An unmanned underwater vehicle fuel system temperature compensated expansion tank structure

Abstract

The present application relates to the technical field of unmanned underwater vehicle fuel system, and particularly relates to a temperature compensation expansion tank structure of unmanned underwater vehicle fuel system, which comprises a tank body, a fuel interface and a seawater pressure interface, the fuel interface is arranged on one side of the tank body, the seawater pressure interface is arranged on the end face of the other side of the tank body, the tank body is a sealed pressure-resistant shell, a floating baffle is slidably sleeved in the tank body, the volume of the fuel cavity is adjusted through the sliding sealing cooperation between the tank body and the floating baffle, the tank body is divided into a fuel cavity and a compensation cavity by the floating baffle, the inner wall of the tank body moves axially, the position between the fuel cavity and the compensation cavity is adjusted when the fuel temperature changes or the fuel volume changes, the internal volume of the fuel cavity changes with the displacement of the floating baffle, the insufficient internal space or pressure change of the fuel cavity caused by the change of the fuel volume is reduced, the fuel cavity and the compensation cavity are separated, and the possibility that the fuel enters the compensation cavity through the cooperation gap between the floating baffle and the tank body is reduced.

Description

Technical Field

[0001] This invention relates to the field of fuel system technology for unmanned underwater vehicles, and more specifically to a temperature-compensated expansion tank structure for a fuel system of an unmanned underwater vehicle. Background Technology

[0002] The fuel system of an unmanned underwater vehicle (UUV) is typically equipped with an expansion tank for storing, transporting, and compensating for changes in fuel volume. During underwater navigation, the fuel temperature changes with the ambient temperature, equipment operating status, and fuel consumption, resulting in changes in fuel volume. At the same time, the expansion tank is subjected to seawater pressure that varies with the diving depth. Therefore, the expansion tank usually needs to adapt to changes in fuel volume and external seawater pressure while maintaining the fuel chamber sealed.

[0003] Existing expansion compensation structures in the fuel systems of unmanned underwater vehicles mainly include two types: airbag expansion tanks and piston expansion tanks. The expansion tank is usually connected to the fuel pipeline or fuel storage chamber to accommodate the volume changes of fuel caused by temperature changes, fuel consumption, and changes in diving depth, and to compensate for pressure changes inside the fuel system.

[0004] Airbag-type expansion tanks typically have rubber airbags inside the tank. The elastic deformation of the rubber airbags changes their internal volume to compensate for changes in fuel volume. Since the rubber airbags need to be in contact with fuel for a long time, the fuel may cause swelling, softening, or aging of the airbag material during long-term operation of the unmanned underwater vehicle. In the high-pressure environment of the deep sea, the airbags are also subject to repeated compression and recovery, which can easily lead to problems such as material fatigue, local thinning, or damage. When the airbag deforms unevenly, breaks, or loses elasticity, its effective compensation volume will change. Furthermore, the assembly, replacement, and maintenance of the airbags and the tank usually require the disassembly of related components, making maintenance operations relatively complex and difficult to meet the requirements of long-term underwater operation and maintenance convenience for unmanned underwater vehicles.

[0005] Piston-type expansion tanks typically have a single piston or piston-type baffle inside the tank, dividing the tank into a fuel side and a gas side. The piston moves axially within the tank to accommodate changes in fuel volume. In existing piston-type structures, the piston is usually in direct contact with the fuel. Sliding fit parts and seals are provided between the outer circumference of the piston and the inner wall of the tank. The fuel system of an unmanned underwater vehicle may contain a small amount of water, impurities, or oil deposits. These substances may enter the fit gap between the outer circumference of the piston and the inner wall of the tank under the influence of fuel flow, vibration, or pressure changes, causing contamination of the sliding parts, local pressure on the seals, or increased frictional resistance, which in turn makes the piston move unevenly or even causes jamming.

[0006] Therefore, it is necessary to improve the expansion compensation structure of the fuel system of unmanned underwater vehicles to reduce the failure risk of compensation components under long-term fuel immersion and deep-sea pressure environment, and to improve the pressure buffer and isolation structure when external seawater pressure changes are transmitted to the fuel side. Summary of the Invention

[0007] This invention addresses the technical problems existing in the prior art by providing a temperature-compensated expansion tank structure for the fuel system of an unmanned underwater vehicle.

