A three-way valve based on mechanical anti-backflow self-locking mechanism

Abstract

The application discloses a three-way valve based on a mechanical anti-backflow self-locking mechanism and belongs to the technical field of fluid pipeline control. The valve mainly comprises a valve body and an anti-backflow self-locking mechanism independently arranged in the anti-backflow self-locking mechanism bin of an auxiliary road flow channel. The anti-backflow self-locking mechanism comprises a containing space formed by a mechanism base and a mechanism cover, a low-density float arranged in the containing space, an L-shaped float connecting rod, a plug cover connecting rod with a sliding rail and a plug cover hinged through the plug cover connecting rod. The float is driven by the float sinking and floating, and the transmission of the roller and the sliding rail is achieved. In addition, the force of the fluid in the auxiliary road and the main road on the plug cover is added. The opening and closing of the plug cover and the dead point self-locking are automatically controlled. When the auxiliary road has oil, the plug cover is automatically opened and locked. When the auxiliary road has no oil, the plug cover is automatically closed tightly. The backflow of the fluid in the main road and the total road to the auxiliary road is prevented, and the aircraft center of gravity is not affected. The application is a pure mechanical structure, has high reliability, is easy to maintain and is suitable for the unmanned aerial vehicle oil supply system with high requirements for the center of gravity balance and reliability.

Description

Technical Field

[0001] This invention belongs to the field of fluid pipeline control technology, specifically relating to a three-way valve based on a mechanical anti-backflow self-locking mechanism. Background Technology

[0002] In UAV fluid systems, a main fuel tank and multiple auxiliary fuel tanks are typically installed to ensure fuel supply safety. To guarantee system reliability, the backup auxiliary lines must be readily energized or deactivated when the main line is functioning normally. Furthermore, when the main line is operating alone, backflow of fluid to the backup auxiliary lines must be prevented, avoiding energy waste, system efficiency degradation, and, most importantly, the safety hazard of center of gravity shift. Current fuel line switching and backflow prevention mechanisms largely rely on electric valves, solenoid valves, or manual valves, depending on a stable power supply and control system. This approach is costly, prone to failure under complex operating conditions, structurally complex, has low reliability, and requires high structural quality.

[0003] Current valve technologies do not address the specific technical issues of preventing fluid backflow from affecting the aircraft's center of gravity balance, nor have they disclosed a purely mechanical anti-backflow self-locking valve that can achieve "self-opening when oil is available, self-locking at the specified point; rapid closing when oil is unavailable, preventing backflow".

[0004] Therefore, the industry urgently needs a purely mechanical anti-backflow device that can autonomously sense the status of auxiliary oil flow, achieve reliable opening and closing and self-locking, and realize intelligent oil circuit management to simplify system architecture, improve inherent reliability and reduce overall weight. Summary of the Invention

[0005] The technical problem to be solved: To overcome the shortcomings of existing technologies, this invention provides a three-way valve based on a mechanical anti-backflow self-locking mechanism. It utilizes the auxiliary oil flow to drive a float, which, through a connecting rod and slide rail, opens the plug and self-locks past the dead point. At this point, the main flow impact force reverses to become the internal force maintaining valve opening. When the auxiliary oil flow is cut off, the float sinks, the mechanism retracts to the dead point, and the plug closes tightly under the pressure of the main flow, preventing backflow from affecting the drone's center of gravity. This invention aims to automatically achieve intelligent control logic in a purely mechanical manner: "automatic opening when oil is available, self-locking past the dead point; rapid closing when oil is unavailable, preventing backflow." This solves the problems of existing systems relying on external energy, complex structure, limited functionality, and poor reliability, effectively preventing fuel backflow and possessing high reliability and parallel scalability.

[0006] The technical solution of this invention is: a three-way valve based on a mechanical anti-backflow self-locking mechanism, comprising: Valve body 1 is provided with main line interface 1-1, auxiliary line interface 1-5, main line interface 1-2 and drain port interface 1-3. The main line interface 1-1 and auxiliary line interface 1-5 converge in the valve body 1 and flow into the main line interface 1-2. The drain port interface 1-3 is located downstream of the convergence point. A backflow prevention self-locking mechanism is installed in the auxiliary channel between the auxiliary channel interface 1-5 and the junction point, including a plug 8 and a float 5. The float 5 is installed in the auxiliary channel and moves under the action of the fluid in the auxiliary channel, thereby driving the transmission mechanism to open the plug 8. The transmission mechanism has a dead point position. When the plug 8 is opened and passes the dead point position, the transmission mechanism enters a self-locking state. At this time, the fluid impact force from the main channel interface 1-1 acts on the closing direction of the plug 8, but this closing force is converted into a self-locking internal force to maintain the open state of the plug 8 through the transmission mechanism. When there is no fluid flowing in the auxiliary channel, the float 5 resets and drives the plug 8 to return past the dead point position through the transmission mechanism. The plug 8 closes under the action of the fluid impact force from the main channel interface 1-1, thereby preventing the fluid from flowing back from the main channel interface 1-1 and / or the main channel interface 1-2 to the auxiliary channel interface 1-5. A further technical solution of the present invention is: the anti-backflow self-locking mechanism further includes a mechanism base 2 and a mechanism cover 3, the mechanism base 2 and the mechanism cover 3 together form an accommodating space, and the float 5 is disposed in the accommodating space; The transmission mechanism includes a float connecting rod 4 and a plug connecting rod 6. The float 5 is fixedly connected to one end of the float connecting rod 4, and the plug 8 is fixedly connected to one end of the plug connecting rod 6. The other ends of the float connecting rod 4 and the plug connecting rod 6 are connected by a roller 7.

[0007] A further technical solution of the present invention is: the width of the mechanism seat 2 is smaller than the diameter of the auxiliary flow channel, and the end facing the auxiliary interface 1-5 has a flow guiding structure. The flow guiding structure includes an acute-angled leading edge 2-1 located at the upper part and a trumpet-shaped inlet 2-2 located at the lower part. The large end of the trumpet-shaped inlet 2-2 faces the auxiliary interface 1-5 and is used to introduce the auxiliary flow into the interior of the mechanism seat 2. The mechanism seat 2 includes a main plane 2-4 with an approximate fan-shaped profile. The inner arc of the main plane 2-4 extends towards the center to form a secondary plane 2-5. The two radial sides of the fan-shaped main plane 2-4 serve as limits on the travel of the float 5. The secondary plane 2-5 is provided with a main shaft 2-6 and a secondary shaft 2-7. The float connecting rod 4 is hinged to the main shaft 2-6, and the plug connecting rod 6 is hinged to the secondary shaft 2-7. The float connecting rod 4 and the plug connecting rod 6 swing within the space of the secondary plane 2-5.

