Main steam to shaft seal system of steam turbine
By introducing interconnected pipelines and multi-level control units into the turbine main steam to shaft seal system, the problem of insufficient auxiliary steam temperature during turbine hot start-up was solved, the matching of shaft seal steam supply temperature and cylinder temperature was achieved, enabling rapid start-up and reducing costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- INNER MONGOLIA JINGTAI POWER GENERATION
- Filing Date
- 2025-08-15
- Publication Date
- 2026-05-19
AI Technical Summary
The existing self-sealing steam seal system suffers from insufficient auxiliary steam supply to the shaft seal temperature during hot start-up 24-72 hours after turbine shutdown. This leads to localized cooling inside the turbine, large rotor shrinkage, large negative expansion difference between high and medium pressure, difficulty in unit startup, and insufficient temperature of auxiliary steam supplied alone.
Design a steam turbine main steam to shaft seal system, including a first steam supply system, a second steam supply system and interconnecting pipelines. The interconnecting pipelines achieve temperature matching between the steam supply systems under thermal conditions, ensuring that the shaft seal steam supply temperature matches the cylinder temperature and avoiding localized cooling. A multi-stage control unit and condensate drain design are adopted to achieve mutual backup of the main steam supply to the shaft seal.
It enables rapid start-up of steam turbines, avoids internal cooling problems, eliminates rotor shrinkage and negative expansion difference, reduces start-up time and cost, and reduces equipment maintenance and power consumption.
Smart Images
Figure CN224260404U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of steam engine technology, and specifically to a steam turbine main steam to shaft seal system. Background Technology
[0002] Steam turbines on the market typically employ a self-sealing steam sealing system. This means that during normal operation of the unit, the steam leaking from the high- and intermediate-pressure cylinder shaft end steam seals is cooled by water spray and then used as steam to supply the low-pressure shaft end steam seal. Excess steam leaks through the overflow station to the low-pressure heater or exhaust device. During unit startup or low-load operation, the steam supply to the steam seal is provided by external steam. This steam sealing system can automatically switch according to the unit's steam seal supply requirements throughout the entire process from unit startup to full-load operation.
[0003] Self-sealing steam sealing systems are typically designed with two steam sources: auxiliary steam and main steam. The main steam serves as an emergency backup steam source. During normal operation, the manual isolation valve to the shaft seal header is open, while the electric valve and regulating valve are closed. In the event of a unit trip due to a fault, the main steam can be used to supply the shaft seal steam source during unit shutdown coasting and restart.
[0004] The existing self-sealing steam seal system has the following problems: When the steam turbine is started in a hot state after a 24-72 hour shutdown, the auxiliary steam supply to the shaft seal is insufficient due to the boiler depressurization, resulting in localized cooling inside the turbine, large rotor shrinkage in the shaft seal area, and a large negative expansion difference between the high and intermediate pressures, making it difficult to start the unit. After a normal shutdown and vacuum breaking, friction noise is emitted at the front and rear ends of the high (intermediate) pressure cylinder steam seals during turning gear operation. The noise disappears when the shaft seal supply is not temporarily depressurized, but the main steam supply to the shaft seal can only be maintained for a maximum of less than 24 hours, and the temperature of the auxiliary steam supply alone is insufficient. This utility model proposes a new solution to the above problems. Utility Model Content
[0005] To overcome at least one of the aforementioned drawbacks, this invention provides a steam turbine main steam to shaft seal system. The objective of this invention can be achieved by adopting the following technical solution:
[0006] This application provides a steam turbine main steam to shaft seal system, including:
[0007] The first steam supply system includes a first main steam supply pipeline, which is connected to a first shaft seal steam supply header.
[0008] The second steam supply system includes a second main steam supply pipeline, and the first main steam supply pipeline is connected to the second shaft seal steam supply header.
[0009] An interconnected pipeline, wherein the first end of the interconnected pipeline is connected to the first main steam supply pipeline, and the second end is connected to the second main steam supply pipeline.