[0008] The technical solution of this invention to solve the above-mentioned technical problems is as follows: A temperature compensation expansion tank structure for an unmanned underwater vehicle (UUV) fuel system includes a tank body, a fuel inlet, and a seawater pressure inlet. The fuel inlet is located on one side of the tank body, and the seawater pressure inlet is located on the other end face of the tank body. The tank body is a sealed pressure-resistant shell. A floating partition is slidably fitted inside the tank body, dividing the interior of the tank body into a fuel chamber and a compensation chamber. The floating partition is slidably sealed to the inner wall of the tank body. A mounting flange is provided near the seawater pressure inlet of the tank body. A pressure balancing membrane is internally threaded into the mounting flange. The pressure balancing membrane separates the interior of the tank body from the flow channel of the seawater pressure inlet. One end of the flow channel of the seawater pressure inlet is connected to the outside of the pressure balancing membrane, and the other end is connected to the external seawater environment of the UUV. A seawater filter is embedded in the flow channel of the seawater pressure inlet. A one-way valve is provided on the flow channel of the seawater pressure inlet. The one-way valve is directed from the outside of the seawater pressure inlet to the outside of the pressure balancing membrane.

[0009] In a preferred embodiment, the floating partition includes a first annular partition and a second annular partition, the first annular partition and the second annular partition are disposed opposite to each other, a limiting ring block is provided between them, and an annular seal is provided in the gap between the limiting ring block and the first annular partition and the second annular partition.

[0010] In a preferred embodiment, the first annular partition plate has an outer flow channel circulation cavity at one edge facing the second annular partition plate, and an air hole A is provided at the bottom of one end of the outer flow channel circulation cavity.

[0011] In a preferred embodiment, the first annular partition plate has a middle ring region in the middle of the side facing the second annular partition plate, and the middle ring region has an air hole B.

[0012] In a preferred embodiment, an inner circulation cavity is provided at the center of the side of the first annular partition plate facing the second annular partition plate. An air hole C is provided on the bottom end face of the inner circulation cavity. An air cavity is formed between the first annular partition plate and the second annular partition plate. The air holes A, B and C are all in communication with the air cavity.

[0013] In a preferred embodiment, a sealing abutment ring is connected to the middle of the inner sidewall of the second annular partition plate. The second annular partition plate is provided with a through hole coaxial with the sealing abutment ring. A compression spring is connected to one side of the outer arc surface of the sealing abutment ring, and an outer cylinder section is connected to the other end of the compression spring. The outer cylinder section is coaxially arranged with the sealing abutment ring.

[0014] In a preferred embodiment, the outer cylinder section is abutted against a sealing abutment ring by a compression spring, and both the outer cylinder section and the sealing abutment ring are provided with air channels at their axial centers. An annular air frame is sleeved on the outer arc surface of the outer cylinder section.

[0015] In a preferred embodiment, a pin is provided in the middle of the inner wall of the annular air frame, and a conical spring is connected to the outer arc surface of the pin. The other end of the conical spring is connected to an inner cylinder section, and a cavity communicating with the air passage is formed between the outer arc surface of the inner cylinder section and the inner arc surface of the outer cylinder section.

[0016] In a preferred embodiment, an air vent is provided on one side of the outer arc surface of the annular air frame. The air vent communicates with the air cavity and corresponds to the air hole A, air hole B and air hole C.

[0017] In a preferred embodiment, a flexible pressure-resistant diaphragm is connected to the front end of the inner arc face of the pressure balancing membrane. The flexible pressure-resistant diaphragm is located on the side of the pressure balancing membrane opposite to the inside of the tank. The flow channel of the seawater pressure interface is connected to the outside of the pressure balancing membrane.