[0008] A further technical solution of the present invention is as follows: the float connecting rod 4 is an L-shape composed of a long arm 4-1 and a short arm 4-2, with an obtuse angle between the two arms, and the float 5 is fixedly connected to the end of the long arm 4-1; the float connecting rod 4 has a float connecting rod hinge hole 4-3 at the intersection of the long arm 4-1 and the short arm 4-2, and is rotatably connected to the main shaft 2-6 of the secondary plane of the mechanism seat 2 through the float connecting rod hinge hole 4-3; The plug connecting rod 6 has a slide rail 6-1 and a U-shaped short arm 6-2. A plug connecting rod hinge hole 6-3 is provided at the intersection of the two. The plug connecting rod is rotatably connected to the secondary shaft 2-7 of the secondary plane of the mechanism seat 2 through the plug connecting rod hinge hole 6-3. The plug 8 is fixedly connected to the end of the U-shaped short arm 6-2. The roller 7 is mounted on the roller mounting hole 4-4 at the end of the short arm 4-2 and rolls in contact with the slide rail 6-1.

[0009] A further technical solution of the present invention is: the roller 7 is dumbbell-shaped, including a roller connecting shaft 7-1 in the middle and two wheel disks 7-2 on both sides. The roller connecting shaft 7-1 passes through the roller mounting hole 4-4, and the two wheel disks 7-2 on both sides roll in contact with the surface of the slide rail 6-1 respectively. The slide rail 6-1 has a raised structure in the middle of the track to prevent the two wheel disks 7-2 from derailing.

[0010] A further technical solution of the present invention is: the included angle α between the short arm 4-2 of the float connecting rod 4 and the slide rail 6-1 of the plug connecting rod 6 is an obtuse angle when the plug 8 is closed and an acute angle when the plug 8 is open; the included angle α is equal to 90° at the dead point position.

[0011] A further technical solution of the present invention is: the density of the float 5 is less than the density of the fluid. When fluid flows through the auxiliary channel, it floats up under the action of buoyancy, thereby driving the float connecting rod 4 to rotate; when no fluid flows through the auxiliary channel, the float 5 sinks under the action of gravity, thereby driving the float connecting rod 4 to rotate in the opposite direction.

[0012] A further technical solution of the present invention is as follows: the auxiliary flow channel of the valve body 1 is provided with an anti-backflow self-locking mechanism bracket 1-6 and an anti-backflow self-locking mechanism base 1-7; the anti-backflow self-locking mechanism bracket 1-6 is an inclined structure, set at an angle with the incoming flow direction, and its width is 1 / 5 of the diameter of the auxiliary flow channel, so as to divert the incoming flow part to the area where the float 5 is located; the anti-backflow self-locking mechanism base 1-7 is welded to the anti-backflow self-locking mechanism bracket 1-6 and is used to install the mechanism seat 2.

[0013] A further technical solution of the present invention is: the oil drain port includes an oil drain port seat 10 and an oil drain port nut 11. The upper end of the oil drain port seat 10 is installed on the oil drain port interface 1-3 through the internal thread 10-1 of the oil drain port seat. The lower end of the oil drain port seat 10 is provided with an external thread 10-2 of the oil drain port seat. The oil drain port nut 11 is screwed onto the external thread 10-2 of the oil drain port seat. When the oil drain port nut 11 is unscrewed, the oil drain port is open to discharge fluid or impurities.

[0014] A backflow prevention control method for a three-way valve based on a mechanical backflow prevention self-locking mechanism includes the following steps: Self-locking opening procedure during auxiliary pipeline oil supply: When the auxiliary pipeline pump starts supplying oil, the fluid enters the auxiliary pipeline flow channel through the auxiliary pipeline interface 1-5. Part of the fluid directly impacts the plug 8 to generate an opening torque, while the other part of the fluid is diverted to the area where the float 5 is located, causing the float 5 to float. The buoyancy of the float 5 is transmitted through the transmission mechanism and assists in driving the plug 8 to open. When the transmission mechanism moves past the dead point position, it enters the self-locking state. The fluid impact force from the main pipeline is converted into a self-locking internal force that maintains the open state of the plug 8 through the transmission mechanism, keeping the plug 8 fully open. Backflow prevention shutdown procedure when auxiliary line oil supply is interrupted: When the auxiliary line pump is shut down and the auxiliary line oil supply is interrupted, the fluid in the area where the float 5 is located decreases, and the float 5 sinks under the action of gravity. Through the transmission mechanism, it drives the plug 8 to retract past the dead point position and release the self-locking state; the plug 8 closes quickly under the action of the fluid impact force from the main line and fits tightly with the plug sealing ring 9 to prevent the fluid from the main line and the main line from flowing back to the auxiliary line.

[0015] Beneficial effects The beneficial effects of this invention are as follows: This invention transforms the dead point from a "rapid-action trigger point" to a "continuous self-locking working point." Through float-connecting rod-slide rail transmission, when there is oil in the auxiliary circuit, the plug self-locks past the dead point, and the impact force in the main circuit reverses into the valve opening internal force; when the auxiliary circuit is cut off from oil, the float sinks to unlock, and the pressure in the main circuit automatically tightens the closed cap. This achieves purely mechanical, zero-energy anti-backflow control, effectively ensuring the balance of the UAV's center of gravity. Specific effects are analyzed below: 1. This invention realizes the intelligent autonomous control logic of the auxiliary road "automatic opening when there is oil and automatic locking when passing the point; fast closing when there is no oil and prevention of backflow". It does not rely on external energy, has a simple structure, low cost and high reliability. It fundamentally eliminates the inherent fault modes of the electronic control system and can still work reliably in extreme environments, realizing true zero-energy automation.

