A tool and method for extracting a shear pin of a water turbine guide vane

Abstract

The application relates to the field of water turbines, and particularly discloses a tool and method for pulling out a shearing pin of a water turbine guide vane mechanism, which comprises a connecting arm, a screw rod, a support and a jacking mechanism, the lower end of the connecting arm is connected with the screw rod, the upper end of the connecting arm is connected with the jacking end of the jacking mechanism, the fixed end of the jacking mechanism is connected with the support, and the screw rod is matched with the inner hole of the shearing pin. The application can quickly pull out the shearing pin remaining in the crank arm of the guide vane mechanism, improves the shearing pin taking-out efficiency, and reduces the maintenance cost.

Description

Technical Field

[0001] This invention relates to the field of water turbines, specifically a tool and method for removing the shear pin of the water guide mechanism of a water turbine. Background Technology

[0002] The core function of the shear pin is to act as a "mechanical fuse" when the movable guide vanes of the water guiding mechanism are jammed by foreign objects. Its breakage protects the entire water guiding mechanism and other more critical transmission components from damage. For example, when the turbine needs to adjust its power, the governor sends a signal, and the relay drives the control ring to rotate. The control ring, through connecting rods, the shear pin, and the crank arm, drives all movable guide vanes to rotate synchronously and evenly to the specified angle. At this time, the shear pin acts as a robust connecting component, transmitting torque.

[0003] Abnormal state (guide vane jammed): Suppose a foreign object gets stuck between one of the guide vanes. The relay continues to push the control ring, and the other guide vanes rotate normally, but the jammed guide vane cannot move. As the control ring continues to move, the connecting rod connected to the jammed guide vane will experience increasing forces. This force will eventually act entirely on the shear pin connecting the connecting rod and the crank arm. When this force exceeds the design shear pin's shear strength, the shear pin will be precisely sheared. After the shear pin breaks, the jammed guide vane and its crank arm are mechanically disengaged from the control ring and connecting rod. The control ring can continue to drive the other normal guide vanes, and the entire mechanism will not be rendered inoperable or damaged due to one guide vane being jammed.

[0004] When a shear pin breaks, it needs to be replaced immediately. Because the shear pin has a conical shape, it cannot be hammered down; it must be removed from above. The force exerted on the broken shear pin and the clearance make removal difficult. Current removal methods are still simplistic, relying on manual methods like "hammering" and "poking," which makes the replacement process time-consuming, increasing maintenance costs and reducing efficiency. Summary of the Invention

[0005] The purpose of this invention is to provide a tool for removing shear pins from the guide vane mechanism of a water turbine, which can quickly remove pins remaining in the crank arm of the guide vane mechanism, improve the efficiency of removing shear pins, and reduce maintenance costs.

[0006] The objective of this invention can be achieved through the following technical solutions: One aspect of this invention is a tool for pulling out the shear pin of the water guide mechanism of a water turbine, comprising a connecting arm, a screw, a support, and a lifting mechanism. The screw is connected to the lower end of the connecting arm, the upper end of the connecting arm is connected to the lifting end of the lifting mechanism, the fixed end of the lifting mechanism is connected to the support, and the screw matches the inner hole of the shear pin.

[0007] Furthermore, the lifting mechanism includes a hydraulic jack, which is connected to one end of the support. The other end of the support is provided with a clearance groove, and the connecting arm is inserted into the clearance groove.

[0008] Furthermore, the connecting arm is Z-shaped, and both the upper and lower end faces of the Z-shaped connecting arm are provided with through holes. The through hole on the upper end face is connected to the threaded hole on the upper end of the hydraulic jack by bolts, and the through hole on the lower end face is connected to the inner hole of the shear pin by screws.

[0009] Furthermore, a supporting rib is connected to the middle of the connecting arm.

[0010] Furthermore, the lower surfaces of the connecting arm and the support match the upper surface of the crank arm of the water guiding mechanism.

[0011] Furthermore, the upper surface of the crank arm is a plane, and the lower surfaces of the connecting arm and the support are flush planes.

