A horizontal stacked valve connecting flange installation auxiliary device and a working method thereof

Abstract

The present application belongs to the technical field of mechanical assembly, and discloses a kind of installation auxiliary device of horizontal stacked valve connecting flange and working method thereof, to solve the defects of poor precision, difficult gap control and uneven stress of conventional flange installation butt joint.The present application sets up a kind of installation auxiliary device of valve connecting flange, the device includes connecting cover plate, full thread stud, locking piece, split hydraulic jack, the connecting cover plate and flange are connected and fastened by full thread stud, uniform horizontal pressure is applied to the surface of flange by split hydraulic jack to adjust the horizontal gap of flange, the bolt fastening mode of 3 times cross intersection and symmetrical tightening is adopted, so that the flange sealing surface is uniformly stressed, stress concentration is reduced, leakage risk is reduced, installation efficiency is improved, the whole installation method step is clear, operation is simple, without complex installation skill, installation cycle can be effectively shortened, and labor cost is reduced.

Description

Technical Field

[0001] This invention belongs to the field of mechanical assembly technology, and specifically relates to an installation auxiliary device and its working method for a horizontally stacked valve connection flange. Background Technology

[0002] The core purpose of precision alignment of turbine valve flanges is to establish the optimal initial state under cold conditions in order to ensure the absolute safety and long-term stability of the unit during high-temperature and high-pressure operation. Specifically, there are five main objectives: First, to ensure zero leakage (the primary objective), guaranteeing absolute parallelism between the two flange faces, ensuring extremely uniform pressure on the gasket, and forming a tight metal-to-metal contact. This prevents the leakage of high-temperature, high-pressure steam, avoids injury and shutdown, and is fundamental to preventing erosion damage to the sealing surface. Second, to eliminate harmful additional stress, avoiding extra stress generated by forced pulling. This prevents the brittle cast iron valve body from breaking and also avoids stress transmission to the cylinder, causing deformation or rotor misalignment and vibration. Third, to ensure flexible valve stem movement, preventing valve body deformation due to stress, which could lead to valve stem bending or loss of clearance with the valve sleeve. This avoids adjustment jamming and valve core wear, ensuring accurate speed and load control. Fourth, to meet the thermal expansion trajectory. Precise alignment in the cold state allows for the correct direction of thermal expansion. If the cold state deviation is too large, the huge thrust in the hot state will exacerbate stress, even leading to cold-drawing failure or bolt breakage. Fifth, to extend equipment life and improve economy. Uniform stress can prevent premature gasket crushing and bolt fatigue, extend maintenance cycles, and reduce the huge economic losses caused by unplanned downtime.

[0003] In existing technologies, flange installation typically relies on manual operation and crane assistance, which leads to problems such as poor alignment accuracy, difficulty in gap control, and uneven stress. These problems can cause flange seal failure, loose connections, and even safety hazards. During actual on-site installation of steam turbines, the flange installation accuracy requirements for the connection between the turbine's outer cylinder and valves are high. In many installation sites, the failure to meet the required flange installation accuracy has resulted in repeated instances of bolt seizure. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an installation auxiliary device and its working method for horizontally stacked valve connection flanges. The purpose is to solve the defects of poor installation accuracy, difficulty in gap control, and uneven stress in conventional flange installation. By improving the operation methods in the flange installation process, the device improves the flange connection accuracy, installation quality, and work efficiency, while reducing the labor intensity of operators.

[0005] To achieve the objective of this invention, the technical solution adopted is as follows: An installation auxiliary device for a horizontally stacked valve connection flange includes a connecting cover plate 1, a fully threaded stud 2, a locking component, and a split-type hydraulic jack 3; the locking component includes nut I 4, nut II 5, and two washers 6 that are matched with nut I 4 and nut II 5.

[0006] The connecting cover plate 1 is provided with a connecting hole, which corresponds to the lifting screw hole of the flange connecting bolt 10. The diameter of the connecting hole is ≥ twice the diameter of the fully threaded stud, which is used to realize the detachable connection between the installation auxiliary device and the flange.

[0007] Preferably, the number of connecting holes in the connecting cover plate 1 is ≥2; the connecting cover plate 1 has a cuboid structure.

