A device for integrating a bypass pressure relief valve on a vent valve

Abstract

The utility model discloses a device integrated bypass pressure relief valve on breather valve includes casing, breather valve, pressure relief valve, and breather valve includes valve seat, steel ball, floater subassembly, and pressure relief valve includes valve, spring, screw plug, and breather valve and bypass pressure relief valve share inlet, outlet, partial flow channel, and floater subassembly is under the gravity effect of itself, and the floater valve opens breather, realizes the pressure difference balance in oil tank inside and outside, in big attitude inclination state, leans on steel ball swing, and lifts the floater subassembly floater valve and closes, prevents fuel overflow, and the floater subassembly can realize closing under the fuel buoyancy effect, prevents fuel overflow, and pressure relief valve adopts direct-acting safety valve, and the sealing structure adopts dovetail groove cover sealing ring taper surface sealing, when the oil tank pressure reaches the specified value, and pressure relief valve valve opens and discharges oil, prevents the overpressure of oil tank. The device has the characteristics of compact structure, light weight, multi -functional.

Description

Technical Field

[0001] This utility model belongs to the technical field of fuel system ventilation subsystem, specifically relating to a device that integrates a bypass pressure relief valve on a ventilation valve. Background Technology

[0002] In the field of closed-cavity pressure control, such as aircraft fuel systems and hydraulic systems, maintaining pressure balance inside and outside the cavity and preventing overpressure are core requirements for ensuring system safety. Taking aircraft fuel systems as an example, fuel tanks need to maintain pressure balance under different flight altitudes (e.g., from ground level to 12,000 meters), attitudes (e.g., climb, dive), and operating conditions (e.g., fuel transfer, refueling) to prevent negative pressure from causing tank structural collapse or positive pressure from causing fuel leakage. Overpressure protection is also needed to address the risk of sudden pressure increases in extreme situations (e.g., fuel transfer system shutdown failure, venting line blockage).

[0003] In existing technologies, pressure balancing and overpressure protection functions are typically achieved through separate vent valves and pressure relief valves. This results in complex structures, large space requirements, and limited adaptability. The limited space in core areas such as aircraft wing fuel tanks and hydraulic tanks not only reduces fuel storage capacity but also increases the risk of interference between pipelines and structural components. Separate components require independent periodic calibration (e.g., vent valve pressure threshold calibration, pressure relief valve sealing tests), increasing maintenance time by more than 50% compared to integrated solutions. Furthermore, the number of pipeline joints between components (e.g., the flange connection from the vent valve outlet to the pressure relief valve inlet) reaches 4-6, increasing potential leakage points by three times compared to integrated designs, which can easily lead to fire risks in the fuel system. Utility Model Content

[0004] To meet the requirements of achieving fuel tank pressure balance and preventing fuel spillage during large aircraft attitudes, while also avoiding the risk of fuel tank overpressure when the transfer fuel shut-off fails, a device integrating a bypass pressure relief valve into the vent valve is proposed. This device is installed on top of the fuel tank, with the vent valve and bypass pressure relief valve sharing inlet, outlet, and part of the flow path. Under its own weight, the float valve opens to allow ventilation, achieving pressure balance between the inside and outside of the fuel tank. During large attitude tilting, the oscillating steel ball pushes the float valve to close, preventing fuel spillage. The float valve can also close under the buoyancy of the fuel, preventing further fuel spillage. The pressure relief valve is a direct-acting safety valve with a dovetail groove sealing ring and conical surface seal. When the fuel tank pressure reaches a specified value, the pressure relief valve opens to discharge fuel, preventing fuel tank overpressure.

