Stop valve with double-valve-clack structure and opening and closing method thereof

Abstract

The invention discloses a double-valve-clack structure stop valve and an opening and closing method thereof, and belongs to the technical field of check valves. Comprising a valve pipe, the valve pipe is used for being installed at the connecting end of a conveying pipeline, an opening and closing assembly is installed in the liquid inlet end of the valve pipe, a butterfly valve assembly is installed at the liquid outlet end of the valve pipe, the opening direction of the opening and closing assembly is the same as that of the butterfly valve assembly, and when the opening and closing assembly and the butterfly valve assembly are closed at the same time, the opening and closing assembly is closed. The portion, located between the opening and closing assembly and the butterfly valve assembly, of the valve pipe forms a closed space, a confluence assembly is installed at the liquid outlet end of the butterfly valve assembly, and the central axis of the confluence assembly and the central axis of the butterfly valve assembly are overlapped. When the opening and closing assembly and the butterfly valve are used in a matched mode, it can be ensured that media continue to move forwards in the preset direction without the backflow phenomenon even if sudden stop occurs.

Description

Technical Field

[0001] The present invention belongs to the technical field of check valves, and in particular relates to a stop valve with a double-valve flap structure and an opening and closing method thereof. Background Art

[0002] An automatic check valve is a valve used to prevent reverse flow of fluid in a piping system. It usually opens and closes automatically based on the pressure and flow rate of the fluid without the need for external operation.

[0003] Existing spring-loaded automatic check valves rely on the spring's rebound force to prevent fluid backflow. However, the spring of such automatic check valves can easily fail over time. When the spring fails, the valve disc cannot close when fluid backflows, rendering the system unable to prevent reverse flow. Summary of the Invention

[0004] Purpose of the invention: To provide a double-valve-flap stop valve and its opening and closing method, which solves the above-mentioned problems existing in the prior art.

[0005] Technical solution: A double-valve flap structure stop valve, including a valve pipe, which is used to be installed at the connecting end of the conveying pipeline, an opening and closing component is installed in the liquid inlet end of the valve pipe, and a butterfly valve assembly is installed at the liquid outlet end of the valve pipe. The opening direction of the opening and closing component is the same as that of the butterfly valve assembly. When the opening and closing component and the butterfly valve assembly are closed at the same time, the valve pipe located between the opening and closing component and the butterfly valve assembly forms a closed space, and a confluence component is installed at the liquid outlet end of the butterfly valve assembly. The central axis of the confluence component overlaps with the central axis of the butterfly valve assembly.

[0006] Preferably, it also includes a drainage component, which is arranged in the valve tube, and the opening and closing component is partially inserted into the drainage component, wherein the drainage component includes a plurality of mounting rods, one end of the mounting rods is circumferentially arrayed on the inner wall of the valve tube, and the other end of the mounting rod is installed with a mounting ring, which is funnel-shaped, the opening and closing component is partially inserted into the small diameter end of the mounting ring, and the large diameter end of the mounting ring is installed with a collecting ring.

[0007] Preferably, the arc length of the mounting ring is calculated by formula (1), which is as follows:

[0008]

[0009] Where: z represents the maximum radius of the mounting ring; y represents the length of the mounting ring; x1 represents the distance from the reference point to the front end of the mounting ring; n f Indicates the profile adjustment parameters of the installation arc.

[0010] Preferably, the arc length of the collecting ring is calculated by formula (2), which is as follows:

[0011]

[0012] Where: e represents the length of the collection ring; x2 represents the distance from the reference point to the rear end of the collection ring, n a Indicates the contour adjustment parameters of the converging arc.

[0013] Preferably, the valve pipe includes a clamping ring, the opening and closing assembly is installed in the clamping ring, one end of the clamping ring is connected to the elliptical ball ring, the drainage assembly is installed in the elliptical ball ring, the other end of the elliptical ball ring is installed with a connecting ring, and the butterfly valve assembly is installed at the end of the connecting ring away from the elliptical ball ring, wherein the maximum radius of the elliptical ball ring is calculated by formula (3), which is as follows:

[0014]

[0015] Where: r2 represents the radius of the clamping ring, and r3 represents the maximum radius of the mounting ring.