[0008] Preferably, the connecting cover plate 1 is made of alloy steel; more preferably, the material of the connecting cover plate 1 is 40Cr or 42CrMo after quenching and tempering.

[0009] Preferably, the thickness of the connecting cover plate 1 is ≥30mm to ensure that it does not deform when subjected to the pressure of the jack.

[0010] One end of the fully threaded stud 2 is screwed into the lifting bolt hole of the flange connecting bolt 10 by the thread, and the other end passes through the connecting hole and is fixed to the connecting cover plate 1 by the locking member.

[0011] The outer diameter of the fully threaded stud 2 is compatible with the inner diameter of the lifting bolt hole of the flange connection bolt 10; the fully threaded stud is made of round steel.

[0012] The split-type hydraulic jack 3 is installed between the connecting cover plate 1 and the flange 7. The metal base of the split-type hydraulic jack 3 is tightly fitted with the end face of the connecting cover plate 1, and the piston end is aligned with the surface of the flange 7 and fits tightly. The split-type hydraulic jack 3 is used to apply uniform horizontal pressure to the flange surface to adjust the horizontal clearance of the flange.

[0013] Among them, the installation auxiliary device for the horizontally stacked valve connection flange is set in two sets symmetrically on the left and right sides with the vertical center plane of the flange as the baseline.

[0014] The operating method of the installation auxiliary device for horizontally stacked valve connection flanges includes the following steps: (1) Tighten the flange connecting bolts into the flange bolt holes of the outer cylinder of the steam turbine. Among them, the two flange connecting bolts on the left and right sides of the vertical split surface of the flange and close to the horizontal split surface are not installed. These two flange connecting bolts are symmetrical about the vertical split surface of the flange, which facilitates the placement of the hydraulic jack and the force is balanced. (2) Make preliminary connection between the flange and the flange connecting bolts of the outer cylinder of the steam turbine. Use a ruler to measure the gap between the flange and the cylinder body around the perimeter, and adjust the gap difference to ensure that the gap difference is less than 1cm. (3) Install the installation auxiliary device of the horizontal stacked valve connection flange onto the flange. Each set of installation auxiliary devices is connected to the lifting bolt hole of the flange connection bolt through the fully threaded stud. The flange connection bolt is the upper and lower corresponding two flange connection bolts that are not installed in step (1). Place the split hydraulic jack in the empty position of the flange connection bolt that is not installed. Use the locking part to fix the connection cover plate to the flange. Adjust the height of the connection cover plate so that the piston end of the split hydraulic jack is aligned with the flange surface and fits tightly. (4) Start the two-sided split hydraulic jacks and slowly apply horizontal pressure to the flange surface. During the application of force, measure the horizontal gap of the flange in real time until the horizontal gap reaches 3~4cm. Keep the pressure stable for 1~2 minutes to ensure that the flange position is fixed. (5) Disassemble the auxiliary device for installing the horizontally stacked valve connecting flange and install the remaining two flange connecting bolts; (6) After tightening the nuts III of the flange connecting bolts, use a hydraulic wrench to tighten all the nuts of the flange connecting bolts in three steps, in a cross-shaped and symmetrical tightening manner. Tighten them to 30% of the target cold tightening torque the first time, 60% of the target cold tightening torque the second time, and 100% of the target cold tightening torque the third time. (7) Use a torque wrench to check the tightening torque of all nuts to confirm that there is no looseness. At the same time, use a feeler gauge to check the flange gap value. Use 8 evenly spaced points around the circumference to ensure that the gap difference is ≤0.20mm. Then complete the flange installation.

[0015] The above technical solution has the following beneficial effects: 1. The horizontal stacked valve connection flange installation auxiliary device provided by the present invention has a simple structure and is detachable. By precisely matching the lifting bolt holes of the connecting cover plate and the flange connection bolts, the device can be quickly positioned and installed.

[0016] 2. The bolt tightening method of three-fold cross-tightening and symmetrical tightening ensures that the flange sealing surface is evenly stressed, reduces stress concentration, lowers the risk of leakage, and improves installation efficiency.

