Ventilation port assembly and ventilation oil tank with ventilation port assembly

Abstract

The utility model provides a ventilation oil tank which is used as a buffer area between a main oil tank of an airplane and the outside atmosphere and comprises a first compartment, a second compartment and a middle compartment located between the first compartment and the second compartment. The ventilation oil tank further comprises a ventilation pipeline communicated with the main oil tank and a main one-way valve located between the second compartment and the main oil tank and opened towards the main oil tank. The ventilation oil tank further comprises a drainage channel communicating the first compartment and the second compartment through fluid. A first vent that fluidly communicates the first compartment with the intermediate compartment; a second vent that fluidly communicates the second compartment with the intermediate compartment; the secondary one-way valve is arranged between the second compartment and the middle compartment and is opened towards the second compartment; and the ventilation port assembly is mounted on the lower wall plate of the middle compartment, so that the ventilation oil tank is communicated with the outside atmosphere. The utility model further provides an air vent assembly with the pressure stabilizing flaring, and aims to enable the pressure in the ventilation oil tank to be stable and avoid or reduce the risk of damage to components in a flow channel or overpressure of the oil tank caused by violent or frequent fluctuation of the pressure in the ventilation oil tank.

Description

Technical Field

[0001] The utility model relates to the field of aircraft fuel tank ventilation, and more particularly to a ventilation port assembly with a voltage stabilizing component and a ventilation fuel tank with such a ventilation port assembly. Background Art

[0002] Currently, the fuel tanks of civil aviation passenger aircraft usually include a central fuel tank located in the belly of the aircraft, left and right main fuel tanks respectively located in the wings, and a ventilation fuel tank that balances the internal pressure of the fuel tank by exchanging air with the outside atmosphere. In addition, some passenger aircraft also have trim fuel tanks located in the horizontal tail. There are also some passenger aircraft that may have a central auxiliary fuel tank.

[0003] Generally, the ventilation fuel tank is arranged near the wing tip. According to relevant regulations, its main functions are as follows: 1. Ensure the ventilation of the fuel tank system under various possible operating conditions of the aircraft, so that the pressure inside and outside the fuel tank is balanced, thereby preventing the fuel tank structure from being damaged due to excessive pressure difference inside and outside the fuel tank. 2. Avoid the spillage of a dangerous amount of fuel outside the aircraft. Thus, it can be seen that the ventilation fuel tank is the key to ensuring the normal operation of the aircraft.

[0004] As Figure 1 shown, the current ventilation fuel tank 1 generally includes a ventilation port assembly 2, a pressure relief valve 3, and a check valve 4. The ventilation port assembly 2 generally includes a ventilation port and a flame arrester. The ventilation port is installed on the lower wall plate of the ventilation fuel tank 1, and a flame arrester is connected upstream thereof; the pressure relief valve 3 is installed on the lower wall plate of the ventilation fuel tank 1; the check valve 4 is installed at the bottom of the partition rib plate between the ventilation fuel tank 1 and the main fuel tank. Among them, the ventilation port assembly 2 is the terminal for the fuel tank to exchange air with the outside atmosphere. The pressure characteristics of the ventilation port assembly 2 will be transmitted to the entire aircraft fuel tank. Under normal circumstances, the ventilation port assembly 2 can ensure that gas exchange meets the pressure-bearing requirements of the fuel tank structure. At the same time, the pressure relief valve 3 provides a backup ventilation channel for the ventilation fuel tank 1.

[0005] During actual flight, affected by the coupling of various factors such as the external atmospheric environment and the flow characteristics of the fuel tank ventilation port, the pressure of the ventilation port assembly may fluctuate violently or frequently, increasing the risk of fatigue damage to the components in the flow channel or overpressure of the fuel tank.

[0006] In addition, during flight, the fuel in the main fuel tank may enter the ventilation fuel tank through the fuel tank ventilation system. The ventilation fuel tank can provide a temporary space for accommodating fuel. At an appropriate time, this part of the fuel will flow back to the main fuel tank through the flapper check valve installed at the bottom of the partition rib plate between the ventilation fuel tank and the main fuel tank. However, before that, the design of the ventilation fuel tank should be able to prevent a dangerous amount of fuel from spilling out of the ventilation port to the outside of the aircraft.

[0007] Therefore, through optimized design, the aircraft ventilation fuel tank should have good voltage stabilizing and anti-fuel spillage characteristics on the basis of realizing its basic functions.

[0008] In the vented fuel tank 11 of the prior art as shown in Figure 2 , the pressure relief valve 13 is installed in the compartment near the wing tip inside the vented fuel tank 11, the vent assembly 12 is installed in the compartment near the wing root inside the vented fuel tank 11, and the check valve 14 is installed at the bottom of the partition rib between the vented fuel tank 11 and the main fuel tank. Among them, the vent assembly 12 includes a vent, a flame arrester and a protective cover. The protective cover can prevent fuel from splashing into the interior of the vent assembly 12 and avoid oil spillage caused by splashing. However, the vented fuel tank 11 of this prior art has deficiencies: 1. The vent assembly 12 is arranged at a position near the wing root in the vented fuel tank 11, making the volume of the vented fuel tank 11 small and failing to make full use of the space of the vented fuel tank 11; 2. Although a protective cover for preventing fuel splashing is designed above its flame arrester, it cannot prevent fuel from overflowing to the outside of the aircraft through the passage between the protective cover and the flame arrester when there is relatively too much fuel in the vented fuel tank 11; 3. The height of the flame arrester itself still limits the fuel holding capacity of the vented fuel tank 11 and increases the possibility of oil spillage from the vent; 4. There are no measures in the vented fuel tank 11 to eliminate or attenuate pressure fluctuations.