[0012] Furthermore, the supporting stiffener is welded to the connecting arm, and the pressure resisted by the supporting stiffener is greater than the force required to pull out the shear pin.

[0013] Another aspect of the present invention provides a method for removing the shear pin of the water guide mechanism of a water turbine, using the tools described in any of the above solutions, comprising the following steps: Place the connecting arm on the shear pin and pass the screw through the inner hole of the connecting arm and the shear pin; The connecting arm and shear pin are locked by connecting the nut to the screw. Set the support on the crank arm and install the lifting mechanism on the support; The lifting mechanism is controlled to lift the connecting arm, and the connecting arm drives the shear pin to be pulled out from the inner hole of the crank arm.

[0014] Furthermore, the step of the screw passing through the inner hole of the connecting arm and the shear pin includes: Keep the screw and the inner hole of the shear pin coaxial.

[0015] Furthermore, the method for controlling the lifting mechanism to lift the connecting arm includes: A lever is formed between the lifting mechanism and the connecting arm. The near fulcrum end of the lever is connected to the connecting arm. By operating the far fulcrum end of the lever, the connecting arm is lifted.

[0016] The beneficial effects of this invention are: This invention utilizes the central hole of a shear pin. A screw with a diameter similar to the central hole is inserted into the shear pin's central hole. The upper end of the screw is connected to the lifting end of a lifting mechanism via a connecting arm. The lower part of the screw is fixed to the inner hole of the shear pin, subjecting the lower part of the shear pin to an upward axial force. The lifting mechanism and support are positioned on a crank arm. When removing the shear pin, the operator controls the lifting mechanism, similar to pressing a hydraulic jack. The pressure is transmitted to the horizontally rising connecting arm. As the lifting end of the lifting mechanism moves upward, the shear pin is quickly pulled out of the pin hole, significantly improving the efficiency of shear pin removal and reducing maintenance costs. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the connection of the connecting arm in an embodiment of the present invention; Figure 2 This is a schematic diagram of the connecting arm in an embodiment of the present invention; Figure 3 This is a connection diagram of the lifting mechanism in an embodiment of the present invention; Figure 4 This is a schematic diagram of the installation of a tool for pulling out the shear pin of the water turbine guide mechanism in an embodiment of the present invention; Figure 5 A schematic diagram of the steps of a method for pulling out the shear pin of a water turbine guide vane mechanism in an embodiment of the present invention; Figure 6 This is a schematic diagram of the steel bar used in the comparative example of this invention.

[0019] In the diagram: 1. Connecting arm; 2. Screw; 3. Support; 4. Lifting mechanism; 5. Support rib; 6. Crank arm; 7. Through hole; 8. Lifting end; 9. Shear pin. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] like Figure 1As shown, a tool for pulling out the shear pin 9 of the water guide mechanism of a water turbine belongs to the technical field of water turbine maintenance equipment. It mainly solves the problems of existing shear pin 9 pulling tools being cumbersome to operate, time-consuming, and prone to component damage. It includes four core components: a connecting arm 1, a screw 2, a support 3, and a lifting mechanism 4. These components work together to achieve rapid and stable pulling out of the shear pin 9. The screw 2, as shown... Figure 4 As shown, the screw 2 is detachably connected to the lower end of the connecting arm 1 for precise docking with the inner hole of the shear pin 9, thereby fixing the connecting arm 1 and the shear pin 9. The upper end of the connecting arm 1 is fixedly connected to the lifting end 8 of the lifting mechanism 4, which plays a role in force transmission, transferring the lifting force generated by the lifting mechanism 4 to the shear pin 9. The fixed end of the lifting mechanism 4 is stably connected to the support 3, which serves as the supporting foundation for the entire tool, providing a stable force-bearing platform for the lifting mechanism 4. The outer diameter of the screw 2 matches the inner hole diameter of the shear pin 9, ensuring that the coaxiality of the two is up to standard after connection, and avoiding skew during the pull-out process that could cause the shear pin 9 to jam or be damaged.