[0010] In one possible implementation, when the first steam supply system is in operation and the second steam supply system is shut down and needs to be started, the first main steam supply pipeline supplies steam to the second main steam supply pipeline through the interconnecting pipeline until the shaft seal steam supply temperature matches the cylinder temperature when the second main steam supply pipeline is started in hot condition.
[0011] In one possible implementation, the interconnected pipeline is equipped with an interconnected electric shut-off valve, which divides the interconnected pipeline into a first connecting pipe section and a second connecting pipe section. The first connecting pipe section is used to connect to the first main steam supply pipeline, and the second connecting pipe section is used to connect to the second main steam supply pipeline.
[0012] In one possible implementation, a first drainage point is connected to the first connecting pipe section, and a first drainage hole is provided on the first drainage point, wherein the diameter of the first drainage hole is 8mm-15mm.
[0013] The second connecting pipe section is connected to a second drainage point, and the second drainage point is provided with a second drainage hole, the diameter of which is 8mm-15mm.
[0014] In one possible implementation, the first main steam supply pipeline is equipped with:
[0015] The first manual shut-off valve is located on the side closest to the main steam source;
[0016] The first electric shut-off valve is located on the side of the first manual shut-off valve that is away from the main steam source.
[0017] The connection point between the first end of the interconnected pipeline and the first main steam supply pipeline is located between the first manual shut-off valve and the first electric shut-off valve.
[0018] In one possible implementation, a first regulating valve is provided on the first main steam supply pipeline for regulating the pressure of the first main steam supply pipeline, the first regulating valve comprising:
[0019] The first filter pressure reducing valve is used to filter compressed air and remove impurities.
[0020] The first electro-pneumatic positioner has its output end connected to the input end of the first filter pressure reducing valve to provide working power to the first electro-pneumatic positioner. The first electro-pneumatic positioner is used to convert the electrical signal output by the control system into a pneumatic pressure signal and output driving pneumatic pressure to the first actuator to push the first valve stem to move.
[0021] A first valve position transmission, connected to the first valve stem, is used to convert the mechanical displacement of the first valve stem into an electrical signal and feed it back to the control system.
[0022] In one possible implementation, a first auxiliary pipe is connected to the first main steam supply pipe, the first auxiliary pipe is connected to the first shaft seal steam supply header, and the first auxiliary pipe is provided with a first throttling orifice with a diameter of 2mm-5mm.
[0023] In one possible implementation, the second main steam supply pipeline is equipped with:
[0024] The second manual shut-off valve is located on the side closest to the main steam source;
[0025] The second electric shut-off valve is located on the side of the second manual shut-off valve that is away from the main steam source.
[0026] The connection point between the second end of the interconnected pipeline and the second main steam supply pipeline is located between the second manual shut-off valve and the second electric shut-off valve.
[0027] In one possible implementation, a second regulating valve is provided on the second main steam supply pipeline for regulating the pressure of the second main steam supply pipeline, the second regulating valve comprising:
[0028] The second filter pressure reducing valve is used to filter compressed air and remove impurities.
[0029] The second electro-pneumatic positioner is connected to the input of the second electro-pneumatic positioner at the output end of the second filter pressure reducing valve to provide working power for the second electro-pneumatic positioner. The second electro-pneumatic positioner is used to convert the electrical signal output by the control system into a pneumatic signal and output driving pneumatic pressure to the second actuator to push the second valve stem to move.
[0030] The second valve position transmission is connected to the second valve stem and is used to convert the mechanical displacement of the second valve stem into an electrical signal that is fed back to the control system.
[0031] In one possible implementation, a second auxiliary pipe is connected to the second main steam supply pipe, the second auxiliary pipe is connected to the second shaft seal steam supply header, and the second auxiliary pipe is provided with a second throttling orifice, the diameter of which is 2mm-5mm.