[0016] 2. The lever-slide rail dead-point self-locking mechanism of this invention can convert the impact force of the main oil flow into the internal force to maintain the valve open state after the backup circuit is opened, ensuring absolute stability during parallel oil supply and completely avoiding valve vibration or accidental closure caused by pressure pulsation, which is something that traditional check valves or simple mechanical valves cannot achieve.

[0017] 3. The accommodating space formed by the mechanism seat and the mechanism cover of the present invention forms a fluid buffer chamber. This buffer chamber has a hysteresis sensing characteristic for changes in oil level in the auxiliary flow channel: when the oil level rises, it needs to reach the highest point of the mechanism seat before a large amount of fluid can be filled into the buffer chamber to drive the float to float completely; when the oil level falls, the fluid in the buffer chamber needs to gradually flow out before the float gradually sinks. The hysteresis characteristic makes the anti-backflow self-locking mechanism insensitive to short-term pulsations and pressure fluctuations in the auxiliary flow, preventing the cover from frequently opening and closing due to flow fluctuations and improving system stability.

[0018] After the auxiliary fuel supply stops, the anti-backflow self-locking mechanism immediately closes, preventing fuel from flowing back into the auxiliary fuel tank due to pressure difference or siphon effect. This is especially important for a platform that is extremely sensitive to changes in the center of gravity of the drone.

[0019] 4. The valve body of this invention can be configured with any number of auxiliary line interfaces according to the number of auxiliary oil tanks. Each auxiliary line is independently equipped with an anti-backflow self-locking mechanism. Each line works independently and does not interfere with each other, which has excellent engineering adaptability.

[0020] 5. The present invention has a thickened main flow channel, which allows the fuel after the main road and multiple auxiliary roads merge to flow smoothly to the fuel-using equipment, and will not affect the overall fuel supply efficiency due to the local flow resistance of the plugging mechanism.

[0021] 6. The entire mechanism of this invention is integrated inside the valve body, with no exposed moving parts, making it impact-resistant and contamination-resistant. The drain port design facilitates manual removal of impurities from the pipeline during ground maintenance, and the parts of the anti-backflow locking mechanism can also be disassembled and replaced through the drain port. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of a backflow prevention self-locking mechanical three-way valve according to an embodiment of the present invention; (a) isometric view, (b) left view; Figure 2 This is a cross-sectional view of the overall structure of a backflow prevention self-locking mechanical three-way valve according to an embodiment of the present invention; (a) schematic diagram of the backflow prevention self-control mechanism and the drain port; (b) backflow prevention self-control mechanism; Figure 3 This is a schematic diagram of the working principle of the anti-backflow mechanism in an embodiment of the present invention; (a) plug closed state, (b) dead point state, (c) plug open state; Figure 4 This is a schematic diagram of the valve body 1 structure in an embodiment of the present invention; Figure 5 This is a schematic diagram of the mechanism base 2 in an embodiment of the present invention; Figure 6 This is a schematic diagram of the mechanism cover 3 in an embodiment of the present invention; Figure 7 This is a schematic diagram of the float connecting rod 4 in an embodiment of the present invention; Figure 8 This is a schematic diagram of the float 5 structure in an embodiment of the present invention; Figure 9 This is a schematic diagram of the plug connecting rod 6 in an embodiment of the present invention; Figure 10 This is a schematic diagram of the roller 7 structure in an embodiment of the present invention; Figure 11 This is a schematic diagram of the plug 8 structure in an embodiment of the present invention; Figure 12This is a schematic diagram of the sealing ring 9 in an embodiment of the present invention; Figure 13 This is a schematic diagram of the oil drain port seat 10 in an embodiment of the present invention; Figure 14 This is a schematic diagram of the oil drain nut 11 in an embodiment of the present invention.

[0023] Explanation of reference numerals in the attached diagram: 1. Valve body; 1-1. Main line interface; 1-2. Main line interface; 1-3. Drain port interface; 1-4. Anti-backflow self-locking mechanism compartment; 1-5. Auxiliary line interface; 1-6. Anti-backflow self-locking mechanism bracket; 1-7. Anti-backflow self-locking mechanism base; 1-8. Mounting groove; 1-9. Mounting plate; 2. Mechanism seat; 2-1. Front edge of mechanism seat; 2-2. Mechanism seat inlet; 2-3. Mechanism seat mounting plate; 2-4. Main plane of mechanism seat; 2-5. Secondary plane of mechanism seat; 2-6. Main shaft of secondary plane of mechanism seat; 2-7. Secondary shaft of secondary plane of mechanism seat; 2-8. Rear edge of mechanism seat; 3. Mechanism cover; 3-1. 3-1. Mechanism cover inlet; 3-2. Mechanism cover main plane; 3-3. Mechanism cover secondary plane; 3-4. Mechanism cover rear edge; 3-5. Mechanism cover mounting plate; 4. Float connecting rod; 4-1. Long arm; 4-2. Short arm; 4-3. Float connecting rod hinge hole; 4-4. Roller mounting hole; 5. Float; 6. Plug connecting rod; 6-1. Slide rail; 6-2. U-shaped short arm; 6-3. Plug connecting rod hinge hole; 7. Roller; 7-1. Roller connecting shaft; 7-2. Wheels on both sides; 8. Plug; 9. Plug sealing ring; 10. Oil drain port seat; 10-1. Oil drain port seat internal thread; 10-2. Oil drain port seat external thread; 11. Oil drain port nut. Detailed Implementation The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the invention, and should not be construed as limiting the invention.

[0024] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0025] To address the problems existing in the prior art, this invention proposes a three-way valve based on a mechanical anti-backflow self-locking mechanism, comprising: Valve body 1 is provided with main line interface 1-1, auxiliary line interface 1-5, main line interface 1-2 and drain port interface 1-3. The main line interface 1-1 and auxiliary line interface 1-5 converge in the valve body 1 and flow into the main line interface 1-2. The drain port interface 1-3 is located downstream of the convergence point. A backflow prevention self-locking mechanism is installed in the auxiliary channel between the auxiliary channel interface 1-5 and the junction point, including a plug 8 and a float 5. The float 5 is installed in the auxiliary channel and moves under the action of the fluid in the auxiliary channel, thereby driving the transmission mechanism to open the plug 8. The transmission mechanism has a dead point position. When the plug 8 is opened and passes the dead point position, the transmission mechanism enters a self-locking state. At this time, the fluid impact force from the main channel interface 1-1 acts on the closing direction of the plug 8, but this closing force is converted into a self-locking internal force to maintain the open state of the plug 8 through the transmission mechanism. When there is no fluid flowing in the auxiliary channel, the float 5 resets and drives the plug 8 to return past the dead point position through the transmission mechanism. The plug 8 closes under the action of the fluid impact force from the main channel interface 1-1, thereby preventing the fluid from flowing back from the main channel interface 1-1 and / or the main channel interface 1-2 to the auxiliary channel interface 1-5.