[0009] In the vented fuel tank 21 of the prior art as shown in Figure 3 , the installation positions of the vent assembly 22 and the pressure relief valve 23 of the vented fuel tank 21 are the same as the previous method. The difference is that its vent assembly 22 is not a vertical structure but an "S" shape, which consists of a vent, a flame arrester and a section of vent pipe. Among them, the flame arrester is horizontally installed, and a section of vent pipe extending to the middle compartment of the vented fuel tank 21 is horizontally connected downstream of the flame arrester. The height of the inlet of the vent assembly 22 can be increased to a certain extent by means of the upward angle of the wing, thereby increasing the capacity of the vented fuel tank 21 to reduce fuel spillage. In addition, another design feature of this vented fuel tank is that an ejector pump suction port 24 is arranged on the partition rib between the vented fuel tank 21 and the main fuel tank, and the ejector pump in the main fuel tank can be used to pump the fuel in the vented fuel tank 21 back to the main fuel tank to reduce fuel spillage. However, the vented fuel tank 21 of this prior art also has deficiencies: 1. The "S"-shaped vent assembly 22 increases the flow resistance on the one hand, and on the other hand, the horizontally arranged flame arrester in the "S"-shaped flow channel increases the risk of internal blockage, and the flame arrester cannot be directly visually inspected, with low reliability and great operation difficulty. 2. The ejector pump provided to suck the fuel in the vented fuel tank 21 back to the main fuel tank causes the aircraft to gain weight, and when there is more fuel in the vented fuel tank 21, even if the ejector pump and the check valve return the fuel together, the fuel spillage cannot be immediately eliminated. 3. There are no measures in the vented fuel tank 21 to eliminate or attenuate pressure fluctuations.

[0010] In the vented fuel tank as shown in Figure 4In the vented fuel tank 31 of the prior art shown, the one-way valve 34 of the vented fuel tank 31 is located at the bottom of the partition rib between the vented fuel tank 31 and the main structure, while its pressure relief valve 33 and vent assembly 32 are centrally installed on the cover of the intermediate compartment arranged in the vented fuel tank 31. It is constructed such that when the fuel sloshes in the vented fuel tank 31, the inlet of the vent assembly 32 located in the middle position can be at the highest position as much as possible. In addition, while the vent assembly 32 is designed to be a vertical structure, it also includes a section of vent interface installed above the flame arrester 32a, further increasing the volume of the vented fuel tank 31. However, the vented fuel tank 31 of this prior art has deficiencies: 1. The height of the vent interface added in the vent assembly 32 is limited. Even if the vent assembly 32 is installed in the intermediate compartment, there is still some space in the vented fuel tank 31 that cannot be utilized; 2. There are no measures in the vented fuel tank 31 to eliminate or attenuate pressure fluctuations.

[0011] In summary, the current vented fuel tank has the following deficiencies: 1. There are no measures in the vented fuel tank to eliminate or attenuate pressure fluctuations, and there is a risk of damage to components in the flow path or overpressure of the fuel tank when the pressure of the vent assembly fluctuates violently or frequently; 2. The volume of the vented fuel tank is not fully utilized to accommodate fuel; 3. There is a risk of a dangerous amount of fuel spilling outside the aircraft before the fuel in the vented fuel tank flows back to the main fuel tank.

[0012] Therefore, an improved vent assembly and an improved vented fuel tank with such a vent assembly are needed, which can solve at least one of the above deficiencies. Summary of the Utility Model

[0013] To solve the problems of the above prior art, the present utility model proposes a vented fuel tank with a vent assembly. The vented fuel tank is constructed with a drainage passage and an internal vent part, which can achieve at least one of the following purposes: fully utilize the volume of the vented fuel tank to accommodate fuel; avoid a dangerous amount of fuel spilling outside the aircraft before the fuel in the vented fuel tank flows back to the main fuel tank; make the pressure in the vented fuel tank stable and avoid or reduce the risk of damage to components in the flow path or overpressure of the fuel tank caused by violent or frequent pressure fluctuations in the vented fuel tank. The present utility model also proposes a vent assembly with a pressure stabilizing flare, the purpose of which is to make the pressure in the vented fuel tank stable and avoid or reduce the risk of damage to components in the flow path or overpressure of the fuel tank caused by violent or frequent pressure fluctuations in the vented fuel tank.

[0014] Accordingly, in a first aspect, the present utility model provides a vented fuel tank which serves as a buffer area between the main fuel tank of an aircraft and the outside atmosphere. The vented fuel tank includes a first compartment near the wing tip of the aircraft, a second compartment near the wing root of the aircraft, and an intermediate compartment located between the first compartment and the second compartment. The vented fuel tank further includes a ventilation pipeline communicating with the main fuel tank and a main one-way valve located between the second compartment and the main fuel tank and opening towards the main fuel tank. The vented fuel tank further includes: a drainage passage fluidly connecting the first compartment and the second compartment; a first ventilation part fluidly connecting the first compartment and the intermediate compartment; a second ventilation part fluidly connecting the second compartment and the intermediate compartment; a secondary one-way valve arranged between the second compartment and the intermediate compartment and opening towards the second compartment; and a vent assembly which is installed on the lower wall panel of the intermediate compartment such that the vented fuel tank communicates with the outside atmosphere.

[0015] According to the above technical solution, the vented fuel tank of the present utility model can achieve the following beneficial effects: make full use of the volume of the vented fuel tank to accommodate fuel, avoid the spillage of a dangerous amount of fuel outside the aircraft before the fuel in the vented fuel tank flows back to the main fuel tank, and enable the vented fuel tank to communicate with the outside atmosphere through the vent assembly to adjust the pressure inside the fuel tank.

