Large-pitch hand-operated flat gate valve

Abstract

The application discloses a large-passage manual flat gate valve and belongs to the technical field of valves.The valve body is provided with a through port, and the two sides are respectively provided with an inlet end and an outlet end; the bypass pipe is connected between the inlet end and the outlet end, and a needle valve is installed on the bypass pipe; the gate is slidably arranged in the valve cavity and is provided with a valve port; the driving rod is threadedly arranged on the gate through a self-lubricating bushing; the screwing assembly is arranged at the outer end of the valve body and is in transmission connection with the driving rod, and comprises three-stage meshing gears with gradually increasing diameters; and a small angle rotation of the hand wheel can drive the driving rod to rapidly rotate to switch the communication or cut-off of the valve port and the through port. The application balances the pressure difference through the bypass pipe to reduce the torque, uses the three-stage gear to increase the speed to shorten the operation time, and uses the self-lubricating bushing to prevent rust and jam caused by long-term inaction, and has the advantages of labor-saving, quick operation and high reliability.

Description

Technical Field

[0001] This invention relates to the field of valve technology, specifically to a large-diameter manual flat gate valve. Background Technology

[0002] In oil and gas fracturing operations, fracturing manifold systems typically include multiple high-pressure channels. Each high-pressure channel is generally equipped with a large-diameter manual flat gate valve as an emergency backup valve, which is manually shut off or adjusted in case of control system failure or equipment maintenance. This gate valve is kept fully open most of the time and only needs to be closed in emergency situations.

[0003] Currently, large-diameter manual flat gate valves used in high-pressure fracturing operations have the following technical defects in practical applications: Manually opening and closing the gate valve under high pressure differential conditions requires extremely high torque, making operation difficult. During fracturing operations, the pressure inside the pipeline typically exceeds 70 MPa. When closing the gate valve, a huge pressure difference exists on both sides of the gate, and the high-pressure fluid presses the gate tightly against the valve seat, generating immense friction. The torque applied by the operator using the handwheel needs to overcome hundreds to thousands of Newton-meters of static friction torque, making the closing operation impossible with ordinary human strength. Even with a lever, it is difficult to quickly close the gate valve in emergencies, resulting in poor reliability of the emergency shut-off function.

[0004] The long opening and closing strokes and time-consuming operation of large-diameter manual gate valves fail to meet the timeliness requirements of emergency response. Large-diameter manual gate valves typically have a diameter of 4 inches or more, requiring dozens or even hundreds of handwheel rotations to fully open or close the gate. During fracturing operations, in emergency situations such as pipeline overpressure or leakage, the shut-off operation must be completed within seconds to tens of seconds. Manually operating large-diameter gate valves requires several minutes of continuous rotation, which is completely unacceptable for rapid response in emergencies. Delays in emergency handling may lead to equipment damage or personal injury.

[0005] Gate valves that remain fully open for extended periods without operation are prone to corrosion and jamming of the valve stem threads and guide parts due to the high humidity and dust conditions at fracturing sites. The harsh environment of fracturing operations allows moisture and dust in the air to easily penetrate the gap between the valve stem and the stuffing box, as well as the threaded mating surfaces. Gate valves that have been idle for a long time are susceptible to accumulating dirt and corrosion on their valve stem threads and guide parts. When an emergency shutdown is required, the jamming resistance caused by corrosion and dirt, combined with the high pressure differential, renders the gate valve completely unable to operate, thus losing its emergency shut-off function.

[0006] The lack of a self-lubricating structure makes maintenance inconvenient. Conventional manual flat gate valves involve direct metal-to-metal contact sliding between the valve stem and gate, and between the gate and valve cavity, lacking an effective lubrication system. To maintain smooth valve operation, regular manual grease injection is required. However, gate valves in fracturing operations are typically installed on pipe assembly skids, a compact location that makes grease injection difficult and maintenance inconvenient. Summary of the Invention

[0007] The purpose of this invention is to provide a large-diameter manual flat gate valve to solve the technical problems of existing manual flat gate valves, such as large opening and closing torque under high pressure differential, long operation time, easy corrosion and jamming, and lack of self-lubricating structure.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A large-diameter manual flat gate valve, comprising: The valve body has an opening, and the valve body has an inlet and an outlet on both sides that communicate with the opening. A bypass pipe is connected between the inlet and the outlet. The inner diameter of the bypass pipe is smaller than the inner diameter of the port. A needle valve is installed on the bypass pipe. A valve cavity is formed within the valve body, and a gate is slidably disposed within the valve cavity, with a valve port formed on the gate. A drive rod is threaded through the gate plate, with one end of the drive rod rotatably disposed in the valve body and the other end rotatably extending out of the valve body. A rotating assembly is disposed at the outer end of the valve body and is connected to the extended end of the drive rod for driving the drive rod to rotate, thereby moving the gate within the valve cavity to switch the connection or disconnection between the valve port and the through port.