[0032] The beneficial technical effects of this utility model are as follows: According to the present disclosure, the turbine main steam to shaft seal system includes a first steam supply system, a second steam supply system, and interconnecting pipelines. One operating steam supply system is connected to another shut-down steam supply system that needs to be started through the interconnecting pipelines, ensuring that the shaft seal steam supply temperature matches the cylinder temperature when the steam supply system is started in a hot state. This avoids local cooling inside the turbine, eliminates rotor shrinkage and negative expansion difference problems, and enables the main steam supply to the shaft seal of the two units to serve as backups for each other. It solves the problem of insufficient temperature when supplying auxiliary steam alone, greatly shortens the start-up time, eliminates the need to add electric heaters, reduces electricity consumption and saves costs, and reduces equipment maintenance and labor costs. Attached Figure Description
[0033] The following are given by way of example and without limitation in the accompanying drawings:
[0034] Figure 1 A schematic diagram of the main steam to shaft seal system of the steam turbine according to an embodiment of the present invention is shown;
[0035] Figure 2 A schematic diagram showing the structural details of the turbine main steam to shaft seal system according to an embodiment of the present invention is provided.
[0036] In the picture:
[0037] 1. First steam supply system; 11. First manual shut-off valve; 12. First electric shut-off valve; 13. First regulating valve; 131. First filter pressure reducing valve; 132. First electro-pneumatic positioner; 133. First valve position gearbox; 14. First throttle orifice; 2. Second steam supply system; 21. Second manual shut-off valve; 22. Second electric shut-off valve; 23. Second regulating valve; 231. Second filter pressure reducing valve; 232. Second electro-pneumatic positioner; 233. Second valve position gearbox; 24. Second throttle orifice; 31. First steam supply header to shaft seal; 32. Second steam supply header to shaft seal; 4. Interconnecting pipeline; 41. Interconnecting electric shut-off valve; 42. First drain point; 43. Second drain point. Detailed Implementation
[0038] In the following detailed disclosure, these embodiments are fully described with reference to the accompanying drawings. In order to enable those skilled in the art to understand and clarify the technical solution of this utility model more clearly, the embodiments described below are not limited thereto. The present utility model will be further described in detail below with reference to the embodiments and the accompanying drawings.
[0039] In this utility model, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; the term "multiple" refers to two or more unless otherwise explicitly defined. The terms "install," "connect," "join," and "fix" should be interpreted broadly. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; "join" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0040] In the description of this utility model, it should be understood that the terms "upper", "lower", "left", "right", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or unit referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0041] This application provides a steam turbine main steam to shaft seal system, such as Figure 1 and Figure 2 As shown, the system includes a first steam supply system 1, a second steam supply system 2, and an interconnecting pipeline 4. The first steam supply system 1 includes a first main steam supply pipeline, which is connected to a first shaft seal steam supply header 31. The second steam supply system 2 includes a second main steam supply pipeline, which is connected to a second shaft seal steam supply header 32. The first end of the interconnecting pipeline 4 is connected to the first main steam supply pipeline, and the second end is connected to the second main steam supply pipeline.
[0042] The turbine main steam to shaft seal system provided in this embodiment includes a first steam supply system 1, a second steam supply system 2, and an interconnecting pipeline 4. One operating steam supply system is connected to another shut-down steam supply system that needs to be started through the interconnecting pipeline 4. This ensures that the shaft seal steam supply temperature matches the cylinder temperature when the steam supply system is started in a hot state, avoiding local cooling inside the turbine. This eliminates rotor shrinkage and negative expansion difference problems, and enables the main steam supply to the shaft seal of the two units to serve as backups for each other. It solves the problem of insufficient temperature when supplying auxiliary steam alone, greatly shortens the start-up time, eliminates the need to add electric heaters, significantly reduces start-up energy consumption, and reduces equipment maintenance and labor costs. At the same time, the modification of the existing system is simple, saves on-site installation space, is easy to operate, and has low modification costs.
[0043] In one possible implementation, when the first steam supply system 1 is in operation and the second steam supply system 2 is shut down and needs to be started, the first main steam supply pipeline supplies steam to the second main steam supply pipeline through the interconnecting pipeline 4 until the second main steam supply pipeline reaches the hot start-up temperature, at which point the second main steam supply pipeline enters the steam supply operation state.