[0026] The above technical solution will be further analyzed below with reference to the accompanying drawings and examples: In one embodiment, refer to Figure 1 and Figure 2 As shown, a backflow prevention self-locking mechanical three-way valve mainly consists of three parts: valve body, backflow prevention self-control mechanism, and oil drain port.

[0027] Define the direction of the flow from the auxiliary road as the positive x-direction, and the opposite direction of the flow from the main road as the positive y-direction. The positive z-direction is then deduced using the right-hand rule.

[0028] Reference Figure 3 As shown, valve body 1 is the main supporting structure of the three-way valve. It is formed by the perpendicular intersection of two horizontal and vertical pipes of the same diameter and wall thickness in the same plane, creating a three-way confluence structure (left, top, and bottom). Since the main line is the confluence of the auxiliary and main lines, and is located near the area with high flow resistance at plug 8, the main line diameter is set larger to accommodate a larger flow rate and reduce flow resistance. Main line interface 1-1, main line interface 1-2, and drain port interface 1-3 are all externally threaded for connecting to other pipes. The auxiliary line consists of the anti-backflow self-locking mechanism chamber 1-4 and auxiliary line interface 1-5. Auxiliary line interface 1-5 is also externally threaded for connecting to other pipes.

[0029] The diameter of the main flow channel corresponding to the main flow interface 1-2 is greater than the diameter of the main flow channel corresponding to the main flow interface 1-1 and the diameter of the auxiliary flow channel corresponding to the auxiliary flow interface 1-5, so as to reduce the flow resistance after the main flow and auxiliary flow merge and ensure that the merging fluid flows smoothly to the oil-using equipment.

[0030] Furthermore, the valve body 1 is provided with two or more auxiliary ports 1-5, and each auxiliary port 1-5 is independently equipped with an anti-backflow self-locking mechanism in the auxiliary flow channel between the junction point and the auxiliary port 8. Each anti-backflow self-locking mechanism independently senses the fluid state of the corresponding auxiliary port and independently controls the opening and closing of the corresponding plug 8. The auxiliary ports do not interfere with each other, realizing independent control and anti-backflow protection of parallel oil supply of multiple auxiliary ports.

[0031] The anti-backflow self-locking mechanism compartment 1-4 is a section of pipe with a slightly larger diameter, used to house the anti-backflow self-locking mechanism. Within the anti-backflow self-locking mechanism compartment 1-4, facing the direction of the auxiliary flow, an anti-backflow self-locking mechanism support 1-6 is installed. This support is an inclined structure, its width approximately 1 / 5 of the diameter of the anti-backflow self-locking mechanism compartment 1-4, forming a certain angle with the flow direction. This allows the incoming flow to generate an upward diversion trend when impacting the anti-backflow self-locking mechanism support 1-6, thus dividing the auxiliary flow into a main flow and a secondary flow. The main flow directly impacts the plug 8, generating an opening torque, while the secondary flow is guided through the trumpet-shaped inlet 2-2 into the area where the float 5 is located, forming a dual drive for opening the plug 8. Simultaneously, due to its narrow width, the pressure loss on the auxiliary flow is minimal. An anti-backflow self-locking mechanism base 1-7 is welded onto the anti-backflow self-locking mechanism support 1-6. Its main body consists of two L-shaped pieces, each with an obtuse angle, arranged opposite each other. Facing the direction of the incoming flow from the auxiliary channel, the width of the initial part of the anti-backflow self-locking mechanism base 1-7 is the same as the width of the anti-backflow self-locking mechanism bracket 1-6; along the flow direction, its width gradually narrows, and after a short distance, the width remains unchanged, while the height gradually narrows but the upper edge always remains horizontal. The front edge of the L-shaped plate is also provided with a mounting groove 1-8, and the rear edge is provided with a mounting plate 1-9 perpendicular to the direction of the incoming flow.

[0032] The oil drain port interface 1-3 is located downstream of the confluence point and directly faces the anti-backflow self-locking mechanism compartment 1-4. The opening formed after removing the oil drain port seat 10 also serves as a maintenance channel, which is used to disassemble, inspect and replace the components of the anti-backflow self-locking mechanism during ground maintenance, so as to realize the reuse of sewage discharge and maintenance channel.

[0033] The anti-backflow self-control mechanism is the core part of realizing the anti-backflow self-locking function. It consists of mechanism base 2, mechanism cover 3, float connecting rod 4, float 5, plug connecting rod 6, roller 7, plug 8, and plug sealing ring 9.

[0034] Reference Figure 5As shown, the mechanism seat 2 is the main support structure of the anti-backflow self-locking mechanism, and its front-to-back width is approximately 1 / 10 of the diameter of the anti-backflow self-locking mechanism chamber 1-4. Its upper part facing the incoming flow has an acute angle, defined as the leading edge 2-1 of the mechanism seat. The lower part facing the incoming flow is flared, defined as the inlet 2-2 of the mechanism seat, with the larger opening facing the incoming flow. The lower shape of the inlet 2-2 is adapted to the self-locking mechanism bracket 1-6, and a mechanism seat mounting plate 2-3 is provided for installation in conjunction with the mounting groove 1-8. The mechanism seat 2 mainly consists of two xy planes: the main plane 2-4 and the secondary plane 2-5. The distance between the secondary plane 2-5 and the z=0 plane is slightly smaller than that of the main plane 2-4. The secondary plane 2-5 has a main axis 2-6 and a secondary axis 2-7. In addition, a trailing edge 2-8 is also provided.

