Frontal steam turbine and steam turbine system suitable for high exhaust pressure

Abstract

The application discloses a front-mounted steam turbine suitable for high exhaust pressure and a steam turbine system. The inner cylinder of the front-mounted steam turbine comprises a first inner cylinder body and a second inner cylinder body formed by a first boundary surface of an axis, the outer cylinder comprises a first outer cylinder body and a second outer cylinder body formed by a second boundary surface perpendicular to the axis, and the cylinder walls of the first inner cylinder body and the second inner cylinder body are fixed by a circular ring on both sides respectively. The inner wall surfaces of the first outer cylinder body and the second outer cylinder body are respectively provided with annular skirt parts and are matched with the outer circumferential surfaces of the circular rings respectively. The two annular skirt parts and the outer wall surface of the inner cylinder and the inner wall surface of the outer cylinder form a low-pressure chamber. The cylinder wall of the outer cylinder is provided with a pressure balance hole penetrating into the low-pressure chamber and used for connecting the low-pressure area. Based on the overall structure optimization, the carrying capacity of the outer cylinder can be effectively improved, and the pressure isolation mechanism is established based on the low-pressure chamber, so that the action range of the high exhaust pressure is greatly reduced, and reliable technical support is provided for improving the exhaust pressure of the unit.

Description

Technical Field

[0001] This invention relates to the field of coal-fired power generation technology, and specifically to a front-mounted steam turbine and turbine system suitable for high exhaust pressure. Background Technology

[0002] The front-mounted steam turbine is usually connected in series with other steam turbines such as the main steam turbine. During operation, the front-mounted steam turbine uses the high-parameter steam to perform energy conversion and work, recovering the initial energy of the high-pressure steam. Then, the exhaust steam, which is still at a high pressure and temperature, is sent to the subsequent steam turbines for them to continue expanding and doing work. Through this series cooperation mode, the overall power generation capacity of the power plant can be effectively improved.

[0003] In front-mounted steam turbines, both the inlet and outlet pressures are relatively high, requiring a compact design to ensure good cylinder sealing and sufficient strength. A typical front-mounted steam turbine consists of an outer cylinder and an inner cylinder to achieve a reasonable distribution of the pressure gradient; however, the higher outlet pressure is primarily borne independently by the outer cylinder.

[0004] To ensure that the outer cylinder of the front-mounted steam turbine can stably withstand high steam pressure, systematic optimization and upgrading can be carried out from two aspects: cylinder structure design and material selection. However, the exhaust pressure of the front-mounted steam turbine needs to be controlled within a safe threshold range, such as but not limited to 10MPa, to ensure safe and stable operation. This cannot meet the needs of the evolution of units with higher exhaust pressure.

[0005] For units with higher exhaust pressure, conventional solutions include increasing cylinder wall thickness, using high-strength materials, and enlarging bolt sizes to enhance cylinder strength and sealing performance. However, these measures increase cylinder thermal stress during turbine start-up and shutdown, and due to limitations in material properties and thermal stress, it remains difficult to effectively increase the unit's exhaust pressure.

[0006] In view of this, it is urgent to optimize the operating structure of front-mounted steam turbines in order to overcome the above-mentioned defects. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a front-mounted steam turbine and turbine system suitable for high exhaust pressure. Through overall structural optimization, the load-bearing capacity of the outer cylinder can be effectively improved, providing a reliable technical guarantee for increasing the exhaust pressure of the unit.