[0044] The turbine main steam to shaft seal system provided in this embodiment adopts a parallel design of the first steam supply system 1 and the second steam supply system 2, and realizes bidirectional steam connection through the interconnection pipeline 4. When one unit is shut down, the main steam of the running unit can supply steam to the unit to be started through the interconnection pipeline 4, so that the shaft seal temperature matches the cylinder temperature (420℃-520℃), avoiding the local cooling problem caused by traditional auxiliary steam supply (≤350℃).
[0045] In one possible implementation, such as Figure 2 As shown, the interconnected pipeline 4 is equipped with an interconnected electric shut-off valve 41, which divides the interconnected pipeline 4 into a first connecting pipe section and a second connecting pipe section. The first connecting pipe section is used to connect to the first main steam supply pipeline, and the second connecting pipe section is used to connect to the second main steam supply pipeline.
[0046] The interconnected pipeline 4 is divided into two independent connecting pipe sections by the interconnected electric shut-off valve 41, thereby achieving physical isolation between the first main steam pipeline and the second main steam pipeline.
[0047] In one possible implementation, such as Figure 2 As shown, a first drainage point 42 is connected to the first connecting pipe section, and a first drainage hole is provided on the first drainage point 42. The diameter of the first drainage hole is 8mm-15mm. A second drainage point 43 is connected to the second connecting pipe section, and a second drainage hole is provided on the second drainage point 43. The diameter of the second drainage hole is 8mm-15mm.
[0048] The first condensate drain 42 independently covers the corresponding first connecting pipe section, and the second condensate drain 43 independently covers the corresponding second connecting pipe section. The dual condensate drain arrangement can specifically handle the condensate accumulation in different pipe sections. In the event of a single point failure, the backup condensate drain can still maintain basic drainage function, eliminating the condensate blind zone problem that is easy to occur in traditional single-point condensate drains. The 8mm-15mm orifice diameter design balances drainage efficiency and steam barrier requirements, avoiding the problem of small holes being easy to clog or large holes being prone to steam leakage.
[0049] In one possible implementation, such as Figure 2As shown, the first main steam supply pipeline is equipped with a first manual shut-off valve 11 and a first electric shut-off valve 12. The first manual shut-off valve 11 is located on the side close to the main steam source, and the first electric shut-off valve 12 is located on the side away from the main steam source. The connection between the first end of the interconnecting pipeline 4 and the first main steam supply pipeline is located between the first manual shut-off valve and the first electric shut-off valve 12.
[0050] The first main steam supply pipeline is connected in series with a first manual shut-off valve 11 and a first electric shut-off valve 12 to form a multi-level control unit. The first manual shut-off valve 11 serves as the first barrier of the first steam supply system 1, providing physical isolation and ensuring complete gas supply cut-off during maintenance. The first electric shut-off valve 12 supports remote rapid operation and linkage with the automation system. The manual valve serves as the final safety guarantee, allowing manual shut-off of the gas supply in case of electric valve failure. The rapid response characteristics of the electric valve effectively prevent the risk of pressure surge. The physical isolation of the dual valve group eliminates the hidden danger of single-point failure. The pipe section between the first manual shut-off valve 11 and the first electric shut-off valve 12 serves as a node connecting to the first connecting pipeline, retaining safe docking space. The interconnection interface is always in a controllable pressure environment to ensure operational safety.
[0051] In one possible implementation, such as Figure 2 As shown, a first regulating valve 13 is provided on the first main steam supply pipeline for regulating the pressure of the first main steam supply pipeline. The first regulating valve 13 includes a first filter pressure reducing valve 131, a first electro-pneumatic positioner 132, and a first valve position gearbox 133. The first filter pressure reducing valve 131 is used to filter compressed air to remove impurities. The output end of the first filter pressure reducing valve 131 is connected to the input end of the first electro-pneumatic positioner 132 to provide working power for the first electro-pneumatic positioner 132. The first electro-pneumatic positioner 132 is used to convert the electrical signal output by the control system into a pneumatic pressure signal and output driving pneumatic pressure to the first actuator to push the first valve stem to move. The first valve position gearbox 133 is connected to the first valve stem and is used to convert the mechanical displacement of the first valve stem into an electrical signal and feed it back to the control system.
