Method and system for replacing thrust pad of suspension type water-turbine generator set

Abstract

The invention discloses a method and a system for replacing a thrust pad of a suspension type water-turbine generator set, relates to the technical field of maintenance of the suspension type water-turbine generator set, and solves the problems of large range, long time, high cost and high equipment damage risk of traditional replacement and disassembly. According to the method, small-range disassembly, cooler in-situ rotation and displacement and conventional tool cooperation are adopted, only three types of components are disassembled, the coolers on the two sides are subjected to 30-degree in-situ rotation three times, wood beams wrapped with polyethylene plastic are used for temporary supporting, two sets of thrust pads are replaced in sequence, and resetting is conducted after precise disassembly and assembly are conducted with the help of a conventional tool. The matched special system comprises a cooler shifting system and a disassembling auxiliary system. The operation time is less than or equal to 2 days, the shutdown time is reduced by 32 hours, the generating capacity of a 260MW unit is increased by 832,000 kilowatt-hours, the manpower is reduced by 50%, the equipment damage rate is 0, and the method is suitable for units with different capacities and is wide in application.

Description

Technical Field

[0001] This invention relates to the field of hydro-generator maintenance technology, specifically to a method and system for replacing thrust bearings in a suspended hydro-generator. Background Technology

[0002] The thrust bearing of a suspended hydro-generator unit is a core component bearing the axial load of the unit and needs to be replaced regularly after long-term operation to ensure the safety of the unit. In the existing technology, the replacement of thrust bearings generally adopts a "full disassembly" strategy. According to the "Technical Specification for Overhaul of Vertical Hydro-generator Unit 162" and the "Technical Specification for Overhaul of Mechanical Parts of Hydro-generator Unit Main Unit", it is necessary to remove seven types of components, including the generator cover plate, collector ring brush holder, carbon brush, thrust head, upper guide bearing holder, thrust bearing oil pan cover, and oil stabilizer plate. The disassembly scope is large and the process is complicated. At the same time, the thrust bearing cooler needs to be hoisted to the maintenance site outside the unit as a whole, which not only occupies extra space, but also requires disconnecting the cooling oil circuit and sealing the pipe openings, resulting in an operation time of more than 3 days and significant downtime losses.

[0003] Existing technologies employ a ring track, a moving frame, and an air cushion suspension device to remove the bearings. The core lies in specialized bearing removal tools and processes, without disclosing or implying a method of creating working space by rotating and relocating the cooler in situ. Existing technologies optimize the thrust bearing structure by setting up manholes and external coolers to facilitate maintenance, with the innovation lying in the change of hardware structure. Although existing technologies involve cooler movement, they use "rollers + adjusting screws" to achieve horizontal movement on the ground, requiring the cooler to be raised and surrounding pipelines to be removed, which cannot be adapted to the limited space inside suspended units.

[0004] The existing technology is characterized by "prioritizing full disassembly", "the cooler must be hoisted to the outside", and "reliance on special tools", which leads to pain points in thrust bearing replacement such as "large disassembly range, long operation time, high tool investment, and high risk of equipment damage". There is an urgent need for a breakthrough technical solution to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a method and dedicated system for replacing thrust bearings in suspended hydro-generator sets. By combining the technologies of "small-scale disassembly + in-situ rotation and relocation of the cooler + collaboration with conventional tools", it breaks through the inertia of existing technologies and achieves efficient, safe and low-cost thrust bearing replacement operations, significantly shortening downtime and reducing labor intensity.

[0006] To address the aforementioned problems, according to one aspect of this application, an embodiment of the present invention provides a method for replacing the thrust bearing of a suspended hydro-generator set, comprising the following steps:

[0007] S1: Remove the generator cover;

[0008] S2: Dismantle the thrust bearing oil mist suction device pipeline and the toner collection device pipeline;

[0009] S3: Disassemble the thrust bearing oil pan cover and oil stabilizer plate, remove the thrust bearing temperature measuring element and temperature measuring wire, and disconnect the thrust bearing cooling water pipeline.

[0010] S4: Relocate the thrust bearing cooler and replace the thrust bearing pad: Move the two thrust bearing coolers by rotating them in place three times to create working space for replacing the thrust bearing pads in different positions.

[0011] S5: Clean the oil tank and reinstall the thrust bearing;

[0012] S6: Reinstall auxiliary facilities and generator cover.

[0013] In some implementations, step S4 specifically includes:

[0014] S41: Erect a support structure above the first cooler, use a crane to lift the second cooler and rotate it in place around its own central axis in the first direction, and temporarily support it on the support structure above the first cooler.

[0015] S42: Replace the first set of thrust bearings corresponding to the space freed up due to the relocation of the second cooler;

[0016] S43: The second cooler rotates back to its installation position in the opposite direction around its own central axis;

[0017] S44: Rotate the first cooler around its own central axis in a second direction opposite to the first direction and temporarily support it on the support above the second cooler.

[0018] S45: Replace the second set of thrust bearings corresponding to the space freed up by the relocation of the first cooler;

[0019] S46: The first cooler rotates back to its installation position in the opposite direction around its own central axis.

[0020] In some embodiments, the first cooler is a left-side cooler, and the second cooler is a right-side cooler; the first direction is clockwise, and the second direction is counterclockwise.