[0017] 3. The entire installation method is clear and simple to operate, requiring no complicated installation skills, which can effectively shorten the installation cycle and reduce labor costs. Attached Figure Description

[0018] Figure 1 A schematic diagram of the installation auxiliary device for horizontally stacked valve connection flanges; Figure 2 This is an installation diagram of the auxiliary installation device; Figure 3 This is a diagram showing the installation sequence of the flange connection bolts in Example 2; In the diagram: 1-Connecting cover plate, 2-Fully threaded stud, 3-Split hydraulic jack, 4-Nut I, 5-Nut II, 6-Washer, 7-Flange, 8-Outer cylinder of turbine, 9-Nut III, 10-Flange connecting bolt. Detailed Implementation

[0019] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0020] Example 1 This embodiment is based on the intermediate-pressure steam inlet flange connecting the intermediate-pressure outer cylinder of the steam turbine and the intermediate-pressure valve. Its installation auxiliary device includes: The steam turbine is a 660MW type steam turbine, in which the outer cylinder and the intermediate valve are connected through the intermediate pressure steam inlet flange. It is required that the gap between the intermediate pressure steam inlet flange and the intermediate pressure outer cylinder is 1.6mm and the circumferential gap is uniform. The diameter of the flange bolt hole is M88.

[0021] The connecting cover plate is made of 40Cr steel plate with a thickness of 30mm. There are two connecting holes on the connecting cover plate with a diameter of φ48mm. The fully threaded stud is made of round steel with an outer diameter of M24 and a length of 300mm. Nut I and Nut II are M24 nuts that match the fully threaded stud and have a thickness of 24mm. Nut I and Nut II are each equipped with a washer. The split hydraulic jack is a hydraulic jack with a rated pressure of 10t.

[0022] Example 2 This embodiment is based on the installation auxiliary device of Embodiment 1, and a total of two sets of installation auxiliary devices are set up. The installation steps of the intermediate pressure steam inlet flange connecting the intermediate pressure outer cylinder of the steam turbine and the intermediate valve are as follows: S1: Manually tighten the M88 flange connecting bolts into the bolt holes of the intermediate-pressure outer cylinder of the steam turbine. Note that the two flange connecting bolts on the left and right sides of the vertical split plane, closest to the horizontal split plane, are not installed. Figure 2 , 3 As shown, in this embodiment, #3 and #21 are not installed; S2: Use a 5t crane to lift the intermediate pressure steam inlet flange, and make preliminary connection between the intermediate pressure steam inlet flange and the M88 flange connecting bolt of the intermediate pressure outer cylinder. Use a ruler to measure the vertical distance between the flange and the cylinder body around the perimeter, and use the crane to fine-tune the flange position so that the gap difference around the perimeter is controlled within 1cm. S3: Install the horizontally stacked valve connection flange installation auxiliary device onto the medium-pressure steam inlet flange using fully threaded studs. Each installation auxiliary device is connected to the lifting bolt hole of the flange connection bolts via fully threaded studs. Figure 2 , 3As shown, in this embodiment, the flange connecting bolts that connect the fully threaded studs are the four bolts corresponding to the top and bottom of the 3# and 21# bolts that are not installed in step (1), namely the 17#, 4# and 7#, 22# bolts, which pass through the connecting hole and lifting bolt hole of the connecting cover plate through the M24 fully threaded studs. The connecting cover plate and the medium pressure steam inlet flange are fixed by the locking device. In this embodiment, the height of the connecting cover plate is adjusted to 150mm so that the piston end of the split hydraulic jack is aligned with the flange surface and fits tightly. S4: Start the two-sided split hydraulic jacks and slowly apply horizontal pressure to the surface of the medium-pressure steam inlet flange. During the application of force, measure the horizontal gap of the medium-pressure steam inlet flange in real time until the horizontal gap reaches 3.5cm. Then stop applying pressure and keep the pressure stable for 1~2 minutes. S5: Disassemble the split hydraulic jack, locking parts, connecting cover plate, and fully threaded studs in sequence, and install the remaining two #3 and #21 flange connecting bolts; S6: After manually tightening the nuts III of the flange connection bolts, use a hydraulic wrench to tighten all 24 nuts of the flange connection bolts in three stages, using a cross-shaped and symmetrical tightening method. The target torque is 3000Nm. Tighten to 1000Nm the first time, 1800Nm the second time, and 3000Nm the third time. S7: Use a torque wrench to check the tightening torque of all nuts, confirming that the torque reaches 3000Nm and there is no looseness. At the same time, use a feeler gauge to check the gap value of the intermediate pressure steam inlet flange (evenly distributed at 8 points around the circumference), ensuring that the gap difference is ≤0.20mm, and complete the installation of the intermediate pressure steam inlet flange.