[0008] This invention provides a front-mounted steam turbine suitable for ultra-high exhaust pressure. The front-mounted steam turbine includes a nested outer cylinder and an inner cylinder, both of which are separate structures. The inner cylinder includes a first inner cylinder body and a second inner cylinder body formed by a first interface passing through the axis, and the first inner cylinder body and the second inner cylinder body are fixedly connected by a first connecting bolt embedded in the cylinder body. The outer cylinder includes a first outer cylinder body and a second outer cylinder body formed by a second interface perpendicular to the axis. The facing opening ends of the first outer cylinder body and the second outer cylinder body each have an annular flange, which is connected by a connecting bolt inserted into the two cylinder bodies. The second connecting bolt of the annular flange is used for fixed connection; both sides of the cylinder walls of the first inner cylinder and the second inner cylinder have reduced diameter sections, which are fixed by interference fit rings respectively; the inner walls of the first outer cylinder and the second outer cylinder are respectively provided with annular skirts, both of which extend toward the inner cylinder and are adapted to the outer circumferential surface of the corresponding rings; the two annular skirts, together with the outer wall of the inner cylinder and the inner wall of the outer cylinder, form a low-pressure chamber, and the cylinder wall of the outer cylinder is provided with a pressure balance hole that extends to the low-pressure chamber, which is used to connect the low-pressure area.

[0009] Optionally, the pressure balancing hole is formed in the cylinder wall of the first outer cylinder.

[0010] Optionally, the annular skirt portion and the outer peripheral surface of the corresponding ring are fitted with a zero-clearance sealing ring.

[0011] Optionally, the first inner cylinder and the second inner cylinder form an air intake chamber, and air intake ports communicating with the air intake chamber are respectively provided on the radially opposite sides of the air intake chamber.

[0012] The outer wall surface of the air intake chamber located on one side of the line connecting the centers of the two air intakes, and the outer wall surface of the air intake chamber located on the other side of the line connecting the centers of the two air intakes, both exhibit a gradually decreasing radial dimension from one air intake to the other air intake. Correspondingly, the cylinder wall thickness of the inner cylinder exhibits a gradually increasing trend. The outer wall surface located on one side of the line connecting the centers of the two air intakes is rotationally symmetrical with respect to the rotor center to the outer wall surface located on the other side of the line connecting the centers of the two air intakes.

[0013] The first interface is located in the radially small-sized area of ​​the outer wall on both sides, and the first connecting bolt is embedded in the cylinder wall on both sides, which has a thicker wall thickness, corresponding to the radially small-sized area.

[0014] Optionally, the outer wall surface has a flow-guiding arc surface at one end with a smaller radial dimension and a flow-guiding rounded corner at the other end with a larger radial dimension.

[0015] Optionally, the inner cylinder includes a supporting and positioning protrusion that protrudes radially outward from the outer wall of the inner cylinder; the outer cylinder includes a supporting and limiting protrusion that protrudes radially inward from the inner wall of the first outer cylinder body; the inner cylinder and the outer cylinder are fixedly connected by the matching supporting and positioning protrusion and the supporting and limiting protrusion.

[0016] Optionally, the matching support positioning protrusion and the support limiting protrusion are configured in multiple groups and are evenly distributed along the circumference.

[0017] Optionally, the supporting and limiting protrusion has a groove, the bottom wall of the groove is an axial limiting surface for adapting to the supporting and positioning protrusion, and the two circumferentially opposite sidewalls of the groove are circumferential limiting surfaces for adapting to the supporting and positioning protrusion.

[0018] Optionally, the outer cylinder further includes an auxiliary limiting protrusion, which protrudes radially inward from the inner wall of the first outer cylinder body and is located axially on the side of the supporting limiting protrusion near the opening of the first outer cylinder body, with an axial distance between them. A limiting baffle is provided in the axial distance to axially limit the supporting positioning protrusion. The auxiliary limiting protrusion has an axially penetrating slot so that the supporting positioning protrusion passes through the slot and is adapted to the supporting limiting protrusion. A locking block is provided in the slot, and the locking block and the limiting baffle are fixed by locking bolts.

[0019] Optionally, the limiting baffle has a stop recess on its surface facing the slot, the locking block has a stop protrusion, and the stop protrusion is inserted into the stop recess of the limiting baffle.

[0020] Optionally, the support positioning protrusion and the axial limiting surfaces on both sides have a circumferential distance, and an insert shim is provided in the circumferential distance to circumferentially limit the support positioning protrusion.