[0021] The first set of thrust bearings includes a first thrust bearing and a second thrust bearing, and the second set of thrust bearings includes a third thrust bearing and a fourth thrust bearing;

[0022] The cooler can rotate in situ at an angle of 30°, and does not leave the internal space defined by the unit frame during the rotation.

[0023] In some embodiments, the support is a piece of wood wrapped with a layer of polyethylene plastic;

[0024] The cross-sectional dimensions of the timber are 100mm × 100mm, and its length is 200mm longer than the width of the thrust oil groove.

[0025] The timber should be arranged radially along the axis of the cooler, with a minimum of two pieces;

[0026] The contact area between the timber and the thrust head and the collector ring brush holder shall not be less than 50 cm².

[0027] In some embodiments, the operation of replacing the thrust bearing in step S4 includes:

[0028] Using a hydraulic lifting trolley with a rated load of 5t and a lifting accuracy of ±0.5mm, adjust its working plane to be flush with the bearing plane of the thrust bearing to be replaced;

[0029] Use a 5kg pull rod with a 20mm diameter to pull the thrust bearing horizontally from its installation position and transfer it to the hydraulic lifting trolley.

[0030] The old thrust bearings are transported to the installation room by a crane and a hydraulic lifting trolley, and the new thrust bearings are transported to the hydraulic lifting trolley in the oil tank.

[0031] The new thrust bearing is aligned with its installation position using a hydraulic lifting trolley and then slowly pushed into the installation position.

[0032] In some implementations, when removing the generator cover in step S1, the generator cover plate, slip ring brush holder, and carbon brushes are not removed.

[0033] This invention also provides a suspension-type hydro-generator thrust bearing replacement system for performing any of the methods described above, including:

[0034] Temporary support device: includes at least two wooden blocks, the wooden blocks are wrapped with a polyethylene plastic layer, arranged radially along the axis of the cooler body, the top is attached to the bottom of the cooler body, the bottom is in contact with the thrust head and brush holder, the cross-sectional size is 100mm×100mm, and the length is 200mm longer than the width of the thrust oil groove.

[0035] Lifting equipment: configured to hoist the cooler and assist it in completing a 30° in-situ rotation around its own central axis.

[0036] Compared with the prior art, the method and system for replacing thrust bearings of suspended hydro-generator sets of the present invention have at least the following beneficial effects:

[0037] Minimize the scope of disassembly: Only three types of components are disassembled, reducing the amount of disassembly by 57% compared to the traditional solution. Larger components such as generator cover plates and collector ring brush frames are not removed. By clearly defining the steps of "not disassembling the thrust cooler, but only relocating to make room for the work", it completely distinguishes itself from the traditional full disassembly process and breaks through the inertia of technology.

[0038] Reduced equipment damage rate: By using protected timber as support components, the equipment damage rate is reduced to zero.

[0039] In-situ reuse of space for coolers: The cooler is moved by rotating 30° in-situ, which is completely different from the existing technology of "lifting the whole unit to the outside". The operation time of a single unit cooler is shortened by 8-12 hours.

[0040] Efficiency and benefits are significantly improved: the operation time is shortened to within 2 days, reducing downtime by 32 hours compared to the traditional solution; taking a 260MW unit as an example, the power generation increases by 8.32 million kWh (calculated based on: 260MW×32h=8320MWh), and based on the industry average on-grid electricity price of 0.22 yuan / kWh, the output value increases by 1.8304 million yuan (8,320,000kWh×0.22 yuan / kWh=1,830,400 yuan); the manpower requirement is reduced from 20 people to 10 people, reducing costs by 50%.

[0041] High tool versatility: It adopts conventional tools such as hydraulic lifting trolleys and pull rods and slide weights, eliminating the need for customized ring rails or special transfer devices, reducing tool investment costs, and adapting to the existing maintenance equipment configuration of hydropower stations.

[0042] The technologies are combined and inseparable: small-scale disassembly provides the space for the in-situ rotation of the cooler, the relocation of the cooler creates a working surface for the replacement of the thrust bearing, and the special positioning components ensure the accuracy of the relocation. The three form a closed loop, which is not a simple superposition of technologies.

[0043] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0044] Figure 1 : Generator thrust bearing structure diagram;

[0045] Figure 2 Schematic diagram of thrust bearing cooler relocation;

[0046] Figure 3 : Schematic diagram of thrust bearing location;

[0047] Figure 4 Top view of the timber support location;

[0048] Figure 5Side view of the timber support location;

[0049] Explanation of reference numerals in the attached figures:

[0050] 1. Generator hood; 2. Oil mist suction device piping; 3. Carbon powder collection device piping; 4. Oil pan cover; 5. Oil stabilizer plate; 6. Thrust bearing cooling water piping; 7. Left side cooler; 8. Right side cooler; 9. Clockwise direction; 10. Counterclockwise direction; 11. First thrust bearing; 12. Third thrust bearing; 13. Fourth thrust bearing; 14. Second thrust bearing; 15. Timber; 16. Thrust head; 17. Generator cover plate; 18. Carbon brush; 19. Collector ring brush holder. Detailed Implementation

[0051] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the specific embodiments, structures, features, and effects according to the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments. In the following description, different "an embodiment" or "an embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0052] In the description of this invention, it should be clearly stated that the terms "first," "second," etc., in the specification, claims, and accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence; the terms "vertical," "lateral," "longitudinal," "front," "rear," "left," "right," "up," "down," "horizontal," etc., indicate orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, and are merely for the convenience of describing this invention, and do not mean that the device or element referred to must have a specific orientation or position, and therefore should not be construed as a limitation of this invention.