[0016] In a preferred embodiment of the present utility model, the vent assembly includes a vent hole, a flame arrester installed on the vent, and a pressure stabilizing flare installed on the flame arrester. The pressure stabilizing flare communicates with the flame arrester, and a ventilation opening is provided on the side wall of the pressure stabilizing flare.

[0017] According to the above technical solution, the vented fuel tank of the present utility model can achieve the following beneficial effects: through the vent assembly with a pressure stabilizing flare, the pressure inside the vented fuel tank can be made stable, avoiding or reducing the risk of damage to components in the flow channel or overpressure of the fuel tank caused by violent or frequent fluctuations in the pressure inside the vented fuel tank.

[0018] In a preferred embodiment of the present utility model, the drainage passage is arranged in or on the lower wall panel of the intermediate compartment.

[0019] According to the above technical solution, the vented fuel tank of the present utility model can achieve the following beneficial effects: make full use of the volume of the vented fuel tank to accommodate fuel, avoid the spillage of a dangerous amount of fuel outside the aircraft before the fuel in the vented fuel tank flows back to the main fuel tank.

[0020] In a preferred embodiment of the present utility model, the drainage passage includes a first opening leading to the first compartment and a second opening leading to the second compartment. Among them, the first opening is located at the bottom of the first partition rib between the first compartment and the intermediate compartment, and / or the second opening is located at the bottom of the second partition rib between the second compartment and the intermediate compartment.

[0021] According to the above technical solution, the ventilation fuel tank of the present utility model can achieve the following beneficial effects: make full use of the volume of the ventilation fuel tank to accommodate fuel, and avoid the overflow of a dangerous amount of fuel outside the aircraft before the fuel in the ventilation fuel tank flows back to the main fuel tank.

[0022] In an embodiment of the present utility model, the drainage passage is composed of stringers or pipelines.

[0023] According to the above technical solution, the ventilation fuel tank of the present utility model can achieve the following beneficial effects: make full use of the volume of the ventilation fuel tank to accommodate fuel, and avoid the overflow of a dangerous amount of fuel outside the aircraft before the fuel in the ventilation fuel tank flows back to the main fuel tank.

[0024] In a preferred embodiment of the present utility model, the first ventilation part is located at the top of the first partition rib between the first compartment and the middle compartment, and / or the second ventilation part is located at the top of the second partition rib between the second compartment and the middle compartment.

[0025] According to the above technical solution, the ventilation fuel tank of the present utility model can achieve the following beneficial effects: make full use of the volume of the ventilation fuel tank to accommodate fuel, and avoid the overflow of a dangerous amount of fuel outside the aircraft before the fuel in the ventilation fuel tank flows back to the main fuel tank.

[0026] In an embodiment of the present utility model, the ventilation fuel tank further includes an auxiliary drainage passage arranged at the top of the first compartment. One end of the auxiliary drainage passage is connected to the first ventilation part, and the other end is close to the wing tip of the aircraft.

[0027] According to the above technical solution, the ventilation fuel tank of the present utility model can achieve the following beneficial effects: make full use of the volume of the ventilation fuel tank to accommodate fuel, and avoid the overflow of a dangerous amount of fuel outside the aircraft before the fuel in the ventilation fuel tank flows back to the main fuel tank.

[0028] In a preferred embodiment of the present utility model, the second ventilation part is a float valve, and the float valve is configured to close when the liquid level in the second compartment reaches a preset position.

[0029] According to the above technical solution, the ventilation fuel tank of the present utility model can achieve the following beneficial effects: make full use of the volume of the ventilation fuel tank to accommodate fuel, and avoid the overflow of a dangerous amount of fuel outside the aircraft before the fuel in the ventilation fuel tank flows back to the main fuel tank.

[0030] In a preferred embodiment of the present utility model, the material of the drainage passage is at least one of aluminum alloy and electrostatic conductive composite materials.

[0031] According to the above technical solution, the ventilation fuel tank of the present utility model can achieve the following beneficial effects: avoid the occurrence of ignition sources in the fuel tank and extend the service life of the drainage passage in the ventilation fuel tank.

[0032] In a second aspect, the present utility model proposes a ventilation port assembly for a ventilation fuel tank of an aircraft. The ventilation port assembly includes a ventilation port and a flame arrester installed on the ventilation port. The ventilation port assembly further includes a pressure stabilizing flare installed on the flame arrester, the pressure stabilizing flare is communicated with the flame arrester, and a ventilation opening is provided on the side wall of the pressure stabilizing flare.

[0033] According to the above technical solution, the ventilation port assembly of the present utility model can achieve the following beneficial effects: Through the ventilation port assembly with a pressure stabilizing flare, the pressure in the ventilation fuel tank can be made stable, avoiding or reducing the risk of component damage in the flow channel or fuel tank overpressure caused by violent or frequent fluctuations in the pressure in the ventilation fuel tank.

[0034] In a preferred embodiment of the present utility model, the pressure stabilizing flare includes a first end and a second end opposite to the first end. The first end is connected to the flame arrester, and the second end is a closed end. The pressure stabilizing flare is configured to gradually expand from the first end towards the second end.

[0035] According to the above technical solution, the ventilation port assembly of the present utility model can achieve the following beneficial effects: It can effectively make the pressure in the ventilation fuel tank stable, avoiding or reducing the risk of component damage in the flow channel or fuel tank overpressure caused by violent or frequent fluctuations in the pressure in the ventilation fuel tank.

[0036] In a preferred embodiment of the present utility model, the ventilation opening is positioned near the second end.