[0005] Specifically, this utility model provides a device for integrating a bypass pressure relief valve on a vent valve, including a housing, a vent valve, and a pressure relief valve, with the vent valve and pressure relief valve housed within the housing; the vent valve includes a valve seat, a steel ball, and a float assembly, and the pressure relief valve includes a valve, a spring, and a screw plug; the valve seat is threadedly sealed to the inner bottom of the housing, forming a vent chamber in the lower part of the housing; the float assembly is installed within the valve seat and moves flexibly; the steel ball is positioned between the float assembly and the valve seat; the float assembly includes a sealing gasket and a float, forming a sealing pair with the housing; The shell has an inlet at the bottom and an outlet at the top. A bypass pipe is provided on one side of the shell. The upper opening of the bypass pipe is connected to the pressure relief chamber, and the lower opening of the bypass pipe is connected to the venting chamber. An axial channel is provided at the top of the venting chamber. The top of the axial channel is connected to the outlet, and the bottom of the venting chamber is connected to the inlet. A through hole is provided at the side end of the axial channel to connect to the pressure relief chamber. Under its own weight, the vent valve opens the float assembly, connecting the vent chamber to the axial channel. The valve of the pressure relief valve and the housing are sealed by the conical surface under the action of the spring and the screw plug, thus achieving pressure balance between the inside and outside of the oil tank. In a large tilted position, the steel ball swings, lifting the float assembly to close the vent chamber and axial channel. Under the buoyancy of the fuel, the float assembly and axial channel form a planar seal. The valve automatically aligns, minimizing the impact of the mechanical environment and achieving reliable sealing. The pressure relief valve's valve and housing are sealed with a conical surface by the spring and screw plug to prevent fuel spillage. When the oil tank pressure reaches the specified value, the pressure relief valve separates from the housing, opening to drain oil and prevent overpressure in the oil tank. The valve seat has a through hole one along the axis at the bottom, a support cone surface on the inner side of the valve seat, a steel ball that can roll freely on the support cone surface, and a through hole two that is perpendicular to the support cone surface and faces outward.

[0006] Furthermore, the bottom of the valve seat is provided with an annular groove, the area of ​​which is larger than the minimum channel of the product.

[0007] Furthermore, the valve includes a cone and a guide rod for guiding purposes. The vertical cone has a dovetail groove on its conical surface, and a sealing ring is fitted inside the dovetail groove. The top of the cone has an annular groove along the bottom of the guide rod to meet the flow rate and flow resistance requirements of the medium. The outer edge of the cone has a convex ring along the circumference to increase the pressure sensing area, reliably sense fuel pressure to open, achieve maximum opening, and reduce flow resistance.

[0008] Furthermore, the screw plug has a stepped structure, including a first stepped portion, a second stepped portion, and a third stepped portion with gradually increasing diameter. The second stepped portion connects the first stepped portion and the third stepped portion. The third stepped portion is provided with a thread that connects to the internal thread of the housing. The bottom of the first stepped portion has a guide groove along the axial direction to cooperate with the guide rod. The spring is sleeved on the outside of the first stepped portion, with one end placed in the annular groove and the other end abutting against the gasket and then against the side of the second stepped portion. A through hole is provided between the side of the second stepped portion and the guide groove. An annular groove is provided on the end face of the second stepped portion to cooperate with the sealing ring. The screw plug fixes and compresses the spring, giving the spring initial elasticity. The opening pressure requirement is met by adding or removing gaskets. The guide connection with the inner cavity of the housing provides a more precise movement pair for the valve guide rod. The sealing ring is sleeved on the piston, forming a hole-axis seal with the housing to achieve external sealing and reliable sealing. The through hole in the inner wall of the screw plug effectively avoids the formation of a dead cavity when the valve is opened, resulting in insufficient valve opening. It provides a valve limiting end to prevent the spring from compressing and coiling. The spring provides the sealing force of the valve. The preload is calculated based on the opening pressure and the pressure-sensing area. The design stiffness is low, which can greatly increase the opening degree of the valve.

[0009] Furthermore, the housing is a one-piece molded structure made of aerospace aluminum alloy or titanium alloy. As a system connection interface, the housing can provide a medium channel, a conical sealing surface, a flat sealing surface, and internal thread fixing. It is the main structural component. The internal opening position design can achieve the purpose of smooth flow and reduce fuel flow resistance. At the same time, it directly solves the installation and adaptation problem in narrow spaces such as wing fuel tanks, taking into account both lightweight and corrosion resistance.

[0010] Furthermore, the surface roughness Ra of the conical portion is ≤0.8μm to ensure sealing reliability under low pressure differential. This utility model provides a device that integrates a bypass pressure relief valve on a vent valve. Under the premise that the vent valve achieves fuel tank pressure balance and prevents fuel spillage during large aircraft attitudes, the integrated bypass pressure relief valve adds the function of draining fuel from the fuel tank when the transfer fuel shut-off fails, thereby avoiding fuel tank overpressure and ensuring fuel tank safety.

[0011] The beneficial effects of this utility model are: 1. Under the premise of achieving fuel tank pressure balance and preventing fuel spillage during large aircraft attitudes, a bypass pressure relief valve is integrated into the vent valve to add the function of draining fuel from the fuel tank when the transfer fuel shut-off fails.