[0053] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0054] like Figure 1-5 As shown in the figure, this embodiment of the invention provides a method for replacing the thrust bearing of a suspended hydro-generator unit, including the following steps:

[0055] S1: Remove generator cover 1;

[0056] S2: Dismantle the thrust bearing oil mist suction device pipeline 2 and the carbon powder collection device pipeline 3;

[0057] S3: Disassemble the thrust bearing oil pan cover 4 and oil stabilizer plate 5, remove the thrust bearing temperature measuring element and temperature measuring wire, and disconnect the thrust bearing cooling water pipeline 6.

[0058] S4: Relocate the thrust bearing cooler and replace the thrust bearing pad: Move the two thrust bearing coolers by rotating them in place three times to create working space for replacing the thrust bearing pads in different positions.

[0059] S5: Clean the oil tank and reinstall the thrust bearing;

[0060] S6: Reinstall auxiliary facilities and generator cover 1.

[0061] In this embodiment, the unit is first prepared for maintenance. After the unit is switched to maintenance mode, the thrust bearing inlet valve is closed and the outlet valve is opened to drain the turbine oil from the thrust oil sump. Then, the generator cover 1 is removed. The elastic clips at the bottom of the generator cover 1 are used to separate it from the unit frame flange. A crane is then used to smoothly lift the generator cover 1 away. During this process, the generator cover plate 17, the slip ring brush holder 19, and the carbon brush 18 remain stationary, and their connecting bolts remain tightened. Next, the thrust bearing oil mist suction device pipeline 2 and the carbon powder collection device pipeline 3 are removed to avoid pipeline interference during subsequent operations. Then, the thrust bearing oil pan cover 4 and the oil stabilizing plate 5 are disassembled, the corresponding fixing bolts are unscrewed, the sealing gasket is removed and properly placed, and the thrust bearing temperature measuring element and temperature measuring wire are removed. After cleaning the remaining turbine oil in the oil sump, the thrust bearing cooling water pipeline 6 is disconnected, creating the necessary conditions for cooler relocation and thrust bearing replacement.

[0062] The core steps are relocating the coolers and replacing the thrust bearings. The two thrust bearing coolers are moved by rotating them in place three times to make room for operation: First, a special support is erected above one of the coolers. The other cooler is lifted by a crane and rotated in place around its own central axis in a specific direction, temporarily supported on the erected support. At this time, the space freed up is used to replace the corresponding set of thrust bearings. After the replacement is completed, the cooler is rotated in the opposite direction and moved back to its original position and fixed. Then, the other cooler is moved according to the same logic, and another set of thrust bearings is replaced. Finally, the second cooler is also moved back to its original position.

[0063] After all thrust bearings have been replaced, the oil tank is thoroughly cleaned to remove any remaining impurities and oil stains, ensuring a clean reinstallation environment. Next, the cooler is reinstalled, the cooling water pipes are precisely connected, and the thrust bearing temperature sensing elements and wires are installed. The oil stabilizer plate 5 and oil pan cover 4 are then repositioned, the fixing bolts are tightened, and the sealing gasket is ensured to be in place. Finally, the oil mist suction device and carbon powder collection device are reinstalled, and the generator cover 1 is re-hoisted into place and securely fastened to the unit frame flange using elastic clamps, completing the entire operation process.

[0064] This method optimizes the disassembly process, removing only necessary components, thus avoiding the cumbersome procedures of traditional full disassembly and significantly shortening the operation time and unit downtime. The in-situ rotation and relocation of the cooler eliminates the need to transport it to an external site, reducing pipeline disassembly and sealing work, lowering the risk of equipment damage, and allowing the operation to be completed with conventional tools without the need for additional customized equipment, significantly reducing labor input and operating costs.

[0065] In some implementations, step S4 specifically includes:

[0066] S41: Erect a support structure above the first cooler, use a crane to lift the second cooler and rotate it in place around its own central axis in the first direction, and temporarily support it on the support structure above the first cooler.

[0067] S42: Replace the first set of thrust bearings corresponding to the space freed up due to the relocation of the second cooler;

[0068] S43: The second cooler rotates back to its installation position in the opposite direction around its own central axis;

[0069] S44: Rotate the first cooler around its own central axis in a second direction opposite to the first direction and temporarily support it on the support above the second cooler.

[0070] S45: Replace the second set of thrust bearings corresponding to the space freed up by the relocation of the first cooler;

[0071] S46: The first cooler rotates back to its installation position in the opposite direction around its own central axis.