[0009] A further technical solution is that a first self-lubricating bushing is provided between the gate and the drive rod.

[0010] A further technical solution is that a second self-lubricating bushing is provided between the gate and the valve cavity, and the second self-lubricating bushing is slidably sleeved on the guide rod fixed in the valve cavity.

[0011] A further technical solution is that the turning assembly includes a first gear, a second gear, and a third gear with successively increasing diameters; the first gear is coaxially fixed to the outer end of the drive rod, the second gear is rotatably mounted on the outer end of the valve body and meshes with the first gear, and the third gear is rotatably mounted on the outer end of the valve body and meshes with the second gear; a handwheel is coaxially fixed on the third gear.

[0012] A further technical solution is that an oil injection hole extending into the valve cavity is provided on the outer side of the valve body, and a plug is detachably provided on the oil injection hole; an oil inlet groove is provided on the side wall of the gate, and the oil inlet groove passes through one end of the gate near the oil injection hole.

[0013] A further technical solution is that the oil inlet grooves near both sides of the valve port are U-shaped.

[0014] A further technical solution is that the bypass pipe is a V-shaped pipe, and the needle valve is installed at the bend of the V-shaped pipe.

[0015] A further technical solution is that the outer end of the valve body is fitted with a housing for shielding the turning assembly.

[0016] A further technical solution is that the ports of the inlet and the outlet are respectively equipped with flanges.

[0017] A further technical solution is that the first self-lubricating bushing and the second self-lubricating bushing are made of graphite-filled copper alloy or polytetrafluoroethylene composite material.

[0018] Compared with the prior art, the beneficial effects of the present invention are: By setting up a bypass pipe and needle valve connecting the inlet and outlet, the needle valve is opened before closing the main gate valve to allow the high-pressure fluid on both sides of the gate valve to slowly balance through the bypass pipe. After the pressure difference is reduced, the main gate valve is closed, which greatly reduces the opening and closing torque under high pressure difference. Operators can easily complete the closing operation without the need for a lever.

[0019] The three-stage gear speed-increasing transmission of the turning assembly allows the handwheel to rotate at a small angle, which drives the drive rod to rotate at a large angle quickly. This significantly shortens the operation time required for the full stroke of the gate valve to open and close, meeting the rapid response requirements in emergency situations.

[0020] The self-lubricating function without external grease injection is achieved by using the first self-lubricating bushing between the gate and the drive rod and the second self-lubricating bushing between the gate and the guide rod. This effectively prevents the threaded mating surfaces and sliding mating surfaces from rusting and jamming due to long-term inactivity, while also reducing the frequency and difficulty of maintenance.

[0021] Through the lubrication structure of the oil injection hole and the oil inlet groove on the side wall of the gate, lubricating oil can be injected into the valve cavity periodically. The lubricating oil is evenly distributed on each sliding contact surface through the oil inlet groove, forming an oil film protection, which further enhances the rust prevention capability.

[0022] The U-shaped oil inlet groove design prevents the oil inlet groove from directly extending to the edge of the valve port, thus preventing lubricating oil from leaking from the valve port into the fluid channel and contaminating the medium. Attached Figure Description

[0023] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the following figures are provided for illustration: Figure 1 This is a three-dimensional diagram of the large-diameter manual flat gate valve of the present invention.

[0024] Figure 2 This is a three-dimensional view of the valve body in the large-diameter manual flat gate valve of the present invention.

[0025] Figure 3 This is a three-dimensional diagram of the turning assembly in the large-diameter manual flat gate valve of the present invention.

[0026] Figure 4 This is a longitudinal sectional view of the large-diameter manual flat gate valve of the present invention.

[0027] Figure 5 This is a three-dimensional view of the valve plate in the large-diameter manual flat gate valve of the present invention.

