A method for adjusting the pressing stroke of a water turbine guide vane servomotor

Abstract

This invention belongs to the technical field of hydropower equipment, and specifically relates to a method for adjusting the clamping stroke of a turbine guide vane servo. The invention includes the following steps: placing the guide vane servo and control ring in the fully closed position; applying stepwise pressurization to the closed chamber of the guide vane servo, recording the chamber pressure and piston rod displacement values ​​after each pressurization until the piston rod displacement change rate significantly decreases and pressurization is stopped; plotting a pressure-displacement relationship curve based on the recorded chamber pressure and piston rod displacement values, identifying the inflection point on the curve, and determining the oil pressure value corresponding to the inflection point as the optimal clamping stroke adjustment oil pressure value; adjusting the piston position of the hydraulic locking servo and / or mechanical locking servo according to the optimal clamping stroke adjustment oil pressure value, so that the guide vane servo achieves the target clamping stroke. This invention provides a scientific, accurate, and repeatable method for adjusting the clamping stroke of a turbine guide vane servo, achieving precise control of the clamping stroke.

Description

Technical Field

[0001] This invention belongs to the technical field of hydropower equipment, and specifically relates to a method for adjusting the clamping stroke of a turbine guide vane servo. Background Technology

[0002] The clamping stroke of the turbine guide vane servo is designed to generate a certain clamping force on the movable guide vane and its operating mechanism during the closing process. This clamping force causes elastic deformation of the movable guide vane and its operating structure, reducing or compensating for the guide vane clearance caused by hydraulic torque, installation errors, or manufacturing inaccuracies, thereby reducing guide vane leakage. Excessive clamping stroke may damage the guide vane mechanism components, while insufficient clamping stroke will increase leakage, cause turbine creep, or even prevent shutdown. The principle for adjusting the clamping stroke is to maximize the elastic deformation range of the movable guide vane and its operating structure within the guide vane servo's pre-set stroke range. Currently, the method for adjusting the clamping stroke of the guide vane servo is to measure the rebound value of the guide vane servo piston rod after the oil pressure is removed, or the displacement value of the piston rod when the oil pressure is gradually increased from zero to the specific oil pressure, using a dial indicator under a specific oil pressure. The principle for determining a specific hydraulic pressure is that, under low hydraulic pressure conditions during a governor accident, the guide vane servo can move to the fully closed position (i.e., the gap between the guide vane servo piston and the open end cover is 0), and the servo hydraulic locking pin can be reliably engaged, while the pressure reserved between the movable guide vanes is sufficiently large. Currently, specific hydraulic pressures are typically determined using the following methods: low hydraulic pressure during an accident, rated hydraulic pressure, and 50% of rated hydraulic pressure. The guide vane servo clamping stroke is a key parameter for ensuring the tightness of the guide vane closure. Traditional adjustment methods have the following shortcomings: 1. The compression stroke relies heavily on experience for adjustment and lacks scientific quantitative basis.

[0003] 2. The dynamic relationship between oil pressure and displacement was not considered during the adjustment process.

[0004] 3. The adjustment value of the clamping stroke is difficult to determine accurately, which can easily lead to large water leakage or damage to the mechanism.

[0005] 4. No systematic method for measuring oil pressure has been established. Summary of the Invention

[0006] In order to solve the above-mentioned problems in the existing technology, the purpose of this invention is to provide a scientific, accurate and repeatable method for adjusting the clamping stroke of a turbine guide vane servo, so as to achieve precise control of the clamping stroke.

[0007] The technical solution adopted in this invention is as follows: A method for adjusting the clamping stroke of a turbine guide vane servo connector includes the following steps: System preparation steps: Place the guide vane servo and control ring in the fully closed position, install a pressure transmitter in the closed chamber of the guide vane servo, and install a displacement sensor at the end of the piston rod of the guide vane servo. Dynamic pressurization test procedure: Apply stepwise pressurization to the closing chamber of the guide vane servo, record the closing chamber pressure value and piston rod displacement value after each pressurization, and stop pressurization when the piston rod displacement change rate decreases significantly; Characteristic curve analysis steps: Plot the pressure-displacement relationship curve based on the recorded chamber pressure value and piston rod displacement value, identify the inflection point on the curve, and determine the oil pressure value corresponding to the inflection point as the optimal clamping stroke adjustment oil pressure value; Clamping stroke adjustment steps: Adjust the oil pressure value according to the optimal clamping stroke, and adjust the piston position of the hydraulic locking spindle servo and / or mechanical locking spindle servo so that the guide vane servo obtains the target clamping stroke.