[0016] Preferably, the opening and closing assembly includes a movable valve flap, the valve tube is provided with an annular protrusion inside near the movable valve flap, the end of the movable valve flap near the annular protrusion is provided with an annular groove, the annular groove is used to sleeve the annular protrusion, the other end of the movable valve flap is provided with a movable rod, the central axis of the movable rod overlaps with the central axis of the movable valve flap, the movable rod is inserted into the small diameter end of the guide ring, and a reset spring is sleeved on the movable rod, one end of the reset spring is connected to the guide ring, and the other end of the reset spring is connected to the movable valve flap.

[0017] Preferably, the butterfly valve assembly includes a butterfly valve ring, which is installed at the liquid outlet of the valve pipe, a support rod is installed in the butterfly valve ring, two groups of rotating valve discs are rotatably installed on the support rod, an abutment rod is installed in the butterfly valve ring, the abutment rod and the support rod are placed side by side, and the support rod has two groups of torsion springs sleeved from top to bottom, one end of the torsion spring abuts the rotating valve disc, and the other end of the torsion spring abuts the abutment rod.

[0018] Preferably, the torque of the torsion spring is calculated by formula (4), which is as follows:

[0019]

[0020] Where: d represents the diameter of the torsion spring wire, n represents the number of effective turns; A represents the median diameter of the torsion spring; F represents the elastic modulus;

[0021] After the torque of the torsion spring is completed, the angular velocity increment generated by the rotating valve disc under the force of the fluid and the torsion spring is calculated by formula (5). Formula (5) is as follows:

[0022]

[0023] Where: m represents the mass of the rotating valve disc; Δt represents the time step; N represents the torque exerted by the fluid on the rotating valve disc; r4 represents the length from the center of mass of the rotating valve disc to the center of rotation.

[0024] Preferably, the confluence assembly includes an external pipe, which is sleeved on the liquid outlet end of the butterfly valve assembly. The outer wall of the sleeved pipe is connected to the return pipe in a circumferential array. The return pipe includes an inclined pipe and an arc pipe. The angle between the inclined pipe and the external pipe is toward the rotating valve disc. The end of the inclined pipe away from the external pipe is connected to the arc pipe. The arc pipe is connected to the external pipe, and the outlet end of the arc pipe is toward the end of the external pipe away from the rotating valve disc.

[0025] A method for opening and closing a double-valve-flap stop valve comprises the following steps:

[0026] S1. When fluid flows through the delivery pipe at the input end of the stop valve, the fluid impacts the opening and closing assembly, squeezing the return spring in the opening and closing assembly, causing the movable valve disc to separate from the annular protrusion. The movable rod is inserted into the drainage assembly. At this time, the fluid flows into the valve pipe, generating an impact force on the butterfly valve assembly, which pushes the rotating valve disc of the butterfly valve assembly open. The fluid can then smoothly pass through the stop valve and flow into the delivery pipe at the output end of the stop valve.

[0027] S2. When the fluid in the delivery pipe at the stop valve input stops flowing, the fluid in the delivery pipe at the stop valve output flows back, part of the backflowing fluid flows into the external pipe, and part flows into the return pipe. The fluid flowing into the return pipe merges with the fluid flowing into the external pipe, forming a flow impact on the rotating disc in the butterfly valve assembly. The rotating disc closes quickly under the impact of the fluid and the rebound of the torsion spring;

[0028] S3. During the closing process of the butterfly valve assembly, part of the fluid flows into the valve pipe along the gap of the butterfly valve assembly. Under the action of the drainage assembly, the fluid flowing into the valve pipe is gathered, forming an impact force on the moving rod in the opening and closing assembly, and with the cooperation of the reset spring, the moving valve disc is quickly closed.

