Moving blade vibration frequency testing mechanism based on steam turbine

Abstract

The utility model discloses a moving blade vibration frequency testing mechanism based on a steam turbine, and relates to the technical field of blade vibration frequency testing. Comprising a test support, the test support is internally and rotatably connected with a test shaft, during testing, a piston rod stretches out and draws back through work of a piston seat and an air cylinder, and then pushing contraction work on a supporting block is achieved; the supporting plates and the supporting blocks form a rotating structure through the second rotating shafts, the connecting rods and the first rotating shafts, the distance between the supporting plates on the two sides is shrunk, the rotor base is clamped, the force for clamping the rotor base can be more accurate, and therefore the stability and safety of the blade body in the testing process are guaranteed, and the testing efficiency is improved. The testing mechanism can adapt to rotor seats of different sizes and shapes and is more convenient to disassemble, the clamping plates are only required to be far away from the rotor seats, the whole structure is simple and convenient, and no extra tool is needed for processing.

Description

Technical Field

[0001] The utility model relates to the technical field of blade vibration frequency testing, in particular to a vibration frequency testing mechanism for moving blades based on a steam turbine. Background Art

[0002] With the rapid development of industrial technology, steam turbines, as important power conversion equipment, are increasingly used in the fields of electricity, chemical industry, etc. The performance of steam turbines is directly related to the operating efficiency and safety of the entire system. Among them, the vibration characteristics of moving blades, as one of the core components of steam turbines, have an important impact on the stability and safety of steam turbines.

[0003] Reference patent (CN201910487223.8) A device for measuring the natural frequency of a steam turbine moving blade belongs to the field of steam turbine design. The present invention is to solve the problem that the natural frequency of the moving blade cannot be accurately measured, resulting in the low pitch resonance of the actually processed moving blades, which causes the blades to break and cause turbine accidents, and the long-term safe operation of the steam turbine unit cannot be guaranteed. The device for measuring the natural frequency of a steam turbine moving blade includes a radio telemetry system, a data storage and display analysis system, a compressed air excitation system and a speed measurement system. The radio telemetry system is used to transmit radio waves, the data storage and display analysis system is used to record and analyze the natural frequency value of the blade, the compressed air excitation system is used to excite the blade, and the speed measurement system is used to measure the value of the rotor speed. The radio telemetry system is connected to the data storage and display analysis system. It is mainly used for measuring the natural frequency of steam turbine moving blades.

[0004] When testing the vibration frequency of impeller blades, the impeller is usually mounted and fixed on the rotating shaft, and then the vibration characteristics of the impeller under different exciting force frequencies brought by different rotational speeds are detected by changing the rotation rate of the rotating shaft. However, traditional steam turbine moving blade vibration frequency testing mechanisms mostly use a mechanical clamping method, and the blades are fixed by manually or mechanically adjusting the clamp. The clamping force is difficult to accurately control, which can easily cause the blades to shift or deform during the test. In addition, the fixture design is complex and cannot adapt to blades of different sizes and shapes. The disassembly process is cumbersome and requires additional tools for processing, which reduces the test efficiency. For this reason, the utility model provides a steam turbine moving blade vibration frequency testing mechanism. Utility Model Content

[0005] In view of the deficiencies in the prior art, the utility model provides a vibration frequency testing mechanism for moving blades of a steam turbine, which solves the problems of fixing the blades by manually or mechanically adjusting the clamps, the difficulty in accurately controlling the clamping force, which easily causes the blades to shift or deform during the test, and the complex design of the clamps, which cannot adapt to blades of different sizes and shapes, and the cumbersome disassembly process, which requires additional tools for processing and reduces the test efficiency.