[0072] In this embodiment, after completing the initial disassembly preparation, at least two supports are erected radially above the first cooler along its axis, with both ends of the supports making stable contact with the thrust head 16 and the collector ring brush holder 19, respectively. The second cooler is then lifted using a crane, controlling the lifting force to avoid overload. Simultaneously, the cooler is rotated in place around its central axis along the first direction, with close observation of the distance between the cooler and surrounding components during rotation to ensure no interference occurs. Finally, it is temporarily supported on the supports above the first cooler and secured with positioning components. The space freed up by the repositioned second cooler is then fully exposed. The hydraulic lifting trolley is pushed into this space, and the trolley's working plane is adjusted to be flush with the bearing plane of the first set of thrust bearings to be replaced. A pull rod and sliding hammer are used to connect the side lifting rings of the thrust bearings, applying a uniform axial force to pull the thrust bearings horizontally and smoothly transfer them onto the hydraulic lifting trolley. Through the coordinated operation of the crane and the hydraulic lifting trolley, the old thrust bearings are transported to the installation room, and the new thrust bearings are then lifted onto the hydraulic lifting trolley in the oil tank. After the new thrust bearing is in place, adjust the height and position of the hydraulic lifting trolley to ensure precise alignment between the thrust bearing positioning hole and the thrust bearing support positioning pin. Then, slowly push the new thrust bearing into the installation position, ensuring the fit clearance meets the requirements. After the first set of thrust bearings is replaced, start the crane to lift the second cooler, which is temporarily supported, and rotate it in the opposite direction around its own central axis, gradually moving it back to the initial installation position. Adjust the cooler to ensure precise connection between the oil inlet and outlet pipes and the external oil circuit, insert the positioning pin to fix it, and remove the support. Next, following the same steps as above, erect a support above the second cooler, rotate the first cooler in the opposite direction around its own central axis, and temporarily support it on the support above the second cooler and fix it. Use the space freed up to replace the second set of thrust bearings. The replacement operation is exactly the same as the first set of thrust bearings, ensuring that the new bearings are installed accurately and securely. After the second set of thrust bearings is installed, rotate the first cooler in the opposite direction and move it back to its original position, connect the pipeline and fix it, completing the cooler relocation and replacement of all thrust bearings. This process maximizes the use of idle space inside the unit by moving the unit in stages and alternating operations, avoiding the space occupation and time consumption caused by hoisting the entire cooler. Each operation has clear positioning and support to ensure the stability of the cooler relocation process and the precision of the thrust bearing installation and removal. This effectively reduces the risk of equipment collision and damage during operation, while significantly improving work efficiency and shortening the replacement cycle of a single set of thrust bearings.

[0073] In some embodiments, the first cooler is the left cooler 7, and the second cooler is the right cooler 8; the first direction is clockwise 9, and the second direction is counterclockwise 10.

[0074] The first set of thrust bearings includes a first thrust bearing 11 and a second thrust bearing 14, and the second set of thrust bearings includes a third thrust bearing 12 and a fourth thrust bearing 13;

[0075] The cooler rotates in situ at an angle of 30°, and does not leave the internal space defined by the collector ring brush holder 19 during the rotation.

[0076] In this embodiment, during operation, the first cooler is clearly defined as the left cooler 7, the second cooler is the right cooler 8, the first direction is set as clockwise 9, the second direction is set as counterclockwise 10, the first set of thrust bearings includes the first thrust bearing 11 and the second thrust bearing 14, the second set of thrust bearings includes the third thrust bearing 12 and the fourth thrust bearing 13, the angle of in-situ rotation of the cooler is strictly controlled to 30°, and during the rotation process, it never leaves the internal space defined by the unit frame.

[0077] During operation, wooden supports are first erected above the left-side cooler 7. A crane lifts the right-side cooler 8 and rotates it 30° clockwise around its central axis. At this point, part of the right-side cooler 8 is moved above the left-side cooler 7 and secured using pre-set positioning holes on the unit frame and positioning pins on the side of the cooler. The positioning holes are evenly distributed around the circumference of the frame, with the central angle of adjacent holes exactly 30°, ensuring precise positioning after the cooler rotates. Using the space freed up by the relocation of the right-side cooler 8, the replacement of the first thrust bearing 11 and the second thrust bearing 14 is successfully completed.

[0078] After replacing the first set of thrust bearings, rotate the right-side cooler 8 counterclockwise 30° to its original position, insert the positioning pin to fix it, and remove the supporting timber above the left-side cooler 7. Then, erect supporting timber above the right-side cooler 8, lift the left-side cooler 7, and rotate it counterclockwise 30° around its own central axis to partially move it above the right-side cooler 8. Similarly, fix it by using positioning pins to engage with the corresponding positioning holes. At this point, the space on the left side is freed up, and the third thrust bearing 12 and the fourth thrust bearing 13 can be replaced.

[0079] The 30° rotation angle is precisely calculated to ensure sufficient space for thrust bearing installation and removal after the cooler is moved, while avoiding collisions and interference between the cooler and components such as the unit frame and oil tank due to excessive rotation angle. The clear distinction between left and right coolers and the clockwise and counterclockwise rotation directions make the operation process more standardized and operable. The correspondence between different sets of thrust bearings and the cooler relocation direction ensures that all target thrust bearings can be replaced within the optimal working space, improving the overall orderliness and efficiency of the operation.

[0080] In some embodiments, the support is a wooden block 15 wrapped with a polyethylene plastic layer;

[0081] The cross-sectional dimensions of the timber 15 are 100mm × 100mm, and its length is 100mm longer than that of the cooler body.

[0082] Timber 15 is arranged radially along the axis of the cooler, with a minimum quantity of two pieces;

[0083] The contact area between the timber 15, the thrust head 16, and the collector ring brush holder 19 shall not be less than 50 cm².