[0052] The first main steam supply pipeline is connected in series with a first manual shut-off valve 11, a first electric shut-off valve 12 and a first regulating valve 13 to form a three-level control unit.
[0053] Among them, the first filter pressure reducing valve 131 of the first regulating valve 13 ensures the cleanliness and pressure stability of the air source, eliminates the risk of wear on precision components caused by impurities, extends the service life of the equipment, and enables the first electro-pneumatic positioner 132 to obtain constant power input. The first electro-pneumatic positioner 132 drives the actuator to adjust the valve opening through real-time conversion of electrical signal to air pressure signal. The first valve position gearbox 133 forms a displacement-electrical signal closed-loop feedback, dynamically corrects control deviations, and ensures steady-state control accuracy.
[0054] In one possible implementation, such as Figure 2 As shown, a first auxiliary pipe is connected to the first main steam supply pipe. The first auxiliary pipe is connected to the first shaft seal steam supply header 31. The first auxiliary pipe is provided with a first throttling orifice 14, and the diameter of the first throttling orifice 14 is 2mm-5mm.
[0055] The diameter of the first throttling orifice 14 restricts the regulating steam flow rate, prevents excessive steam from entering the first shaft seal steam supply header 31, ensures that the steam supply matches the demand, avoids system overload or fluctuations, maintains the pressure in the shaft seal steam supply chamber within a stable range by constraining steam flow, reduces the impact of pressure fluctuations on sealing performance, prevents steam leakage or air infiltration, limits the delivery of excess steam, optimizes the heat recovery process, reduces ineffective losses, supports energy-saving operation of the system, and reduces operating costs.
[0056] In one possible implementation, such as Figure 2 As shown, the second main steam supply pipeline is equipped with a second manual shut-off valve 21 and a second electric shut-off valve 22. The second manual shut-off valve 21 is located on the side close to the main steam source, and the second electric shut-off valve 22 is located on the side away from the main steam source. The connection between the second end of the interconnecting pipeline 4 and the second main steam supply pipeline is located between the second manual shut-off valve and the second electric shut-off valve 22.
[0057] The second main steam supply pipeline is connected in series with a second manual shut-off valve 21 and a second electric shut-off valve 22 to form a multi-level control unit. The second manual shut-off valve 21 serves as the first barrier of the second steam supply system 2, providing physical isolation and ensuring complete gas supply cut-off during maintenance. The second electric shut-off valve 22 supports remote rapid operation and linkage with the automation system. The manual valve serves as the final safety guarantee, allowing manual shut-off of the gas supply in case of electric valve failure. The rapid response characteristics of the electric valve effectively prevent the risk of pressure surge. The physical isolation of the dual valve group eliminates the hidden danger of single-point failure. The pipe section between the second manual shut-off valve 21 and the second electric shut-off valve 22 serves as the node connecting to the second connecting pipeline, retaining safe docking space. The interconnection interface is always in a controllable pressure environment to ensure operational safety.
[0058] In one possible implementation, such as Figure 2As shown, a second regulating valve 23 is provided on the second main steam supply pipeline for regulating the pressure of the second main steam supply pipeline. The second regulating valve 23 includes a second filter pressure reducing valve 331, a second electro-pneumatic positioner 332, and a second valve position gearbox 333. The second filter pressure reducing valve 331 is used to filter compressed air to remove impurities. The output end of the second filter pressure reducing valve 331 is connected to the input end of the second electro-pneumatic positioner 332 to provide working power for the second electro-pneumatic positioner 332. The second electro-pneumatic positioner 332 is used to convert the electrical signal output by the control system into a pneumatic pressure signal and output driving pneumatic pressure to the second actuator to drive the second valve stem. The second valve position gearbox 333 is connected to the second valve stem and is used to convert the mechanical displacement of the second valve stem into an electrical signal and feed it back to the control system.