[0012] 2. The product is designed to be lightweight and compact. The vent valve and bypass pressure relief valve share the same inlet, outlet and part of the flow channel, which allows the product to be multifunctional while keeping its own weight light. Attached Figure Description

[0013] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments conforming to the present invention and, together with the description, serve to explain the principles of the present invention. It is obvious that the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0014] Figure 1 A schematic diagram of the device for integrating a bypass pressure relief valve on a vent valve provided by this utility model; Figure 2 A schematic diagram of the device for integrating a bypass pressure relief valve on a vent valve provided by this utility model in a large tilt state. Figure 3 A schematic diagram of the valve seat structure provided by this utility model; Figure 4 A top view of the valve seat provided for this utility model; Figure 5 A bottom view of the valve seat provided for this utility model; Figure 6 A schematic diagram of the valve structure provided by this utility model; Figure 7 A schematic diagram of the screw plug structure provided by this utility model; Wherein: 1-shell, 101-ventilation chamber, 102-pressure relief chamber, 103-bypass pipe, 104-axial channel, Vent valve, 201-valve seat, 202-steel ball, 203-float assembly, 201.1-through hole one, 201.2-support cone surface, 201.3-through hole two, 201.4-annular groove one. Pressure relief valve, 301-valve, 302-spring, 303-screw plug, 304-sealing ring one, 305-gasket, 306-sealing ring two, 301.1-cone, 301.2-guide rod, 301.1.1-dovetail groove, 301.1.2-ring groove two, 301.1.3-convex ring, 303.1-first step, 303.2-second step, 303.3-third step, 303.4-guide hole, 303.5-through hole three, 303.2.1-ring groove three. Detailed Implementation

[0015] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make the present invention more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art.

[0016] Please see Figure 1-7The figure shows a schematic diagram of the device structure of the vent valve integrated with the bypass pressure relief valve provided by the present invention, including a housing 1, a vent valve 2, and a pressure relief valve 3, wherein the vent valve 2 and the pressure relief valve 3 are placed inside the housing 1; wherein the vent valve 2 includes a valve seat 201, a steel ball 202, and a float assembly 203, and the pressure relief valve 3 includes a valve 301, a spring 302, and a screw plug 303; The valve seat 201 is threadedly sealed to the inner bottom of the housing 1, forming a venting chamber 101 in the lower part of the housing 1. The float assembly 203 is installed in the valve seat 201 and moves flexibly. The steel ball 202 is placed between the float assembly 203 and the valve seat 201. The valve 301 is sealed to the inner conical surface of the housing 1, the screw plug 303 is threadedly sealed to the upper inner side of the housing 1, and the spring 302 is placed in the pressure relief cavity 102 formed between the valve 301 and the screw plug 303. A gasket 305 is provided between the screw plug 303 and the spring 302. The housing 1 has an inlet A at the bottom and an outlet B at the top. A bypass pipe 103 is provided on one side of the housing 1. The upper opening of the bypass pipe 103 is connected to the pressure relief chamber 102, and the lower opening of the bypass pipe 103 is connected to the venting chamber 101. An axial channel 104 is provided at the top of the venting chamber 101. The top of the axial channel 104 is connected to the outlet B, and the bottom of the venting chamber 101 is connected to the inlet A. A through hole 105 is provided on the side of the axial channel 104 and is connected to the pressure relief chamber 102. The pressure relief outlet of the bypass pressure relief valve 3 shares the same inlet and outlet interfaces as the venting valve 2. The flow channel length is shortened and there are no bends, the flow resistance is reduced, and the overall volume is reduced.

[0017] The valve seat 201 has a through hole 201.1 along its axis at the bottom to ensure unobstructed flow. A supporting conical surface 201.2 is provided on the inner side of the valve seat 201, on which the steel ball 202 can roll freely. A through hole 201.3 is provided perpendicular to the supporting conical surface 201.2 and extending outwards. The bottom of the valve seat 201 also has an annular groove 201.4, the area of ​​which is larger than the minimum channel of the product, to meet the flow rate and flow resistance requirements of the medium.

[0018] The valve 301 includes a cone portion 301.1 and a guide rod 301.2. The cone surface of the vertical cone portion 301.1 is provided with a dovetail groove 301.1.1, and a sealing ring 304 is fitted inside the dovetail groove 301.1.1. The top of the cone portion 301.1 is provided with an annular groove 301.1.2 along the bottom end of the guide rod 301.2 to meet the requirements of medium flow rate and flow resistance. The outer edge of the cone portion 301.1 is provided with a convex ring 301.1.3 along the circumferential direction, which can increase the pressure sensing area, reliably sense fuel pressure to open, achieve the maximum opening degree, and reduce flow resistance.