[0018] The beneficial effects of this invention are: The volume of the fuel chamber is adjusted by the sliding seal between the housing and the floating baffle. The floating baffle divides the inside of the housing into a fuel chamber and a compensation chamber, and can move axially along the inner wall of the housing. When the fuel temperature or fuel volume changes, the floating baffle can adjust its position between the fuel chamber and the compensation chamber, so that the internal volume of the fuel chamber changes with the displacement of the floating baffle. This reduces the possibility of insufficient internal space or pressure changes in the fuel chamber caused by changes in fuel volume. The sliding seal between the floating baffle and the inner wall of the housing can also separate the fuel chamber and the compensation chamber, reducing the possibility of fuel entering the compensation chamber through the gap between the floating baffle and the housing.

[0019] The combination structure of the first annular partition, the second annular partition, the limiting ring block, and the annular seal limits the installation gap and relative position inside the floating partition. The limiting ring block is set between the first annular partition and the second annular partition to maintain the relative distance between them. The annular seal is set in the gap between the limiting ring block and the two annular partitions to maintain the corresponding sealing fit when the floating partition moves along the inner wall of the box. The outer flow channel circulation chamber, the middle ring area, and the inner flow circulation chamber on the first annular partition are connected to the air chamber through air holes A, B, and C, respectively, so that the gas in the compensation chamber can flow between different radial areas, which is beneficial to adapting to the gas redistribution when the air chamber volume changes.

[0020] The relative positions of the gas passages are adjusted by the coaxial elastic cooperation of the sealing ring, outer cylinder section, inner cylinder section, compression spring, and conical spring. The outer cylinder section abuts against the sealing ring under the action of the compression spring, and the inner cylinder section is connected to the pin on the annular gas frame by the conical spring. A gas flow cavity is formed between the outer cylinder section and the inner cylinder section. When the floating baffle moves or the gas pressure inside the gas cavity changes, the outer cylinder section can move axially relative to the sealing ring, and the inner cylinder section can move accordingly relative to the outer cylinder section. The compression spring and the conical spring respectively generate compression, extension, or reset actions. Through the cooperation between the cylinder section and the spring, the air inlet, the gas passage of the outer cylinder section, the gas passage of the sealing ring, and the gas cavity can be kept in corresponding communication, and the axial displacement range of the outer cylinder section and the inner cylinder section is limited to a certain extent.

[0021] The system utilizes a combination of a pressure balancing membrane, a flexible pressure-resistant diaphragm, a seawater filter, and a one-way valve to transmit external seawater pressure to the compensation chamber. The pressure balancing membrane is installed inside the mounting flange of the housing, separating the interior of the housing from the flow channel of the seawater pressure interface. This allows external seawater to act on the outside of the pressure balancing membrane without directly entering the housing. The seawater filter is located within the flow channel of the seawater pressure interface to filter the seawater entering the outside of the pressure balancing membrane. The one-way valve restricts the flow of seawater from the outside of the seawater pressure interface to the outside of the pressure balancing membrane, reducing the impact of reverse flow of seawater in the flow channel on the pressure transmission process. The flexible pressure-resistant diaphragm is connected to the side of the pressure balancing membrane facing the interior of the housing and can shift or deform with pressure changes on both sides of the pressure balancing membrane. This allows external seawater pressure to be transmitted to the compensation chamber through the diaphragm structure, thus coordinating with the axial movement of the floating baffle. Attached Figure Description

[0022] Figure 1 This is a partial cross-sectional view of the internal structure of the housing of the present invention; Figure 2 This is a cross-sectional view of the internal structure of the floating partition of the present invention; Figure 3This is a schematic diagram of the overall side view structure of the present invention; Figure 4 This is a front view of the flow channel circulation cavity of the present invention; Figure 5 This is a cross-sectional airflow trend diagram of the annular air frame of the present invention; Figure 6 This is a schematic diagram of the first and second annular partition structure of the present invention; Figure 7 This is a partial cross-sectional schematic diagram of the inner and outer cylinder sections of the present invention; Figure 8 This is a structural diagram of the pressure balancing membrane of the present invention; Figure 9 This is a structural diagram of the floating baffle travel variation of the present invention.

