Gas turbine blade root flaw detection device

Abstract

The invention relates to a gas turbine blade root flaw detection device which comprises a frame body, a probe assembly and a moving device, and the probe assembly comprises a connecting plate, a base arranged below the connecting plate in a sliding mode, a fixing block installed on the base through a pin shaft A and a probe arranged on the fixing block; a spring A used for driving the base to move towards the side close to the blade is arranged on the base, and a spring B is arranged on the pin shaft A and located between the base and the fixing block. The probe transversely moves under the action of the moving device, and through the design of the connecting plate, the base, the fixing block and the corresponding spring, the probe can perform moving detection in the horizontal direction and the vertical direction along with the shape of the blade root in the moving process. The device can be mounted at the first-stage and second-stage blade root parts of a gas turbine compressor side rotor moving blade, performs automatic nondestructive inspection on the blade root in a cylinder combination state, meets regular inspection operation of a power plant, and can effectively perform monitoring and defect prevention on the blade root.

Description

Technical Field

[0001] This invention belongs to the field of gas turbine impeller flaw detection equipment, and specifically relates to a gas turbine blade root flaw detection device. Background Technology

[0002] The first and second stage blades of the gas turbine compressor rotor are the largest diameter blades on the rotor, decreasing in diameter with each subsequent stage. Therefore, these two stages of blades experience the greatest centrifugal force during high-speed operation. Because the blades have concave arcs on both sides of the blade root, after several years of operation, power plants reported that these two stages of blades fractured and failed, severely impacting the unit's normal operation and causing significant economic losses, necessitating cylinder overhaul. Currently, the market uses manual flaw detectors to periodically inspect the blade roots, but this can only inspect the first stage blades. Due to depth limitations, it cannot inspect the second stage blades, and manual inspection cannot guarantee 100% coverage. The low efficiency and pass rate of manual inspection are unacceptable to power plants. Furthermore, inspection can only be scheduled during major overhauls, after the gas turbine is disassembled and the rotor is removed. Regular inspections cannot be performed under cylinder-connected conditions, lacking preventative and controllable capabilities. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a gas turbine blade root flaw detection device, which, after being installed on the blade root, can realize the conformal detection of the convex or concave arc position of the blade root by the probe, with a high degree of automation.

[0004] The technical solution adopted in this invention is: A gas turbine blade root flaw detection device includes a frame, a probe assembly mounted on the frame, and a moving device for moving the probe assembly left and right. The probe assembly includes a connecting plate, a base slidably mounted below the connecting plate, a fixing block mounted on the base via a pin A, and a probe mounted on the fixing block. A spring A is provided on the base for moving it closer to the blade. A spring B is provided on the pin A between the base and the fixing block. The connecting plate is connected to the moving device.

[0005] Furthermore, a dovetail is provided on the bottom surface of the connecting plate, and a corresponding dovetail groove is provided on the base. The two ends of the spring A are respectively installed on the connecting plate and the base.

[0006] Furthermore, pin holes are provided on the left and right sides of the base, and pin A is inserted into the pin holes. The two ends of the fixing block are respectively fixedly connected to the corresponding pin A.

[0007] Furthermore, the moving device includes a rack fixedly mounted on the frame, a slide rail mounted below the rack, a slider mounted on the slide rail, a motor fixedly mounted on the probe assembly, and a gear mounted on the motor output shaft. The gear meshes with the rack, and the connecting plate is fixedly connected to the slider.

[0008] Furthermore, a slide rail is provided on the top surface of the frame, and a hook that cooperates with the slide rail is provided on the top of the connecting plate.

[0009] Furthermore, the frame is clamped at the steam inlet and steam outlet of the blade. A left clamp and a right clamp are provided at the left and right ends of the frame, respectively. The right clamp is a V-groove corresponding to the steam outlet, and the left clamp is a half V-groove. A movable clamp is provided on the left clamp.

[0010] Furthermore, the movable clamp is a semi-V-groove, which together with the left clamp forms a V-groove corresponding to the steam inlet end. The movable clamp is mounted on the frame via pin B. A hook is provided at the lower inner side of the movable clamp, and a tension spring is provided between the hook and the frame.

[0011] Furthermore, a wrench is provided on the outside of the movable clamp.

[0012] Furthermore, support legs are provided at both ends of the frame, and magnets are provided at the bottom of the support legs.

[0013] Furthermore, the outrigger is connected to the frame via a flange, which is an eccentric flange, and its positioning axis is offset from the outrigger axis.