[0084] In this embodiment, the support is a 100mm × 100mm timber strip 15. The length of the timber strip 15 is 200mm longer than the width of the thrust oil groove, ensuring that both ends of the timber strip 15 extend beyond the thrust oil groove to form a stable support span. To prevent sawdust from falling into the oil groove and contaminating the oil, thus affecting the operation of the unit, the timber strip 15 is wrapped with a layer of polyethylene plastic. The plastic layer is tightly attached to the surface of the timber strip 15 without damage or wrinkles.

[0085] When arranging the timbers 15, place them radially parallel to the axis of the cooler body, with at least two timbers. Maintain a reasonable distance between the two timbers 15 to ensure that the bottom of the cooler is evenly stressed. The contact area between the bottom of the timber 15 and the thrust head 16 and the collector ring brush holder 19 should not be less than 50 cm². By increasing the contact area, the weight load of the cooler can be distributed, preventing the timbers 15 from sinking into the bottom of the oil pan or damaging the oil pan structure due to excessive local pressure.

[0086] Before relocating the cooler, place the wooden blocks 15, wrapped with polyethylene plastic, in the designated positions and quantities in the target support area. Adjust the wooden blocks 15 to ensure their tops are level and that they fully fit against the bottom of the cooler body. After the crane lifts the cooler and rotates it to the predetermined position, slowly place the cooler on the wooden blocks 15. Once it is confirmed that the cooler is stably supported and not tilted, release the crane hook to proceed with the subsequent thrust bearing replacement work.

[0087] This size of timber (15mm) has sufficient strength and load-bearing capacity to stably support the weight of the cooler and prevent it from falling or shifting during relocation. The polyethylene plastic wrapping effectively isolates wood dust contamination. The reasonable arrangement and contact area requirements further enhance the stability and safety of the support, providing a reliable foundation for the in-situ rotation and relocation of the cooler, and ensuring that the entire operation is smooth and controllable.

[0088] In some embodiments, the operation of replacing the thrust bearing in step S4 includes:

[0089] Using a hydraulic lifting trolley with a rated load of 5t and a lifting accuracy of ±0.5mm, adjust its working plane to be flush with the bearing plane of the thrust bearing to be replaced;

[0090] Use a 5kg pull rod with a 20mm diameter to pull the thrust bearing horizontally from its installation position and transfer it to the hydraulic lifting trolley.

[0091] The old thrust bearings are transported to the installation room by a crane and a hydraulic lifting trolley, and the new thrust bearings are transported to the hydraulic lifting trolley in the oil tank.

[0092] The new thrust bearing is aligned with its installation position using a hydraulic lifting trolley, so that the thrust bearing positioning hole engages with the thrust bearing support positioning pin, and is then slowly pushed into the installation position.

[0093] In this embodiment, when replacing the thrust bearing, a hydraulic lifting trolley with a rated load of 5t and a lifting accuracy of ±0.5mm is first selected. The trolley is pushed to the bottom of the thrust bearing to be replaced, the lifting function of the trolley is activated, and the working plane on the top of the trolley is adjusted to make it completely flush with the bearing plane of the thrust bearing to be replaced. The error is controlled within the allowable range to ensure that the thrust bearing can be moved out of the installation position smoothly.

[0094] Then, using a 5kg pull rod with a 20mm diameter, the pull rod of the pull rod is securely connected to the lifting ring on the side of the thrust bearing. The operator applies a uniform axial force to pull the thrust bearing horizontally out of its installation position. During the pulling process, the speed is controlled to be uniform to avoid deformation of the thrust bearing or damage to the internal structure of the oil tank due to uneven force. After the thrust bearing is fully pulled out, it falls smoothly onto the hydraulic lifting trolley.

[0095] Through the coordinated operation of a crane and a hydraulic lifting trolley, the trolley carrying the old thrust bearings is moved to the edge of the oil tank, and then the crane lifts the old thrust bearings off the trolley and transports them to the installation room for testing or storage; at the same time, the new thrust bearings are lifted by the crane onto the hydraulic lifting trolley in the oil tank, ensuring that the new thrust bearings are placed stably and centered on the trolley.

[0096] Adjust the height and horizontal position of the hydraulic lifting trolley to ensure that the positioning holes on the new thrust bearing are precisely aligned with the positioning pins on the oil pan. After alignment, the operator slowly pushes the hydraulic lifting trolley to smoothly push the new thrust bearing into the installation position. During the pushing process, observe the fit between the new thrust bearing and the surrounding components to ensure that there is no jamming or collision, until the new thrust bearing is fully installed and fits tightly against the installation surface.

[0097] This operation utilizes a high-precision, high-load-bearing hydraulic lifting trolley to ensure precise height control during the installation and removal of the thrust bearing. The use of a dedicated pull rod and sliding hammer makes the thrust bearing removal operation easier and smoother, preventing damage to the bearing body. The coordinated operation of the crane and the hydraulic lifting trolley improves the transportation efficiency and safety of both new and old thrust bearings. The precise alignment of the positioning holes and positioning pins ensures the accuracy of the new thrust bearing installation, effectively improving the quality and efficiency of thrust bearing replacement and extending the stability of the unit's operation.

[0098] In some embodiments, when removing the generator cover 1 in step S1, the generator cover plate 17, the collector ring brush holder 19, and the carbon brush 18 are not removed.

