Gap adjusting device and method for rotating speed probe of steam turbine

Abstract

The invention relates to a gap adjustment device and method for a turbine rotating speed probe. The gap adjustment device comprises a fixing module, a gap detection module, an adjustment execution module and a control module. The fixing module comprises a fixing base and an adjusting support, and the fixing base is installed on the steam turbine body. The adjusting support is provided with a rotating speed probe and located above the rotating speed gear disc, and the two ends of the rotating speed probe are slidably connected with the fixing bases at the corresponding positions. The gap detection module comprises a gap sensor which is installed on the adjusting support and is parallel to the rotating speed probe, and the detection ends of the gap sensor directly face the rotating speed gear disc. The adjusting execution module is used for adjusting the position of the adjusting bracket; the control module is used for adjusting the position of the adjusting support through the adjusting execution module according to the actual gap value transmitted by the gap sensor. Compared with the prior art, the method has the advantages that dynamic closed-loop adjustment is achieved, manual static calibration limitation is broken through, the service life of the probe is prolonged, and the rotating speed measurement accuracy is improved.

Description

Technical Field

[0001] This invention relates to the field of turbine speed probe adjustment technology, and in particular to a turbine speed probe gap adjustment device and method. Background Technology

[0002] Currently, speed measurement of rotating equipment such as steam turbines in power plants generally relies on speed probes (such as eddy current probes and magnetoelectric speed probes). Their working principle involves sensing a signal through the gap between the probe and a speed gear disk (or measuring disk) fixed on the rotating shaft, converting this signal into speed data. In existing technologies, speed probes are typically rigidly mounted on the equipment body using a fixed bracket. For example, in the invention disclosed in CN111766396A, which describes a device and method for measuring the time constant of a speed probe and a preamplifier, the initial gap between the probe and the speed gear disk needs to be manually calibrated while the equipment is stopped (generally set to 0.5-2 mm, with the specific value determined according to the probe type).

[0003] However, during turbine operation, factors such as shaft thermal deformation, bearing wear, and load fluctuations can cause shaft eccentricity (i.e., the shaft center deviates from the theoretical rotation center). This eccentricity causes the gap between the speed gear and the probe to change periodically with shaft rotation: when the gap is too small, the probe and gear are prone to rubbing against each other, causing probe head wear and directly leading to probe failure; when the gap is too large, the probe's sensing signal weakens, the signal-to-noise ratio decreases, and problems such as speed data jumps, increased measurement errors, and even signal loss may occur.

[0004] The existing solutions to the above problems are merely "periodic shutdown for manual adjustment of the gap" or "replacing the probe after a failure," which have obvious shortcomings: 1. Manual adjustments rely on the experience of maintenance personnel and require downtime, affecting the continuous operating efficiency of the equipment; 2. It cannot dynamically respond to real-time changes in the gap during operation, making it difficult to avoid probe damage and measurement deviations caused by abnormal gaps; 3. Frequent probe replacements increase equipment maintenance costs, and sudden probe failures may cause speed monitoring to fail, posing a risk to the safe operation of the equipment. Summary of the Invention

[0005] The purpose of this invention is to overcome the defects of the prior art by providing a turbine speed probe gap adjustment device and method, realizing dynamic closed-loop adjustment of the speed probe gap and extending the probe's service life.

[0006] The objective of this invention can be achieved through the following technical solutions: A gap adjustment device for a steam turbine speed probe includes a fixing module, a gap detection module, an adjustment execution module, and a control module; The fixing module includes a fixing seat and an adjusting bracket. The fixing seat is installed on the turbine body and there are multiple fixing seats, which are located on both sides of the speed gear disk in the turbine body. The adjusting bracket is equipped with a speed probe, located above the speed gear disk, and its two ends are slidably connected to the fixing seat at the corresponding position. The gap detection module includes a gap sensor, which is mounted on an adjustment bracket, positioned parallel to the speed probe, with both detection ends facing the speed gear disk. The gap sensor is used to collect the actual gap value between the speed probe and the speed gear disk and transmit it to the control module. The adjustment execution module is installed at the sliding connection between the adjustment bracket and the fixed base, and is used to adjust the position of the adjustment bracket; The control module is used to adjust the position of the adjusting bracket by adjusting the execution module according to the actual gap value transmitted by the gap sensor, so as to achieve the optimal gap threshold.

[0007] Furthermore, the adjustment bracket is a U-shaped frame and is provided with a probe mounting slot for mounting the speed probe.