[0023] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An auxiliary device for installing horizontally stacked valve connection flanges, characterized in that: It includes a connecting cover plate (1), a fully threaded stud (2), a locking component, and a split hydraulic jack (3); the locking component includes nut I (4), nut II (5) and two washers (6); the two washers (6) are respectively matched with nut I (4) and nut II (5); The connecting cover plate (1) is provided with connecting holes, which correspond to the lifting screw holes of the flange connecting bolts (10). The diameter of the connecting holes is ≥ twice the diameter of the fully threaded stud, and the number of connecting holes is ≥ 2. One end of the fully threaded stud (2) is screwed into the lifting screw hole of the flange connecting bolt (10) by the thread, and the other end passes through the connecting hole and is fixed to the connecting cover plate (1) by the locking member; the outer diameter of the fully threaded stud (2) is adapted to the inner diameter of the lifting screw hole of the flange connecting bolt (10); The split hydraulic jack (3) is set between the connecting cover plate (1) and the flange (7). The metal base of the split hydraulic jack (3) is tightly fitted with the end face of the connecting cover plate (1), and the piston end is aligned with the surface of the flange (7) and fits tightly. The installation auxiliary device is set in two sets symmetrically with the vertical split plane of the flange as the baseline.

2. The installation auxiliary device for horizontally stacked valve connection flanges according to claim 1, characterized in that: The connecting cover plate (1) has a cuboid structure.

3. The installation auxiliary device for horizontally stacked valve connection flanges according to claim 1, characterized in that: The connecting cover plate (1) is made of 40Cr or 42CrMo.

4. The installation auxiliary device for horizontally stacked valve connection flanges according to claim 1, characterized in that: The thickness of the connecting cover plate (1) is ≥30mm.

5. The installation auxiliary device for horizontally stacked valve connection flanges according to claim 1, characterized in that: The fully threaded stud (2) is made of round steel.

6. A method for operating an installation auxiliary device for a horizontally stacked valve connection flange as described in any one of claims 1-5, characterized in that the steps include... include: (1) Tighten the flange connecting bolts into the flange bolt holes of the outer cylinder of the steam turbine. The two flange connecting bolts on the left and right sides of the vertical split surface of the flange and close to the horizontal split surface are not installed. The two flange connecting bolts are symmetrical about the vertical split surface of the flange. (2) Make preliminary connection between the flange and the flange connecting bolts of the outer cylinder of the steam turbine, use a ruler to measure the gap between the flange and the cylinder body, and adjust the gap difference to be less than 1cm; (3) Install the installation auxiliary device onto the flange. Each set of installation auxiliary devices is connected to the lifting bolt hole of the flange connecting bolt through a fully threaded stud. The flange connecting bolt is the two corresponding bolts of the flange connecting bolt that are not installed in step (1). Place the split hydraulic jack in the empty position of the flange connecting bolt that is not installed. Use the locking device to fix the connecting cover plate to the flange. Adjust the height of the connecting cover plate so that the piston end of the split hydraulic jack is aligned with the flange surface and fits tightly. (4) Start the two-sided split hydraulic jacks and slowly apply horizontal pressure to the flange surface. During the application of force, measure the horizontal gap of the flange in real time until the horizontal gap reaches 3~4cm. Keep the pressure stable for 1~2 minutes to ensure that the flange position is fixed. (5) Disassemble the auxiliary device for installing the horizontally stacked valve connecting flange and install the remaining two flange connecting bolts; (6) After tightening the nuts III of the flange connecting bolts, use a hydraulic wrench to tighten all the nuts of the flange connecting bolts in three steps, in a cross-shaped and symmetrical tightening manner. Tighten them to 30% of the target cold tightening torque the first time, 60% of the target cold tightening torque the second time, and 100% of the target cold tightening torque the third time. (7) Use a torque wrench to check the tightening torque of all nuts to confirm that there is no looseness. At the same time, use a feeler gauge to check the flange gap value. Use 8 evenly spaced points around the circumference to ensure that the gap difference is ≤0.20mm. Then complete the flange installation.

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