[0035] Furthermore, the flow guiding structure of the mechanism seat 2 facing the auxiliary channel interface 1-5 is designed with an asymmetrical upper and lower part: the acute-angled leading edge 2-1 at the top is used to reduce the frontal impact resistance of the incoming flow on the mechanism seat 2; the large end of the trumpet-shaped inlet 2-2 at the bottom faces the direction of the incoming flow and is used to actively capture and guide the secondary flow of the auxiliary channel into the area where the float 5 is located; the upper and lower parts work together to reduce the flow resistance while ensuring that the float 5 obtains sufficient driving flow.

[0036] Reference Figure 6 As shown, the mechanism cover 3 is the cover plate of the mechanism seat 2, and is provided with mechanism cover inlet 3-1, mechanism cover main plane 3-2, mechanism cover secondary plane 3-3, mechanism cover rear edge 3-4 and mechanism cover mounting plate 3-5. The structure of each part has a certain symmetry with the mechanism seat 2 and the functions correspond to each other.

[0037] Reference Figure 7 As shown, the float connecting rod 4 is the main force transmission structure of the anti-backflow self-control mechanism. It is L-shaped, with an obtuse angle between its long arm 4-1 and short arm 4-2. The intersection of the long arm 4-1 and the short arm 4-2 is defined as the float connecting rod hinge hole 4-3. This hole is hinged to the main shaft 2-6 of the mechanism seat plane. The long arm 4-1 extends towards the main plane 2-4 of the mechanism seat in the upstream direction of the auxiliary road, while the short arm 4-2 extends towards the secondary plane 2-5 of the mechanism seat in the downstream direction of the auxiliary road. A roller mounting hole 4-4 is opened at the end of the short arm 4-2.

[0038] Specifically, the obtuse angle between the long arm 4-1 and the short arm 4-2 of the float connecting rod 4 allows the long arm 4-1 to extend upstream along the auxiliary road to obtain a larger float travel sensing range, while the short arm 4-2 extends downstream along the auxiliary road to effectively drive the roller 7 within the limited space of the mechanism seating plane 2-5. The length ratio of the long arm 4-1 to the short arm 4-2 is determined based on the ratio of the buoyancy required by the float 5 to the torque required to drive the plug connecting rod 6, so that a small change in the buoyancy of the float 5 can generate a torque sufficient to drive the transmission mechanism past the dead point at the end of the short arm 4-2.

[0039] Reference Figure 8 As shown, float 5 provides buoyancy to drive the anti-backflow self-control mechanism. Its density is less than that of the fluid. It is fixedly connected to the end of the long arm 4-1 of the float connecting rod 4, and has an irregular fan shape. Its thickness is slightly less than the z-direction distance between the main plane 2-4 of the mechanism seat and the main plane 3-2 of the mechanism cover. When float 5 is at its lowest position, its lower edge remains horizontal and is slightly higher than the inlet 2-2 of the mechanism seat; its right edge is vertical and basically fits against the vertical edge of the rear edge 2-8 of the mechanism seat. When float 5 is at its highest position, its upper edge remains horizontal and basically coincides with the upper edge of the main plane 2-4 of the mechanism seat.

[0040] Furthermore, the float 5 is irregularly fan-shaped, with both its upper and lower edges remaining horizontal. When the float 5 sinks to its lowest position, its lower edge is horizontal and slightly higher than the inlet 2-2 of the mechanism seat, and its right edge is in contact with the rear edge 2-8 of the mechanism seat. When the float 5 rises to its highest position, its upper edge coincides with the upper edge of the main plane 2-4 of the mechanism seat. The upper and lower limits of the float 5's stroke are achieved by the long arm 4-1 of the float connecting rod 4 contacting the upper and lower edges of the opening at the rear edge 3-4 of the mechanism cover.

[0041] Reference Figure 9 As shown, the plug connecting rod 6 is a secondary force transmission structure of the anti-backflow self-control mechanism, consisting of a slide rail 6-1 and a U-shaped short arm 6-2. The intersection of the two is defined as the plug connecting rod hinge hole 6-3, which is hinged to the secondary axis 2-7 on the secondary plane of the mechanism seat. The slide rail 6-1 has a raised structure in the middle of its track.

[0042] Specifically, the U-shaped short arm 6-2 of the plug connecting rod 6 opens towards the side of the secondary plane 2-5 of the mechanism seat. The U-shaped structure provides space for the secondary plane 2-5 of the mechanism seat and its secondary shaft 2-7, so that the plug 8 can complete the full stroke rotation from fully closed to fully open without interfering with the structure of the mechanism seat 2.

[0043] Reference Figure 10As shown, roller 7 is a force-transmitting component between float connecting rod 4 and plug connecting rod 6, and is dumbbell-shaped. The middle roller connecting shaft 7-1 is installed on the roller mounting hole 4-4. The two side discs 7-2 are in direct contact with the slide rail 6-1, and the protrusions of the slide rail 6-1 can prevent the two side discs 7-2 from derailing.

[0044] Reference Figure 11 As shown, the plug 8 is a circular thin sheet structure and is a key component for realizing the opening and closing of the auxiliary road. It is fixedly connected to the end of the U-shaped short arm 6-2.

[0045] The opening process of the plug 8 is jointly completed by two driving torques that intervene in sequence: the first driving torque is generated by the direct impact of the main flow of the auxiliary flow on the plug 8, and it acts promptly after the auxiliary pump starts; the second driving torque is generated by the float 5 rising and being transmitted to the plug connecting rod 6 through the transmission mechanism, and it intervenes after the auxiliary flow fluid fills the area where the float 5 is located; the superposition of the two torques ensures that the plug 8 can reliably pass the dead point position as the impact resistance of the main flow fluid gradually increases.

[0046] The sealing force of the plug 8 when closed comes from the fluid pressure difference between the main road interface 1-1 and the auxiliary road interface 1-5. The higher the fluid pressure in the main road, the greater the force of the plug 8 pressing the plug sealing ring 9, and the higher the sealing reliability. The anti-backflow self-locking mechanism does not have springs or other pre-tightening elements. The sealing clamping force is entirely passively provided by the fluid pressure difference, forming a pressure difference self-tightening sealing mechanism, which has self-reinforcing sealing characteristics under the high pressure condition of the main road.