[0008] Furthermore, both ends of the adjustment bracket are connected to the fixed base via sliding guide rails, so as to move linearly in the direction of approaching or moving away from the rotating gear disk.

[0009] Furthermore, the fixing base has an L-shaped structure, including a bottom horizontal connecting part and a vertical connecting part that are connected to each other. The bottom horizontal connecting part is fixed on the turbine body, and the sliding guide rail is installed on the vertical connecting part.

[0010] Furthermore, the adjustment execution module includes a micro servo motor, a ball screw, a screw nut, and a limit assembly. The micro servo motor is fixed to the side wall of the fixed base. The motor output shaft of the micro servo motor is connected to the ball screw via a coupling. The screw nut is connected to the ball screw and is rigidly connected to the bottom of the adjustment bracket. The limiting component is mounted on the fixed base to limit the movement range of the adjusting bracket. Both the limiting component and the micro servo motor are communicatively connected to the control module.

[0011] Furthermore, the limiting component includes a first photoelectric limit switch and a second photoelectric limit switch, which are located at the minimum gap position and the maximum gap position of the moving path of the adjusting bracket, respectively. They are used to sense the adjusting bracket and transmit a trigger signal to the control module. The control module cuts off the power supply of the micro servo motor and issues a limit alarm signal based on the trigger signals of the first photoelectric limit switch and the second photoelectric limit switch.

[0012] Furthermore, the ball screw is arranged in a direction that is close to or far from the rotating gear disc.

[0013] Furthermore, the gap sensor is a miniature eddy current gap sensor.

[0014] Furthermore, the detection end of the gap sensor is positioned directly opposite the tooth tip of the rotating gear disk or the surface of the measuring disk.

[0015] The present invention also provides a method for adjusting the gap of a turbine speed probe gap adjustment device as described above, comprising the following steps: After the turbine body's speed gear disk and speed probe are started, the actual gap value between the speed probe and the speed gear disk is collected by the gap sensor and transmitted to the control module; The control module compares the actual gap value with the pre-stored optimal gap threshold. If the actual gap value is greater than the upper limit of the optimal gap threshold, the adjustment execution module is driven to push the adjustment bracket toward the direction of the rotating gear disk until the actual gap value returns to within the optimal gap threshold. If the actual gap value is less than the lower limit of the optimal gap threshold, the adjustment execution module is driven to push the adjustment bracket to move away from the rotating gear disk until the actual gap value returns to within the optimal gap threshold. If the actual gap value is within the optimal gap threshold, then the adjustment execution module remains stationary; The actual gap value is displayed in real time by the control module via a display screen.

[0016] Compared with the prior art, the present invention has the following improvements: (1) Dynamic closed-loop adjustment, breaking through the limitations of manual static calibration: Existing technologies rely on manual adjustment during shutdown. This invention achieves the installation of the gap sensor by setting up a fixed seat and adjustment bracket through the closed-loop control of "gap detection-signal processing-motor drive". The gap sensor is set parallel to the speed probe to collect the actual gap value between the speed probe and the speed gear disk. The actual gap value is compared with the optimal gap threshold by the control module. The adjustment execution module adjusts the position of the adjustment bracket to achieve real-time response to gap changes during turbine operation. The optimal gap can be maintained without stopping the machine, solving the problem of dynamic gap fluctuation caused by shaft eccentricity. (2) Integrated design with strong adaptability: The device integrates the fixing module, gap detection module, adjustment execution module and control module into one unit. It is compact in size and the fixing base adopts a universal bolt hole design, which can directly replace the existing speed probe fixing bracket without modifying the turbine body. It is compatible with mainstream brand speed probes and turbine models. (3) Multiple protection mechanisms, high safety: Two photoelectric limit switches are set at the minimum gap position and the maximum gap position to adjust the bracket position detection, prevent excessive adjustment and avoid probe rubbing; at the same time, the control module has a fault alarm function, which can detect problems such as sensor failure and motor failure in time, and reduce the risk of equipment damage. (4) Intelligent control and convenient operation and maintenance: The parameters can be visualized and manually intervened through the touch screen. No professional personnel are required to operate it, reducing the workload of operation and maintenance; the PLC can store historical gap data and fault records, which is convenient for later operation and maintenance analysis.

