Auxiliary device for installing LVDT pull rod of turbine governing valve

Abstract

The utility model provides a steam turbine governing valve LVDT pull rod installation auxiliary device, when installing LVDT feedback device, the pull rod does not coincide with the coil center, will make the pull rod produce side stress in up and down movement, easily causes the pull rod fracture, seriously threatens the safe and stable operation of steam turbine unit, the utility model discloses a governing valve body and two LVDT sensors, the governing valve body is fixed with horizontal feedback rod through valve rod, the coil sleeve of two LVDT sensors is fixed on the governing valve body through connecting plate, the pull rod of two LVDT sensors is fixed on horizontal feedback rod, and the LVDT sensor is fixed with a centering centering frame for centering on every LVDT sensor, the utility model discloses a steam turbine governing valve LVDT pull rod installation auxiliary.

Description

Technical Field

[0001] This utility model relates to an auxiliary device for installing the LVDT tie rod of a steam turbine control valve. Background Technology

[0002] A linear variable differential transformer (LVDT) is a high-precision displacement sensor widely used in the position feedback of turbine inlet control valves. It accurately reflects the real-time opening of the turbine control valve and sends the feedback signal to the DEH system to participate in the regulation of the turbine's automatic control system. An LVDT consists of a coil and a pull rod, among other components. The valve drives the pull rod to move linearly within the coil. During installation, the coil sleeve is fixed to the control valve body, and the pull rod is fixed to the feedback rod on the valve stem. Normally, two redundant LVDT pull rods are fixed to the same horizontal feedback rod. If, during installation, the pull rod and coil center do not coincide, the two redundant pull rods will not be parallel, creating a "bell-mouth" effect. A single pull rod will tilt within the coil, rubbing against the inner wall. If this is compounded by factors such as high-frequency vibration of the control valve and valve stem rotation, lateral stress will be generated in the pull rod during its up-and-down movement, easily causing it to break and seriously threatening the safe and stable operation of the turbine unit. Summary of the Invention

[0003] To address the aforementioned problems, this utility model provides an auxiliary device for installing the LVDT tie rod of a steam turbine control valve.

[0004] The above objectives are achieved through the following scheme:

[0005] An auxiliary device for installing LVDT (Low Voltage Detector) levers in a steam turbine control valve comprises: a control valve body 12 and two LVDT sensors. The control valve body is fixed to a horizontal feedback rod 7 via a valve stem 11. The coil sleeves 9 of the two LVDT sensors are fixed to the control valve body via a connecting plate 8. The levers 10 of the two LVDT sensors are fixed to the horizontal feedback rod. Each LVDT sensor is fixed with a centering bracket for centering.

[0006] The centering frame includes an auxiliary support 4 and a centering block 5. The centering block is fixed to the lower end of the auxiliary support, and the upper end of the auxiliary support is fitted onto the coil sleeve of the LVDT sensor and fixed by bolts 6. The pull rod of the LVDT sensor passes through the centering block.

[0007] The auxiliary support includes a back plate 1, with an Ω-shaped collar 2 fixed at the upper end and a U-shaped collar 3 fixed at the lower end. The Ω-shaped collar and the U-shaped collar are arranged concentrically, and the centering block is fixed inside the U-shaped collar.

[0008] The centering block is cylindrical with a central notch. The outer diameter of the centering block is equal to that of the coil sleeve. The width of the central notch is equal to the diameter of the pull rod of the LVDT sensor. The pull rod of the LVDT sensor is inserted into the centering block in the radial direction. Beneficial effects

[0009] 1. This utility model device can ensure that the coil sleeve and the center of the pull rod coincide during the installation of the LVDT device, and no lateral stress caused by friction is generated during the up and down movement, thereby extending the service life of the pull rod and the coil and reducing the maintenance cost of the equipment.

[0010] 2. Using this utility model device can reduce the time spent finding the center position of the coil sleeve and the pull rod, thereby improving the installation efficiency of the LVDT device.