[0037] According to the above technical solution, the ventilation port assembly of the present utility model can achieve the following beneficial effects: Increasing the fuel storage capacity of the intermediate compartment, and avoiding the spillage of a dangerous amount of fuel outside the aircraft before the fuel in the ventilation fuel tank flows back to the main fuel tank.

[0038] In a preferred embodiment of the present utility model, the material of the pressure stabilizing flare is at least one of aluminum alloy and electrostatic conductive composite material.

[0039] According to the above technical solution, the ventilation port assembly of the present utility model can achieve the following beneficial effects: Avoiding the occurrence of ignition sources in the fuel tank and extending the service life of the pressure stabilizing flare in the ventilation fuel tank.

[0040] It should be understood that the above utility model content is provided to introduce in a simplified form a selection of concepts that will be further described in the detailed description. This does not mean determining the key or essential features of the claimed subject matter, and the scope of the claimed subject matter is uniquely defined by the appended claims. In addition, the claimed subject matter is not limited to embodiments that solve any of the above or any disadvantages pointed out in any part of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The further features, exemplary embodiments and advantages of the present utility model will be explained in more detail with reference to the accompanying drawings. It can be understood that this embodiment cannot exhaust the entire scope of the present utility model. It will be further understood that some or all of the features described below can also be combined in other ways, where:

[0042] Figure 1 is a schematic diagram of a breather fuel tank of the prior art;

[0043] Figure 2 is a schematic diagram of a typical design of a breather fuel tank of the prior art;

[0044] Figure 3 is a schematic diagram of another typical design of a breather fuel tank of the prior art;

[0045] Figure 4 is a schematic diagram of yet another typical design of a breather fuel tank of the prior art;

[0046] Figure 5 is a schematic diagram of a breather fuel tank according to the first embodiment of the present utility model;

[0047] Figure 6 is a side view schematic diagram of a breather port assembly according to the present utility model;

[0048] Figure 7a is a schematic diagram of the breather fuel tank according to the first embodiment of the present utility model when there is no fuel;

[0049] Figures 7b - 7d is a schematic diagram of the fuel flow in the breather fuel tank according to the first embodiment of the present utility model;

[0050] Figure 8 is a schematic diagram of the fuel flow in the breather fuel tank according to the second embodiment of the present utility model; and

[0051] Figures 9a - 9c is a schematic diagram of the fuel flow in the breather fuel tank according to the third embodiment of the present utility model.

[0052] List of reference numerals

[0053] 1 breather fuel tank;

[0054] 2 breather port assembly;

[0055] 3 pressure relief valve;

[0056] 4 check valve;

[0057] 11 breather fuel tank;

[0058] 12 breather port assembly;

[0059] 13 Pressure relief valve;

[0060] 14 Check valve;

[0061] 21 Ventilated fuel tank;

[0062] 22 Vent port assembly;

[0063] 23 Pressure relief valve;

[0064] 24 Ejector pump suction port;

[0065] 31 Ventilated fuel tank;

[0066] 32 Vent port assembly;

[0067] 32a Flame arrester;

[0068] 33 Pressure relief valve;

[0069] 34 Check valve;

[0070] 100, 100', 100” Ventilated fuel tank;

[0071] 101 First compartment;

[0072] 102 Second compartment;

[0073] 103 Intermediate compartment;

[0074] 104 Drainage passage;

[0075] 104a First opening;

[0076] 104b Second opening;

[0077] 105 First ventilation part;

[0078] 106 Second ventilation part, float valve;

[0079] 107 Secondary check valve;

[0080] 108 Vent port assembly;

[0081] 108a Flame arrester;

[0082] 108b Pressure stabilizing flared opening;

[0083] 108c Ventilation opening;

[0084] 108d Fuel tank vent;

[0085] 109 Main check valve;

[0086] 110 Vent pipe;

[0087] 111 First partition rib

[0088] 112 Second partition rib

[0089] 115 Auxiliary drainage passage

[0090] 115a Auxiliary drainage passage opening

[0091] 120 Vent pipe Detailed implementation mode

[0092] The present utility model will be described more comprehensively below with reference to the accompanying drawings, in which exemplary embodiments of the present utility model are illustrated. Obviously, all features disclosed in this specification, or all steps in the disclosed methods or processes, except for mutually exclusive features and / or steps, can be combined in any way. Any feature disclosed in this specification, unless specifically stated, can be replaced by other equivalent or similar-purpose alternative features, that is, unless specifically described, each feature is only an example in a series of equivalent or similar features. The technical solutions of the present utility model will be described in many aspects below with reference to the drawings and embodiments.

[0093] In this article, the term "lateral direction" refers to a direction parallel to the direction from the wing root of the aircraft to the wing tip, and the "vertical direction" refers to a direction perpendicular to the lateral direction.

[0094] In this article, terms such as "inner side", "outer side", "inward", "outward", "proximal", "distal", "top", "bottom", etc. are only used to illustrate the relative positions of the elements. For example, "proximal" means relatively close to the wing root of the aircraft, and "distal" means relatively close to the wing tip. For example, "top" means relatively far from the ground, and "bottom" means relatively close to the ground.

[0095] In this article, serial numbers such as "first" and "second" do not represent order (for example, do not imply a sequential relationship, unless clearly stated) or priority or importance. The above serial numbers are only used to indicate that they are different and independent devices, elements or steps.

[0096] Figure 1 is a schematic diagram of the vented fuel tank 1 of the prior art, and Figures 2 - 4 is a schematic diagram of three typical designs of the vented fuel tanks 11, 21, and 31 of the prior art. For the Figures 1 to 4 description, reference can be made to the background art above.