[0047] The anti-backflow self-locking mechanism automatically returns to the safe state of the plug 8 being closed under any working condition where the auxiliary pipeline fluid pressure is lost, without the need for external control commands or energy input. When the system experiences a power outage, control failure, or auxiliary pipeline damage leading to a sudden drop in auxiliary pipeline pressure, the float 5 automatically sinks under the action of gravity due to the loss of buoyancy support. It drives the plug 8 to retract past the dead point through the transmission mechanism and quickly closes under the action of the main pipeline pressure, forming a fail-safe passive closing characteristic.

[0048] Reference Figure 12 As shown, the plug sealing ring 9 is a sealing structure between the plug 8 and the auxiliary flow channel. It is installed at the downstream outlet of the anti-backflow self-locking mechanism chamber 1-4 to ensure the sealing performance when the plug 8 is closed.

[0049] Reference Figure 13 As shown, the drain port is used to discharge fluid or impurities and consists of a drain port seat 10 and a drain port nut 11.

[0050] The drain port seat 10 is the main support structure for the drain port. The internal thread 10-1 of the drain port seat at the upper end is installed on the drain port interface 1-3, and the external thread 10-2 of the drain port seat is provided at the lower end.

[0051] Reference Figure 14 As shown, the drain nut 11 is screwed onto the external thread 10-2 of the drain port seat. It can be unscrewed when fluid or impurities need to be drained.

[0052] In this embodiment, the main pipeline is the primary fuel supply pipeline; under normal circumstances, as long as fuel is supplied, the main pipeline will always have fuel. The auxiliary pipeline is the secondary fuel supply pipeline; when the auxiliary pipeline runs out of fuel, it automatically shuts off under the action of the anti-backflow automatic control mechanism. This invention is applicable to operating conditions where both the main pipeline and the auxiliary pipeline have fuel (simultaneous fuel supply from both pipelines) and where the main pipeline has fuel but the auxiliary pipeline has no fuel (auxiliary pipeline fuel is shut off, and only the main pipeline supplies fuel).

[0053] Before describing the workflow, we first define the auxiliary path closed state, the "dead point" state, and the auxiliary path open state.

[0054] Auxiliary road closed status: such as Figure 3 In position (a), the float 5 sinks to its lowest point, its lower plane remains horizontal, and the long arm 4-1 directly contacts the lower edge of the opening of the mechanism cover 3-4 to achieve limiting; at this time, the plug 8 is completely closed and tightly fits the plug sealing ring 9. The roller 7 contacts the slide rail 6-1, but there is no interaction force. Define the angle between the short arm 4-2 of the float connecting rod 4 and the slide rail 6-1 of the plug connecting rod 6 as α. In this state, α is an obtuse angle (e.g., 166°, the specific angle is determined according to the structural parameters based on the nature and state of the incoming flow, except for 90°, the following angles are similar).

[0055] The initial obtuse angle α is determined by simultaneously satisfying the sealing reliability condition of the plug 8 and the full-process drivability condition of the transmission mechanism, and its value ranges from 135° to 170°; the acute angle α in the auxiliary road open state is determined by simultaneously satisfying the transmission self-locking reliability condition after passing the dead point and the geometric constraint condition of the float 5 floating stroke, and its value ranges from 60° to 85°; the designer calculates and selects the above angles based on the fluid density, the rated flow velocity of the main road and auxiliary road, the sealing ring specifications and the geometric parameters of each connecting rod.

[0056] "Dead point" state: such as Figure 3 In (b), when α = 90°, it is the "dead point" state. In this state, no matter how much impact force the plug 8 receives from the main fluid (i.e., no matter how much clockwise torque the slide rail 6-1 receives), the short arm 4-2 will not rotate.

[0057] After the transmission mechanism passes the dead point position, the plug 8 continues to fall back by an angle β in the transmission direction under the action of the fluid impact force from the main road interface 1-1, so that the included angle α is further reduced from 90° to the acute angle working position, forming a self-locking angle margin; the angle margin ensures that no fluid impact force of any size from the main road can drive the transmission mechanism to reverse back to the dead point position, thereby enhancing the robustness of the plug 8 in the open state.

[0058] Auxiliary road open status: such as Figure 3 In position (c), float 5 rises to its highest point, its upper plane remaining horizontal. Long arm 4-1 directly contacts the upper edge of the opening at the rear edge of mechanism cover 3-4 to achieve a limiting position. At this time, plug 8 is fully open, and the angle between the plane containing the plug surface and the x-axis is approximately 135°, with α being an acute angle (e.g., 78°). Under the impact of the main fluid, plug 8 experiences a force in the closing direction, and slide rail 6-1 experiences a clockwise torque. However, due to the acute angle α (e.g., 78°), short arm 4-2 will not rotate counterclockwise. Simultaneously, solely due to the buoyancy of float 5, short arm 4-2 will not rotate counterclockwise. Therefore, plug 8 remains open.

[0059] It should be noted that the solution of this invention can be adapted to the fluid properties of different auxiliary and main roads by changing the length of the force transmission arms such as the short arm 4-2 and the slide rail 6-1, thus possessing universality. Therefore, angles such as α are only qualitatively described as acute or obtuse, without making absolute limitations on specific values.