[0029] Beneficial effects: The present invention relates to a double-valve-flap structure globe valve and an opening and closing method thereof, wherein the opening and closing assembly and the butterfly valve assembly automatically open under the impact of the fluid, and the fluid can flow smoothly through the globe valve. After the fluid stops flowing, the fluid in the delivery pipe at the output end of the butterfly valve assembly flows back, and the external pipe in the merging assembly cooperates with the return pipe to form a directional flow in the external pipe, thereby increasing the directional impact on the rotating valve disc and causing the rotating valve disc to close quickly.

[0030] Secondly, during the valve closing process, fluid enters the valve cavity through the gap between the rotating disc and the valve body. At this point, the diversion device guides this fluid toward the mounting ring, exerting an impact force on the movable rod inserted into the mounting ring, prompting the first opening and closing mechanism to quickly activate and complete the seal. This process not only speeds up the response of the entire system and reduces the time the liquid remains in the pipeline, but also maintains unidirectional flow even in the absence of external power, effectively preventing reverse flow. When used in conjunction with the opening and closing assembly and butterfly valve, even in the event of a sudden stop, the medium can continue to flow in the intended direction without backflow. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0032] Figure 2 It is a cross-sectional view of the internal structure of the present invention;

[0033] Figure 3 It is a schematic diagram of fluid reflux of the present invention;

[0034] Figure 4 for Figure 3 A magnified view of point A;

[0035] Figure 5 Schematic diagram of a butterfly valve assembly of the present invention.

[0036] Figures 1 to 5 The accompanying drawings are marked as follows: 1. valve pipe; 2. opening and closing assembly; 3. butterfly valve assembly; 4. confluence assembly; 5. drainage assembly;

[0037] 101. Snap ring; 102. Oval ball ring; 103. Connecting ring;

[0038] 201, movable valve disc; 202, annular protrusion; 203, annular groove; 204, movable rod; 205, return spring;

[0039] 301, butterfly valve ring; 302, support rod; 303, rotating valve disc; 304, abutment rod; 305, torsion spring;

[0040] 401, external pipe; 402, inclined pipe; 403, curved pipe;

[0041] 501. Mounting rod; 502. Mounting ring; 503. Collection ring. DETAILED DESCRIPTION

[0042] like Figures 1 to 5As shown, the present invention provides a technical solution: a double-valve flap structure stop valve, comprising a valve pipe 1, an opening and closing component 2, a butterfly valve component 3, a confluence component 4 and a drainage component 5, the valve pipe 1 is used to be installed at the connection between the conveying pipes, the opening and closing component 2 is installed in the liquid inlet end of the valve pipe 1, and the butterfly valve component 3 is installed at the liquid outlet end of the valve pipe 1, the drainage component 5 is arranged in the valve pipe 1 and is located between the opening and closing component 2 and the butterfly valve component 3, the opening direction of the opening and closing component 2 and the butterfly valve component 3 is the same, when the opening and closing component 2 and the butterfly valve component 3 are closed at the same time, the valve pipe 1 located between the opening and closing component 2 and the butterfly valve component 3 forms a closed space, the liquid outlet end of the butterfly valve component 3 is installed with a confluence component 4, the central axis of the confluence component 4 overlaps with the central axis of the butterfly valve component 3, the drainage component 5 is arranged in the valve pipe 1, and the opening and closing component 2 is partially inserted into the drainage component 5, as shown Figure 3 As shown, the diversion assembly 5 includes a plurality of mounting rods 501, one end of the mounting rods 501 is circumferentially arrayed and mounted on the inner wall of the valve tube 1, and the other end of the mounting rods 501 is mounted with a mounting ring 502, which is funnel-shaped. The opening and closing assembly 2 is partially inserted into the small-diameter end of the mounting ring 502, and the large-diameter end of the mounting ring 502 is mounted with a collecting ring 503. When fluid flows into the delivery pipeline, the opening and closing assembly 2 and the butterfly valve assembly 3 are automatically opened under the impact of the fluid, and the fluid can flow smoothly through the stop valve. After the fluid stops flowing, the fluid in the delivery pipeline at the output end of the butterfly valve assembly 3 flows back, and the external pipeline 401 in the merging assembly 4 cooperates with the return pipe to form a directional flow in the external pipeline 401 of the return pipe, thereby increasing the directional impact on the rotating valve disc 303 and causing the rotating valve disc 303 to close quickly. During the closing process of the butterfly valve assembly 3, the fluid enters the valve cavity through the gap between the rotating valve disc and the valve body. At this time, the diversion device will guide these fluids to flow towards the installation ring 502, generating an impact force on the movable rod 204 inserted into the installation ring 502, prompting the first opening and closing mechanism to move quickly to complete the seal. This process not only speeds up the response speed of the entire system and reduces the residence time of the liquid in the pipeline, but also maintains a unidirectional flow state even in the absence of external power, effectively preventing the occurrence of reverse flow. When the opening and closing component 2 and the butterfly valve are used together, even in the event of a sudden stop, the medium can continue to flow in the predetermined direction without backflow.