[0023] In the diagram: 1. Housing; 101. Fuel inlet; 102. Seawater pressure inlet; 2. Floating baffle; 21. First annular partition baffle; 211. Outer zone flow channel circulation chamber; 212. Middle annular zone; 213. Inner zone flow circulation chamber; 22. Second annular partition baffle; 23. Limiting ring block; 24. Air chamber; 3. Fuel chamber; 4. Compensation chamber; 5. Mounting flange; 6. Pressure balancing diaphragm; 61. Flexible pressure-resistant diaphragm; 7. Annular seal; 8. Air port A; 9. Air port B; 10. Air port C; 11. Sealing abutment ring; 111. Compression spring; 12. Outer cylinder section; 13. Annular air frame; 131. Pin; 132. Vent; 14. Conical spring; 15. Inner cylinder section; 16. Seawater filter; 17. Check valve. Detailed Implementation

[0024] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0025] This embodiment provides a temperature compensation expansion tank structure for an unmanned underwater vehicle's fuel system, including a tank body 1, a fuel inlet 101, and a seawater pressure inlet 102. The fuel inlet 101 is located on one side of the tank body 1, and the seawater pressure inlet 102 is located on the other end face of the tank body 1. The tank body 1 is a sealed pressure-resistant shell. A floating partition 2 is slidably fitted inside the tank body 1, dividing the interior of the tank body 1 into a fuel chamber 3 and a compensation chamber 4. The floating partition 2 is slidably and sealingly fitted with the inner wall of the tank body 1. A mounting bracket is provided near the seawater pressure inlet 102 on the tank body 1. A flange 5 is installed, and a pressure balancing membrane 6 is connected to the internal thread of the flange 5. The pressure balancing membrane 6 separates the interior of the housing 1 from the flow channel of the seawater pressure interface 102. One end of the flow channel of the seawater pressure interface 102 is connected to the outside of the pressure balancing membrane 6, and the other end is connected to the external seawater environment of the unmanned underwater vehicle. A seawater filter 16 is embedded in the flow channel of the seawater pressure interface 102. A one-way valve 17 is installed on the flow channel of the seawater pressure interface 102. The conduction direction of the one-way valve 17 is from the outside of the seawater pressure interface 102 to the outside of the pressure balancing membrane 6.

[0026] The temperature compensation expansion tank structure of this unmanned underwater vehicle (UUV) fuel system is installed between the fuel pipeline of the UUV and the external seawater pressure transmission pipeline. The fuel interface 101 is connected to the fuel pipeline or fuel storage chamber in the fuel system of the UUV, and the seawater pressure interface 102 is connected to the external seawater environment of the UUV. The tank body 1 is a sealed pressure-resistant shell. The floating baffle 2 is set inside the tank body 1 and can slide along the axial direction of the tank body 1. The floating baffle 2 and the inner wall of the tank body 1 form a sliding seal fit, thereby dividing the inside of the tank body 1 into a fuel chamber 3 and a compensation chamber 4 that are separated from each other.

[0027] The initial state after assembly is based on Figure 1 and Figure 3 The first annular partition plate 21 and the second annular partition plate 22 are arranged opposite to each other. The limiting ring block 23 is located between the first annular partition plate 21 and the second annular partition plate 22 to limit the relative distance between them. The annular seal 7 is installed in the gap between the limiting ring block 23 and the first annular partition plate 21 and the second annular partition plate 22.

[0028] The first annular partition plate 21, the second annular partition plate 22, and the limiting ring block 23 together constitute the main structure of the floating partition plate 2. An air cavity 24 is formed between the first annular partition plate 21 and the second annular partition plate 22. The outer flow channel circulation cavity 211, the middle annular region 212, and the inner flow circulation cavity 213 are connected to the air cavity 24 through air holes A8, B9, and C10, respectively. The sealing abutment ring 11 is connected to the middle of the inner wall of the second annular partition plate 22. The outer cylinder section 12 is coaxial with the sealing abutment ring 11. The annular air frame 13 is fitted onto the outer arc surface of the outer cylinder section 12 and is abutted against the sealing abutment ring 11 by a compression spring 111. The pin 131 is located in the middle of the inner wall of the annular air frame 13. The inner cylinder section 15 is connected to the pin 131 by a conical spring 14 and is located inside the outer cylinder section 12. Air channels are provided at the axial center of both the outer cylinder section 12 and the sealing abutment ring 11. A cavity communicating with the air channels is formed between the inner cylinder section 15 and the outer cylinder section 12. The vent 132 on the annular air frame 13 is connected to the air cavity 24.