[0019] The plug 303 has a stepped structure, including a first stepped portion 303.1, a second stepped portion 303.2, and a third stepped portion 303.3 with gradually increasing diameters. The second stepped portion 303.2 connects the first stepped portion 303.1 and the third stepped portion 303.3. The third stepped portion 303.3 is provided with threads that connect with the internal threads of the housing 1. The bottom of the first stepped portion 303.1 has a guide hole 303.4 that mates with the guide rod 301.2. The spring 302 is sleeved on the outside of the first stepped portion 303.1, with one end placed in the second annular groove 301.1.2 and the other end abutting against the gasket 305 and then against the side of the second stepped portion 303.2. A through hole 303.5 is provided between the side of the second stepped portion 303.2 and the guide hole 303.4. The end face of the second stepped portion 303.2 has an annular groove 303.2.1 that mates with the second sealing ring 306. The screw plug 303 secures the spring 302, giving it initial elasticity. The opening pressure requirements are met by adding or removing shims 305. It connects to the inner cavity of the housing 1, providing a more precise kinematic pair for the valve guide rod 301.2. A second sealing ring 306 is fitted onto the screw plug 303, forming a hole-shaft seal with the housing, achieving a reliable external seal. A third through hole 303.5 on the inner wall of the screw plug 303 effectively prevents the valve 301 from forming a dead space when it opens, thus avoiding insufficient opening of the valve 301. It also provides a limiting end for the valve 301, preventing the spring 302 from compressing and coiling. The spring 302 provides the sealing force of the valve 301. The preload of the spring 302 is calculated based on the opening pressure and the pressure-sensing area, resulting in a low design stiffness that greatly increases the valve's opening degree.

[0020] The housing 1 is an integrally molded structure made of aerospace aluminum alloy or titanium alloy. As a system connection interface, the housing can provide a medium channel, a conical sealing surface, a flat sealing surface and internal thread fixing. It is the main structural component. The internal opening position design can achieve the purpose of smooth flow and reduce fuel flow resistance. At the same time, it directly solves the installation and adaptation problem in narrow spaces such as wing fuel tanks, and takes into account both lightweight and corrosion resistance.

[0021] The preload of the spring 302 is calculated based on the opening pressure and the pressure-sensing area.

[0022] The surface roughness Ra of the 301.1 cone portion is ≤0.8μm, ensuring sealing reliability under low pressure differential.

[0023] Under normal conditions, the vent valve 2 opens the float assembly 203 downwards under its own weight, the vent chamber 101 connects with the axial channel 104, and the valve 301 of the pressure relief valve 3 and the housing 1 are sealed on the conical surface under the action of the spring 302 and the screw plug 303, so as to achieve the balance of pressure difference inside and outside the oil tank. In a large tilt state, the steel ball 202 swings and lifts the float assembly 203, causing the vent chamber 101 and the axial channel 104 to close. Under the action of fuel buoyancy, the float assembly 203 and the axial channel 104 are sealed in a plane. The valve 301 of the pressure relief valve 3 and the housing 1 are sealed in a conical surface under the action of the spring 302 and the screw plug 303 to prevent fuel from overflowing. When the oil tank pressure continues to rise to the specified value, the valve 301 of the pressure relief valve 3 separates from the housing 1, the flow channel is fully opened, and oil is discharged to achieve instantaneous large flow pressure relief and prevent the oil tank from overpressure. At the same time, the screw plug 303 is threadedly connected to the housing 1 to limit it and avoid excessive opening that could cause the spring 302 to fail.

[0024] After the pressure is released, under the action of spring 302, valve 301 is forced back to seal with housing 1 again. At the same time, the protruding ring 301.1.3 on valve 301 limits it to ensure that the sealing position is not deviated after each reset.

[0025] Therefore, while ensuring fuel tank pressure balance and preventing fuel spillage during large aircraft attitudes, a bypass pressure relief valve is integrated into the vent valve. When the transfer fuel shut-off fails, it adds the function of draining fuel from the fuel tank to prevent overpressure and ensure the safety of the fuel tank.

[0026] The above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Any modifications or equivalent substitutions made by those skilled in the art to the technical solution of this utility model, as long as they do not depart from the spirit and scope of the technical solution of this utility model, are all covered within the scope of the claims of this utility model.