[0099] In this embodiment, when removing the generator cover 1, the principle of not removing the generator cover plate 17, the slip ring brush holder 19, and the carbon brushes 18 is strictly followed. The connecting bolts between the generator cover plate 17 and the unit frame are kept tight to avoid damage, contamination, or displacement of internal components due to loosening or disassembly of the cover plate. The generator cover 1 is engaged with the unit frame flange by four elastic claws evenly distributed along the flange circumference. The elastic claws are made of high-strength material and have good elasticity and wear resistance.

[0100] During dismantling, operators should individually manipulate the elastic claws at the bottom of the generator cover 1 to disengage them from the slots on the generator frame flange, ensuring a minimum engagement depth of 15mm. This prevents premature loosening due to shallow engagement or difficulty in dismantling due to excessive engagement. Apply even force when manipulating the claws to avoid deformation or breakage. Simultaneously, use a crane to lift the pre-set lifting lugs on the top of the generator cover 1 at a speed controlled at ≤0.5m / s, smoothly lifting the generator cover 1 off the generator frame and placing it in a safe area next to the generator to prevent collisions with the generator or other equipment.

[0101] This connection method and dismantling requirements ensure both the robustness and sealing of the generator cover 1 during installation and simplify the dismantling process, eliminating the need for complex bolt removal operations and significantly shortening the dismantling time of the generator cover 1. The design of not removing the generator cover plate 17, slip ring brush holder 19, and carbon brush 18 reduces the number of disassembled parts, lowers the risk of damage to these vulnerable parts during dismantling and reassembly, and avoids the calibration work of reinstalling parts after dismantling, further improving overall operational efficiency and ensuring the reliability of the unit's subsequent operation.

[0102] This invention also provides a suspension-type hydro-generator thrust bearing replacement system for performing any of the methods described above, including:

[0103] Temporary support device: includes at least two wooden beams 15, the wooden beams 15 are wrapped with polyethylene plastic layer, arranged radially along the axis of the cooler body, the top of which is attached to the bottom of the cooler body, the bottom of which is in contact with the thrust head 16 and the collector ring brush frame 19, the cross-sectional size is 100mm×100mm, and the length is 200mm larger than the width of the thrust oil groove.

[0104] Lifting equipment: configured to hoist the cooler and assist it in completing a 30° in-situ rotation around its own central axis.

[0105] In this embodiment, the system mainly consists of a temporary support device and lifting equipment. The components work together to achieve precise relocation and stable support of the cooler, providing a reliable guarantee for thrust bearing replacement. The cooler assembly includes a left cooler 7 and a right cooler 8 symmetrically arranged on both sides of the thrust bearing oil pan. Both coolers have identical structures, each including a cooler body, an oil inlet pipe, and an oil outlet pipe. The oil inlet and outlet pipes extend radially along the cooler body, maintaining communication with the external oil circuit to ensure smooth flow of cooling oil. The cooler body axis is parallel to the horizontal direction, adapting to the internal spatial layout of the unit. The temporary support device uses at least two wooden beams 15, with the wooden beams 15 wrapped in a polyethylene plastic layer to effectively prevent sawdust from falling and contaminating the oil pan. Timber 15 has a cross-sectional dimension of 100mm × 100mm, and its length is 200mm longer than the width of the thrust oil groove. It is arranged radially along the axis of the cooler body, with its top fully fitting the bottom of the cooler body and its bottom making stable contact with the thrust head 16 and the collector ring brush frame 19. Through reasonable size design and arrangement, it provides a stable support foundation for the cooler relocation and distributes the weight load of the cooler. The lifting equipment is specially configured for lifting the cooler. Its lifting force and operating precision are precisely matched, which can smoothly lift the cooler and assist it in completing a 30° in-situ rotation around its own central axis. During the rotation, the lifting speed and force are controlled to avoid collisions and interference between the cooler and surrounding components, ensuring a smooth and controllable relocation process. In use, one cooler is first lifted and rotated 30° using the lifting equipment and positioning components. It is then supported and fixed using a temporary support device to create working space for replacing the corresponding thrust bearing. After replacement, the lifting equipment rotates the cooler in the opposite direction to reset it. The same process is then followed to relocate the other cooler and replace the other set of thrust bearings. The entire system has strong compatibility among its components, is easy to operate, requires no modification to the original structure of the unit, can effectively utilize the internal space of the unit, significantly shorten the cooler relocation time, reduce the workload, and improve the efficiency and safety of thrust bearing replacement.

[0106] The following are specific embodiments of the present invention:

[0107] Example: Thrust bearing replacement of a 260MW suspended hydro-generator unit (model: SF260-40 / 10500)

[0108] Disassembly preparation: The unit is shut down and put into maintenance mode. The thrust bearing oil inlet valve is closed and the thrust bearing oil outlet valve is opened to drain the turbine oil in the oil pan.

[0109] Tools required: hydraulic lifting trolley (rated load 5t, lifting accuracy ±0.5mm), pull rod slide weight (weight 5kg, pull rod diameter 20mm), 15 pieces of timber (100mm×100mm×1200mm, wrapped with 0.5mm thick polyethylene plastic layer), torque wrench (range 0-50N・m), 500V megohmmeter, hydraulic pressure testing device.

[0110] Disassembly operation

[0111] Remove generator cover 1: Manually operate the four elastic claws to disengage them from the flange of the unit frame (clamping depth 15mm), and use a crane to lift generator cover 1 to the side of the unit (select the pre-set lifting lugs on the top of generator cover 1 as the lifting point, and lift at a speed ≤0.5m / s).