[0029] The pressure balancing membrane 6 is installed inside the mounting flange 5 of the housing 1. The pressure balancing membrane 6 separates the interior of the housing 1 from the flow channel of the seawater pressure interface 102. The outer side of the pressure balancing membrane 6 is connected to the flow channel of the seawater pressure interface 102. A flexible pressure-resistant diaphragm 61 is connected to the front end of the inner arc face of the pressure balancing membrane 6. The seawater filter 16 and the one-way valve 17 are installed inside the flow channel of the seawater pressure interface 102. The conduction direction of the one-way valve 17 is from the outer side of the seawater pressure interface 102 to the outer side of the pressure balancing membrane 6.

[0030] The process of fuel entering and the change in fuel chamber volume is as follows: Figure 9 Fuel in the fuel system of the unmanned underwater vehicle enters the fuel chamber 3 through the fuel interface 101. Due to the sliding seal between the floating baffle 2 and the inner wall of the housing 1, the fuel entering the fuel chamber 3 is restricted to the fuel chamber 3. The fuel cannot directly enter the compensation chamber 4 through the mating part between the floating baffle 2 and the inner wall of the housing 1.

[0031] When the fuel temperature rises, the fuel volume increases. The fuel in the fuel chamber 3 exerts an axial force on the floating baffle 2 toward the compensation chamber 4. Under the action of this force, the floating baffle 2 moves along the inner wall of the housing 1 toward the compensation chamber 4. The volume of the fuel chamber 3 increases accordingly, and the volume of the compensation chamber 4 decreases accordingly. After the floating baffle 2 moves to the corresponding position, the pressure on both sides of the fuel chamber 3 and the compensation chamber 4 is in a new equilibrium state.

[0032] When the fuel temperature decreases, the fuel volume decreases accordingly, and the force on the side of the fuel chamber 3 changes. The gas pressure on the side of the compensation chamber 4, as well as the elastic resistance generated by the compression spring 111 and the conical spring 14, push the floating baffle 2 to move towards the side of the fuel chamber 3, so that the volume of the fuel chamber 3 is adjusted according to the change in fuel volume.

[0033] During the above process, the floating partition 2 moves along the axial direction of the housing 1 as a whole. The first annular partition 21, the second annular partition 22, the limiting ring block 23, the air chamber 24, and the flow channel structures set thereon move synchronously with the floating partition 2. The annular seal 7 moves synchronously with the floating partition 2 and maintains a sealed contact with the corresponding mating parts.

[0034] refer to Figure 2 and Figure 4 The gas flow in the compensation cavity 4 is divided into three zones: an outer zone flow channel circulation cavity 211, a middle ring region 212, and an inner zone flow circulation cavity 213, which are provided on the side of the first annular partition plate 21 toward the second annular partition plate 22. These regions are distributed along the radial direction of the first annular partition plate 21.

[0035] The outer zone circulation chamber 211 is connected to the air chamber 24 through vent A8, the middle ring region 212 is connected to the air chamber 24 through vent B9, and the inner zone circulation chamber 213 is connected to the air chamber 24 through vent C10. Therefore, the gas in the compensation chamber 4 can enter the air chamber 24 and flow between the outer zone circulation chamber 211, the middle ring region 212, and the inner zone circulation chamber 213 through vents A8, B9, and C10 respectively. When the floating baffle 2 moves to the side of the compensation chamber 4, the effective volume of the compensation chamber 4 decreases, and the gas in the compensation chamber 4 enters the air chamber 24 and each zone flow channel. The gas can be redistributed through vents A8, B9, and C10 according to the pressure difference of each zone.