[0059] Among them, the second filter pressure reducing valve 331 of the second regulating valve 23 ensures the cleanliness and pressure stability of the air source, eliminates the risk of wear on precision components caused by impurities, extends the service life of the equipment, and enables the second electro-pneumatic positioner 332 to obtain constant power input. The second electro-pneumatic positioner 332 drives the actuator to adjust the valve opening through real-time conversion of electrical signal to pneumatic signal. The second valve position speed reducer 333 forms a displacement-electrical signal closed-loop feedback, dynamically corrects control deviations, and ensures steady-state control accuracy.
[0060] In one possible implementation, such as Figure 2 As shown, a second auxiliary pipe is connected to the second main steam supply pipe. The second auxiliary pipe is connected to the second shaft seal steam supply header 32. The second auxiliary pipe is provided with a second throttling orifice 24, and the diameter of the second throttling orifice 24 is 2mm-5mm.
[0061] The diameter of the second throttling orifice 24 restricts the regulating steam flow rate, preventing excessive steam from entering the second shaft seal steam supply header 32, ensuring that the steam supply matches the demand, avoiding system overload or fluctuations, maintaining the pressure in the shaft seal steam supply chamber within a stable range by constraining steam flow, reducing the impact of pressure fluctuations on sealing performance, preventing steam leakage or air infiltration, limiting the delivery of excess steam, optimizing the heat recovery process, reducing ineffective losses, supporting energy-saving operation of the system and reducing operating costs.
[0062] Understandably, traditional steam turbine main steam to shaft seal system employs a self-sealing steam seal system. During normal unit operation, the leaking steam from the high and intermediate pressure cylinder shaft end seals is de-cooled by water spray and then used as steam to supply the low-pressure shaft end seal. Excess leaking steam overflows through the overflow station to the low-pressure heater or exhaust device. During unit startup or low-load operation, the seal steam supply is provided by external steam. The shaft seal system is designed to use main steam for startup. During hot startup, the steam supply system provides shaft seal steam by opening manual shut-off valves, electric shut-off valves, and regulating valves. However, due to the low and slow rise of the main steam temperature during initial startup, the shaft seal temperature is less than 350°C, causing localized cooling inside the turbine. This results in significant rotor shrinkage in the shaft seal area, a large negative expansion difference between the high and intermediate pressures, and difficulties in starting the unit.
[0063] The turbine main steam to shaft seal system provided in this embodiment is interconnected with the first steam supply system 1 and the second steam supply system 2 by adding an interconnection pipe 4. When the first steam supply system 1 is running and the first steam supply system 2 is shut down and needs to be started, the first manual shut-off valve 11 and the interconnection electric shut-off valve 41 can be opened to check that the first condensate drain point 42 and the second condensate drain point 43 are draining normally. Then, the second electric shut-off valve 22 and the second regulating valve 23 of the second steam supply system 2 can be opened successively to adjust the shaft seal steam supply pressure to about 27 kPa.
[0064] Understandably, when the first steam supply system 1 starts, the startup process for the second steam supply system 2 is similar.
[0065] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0066] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.
[0067] In view of the detailed description above, these and other changes can be made to these embodiments. This written description includes embodiments of the best mode disclosed in this utility model. The patent scope of this utility model is defined by the claims, which are not limited by this disclosure. The protection scope of this utility model is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope disclosed in this utility model, based on the technical solution and concept of this utility model, are within the protection scope of this utility model.
Claims
1. A steam turbine main steam to shaft seal system, characterized in that, include: The first steam supply system (1) includes a first main steam supply pipeline, which is connected to the first shaft seal steam supply header (31). The second steam supply system (2) includes a second main steam supply pipeline, and the first main steam supply pipeline is connected to the second shaft seal steam supply header (32). Interconnected pipe (4), the first end of which is connected to the first main steam supply pipe and the second end of which is connected to the second main steam supply pipe.
2. The turbine main steam to shaft seal system according to claim 1, characterized in that, When the first steam supply system (1) is in operation and the second steam supply system (2) is shut down and needs to be started, the first main steam supply pipeline supplies steam to the second main steam supply pipeline through the interconnecting pipeline (4) until the shaft seal steam supply temperature matches the cylinder temperature when the second main steam supply pipeline is started in hot condition.