[0017] It also has the following beneficial effects: 1) Extend probe lifespan: By dynamically maintaining the optimal gap, the contact and friction between the probe and the speed gear disk are completely avoided, reducing the replacement frequency of the probe due to mechanical damage. It is estimated that the lifespan of the speed probe can be extended by 3-5 times. 2) Improve the accuracy of speed measurement: When the gap is kept within the optimal threshold range, the strength and stability of the probe sensing signal can be guaranteed, avoiding equipment shutdown or safety hazards caused by inaccurate measurement; 3) Reduced operation and maintenance costs and workload: No need for regular downtime for manual adjustment of gaps, reducing the number of on-site operations by maintenance personnel; reduced probe replacement frequency, saving probe procurement costs and replacement time; 4) Improve equipment reliability: The device itself has fault alarm and limit protection functions, which can provide timely warning of potential problems, avoid speed monitoring failure due to probe failure, ensure continuous and stable operation of the steam turbine, and reduce the probability of unplanned shutdowns; 5) High versatility and high promotion value: It is not only applicable to steam turbines, but also compatible with speed probes of other rotating equipment such as fans and water pumps. There is no need to redesign for different equipment, and the application scenarios are wide. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a turbine speed probe gap adjustment device provided in an embodiment of the present invention; In the diagram, 1. turbine body, 2. fixed base, 3. adjusting bracket, 4. speed probe, 5. gap sensor, 6. micro servo motor, 7. ball screw, 8. screw nut, 9. first photoelectric limit switch, 10. second photoelectric limit switch, 11. control module, 12. speed gear disk, 13. sliding guide rail. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0021] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0022] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed during use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0023] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0024] Furthermore, terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0025] Example 1 like Figure 1 As shown, this embodiment provides a gap adjustment device for a steam turbine speed probe, including a fixing module, a gap detection module, an adjustment execution module, and a control module 11; The fixing module includes a fixing seat 2 and an adjusting bracket 3. The fixing seat 2 is installed on the turbine body 1, and there are multiple fixing seats, which are located on both sides of the speed gear disk 12 in the turbine body 1. The adjusting bracket 3 is equipped with a speed probe 4, which is located above the speed gear disk 12, and its two ends are slidably connected to the fixing seat 2 at the corresponding positions. The gap detection module includes a gap sensor 5, which is mounted on the adjustment bracket 3, positioned parallel to the speed probe 4, with both detection ends facing the speed gear disk 12. The gap sensor 5 is used to collect the actual gap value between the speed probe 4 and the speed gear disk 12 and transmit it to the control module 11. The adjustment execution module is installed at the sliding connection between the adjustment bracket 3 and the fixed base 2, and is used to adjust the position of the adjustment bracket 3; The control module 11 is used to adjust the position of the adjusting bracket 3 according to the actual gap value transmitted by the gap sensor 5 through the adjustment execution module to achieve the optimal gap threshold.

[0026] Preferably, the adjusting bracket 3 is a U-shaped frame that matches the shape of the extended part of the speed gear disk 12; and it is provided with a probe mounting slot for mounting the speed probe 4, which is compatible with mainstream speed probes.

[0027] Optionally, the two ends of the adjusting bracket 3 are connected to the fixed base 2 via sliding guide rails 13, so as to move linearly in the direction of approaching or moving away from the rotating gear disk 12.

[0028] Preferably, the fixing seat 2 is an L-shaped metal structure, including a bottom horizontal connecting part and a vertical connecting part that are connected to each other. The bottom horizontal connecting part is fixed on the turbine body 1, and the sliding guide rail 13 is installed on the vertical connecting part.

[0029] In this embodiment, the fixed base 2 is an L-shaped metal structure, which is rigidly connected to the non-rotating part of the turbine body near the speed gear disk by bolts, serving as the installation base of the device; There are two fixed seats 2, located on both sides of the position of the medium-speed gear disk in the turbine body, and the vertical connecting parts of the two fixed seats 2 are close to each other.

[0030] Preferably, the gap sensor 5 is a miniature eddy current gap sensor with an accuracy of ±0.01mm. This sensor is mounted parallel to the speed probe on the adjustment bracket, and the detection end is facing the tooth tip of the speed gear disk or the surface of the measuring disk. It is used to collect the actual gap value between the probe and the gear disk in real time and convert the gap signal into a 4-20mA analog electrical signal and transmit it to the control module.