[0036] When the floating baffle 2 moves toward the fuel chamber 3, the effective volume of the compensation chamber 4 increases, and the gas in the gas chamber 24 and the flow channels of each zone is replenished to the compensation chamber 4. Through the above gas flow, the gas volume of each region inside the gas chamber 24 is adjusted accordingly as the floating baffle 2 moves.

[0037] at the same time Figure 5 and Figure 7 The outer cylinder section 12 abuts against the sealing abutment ring 11 via a compression spring 111. When the gas pressure inside the gas chamber 24 or the relative position of the floating baffle 2 changes, the outer cylinder section 12 can move axially relative to the sealing abutment ring 11. When the outer cylinder section 12 moves, the compression spring 111 is compressed or rebounds. The compression spring 111 applies an elastic force to the outer cylinder section 12 in the opposite direction to its displacement. The inner cylinder section 15 is located inside the outer cylinder section 12 and is connected to the pin 131 on the inner wall of the annular gas frame 13 via a conical spring 14. When the inner cylinder section 15 undergoes axial displacement relative to the outer cylinder section 12, the conical spring 14 is compressed or elongated and applies an elastic restoring force to the inner cylinder section 15. A gas flow cavity is formed between the outer arc surface of the inner cylinder section 15 and the inner arc surface of the outer cylinder section 12. This cavity is connected to the gas passages on the outer cylinder section 12 and the sealing abutment ring 11.

[0038] The gas in the compensation chamber 4 can enter the communication area between the annular gas frame 13 and the outer cylinder section 12 through the vent 132 on the annular gas frame 13, and then flow into the corresponding gas zone through the gas passage on the outer cylinder section 12 and the sealing abutment ring 11. The gas can also flow in the opposite direction. The coaxial fit between the outer cylinder section 12 and the sealing abutment ring 11, and the sleeve fit between the inner cylinder section 15 and the outer cylinder section 12, limit the relative position of the above gas passages.

[0039] When the outer cylinder section 12 or the inner cylinder section 15 moves axially, the compression spring 111 and the conical spring 14 undergo elastic deformation. When the external force acting on the corresponding cylinder section decreases, the compression spring 111 and the conical spring 14 push the outer cylinder section 12 and the inner cylinder section 15 to move to their original positions. The outer cylinder section 12, the inner cylinder section 15 and the related air passages maintain an axial fit relationship under the action of the elastic elements.

[0040] according to Figure 8 The process of transmitting external seawater pressure: During the descent of the unmanned underwater vehicle, external seawater enters the pressure transmission channel through the seawater pressure interface 102. The seawater first passes through the seawater filter 16, which is set in the channel of the seawater pressure interface 102 to filter the seawater entering the channel. The filtered seawater continues to flow along the channel to the outside of the pressure balance membrane 6.

[0041] When the external seawater pressure increases, the one-way valve 17 opens or remains open in its conduction direction. Seawater flows from the outside of the seawater pressure interface 102 to the outside of the pressure balancing membrane 6, causing the outside of the pressure balancing membrane 6 to bear the corresponding seawater pressure. When the seawater tends to flow in the opposite direction from the outside of the pressure balancing membrane 6 to the outside of the seawater pressure interface 102, the one-way valve 17 blocks or restricts this reverse flow. The pressure balancing membrane 6 separates the flow channel of the seawater pressure interface 102 from the inside of the housing 1, so that the seawater does not directly enter the inside of the housing 1. After the seawater pressure acts on the outside of the pressure balancing membrane 6, the pressure balancing membrane 6 undergoes corresponding stress deformation, which drives the flexible pressure-resistant diaphragm 61 at the front end of its inner arc to displace or deform. The flexible pressure-resistant diaphragm 61 is located on one side inside the housing 1. Its deformation changes the stress state of the pressure balancing membrane 6 and the opposite side inside the housing 1, and transmits the external seawater pressure to the compensation chamber 4 in the form of diaphragm displacement and gas pressure change.

