement of the valve stem 10, and the fire-resistant protective device can reliably be in the closed state.

[0073] When a fire occurs outside the fuel tank, the double-layer semi-sealed and semi-operated design of this invention ensures that even if the settling valve 8 fails to seal due to continuous exposure to fire, the inner sealing cover 3 can still seal the fuel tank, preventing fuel from leaking out of the engine and causing more serious accident consequences.

[0074] In other embodiments, such as Figures 3A to 4 As shown, the present invention can also adapt to different models of sediment discharge valve arrangement by changing the form of the external fixed cover 1, according to different oil tank environments. Figures 3A to 4 As shown, the flange of the outer fixed cover 1 can also be designed on the side, with fastener mounting holes 5 evenly distributed on the flange. A flow channel 6, as close as possible to the lower wall plate, is still provided on the side. The top design of the outer fixed cover 1 remains unchanged, as do the designs of the inner sealing cover 3 and the elastic element 2. When the location of the settling valve is close to the rib or other vertical structures inside the tank, resulting in no space on the lower wall plate of the tank around the settling valve for fastener holes, the outer fixed cover 1 with its flange designed on the side can be installed and fixed to the vertical structure 11 of the tank. The installation method is as follows: Figure 4 As shown, the installation method of the inner sealing cover 3 and the elastic element 2 remains unchanged. The outer fixed cover 1 is connected to the vertical structure 11 of the oil tank by fasteners. After installation, the elastic element 2 is in a compressed state. Under this design, the present invention can still achieve the following: when the sediment discharge valve 8 is in the closed and maintenance position, the inner sealing cover 3 and the lower wall plate 9 of the oil tank are in the closed state, and the inner sealing cover 3 is in the open state when the sediment discharge valve 8 is in the open position. The inner sealing cover 3 opens with the upward movement of the valve stem 10, providing a flow channel for the liquid discharge in the oil tank. At the same time, when the sediment discharge ends and the sediment discharge valve 8 is closed, the inner sealing cover 3 automatically falls down with the downward movement of the valve stem 10, reliably being in the closed state.

[0075] When a fire occurs outside the fuel tank, the inner sealing cover 3 of this design can still seal the fuel tank, preventing fuel from leaking out of the engine and causing more serious accident consequences.

[0076] According to one embodiment of the present invention, an aircraft includes a fire-resistant protective device for an aircraft fuel tank settling valve as described in any of the above aspects. Based on the above technical solution, the aircraft of the present invention can achieve the following beneficial technical effects: it can achieve fire resistance without affecting the original maintenance and discharge functions of the settling valve.

[0077] The specific embodiments of the present invention have been described above. However, those skilled in the art will understand that the above specific embodiments do not constitute a limitation on the present invention. Those skilled in the art can make various modifications based on the above disclosure without exceeding the scope of the present invention.

Claims

1. A fire-resistant protective device for a sediment discharge valve in an aircraft fuel tank, characterized in that, The fire-resistant protective device for the sediment discharge valve of the aircraft fuel tank includes an outer fixing cover, an elastic element, an inner sealing cover, and a high-temperature resistant sealing ring. The outer fixed cover is installed to the oil tank, the inner sealing cover includes a lower flange, the high-temperature resistant sealing ring is installed between the lower flange of the inner sealing cover and the lower wall plate of the oil tank, the elastic element is installed between the inner top surface of the outer fixed cover and the lower flange of the inner sealing cover, the outer fixed cover includes multiple flow channels located on its side, and the inner sealing cover is a fully sealed design used to cover the sedimentation valve.

2. The fire-resistant protective device for an aircraft fuel tank settling valve as described in claim 1, characterized in that, The external fixing cover is installed on the lower wall panel of the oil tank or the vertical structure of the oil tank.

3. The fire-resistant protective device for an aircraft fuel tank settling valve as described in claim 1, characterized in that, The lowest point of the flow channels of the multiple flow channels of the outer fixed cover is lower than the inlet of the flow channel of the sediment discharge valve.

4. The fire-resistant protective device for an aircraft fuel tank settling valve as described in claim 1, characterized in that, The outer fixing cover and the inner sealing cover are made of fuel-resistant metal material.

5. The fire-resistant protective device for an aircraft fuel tank settling valve as described in claim 1, characterized in that, The outer fixing cover also includes a recess located on its inner top surface, and the inner sealing cover also includes an upper boss configured to be received in the recess.

6. The fire-resistant protective device for an aircraft fuel tank settling valve as described in claim 1, characterized in that, In conjunction with the three working positions of the settling valve (closed, maintenance, and open), the fire-resistant protective device for the settling valve of the aircraft fuel tank has two working states: closed and open. When the settling valve is in the closed and maintenance positions, the inner sealing cover is tightly sealed to the lower wall of the oil tank under the elastic force of the elastic element, and the fire-resistant protection device is in the closed state at this time. When the settling valve is in the open position, the inner sealing cover opens as the valve stem of the settling valve moves upward, and a discharge channel for the liquid in the oil tank is formed between the lower flange of the inner sealing cover and the lower wall plate of the oil tank. At this time, the fire-resistant protection device is in the open state.

7. The fire-resistant protective device for an aircraft fuel tank settling valve as described in claim 5, characterized in that, The ratio of the inner diameter of the recess of the outer fixing cover to the outer diameter of the inner sealing cover is 0.3 to 0.7:

1.

8. The fire-resistant protective device for an aircraft fuel tank settling valve as described in claim 5, characterized in that, The ratio of the outer diameter of the upper boss of the inner sealing cover to the outer diameter of the inner sealing cover is 0.2 to 0.6:

1.

9. An aircraft comprising a fire-resistant protective device for a sediment discharge valve for an aircraft fuel tank as described in any one of claims 1-8.

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