Turbo-pump overspeed test method

Abstract

The application discloses a kind of steam-driven pump overspeed test methods, comprising the following steps: S1, start steam-driven pump, flow is adjusted to first preset value;S2, the connecting rod of admission regulating valve is pulled down by lever method, the opening of the admission regulating valve is increased, and steam-driven pump mechanical overspeed test is executed;S3, start steam-driven pump, flow is adjusted to second preset value;S4, the connecting rod of admission regulating valve is pulled down by lever method, the opening of the admission regulating valve is increased, and steam-driven pump electromagnetic overspeed test is executed.The steam-driven pump overspeed test method of the application uses lever principle, and the opening of admission regulating valve is increased by lever method, so as to increase the steam admission of steam turbine, so as to realize the overspeed test of steam-driven pump;Compared with the existing overspeed test mode, cavitation will not occur, and external bearing lubricating water is not required, which ensures the safety and stability of the equipment, reduces the risk of overspeed test, optimizes the overspeed test process and reduces the overspeed test time.

Description

Technical Field

[0001] This invention relates to the field of overspeed testing technology for steam-driven pumps, and in particular to a method for overspeed testing of steam-driven pumps. Background Technology

[0002] The auxiliary feedwater system (ASG) of a nuclear power plant is typically equipped with two steam-driven pumps. Each fuel cycle of these pumps requires mechanical and electromagnetic overspeed protection tests to verify the reliability of the protection measures.

[0003] According to research, the current method for overspeed testing of steam-driven pumps involves gradually closing the pump inlet valve and using external shaft seal water (gradually closing the pump inlet valve increases system flow resistance and reduces flow rate, thus increasing pump speed to achieve overspeed conditions while maintaining a constant steam volume). This method has the following disadvantages: 1. It artificially creates a severe cavitation environment at the pump inlet, exacerbating cavitation damage to the induced draft wheel; 2. Cavitation overspeed conditions accelerate wear on the balance disc; 3. The time required for external shaft seal water connection before and after the test is long, occupying the unit's critical upward path; 4. The risk of overspeed is high; if the pump inlet valve is accidentally fully closed and not opened in time, rotating components will suffer water shortage and damage.

[0004] In view of the above-mentioned shortcomings, it is necessary to design a new method to prevent cavitation during pump overspeed testing, ensure equipment safety, reduce overspeed testing risks, protect personnel and equipment safety, reduce overspeed testing time, and save on the unit's critical path. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an improved method for testing the overspeed of a pneumatic pump.

[0006] The technical solution adopted by this invention to solve its technical problem is: to provide a method for overspeed testing of a pneumatic pump, comprising the following steps:

[0007] S1. Start the steam pump and adjust the flow rate to the first preset value;

[0008] S2. Pull down the connecting rod of the steam inlet regulating valve by lever to increase the opening of the steam inlet regulating valve and perform a mechanical overspeed test on the steam-driven pump;

[0009] S3. Start the steam pump and adjust the flow rate to the second preset value;

[0010] S4. Pull down the connecting rod of the steam inlet regulating valve by lever to increase the opening of the steam inlet regulating valve and perform the electromagnetic overspeed test of the steam pump.

[0011] Preferably, the ultrasonic test method for the steam-driven pump is performed under hot shutdown conditions.

[0012] Preferably, in step S1, the first preset value is 101.9m. 3 / h~110.7m3 / h;

[0013] In step S3, the second preset value is 101.9m 3 / h~110.7m 3 / h.

[0014] Preferably, before step S1, the method further includes: connecting the first end of the lifting rod to the end of the control link between the speed regulator of the steam pump and the steam inlet regulating valve, and placing the opposite second end of the lifting rod away from the control link on the lifting mechanism;

[0015] In step S2, the lifting mechanism raises the second end of the lifting rod upwards, and uses the lever principle to pull down the connecting rod of the steam inlet regulating valve through the first end of the lifting rod and the control linkage, thereby increasing the opening of the regulating valve and increasing the steam inlet of the steam turbine.

[0016] In step S4, the lifting mechanism raises the second end of the lifting rod upwards, and using the lever principle, pulls down the connecting rod of the steam inlet regulating valve through the first end of the lifting rod and the control linkage, thereby increasing the opening of the regulating valve and increasing the steam inlet volume of the steam turbine.

[0017] Preferably, the first end of the lifting rod is provided with a retaining sleeve, which is used to fix the end of the control linkage.