[0042] When the external seawater pressure decreases, the pressure on the pressure balancing membrane 6 and the flexible pressure-resistant diaphragm 61 decreases. The diaphragm structure undergoes reverse displacement under its own elasticity or the pressure difference between the two sides. Since the conduction direction of the one-way valve 17 is limited to the outside of the seawater pressure interface 102 to the outside of the pressure balancing membrane 6, the seawater in the flow channel outside the pressure balancing membrane 6 is not discharged through the one-way valve 17 in the opposite direction. The displacement state of the pressure balancing membrane 6 and the flexible pressure-resistant diaphragm 61 is readjusted according to the seawater pressure in the flow channel and the pressure on the side of the compensation cavity 4 inside the tank 1.

[0043] When the stress state of the pressure balancing diaphragm 6 and the flexible pressure-resistant diaphragm 61 changes, the gas pressure on one side of the compensation chamber 4 changes accordingly. After a pressure difference is formed between the fuel chamber 3 and the compensation chamber 4, the floating baffle 2 moves axially along the inner wall of the housing 1.

[0044] When the floating baffle 2 moves toward the compensation chamber 4, the volume of the fuel chamber 3 increases accordingly, and the effective volume of the compensation chamber 4 decreases accordingly. The movement state of the floating baffle 2 is determined by the fuel pressure on the fuel chamber 3 side, the gas pressure on the compensation chamber 4 side, and the elastic resistance of the compression spring 111 and the conical spring 14.

[0045] During the movement of the floating baffle 2, the air chamber 24 moves synchronously with the floating baffle 2. The gas in the compensation chamber 4 flows through the air holes A8, B9, C10, vent 132, and the air passages on the outer cylinder section 12 and the sealing abutment ring 11. The outer cylinder section 12 and the inner cylinder section 15 undergo axial displacement and reset under the elastic action of the compression spring 111 and the conical spring 14, respectively, so that the various gas flow parts maintain mutual cooperation.

[0046] Working process when temperature change and seawater pressure change occur simultaneously: When the unmanned underwater vehicle is running underwater, fuel temperature change and external seawater pressure change may occur simultaneously. When the fuel temperature rises, the fuel volume in the fuel chamber 3 increases, pushing the floating baffle 2 to move towards the compensation chamber 4. When the external seawater pressure rises, seawater enters the outside of the pressure balance membrane 6 through the seawater pressure interface 102, the seawater filter 16 and the one-way valve 17. The pressure balance membrane 6 and the flexible pressure-resistant diaphragm 61 undergo corresponding force changes, which causes the gas pressure in the compensation chamber 4 to change.

[0047] When the fuel temperature decreases or the external seawater pressure decreases, the pressure relationship between the fuel chamber 3 and the compensation chamber 4 changes in the opposite direction. The floating baffle 2 moves towards the fuel chamber 3, and the compression spring 111 and the conical spring 14 apply elastic restoring force to the outer cylinder section 12 and the inner cylinder section 15 at the corresponding positions.

[0048] Therefore, under the combined effect of temperature changes and external seawater pressure changes, the volume of the fuel chamber 3 is adjusted by the axial displacement of the floating baffle 2, the gas in the compensation chamber 4 is redistributed through multiple vents and air channels, the pressure balancing membrane 6 and the flexible pressure-resistant diaphragm 61 transmit force between the seawater pressure interface 102 and the inside of the housing 1, and the seawater filter 16 and the one-way valve 17 filter the seawater entering the pressure channel and limit the direction of seawater flow.

Claims

1. A temperature-compensated expansion tank structure for an unmanned underwater vehicle fuel system, comprising a tank body (1), a fuel inlet (101), and a seawater pressure inlet (102), wherein the fuel inlet (101) is disposed on one side of the tank body (1), and the seawater pressure inlet (102) is disposed on the other end face of the tank body (1), characterized in that: The housing (1) is a sealed pressure-resistant shell. A floating partition (2) is slidably sleeved inside the housing (1). The floating partition (2) divides the inside of the housing (1) into a fuel chamber (3) and a compensation chamber (4). The floating partition (2) is slidably sealed with the inner wall of the housing (1). The housing (1) is provided with a mounting flange (5) near the seawater pressure interface (102). The mounting flange (5) is internally threaded with a pressure balancing membrane (6). The pressure balancing membrane (6) separates the interior of the housing (1) from the flow channel of the seawater pressure interface (102). One end of the flow channel of the seawater pressure interface (102) is connected to the outside of the pressure balancing membrane (6), and the other end is connected to the seawater environment outside the unmanned underwater vehicle. The seawater pressure interface (102) is fitted with a seawater filter (16) in its flow channel. A one-way valve (17) is provided on the flow channel of the seawater pressure interface (102). The one-way valve (17) is directed from the outside of the seawater pressure interface (102) to the outside of the pressure balance membrane (6).