[0112] Remove the thrust bearing oil pan cover 4: Use a torque wrench to unscrew the fixing bolts (specification M20×40) of the oil pan cover 4, lift the oil pan cover 4, take out the oil-resistant rubber sealing gasket (size 20mm×5mm×5mm) in the positioning groove (depth 5mm, width 20.5mm), and place it on a clean rubber pad;

[0113] Remove oil stabilizer plate 5: Use a torque wrench to unscrew the six M16×30 bolts (tightening torque 30 N・m), remove oil stabilizer plate 5 (thickness 10 mm, diameter 800 mm) from the oil basin, check that oil stabilizer plate 5 is not deformed or damaged, and then place it on a special bracket.

[0114] Disconnect the thrust bearing cooler piping.

[0115] Cooler relocation and tile replacement

[0116] Relocation of the right cooler 8: Place two wooden blocks 15 radially along the cooler axis at the bottom of the left cooler 7 (the wooden blocks 15 are spaced 300mm apart, and both ends of the wooden blocks 15 extend 200mm beyond the cooler body). Use a crane to lift the right cooler 8 (the lifting force is controlled at 1000kg to avoid overload). Rotate it 30° clockwise around its own central axis to move the left side of the cooler to above the left cooler 7 (space height 200mm). After checking that the cooler is placed stably without slippage, release the crane hook.

[0117] Replace the first thrust bearing 11: Push the hydraulic lifting trolley to the bottom of the first thrust bearing 11, adjust the height of the trolley so that the top support surface is in contact with the bottom of the first thrust bearing 11 (gap ≤ 0.1mm), connect the lifting ring on the side of the first thrust bearing 11 with the pull rod and slide hammer, apply axial force (about 500N) to pull the first thrust bearing 11 out horizontally (pulling speed 50mm / s), and transfer it to the hydraulic lifting trolley;

[0118] The old tiles are transported to the installation room by the cooperation of a crane and a hydraulic lifting trolley, and the new tiles (model: elastic metal plastic tile, size: 600mm×300mm×50mm) are transported to the hydraulic lifting trolley in the oil tank.

[0119] Adjust the height of the hydraulic lifting trolley so that the positioning hole of the new bearing (12mm in diameter) is aligned with the positioning pin of the thrust bearing bracket (11.9mm in diameter), and slowly push it into the installation position with a clearance of ≤0.1mm.

[0120] Reset the right cooler 8: Pull out the positioning pin, start the crane to lift the right cooler 8, rotate it counterclockwise 30° to reset it, adjust the position of the cooler so that the water inlet pipe, water outlet pipe and oil circuit interface are aligned, insert the positioning pin to fix it, and after checking that the cooler is not offset, remove the wooden block 15.

[0121] Left cooler 7 relocation and replacement of first thrust bearing 11 and second thrust bearing 14: Repeat the above steps of relocating right cooler 8 and replacing bearing body, only changing the rotation direction to counterclockwise, replacing third thrust bearing 12 and fourth thrust bearing 13, and placing wooden blocks 15 at the bottom of right cooler 8 to ensure stable support after left cooler 7 is relocated.

[0122] The method of the present invention is applicable to thrust bearing replacement at all locations, not limited to the first thrust bearing 11, the second thrust bearing 14, the third thrust bearing 12, and the fourth thrust bearing 13.

[0123] Reset operation

[0124] Install oil stabilizer plate 5: Align the positioning hole of oil stabilizer plate 5 with the positioning pin at the bottom of the oil pan, and screw in six M16×30 bolts in sequence. Tighten them evenly to 30 N·m in three stages using a torque wrench (tighten to 10 N·m the first time, to 20 N·m the second time, and to 30 N·m the third time).

[0125] Install oil pan cover 4: Insert the oil-resistant rubber gasket into the positioning groove, ensuring that the gasket is not twisted or damaged, cover the oil pan cover 4, and tighten the fixing bolts. The bolt tightening torque is 45 N·m.

[0126] Install generator cover 1: Align the elastic claws at the bottom of generator cover 1 with the frame flange, press the claws to a engagement depth of 15mm, and check that the claws are fully engaged to complete the installation of generator cover 1.

[0127] Inspection and trial operation

[0128] Testing the insulation resistance of the thrust tile: Using a 500V megohmmeter, measure the insulation resistance of each new thrust tile. The measured value should be ≥10MΩ, which meets the requirements of NB / T11558-2024 "Installation Specification for Elastic Metal Plastic Tiles".

[0129] Test the oil pan seal: Introduce 0.3MPa of oil pressure into the oil pan using an oil pressure testing device, maintain the pressure for 30 minutes, and observe whether there is any leakage at the oil pan flange and cooler interface;

[0130] Trial operation: The unit ran under no-load for 2 hours. The temperature of the thrust bearing was ≤55℃, the temperature difference between the inlet and outlet oil of the cooler was ≤8℃, and the vibration value of the unit was ≤0.03mm. The operation was normal.

[0131] Parameters based on instructions

[0132] The selection of timber beam 15 dimensions is based on the following: A single cooler weighs approximately 800 kg, with two timber beams 15 sharing the load. Each timber beam 15 bears 400 kg. The cross-sectional area of ​​timber beam 15 is 100 mm × 100 mm = 10000 mm² = 0.01 m². The bearing pressure is 400 kg × 9.8 N / kg ÷ 0.01 m² = 392000 Pa = 0.392 MPa, which is far less than the allowable stress of timber beam 15 (≥10 MPa), thus meeting the load-bearing requirements.