[0021] Optionally, the front-mounted steam turbine is a front-mounted steam turbine with a flow passage component at one end and a balance drum at the other end, or a front-mounted steam turbine with flow passage components at both ends.

[0022] The present invention also provides a steam turbine system, the steam turbine system including a front-mounted steam turbine and a main steam turbine, wherein the exhaust steam of the front-mounted steam turbine is delivered to the main steam turbine, and the front-mounted steam turbine is a front-mounted steam turbine suitable for high exhaust pressure as described above.

[0023] Compared with existing technologies, this solution offers a novel approach: a front-mounted steam turbine. Specifically, its outer cylinder is a split structure formed by a second interface perpendicular to the shaft centerline. The opening ends of the first and second outer cylinders have annular flanges and are assembled and fixed by a set of second connecting bolts. Compared with existing technologies, the outer cylinder structure of this application can stably withstand exhaust pressures of tens of megapascals. Simultaneously, two annular skirt sections, along with the outer wall of the inner cylinder and the inner wall of the outer cylinder, form a low-pressure chamber. A pressure balance hole is provided on the cylinder wall of the outer cylinder between the two annular skirt sections, connecting to the low-pressure chamber and thus the low-pressure area of ​​the steam turbine. This maintains a lower pressure within the low-pressure chamber, effectively reducing the axial tensile stress on the second connecting bolts. The pressure isolation mechanism established based on the low-pressure chamber significantly reduces the range of high exhaust pressure, improves the overall pressure-bearing capacity and connection reliability of the outer cylinder, avoids localized stress concentration, and ensures that the outer cylinder of the front-mounted steam turbine can stably withstand very high steam pressures. Attached Figure Description

[0024] Figure 1 A schematic diagram of a front-mounted steam turbine provided for an embodiment of this application;

[0025] Figure 2 for Figure 1 AA section view in the middle;

[0026] Figure 3 for Figure 1 A magnified view of part B in the diagram;

[0027] Figure 4 for Figure 2 A schematic diagram of the outer cylinder shown;

[0028] Figure 5 for Figure 4 CC partial sectional view;

[0029] Figure 6 for Figure 2 A schematic diagram of the inner cylinder shown;

[0030] Figure 7 A schematic diagram showing the circumferential limiting relationship of the supporting positioning protrusion is shown;

[0031] Figure 8 This is a schematic diagram showing the assembly relationship of the limit baffle;

[0032] Figure 9 This is a schematic diagram showing the assembly relationship of the locking blocks;

[0033] Figure 10 This is a schematic diagram of another front-mounted steam turbine provided in an embodiment of this application.

[0034] In the picture:

[0035] Inner cylinder 1, steam inlet chamber 5, first inner cylinder body 1a, second inner cylinder body 1b, first connecting bolt 1c, support positioning protrusion 1d, outer cylinder 2, first outer cylinder body 2a, second outer cylinder body 2b, second connecting bolt 2c, annular skirt 2d, pressure balance hole 2e, support limiting protrusion 2f, axial limiting surface 2f1, auxiliary limiting protrusion 2g, slot 2g1, flow passage component 3, balance drum 4, steam inlet chamber 5, outer wall surface 5a 6. Circular ring; 7. Sealing ring; 8. Low-pressure chamber; 9. Air inlet; 10. Rotor; 11. End steam seal; 12. Positioning device; 13. Exhaust pipe; 14. Fixing device; 15. Rotor center; 16. First interface; 17. Guide arc surface; 18. Guide rounded corner; 19. Limiting baffle; 191. Stopping recess; 20. Locking block; 201. Stopping protrusion; 202. Mounting hole; 21. Locking bolt; 22. Gasket; 15. Center; 23. Second interface. Detailed Implementation

[0036] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] A front-mounted steam turbine is essentially a back-pressure steam turbine, characterized by fewer flow stages and relatively high inlet and outlet steam pressures. In a steam turbine system architecture, the front-mounted steam turbine operates in series with other turbines, such as the main steam turbine. During operation, the front-mounted steam turbine first uses the high-parameter steam to perform energy conversion and work, then delivers the still high-pressure and high-temperature exhaust steam to the subsequent turbines for further expansion and work.