[0060] The detailed workflow is as follows: Switching from the state of "oil supply to the main line and no oil to the auxiliary line" to the state of "oil supply to both the main line and the auxiliary line": When the auxiliary line pump is turned on to supply oil, the fluid enters the anti-reverse self-locking mechanism compartment 1-4 via the auxiliary line interface 1-5. Since the projected area ratio of the anti-reverse self-locking mechanism on the yz plane of the flow passage is very small in the flow passage except for the blocking cover 8, the main flow of the auxiliary line fluid will directly impact the blocking cover 8, applying a torque that rotates it counterclockwise around the blocking cover link hinge hole 6-3, so as to drive the blocking cover 8 to open. Apart from the main flow that impacts the blocking cover 8, the remaining small portion of the fluid is defined as the auxiliary line fluid secondary flow. The auxiliary line fluid secondary flow flows rightward into the area of the anti-reverse self-locking mechanism. The anti-reverse self-locking mechanism bracket 1-6 applies an upward acting force to it when it flows rightward, and the anti-reverse self-locking mechanism base 1-7 and the mechanism seat inlet 2-2 apply an acting force that converges toward the middle in the z direction to it when it flows rightward. After the auxiliary line fluid secondary flow reaches the rear edge 2-8 of the mechanism seat, it no longer flows downstream. Pushed by the continuous incoming flow from the auxiliary line, it starts to flow upward after entering the mechanism seat inlet 2-2, driving the float 5 to generate buoyancy and causing the float 5 to move upward. The incoming flow from the auxiliary line causes the oil level in the anti-reverse self-locking mechanism compartment 1-4 to keep rising. When the oil level is higher than the highest point of the mechanism seat 2, since the upper part of the mechanism seat 2 is an open structure, the fluid will fill the space enclosed by the mechanism seat 2 and the mechanism cover 3, causing the float 5 to continue floating upward. The buoyancy of the float 5 acts on the long arm 4-1 of the float link 4, driving the long arm 4-1 to rotate clockwise around the float link hinge hole 4-3, and then transmitting the force to the short arm 4-2. The roller 7 is tangent to the slide rail 6-1, so the acting force of the roller 7 on the slide rail 6-1 is perpendicular to the surface of the slide rail 6-1. The short arm 4-2 transmits the clockwise torque to the slide rail 6-1 via the roller 7. Under the action of the vertical force, the slide rail 6-1 rotates counterclockwise around the blocking cover link hinge hole 6-3, and the U-shaped short arm 6-2 also rotates counterclockwise accordingly, so as to drive the blocking cover 8 to open. The blocking cover 8 is gradually opened under the combined action of the impact force F1 of the main flow of the auxiliary line fluid and the thrust F2 of the U-shaped short arm 6-2 driven by the buoyancy of the float 5. At this time, the resultant force of F1 and F2 on the blocking cover 8 is greater than the closing acting force F3 of the incoming flow from the main line on the blocking cover 8, that is, F3<F1+F2. As the blocking cover 8 opens, the F3 it receives gradually increases, but before F3≥F1+F2, the short arm 4-2 of the float link 4 has already passed the "dead point" clockwise. Once past the "dead point", the blocking cover 8 will also fall back by a small angle β clockwise, which improves the robustness of the blocking cover 8. No matter how large F3 is, the blocking cover 8 will maintain a stable open state. So far, simultaneous oil supply to the auxiliary line and the main line is realized.

[0061] Switching from "both main and auxiliary channels are supplied with oil" to "main channel is supplied with oil, auxiliary channel is not": As the oil supply to the auxiliary channel gradually decreases, the impact force F1 of the main flow of fluid on the plug 8 decreases. Under the impact of the main flow, the plug 8 tends to close, and the slide rail 6-1 experiences a clockwise trend torque. At the same time, the secondary flow of fluid entering the anti-backflow self-locking mechanism also gradually decreases, causing the buoyancy of the float 5 to decrease. As the flow of fluid to the auxiliary channel decreases, the oil level in the anti-backflow self-locking mechanism chamber 1-4 continues to drop. When the oil level is lower than the highest point of the mechanism seat 2, the float 5 loses the buoyancy brought by the inflow of some fluid from the mechanism seat 2, and its buoyancy further decreases and is gradually replaced by its own weight. The weight of the float 5 acts on the long arm 4-1 of the float connecting rod 4, driving the long arm 4-1 to rotate counterclockwise around the float connecting rod hinge hole 4-3, thereby transmitting the force to the short arm 4-2, generating a torque that drives the short arm 4-2 to rotate counterclockwise. At this point, the short arm 4-2 needs to resist the closing tendency of the plug 8 until it rotates counterclockwise and passes the "dead point". As mentioned above, the small angle β is very small, and the force required to resist the clockwise rotation of the plug 8 during the process of passing the dead point is very small. The buoyancy of the float 5 is dominant, which increases the feasibility of passing the dead point. After passing the dead point, F3 ≥ F1 + F2. After passing the dead point, the short arm 4-2 has a tendency to rotate counterclockwise. At this time, the vertical force from the roller 7 on the slide rail 6-1 becomes smaller and smaller. Under the continuous impact force F3 of the main flow on the plug 8, and the decreasing constraint force on the slide rail 6-1 after leaving the dead point, the plug 8 gradually closes. Finally, the working condition of supplying oil only to the main flow and closing the auxiliary flow without oil is achieved, and the fluid in the main flow will not flow back to the auxiliary flow.

[0062] Draining fluid or impurities: When it is necessary to drain fluid or impurities, simply unscrew the drain nut 11.

[0063] The drain port seat 10 can be removed for maintenance.

[0064] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A three-way valve based on a mechanical anti-backflow self-locking mechanism, characterized in that, include: The valve body (1) is provided with a main line interface (1-1), at least one auxiliary line interface (1-5), a main line interface (1-2) and an oil drain interface (1-3). The main line interface (1-1) and the auxiliary line interface (1-5) converge in the valve body (1) and flow to the main line interface (1-2). The oil drain interface (1-3) is located downstream of the convergence point. The anti-backflow self-locking mechanism is installed in the auxiliary channel between the auxiliary channel interface (1-5) and the junction point, and includes a plug (8) and a float (5). The float (5) is installed in the auxiliary channel and moves under the action of the fluid in the auxiliary channel, thereby driving the transmission mechanism to open the plug (8). The transmission mechanism has a dead point position. When the plug (8) is opened and passes the dead point position, the transmission mechanism enters the self-locking state. At this time, the fluid impact force from the main channel interface (1-1) acts... The closing force of the plug (8) is converted into a self-locking internal force to maintain the opening state of the plug (8) through the transmission mechanism. When no fluid flows through the auxiliary channel, the float (5) resets and drives the plug (8) to return past the dead point position through the transmission mechanism. The plug (8) closes under the action of the fluid impact force from the main channel interface (1-1), thereby preventing the fluid from flowing back from the main channel interface (1-1) and / or the main channel interface (1-2) to the auxiliary channel interface (1-5).

2. The three-way valve based on a mechanical anti-backflow self-locking mechanism according to claim 1, characterized in that: The anti-backflow self-locking mechanism also includes a mechanism base (2) and a mechanism cover (3). The mechanism base (2) and the mechanism cover (3) together form an accommodating space, and the float (5) is set in the accommodating space. The transmission mechanism includes a float connecting rod (4) and a plug connecting rod (6). The float (5) is fixedly connected to one end of the float connecting rod (4), and the plug (8) is fixedly connected to one end of the plug connecting rod (6). The other end of the float connecting rod (4) and the plug connecting rod (6) are connected by a roller (7).