[0133] The determination of the 30° rotation angle of the cooler: Based on the internal space dimensions of the unit (the height of the unused space above the cooler is 200mm, and the radius of the cooler is 500mm), the 30° rotation angle is determined by geometric calculation to ensure that the cooler will not interfere with the surrounding components after being moved, while freeing up enough space (≥300mm) for the replacement of the thrust bearing.

[0134] The 30° center angle of the positioning hole is designed to match the rotation angle of the cooler, ensuring that the positioning pin can be accurately inserted into the adjacent positioning hole after rotation, thus achieving reliable positioning of the cooler. The fit clearance of 0.05-0.1mm can balance positioning accuracy and installation convenience.

[0135] Industrial applicability

[0136] This invention has been successfully applied to the thrust bearing replacement work of 260MW and 300MW suspended turbine generator units in three hydropower stations. Practical data shows that the operation time was reduced from 72 hours using the traditional method to less than 48 hours, downtime was reduced by 32 hours, labor costs were reduced by 50%, equipment damage rate was 0%, and the cumulative direct economic benefits exceeded 5 million yuan. This method and system do not require modification of the original generator unit structure, are adaptable to suspended turbine generator units of different capacities, have highly versatile tools, and standardized operating procedures, demonstrating broad industrial application prospects.

[0137] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the devices, apparatuses, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0138] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for replacing thrust bearings in a suspended hydro-generator unit, characterized in that, Includes the following steps: S1: Remove the generator cover (1); S2: Dismantle the thrust bearing oil mist suction device pipeline (2) and the carbon powder collection device pipeline (3). S3: Disassemble the thrust bearing oil pan cover (4) and oil stabilizer plate (5), remove the thrust bearing temperature measuring element and temperature measuring wire, and disconnect the thrust bearing cooling water pipeline (6). S4: Relocate the thrust bearing cooler and replace the thrust bearing pad: Move the two thrust bearing coolers by rotating them in place three times to create working space for replacing the thrust bearing pads in different positions. S5: Clean the oil tank and reinstall the thrust bearing; S6: Reinstall auxiliary facilities and generator cover (1).

2. The method according to claim 1, characterized in that, Step S4 specifically includes: S41: Erect a support structure above the first cooler, use a crane to lift the second cooler and rotate it in place around its own central axis in the first direction, and temporarily support it on the support structure above the first cooler. S42: Replace the first set of thrust bearings corresponding to the space freed up due to the relocation of the second cooler; S43: The second cooler rotates back to its installation position in the opposite direction around its own central axis; S44: Rotate the first cooler around its own central axis in a second direction opposite to the first direction and temporarily support it on the support above the second cooler. S45: Replace the second set of thrust bearings corresponding to the space freed up by the relocation of the first cooler; S46: The first cooler rotates back to its installation position in the opposite direction around its own central axis.

3. The method according to claim 2, characterized in that: The first cooler is the left cooler (7), and the second cooler is the right cooler (8); the first direction is clockwise (9), and the second direction is counterclockwise (10); The first set of thrust bearings includes a first thrust bearing (11) and a second thrust bearing (14), and the second set of thrust bearings includes a third thrust bearing (12) and a fourth thrust bearing (13). The cooler rotates in situ at an angle of 30°, and does not leave the internal space defined by the collector ring brush holder (19) during the rotation.

4. The method according to claim 2, characterized in that: The support is a wooden block (15) wrapped with a polyethylene plastic layer; The cross-sectional dimensions of the timber (15) are 100mm×100mm, and its length is 200mm longer than the width of the thrust oil groove. The timber (15) is arranged radially along the axis of the cooler, with a minimum of two pieces; The contact area between the timber (15) and the thrust head (16) and the collector ring brush holder (19) shall not be less than 50 cm².

5. The method according to claim 1, characterized in that, The operation of replacing the thrust bearing in step S4 includes: Using a hydraulic lifting trolley with a rated load of 5t and a lifting accuracy of ±0.5mm, adjust its working plane to be flush with the bearing plane of the thrust bearing to be replaced; Use a 5kg pull rod with a 20mm diameter to pull the thrust bearing horizontally from its installation position and transfer it to the hydraulic lifting trolley. The old thrust bearings are transported to the installation room by a crane and a hydraulic lifting trolley, and the new thrust bearings are transported to the hydraulic lifting trolley in the oil tank. The new thrust bearing is aligned with its installation position using a hydraulic lifting trolley and then slowly pushed into the installation position.

6. The method according to claim 1, characterized in that: When removing the generator cover in step S1, do not remove the generator cover plate (17), collector ring brush holder (19) and carbon brush (18).

7. A thrust bearing replacement system for a suspended hydro-generator unit, used to perform the method described in any one of claims 1-6, characterized in that, include: Temporary support device: includes at least two wooden beams (15), the wooden beams (15) are wrapped with a polyethylene plastic layer, arranged radially along the axis of the cooler body, the top is attached to the bottom of the cooler body, the bottom is in contact with the thrust head (16) and the collector ring brush frame (19), the cross-sectional size is 100mm×100mm, and the length is 200mm longer than the width of the thrust oil groove. Lifting equipment: configured to hoist the cooler and assist it in completing a 30° in-situ rotation around its own central axis.

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