[0014] The positive effects of this invention are: The probe of this invention moves laterally under the action of the moving device. Through the design of the connecting plate, base, fixing block, and corresponding springs, the probe can move horizontally and vertically according to the shape of the blade root during movement, ensuring that the probe is firmly attached to the surface of the blade root mounting groove. This invention can be installed at the blade root of the first and second stage rotor blades on the compressor side of a gas turbine, performing automatic non-destructive testing of the blade root in the cylinder-closed state. This meets the requirements of regular inspection operations in power plants and can effectively monitor and prevent defects in the blade root. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the installation process for flaw detection of convex arc surfaces according to the present invention; Figure 2 For the present invention Figure 1 Diagram of the AA direction; Figure 3 This is a side view of the present invention; Figure 4 For the present invention Figure 3 Diagram of the middle BB direction; Figure 5 This is a top view of the present invention; Figure 6 This is a schematic diagram of the probe assembly structure of the present invention; Figure 7 For the present invention Figure 6 Schematic diagram of the CC direction; Figure 8 This is a schematic diagram of the probe installation position for the present invention; Figure 9 This is a schematic diagram showing the location of the dovetail groove in this invention; Figure 10 This is an assembly diagram of the blades of the present invention; Figure 11 This is a schematic diagram of the installation process for flaw detection of concave arc surfaces according to the present invention. Detailed Implementation

[0016] This invention discloses a gas turbine blade root flaw detection device. Blade 1 is a first-stage and second-stage moving blade on the compressor-side rotor of a gas turbine. The following description of blade root flaw detection refers to these two stages of blades. The first-stage moving blade has a longer length and larger volume than the second-stage moving blade, and these two stages are the largest moving blades on the rotor, bearing the greatest centrifugal force. Blade 1 is installed in the rotor impeller groove, with the blade root flush with the outer circumference of the impeller. Mounting grooves 101 are designed on both the concave and convex surfaces of the blade root. Mounting grooves 101 are weak points of blade 1, and after long-term operation, hidden defects 102 will develop at these locations. That is, defects 102 can occur at any position on either side of the mounting grooves 101 at the blade root of blade 1.

[0017] As attached Figure 1-9 As shown, taking convex arc surface flaw detection as an example, the present invention includes a frame 2 for mounting on a blade 1, a probe assembly set on the frame 2, and a moving device for driving the probe assembly to move left and right.

[0018] The probe assembly includes a semi-open connecting plate 8, a base 9 mounted on the bottom plate of the connecting plate 8, a fixing block 11 mounted on the base 9 via a pin A18, and a probe 7 mounted on the fixing block 11. The bottom plate of the connecting plate 8 faces the blade 1 and has a dovetail 802 on its bottom surface. The surface of the base 9 has a corresponding dovetail groove, and the two are slidably connected. Screws are located on the left and right sides of the base 9 and the bottom plate of the connecting plate 8. A spring A12 is located between the corresponding screws. The spring A12 is a tension spring. Under the action of its tension, the base 9 and the fixing block 11 connected to it move towards the blade root along the front and rear sliding pair formed by the dovetail 802 and the dovetail groove. Pin holes are provided on the left and right sides of the base 9 near the blade 1. A pin A18 is installed in each pin hole, allowing it to slide up and down within the hole. The bottom of pin A18 is fixedly connected to both ends of the fixing block 11. A spring B19 is located on pin A18 between the base 9 and the fixing block 11. Spring B19 is a compression spring that applies a downward force to the fixing block 11, pressing it away from the base 9 and causing it to move downwards towards the blade root. The probe 7 is installed on the side of the fixing block 11 near the blade 1, positioned lower so that it can abut against the blade root under the action of springs A12 and B19. A probe cable is installed on the upper side of the probe 7 for connection to a phased array flaw detector. Preferably, a baffle 10 is provided at the end of the base 9 away from the blade 1 to prevent the base 9 from falling off. After deep clamping, only the probe data cable and the control motor power cable are retained, facilitating on-site disassembly and assembly.

[0019] The probe 7 is mounted within the fixing block 11, allowing it to slide up and down along the sliding joint formed by the base 9 and the fixing block 11 via pin A18, and to be in contact with the blade root in the vertical direction under the pressure of spring B19. Simultaneously, the base 9 slides back and forth along the front-to-back sliding joint formed by dovetail 802 and dovetail groove, and is in contact with the blade root in the front-to-back direction under the tension of spring A12. These two sliding joints enable the probe 7 to be adjustable in both the front-to-back and vertical directions, ensuring that the probe 7 is firmly attached to the surface of the blade root mounting groove 101.