[0018] Preferably, the lifting mechanism includes a base, a lifting device disposed on the base, and a quick-closing unit disposed on the lifting device; the second end of the lifting rod is placed on the quick-closing unit.

[0019] Preferably, the quick-operation unit includes a support base, a bearing base, and a linkage handle;

[0020] The support base is disposed on the top of the lifting device; the bearing seat is movably disposed within the support base, and at least one end of the bearing seat extends out of the support base to support the second end of the lifting rod;

[0021] The linkage handle is connected to the support base via a rotating shaft, with one end of the linkage handle located inside the support base and connected to the bearing seat, while the other end is located outside the support base.

[0022] Preferably, in step S1, after the pneumatic pump is started, it is first run at a preset low flow rate for a predetermined time, and then the flow rate is adjusted to the first preset value; and / or,

[0023] In step S3, after the steam pump is started, the steam pump is first run at a preset low flow rate for a predetermined time, and then the flow rate is adjusted to the second preset value.

[0024] Preferably, before step S1, the trip setting value of the pneumatic pump is set to 9950 rpm;

[0025] After step S2 and before step S3, the trip setting value of the pneumatic pump is set to 9250rpm~9420rpm.

[0026] Preferably, the method further includes the following steps before step S1:

[0027] S0. Start the steam pump at the preset low flow rate. After no abnormalities are found, adjust the flow rate to 126 m3 / h. After collecting the full flow rate data, manually trip the pump.

[0028] The beneficial effects of this invention are as follows: By utilizing the lever principle, the opening of the steam inlet regulating valve is increased by lever method, thereby increasing the steam inlet of the steam turbine and thus realizing the overspeed test of the steam-driven pump; compared with the existing overspeed test method, cavitation will not occur, and no external bearing lubricating water is required, which ensures the safety and stability of the equipment, reduces the risk of overspeed test, optimizes the overspeed test process, and reduces the overspeed test time. Attached Figure Description

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0030] Figure 1 This is a schematic diagram showing the connection between the steam inlet regulating valve and the speed governor in the steam-driven pump overspeed test method of the present invention;

[0031] Figure 2 This is a schematic diagram of the overspeed test device in the pneumatic pump overspeed test method of the present invention;

[0032] Figure 3 This is an exploded structural diagram of the lifting mechanism in the overspeed test device of the pneumatic pump overspeed test method of the present invention. Detailed Implementation

[0033] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0034] The steam-driven pump overspeed test method of the present invention utilizes the lever principle to increase the steam intake of the steam turbine in a lever manner, thereby realizing the overspeed test of the steam-driven pump.

[0035] refer to Figure 1 Combining the steam turbine pump overspeed test, which includes three parts: manual tripping, mechanical overspeed, and electromagnetic overspeed, an embodiment of the steam turbine pump overspeed test method of the present invention may include the following steps:

[0036] S0. Under hot shutdown conditions, start the steam-driven pump at a preset low flow rate. After confirming there are no abnormalities, adjust the flow rate to 126 m³ / h. 3 After collecting full flow data, the system will manually trip the gate at / h.

[0037] Among them, the permissible flow range of the combined steam turbine pump is usually 25m³ / h. 3 / h~185m 3 / h, the preset value for low flow rate is set to 25m³ / h. 3 / h. After confirming no abnormalities were found during on-site inspection, the flow rate was adjusted to 126m³ / h. 3 / h, after collecting full flow data on site, manually trip the turbine pump overspeed test.

[0038] After manually tripping the brake (manually releasing the brake lever), the angle valve on the steam-driven pump opens, the main steam valve closes, and the pump stops. This manual tripping process verifies the usability of the manual tripping mechanism on the steam-driven pump.

[0039] S1. Start the steam pump and adjust the flow rate to the first preset value.

[0040] The first preset value can be 101.9m 3 / h~110.7m 3 / h.

[0041] In addition, in step S1, after the steam-driven pump is started, it is first run at a preset low flow rate for a predetermined time, and then the flow rate is adjusted to the first preset value. The preset low flow rate can be 25m³ / h. 3 / h, the scheduled time can be, but is not limited to, 10 minutes.

[0042] S2. Pull down the connecting rod 101 of the steam inlet regulating valve 100 by lever to increase the opening of the steam inlet regulating valve 100 and perform a mechanical overspeed test of the steam pump.