[0031] Preferably, the adjustment execution module includes a micro servo motor 6, a ball screw 7, a screw nut 8, and a limit assembly. The micro servo motor 6 is fixed to the side wall of the fixed base 2. The motor output shaft of the micro servo motor 6 is connected to the ball screw 7 through a coupling. The screw nut 8 is connected to the ball screw 7 and is rigidly connected to the bottom of the adjustment bracket 3. The limit component is installed on the fixed base 2 to limit the movement range of the adjustment bracket 3. Both the limit component and the micro servo motor 6 are communicatively connected to the control module 11.

[0032] The ball screw 7 is arranged in a direction that is close to or far from the speed gear disk 12.

[0033] The miniature servo motor has a rated power of 10-20W and a speed of 500-1000rpm.

[0034] Optionally, the limiting component includes a first photoelectric limit switch 9 and a second photoelectric limit switch 10, which are located at the minimum gap position and the maximum gap position of the moving path of the adjusting bracket 3, respectively. They are used to sense the adjusting bracket 3 and transmit the trigger signal to the control module 11. The control module 11 cuts off the power supply of the micro servo motor 6 and issues a limit alarm signal according to the trigger signals of the first photoelectric limit switch 9 and the second photoelectric limit switch 10, so as to prevent the probe from rubbing or the gap from exceeding the limit due to excessive adjustment.

[0035] Optionally, the control module 11 is based on a PLC controller or a microcontroller, and is equipped with a touch screen and a signal conditioning unit. The signal conditioning unit receives the analog signal from the gap sensor, filters and amplifies it before transmitting it to the PLC. The PLC has a pre-stored "optimal gap threshold" (set according to the type of speed probe, such as 1.0±0.2mm for an eddy current probe). By comparing the "actual gap value" with the "optimal threshold", it outputs a PWM control signal to the servo motor driver to drive the motor to rotate forward or backward. The touch screen is used to display the real-time gap value, motor status, and fault alarm information, and supports manual modification of the optimal gap threshold.

[0036] Example 2 This embodiment provides a method for adjusting the gap of the turbine speed probe gap adjustment device as described above, including the following steps: S1: After the turbine body 1 starts up, the actual gap value between the speed probe 4 and the speed gear 12 is collected by the gap sensor 5 and transmitted to the control module 11. S2: By comparing the actual gap value with the pre-stored optimal gap threshold through the control module 11, if the actual gap value is greater than the upper limit of the optimal gap threshold, the adjustment execution module is driven to push the adjustment bracket 3 to move closer to the rotational gear disk 12 until the actual gap value returns to within the optimal gap threshold. If the actual clearance value is less than the lower limit of the optimal clearance threshold, the drive adjustment execution module pushes the adjustment bracket 3 to move away from the rotational gear disk 12 until the actual clearance value returns to within the optimal clearance threshold. If the actual gap value is within the optimal gap threshold, then keep the adjustment execution module stationary; S3: Limit protection is achieved by adjusting the execution module; S4: The actual gap value is displayed in real time by the control module 11 through the display screen.

[0037] In this embodiment, step S2 specifically includes: 1. If the actual gap is greater than the upper limit of the optimal threshold (e.g., greater than 1.2mm), the PLC output signal drives the servo motor to rotate forward, which in turn drives the ball screw to rotate. The screw nut pushes the adjusting bracket to move closer to the gear plate until the gap returns to the optimal threshold range. 2. If the actual gap is less than the lower limit of the optimal threshold (e.g., less than 0.8mm), the PLC output signal drives the servo motor to reverse, and the adjusting bracket moves away from the gear plate until the gap returns to the optimal threshold range; 3. If the actual gap is within the optimal threshold range, the servo motor remains stationary; Step S3 specifically includes: When the adjustment bracket moves to the "maximum gap end" or "minimum gap end", the corresponding photoelectric limit switch is triggered. The PLC immediately cuts off the power to the servo motor to prevent over-adjustment and sends a "limit alarm" signal through the touch screen. Step S4 specifically includes: During operation, the touch screen updates the gap data and equipment status in real time. If the gap sensor fails or the motor is overloaded, the PLC will trigger the corresponding fault alarm to prompt the maintenance personnel to handle it.