[0038] Typically, a front-mounted steam turbine consists of nested outer and inner cylinders, with the outer cylinder bearing the higher exhaust pressure independently.

[0039] To ensure that the outer cylinder of a front-mounted steam turbine can stably withstand high steam pressure, a systematic optimization and upgrade can be carried out from two aspects: cylinder structure design and material selection. On the one hand, by optimizing the cylinder structure, the pressure load is rationally distributed to avoid local stress concentration; on the other hand, high-strength, high-toughness materials are selected, and the strength parameters of the cylinder, flanges, bolts, and other connecting parts are precisely matched according to the pressure conditions. This ensures that all components work together to bear pressure, effectively preventing sealing failures caused by stress imbalance, and ensuring the long-term stable operation of the steam turbine.

[0040] For units with higher exhaust pressure, conventional solutions include increasing cylinder wall thickness, using high-strength materials, and enlarging bolt sizes to enhance cylinder strength and sealing performance. However, these measures increase cylinder thermal stress during turbine start-up and shutdown, and due to limitations in material properties and thermal stress, it remains difficult to effectively increase the unit's exhaust pressure.

[0041] Please see Figure 1 and Figure 2 ,in, Figure 1 This is a schematic diagram of a front-mounted steam turbine provided in an embodiment of this application. Figure 2 for Figure 1 AA section view in the image.

[0042] The front-mounted steam turbine provided in this application embodiment is suitable for high exhaust pressures, such as, but not limited to, exhaust pressures of 15 MPa or higher. This front-mounted steam turbine employs a double-layer cylinder structure including an inner cylinder 1 and an outer cylinder 2, with a flow passage component 3 at one end and a balance drum 4 at the other end. Both the inner cylinder 1 and the outer cylinder 2 are separate structures.

[0043] like Figure 1 As shown, the outer cylinder 2 is a split structure formed by a second interface 23 perpendicular to the axis. The opening ends of the first outer cylinder body 2a and the second outer cylinder body 2b facing each other have annular flanges and are assembled and fixed by a set of second connecting bolts 2c. Compared with the prior art, the outer cylinder 2 structure of this application can stably withstand exhaust pressure of tens of megapascals.

[0044] like Figure 2 As shown, the inner cylinder 1 is a split structure formed by a first interface through the axis. The first inner cylinder body 1a and the second inner cylinder body 1b are assembled and fixed by a set of first connecting bolts 1c. The middle part of the inner cylinder 1 is an inlet area with an inlet chamber 5. The inlet chamber 5 is formed by the first inner cylinder body 1a and the second inner cylinder body 1b. On the radially opposite sides of the inlet area, there are air inlets 9 that communicate with the inlet chamber 5.

[0045] Here, the outer wall of the inner cylinder 1 does not have a traditional protruding connecting flange, and each of the first connecting bolts 1c is embedded in the cylinder wall (first inner cylinder body 1a and second inner cylinder body 1b) around the steam inlet chamber 5.

[0046] In its specific implementation, both sides of the cylinder wall of the inner cylinder 1 (first inner cylinder body 1a and second inner cylinder body 1b) have reduced diameter sections, which are respectively fixed by interference-fitted rings 6. One ring 6 is fitted onto the reduced diameter section of the cylinder wall on the side where the flow passage component 3 is located, and the other ring 6 is fitted onto the reduced diameter section of the cylinder wall on the side where the balance drum 4 is located. Overall, the two rings 6, in conjunction with the first connecting bolts 1c, reliably fix the first inner cylinder body 1a and the second inner cylinder body 1b.