[0028] Icons: 61-Valve body, 611-Port, 612-Inlet, 613-Outlet, 614-Flange, 615-Drive slot, 616-Oil inlet, 617-Plug, 62-Bypass pipe, 621-Needle valve, 63-Valve cavity, 64-Gate, 641-Valve port, 642-Oil inlet, 65-Drive rod, 66-Turning assembly, 661-First gear, 662-Second gear, 663-Third gear, 664-Driven shaft, 665-Drive shaft, 666-Extending column, 667-Handwheel, 67-Guide rod, 68-Housing housing. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0030] Example 1 like Figures 1 to 5 As shown, the present invention provides a large-diameter manual flat gate valve, which includes a valve body 61, a bypass pipe 62, a valve cavity 63, a gate plate 64, a drive rod 65, and a turning assembly 66.

[0031] The valve body 61 has a port 611, and on both sides of the valve body 61 are an inlet end 612 and an outlet end 613 communicating with the port 611, respectively. The inlet end 612 and the outlet end 613 are each equipped with a flange 614 for easy connection and installation with high-pressure pipeline flanges. The flange 614 has bolt holes, allowing for fastening to the pipeline flange with bolts to achieve sealing and fixation.

[0032] A bypass pipe 62 is connected between the inlet end 612 and the outlet end 613, and the inner diameter of the bypass pipe 62 is much smaller than the inner diameter of the port 611. A needle valve 621 is installed on the bypass pipe 62. In this embodiment, the bypass pipe 62 is a V-shaped pipe, with its two ends connected to the inlet end 612 and the outlet end 613 respectively, and the needle valve 621 is installed at the bend in the middle. The V-shaped structure facilitates the smooth flow of high-pressure fluid into the bypass pipe, reducing flow resistance, while the bend facilitates the installation and operation of the needle valve.

[0033] A valve chamber 63 is located within the valve body 61, and a gate 64 is slidably mounted within the valve chamber 63 perpendicular to the fluid direction (i.e., vertical direction). A valve port 641 is provided on the gate 64. When the gate 64 moves until the valve port 641 aligns with the through port 611, the gate valve is fully open, allowing high-pressure fluid to flow from the inlet 612 through the through port 611 and the valve port 641 to the outlet 613. When the gate 64 moves until the valve port 641 deviates from the through port 611, the solid portion of the gate 64 blocks the through port 611, and the gate valve is closed.

[0034] The drive rod 65 is threaded onto the gate plate 64. Specifically, the gate plate 64 has an internally threaded hole in which a first self-lubricating bushing 651 is embedded. The outer circumference of the drive rod 65 has an external thread that mates with the internal thread of the first self-lubricating bushing 651. The drive rod 65 is threadedly connected to the gate plate 64 through the first self-lubricating bushing 651. One end of the drive rod 65 is rotatably disposed within a drive groove 615 opened in the valve body 61, and the other end rotatably extends out of the valve body 61. The axial direction of the drive rod 65 is parallel to the direction of movement of the gate plate 64 (i.e., the vertical direction). When the drive rod 65 rotates, the threaded engagement drives the gate plate 64 to reciprocate along the axial direction of the drive rod 65. The first self-lubricating bushing 651 is made of graphite-filled copper alloy or polytetrafluoroethylene composite material. It forms a friction-reducing layer between the drive rod 65 and the gate 64, preventing the threads of the drive rod 65 from directly contacting the internal threaded hole of the gate 64 and causing seizing or wear. At the same time, even if it is not used for a long time, the self-lubricating bushing can ensure that the threaded mating surface will not get stuck due to rust.

[0035] A guide rod 67 is also fixed inside the valve cavity 63. The guide rod 67 is vertically fixed inside the valve cavity 63 and arranged parallel to the drive rod 65. The guide rod 67 slides through the gate 64, guiding the movement of the gate 64 and ensuring that the gate 64 moves in a straight line, preventing deflection or jamming due to thread fit errors. Specifically, the gate 64 has a guide hole for the guide rod 67 to pass through. A second self-lubricating bushing 671 is embedded in the guide hole. The guide rod 67 passes through the second self-lubricating bushing 671 and slides in contact with the inner wall of the second self-lubricating bushing 671. The second self-lubricating bushing 671 is made of the same self-lubricating material as the first self-lubricating bushing 651. The second self-lubricating bushing 671 transforms the sliding friction between the guide rod 67 and the gate 64 into self-lubricating sliding. Even if it does not move for a long time in a high-humidity and dusty environment, it will not cause guide jamming due to corrosion, ensuring that the gate 64 can always slide smoothly.