[0097] Figure 5 is a schematic diagram of the vented fuel tank 100 according to the first embodiment of the present utility model. As Figure 5The illustrated vented fuel tank 100 can be used as a buffer area between the main fuel tank of an aircraft and the outside atmosphere. The vented fuel tank 100 includes a first compartment 101, a second compartment 102, and an intermediate compartment 103. The first compartment 101 is close to the wing tip of the aircraft while the second compartment 102 is close to the wing root of the aircraft. The intermediate compartment 103 is located between the first compartment 101 and the second compartment 102. In other words, the first compartment 101, the intermediate compartment 103, and the second compartment 102 are arranged in sequence in the lateral direction from the wing tip to the wing root of the aircraft. The first compartment 101 is separated from the intermediate compartment 103 by a first dividing rib plate 111, while the second compartment 102 is separated from the intermediate compartment 103 by a second dividing rib plate 112. The first compartment 101, the intermediate compartment 103, and the second compartment 102 are in communication with each other in pairs, which will be described in more detail below.

[0098] The vented fuel tank 100 further includes a main one-way valve 109, which is located between the second compartment 102 and the main fuel tank and is configured to open towards the main fuel tank, that is, configured to be in one-way communication with the main fuel tank. Specifically, the main one-way valve 109 can allow the fuel in the vented fuel tank 100 to flow back into the main fuel tank unidirectionally. Preferably, the main one-way valve 109 is arranged close to the bottom of the dividing rib plate between the second compartment 102 and the main fuel tank. More preferably, the main one-way valve 109 is arranged at the lowest point of the dividing rib plate between the second compartment 102 and the main fuel tank.

[0099] The vented fuel tank 100 further includes a vent pipe 110 that is in fluid communication with the main fuel tank. The vent pipe 110 fluidly connects the vented fuel tank 100 and the main fuel tank, so that the pressure inside the main fuel tank can be adjusted through the vented fuel tank 100. The fuel in the main fuel tank can enter the vented fuel tank 100 via the vent pipe 110. In a preferred embodiment, the vent pipe 110 is configured to open into the second compartment 102 of the vented fuel tank 100 close to the wing root of the aircraft. In an alternative embodiment, the vented fuel tank 100 may further include a vent pipe 120 (as Figures 9a - 9c shown) configured to open into the first compartment 101 of the vented fuel tank 100 close to the wing tip of the aircraft.

[0100] The vented fuel tank 100 further includes a drainage passage 104 configured to fluidly connect the first compartment 101 and the second compartment 102. The fuel in the vented fuel tank 100 can flow between the first compartment 101 and the second compartment 102 through the drainage passage 104 to make full use of the space inside the vented fuel tank 100 to accommodate fuel.

[0101] Preferably, the drainage passage 104 is a stringer or a pipeline or other drainage structure arranged on the lower wall panel of the middle compartment 103, that is, the drainage passage 104 is arranged against the lower wall panel of the middle compartment 103. The material of the drainage passage 104 is at least one of materials such as aluminum alloy and electrostatic conductive composite materials that can be in direct contact with aviation fuel for a long time, so as to avoid ignition sources in the vented fuel tank 100 and extend the service life of the drainage passage 104 in the vented fuel tank 100. The drainage passage 104 includes a first opening 104a that opens to the first compartment 101 and a second opening 104b that opens to the second compartment 102. Preferably, the first opening 104a is located at the bottom of the first partition rib 111 between the first compartment 101 and the middle compartment 103, and / or the second opening 104b is located at the bottom of the second partition rib 112 between the second compartment 102 and the middle compartment 103.

[0102] Alternatively, the drainage passage 104 can also be a stringer or a pipeline or other drainage structure arranged in the lower wall panel of the middle compartment 103, but this solution is less preferred because arranging the drainage passage 104 in the lower wall panel may affect the overall structural strength of the lower wall panel of the vented fuel tank 100, resulting in the need for additional reinforcement measures, such as the need to thicken the lower wall panel additionally or to provide additional reinforcement structures.

[0103] In particular, the size of the drainage passage 104 can be designed according to the actual fuel flow rate requirements. More particularly, the vented fuel tank 100 can include more than one drainage passage 104. And, in the case where the vented fuel tank 100 includes more than one drainage passage 104, the drainage passages 104 can be arranged in combination using the above different arrangement schemes. However, preferably, all the drainage passages 104 are arranged against the lower wall panel of the middle compartment 103.

[0104] The vented fuel tank 100 further includes a first vent portion 105 that communicates the first compartment 101 with the intermediate compartment 103. For example, the first vent portion 105 is an opening formed in a first partition rib 111 disposed between the first compartment 101 and the intermediate compartment 103. The gas or fuel in the vented fuel tank 100 can flow between the first compartment 101 and the intermediate compartment 103 through the first vent portion 105. Preferably, the first vent portion 105 is disposed at the top of the first partition rib 111. When the fuel level in the first compartment 101 rises, the gas in the first compartment 101 can enter the intermediate compartment 103 via the first vent portion 105; and when the fuel level in the first compartment 101 rises to the position of the first vent portion 105, if fuel is continuously added to the first compartment 101, the fuel in the first compartment 101 can enter the intermediate compartment 103 via the first vent portion 105; when the fuel in the first compartment 101 leaves the first compartment 101 via the drainage passage 104, the gas in the intermediate compartment 103 can enter the first compartment 101 via the first vent portion 105.