3. The turbine main steam to shaft seal system according to claim 2, characterized in that, The interconnected pipeline (4) is equipped with an interconnected electric shut-off valve (41), which divides the interconnected pipeline (4) into a first connecting pipe section and a second connecting pipe section. The first connecting pipe section is used to connect to the first main steam supply pipeline, and the second connecting pipe section is used to connect to the second main steam supply pipeline.
4. The turbine main steam to shaft seal system according to claim 3, characterized in that, The first connecting pipe section is connected to a first drainage point (42), and the first drainage point (42) is provided with a first drainage hole, the diameter of the first drainage hole being 8mm-15mm; The second connecting pipe section is connected to a second drainage point (43), and the second drainage point (43) is provided with a second drainage hole, the diameter of which is 8mm-15mm.
5. The turbine main steam to shaft seal system according to claim 1, characterized in that, The first main steam supply pipeline is equipped with: The first manual shut-off valve (11) is located on the side close to the main steam source; The first electric shut-off valve (12) is located on the side of the first manual shut-off valve (11) away from the main steam source. The connection point between the first end of the interconnecting pipe (4) and the first main steam supply pipe is located between the first manual shut-off valve and the first electric shut-off valve (12).
6. The turbine main steam to shaft seal system according to claim 5, characterized in that, A first regulating valve (13) is provided on the first main steam supply pipeline for regulating the pressure of the first main steam supply pipeline. The first regulating valve (13) includes: The first filter pressure reducing valve (131) is used to filter compressed air to remove impurities. The first electro-pneumatic positioner (132) is connected to the input of the first electro-pneumatic positioner (132) at the output end of the first filter pressure reducing valve (131) for providing working power to the first electro-pneumatic positioner (132). The first electro-pneumatic positioner (132) is used to convert the electrical signal output by the control system into a pneumatic signal and output driving pneumatic pressure to the first actuator to push the first valve stem to move. A first valve position transmission (133) is connected to the first valve stem and is used to convert the mechanical displacement of the first valve stem into an electrical signal and feed it back to the control system.
7. The turbine main steam to shaft seal system according to claim 5, characterized in that, The first main steam supply pipeline is connected to a first auxiliary pipeline, which is connected to the first shaft seal steam supply header (31). The first auxiliary pipeline is provided with a first throttling orifice (14), and the diameter of the first throttling orifice (14) is 2mm-5mm.
8. The turbine main steam to shaft seal system according to claim 1, characterized in that, The second main steam supply pipeline is equipped with: The second manual shut-off valve (21) is located on the side close to the main steam source; The second electric shut-off valve (22) is located on the side of the second manual shut-off valve (21) away from the main steam source; The connection point between the second end of the interconnecting pipe (4) and the second main steam supply pipe is located between the second manual shut-off valve and the second electric shut-off valve (22).
9. The turbine main steam to shaft seal system according to claim 8, characterized in that, A second regulating valve (23) is provided on the second main steam supply pipeline for regulating the pressure of the second main steam supply pipeline. The second regulating valve (23) includes: The second filter pressure reducing valve (231) is used to filter compressed air to remove impurities. The second electro-pneumatic positioner (232) is connected to the input of the second electro-pneumatic positioner (232) at the output end of the second filter pressure reducing valve (231) to provide working power for the second electro-pneumatic positioner (232). The second electro-pneumatic positioner (232) is used to convert the electrical signal output by the control system into a pneumatic signal and output driving pneumatic pressure to the second actuator to push the second valve stem to move. The second valve position transmission (233) is connected to the second valve stem and is used to convert the mechanical displacement of the second valve stem into an electrical signal and feed it back to the control system.
10. The turbine main steam to shaft seal system according to claim 8, characterized in that, The second main steam supply pipeline is connected to a second auxiliary pipeline. The second auxiliary pipeline is connected to the second shaft seal steam supply header (32). The second auxiliary pipeline is provided with a second throttling orifice (24). The diameter of the second throttling orifice (24) is 2mm-5mm.