[0043] In a further embodiment, the arc length of the mounting ring 502 is calculated by formula (1), which is as follows:

[0044]

[0045] Wherein: z represents the maximum radius of the mounting ring 502; y represents the length of the mounting ring 502; x1 represents the distance between the reference point and the front end of the mounting ring 502; nf represents the profile adjustment parameter of the arc of the mounting ring 502. The arc length of the collecting ring 503 is calculated by formula (2), which is as follows:

[0046]

[0047] Wherein: e represents the length of the collecting ring 503; x2 represents the distance between the reference point and the rear end of the collecting ring 503, and na represents the profile adjustment parameter of the arc of the collecting ring 503. By calculating the arc lengths of the mounting ring 502 and the collecting ring 503, a drainage assembly 5 that can quickly collect the reflux fluid can be obtained. That is, during the fluid reflux process, a thrust is applied to the moving rod 204 to quickly close the moving valve flap 201.

[0048] In a further embodiment, the valve pipe 1 includes a clamping ring 101, the opening and closing assembly 2 is installed in the clamping ring 101, one end of the clamping ring 101 is connected to the elliptical ball ring 102, the drainage assembly 5 is installed in the elliptical ball ring 102, the other end of the elliptical ball ring 102 is installed with a connecting ring 103, and the butterfly valve assembly 3 is installed at the end of the connecting ring 103 away from the elliptical ball ring 102, wherein the maximum radius of the elliptical ball ring 102 is calculated by formula (3), which is as follows:

[0049]

[0050] In the formula: r2 represents the radius of the clamping ring 101, r3 represents the maximum radius of the mounting ring 502, and the relationship between the elliptical ball ring 102 and the drainage component 5 is calculated. After the fluid flushes the opening and closing component 2, with the cooperation of the elliptical ball ring 102 and the drainage component 5, it quickly flows to the butterfly valve component 3, and the butterfly valve component 3 can be quickly flushed open to form a directional flow of fluid.

[0051] In a further embodiment, the opening and closing component 2 includes a movable valve flap 201, and the valve tube 1 is provided with an annular protrusion 202 inside near the movable valve flap 201, and an annular groove 203 is installed at the end of the movable valve flap 201 near the annular protrusion 202, and a seal is formed by the cooperation of the annular groove 203 and the annular protrusion 202. The other end of the movable valve flap 201 is provided with a movable rod 204, and the central axis of the movable rod 204 overlaps with the central axis of the movable valve flap 201. The movable rod 204 is inserted into the small diameter end of the guide ring, and a reset spring 205 is sleeved on the movable rod 204. One end of the reset spring 205 is connected to the guide ring, and the other end of the reset spring 205 is connected to the movable valve flap 201. Under the cooperation of the movable rod 204 and the reset spring 205, the movable valve flap 201 moves to form the opening or closing of the opening and closing component 2.