[0105] The vented fuel tank 100 further includes a second vent portion 106 that fluidly communicates the second compartment 102 with the intermediate compartment 103. Specifically, the second vent portion 106 is a float valve 106 disposed in a second partition rib 112 between the second compartment 102 and the intermediate compartment 103. Preferably, the float valve 106 is disposed at the top of the second partition rib 112. When the fuel level in the second compartment 102 rises, the gas in the second compartment 102 can enter the intermediate compartment 103 via the float valve 106; and when the fuel level in the second compartment 102 reaches a preset position, the float valve 106 will close.

[0106] The vented fuel tank 100 further includes a secondary check valve 107 disposed between the second compartment 102 and the intermediate compartment 103. The secondary check valve 107 is configured to open towards the second compartment 102, that is, configured to be in one-way fluid communication with the second compartment 102. The fuel in the intermediate compartment 103 can enter the second compartment 102 via the secondary check valve 107. Preferably, the secondary check valve 107 is disposed near the bottom of the second partition rib 112 between the second compartment 102 and the intermediate compartment 103. It should be noted that in the drawings, the position of the secondary check valve 107 is higher than the second opening 104b of the drainage passage 104, but this does not mean that the secondary check valve 107 must be disposed higher than the second opening 104b of the drainage passage 104. In fact, most preferably, the secondary check valve 107 is disposed at the lowest point of the second partition rib 112 to facilitate the sufficient return of the fuel in the intermediate compartment 103 to the second compartment 102.

[0107] The vented fuel tank 100 further includes a vent assembly 108 which is installed on the lower wall panel of the intermediate compartment 103, enabling the vented fuel tank 100 to be in fluid communication with the outside atmosphere. The vent assembly 108 of the vented fuel tank 100 will be described in more detail below in conjunction with Figure 6 , and the vent assembly 108 of the vented fuel tank 100 will be described in more detail.

[0108] Figure 6 FIG. is a side view schematic diagram of the vent assembly 108 according to the present utility model. As Figure 6 shown, the vent assembly 108 includes a flame arrester 108a, a pressure stabilizing flare 108b, and a fuel tank vent 108d. The flame arrester 108a is installed on the fuel tank vent 108d, and the pressure stabilizing flare 108b is installed on the flame arrester 108a. A ventilation opening 108c is provided on the side wall of the pressure stabilizing flare 108b. The flame arrester 108a is configured to prevent external flames from entering the interior of the vented fuel tank 100, ensuring the safety of the aircraft. The pressure stabilizing flare 108b is configured to reduce the air flow velocity of the fuel tank vent 108d, avoiding violent pressure fluctuations inside the vented fuel tank 100 and making the pressure inside the vented fuel tank 100 stable.

[0109] More particularly, the pressure stabilizing flare 108b includes a first end and a second end opposite to the first end. The first end of the pressure stabilizing flare 108b is connected to the flame arrester 108a, and the second end is closed. The pressure stabilizing flare 108b is configured to gradually expand from the first end towards the second end, that is, the pressure stabilizing flare 108b is configured to be trumpet-shaped. The ventilation opening 108c of the pressure stabilizing flare 108b is positioned near the second end of the pressure stabilizing flare 108b. The trumpet-shaped pressure stabilizing flare 108b is beneficial to effectively reduce the air flow velocity of the fuel tank vent 108d, avoiding violent pressure fluctuations inside the vented fuel tank 100, thereby ensuring that the pressure inside the vented fuel tank 100 tends to be stable. In addition, configuring the second end to be closed is beneficial to avoiding dangerous amounts of fuel leakage caused by splashing into the vent assembly 108 when entering the intermediate compartment 103 via the first ventilation part 105.

[0110] In addition, it should be noted that when the fuel in the vented fuel tank 100 continuously increases until the fuel in the intermediate compartment 103 submerges the ventilation opening 108c of the pressure stabilizing flare 108b, the fuel will flow out of the aircraft via the ventilation opening 108c, preventing the fuel tank from overpressurizing in the event of a pressure refueling cut-off failure accident. It can be considered that the size of the vent assembly 108, particularly the size of the pressure stabilizing flare 108b and the position of the ventilation opening 108c, can be adjusted according to the design requirements for the fuel volume that the vented fuel tank 100 can accommodate.

[0111] The material of the pressure-stabilizing flared opening 108b is at least one of materials such as aluminum alloy and static-conductive composite materials that can be in direct contact with aviation fuel for a long time, so as to avoid ignition sources in the vented fuel tank 100 and extend the service life of the pressure-stabilizing flared opening 108b in the vented fuel tank 100.

[0112] Figure 7a is a schematic diagram of the vented fuel tank 100 without fuel according to the first embodiment of the present invention, while Figures 7b - 7d is a schematic diagram of the fuel flow in the vented fuel tank 100 according to the first embodiment of the present invention. Figure 7a The arrow in shows the gas flow direction in the vent assembly 108 of the vented fuel tank 100, while Figures 7b - 7d The arrow in shows the fuel flow direction in the vented fuel tank 100.

[0113] As Figure 7a shown, when there is no fuel in the vented fuel tank 100, the float valve 106 is in the open state, the secondary one-way valve 107 is in the closed state, the vent assembly 108 in the middle compartment 103 exchanges air with the outside normally, the pressure-stabilizing flared opening 108b performs a speed reduction and flow stabilization process on the air flow entering the vented fuel tank 100, the second compartment 102 near the wing root of the aircraft is connected to the middle compartment 103 through the float valve 106, the first compartment 101 near the wing tip of the aircraft is connected to the middle compartment 103 through the first vent part 105, and at the same time, the first compartment 101 and the second compartment 102 are also connected to each other through the drainage passage 104, so that each compartment in the vented fuel tank 100 can exchange air with the outside atmosphere normally.