[0006] To achieve the above purpose, the utility model is implemented by the following technical scheme: a turbine-based dynamic blade vibration frequency testing mechanism, including a test bracket, the test bracket, the test bracket is rotatably connected to a test shaft, the test shaft is provided with an active cavity, the active cavity is provided with a fixing mechanism for blade installation, and the fixing mechanism includes:

[0007] The limiting assembly comprises a cylinder fixedly connected to the inner wall of the movable cavity, the end of the cylinder is connected to a piston seat, the side wall of the piston seat is provided with an air pipe, the end of the air pipe is connected to a support plate, a sealing cavity is opened inside the support plate, a convex block is provided inside the sealing cavity, and the top of the convex block is connected to a clamping plate;

[0008] The clamping assembly includes piston rods arranged at four ends of a piston seat, a slide groove is arranged on the outer surface of the test shaft, a slide rod is fixedly connected to the inner wall of the slide groove, and a linkage assembly for driving a clamping plate is arranged at the end of the piston rod.

[0009] Preferably, the protrusion is fixedly connected to the clamping plate to form a T-shaped structure, and a rubber pad is fixedly connected to the front end surface of the clamping plate.

[0010] Preferably, the linkage assembly includes a support block fixedly connected to the top end of the piston rod, and both sides of the support block are provided with a first rotating shaft connected through a support plate, the outer surface of the first rotating shaft is connected to a connecting rod, and a second rotating shaft is provided at one end of the connecting rod away from the first rotating shaft.

[0011] Preferably, the outer surface of the test shaft is sleeved with a rotor seat, and the outer surface of the rotor seat is evenly distributed with blade bodies.

[0012] Preferably, two groups of electric push rods are fixedly connected to the inner wall of the test bracket, and push plates are fixedly connected to the telescopic ends of the electric push rods.

[0013] Preferably, the bottom of the support plate is in a U-shaped structure, and the support plate is slidably connected to the slide rod.

[0014] Beneficial Effects

[0015] The utility model provides a vibration frequency testing mechanism for moving blades of a steam turbine. Compared with the prior art, the utility model has the following beneficial effects:

[0016] Firstly, when the utility model is tested, the piston rod is extended and retracted through the work of the piston seat and the cylinder, and then the support block is pushed and retracted. The support plate forms a rotating structure with the support block through the second rotating shaft, the connecting rod and the first rotating shaft, so as to shrink the distance between the support plates on both sides and clamp the rotor seat. The force of clamping the rotor seat can be more accurate, thereby ensuring the stability and safety of the blade body during the test, so that the test mechanism can adapt to rotor seats of different sizes and shapes, and it is more convenient to disassemble by moving the clamping plate away from the rotor seat. The overall structure is simple and convenient, and no additional tools are required for processing.

[0017] Secondly, the utility model passes the blade body through the rotor seat on the outer surface of the test shaft, and then the cylinder works, injects gas into the sealing cavity inside the support plate through the piston seat and the air pipe, so that the clamping plate is pushed out of the sealing cavity through the protrusion, and the rotor seat on the outer surface of the test shaft is limited, which can prevent damage to the test equipment or personnel due to vibration or movement of the blade during the test. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the overall structure of the utility model;

[0019] Figure 2 This is a schematic diagram of the cross-sectional structure of the test shaft of the utility model;

[0020] Figure 3 This is a schematic diagram of the support plate driving structure of the utility model;

[0021] Figure 4 This is a schematic diagram of the internal structure of the support plate of the utility model.

[0022] In the figure: 1. test bracket; 2. test shaft; 201. movable chamber; 202. cylinder; 3. piston seat; 301. air pipe; 302. support plate; 303. sealing chamber; 304. bump; 305. splint; 4. rubber pad; 5. piston rod; 501. support block; 502. first rotating shaft; 503. connecting rod; 504. second rotating shaft; 6. slide groove; 601. slide rod; 7. rotor seat; 701. blade body; 8. electric push rod; 9. push plate. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0024] See also Figure 1-4 The utility model provides a technical solution: a vibration frequency testing mechanism for moving blades of a steam turbine, comprising a testing bracket 1, wherein the testing bracket 1 is rotatably connected to a testing shaft 2, wherein an active cavity 201 is provided inside the testing shaft 2, wherein a fixing mechanism for installing blades is provided inside the active cavity 201, wherein the fixing mechanism comprises:

[0025] The limiting assembly includes a cylinder 202 fixedly connected to the inner wall of the movable chamber 201, the end of the cylinder 202 is connected to the piston seat 3, the side wall of the piston seat 3 is provided with an air pipe 301, the end of the air pipe 301 is connected to a support plate 302, a sealing chamber 303 is opened inside the support plate 302, a convex block 304 is provided inside the sealing chamber 303, and a clamping plate 305 is connected to the top of the convex block 304;

[0026] The clamping assembly includes a piston seat 3 with piston rods 5 at four ends, a slide groove 6 on the outer surface of the test shaft 2, a slide rod 601 fixedly connected to the inner wall of the slide groove 6, and a linkage assembly for driving the clamping plate 305 at the end of the piston rod 5.

[0027] In this embodiment, the blade body 701 is inserted onto the outer surface of the test shaft 2 through the rotor seat 7, and then the cylinder 202 works, and gas is injected into the sealed cavity 303 inside the support plate 302 through the piston seat 3 and the air pipe 301, so that the clamping plate 305 is pushed out of the sealed cavity 303 through the protrusion 304, and the rotor seat 7 on the outer surface of the test shaft 2 is limited to prevent damage to the test equipment or personnel due to vibration or movement of the blade during the test. Then the support plate 302 slides on the slide rod 601 through the slide groove 6 to clamp the rotor seat 7.

[0028] In a preferred embodiment, the protrusion 304 and the clamp 305 are fixedly connected to form a T-shaped structure, and the front end face of the clamp 305 is fixedly connected with a rubber pad 4. The T-shaped structure prevents the protrusion 304 from falling off from the sealing cavity 303 during ejection. The contact between the rubber pad 4 and the blade is flexible, which can reduce the damage caused by the direct clamping of the blade by the clamp, and increase the friction during contact, thereby ensuring stability during clamping.

[0029] In a preferred embodiment, the linkage assembly includes a support block 501 fixedly connected to the top of the piston rod 5, and the two sides of the support block 501 are provided with a first rotating shaft 502 connected by a support plate, and the outer surface of the first rotating shaft 502 is connected with a connecting rod 503, and the end of the connecting rod 503 away from the first rotating shaft 502 is provided with a second rotating shaft 504. The piston rod 5 is extended and retracted through the work of the piston seat 3 and the cylinder 202, and then the support block 501 is pushed and retracted. The support plate 302 is connected to the support block 501 through the second rotating shaft 504, the connecting rod 503 and the first rotating shaft 502. A rotating structure is formed to shrink the distance between the support plates 302 on both sides, so as to clamp the rotor seat 7, and make the force for clamping the rotor seat 7 more accurate, thereby ensuring the stability and safety of the blade body 701 during the test, so that the test mechanism can adapt to rotor seats 7 of different sizes and shapes, and it is more convenient to disassemble by moving the clamping plate 305 away from the rotor seat 7. By adjusting the working pressure flow of the cylinder 202, the clamping force of the clamping plate 305 can be accurately controlled to adapt to blade bodies 701 of different specifications and shapes.

[0030] In a preferred embodiment, the outer surface of the test shaft 2 is sleeved with a rotor seat 7, and the outer surface of the rotor seat 7 is evenly distributed with blade bodies 701. The impeller is mounted and fixed on the test shaft 2, and then the vibration characteristics of the impeller at different exciting force frequencies brought by different rotational speeds are detected by changing the rotation rate of the rotating shaft to achieve the detection work. This belongs to the prior art and will not be elaborated in detail.