Claims

1. A device for integrating a bypass pressure relief valve onto a vent valve, characterized in that: Includes housing (1), vent valve (2), and pressure relief valve (3), with the vent valve (2) and pressure relief valve (3) housed inside housing (1); The vent valve (2) includes a valve seat (201), a steel ball (202), and a float assembly (203); the pressure relief valve (3) includes a valve (301), a spring (302), and a screw plug (303). The valve seat (201) is threadedly sealed to the inner bottom of the housing (1), forming a venting chamber (101) at the bottom of the housing (1). The float assembly (203) is installed in the valve seat (201) and moves flexibly. The steel ball (202) is placed between the float assembly (203) and the valve seat (201). The valve (301) is sealed to the inner conical surface of the housing (1), the screw plug (303) is connected to the upper inner side of the housing (1) by a threaded seal, and the spring (302) is placed in the pressure relief cavity (102) formed between the valve (301) and the screw plug (303). A gasket (305) is provided between the screw plug (303) and the spring (302). The housing (1) has an inlet (A) at the bottom and an outlet (B) at the top. A bypass pipe (103) is provided on one side of the housing (1). The upper opening of the bypass pipe (103) is connected to the pressure relief chamber (102), and the lower opening of the bypass pipe (103) is connected to the venting chamber (101). An axial channel (104) is provided at the top of the venting chamber (101). The top of the axial channel (104) is connected to the outlet (B), and the bottom of the venting chamber (101) is connected to the inlet (A). A through hole (105) is opened at the side end of the axial channel (104) and is connected to the pressure relief chamber (102). Under its own gravity, the vent valve (2) opens the float assembly (203), and the vent chamber (101) connects with the axial channel (104). The valve (301) of the pressure relief valve (3) and the housing (1) are sealed by the conical surface under the action of the spring (302) and the screw plug (303) to achieve the balance of pressure difference inside and outside the oil tank. In a large tilt state, the steel ball (202) swings and lifts the float assembly (203), causing the vent chamber (101) and the axial channel (104) to close. Under the action of fuel buoyancy, the float assembly (203) and the axial channel (104) are sealed in a plane. The valve (301) of the pressure relief valve (3) and the housing (1) are sealed in a conical surface under the action of the spring (302) and the screw plug (303) to prevent fuel from overflowing. When the oil tank pressure reaches the specified value, the valve (301) of the pressure relief valve (3) separates from the housing (1) and opens to drain oil, preventing the oil tank from overpressure.

2. The device for integrating a bypass pressure relief valve on a vent valve according to claim 1, characterized in that: The valve seat (201) has a through hole 1 (201.1) at the bottom along the axis, and a support cone surface (201.2) is provided on the inner side of the valve seat (201). The steel ball (202) can roll freely on the support cone surface (201.2). A through hole 2 (201.3) is provided perpendicular to the support cone surface (201.2) and extends outward.

3. The device for integrating a bypass pressure relief valve on a vent valve according to claim 1, characterized in that: The bottom of the valve seat (201) is also provided with an annular groove (201.4), the area of ​​which is larger than the minimum channel of the product.

4. The device for integrating a bypass pressure relief valve on a vent valve according to claim 1, characterized in that: The valve (301) includes a cone (301.1) and a guide rod (301.2). The cone surface of the vertical cone (301.1) is provided with a dovetail groove (301.1.1). A sealing ring (304) is fitted inside the dovetail groove (301.1.1). The top of the cone (301.1) is provided with an annular groove (301.1.2) along the bottom end of the guide rod (301.2). The outer edge of the cone (301.1) is provided with a convex ring (301.1.3) along the circumferential direction.

5. The device for integrating a bypass pressure relief valve on a vent valve according to claim 4, characterized in that: The plug (303) has a stepped structure, including a first stepped portion (303.1), a second stepped portion (303.2), and a third stepped portion (303.3) with gradually increasing diameter. The second stepped portion (303.2) connects the first stepped portion (303.1) and the third stepped portion (303.3). The third stepped portion (303.3) is provided with threads that connect with the internal threads of the housing (1). The bottom of the first stepped portion (303.1) is provided with a guide hole (303) axially inward. 4) In conjunction with the guide rod (301.2), the spring (302) is sleeved on the outside of the first step (303.1), with one end placed in the second annular groove (301.1.2) and the other end abutting against the gasket (305) and then against the side of the second step (303.2). A through hole (303.5) is provided between the side of the second step (303.2) and the guide hole (303.4). The end face of the second step (303.2) is provided with an annular groove (303.2.1) that cooperates with the sealing ring (306).

6. The device for integrating a bypass pressure relief valve on a vent valve according to claim 1, characterized in that: The shell (1) is a one-piece molded structure.

7. The device for integrating a bypass pressure relief valve on a vent valve according to claim 1, characterized in that: The preload of the spring (302) is calculated based on the opening pressure and the pressure-sensing area.

8. The device for integrating a bypass pressure relief valve on a vent valve according to claim 4, characterized in that: The surface roughness Ra of the cone (301.1) is ≤0.8μm.

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