[0043] In step S2 above, after the opening of the steam inlet regulating valve 100 is increased, the steam inlet of the steam turbine is increased. Under the condition that the opening of the pump outlet valve remains unchanged (under the condition that the load remains unchanged), the pump speed continues to increase.

[0044] In the mechanical overspeed test of the steam-driven pump, when the pump speed is equal to or higher than the set value of the flyweight protection, the flyweight strikes the pressure plate, the angle valve opens, the main steam valve closes, and the pump stops. This mechanical overspeed test of the steam-driven pump can verify the availability of the mechanical trip device within the trip setting range (100 rpm higher than the electromagnetic trip value, ≤9850 rpm).

[0045] Furthermore, considering that the trip setting value in the mechanical overspeed test is ≤9850rpm, before step S1, the trip setting value (protection setting value) of the pneumatic pump is set to 9950rpm. After step S2 and before the subsequent step S3, the trip setting value of the pneumatic pump is set to 9250rpm-9420rpm.

[0046] S3. Start the steam pump and adjust the flow rate to the second preset value.

[0047] The second preset value is 101.9m 3 / h~110.7m 3 / h.

[0048] In step S3, after the steam-driven pump is started, it is first run at a preset low flow rate for a predetermined time, and then the flow rate is adjusted to a second preset value. The preset low flow rate can be 25 m³ / s. 3 / h, the scheduled time can be, but is not limited to, 10 minutes.

[0049] S4. Pull down the connecting rod 101 of the steam inlet regulating valve 100 by lever to increase the opening of the steam inlet regulating valve 100 and perform the electromagnetic overspeed test of the steam pump.

[0050] In step S4 above, after the opening of the steam inlet regulating valve 100 is increased, the steam inlet of the steam turbine is increased. Under the condition that the opening of the pump outlet valve remains unchanged (under the condition that the load remains unchanged), the pump speed continues to increase.

[0051] In the electromagnetic overspeed test of the steam-driven pump, when the pump speed is equal to or greater than the electromagnetic protection setting value, the solenoid valve opens, the main steam valve closes, and the pump stops. This electromagnetic overspeed test of the steam-driven pump can verify the availability of the electromagnetic tripping device within the tripping setting range (9250rpm~9420rpm).

[0052] Furthermore, to achieve the lever method in steps S2 and S4 above, this invention uses an overspeed testing device formed by the lifting rod assembly 10 and the lifting mechanism 20 as a corresponding special tool. (Reference) Figure 2 The lifting rod assembly 10 includes a lifting rod 11 and a retainer 12. The lifting rod 11 has a first end and a second end, and the retainer 12 is disposed on the first end of the lifting rod 11. The second end of the lifting rod 11 is supported on the lifting mechanism 20. When the lifting mechanism 20 performs an upward movement, it can drive the second end of the lifting rod 11 to rise as well.

[0053] refer to Figure 1-2 In conjunction with the above-mentioned overspeed testing device, in the pneumatic pump overspeed testing method of the present invention, the overspeed testing device is installed before the test is conducted, that is:

[0054] Before step S1, the procedure further includes: connecting the first end of the lifting rod 11 to the end of the control link 300 between the speed regulator 200 of the steam pump and the steam inlet regulating valve 100; the first end is provided with a retaining sleeve 12, which is used to fix the lifting rod 11 to the end of the control link 300, so that the lifting rod 11 and the control link 300 are connected axially, increasing the length of the control link 300. The opposite second end of the lifting rod 11 is away from the control link and placed on the lifting mechanism 20.

[0055] In steps S2 and S4, the lifting mechanism 20 moves to raise the second end of the lifting rod 11 (e.g., Figure 1 (The direction of movement is indicated by the arrow on the right). Using the lever principle, the connecting rod 101 of the steam inlet regulating valve 100 is pulled down via the first end of the lifting rod 11 and the control linkage 300 (as shown by the arrow on the right). Figure 1 (As indicated by the arrow on the left), increase the opening of the steam inlet regulating valve 100, thereby increasing the steam inlet volume of the steam turbine.

[0056] Furthermore, corresponding to the end structure of the control link 300, the insert sleeve 12 may further include a cylinder 121 with one end open; at least one wall of the cylinder 121 is provided with a U-shaped groove 122, so that the wall forms an insert portion, which can correspond to the outer peripheral structure of the end of the control link 300.