[0036] A turning assembly 66 is disposed at the outer end of the valve body 61 and is connected to the extended end of the drive rod 65 for transmission. The turning assembly 66 includes a first gear 661, a second gear 662, and a third gear 663 with progressively increasing diameters. The first gear 661 is coaxially fixed to the outer circumference of the drive rod 65 extending from the outer end of the valve body 61. The second gear 662 is rotatably mounted on the outer end of the valve body 61 via a driven shaft 664, and the second gear 662 meshes with the first gear 661. The third gear 663 is rotatably mounted on the outer end of the valve body 61 via a drive shaft 665, and the third gear 663 meshes with the second gear 662. An extended post 666 is coaxially fixed on the drive shaft 665, and a handwheel 667 is mounted on the extended post 666.

[0037] When the operator turns handwheel 667, handwheel 667 drives the extension column 666 and drive shaft 665 to rotate. The third gear 663 on drive shaft 665 rotates accordingly, driving the meshing second gear 662 to rotate. The second gear 662 then drives the first gear 661 to rotate, and the first gear 661 drives the drive rod 65 to rotate. Since the diameters of the first gear 661, second gear 662, and third gear 663 increase sequentially (i.e., the diameter of the third gear 663 > the diameter of the second gear 662 > the diameter of the first gear 661), the large gear on the handwheel 667 side drives the small gear on the drive rod side, achieving speed-increasing transmission. Through a reasonable transmission ratio design (e.g., the number of teeth of the first gear: the number of teeth of the second gear: the number of teeth of the third gear = 1:3:9), a small rotation of handwheel 667 can drive the drive rod 65 to rotate quickly by a large angle, shortening the operation time.

[0038] Preferably, a housing 68 for shielding the turning assembly 66 is installed on the outer end of the valve body 61, and the handwheel 667 is located outside the housing 68. The housing 68 provides dustproof, waterproof, and impact-resistant protection for the turning assembly 66, improving its reliability in the harsh environment of the fracturing site. The housing 68 can be detachably installed on the outer end face of the valve body 61 by bolts.

[0039] In this embodiment, an oil injection hole 616 extending into the valve cavity 63 is also provided on the outer side of the valve body 61, and a plug 617 is detachably provided on the oil injection hole 616. The plug 617 can be threaded to the oil injection hole 616 to achieve a seal. During periodic maintenance, the operator pulls out the plug 617 and injects lubricating oil or grease into the valve cavity 63 through the oil injection hole 616. The four side walls of the gate 64 parallel to the length direction of the drive rod 65 are provided with oil inlet grooves 642, and the oil inlet grooves 642 penetrate through one end of the gate 64 near the oil injection hole 616 (i.e., the upper end of the gate 64). The injected lubricating oil is evenly distributed along the oil inlet grooves 642 under the action of gravity on the sliding contact surface between the gate 64 and the valve cavity 63 and the threaded part of the drive rod 65, forming an oil film protection, effectively preventing rust and jamming caused by long-term inactivity.

[0040] Furthermore, the oil inlet grooves 642 on both sides near the valve port 641 are U-shaped, that is, the oil inlet grooves 642 bend and wind around the edge near the valve port 641, so as to prevent the oil inlet grooves 642 from directly penetrating to the edge of the valve port 641, thereby preventing lubricating oil from leaking from the valve port 641 into the fluid channel and contaminating the medium.

[0041] The working process of the large-diameter manual flat gate valve in this embodiment is as follows: During normal fracturing operations, the gate valve 64 is in the fully open position (valve port 641 is aligned with through port 611), and the high-pressure fluid flows from the inlet 612 through through port 611 and valve port 641 to the outlet 613. At this time, the needle valve 621 remains closed, and the bypass pipe 62 does not participate in the fluid flow.

[0042] When an emergency shut-off of the pipeline is required, the operator first opens the needle valve 621, connecting the inlet 612 and the outlet 613 through the bypass pipe 62. Since the inner diameter of the bypass pipe 62 is much smaller than the inner diameter of the port 611, the fluid flows slowly through the bypass pipe 62, gradually bringing the high-pressure fluid on both sides of the gate 64 to a pressure equilibrium. Once the pressure difference on both sides of the gate 64 has decreased to a safe range, the operator turns the handwheel 667. The handwheel 667, through a three-stage gear speed-increasing transmission (third gear 663, second gear 662, first gear 661), drives the drive rod 65 to rotate rapidly, causing the gate 64 to move downwards along the guide rod 67, causing the valve port 641 to deviate from the port 611. The solid part of the gate 64 blocks the port 611, completing the gate valve closure. Because the pressure on both sides of the gate is basically balanced before closure, the friction between the gate 64 and the valve seat is greatly reduced, and the handwheel operating torque is significantly reduced, allowing the operator to easily complete the closure without the need for a lever.