3. A three-way valve based on a mechanical anti-backflow self-locking mechanism according to claim 2, characterized in that: The width of the mechanism seat (2) is smaller than the diameter of the auxiliary flow channel. One end facing the auxiliary interface (1-5) has a flow guiding structure. The flow guiding structure includes an acute-angled leading edge (2-1) at the top and a trumpet-shaped inlet (2-2) at the bottom. The large end of the trumpet-shaped inlet (2-2) faces the auxiliary interface (1-5) and is used to introduce the auxiliary flow into the interior of the mechanism seat (2). The mechanism seat (2) includes an irregular fan-shaped main plane (2-4), and the inner arc of the main plane (2-4) extends towards the center to form a secondary plane (2-5); wherein, the two radial sides of the fan-shaped main plane (2-4) serve as the travel limit of the float (5); the secondary plane (2-5) is provided with a main shaft (2-6) and a secondary shaft (2-7), the float connecting rod (4) is hinged to the main shaft (2-6), and the plug connecting rod (6) is hinged to the secondary shaft (2-7); the float connecting rod (4) and the plug connecting rod (6) swing within the space of the secondary plane (2-5).

4. A three-way valve based on a mechanical anti-backflow self-locking mechanism according to claim 3, characterized in that: The float connecting rod (4) is an L-shape consisting of a long arm (4-1) and a short arm (4-2), with an obtuse angle between the two arms. The float (5) is fixedly connected to the end of the long arm (4-1). The float connecting rod (4) has a float connecting rod hinge hole (4-3) at the intersection of the long arm (4-1) and the short arm (4-2). The float connecting rod is rotatably connected to the main shaft (2-6) of the secondary plane of the mechanism seat (2) through the float connecting rod hinge hole (4-3). The plug connecting rod (6) has a slide rail (6-1) and a U-shaped short arm (6-2), and a plug connecting rod hinge hole (6-3) is provided at the intersection of the two. The plug connecting rod is rotatably connected to the secondary axis (2-7) of the secondary plane of the mechanism seat (2) through the plug connecting rod hinge hole (6-3); the plug (8) is fixedly connected to the end of the U-shaped short arm (6-2); The roller (7) is mounted on the roller mounting hole (4-4) at the end of the short arm (4-2) and rolls in contact with the slide rail (6-1).

5. A three-way valve based on a mechanical anti-backflow self-locking mechanism according to claim 4, characterized in that: The roller (7) is dumbbell-shaped, including a middle roller connecting shaft (7-1) and two rollers (7-2) on both sides. The roller connecting shaft (7-1) passes through the roller mounting hole (4-4), and the two rollers (7-2) on both sides make rolling contact with the surface of the slide rail (6-1). The slide rail (6-1) has a raised structure in the middle of the track to prevent the two rollers (7-2) from derailing.

6. A three-way valve based on a mechanical anti-backflow self-locking mechanism according to claim 5, characterized in that: The included angle α between the short arm (4-2) of the float connecting rod (4) and the slide rail (6-1) of the plug connecting rod (6) is an obtuse angle when the plug (8) is closed and an acute angle when the plug (8) is open; the included angle α is 90° at the dead point position.

7. A three-way valve based on a mechanical anti-backflow self-locking mechanism according to claim 6, characterized in that: The density of the float (5) is less than that of the fluid. When fluid flows through the auxiliary channel, it floats up due to buoyancy, which in turn drives the float connecting rod (4) to rotate. When no fluid flows through the auxiliary channel, the float (5) sinks under the action of gravity, which in turn drives the float connecting rod (4) to rotate in the opposite direction.

8. A three-way valve based on a mechanical anti-backflow self-locking mechanism according to claim 7, characterized in that: The auxiliary flow channel of the valve body (1) is provided with a backflow prevention self-locking mechanism bracket (1-6) and a backflow prevention self-locking mechanism base (1-7); the backflow prevention self-locking mechanism bracket (1-6) is an inclined structure, which is set at an angle with the incoming flow direction, and its width is 1 / 5 of the diameter of the auxiliary flow channel, so that the incoming flow is diverted to the area where the float (5) is located; the backflow prevention self-locking mechanism base (1-7) is welded to the backflow prevention self-locking mechanism bracket (1-6) and is used to install the mechanism seat (2).

9. A three-way valve based on a mechanical anti-backflow self-locking mechanism according to claim 8, characterized in that: The drain port includes a drain port seat (10) and a drain port nut (11). The upper end of the drain port seat (10) is installed on the drain port interface (1-3) through the drain port seat internal thread (10-1). The lower end of the drain port seat (10) is provided with a drain port seat external thread (10-2). The drain port nut (11) is screwed onto the drain port seat external thread (10-2). When the drain port nut (11) is unscrewed, the drain port is open to discharge fluid or impurities.

10. A method for preventing backflow of a three-way valve based on a mechanical anti-backflow self-locking mechanism as described in any one of claims 1-9, characterized in that, Includes the following steps: Self-locking opening steps during auxiliary pipeline oil supply: When the auxiliary pipeline pump starts supplying oil, the fluid enters the auxiliary pipeline flow channel through the auxiliary pipeline interface (1-5). Part of the fluid directly impacts the plug (8) to generate an opening torque, while the other part of the fluid is diverted to the area where the float (5) is located, causing the float (5) to float. The buoyancy of the float (5) is transmitted through the transmission mechanism and assists in driving the plug (8) to open. When the transmission mechanism moves past the dead point position, it enters the self-locking state. The fluid impact force from the main pipeline is converted into a self-locking internal force that maintains the opening state of the plug (8) through the transmission mechanism, so that the plug (8) remains fully open. Backflow prevention shutdown procedure when auxiliary pipeline oil supply is interrupted: When the auxiliary pipeline pump is shut down and the auxiliary pipeline oil supply is interrupted, the fluid in the area where the float (5) is located decreases, and the float (5) sinks under the action of gravity. Through the transmission mechanism, the plug (8) is driven to return to the dead point position and release the self-locking state. The plug (8) is quickly closed under the action of the fluid impact force from the main pipeline and is tightly fitted with the plug sealing ring (9) to prevent the fluid from the main pipeline and the main pipeline from flowing back to the auxiliary pipeline.

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