[0057] The lifting rod 11 is parallel to the axis of the cylinder 121 and its first end is connected to the closed end of the cylinder 121. As one connection method between the lifting rod 11 and the cylinder 121, the first end of the lifting rod 11 can be fixedly connected to the closed end of the cylinder 121 by welding or other means, forming an integral structure. As another connection method between the lifting rod 11 and the cylinder 121, it can be achieved through a threaded connection. That is, the closed end of the cylinder 121 has a threaded hole, and the first end of the lifting rod 11 has an external thread. The first end of the lifting rod 11 is detachably connected to the closed end of the cylinder 121 through this threaded connection. This detachable connection method between the lifting rod 11 and the cylinder 121 facilitates their disassembly, assembly, and storage. It also facilitates the replacement of lifting rods 11 of different lengths or the replacement of the cylinder 121, etc.

[0058] Combination Figure 2 , 3 The lifting mechanism 20 may include a base (not shown), a lifting device 21 mounted on the base, and a quick-closing unit mounted on the lifting device 21. The base serves as the bottom support structure for the entire lifting mechanism 20, contributing to its stable placement. The lifting device 21 drives the second end of its lifting rod 11 to rise and fall through a lifting motion. To match the initial height of the lifting rod assembly 10 after connecting to the control linkage 300 on the pneumatic pump, a bracket may be further provided on the base, allowing adjustment of the height of the lifting device 21 on the base.

[0059] The lifting device 21 can further be a jack or a cylinder. A jack is preferred for the lifting device 21, facilitating slow and stable lifting to stably open the steam inlet regulating valve 100 degrees, thereby improving the stability of the pump's lifting speed. The jack can be a scissor jack, with one end connected to a handwheel for manual operation of opening or closing.

[0060] The quick-action tripping unit allows the second end of the lifting rod 11 to detach from the lifting mechanism 20 by striking it, meaning it is no longer supported on the lifting mechanism 20. The quick-action tripping unit may include a support base 22, a bearing base 23, and a linkage handle 24. The support base 22 is located on top of the lifting device 21; the bearing base 23 is movably disposed within the support base 22, with at least one end extending beyond the support base 22 to support the second end of the lifting rod 11. The linkage handle 24 is connected to the support base 22 via a pivot 241, with one end of the linkage handle 24 located within the support base 22 and connected to the bearing base 23, while the other end is located outside the support base 22. The linkage handle 24 is rotatable relative to the support base 22 via the pivot 241, thereby causing the bearing base 23 connected to it to rotate, disengaging the second end of the lifting rod 11 supported on it.

[0061] Specifically, the support base 22 can be a multi-faceted structure, such as a rectangle. The support base 22 has a receiving groove 221 that penetrates three adjacent sides of the support base 22, forming a U-shaped structure. At the top of the lifting device 21, the support base 22 is placed horizontally, such that the three sides through which its receiving groove 221 penetrates are sequentially adjacent in the horizontal direction.

[0062] The support base 23 is horizontally placed within the receiving groove 221, with its two opposite ends protruding from two opposite sides of the support base 22 (two of the three sides through which the receiving groove 221 passes). The top surfaces of these two protruding ends can be used to position the second end of the lifting rod 11. The linkage handle 24 corresponds to the other side of the support base 22 (the middle one of the three sides through which the receiving groove 221 passes), with one end inserted into the receiving groove 221 and connected to the support base 23, and the other end located outside the support base 22, forming an operating part for operating the linkage handle 24 to rotate.

[0063] To allow for a movable positioning between the linkage handle 24 and the support base 22, a protruding cylinder 242 may be provided on the linkage handle 24 (e.g., at the middle position), and a groove (not shown) may be provided in the support base 22 for positioning the cylinder 242. The cylinder 242 has a central hole for the rotating shaft 241 to pass through.

[0064] The connection between the linkage handle 24 and the support base 23 is not a rigid connection, but rather allows for some movement. (Reference) Figure 3The support seat 23 is provided with a positioning groove 231, the opening of which faces outward from the support seat 22. The support seat 23 is provided with a vertical, oblong hole 232 that communicates with the positioning groove 231. One end of the linkage handle 24 is inserted into the positioning groove 231 and connected to the oblong hole 232 and the end of the linkage handle 24 by a first pin 233, thereby connecting the linkage handle 24 to the support seat 23.