[0114] As Figure 7b shown, when fuel starts to enter the vented fuel tank 100, for example, when the fuel in the main fuel tank enters the vented fuel tank 100 through the ventilation pipeline 110 due to large maneuvering actions of the aircraft: the fuel first enters the second compartment 102 near the wing root of the aircraft. As the fuel level rises, the fuel enters the first compartment 101 near the wing tip of the aircraft through the drainage passage 104, and there is no fuel in the middle compartment 103 where the vent assembly 108 is located, and the fuel is isolated from the vent assembly 108 by the partition rib plate. Therefore, even if the fuel in the vented fuel tank 100 shakes at this time, no fuel will spill out of the aircraft. When the aircraft attitude returns to normal, under the action of wing upward buckling, the fuel in the first compartment 101 flows back to the second compartment 102 through the drainage passage 104, and the fuel in the second compartment 102 flows back to the main fuel tank through the main one-way valve 109 at the bottom of the partition rib plate between the vented fuel tank 100 and the main fuel tank.

[0115] As Figure 7cAs shown in the figure, when there is a relatively large amount of fuel in the vented fuel tank 100: as the fuel level rises, when the fuel level reaches a preset position, the float valve 106 is in a closed state. The fuel that continues to enter the vented fuel tank 100 will not directly enter the middle compartment 103 from the second compartment 102, but will enter the first compartment 101 via the drainage passage 104 to fill the top space of the first compartment 101, so that the spaces of the second compartment 102 and the first compartment 101 are preferentially and fully utilized, reducing the amount of fuel entering the middle compartment 103 and the risk of dangerous fuel spillage. When the aircraft attitude returns to normal, under the action of the wing anhedral, the fuel in the first compartment 101 flows back to the second compartment 102 via the drainage passage 104, and the fuel in the middle compartment 103 also flows back to the second compartment 102 via the secondary one-way valve 107 at the bottom of the second partition plate. Finally, all the fuel in the second compartment 102 flows back to the main fuel tank through the main one-way valve 109 at the bottom of the partition rib between the vented fuel tank 100 and the main fuel tank.

[0116] As Figure 7d shown, when the vented fuel tank 100 continues to receive fuel during a pressure refueling cut-off failure accident: after the fuel fills the second compartment 102 and the first compartment 101, the fuel continuously enters the middle compartment 103 from the first vent part 105. When the fuel level in the middle compartment 103 covers the ventilation opening 108c of the pressure stabilizing flare 108b, the fuel flows out of the aircraft via the ventilation opening 108c to prevent the fuel tank from overpressurizing during a pressure refueling cut-off failure accident.

[0117] Figure 8 is a schematic diagram of the fuel flow in the vented fuel tank 100' according to the second embodiment of the present invention. In this embodiment, the vented fuel tank 100' preferably includes an auxiliary drainage passage 115 arranged at the top of the first compartment 101. One end of the auxiliary drainage passage 115 is connected to the first vent part 105, and the other end is an auxiliary drainage passage opening 115a near the wing tip of the aircraft. Due to the anhedral structure of the aircraft wing, the auxiliary drainage passage opening 115a is higher than the first vent part 105. When a relatively large amount of fuel enters the vented fuel tank 100', the space at the top of the first compartment 101 can be further utilized to improve the fuel holding capacity of the vented fuel tank 100' and reduce the risk of fuel overflowing from the ventilation opening 108c to the outside of the aircraft. The auxiliary drainage passage 115 can be, but is not limited to, a stringer or a pipeline or other drainage structures, and its material is a material that can be in direct contact with aviation fuel for a long time, including but not limited to aluminum alloy, static conductive composite materials, etc.

[0118] Figures 9a - 9c is a schematic diagram of the fuel flow in the vented fuel tank 100” according to the third embodiment of the present invention. In this embodiment, the ventilation passage 120 is configured to open to the vented fuel tank 100” of the first compartment 101. As the fuel enters, the fuel level and flow condition in the vented fuel tank 100” are asFigures 9a - 9c as shown

[0119] As Figure 9a shown, when fuel starts to enter the vented fuel tank 100", for example, when the fuel in the main fuel tank enters the vented fuel tank 100" via the vent pipe 120 due to large maneuvering of the aircraft: the fuel first enters the first compartment 101 near the wing tip of the aircraft, and enters the second compartment 102 near the wing root via the drainage passage 104, while there is no fuel in the middle compartment 103 where the vent assembly 108 is located, and the fuel is isolated from the vent assembly 108 by the partition rib. Therefore, even if the fuel in the vented fuel tank 100" sloshes at this time, no fuel will spill out of the aircraft. When the aircraft attitude returns to normal, under the action of wing dihedral, the fuel in the first compartment 101 flows back to the second compartment 102 via the drainage passage 104, and the fuel in the second compartment 102 flows back to the main fuel tank via the main one-way valve 109 at the bottom of the partition rib between the vented fuel tank 100" and the main fuel tank.

[0120] As Figure 9b shown, when there is more fuel in the vented fuel tank 100": as the fuel level rises, when the fuel level reaches the preset position, the float valve 106 is in the closed state, and the fuel that continues to enter the vented fuel tank 100" will not enter the middle compartment 103 from the second compartment 102, but continues to fill the top space of the first compartment 101, so that the spaces of the second compartment 102 and the first compartment 101 are preferentially and fully utilized, reducing the amount of fuel entering the middle compartment 103 and reducing the risk of dangerous fuel spillage. When the aircraft attitude returns to normal, under the action of wing dihedral, the fuel in the first compartment 101 flows back to the second compartment 102 via the drainage passage 104, and the fuel in the middle compartment 103 also flows back to the second compartment 102 via the secondary one-way valve 107 at the bottom of the second partition plate. Finally, all the fuel in the second compartment 102 flows back to the main fuel tank via the main one-way valve 109 at the bottom of the partition rib between the vented fuel tank 100" and the main fuel tank.