[0022] In some embodiments, such as Figure 3 As shown, the lifting mechanism 4 preferably uses a hydraulic jack. Hydraulic jacks are characterized by stable output, strong controllability, and large output capacity, making them suitable for removing the shear pin 9 from the turbine's guide vane mechanism under complex conditions such as corrosion and jamming. The hydraulic jack is bolted to one end of the support 3. The other end of the support 3 is provided with a clearance groove that matches the shape of the connecting arm 1. The width and depth of the clearance groove are both greater than the corresponding dimensions of the connecting arm 1, ensuring that the connecting arm 1 can be smoothly inserted into the clearance groove. During the lifting process, the connecting arm 1 can move vertically along the clearance groove, avoiding interference with the support 3. Simultaneously, the inner wall of the clearance groove is smoothed to reduce frictional resistance during the movement of the connecting arm 1, ensuring smooth lifting.

[0023] In some embodiments, such as Figure 2As shown, the connecting arm 1 adopts a Z-shaped structure design, which can effectively adapt to the spatial layout of the crank arm 6 of the turbine guide mechanism, avoid other components on the crank arm 6, and realize the efficient transmission of force between the lifting mechanism 4 and the shear pin 9. The upper and lower end faces of the Z-shaped connecting arm 1 are provided with precision-machined through holes 7. The through hole 7 on the upper end face is fixedly connected to the threaded hole at the upper end of the hydraulic jack by high-strength bolts, ensuring that the connection strength meets the requirements of lifting force transmission and avoiding safety hazards such as falling off or breaking during use; the through hole 7 on the lower end face is fixedly connected to the inner hole of the shear pin 9 by the screw 2. Both ends of the screw 2 are provided with external threads, which are convenient for locking and fixing with nuts. In this embodiment, a 5-ton hydraulic jack is preferably used. This type of jack has a moderate output force, which can meet the force required to pull out the shear pin 9, and is also easy for operators to carry and operate. The lower end face of the support 3 is widened to effectively increase the contact area with the crank arm 6, reduce the pressure of the support 3 on the crank arm 6, and avoid damage to the surface of the crank arm 6. At the same time, the force-bearing end of the support 3 adopts a U-shaped distribution structure to further improve the force stability of the support 3 and prevent the support 3 from overturning during the lifting process.

[0024] In some embodiments, a supporting rib 5 is welded to the middle of the connecting arm 1. The supporting rib 5 is used to enhance the structural strength and deformation resistance of the connecting arm 1, preventing bending, breakage, or other malfunctions when the connecting arm 1 is subjected to lifting force. The supporting rib 5 is preferably made of steel plate of the same material as the connecting arm 1, and its thickness is rationally designed according to the size of the connecting arm 1 and the magnitude of the lifting force, generally not less than 8mm. The supporting rib 5 is welded to the inner bend of the connecting arm 1, forming a reliable welded connection with both the upper and lower end faces of the connecting arm 1. The weld seam adopts a continuous full welding process to ensure welding strength. Furthermore, the pressure resistance of the supporting rib 5 is precisely calculated, and its rated pressure resistance is greater than the maximum force required to pull out the shear pin 9, structurally ensuring the safety and reliability of the tool.

[0025] In some embodiments, the lower surfaces of the connecting arm 1 and the support 3 match the upper surface of the crank arm 6 of the water guiding mechanism. This design ensures surface contact between the connecting arm 1 and the support 3 and the crank arm 6, avoiding localized stress concentration caused by point or line contact, and protecting the crank arm 6 and the tool itself. Specifically, if the upper surface of the crank arm 6 is a flat plane, the lower surfaces of the connecting arm 1 and the support 3 are machined into flush planes, allowing for uniform force distribution after they are fitted together. If the upper surface of the crank arm 6 is an arc or other irregular shape, the lower surfaces of the connecting arm 1 and the support 3 are correspondingly machined into matching arc or irregular shapes to ensure a tight fit and improve support stability.