[0047] like Figure 1As shown, both the first outer cylinder 2a and the second outer cylinder 2b have a "cup-shaped" structure. The inner walls of the first outer cylinder 2a and the second outer cylinder 2b are respectively provided with annular skirt portions 2d, both extending towards the inner cylinder 1 and respectively fitting with the outer peripheral surface of the corresponding ring 6. Multiple sealing rings 7 are embedded in the annular skirt portions 2d, forming a zero-clearance fit between the sealing rings 7 and the outer peripheral surface of the ring 6.

[0048] In other specific implementations, the sealing ring 7 can also be embedded on the outer circumferential surface of the ring 6, which can also form a zero-gap fit between the two. The specific implementation can be determined according to the overall design requirements of the product, and this application embodiment does not limit it.

[0049] In this embodiment, two annular skirt portions 2d, together with the outer wall of the inner cylinder 1 and the inner wall of the outer cylinder 2, form a low-pressure chamber 8. A pressure balance hole 2e is provided on the cylinder wall of the outer cylinder 2 between the two annular skirt portions 2d. The pressure balance hole 2e extends through to the low-pressure chamber 8, connecting to the low-pressure area of ​​the turbine. This maintains a lower pressure within the low-pressure chamber 8, effectively reducing the axial tensile stress on the second connecting bolt. The pressure isolation mechanism established based on the low-pressure chamber 8 significantly reduces the range of high exhaust pressure, improves the overall pressure-bearing capacity and connection reliability of the outer cylinder 2, and avoids localized stress concentration.

[0050] In this embodiment, the pressure balancing hole 2e, which connects to the low-pressure chamber 8, is located on the side of the first inner cylinder 1a. In other possible implementations, the pressure balancing hole 2e may also be located on the side of the second inner cylinder 1b. The specific location can be selected according to the overall product design requirements. As long as an effective pressure isolation mechanism can be established, it is within the scope of protection claimed in this application.

[0051] For the second connecting bolt 2c, which fixes the first outer cylinder 2a and the second outer cylinder 2b, the tensile force it bears is generated by two parts of pressure load: first, from the turbine exhaust pressure P1, which acts on the annular area formed between the outer diameter of the ring 6 and the diameter of the steam seal of the rotor 10; second, from the pressure P2 inside the low-pressure chamber 8, which acts on the annular area between the inner wall diameter of the outer cylinder 1 of the low-pressure chamber 8 and the outer diameter of the ring 6. It can be understood that these two pressures exert forces through different annular areas, jointly determining the stress on the second connecting bolt 2c.

[0052] Taking the two rings 6 having the same outer diameter (R2) and the steam seals on both sides of the rotor 10 having the same diameter (R1) as an example, the force relationship of the second connecting bolt 2c can be expressed by the following formula:

[0053] S=(P1-Pk)×π·(R2 2 - R1 2)+(P2-Pk)×π·(R3 2 - R2 2 );

[0054] Where S is the total tensile force borne by all the second connecting bolts 2c, P1 is the exhaust pressure of the front-mounted steam turbine, P2 is the pressure in the low-pressure chamber, Pk is the atmospheric pressure, R1 is the radius of the rotor steam seal, R2 is the radius of the outer surface of the ring, and R3 is the radius of the inner wall of the outer cylinder.

[0055] In addition, to optimize the available space between the steam inlet chamber 5 of the inner cylinder 1 and the first connecting bolt 1c on the periphery, in a specific implementation, the outer wall of the steam inlet chamber 5 can be designed as an eccentric structure, such as... Figure 2 As shown, the outer wall surface 5a of the intake chamber 5 located on one side of the line connecting the centers of the two intake ports 9 and the outer wall surface 5a of the intake chamber 5 located on the other side of the line connecting the centers of the two intake ports 9 both exhibit a gradually decreasing radial dimension from one intake port 9 to the other; correspondingly, the wall thickness of the inner cylinder 1 exhibits a gradually increasing trend. Simultaneously, the outer wall surface 5a of the intake chamber 5 located on one side of the line connecting the centers of the two intake ports 9 and the outer wall surface 5a of the intake chamber 5 located on the other side of the line connecting the centers of the two intake ports 9 are rotationally symmetrical with respect to the rotor center 15. In other words, the intake ports 9 are respectively located at the misalignment points where the outer wall surface dimensions of the intake chamber 5 change.