[0008] This invention utilizes a high-precision pressure transmitter and displacement sensor to apply stepwise pressure to the closing chamber of the guide vane servo, simultaneously recording the chamber pressure and piston rod displacement. A pressure-displacement curve is plotted, and the inflection point is identified. The oil pressure value corresponding to this inflection point is used as the basis for adjusting the clamping stroke. This method is scientific and accurate, effectively avoiding the shortcomings of traditional experience-based adjustments and improving unit operating efficiency and safety. This invention provides a scientific, accurate, and repeatable method for adjusting the clamping stroke of a turbine guide vane servo, achieving precise control of the clamping stroke.

[0009] As a preferred embodiment of the present invention, in the dynamic pressurization test step, the pressure increase gradient for pressurizing the guide vane relay closing chamber is 0.2 MPa / cycle.

[0010] As a preferred embodiment of the present invention, in the characteristic curve analysis step, the identification criterion for the inflection point is: the rate of change of piston rod displacement decreases to less than 50% of the rate of change of displacement at the previous sampling point.

[0011] As a preferred embodiment of the present invention, in the dynamic pressurization test step, the condition for stopping pressurization is: the piston rod displacement change rate decreases to less than 50% of the displacement change rate of the previous sampling point, and the guide vane limiting gap of the guide vane relay in the fully closed position meets the design requirements.

[0012] As a preferred embodiment of the present invention, in the system preparation step, the installed pressure transmitter has an accuracy class of not less than 0.5, and the installed displacement sensor is a wire-type displacement sensor with a resolution of not less than 0.01 mm.

[0013] As a preferred embodiment of the present invention, the dynamic pressurization test step further includes a pre-pressurization step before the stepped pressurization: pressurizing the guide vane relay cavity to 1MPa and then slowly depressurizing it to 0, and checking the guide vane vertical clearance.

[0014] As a preferred embodiment of the present invention, the pressing stroke adjustment step further includes: if the difference between the pressing stroke calculated by the hydraulic locking spindle relay and the mechanical locking spindle relay is greater than 1mm, it is determined that there is asynchronous tension and corresponding adjustments are made.

[0015] As a preferred embodiment of the present invention, the method of adjusting the piston position in the pressing stroke adjustment step includes rotating the eccentric pin, machining an adjusting washer, or rotating the guide vane relay rod head.

[0016] As a preferred embodiment of the present invention, the target clamping stroke is determined according to the following principle: if the designed reserved clamping stroke value A is greater than the actual clamping stroke value S calculated by the pressure-displacement curve, the adjustment is made according to the value of S; if the difference between S and A is within the allowable range, the adjustment is made according to the value of A.

[0017] As a preferred embodiment of the present invention, in the system preparation step, when the hydraulic lock spindle relay and the mechanical lock spindle relay are designed to reserve a clamping stroke value A in the direction of the guide vane opening, the deviation is controlled to be less than 0.5mm.

[0018] The beneficial effects of this invention are as follows: This invention utilizes a high-precision pressure transmitter and displacement sensor to apply stepwise pressure to the closing chamber of the guide vane servo, simultaneously recording the chamber pressure and piston rod displacement. A pressure-displacement curve is plotted, and the inflection point is identified. The oil pressure value corresponding to this inflection point is used as the basis for adjusting the clamping stroke. This method is scientific and accurate, effectively avoiding the shortcomings of traditional experience-based adjustments and improving unit operating efficiency and safety. This invention provides a scientific, accurate, and repeatable method for adjusting the clamping stroke of a turbine guide vane servo, achieving precise control of the clamping stroke. Attached Figure Description

[0019] Figure 1 This is a structural schematic diagram of the guide vane relay system; Figure 2 yes Figure 1 A magnified view of a section at point A in the middle; Figure 3 yes Figure 1 A magnified view of a section at point B in the middle; Figure 4 This is an installation structure diagram of a pressure transmitter; Figure 5 This is a diagram of the piston rod displacement transmitter installation structure; Figure 6 It is a graph showing the relationship between pressure and displacement.

[0020] In the diagram: 1-Pressure transmitter; 2-Displacement sensor; 3-Mechanical locking relay; 4-Hydraulic locking relay; 5-Moving guide vane; 6-Control loop. Detailed Implementation

[0021] 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.

[0022] 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. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the invention can be combined with each other.

[0023] The method for adjusting the clamping stroke of the turbine guide vane servo in this embodiment includes the following steps: S1: System Preparation (see...) Figures 1-3 ): S11: Place the guide vane relay and control ring 6 in the fully closed position.