[0026] In one specific structural embodiment, the Z-shaped connecting arm 1 is mainly welded from a 10mm thick high-quality steel plate, balancing structural strength and lightweight requirements, facilitating handling and installation by operators. The upper part of the connecting arm 1, which contacts the top of the jack, uses a 14mm thick reinforced steel plate to further enhance the compressive strength of this stressed part and prevent dents and deformation after long-term use. A 12mm diameter through hole 7 is provided in the middle of the upper end, precisely corresponding to the threaded hole at the upper end of the hydraulic jack, for securing the connecting arm 1 to the hydraulic jack with high-strength bolts; a 12mm diameter through hole 7 is also provided on the lower end face for inserting the screw 2 to achieve a fixed connection with the shear pin 9. The supporting rib plate 5 in the middle of the connecting arm 1 is reinforced by welding to the upper and lower end faces, with a weld width of not less than 5mm. Multi-layer welding enhances the structural strength of the welded parts, ensuring that the connecting arm 1 will not deform or break under maximum lifting force.

[0027] like Figure 5 As shown, this invention also proposes a method embodiment for pulling out the shear pin 9 of the water guide mechanism of a water turbine. This method is based on the tool described in any of the above embodiments, is simple and convenient to operate, and can effectively shorten the time for pulling out the shear pin 9 and improve maintenance efficiency. Specifically, it includes the following steps: First, place the connecting arm 1 above the shear pin 9 to be pulled out, and adjust the position of the connecting arm 1 so that the through hole 7 on the lower end face of the connecting arm 1 is precisely aligned with the inner hole of the shear pin 9. Then, pass the screw 2 through the through hole 7 on the lower end face of the connecting arm 1 and the inner hole of the shear pin 9 in sequence, ensuring that the screw 2 and the inner hole of the shear pin 9 remain coaxial, to avoid damage to the inner hole of the shear pin 9 or difficulty in subsequent pull-out due to the screw 2 being misaligned. During the process of passing the screw 2 through, auxiliary positioning tools can be used to further improve the coaxiality accuracy, laying the foundation for subsequent operations.

[0028] The second step involves connecting the nut to the external thread of the screw 2, tightening the nut to the lower end face of the connecting arm 1 to securely lock the connecting arm 1 and the shear pin 9, ensuring no relative slippage between them and guaranteeing that the lifting force can be effectively transmitted to the shear pin 9. A wrench can be used to tighten the nut, controlling the torque to prevent excessive torque from damaging the screw 2 or the shear pin 9, while also preventing insufficient torque from causing the connection to loosen.

[0029] Third, place the support 3 stably on the crank arm 6 of the water guiding mechanism, adjust the position of the support 3 so that the clearance groove on the support 3 is precisely aligned with the connecting arm 1, and ensure that the connecting arm 1 can be smoothly inserted into the clearance groove. Then, install the lifting mechanism 4 in the preset position of the support 3, and firmly connect the fixed end of the lifting mechanism 4 to the support 3 with bolts. Check the installation status of the lifting mechanism 4 to ensure that it is in a horizontal and stable state, and avoid tilting during the lifting process.

[0030] The fourth step involves starting the lifting mechanism 4, causing its lifting end 8 to lift the connecting arm 1 upwards. Under the lifting force, the connecting arm 1 moves vertically upwards along the clearance groove, which in turn drives the shear pin 9 to move upwards synchronously via the screw 2, ultimately pulling the shear pin 9 smoothly out of the inner hole of the crank arm 6. During the lifting process, the operator must operate the lifting mechanism 4 slowly and observe the pulling status of the shear pin 9 in real time. If jamming occurs, the lifting should be stopped immediately, the problem investigated and resolved before continuing the operation, to avoid forcibly lifting and causing the shear pin 9 to break or the crank arm 6 to be damaged.