[0020] Because the cross-section of blade 1 is an irregular twisted blade, and the blade root has rounded corners on both the convex and concave surfaces, the distance from these rounded corners to the blade root position changes in real time along the airflow direction. Therefore, the position of probe 7 must have the aforementioned avoidance and adjustability functions in both the vertical and horizontal directions. Based on this, an opening slot 803 is provided in the middle of the bottom plate of connecting plate 8, and the opening slot 803 can effectively avoid the horizontal backward movement trajectory of probe 7, fixing block 11, and base 9 along the dovetail 802 caused by the rounded corners and profile characteristics of the blade root.

[0021] The moving device includes a rack 3 located on the upper outer side of the frame 2, a slide rail 4 located below the rack 3, a slider 17 mounted on the slide rail 4, a motor 13 fixedly mounted on the top plate of the connecting plate 8 of the probe assembly, and a gear mounted on the output shaft of the motor 13. The gear meshes with the rack 3, and the connecting plate 8 is fixedly mounted on the slider 17. The motor 13 drives the gear to rotate, thereby moving the connecting plate 8 left and right along the rack 3, thus realizing the lateral movement of the probe 7. Preferably, a hook 801 is provided at the top end of the connecting plate 8, and a slide rail 203 is provided on the top surface of the frame 2. When the connecting plate 8 moves left and right, the hook 801 slides horizontally along the slide rail 203. Together with the slide rail and the slider, it ensures the stability of the connecting plate 8 during the sliding process.

[0022] The frame 2 of this invention is clamped at both ends of the blade 1, namely the steam inlet end and the steam outlet end. A left clamping opening 201 and a right clamping opening 202 are respectively provided at the left and right ends of the frame 2. The right clamping opening 202 is located at the far end, i.e., inside the rotor, and is designed as a fixed clamping opening, which is V-shaped and engages 100% with the profile 1 of the steam outlet end of the blade 1. The left clamping opening 201 is located at the near end, i.e., outside the rotor, and is designed as an open clamping opening, which is semi-V-shaped and engages 100% with the profile 1 of the steam inlet end of the blade 1. Furthermore, a movable clamping opening 5 is provided on the left clamping opening 201. Its front end is a semi-V-shaped groove that engages 100% with the profile 1 of the steam inlet end of the blade 1, forming a V-groove with the left clamping opening 201 for clamping the steam inlet side of the blade 1. The movable clamping opening 5 is a movable component, fixedly installed at the left end of the frame 2 by a pin B503, meaning the movable clamping opening 5 can rotate around the pin B503 on the frame 2. A hook 502 is provided at the lower end of the movable clamp 5 and on the side close to the blade 1. A positioning pin is provided on the frame 2 at a certain distance from the hook 502. A tension spring 6 is installed between the hook 502 and the positioning pin. The tension spring 6 has a preload force to pull the movable clamp 5 downward. Through the preload force of the tension spring 6, the movable clamp 5 rotates downward around the pin shaft 503 until it is in front and fits against the air inlet end profile of the blade 1, thus forming a movable clamp with the left clamp 201. At the same time, a wrench 501 is provided on the outside of the movable clamp 5.

[0023] During actual installation, first install the right clamp 202 on the steam outlet end of blade 1. Manually press and hold the wrench 501 set on the upper end of the movable clamp 5, and rotate the wrench counterclockwise to open a certain distance. After the left clamp 201 is attached to the steam inlet end of blade 1, release the movable clamp 5. Under the tension of the tension spring 6, the movable clamp 5 rotates clockwise and the front end and the left clamp 201 together clamp the steam inlet end of blade 1.

[0024] Support legs 14 are installed below the frame 2 and between it and the blade root. Two support legs 14 are distributed on the steam inlet and steam outlet sides of the blade 1, and their upper ends are fixedly connected to the frame 2 via flanges 16. Preferably, the flange 16 is an eccentric flange, and its positioning axis is not coaxial with the axis of the support leg 14. That is, the support leg 14 can be arbitrarily positioned on the circumference within the eccentricity between the two axes, ensuring that there is no interference between the support leg 14 and the probe assembly 7 at the steam inlet and steam outlet ends. Magnets 15 are fixedly connected to the lower ends of the support legs 14. Based on the magnetic field effect, the support legs 14 and magnets 15 are attracted to the blade root surface, thereby controlling the installation position of the frame 2 at the height of the blade 1.

[0025] Based on the blade assembly drawing ( Figure 10 The blades 1 are densely distributed around the outer circumference of the rotor, while the blade root portion below the mounting groove 101 is hidden within the rotor body. Therefore, a phased array flaw detector is needed to inspect the mounting groove 101 for hidden defects 102. The device of this invention is compact and can pass between the blades 1, and is secured to the blades 1 via the left clamp 201, right clamp 202, and movable clamp 5. Defects 102 can occur sporadically on either the concave or convex side of the blade 1, so the invention can be installed on both sides of the blade 1 for flaw detection. Because the motor 13 drives the gear to rotate, and the connected probe assembly 7 automatically slides along the length of the mounting groove 101, automated control of the detection is achieved. This enables phased array flaw detection of the blade roots of both the first-stage and second-stage rotor blades, solving the current problems of manual operation being unable to achieve 100% coverage of the first-stage rotor blades and the inability to reach the depth of the second-stage rotor blades for inspection.