[0056] In this embodiment, the first interface 16 between the first inner cylinder 1a and the second inner cylinder 1b is located in a small radial region on the outer wall surfaces 5a on both sides. Figure 2 Taking the horizontal steam inlet structure shown as an example, the first interface 16 of the inner cylinder 1 is arranged obliquely; correspondingly, the first connecting bolt 1c for assembling and fixing the first inner cylinder body 1a and the second inner cylinder body 1b is embedded in the first inner cylinder body 1a and the second inner cylinder body 1b with thicker cylinder walls on both sides of the steam inlet chamber 5.

[0057] Simultaneously, a guide arc surface 17 is provided at the end of the outer wall surface 5a with a smaller radial dimension (thicker cylinder wall), and a guide radius 18 is provided at the end of the outer wall surface 5a with a larger radial dimension (thinner cylinder wall). This guides the steam flow in a predetermined direction ( Figure 2 (As indicated by the middle arrow) flows into the steam inlet chamber 5.

[0058] Furthermore, a stable and reliable locking relationship is required between the inner cylinder 1 and the outer cylinder 2 in both the axial and radial directions. In practice, this locking relationship can be achieved using different structural forms. To improve assembly manufacturability, a locking relationship in both the axial and radial directions can be achieved based on the supporting and positioning protrusion 1d on the inner cylinder 1 side and the supporting and limiting protrusion 2f on the outer cylinder 2 side.

[0059] For example, the supporting positioning protrusion 1d and the supporting limiting protrusion 2f are arranged in a one-to-one correspondence, which can realize the basic axial, radial and circumferential limiting between the inner cylinder 1 and the outer cylinder 2. The supporting positioning protrusion 1d and the supporting limiting protrusion 2f arranged in groups can be evenly distributed in the circumferential direction, for example, but not limited to Figure 2 The figures shown are distributed at equal 90° intervals. Please also refer to... Figure 3 , Figure 4 , Figure 5 and Figure 6 ,in, Figure 3 for Figure 1 A magnified view of part B in the diagram. Figure 4 for Figure 2 A schematic diagram of the outer cylinder shown. Figure 5 for Figure 4 CC partial sectional view, Figure 6 for Figure 2 A schematic diagram of the inner cylinder shown.

[0060] like Figure 3 As shown, based on the corresponding supporting positioning protrusion 1d and supporting limiting protrusion 2f, the locking and fixing structure also includes an auxiliary limiting protrusion 2g provided on the inner wall of the outer cylinder 2, as well as a limiting baffle 19, a locking block 20 and a locking bolt 21.

[0061] Combination Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, both the supporting limiting protrusion 2f and the auxiliary limiting protrusion 2g protrude radially inward from the inner wall of the first outer cylinder 2a. The auxiliary limiting protrusion 2g is located axially on the side of the supporting limiting protrusion 2f closest to the opening of the first outer cylinder 2a, and there is an axial distance L1 between them. The supporting limiting protrusion 2f of the outer cylinder 2 has an axial limiting surface 2f1. The supporting positioning protrusion 1d protrudes radially outward from the outer wall of the inner cylinder 1 and presses against the axial limiting surface 2f1 to form an axial basic limiting. After forming a radial basic limiting through the inner wall of the first outer cylinder 2a, the limiting baffle 19 can be inserted into the axial distance L1 and axially press against the supporting positioning protrusion 1d and the auxiliary limiting protrusion 2g, restricting the supporting positioning protrusion 1d from dislodging. Figure 4 As shown, the auxiliary limiting protrusion 2g has an axially penetrating slot 2g1 so that the supporting positioning protrusion 1d passes through the slot 2g1 and is adapted to the supporting limiting protrusion 2f.