[0031] In some embodiments, the method for controlling the lifting mechanism 4 to lift the connecting arm 1 can also employ a lever-assisted approach. A lever structure is installed between the lifting mechanism 4 and the connecting arm 1, with the near-fulcrum end of the lever fixedly connected to the connecting arm 1 and the far-fulcrum end accessible to the operator. This leverage principle amplifies the lifting force, further reducing the operator's workload, and is particularly suitable for situations where the shear pin 9 is severely jammed and faces significant resistance during removal. The operator presses down on the far-fulcrum end of the lever, utilizing the lever's force-saving effect to move the connecting arm 1 upwards, thus removing the shear pin 9. Figure 5 The medium-width arrows clearly indicate the installation steps and force transmission direction of each component of the tool, making it easy for operators to quickly understand and master the installation process.

[0032] In a specific usage example, such as Figure 4 As shown, when the shear pin 9 of the turbine guide vane mechanism breaks and needs to be removed and replaced, the specific operating procedure is as follows: First, connect the 5-ton hydraulic jack to the Z-type connecting arm 1 with high-strength bolts to ensure a firm connection; then, place the entire hydraulic puller stably above the shear pin 9 to be removed, adjust the position so that the through hole 7 at the lower end of the connecting arm 1 is aligned with the inner hole of the shear pin 9, fix the lower end of the Z-type connecting arm 1 to the shear pin 9 with the screw 2, and tighten the nut to lock it in place; next, check the fit between the support 3 and the crank arm 6 and the installation status of the lifting mechanism 4. After confirming that everything is correct, operate the operating handle of the hydraulic jack evenly and stably, so that the output shaft of the jack slowly extends upward, driving the Z-type connecting arm 1 to move upward. Through the stable transmission of force, the shear pin 9 is smoothly pulled out from the inner hole of the crank arm 6. The entire process is simple to operate, requires no multiple people to cooperate, and can be completed by a single person. The time for installing and using the tool to pull out the shear pin 9 can be greatly shortened. After actual testing, after simple training, general operators can complete the operation of pulling out a single shear pin 9 within 10 minutes, which effectively improves the efficiency of turbine maintenance and reduces unit downtime.

[0033] To further highlight the advantages of the tool proposed in this application, a comparative example is provided below, such as... Figure 6As shown, the commonly used tool for pulling out the shear pin 9 in the prior art is a puller steel bar, which has a relatively simple structure. It mainly includes a puller steel bar, a nut, a sliding pad, and a sliding hammer. The lower end of the puller steel bar is provided with an external thread, which can be matched with the internal thread of the shear pin 9. The nut is screwed onto the lower end of the puller steel bar, and a sliding pad is fitted on the upper end of the nut. A stop is fixed on the upper end of the steel bar, and a sliding sliding hammer is fitted on the steel bar between the stop and the pad. Handles are provided on both sides of the sliding hammer for easy gripping and operation by the operator.

[0034] The working principle of the existing tool is as follows: The sliding hammer is inserted into the steel bar, and the threaded side of the steel bar is inserted into the central hole of the shear pin 9, ensuring a secure threaded connection between the steel bar and the shear pin 9. Then, a sliding pad to protect the crank arm 6 is placed under the shear pin 9. Finally, the nut at the lower end of the steel bar is tightened to ensure the pad is in contact with the surface of the crank arm 6. The operator holds the handles on both sides of the sliding hammer with both hands and repeatedly pulls the hammer upwards, causing it to move rapidly upwards along the steel bar. The impact inertia of the upward movement of the sliding hammer generates an impact force on the stop body, which is then transmitted to the shear pin 9 through the steel bar. This impact force pulls the shear pin 9 out of the pin hole of the guide vane crank arm 6.