[0026] This flaw detection device has a compact structure and is fixedly mounted on blade 1 via a frame. It uses a motor-controlled probe assembly 7 to move along the root of blade 1, achieving automated control. It can perform phased array flaw detection operations on the roots of both first-stage and second-stage moving blades. This solves the problem that traditional manual methods cannot reach the second-stage moving blades for flaw detection. This invention can be designed in two mirror images: one set is installed on the convex side of blade 1 to measure defects at its mounting groove, and the other set is installed on the concave side of the blade to measure defects at its mounting groove (such as...). Figure 11 This ensures 100% coverage of non-destructive testing on both sides of the blades and allows for direct output of the tested images onto the flaw detector. It solves the problem of power plants being unable to perform non-destructive testing on moving blades during shutdown and cylinder operation without major overhauls, effectively achieving controllable detection and prevention of first-stage and second-stage moving blades, thus ensuring the safety of gas turbine operation. This invention is also applicable to online ultrasonic testing of the turbine rotor's last blades in the cylinder-closed state.

Claims

1. A gas turbine blade root flaw detection device, characterized in that... It includes a frame (2), a probe assembly mounted on the frame (2), and a moving device for moving the probe assembly left and right. The probe assembly includes a connecting plate (8), a base (9) slidably mounted below the connecting plate (8), a fixing block (11) mounted on the base (9) via a pin A (18), and a probe (7) mounted on the fixing block (11). A spring A (12) is provided on the base (9) for moving it closer to the blade (1). A spring B (19) is provided on the pin A (18) between the base (9) and the fixing block (11). The connecting plate (8) is connected to the moving device.

2. The gas turbine blade root flaw detection device according to claim 1, characterized in that... A dovetail (802) is provided on the bottom surface of the connecting plate (8), and a corresponding dovetail groove is provided on the base (9). The two ends of the spring A (12) are respectively installed on the connecting plate (8) and the base (9).

3. A gas turbine blade root flaw detection device according to claim 1 or 2, characterized in that... Pin holes are provided on the left and right sides of the base (9), and pin A (18) is inserted into the pin holes. The two ends of the fixing block (11) are fixedly connected to the corresponding pin A (18).

4. The gas turbine blade root flaw detection device according to claim 1, characterized in that... The moving device includes a rack (3) fixedly mounted on the frame (2), a slide rail (4) mounted below the rack (3), a slider (17) mounted on the slide rail (4), a motor (13) fixedly mounted on the probe assembly, and a gear mounted on the output shaft of the motor (13). The gear meshes with the rack (3), and the connecting plate (8) is fixedly connected to the slider (17).

5. A gas turbine blade root flaw detection device according to claim 4, characterized in that... A slide (203) is provided on the top surface of the frame (2), and a hook (801) that cooperates with the slide (203) is provided on the top of the connecting plate (8).

6. The gas turbine blade root flaw detection device according to claim 1, characterized in that... The frame (2) is clamped at the steam inlet and steam outlet of the blade (1). The left clamp (201) and the right clamp (202) are respectively provided at the left and right ends of the frame (2). The right clamp (202) is a V-shaped groove corresponding to the steam outlet, and the left clamp (201) is a half V-shaped groove. A movable clamp (5) is provided on the left clamp (201).

7. A gas turbine blade root flaw detection device according to claim 6, characterized in that... The movable clamp (5) is a semi-V-shaped groove, which together with the left clamp (201) forms a V-shaped groove corresponding to the steam inlet end. The movable clamp (5) is installed on the frame (2) through the pin B (503). A hook (502) is provided at the lower inner side of the movable clamp (5), and a tension spring (6) is provided between the hook (502) and the frame (2).

8. A gas turbine blade root flaw detection device according to claim 7, characterized in that... A wrench (501) is provided on the outside of the movable clamp (5).

9. A gas turbine blade root flaw detection device according to claim 1, characterized in that... Support legs (14) are provided at both ends of the frame (2), and magnets (15) are provided at the bottom of the support legs (14).

10. A gas turbine blade root flaw detection device according to claim 9, characterized in that... The outrigger (14) is connected to the frame (2) via a flange (16), which is an eccentric flange whose positioning axis is offset from the axis of the outrigger (14).

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