[0052] In a further embodiment, the butterfly valve assembly 3 includes a butterfly valve ring 301, which is installed at the liquid outlet of the valve pipe 1. A support rod 302 is installed in the butterfly valve ring 301, and two groups of rotating valve discs 303 are rotatably installed on the support rod 302. An abutment rod 304 is installed in the butterfly valve ring 301, and the abutment rod 304 is placed in parallel with the support rod 302. The support rod 302 has two groups of torsion springs 305 sleeved from top to bottom, one end of the torsion spring 305 abuts the rotating valve disc 303, and the other end of the torsion spring 305 abuts the abutment rod 304, wherein the torque of the torsion spring 305 is calculated by formula (4), and formula (4) is as follows:

[0053]

[0054] Where: d represents the wire diameter of the torsion spring 305, n represents the number of effective turns; A represents the median diameter of the torsion spring 305; F represents the elastic modulus;

[0055] After the torque of the torsion spring 305 is completed, the angular velocity increment generated by the rotating valve disc 303 under the action of the fluid and the torsion spring 305 is calculated by formula (5), which is as follows:

[0056]

[0057] Where m represents the mass of the rotating valve disc 303; Δt represents the time step; N represents the magnitude of the torque exerted by the fluid on the rotating valve disc 303; and r4 represents the length from the center of mass of the rotating valve disc 303 to the center of rotation. By calculating the calculated torque of the torsion spring 305, the rotating valve disc 303 can open and close smoothly during the fluid flow process.

[0058] In a further embodiment, the confluence assembly 4 includes an external pipe 401, which is sleeved on the liquid outlet end of the butterfly valve assembly 3. The outer wall of the sleeved pipe is connected to the return pipe in a circumferential array. The return pipe includes an inclined pipe 402 and an arc pipe 403. The angle between the inclined pipe 402 and the external pipe 401 is toward the rotating valve flap 303. The end of the inclined pipe 402 away from the external pipe 401 is connected to the arc pipe 403. The arc pipe 403 is connected to the external pipe 401, and the outlet end of the arc pipe 403 is toward the end of the external pipe 401 away from the rotating valve flap 303. As shown in Figure *, with the cooperation of the external pipe 401 and the return pipe, the reflux fluid is merged in the external pipe 401 to form a directional fluid, which forms a strong impact on the rotating valve flap 303, so that the rotating valve flap 303 can be quickly closed.

[0059] Through the above technical solution, the present invention can achieve the following working process:

[0060] A method for opening and closing a stop valve with a double-valve flap structure. When fluid flows through the delivery pipeline at the input end of the stop valve, the fluid impacts the opening and closing component 2, squeezes the return spring 205 in the opening and closing component 2, and causes the movable valve flap 201 to disengage from the annular protrusion 202. The movable rod 204 is inserted into the drainage component 5. At this time, the fluid flows into the valve pipe 1, generating an impact force on the butterfly valve component 3, and flushing open the rotating valve flap 303 of the butterfly valve component 3. The fluid can then pass through the stop valve smoothly and flow into the delivery pipeline at the output end of the stop valve.

[0061] When the fluid in the delivery pipe at the input end of the stop valve stops flowing, the fluid in the delivery pipe at the output end of the stop valve flows back, and part of the returned fluid flows into the external pipe 401, and part flows into the return pipe. The fluid flowing into the return pipe merges with the fluid flowing into the external pipe 401, forming a flow impact on the rotating valve disc 303 in the butterfly valve assembly 3. The rotating valve disc 303 closes quickly under the impact of the fluid and the rebound of the torsion spring 305. During the closing process of the butterfly valve assembly 3, part of the fluid flows into the valve pipe 1 along the gap of the butterfly valve assembly 3. Under the action of the diversion assembly 5, the fluid flowing into the valve pipe 1 is gathered, forming an impact force on the moving rod 204 in the opening and closing assembly 2, and with the cooperation of the reset spring 205, the moving valve disc 201 is quickly closed.