[0121] As Figure 9c shown, when the vented fuel tank 100" continues to be filled with fuel during a pressure refueling cut-off failure accident: after the second compartment 102 and the first compartment 101 are filled with fuel, the fuel continuously enters the middle compartment 103 from the first vent part 105. When the fuel level in the middle compartment 103 exceeds the ventilation opening 108c of the pressure stabilizing flare 108b, the fuel flows out of the aircraft via the ventilation opening 108c, preventing the fuel tank from overpressurizing during a pressure refueling cut-off failure accident.

[0122] Through the vented fuel tank of the present utility model, the following beneficial effects can be achieved:

[0123] 1. Through the drainage passage, the space of the first compartment and the second compartment can be fully utilized to accommodate the fuel, thereby improving the fuel holding capacity of the vented fuel tank, which is also conducive to preventing a dangerous amount of fuel from overflowing out of the aircraft;

[0124] 2. Through the drainage path, the fuel can be preferentially fed into the first and second compartments, thereby isolating the fuel in the vent tank from the vent assembly as much as possible to prevent a dangerous amount of fuel from spilling out of the aircraft;

[0125] 3. By means of pressure stabilization and expansion, the pressure in the vent tank becomes stable, thereby avoiding or reducing the risk of damage to components in the flow channel or overpressure in the tank caused by drastic or frequent pressure fluctuations in the vent tank.

[0126] In this document, the terms "include", "comprises" or any other variation thereof are intended to cover non-exclusive inclusion, so that a process, method, structure or device that includes a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, structure or device. In the absence of more restrictions, the elements defined by the sentence "includes..." do not exclude the presence of other identical elements in the process, method, structure or device that includes the elements.

[0127] The description of the utility model is given for the purpose of illustration and description, and is not intended to be exhaustive or to limit the utility model to the disclosed form. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described to better illustrate the principles and practical applications of the utility model and to enable those of ordinary skill in the art to understand the utility model and design various embodiments with various modifications suitable for specific uses.

Claims

1. A vent oil tank, the vent oil tank being used as a buffer area between a main oil tank of an aircraft and the outside atmosphere, the vent oil tank comprising a first compartment near the wing tip of the aircraft, a second compartment near the wing root of the aircraft, and an intermediate compartment between the first compartment and the second compartment, the vent oil tank also comprising a vent pipe connected to the main oil tank and a main non-return valve located between the second compartment and the main oil tank and opening toward the main oil tank, It is characterized in that The vent oil tank also includes: a drainage passage connecting the first compartment to the second compartment in fluid communication, a first vent that fluidically connects the first compartment to the middle compartment, a second vent connecting the second compartment to the middle compartment in fluid communication, a secondary one-way valve disposed between the second compartment and the intermediate compartment and opening toward the second compartment, and A vent assembly is installed on the lower wall plate of the middle compartment so that the vent oil tank is connected to the outside atmosphere.

2. The breather tank according to claim 1, characterized in that The vent assembly comprises a vent, a flame arrester mounted on the vent, and a pressure-stabilizing expansion port mounted on the flame arrester. The pressure-stabilizing expansion port is communicated with the flame arrester, and a ventilation opening is arranged on a side wall of the pressure-stabilizing expansion port.

3. The breather tank according to claim 1, characterized in that The drainage passage is arranged in or on the lower wall plate of the intermediate compartment.

4. The breather tank according to claim 3, characterized in that The drainage passage includes a first opening opened to the first compartment and a second opening opened to the second compartment, wherein the first opening is located at the bottom of a first partition rib between the first compartment and the middle compartment, and / or the second opening is located at the bottom of a second partition rib between the second compartment and the middle compartment.

5. The breather tank according to claim 1, characterized in that The drainage route is composed of a long stringer or a pipeline.

6. The breather tank according to claim 1, characterized in that The first vent is located at the top of a first partition rib between the first compartment and the middle compartment, and / or the second vent is located at the top of a second partition rib between the second compartment and the middle compartment.

7. The breather tank according to claim 1, characterized in that The vent oil tank further comprises an auxiliary drainage passage arranged on the top of the first compartment, one end of the auxiliary drainage passage is connected to the first vent portion, and the other end of the auxiliary drainage passage is close to the wing tip of the aircraft.

8. The breather tank according to claim 1, characterized in that The second vent is a float valve, and the float valve is configured to be closed when the liquid level in the second compartment reaches a preset position.

9. A breather tank according to any one of claims 1 to 8, characterized in that The material of the drainage passage is at least one of aluminum alloy and electrostatically conductive composite material.

10. A vent assembly, the vent assembly being used for a vented fuel tank of an aircraft, the vent assembly comprising a vent and a flame arrester mounted on the vent, It is characterized in that The vent assembly also includes a pressure-stabilizing expansion port installed on the flame arrester, the pressure-stabilizing expansion port is communicated with the flame arrester, and a ventilation opening is arranged on the side wall of the pressure-stabilizing expansion port.

11. The vent assembly according to claim 10, characterized in that The pressure-stabilizing expansion port includes a first end and a second end opposite to the first end, the first end is connected to the flame arrester, the second end is a closed end, and the pressure-stabilizing expansion port is configured to gradually expand from the first end toward the second end.

12. The vent assembly according to claim 11, characterized in that The ventilation opening is located proximate the second end.

13. The vent assembly according to claim 10, wherein: The material of the voltage-stabilizing expansion is at least one of aluminum alloy and static-conductive composite material.

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