[0062] The supporting and limiting protrusion 2f also includes two opposing circumferential limiting surfaces 2f2. Figure 5The sectional view shown only illustrates one circumferential limiting surface 2f2. In a specific implementation, the supporting and limiting protrusion 2f has a groove, and the axial limiting surface 2f1 and the circumferential limiting surface 2f2 can be formed on the bottom wall and side wall of the groove, respectively. In this way, the supporting and positioning protrusion 1d of the inner cylinder 1 forms an axial basic limiting by pressing against the axial limiting surface 2f1, and after forming a radial basic limiting by the inner wall of the first outer cylinder 2a, the supporting and positioning protrusion 1d can also be circumferentially limited by the two circumferential limiting surfaces 2f2.

[0063] To further improve manufacturability, in the actual implementation, the supporting positioning protrusion 1d and the two axial limiting surfaces 2f1 can have a circumferential distance L2. Please refer to [the relevant documentation]. Figure 7 The figure shows a schematic diagram of the circumferential limiting relationship of the supporting positioning protrusion 1d.

[0064] Combination Figure 7 As shown, the circumferential distance L2 between the supporting positioning protrusion 1d and the two axial limiting surfaces 2f1 facilitates the assembly of the supporting positioning protrusion 1d and the supporting limiting protrusion 2f. After the supporting positioning protrusion 1d of the inner cylinder 1 is pressed against the axial limiting surface 2f1 to form an axial basic limit, a shim 22 can be inserted between the supporting positioning protrusion 1d and the two axial limiting surfaces 2f1. The circumferential basic limit of the supporting positioning protrusion 1d is achieved by inserting two shims 22.

[0065] Please see also Figure 8 and Figure 9 ,in, Figure 8 This is a schematic diagram showing the assembly relationship of the limiting baffle 19. Figure 9 This is a schematic diagram of the assembly relationship of locking block 20.

[0066] After completing the basic positioning of inner cylinder 1 and outer cylinder 2, as follows Figure 8 As indicated by the middle arrow, the limiting baffle 19 can be inserted into the axial distance L1 between the auxiliary limiting protrusion 2g and the supporting positioning protrusion 1d (supporting limiting protrusion 2f). The surface of the limiting baffle 19 facing the slot 2g1 of the auxiliary limiting protrusion 2g has a stop recess 191 for fitting with the locking block 20 and the locking bolt 21.

[0067] After assembling the limit baffle 19, as follows: Figure 9 As indicated by the middle arrow, the locking block 20 can press against the limiting baffle 19, and the locking block 20 abuts against the two circumferentially opposite groove walls of the slot 2g1 of the auxiliary limiting protrusion 2g. The locking block 20 has a stop protrusion 201 and a mounting hole 202. The stop protrusion 201 can be inserted into the stop recess 191 of the limiting baffle 19, and the locking bolt passes through the mounting hole 202 of the locking block 20 and is threadedly matched with the bottom of the stop recess 191 of the limiting baffle 19, thereby fixing the limiting baffle 19.

[0068] In this way, based on the circumferentially distributed support positioning protrusions 1d and support limiting protrusions 2f, supplemented by the limiting baffle 19, locking block 20 and gasket 22 cooperating and restraining each other, the center 15 of the inner cylinder 1 and the outer cylinder 2 are kept consistent. The inner cylinder 1 can only expand or contract radially relative to the outer cylinder 2, and cannot produce axial or radial displacement. Through this positioning method, it is effectively ensured that the inner cylinder 1 and the outer cylinder 2 always remain concentric.