[0062] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and these equivalent transformations all fall within the scope of protection of the present invention.

Claims

1. A double-valve-flap stop valve, characterized in that: The invention comprises a valve pipe (1), wherein the valve pipe (1) is used to be installed at the connection end of a conveying pipeline, an opening and closing component (2) is installed in the liquid inlet end of the valve pipe (1), and a butterfly valve component (3) is installed at the liquid outlet end of the valve pipe (1), the opening direction of the opening and closing component (2) and the butterfly valve component (3) are the same, and when the opening and closing component (2) and the butterfly valve component (3) are closed at the same time, the valve pipe (1) located between the opening and closing component (2) and the butterfly valve component (3) forms a closed space, and a confluence component (4) is installed at the liquid outlet end of the butterfly valve component (3), and the central axis of the confluence component (4) overlaps with the central axis of the butterfly valve component (3).

2. A double-valve-flap stop valve according to claim 1, characterized in that: It also includes a drainage component (5), the drainage component (5) is arranged in the valve tube (1), and the opening and closing component (2) is partially inserted into the drainage component (5), wherein the drainage component (5) includes a plurality of mounting rods (501), one end of the mounting rods (501) is circumferentially arrayed and mounted on the inner wall of the valve tube (1), and the other end of the mounting rods (501) is mounted with a mounting ring (502), and the mounting ring (502) is funnel-shaped, the opening and closing component (2) is partially inserted into the small diameter end of the mounting ring (502), and the large diameter end of the mounting ring (502) is mounted with a collecting ring (503).

3. A double-valve-flap stop valve according to claim 2, characterized in that: The arc length of the mounting ring (502) is calculated by formula (1), which is as follows: Wherein: z represents the maximum radius of the mounting ring (502); y represents the length of the mounting ring (502); x1 represents the distance from the reference point to the front end of the mounting ring (502); and nf represents the profile adjustment parameter of the arc of the mounting ring (502).

4. A double-valve-flap stop valve according to claim 2, characterized in that: The arc length of the collecting ring (503) is calculated by formula (2), which is as follows: In the formula, e represents the length of the collecting ring (503); x2 represents the distance between the reference point and the rear end of the collecting ring (503); and na represents the profile adjustment parameter of the arc of the collecting ring (503).

5. A double-valve-flap stop valve according to claim 2, characterized in that: The valve tube (1) comprises a clamping ring (101), the opening and closing assembly (2) is installed in the clamping ring (101), one end of the clamping ring (101) is connected to an elliptical ball ring (102), the drainage assembly (5) is installed in the elliptical ball ring (102), the other end of the elliptical ball ring (102) is installed with a connecting ring (103), and the butterfly valve assembly (3) is installed at the end of the connecting ring (103) away from the elliptical ball ring (102), wherein the maximum radius of the elliptical ball ring (102) is calculated by formula (3), and formula (3) is as follows: Wherein: r2 represents the radius of the clamping ring (101), and r3 represents the maximum radius of the mounting ring (502).

6. A double-valve-flap stop valve according to claim 1, characterized in that: The opening and closing component (2) comprises a movable valve flap (201); an annular protrusion (202) is provided inside the valve tube (1) near the movable valve flap (201); an annular groove (203) is provided at the end of the movable valve flap (201) near the annular protrusion (202); the annular groove (203) is used to sleeve the annular protrusion (202); a movable rod (204) is provided at the other end of the movable valve flap (201); the central axis of the movable rod (204) overlaps with the central axis of the movable valve flap (201); the movable rod (204) is inserted into the small diameter end of the guide ring; a reset spring (205) is sleeved on the movable rod (204); one end of the reset spring (205) is connected to the guide ring; and the other end of the reset spring (205) is connected to the movable valve flap (201).