[0038] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A gap adjustment device for a steam turbine speed probe, characterized in that, It includes a fixing module, a gap detection module, an adjustment execution module and a control module (11); The fixing module includes a fixing seat (2) and an adjusting bracket (3). The fixing seat (2) is installed on the turbine body (1) and there are multiple fixing seats, which are located on both sides of the speed gear disk (12) in the turbine body (1). The adjusting bracket (3) is equipped with a speed probe (4), which is located above the speed gear disk (12) and its two ends are slidably connected to the fixing seat (2) at the corresponding positions. The gap detection module includes a gap sensor (5), which is mounted on the adjustment bracket (3) and positioned parallel to the speed probe (4), with the detection ends facing the speed gear disk (12). The gap sensor (5) is used to collect the actual gap value between the speed probe (4) and the speed gear disk (12) and transmit it to the control module (11). The adjustment execution module is installed at the sliding connection between the adjustment bracket (3) and the fixed base (2) and is used to adjust the position of the adjustment bracket (3); The control module (11) is used to adjust the position of the adjusting bracket (3) by adjusting the execution module according to the actual gap value transmitted by the gap sensor (5) in order to achieve the optimal gap threshold.

2. The gap adjustment device for a steam turbine speed probe according to claim 1, characterized in that, The adjustment bracket (3) is a U-shaped frame and is provided with a probe mounting slot for mounting the speed probe (4).

3. The gap adjustment device for a steam turbine speed probe according to claim 1, characterized in that, The two ends of the adjustment bracket (3) are connected to the fixed base (2) via sliding guide rails (13) to move linearly along the direction of approaching or moving away from the rotating gear disk (12).

4. The gap adjustment device for a steam turbine speed probe according to claim 3, characterized in that, The fixed seat (2) has an L-shaped structure, including a bottom horizontal connecting part and a vertical connecting part that are connected to each other. The bottom horizontal connecting part is fixed on the turbine body (1), and the sliding guide rail (13) is installed on the vertical connecting part.

5. The gap adjustment device for a steam turbine speed probe according to claim 3, characterized in that, The adjustment execution module includes a micro servo motor (6), a ball screw (7), a screw nut (8), and a limit assembly. The micro servo motor (6) is fixed to the side wall of the fixed base (2). The motor output shaft of the micro servo motor (6) is connected to the ball screw (7) through a coupling. The screw nut (8) is connected to the ball screw (7). The screw nut (8) is rigidly connected to the bottom of the adjustment bracket (3). The limiting component is mounted on the fixed base (2) to limit the movement range of the adjusting bracket (3). The limiting component and the micro servo motor (6) are both communicatively connected to the control module (11).

6. The gap adjustment device for a steam turbine speed probe according to claim 5, characterized in that, The limiting component includes a first photoelectric limit switch (9) and a second photoelectric limit switch (10), which are located at the minimum gap position and the maximum gap position of the moving path of the adjusting bracket (3), respectively. They are used to sense the adjusting bracket (3) and transmit the trigger signal to the control module (11). The control module (11) cuts off the power supply of the micro servo motor (6) and issues a limit alarm signal according to the trigger signals of the first photoelectric limit switch (9) and the second photoelectric limit switch (10).

7. The gap adjustment device for a steam turbine speed probe according to claim 5, characterized in that, The ball screw (7) is arranged in a direction close to or away from the rotating gear disk (12).

8. The gap adjustment device for a steam turbine speed probe according to claim 1, characterized in that, The gap sensor (5) is a miniature eddy current gap sensor.

9. The gap adjustment device for a steam turbine speed probe according to claim 1, characterized in that, The detection end of the gap sensor (5) is facing the tooth tip of the rotating gear disk (12) or the surface of the measuring disk.

10. A method for adjusting the gap of a turbine speed probe gap adjustment device as described in any one of claims 1-9, characterized in that, Includes the following steps: After the turbine body (1)’s speed gear disk (12) and speed probe (4) are started, the actual gap value between the speed probe (4) and the speed gear disk (12) is collected by the gap sensor (5) and transmitted to the control module (11). By comparing the actual gap value with the pre-stored optimal gap threshold by the control module (11), if the actual gap value is greater than the upper limit of the optimal gap threshold, the adjustment execution module is driven to push the adjustment bracket (3) to move closer to the rotational gear disk (12) until the actual gap value returns to within the optimal gap threshold. If the actual gap value is less than the lower limit of the optimal gap threshold, the adjustment execution module is driven to push the adjustment bracket (3) to move away from the rotational gear disk (12) until the actual gap value returns to within the optimal gap threshold. If the actual gap value is within the optimal gap threshold, then the adjustment execution module remains stationary; The actual gap value is displayed in real time by the control module (11) through the display screen.

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