[0065] The linkage handle 24 can rotate horizontally relative to the support base 22, and at the same time, it can drive the bearing base 23 to swing horizontally as well. Furthermore, the end of the linkage handle 24 that enters the positioning groove 231 is arc-shaped to reduce the friction between the end and the inner surface of the positioning groove 231 and ensure smooth rotation of the linkage handle 24.

[0066] In summary, the steam-driven pump overspeed test method of the present invention, through the lever method, transforms the existing method of load reduction into a power increase method (increasing the steam flow rate to increase the pump speed). The pump will not experience cavitation and does not require external bearing lubrication water, ensuring equipment safety and stability, reducing overspeed test risks, optimizing the overspeed test process, reducing overspeed test time, and saving 4 hours of critical path during unit overhaul for each refueling cycle. This has a direct impact on improving the power generation efficiency and nuclear safety level of nuclear power plants.

[0067] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for overspeed testing of a pneumatic pump, characterized in that, The method comprises the following steps: S1, starting the steam-driven pump and adjusting the flow to a first preset value; Before step S1, further comprising: connecting the first end of the lifting rod to the end of the control connecting rod of the speed regulator and the steam admission adjusting valve of the steam-driven pump, the second end of the lifting rod being away from the control connecting rod and placed on the lifting mechanism; S2, lowering the connecting rod of the steam admission adjusting valve by the lever method to increase the opening of the steam admission adjusting valve, and performing the mechanical overspeed test of the steam-driven pump; S3, starting the steam-driven pump and adjusting the flow to a second preset value; S4, lowering the connecting rod of the steam admission adjusting valve by the lever method to increase the opening of the steam admission adjusting valve, and performing the electromagnetic overspeed test of the steam-driven pump; The lifting mechanism comprises a base, a lifting device arranged on the base, and a quick braking unit arranged on the lifting device; the second end of the lifting rod is placed on the quick braking unit; The quick braking unit comprises a support seat, a bearing seat, and a linkage handle; the support seat is arranged on the top of the lifting device; the bearing seat is movably arranged in the support seat, and at least one end of the bearing seat extends out of the support seat to support the second end of the lifting rod; The linkage handle is connected to the support seat through a rotating shaft, and one end of the linkage handle is located in the support seat and connected to the bearing seat, and the other end is located outside the support seat.

2. The turbine pump overspeed test method of claim 1, wherein, The steam-driven pump overspeed test method is performed under the condition of hot shutdown.

3. The turbine pump overspeed test method of claim 1, wherein, In step S1, the first preset value is 101.9 m 3 / h ~ 110.7 m 3 / h; In step S3, the second preset value is 101.9 m 3 / h ~ 110.7 m 3 / h.

4. The turbine pump overspeed test method of claim 1, wherein, In step S2, the lifting mechanism acts to lift the second end of the lifting rod upward, and the connecting rod of the steam admission adjusting valve is lowered by the first end of the lifting rod and the control connecting rod through the lever principle to increase the opening of the adjusting valve, thereby increasing the steam admission of the steam turbine; under the condition that the opening of the pump outlet valve remains unchanged, the pump speed continues to rise; In step S4, the lifting mechanism acts to lift the second end of the lifting rod upward, and the connecting rod of the steam admission adjusting valve is lowered by the first end of the lifting rod and the control connecting rod through the lever principle to increase the opening of the adjusting valve, thereby increasing the steam admission of the steam turbine; under the condition that the opening of the pump outlet valve remains unchanged, the pump speed continues to rise.

5. The turbine pump overspeed test method as defined in claim 1, wherein, A card insertion sleeve is arranged on the first end of the lifting rod and fixed on the end of the control connecting rod.

6. The turbine pump overspeed test method as defined in claim 1, wherein, In step S1, after the steam-driven pump is started, the steam-driven pump is operated at a preset small flow value for a predetermined time, and then the flow is adjusted to the first preset value; and / or, In step S3, after the steam-driven pump is started, the steam-driven pump is operated at a preset small flow value for a predetermined time, and then the flow is adjusted to the second preset value.

7. The turbine pump overspeed test method as defined in claim 1, wherein Before step S1, the trip setting value of the steam-driven pump is set to 9950 rpm; After step S2 and before step S3, the trip setting value of the steam-driven pump is set to 9250 rpm to 9420 rpm.

8. The turbo-pump overspeed test method of any of claims 1-7, wherein, Before step S1, further comprising: S0, start the steam-driven pump at a small flow rate preset value, and adjust the flow rate to 126 m 3 / h after collecting full flow data, execute manual tripping.

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