7. A double-valve-flap stop valve according to claim 1, characterized in that: The butterfly valve assembly (3) comprises a butterfly valve ring (301), the butterfly valve ring (301) being mounted at the liquid outlet of the valve pipe (1), a support rod (302) being mounted inside the butterfly valve ring (301), two groups of rotating valve flaps (303) being rotatably mounted on the support rod (302), an abutment rod (304) being mounted inside the butterfly valve ring (301), the abutment rod (304) being arranged in parallel with the support rod (302), the support rod (302) being sleeved with two groups of torsion springs (305) from top to bottom, one end of the torsion spring (305) abutting against the rotating valve flap (303), and the other end of the torsion spring (305) abutting against the abutment rod (304).

8. A double-valve-flap stop valve according to claim 7, characterized in that: The torque of the torsion spring (305) is calculated by formula (4), which is as follows: Wherein: d represents the wire diameter of the torsion spring (305), n represents the effective number of turns; A represents the median diameter of the torsion spring (305); F represents the elastic modulus; After the torque of the torsion spring (305) is completed, the angular velocity increment generated by the rotating valve disc (303) under the action of the fluid and the torsion spring (305) is calculated by formula (5), and the formula (5) is as follows: Wherein: m represents the mass of the rotating valve disc (303); Δt represents the time step; N represents the magnitude of the torque exerted by the fluid on the rotating valve disc (303); and r4 represents the length from the center of mass of the rotating valve disc (303) to the center of rotation.

9. A double-valve-flap stop valve according to claim 1, characterized in that: The confluence assembly (4) comprises an external pipe (401), the external pipe (401) is sleeved on the liquid outlet end of the butterfly valve assembly (3), the outer wall of the sleeved pipe is connected to a return pipe in a circumferential array, the return pipe comprises an inclined pipe (402) and an arc-shaped pipe (403), the angle between the inclined pipe (402) and the external pipe (401) is directed toward the rotating valve flap (303), the end of the inclined pipe (402) away from the external pipe (401) is connected to the arc-shaped pipe (403), the arc-shaped pipe (403) is connected to the external pipe (401), and the outlet end of the arc-shaped pipe (403) is directed toward the end of the external pipe (401) away from the rotating valve flap (303).

10. A method for opening and closing a stop valve with a double valve flap structure, used in conjunction with a stop valve with a double valve flap structure as claimed in any one of claims 1 to 9 to achieve fluid interception, characterized in that: The following steps are involved: S1. When fluid flows through the delivery pipeline at the input end of the stop valve, the fluid impacts the opening and closing component (2), squeezes the return spring (205) in the opening and closing component (2), and causes the movable valve flap (201) to separate from the annular protrusion (202). The movable rod (204) is inserted into the drainage component (5). At this time, the fluid flows into the valve pipe (1), generating an impact force on the butterfly valve component (3), and flushing open the rotating valve flap (303) of the butterfly valve component (3). The fluid can then smoothly pass through the stop valve and flow into the delivery pipeline at the output end of the stop valve. S2. When the fluid in the delivery pipeline at the input end of the stop valve stops flowing, the fluid in the delivery pipeline at the output end of the stop valve flows back, and part of the returned fluid flows into the external pipeline (401) and part flows into the return pipe. The fluid flowing into the return pipe merges with the fluid flowing into the external pipeline (401), forming a flow impact on the rotating valve disc (303) in the butterfly valve assembly (3). The rotating valve disc (303) closes quickly under the impact of the fluid and the rebound of the torsion spring (305); S3. During the closing process of the butterfly valve assembly (3), part of the fluid flows into the valve tube (1) along the gap of the butterfly valve assembly (3). Under the action of the drainage assembly (5), the fluid flowing into the valve tube (1) is gathered, forming an impact force on the moving rod (204) in the opening and closing assembly (2), and with the cooperation of the reset spring (205), the moving valve disc (201) is quickly closed.

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