[0031] In a preferred embodiment, two sets of electric push rods 8 are fixedly connected to the inner wall of the test bracket 1, and the telescopic ends of the electric push rods 8 are fixedly connected to push plates 9. When disassembling, the electric push rods 8 can drive the push plates 9 to work, so that the rotor seat 7 slides forward along the test shaft 2, thereby performing disassembly, and the operation is simple and convenient.

[0032] Meanwhile, the contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0033] When working, the blade body 701 is passed through the rotor seat 7 on the outer surface of the test shaft 2, and then the cylinder 202 works, and the gas is injected into the sealed cavity 303 inside the support plate 302 through the piston seat 3 and the air pipe 301, so that the clamping plate 305 is pushed out of the sealed cavity 303 through the protrusion 304, and the rotor seat 7 on the outer surface of the test shaft 2 is limited;

[0034] The piston rod 5 is extended and retracted through the work of the piston seat 3 and the cylinder 202, and then the support block 501 is pushed and retracted. The support plate 302 forms a rotating structure with the support block 501 through the second rotating shaft 504, the connecting rod 503 and the first rotating shaft 502, so as to shrink the distance between the support plates 302 on both sides and clamp the rotor seat 7. The force for clamping the rotor seat 7 can be more accurate, thereby ensuring the stability and safety of the blade body 701 during the test, so that the test mechanism can adapt to rotor seats 7 of different sizes and shapes, and it is more convenient to disassemble, and the clamping plate 305 can be kept away from the rotor seat 7.

[0035] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0036] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A turbine-based moving blade vibration frequency testing mechanism, comprising a testing bracket (1), characterized in that: The test bracket (1) is rotatably connected to a test shaft (2) inside the test bracket (1), an active cavity (201) is provided inside the test shaft (2), and a fixing mechanism for blade installation is provided inside the active cavity (201), the fixing mechanism comprising: A limit assembly comprises a cylinder (202) fixedly connected to the inner wall of an active cavity (201), the end of the cylinder (202) being connected to a piston seat (3), the side wall of the piston seat (3) being provided with an air pipe (301), the end of the air pipe (301) being connected to a support plate (302), a sealing cavity (303) being provided inside the support plate (302), a convex block (304) being provided inside the sealing cavity (303), and a clamping plate (305) being connected to the top end of the convex block (304); The clamping assembly comprises a piston seat (3) with piston rods (5) arranged at four ends, the outer surface of the test shaft (2) is provided with a slide groove (6), the inner wall of the slide groove (6) is fixedly connected with a slide rod (601), and the end of the piston rod (5) is provided with a linkage assembly for driving a clamping plate (305).

2. The turbine-based moving blade vibration frequency testing mechanism according to claim 1, characterized in that: The protrusion (304) and the clamping plate (305) are fixedly connected to form a T-shaped structure, and the front end surface of the clamping plate (305) is fixedly connected to a rubber pad (4).

3. The turbine-based moving blade vibration frequency testing mechanism according to claim 1, characterized in that: The linkage assembly comprises a support block (501) fixedly connected to the top end of a piston rod (5); both sides of the support block (501) are provided with a first rotating shaft (502) connected via a support plate; the outer surface of the first rotating shaft (502) is connected with a connecting rod (503); and the end of the connecting rod (503) away from the first rotating shaft (502) is provided with a second rotating shaft (504).

4. The turbine-based moving blade vibration frequency testing mechanism according to claim 1, characterized in that: The outer surface of the test shaft (2) is sleeved with a rotor seat (7), and the outer surface of the rotor seat (7) is evenly distributed with blade bodies (701).

5. The turbine-based moving blade vibration frequency testing mechanism according to claim 1, characterized in that: Two groups of electric push rods (8) are fixedly connected to the inner wall of the test bracket (1), and push plates (9) are fixedly connected to the telescopic ends of the electric push rods (8).

6. The turbine-based moving blade vibration frequency testing mechanism according to claim 1, characterized in that: The bottom of the support plate (302) is in a U-shaped structure, and the support plate (302) is slidably connected to the sliding rod (601).

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