[0024] S12: Move the hydraulic locking spindle relay 4 and the mechanical locking spindle relay 3 to the guide vane opening direction by a preset distance A (A is the design reserved clamping stroke value), and the deviation should be less than 0.5mm.

[0025] S13: Check that the clearance between the five vertical surfaces of the movable guide vane meets the requirements.

[0026] S14: A high-precision pressure transmitter (accuracy class not lower than 0.5) is installed in the closed chamber of the guide vane relay (see...). Figure 4 ).

[0027] S15: A wire-type displacement sensor 2 (resolution not less than 0.01mm) is installed at the end of the piston rod (see...). Figure 5 ).

[0028] S2: Dynamic Pressure Testing and Analysis S21: After pressurizing the guide vane relay chamber by 1 MPa, slowly depressurize it to 0 and check that the clearance between the guide vane surfaces meets the requirements.

[0029] S22: Move the guide vane servo displacement sensor 2 to 0, and use 2MPa to move the guide vane to full opening. Record the guide vane servo piston rod position value S1 at this time.

[0030] S23: Check that the guide vane limit clearance meets the requirements.

[0031] S24: Determination of the allowable stroke deviation of the relay. The value of (A+S1) should be equal to the design stroke of the relay, and the calculated deviation between the hydraulic locking relay 4 and the mechanical locking relay 3 should be less than 1mm. If the above conditions are not met, corresponding adjustments should be made before proceeding to steps S21 to S23.

[0032] S25: Use 2 MPa operating hydraulic pressure to move the guide vane servo to full closure, and check that the guide vane limit position in the fully closed position meets the design requirements.

[0033] S26: Close the guide vane servo motor cavity and depressurize to 0. Check that the clearance between the guide vane vertical surfaces meets the requirements. Set the guide vane servo motor displacement sensor 2 to 0.

[0034] S27: Slowly pressurize the guide vane servo motor closing chamber. Record the pressure value and piston rod displacement value simultaneously for every 0.2 MPa increase in pressure.

[0035] S28: In the wedge-shaped structure of the guide vane vertical clearance (guide vane closed and without pressure), record the oil pressure value when the guide vane vertical clearance is 0.

[0036] S29: Continue pressurizing until the rate of change of piston rod displacement of the servo motor significantly decreases, then stop pressurizing and record the oil pressure value N and piston rod displacement value B at this time. Check that the guide vane limit in the fully closed position meets the design requirements.

[0037] S210: Depressurize the pressure in the servo motor's closing chamber to 0 and record the displacement value C of the servo motor's piston rod.

[0038] S211: The clamping stroke of the relay is S=BC.

[0039] S212: Determination of asynchronous operation of relays. If the difference in the clamping stroke S between the hydraulic locking relay 4 and the mechanical locking relay 3 is greater than 1mm, there may be asynchronous force between the hydraulic locking relay 4 and the mechanical locking relay 3. Adjustments should be made accordingly before proceeding to steps S27 to S211.

[0040] S3: Characteristic Curve Plotting and Analysis (see...) Figure 6 ): S31: Plot the pressure-displacement relationship curve.

[0041] S32: Identify the inflection point of the curve: When the pressure rises to a certain value, the rate of change of piston rod displacement decreases significantly, that is, the rate of change of displacement decreases to less than 50% of the previous point.

[0042] S33: The oil pressure value corresponding to this inflection point is the optimal pressing stroke adjustment oil pressure value N.

[0043] S4: Compression stroke adjustment: S41: Based on the measured oil pressure value N and the structural characteristics of the guide vane servo, adjust the piston positions of the hydraulic locking pin and mechanical locking pin servo 3 by rotating the eccentric pin, machining the adjusting washer, and rotating the guide vane servo rod head, i.e., the gap between the servo piston and the opening end cover. If A>S, adjust the piston positions of the hydraulic locking pin servo 4 and mechanical locking pin servo 3 according to the value of S, and the difference in the pressing stroke of the two servos should not exceed 0.5mm; if S≈A, adjust the piston positions of the hydraulic locking pin servo 4 and mechanical locking pin servo 3 according to the value of A, and the difference in the pressing stroke of the two servos should not exceed 0.5mm.

[0044] S42: Repeat step S2 to check the clamping stroke of the relay.

[0045] S43: Measure the clearance between the guide vanes to ensure that the design requirements are met.