2. The structure of the temperature-compensated expansion tank for the fuel system of an unmanned underwater vehicle according to claim 1, characterized in that, The floating partition (2) includes a first annular partition (21) and a second annular partition (22). The first annular partition (21) and the second annular partition (22) are arranged opposite to each other, and a limiting ring block (23) is provided between them. An annular seal (7) is provided in the gap between the limiting ring block (23) and the first annular partition (21) and the second annular partition (22).

3. The structure of a temperature-compensated expansion tank for an unmanned underwater vehicle fuel system according to claim 2, characterized in that, The first annular partition (21) has an outer flow channel circulation cavity (211) at one edge facing the second annular partition (22), and an air hole A (8) is provided at the bottom of one end of the outer flow channel circulation cavity (211).

4. The structure of a temperature-compensated expansion tank for an unmanned underwater vehicle fuel system according to claim 3, characterized in that, The first annular partition plate (21) has a middle ring area (212) in the middle of the side facing the second annular partition plate (22), and the middle ring area (212) has an air hole B (9).

5. The structure of a temperature-compensated expansion tank for an unmanned underwater vehicle fuel system according to claim 4, characterized in that, The first annular partition (21) has an inner circulation cavity (213) at the center of the side facing the second annular partition (22). The bottom end face of the inner circulation cavity (213) has an air hole C (10). An air cavity (24) is formed between the first annular partition (21) and the second annular partition (22). The air holes A (8), B (9) and C (10) are all connected to the air cavity (24).

6. The structure of a temperature-compensated expansion tank for an unmanned underwater vehicle fuel system according to claim 5, characterized in that, A sealing abutment ring (11) is connected to the middle of the inner wall of the second annular partition plate (22). The second annular partition plate (22) is provided with a through hole coaxial with the sealing abutment ring (11). A compression spring (111) is connected to one side of the outer arc surface of the sealing abutment ring (11). The other end of the compression spring (111) is connected to an outer cylinder section (12). The outer cylinder section (12) is coaxial with the sealing abutment ring (11).

7. The structure of a temperature-compensated expansion tank for an unmanned underwater vehicle fuel system according to claim 6, characterized in that, The outer cylinder section (12) abuts against the sealing abutment ring (11) by a compression spring (111). Both the outer cylinder section (12) and the sealing abutment ring (11) are provided with air channels at their axial centers. The outer arc surface of the outer cylinder section (12) is fitted with an annular air frame (13).

8. The structure of a temperature-compensated expansion tank for a fuel system of an unmanned underwater vehicle according to claim 7, characterized in that, The annular air frame (13) has a pin (131) in the middle of its inner wall. The outer arc surface of the pin (131) is connected to a conical spring (14). The other end of the conical spring (14) is connected to an inner cylinder section (15). The outer arc surface of the inner cylinder section (15) and the inner arc surface of the outer cylinder section (12) form a cavity that communicates with the air passage.

9. The structure of a temperature-compensated expansion tank for an unmanned underwater vehicle fuel system according to claim 8, characterized in that, The annular air frame (13) has an air vent (132) on one side of its outer arc surface. The air vent (132) is connected to the air cavity (24) and corresponds to the air hole A (8), air hole B (9) and air hole C (10).

10. The structure of a temperature-compensated expansion tank for a fuel system of an unmanned underwater vehicle according to claim 1, characterized in that, The inner arc front end of the pressure balancing membrane (6) is connected to a flexible pressure-resistant diaphragm (61), which is located on the side opposite to the inside of the pressure balancing membrane (6) and the tank (1). The flow channel of the seawater pressure interface (102) is connected to the outside of the pressure balancing membrane (6).

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