[0035] However, existing tools have many drawbacks in practical use: First, they are cumbersome to operate, requiring multiple people to pull the pendulum, resulting in high labor intensity; second, the impact force is uncontrollable, as the impact inertia of the pendulum is difficult to control precisely. Insufficient impact force cannot remove the shear pin 9, while excessive force can easily cause the shear pin 9 to break, damage the pin hole of the crank arm 6, or even injure the operator; third, the work efficiency is extremely low. Actual testing showed that using existing pullers and steel bars to remove a single shear pin 9 takes an average of 62 minutes, far from meeting the needs of rapid turbine maintenance and quick restoration of unit operation. In contrast, the shear pin 9 removal tool and method of this application achieves stable force output through hydraulic jacking, is simple to operate, and highly controllable. It effectively protects the shear pin 9 and crank arm 6 while significantly shortening maintenance time, demonstrating significant technical advantages and practical value.

[0036] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0037] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A tool for pulling out the shear pin of the water guide mechanism of a water turbine, characterized in that, It includes a connecting arm (1), a screw (2), a support (3) and a lifting mechanism (4). The screw (2) is connected to the lower end of the connecting arm (1), the upper end of the connecting arm (1) is connected to the lifting end (8) of the lifting mechanism (4), the fixed end of the lifting mechanism (4) is connected to the support (3), and the screw (2) matches the inner hole of the shear pin (9).

2. A tool for pulling out the shear pin of a water turbine guide vane mechanism according to claim 1, characterized in that, The lifting mechanism (4) includes a hydraulic jack, which is connected to one end of the support (3). The other end of the support (3) is provided with a clearance groove, and the connecting arm (1) is inserted into the clearance groove.

3. A tool for pulling out the shear pin of a water turbine guide vane mechanism according to claim 2, characterized in that, The connecting arm (1) is Z-shaped. The upper and lower end faces of the Z-shaped connecting arm (1) are provided with through holes (7). The through hole (7) on the upper end face is connected to the threaded hole on the upper end of the hydraulic jack by bolts. The through hole (7) on the lower end face is connected to the inner hole of the shear pin (9) by the screw (2).

4. A tool for pulling out the shear pin of a water turbine guide vane mechanism according to claim 3, characterized in that, The connecting arm (1) is connected to a supporting rib plate (5) in the middle.

5. A tool for pulling out the shear pin of a water turbine guide vane mechanism according to claim 3, characterized in that, The lower surfaces of the connecting arm (1) and the support (3) match the upper surface of the crank arm (6) of the water guiding mechanism.

6. A tool for pulling out the shear pin of a water turbine guide vane mechanism according to claim 5, characterized in that, The upper surface of the crank arm (6) is a plane, and the lower surfaces of the connecting arm (1) and the support (3) are flush planes.

7. A tool for pulling out the shear pin of a water turbine guide vane mechanism according to claim 4, characterized in that, The supporting stiffener (5) is welded to the connecting arm (1), and the pressure resisted by the supporting stiffener (5) is greater than the force required to pull out the shear pin (9).

8. A method for removing the shear pin of a water turbine guide vane mechanism, characterized in that, Using the tool according to any one of claims 1-7 includes the following steps: Place the connecting arm (1) on the shear pin (9) and make the screw (2) pass through the inner hole of the connecting arm (1) and the shear pin (9); The connecting arm (1) and the shear pin (9) are locked by connecting the nut to the screw (2); Set the support (3) on the crank arm (6) and install the lifting mechanism (4) on the support (3); Control the lifting mechanism (4) to lift the connecting arm (1), and drive the shear pin (9) to be pulled out from the inner hole of the crank arm (6) through the connecting arm (1).

9. A method for removing the shear pin of a turbine guide vane mechanism according to claim 8, characterized in that, The steps of the screw (2) passing through the inner hole of the connecting arm (1) and the shear pin (9) include: Keep the screw (2) coaxial with the inner hole of the shear pin (9).

10. A method for removing the shear pin of a water turbine guide vane mechanism according to claim 8, characterized in that, The method for controlling the lifting mechanism (4) to lift the connecting arm (1) includes: A lever is formed between the lifting mechanism (4) and the connecting arm (1). The near fulcrum end of the lever is connected to the connecting arm (1). The connecting arm (1) is lifted by operating the far fulcrum end of the lever.

Images