[0046] This invention improves adjustment accuracy: by determining the inflection point through a dynamic pressure-displacement curve, it avoids the arbitrariness of experience-based adjustments. This invention ensures operational safety: by scientifically determining the clamping stroke, it avoids damage to the guide vane mechanism due to excessive pressure or leakage due to insufficient pressure. This invention optimizes unit performance: by reducing guide vane leakage and improving turbine efficiency. This invention is simple and reliable to operate: using standard measuring instruments, the method is highly repeatable. This invention allows for preventative maintenance: by periodically monitoring changes in the clamping stroke, it can promptly detect wear or deformation of the guide vane mechanism.

[0047] This invention is not limited to the above-described optional embodiments. Anyone can derive other various forms of products under the guidance of this invention. However, regardless of any changes made in their shape or structure, any technical solution that falls within the scope of the claims of this invention shall be protected by this invention.

Claims

1. A method for adjusting the clamping stroke of a turbine guide vane servo connector, characterized in that, Includes the following steps: System preparation steps: Place the guide vane servo and control ring (6) in the fully closed position, install the pressure transmitter (1) in the closed chamber of the guide vane servo, and install the displacement sensor (2) at the end of the piston rod of the guide vane servo. Dynamic pressurization test procedure: Apply stepwise pressurization to the closing chamber of the guide vane servo, record the closing chamber pressure value and piston rod displacement value after each pressurization, and stop pressurization when the piston rod displacement change rate decreases significantly; Characteristic curve analysis steps: Plot the pressure-displacement relationship curve based on the recorded chamber pressure value and piston rod displacement value, identify the inflection point on the curve, and determine the oil pressure value corresponding to the inflection point as the optimal clamping stroke adjustment oil pressure value; Clamping stroke adjustment steps: Adjust the oil pressure value according to the optimal clamping stroke, adjust the piston position of the hydraulic locking pin servo (4) and / or the mechanical locking pin servo (3) so that the guide vane servo can obtain the target clamping stroke.

2. The method for adjusting the clamping stroke of the turbine guide vane servo as described in claim 1, characterized in that: In the dynamic pressurization test step, the pressure increase gradient for pressurizing the guide vane relay closing chamber is 0.2 MPa / cycle.

3. The method for adjusting the clamping stroke of the turbine guide vane servo as described in claim 1, characterized in that: In the characteristic curve analysis step, the inflection point identification criterion is: the piston rod displacement change rate decreases to less than 50% of the displacement change rate of the previous acquisition point.

4. The method for adjusting the clamping stroke of the turbine guide vane servo as described in claim 1, characterized in that: In the dynamic pressurization test step, the condition for stopping pressurization is: the piston rod displacement change rate decreases to less than 50% of the displacement change rate of the previous sampling point, and the guide vane limit gap in the fully closed position of the guide vane relay meets the design requirements.

5. The method for adjusting the clamping stroke of the turbine guide vane servo as described in claim 1, characterized in that: In the system preparation steps, the installed pressure transmitter (1) has an accuracy class of not less than 0.5, and the installed displacement sensor (2) is a wire-type displacement sensor (2) with a resolution of not less than 0.01mm.

6. The method for adjusting the clamping stroke of the turbine guide vane servo as described in claim 1, characterized in that: The dynamic pressurization test procedure includes a pre-pressurization step before the stepped pressurization: pressurizing the guide vane relay cavity to 1MPa and then slowly depressurizing it to 0, and checking the guide vane vertical clearance.

7. The method for adjusting the clamping stroke of the turbine guide vane servo as described in claim 1, characterized in that: The pressing stroke adjustment step further includes: if the difference between the pressing stroke calculated by the hydraulic locking pin relay (4) and the mechanical locking pin relay (3) is greater than 1mm, it is determined that there is asynchronous tension and corresponding adjustments are made.

8. The method for adjusting the clamping stroke of the turbine guide vane servo as described in claim 1, characterized in that: In the pressing stroke adjustment step, the piston position can be adjusted by rotating the eccentric pin, machining an adjusting washer, or rotating the guide vane relay rod head.

9. The method for adjusting the clamping stroke of the turbine guide vane servo as described in claim 1, characterized in that: The target clamping stroke is determined according to the following principles: if the designed reserved clamping stroke value A is greater than the actual clamping stroke value S calculated by the pressure-displacement curve, the adjustment is made according to the value of S; if the difference between S and A is within the allowable range, the adjustment is made according to the value of A.

10. The method for adjusting the clamping stroke of the turbine guide vane servo as described in claim 1, characterized in that: In the system preparation steps, when the hydraulic lock spindle relay (4) and the mechanical lock spindle relay (3) are designed to open in the direction of the guide vane, the reserved clamping stroke value A is controlled to be less than 0.5mm.

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