[0011] 3. This utility model device can ensure the accuracy of turbine control valve position feedback and improve the safety and reliability of unit operation. Attached Figure Description

[0012] Figure 1 This is the front view of the present invention;

[0013] Figure 2 This is a rendering of the present invention installed on the steam inlet regulating valve;

[0014] Figure 3 This is a schematic diagram of the structure of this utility model;

[0015] In the diagram: 1. Back plate; 2. Ω-shaped collar; 3. U-shaped collar; 4. Auxiliary bracket; 5. Centering block; 6. Bolt; 7. Horizontal feedback rod; 8. Connecting plate; 9. Coil sleeve; 10. Pull rod; 11. Valve stem; 12. Control valve body. Detailed Implementation

[0016] Reference Figures 1-3 An auxiliary device for installing LVDT (Low Voltage Detector) levers of a steam turbine control valve is provided. The device comprises a control valve body 12 and two LVDT sensors. The control valve body is fixed to a horizontal feedback rod 7 via a valve stem 11. The coil sleeves 9 of the two LVDT sensors are fixed to the control valve body via a connecting plate 8. The levers 10 of the two LVDT sensors are fixed to the horizontal feedback rod. Each LVDT sensor is fixed with a centering bracket for centering.

[0017] The centering frame includes an auxiliary support 4 and a centering block 5. The centering block is fixed to the lower end of the auxiliary support, and the upper end of the auxiliary support is fitted onto the coil sleeve of the LVDT sensor and fixed by bolts 6. The pull rod of the LVDT sensor passes through the centering block.

[0018] The auxiliary support includes a back plate 1, with an Ω-shaped collar 2 fixed at the upper end and a U-shaped collar 3 fixed at the lower end. The Ω-shaped collar and the U-shaped collar are arranged concentrically, and the centering block is fixed inside the U-shaped collar.

[0019] The centering block is cylindrical with a central notch. The outer diameter of the centering block is equal to that of the coil sleeve. The width of the central notch is equal to the diameter of the pull rod of the LVDT sensor. The pull rod of the LVDT sensor is inserted into the centering block in the radial direction.

[0020] Working principle: When installing the LVDT feedback device, first fix the coil sleeve on the regulating valve, and then install the LVDT sensor pull rod. Before installation, put the Ω-shaped collar on the auxiliary bracket on the lower part of the coil sleeve and tighten the bolts. The lower centering block will automatically align with the center of the coil sleeve. Then, insert the LVDT sensor pull rod into the center hole of the coil sleeve and adjust the position of the pull rod so that it is close to the center of the centering block. At this time, the position of the pull rod coincides with the center of the coil sleeve. Adjust the height of the pull rod. Finally, fix the pull rod on the horizontal feedback rod to complete the installation and remove the auxiliary device.

Claims

1. A turbine governing LVDT pull rod installation aid, comprising: The control valve body and two LVDT sensors are provided. The control valve body is fixed to the horizontal feedback rod via a valve stem. The control valve body is characterized in that the coil sleeves of the two LVDT sensors are fixed to the control valve body via a connecting plate, the pull rods of the two LVDT sensors are fixed to the horizontal feedback rod, and each LVDT sensor is fixed with a centering bracket for centering.

2. The turbine governing LVDT pull rod installation aid of claim 1, wherein: The centering frame includes an auxiliary support and a centering block. The centering block is fixed to the lower end of the auxiliary support, and the upper end of the auxiliary support is fitted onto the coil sleeve of the LVDT sensor and fixed with bolts. The pull rod of the LVDT sensor passes through the centering block.

3. The turbine governing LVDT pull rod installation aid of claim 2, wherein: The auxiliary support includes a back plate, an Ω-shaped collar is fixed at the upper end of the back plate, and a U-shaped collar is fixed at the lower end. The Ω-shaped collar and the U-shaped collar are arranged concentrically, and the centering block is fixed inside the U-shaped collar.

4. The turbine governing LVDT pull rod installation aid of claim 3, wherein: The centering block is cylindrical with a central notch. The outer diameter of the centering block is equal to that of the coil sleeve. The width of the central notch is equal to the diameter of the pull rod of the LVDT sensor. The pull rod of the LVDT sensor is inserted into the centering block in the radial direction.

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