[0043] When the gate valve needs to be reopened, the operator turns the handwheel 667 in the opposite direction, driving the gate plate 64 to move in the opposite direction (upward) until the valve port 641 and the through port 611 are realigned, the gate valve returns to the fully open state, and then the needle valve 621 is closed to resume normal operation.

[0044] During regular maintenance, the operator pulls out the plunger 617 and injects lubricating oil into the valve chamber 63 through the oil injection hole 616. The lubricating oil is evenly distributed to each sliding contact surface through the oil inlet groove 642. Then, the plunger 617 is pushed back in to complete the lubrication maintenance.

[0045] This invention solves the problem of extremely high manual opening and closing torque under high pressure differential by using the balanced structure of the bypass pipe 62 and the needle valve 621; it solves the problem of long opening and closing strokes and time-consuming operation of large-diameter gate valves by using the three-stage gear speed-increasing transmission of the turning assembly 66; it achieves self-lubrication function through the first self-lubricating bushing 651 and the second self-lubricating bushing 671, solving the problem of rust and jamming of threads and sliding surfaces caused by long-term inactivity; and it further enhances rust prevention and reduces maintenance difficulty through the supplementary lubrication structure of the oil injection hole 616 and the oil inlet groove 642. The improved large-diameter manual flat gate valve, as an emergency backup valve, can quickly and reliably complete the shut-off function in emergency situations.

[0046] Although the invention has been described herein with reference to several illustrative embodiments, it should be understood that many other modifications and implementations can be devised by those skilled in the art, which will fall within the scope and spirit of the principles disclosed herein. More specifically, various variations and modifications can be made to the components and / or layout of the subject matter arrangement within the scope of the disclosure, drawings, and claims. Besides variations and modifications to the components and / or layout, other uses will be apparent to those skilled in the art.

Claims

1. A large-diameter manual flat gate valve, characterized in that: include: The valve body has an opening, and the valve body has an inlet and an outlet on both sides that communicate with the opening. A bypass pipe is connected between the inlet and the outlet. The inner diameter of the bypass pipe is smaller than the inner diameter of the port. A needle valve is installed on the bypass pipe. A valve cavity is formed within the valve body, and a gate is slidably disposed within the valve cavity, with a valve port formed on the gate. A drive rod is threaded through the gate plate, with one end of the drive rod rotatably disposed in the valve body and the other end rotatably extending out of the valve body. A rotating assembly is disposed at the outer end of the valve body and is connected to the extended end of the drive rod for driving the drive rod to rotate, thereby moving the gate within the valve cavity to switch the connection or disconnection between the valve port and the through port.

2. The large-diameter manual flat gate valve according to claim 1, characterized in that: A first self-lubricating bushing is provided between the gate and the drive rod.

3. A large-diameter manual flat gate valve according to claim 2, characterized in that: A second self-lubricating bushing is provided between the gate and the valve cavity, and the second self-lubricating bushing is slidably sleeved on the guide rod fixed in the valve cavity.

4. A large-diameter manual flat gate valve according to claim 1, characterized in that: The turning assembly includes a first gear, a second gear, and a third gear with successively increasing diameters; the first gear is coaxially fixed to the outer end of the drive rod, the second gear is rotatably mounted on the outer end of the valve body and meshes with the first gear, and the third gear is rotatably mounted on the outer end of the valve body and meshes with the second gear; a handwheel is coaxially fixed on the third gear.

5. A large-diameter manual flat gate valve according to claim 1, characterized in that: The valve body has an oil injection hole extending into the valve cavity on its outer side, and a plug is detachably provided on the oil injection hole; the gate plate has an oil inlet groove on its side wall, and the oil inlet groove passes through one end of the gate plate near the oil injection hole.

6. A large-diameter manual flat gate valve according to claim 5, characterized in that: The oil inlet grooves near both sides of the valve port are U-shaped.

7. A large-diameter manual flat gate valve according to claim 1, characterized in that: The bypass pipe is a V-shaped pipe, and the needle valve is installed at the bend of the V-shaped pipe.

8. A large-diameter manual flat gate valve according to claim 1, characterized in that: The outer end of the valve body is fitted with a housing for shielding the turning assembly.

9. A large-diameter manual flat gate valve according to claim 1, characterized in that: The inlet and outlet ports are each equipped with a flange.

10. A large-diameter manual flat gate valve according to claim 3, characterized in that: The first self-lubricating bushing and the second self-lubricating bushing are made of graphite-filled copper alloy or polytetrafluoroethylene composite material.

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