[0069] The following is a brief explanation. Figure 1 The installation process for the front-mounted steam turbine is described as follows:

[0070] First, assemble the inner cylinder 1 and rotor 10, pre-fixing both ends of the inner cylinder 1 to the rotor 10 using positioning devices 12. Then, use a crane to vertically lift the pre-fixed rotor 10 and inner cylinder 1 as a whole, simultaneously placing and fixing the first outer cylinder body 2a of the outer cylinder 2 with its open end facing upwards. In this state, install the lower end steam seal 11 inside the first outer cylinder body 2a. Next, remove the positioning devices 12 on the lower side of the inner cylinder 1 and rotor 10, and lower them vertically into the first outer cylinder body 2a. In this state, the supporting positioning protrusion 1d of the inner cylinder 1 and the supporting limiting protrusion 2f of the first outer cylinder body 2a are tightly fitted, achieving radial and axial positioning. The inner cylinder 1 and the first outer cylinder body 2a are assembled and fixed using limiting baffles 19, locking blocks 20, and gaskets 22. Then, take reliable padding measures at the bottom of the rotor 10 (not shown in the figure), and remove the positioning devices 12 on the upper side of the rotor 10 and inner cylinder 1. Finally, the upper end steam seal 11 and the second outer cylinder 2b are installed using special tools. After the second connecting bolt 2c of the outer cylinder 1 is tightened, the fixing device 14 between the rotor 10 and the outer cylinder 2 is installed at both ends of the cylinder. Based on this fixing device 14, the entire cylinder module can be flipped from vertical to horizontal, and the overall relocation and transportation functions can also be met.

[0071] It should be understood that the specific implementation of the functions of the flow passage component 3, balance drum 4, rotor 10 and end steam seal 11 described in this embodiment is not the core inventive point of this application. Those skilled in the art can implement it based on the existing technology, so it will not be described in detail here.

[0072] Besides the aforementioned front-mounted steam turbine with a flow passage component at one end and a balance drum at the other, the inner and outer cylinder structures provided in the aforementioned embodiments can also be used in steam turbines with a dual-flow-diverting structure. Please refer to... Figure 10 This figure is a schematic diagram of another front-mounted steam turbine provided in an embodiment of this application. To clearly illustrate the difference between this embodiment and... Figure 1 The differences and connections between the described implementation schemes, as well as the components and structures with the same functions, are illustrated in the diagram using the same symbols.

[0073] and Figure 1Compared to the described implementation scheme, the difference in this implementation scheme is that flow passage components 3 are respectively installed at both ends of the front-mounted steam turbine. Correspondingly, the exhaust pipes 13 on both sides are interconnected (not shown in the figure) to ensure that the flow passage components at both ends obtain the same exhaust pressure.

[0074] The specific structure of other functional components can be adopted in accordance with... Figure 1 The implementation method is consistent with the described embodiments. It will not be repeated here.

[0075] In addition to the aforementioned front-mounted steam turbine, embodiments of this application also provide a steam turbine system, which includes the aforementioned components. Figure 1 or Figure 2 The described front-mounted steam turbine also includes a main steam turbine connected in series with the front-mounted steam turbine, and the exhaust steam from the front-mounted steam turbine is delivered to the main steam turbine.

[0076] In practice, the thermodynamic and mechanical coupling between the front-mounted steam turbine and the main steam turbine can be achieved using existing technologies, so they will not be elaborated further.

[0077] Furthermore, the ordinal numbers "first" and "second," etc., used herein are only for describing the composition or structure of the same function in the technical solution. It is understood that the use of the aforementioned ordinal numbers does not constitute a limitation on the understanding of the technical solution for which protection is sought in this application.

[0078] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A front-mounted steam turbine suitable for high exhaust pressure, characterized in that, The front-mounted steam turbine includes a nested outer cylinder (2) and an inner cylinder (1). Both the outer cylinder (2) and the inner cylinder (1) are split structures. The inner cylinder (1) includes a first inner cylinder body (1a) and a second inner cylinder body (1b) formed by a first interface (16) through the axis. The first inner cylinder body (1a) and the second inner cylinder body (1b) are fixedly connected by a first connecting bolt (1c) embedded in the cylinder body. The outer cylinder (2) includes a first outer cylinder body (2a) and a second outer cylinder body (2b) formed by a second interface (23) perpendicular to the axis. The opening ends of the first outer cylinder body (2a) and the second outer cylinder body (2b) facing each other have annular flanges, which are fixedly connected by a second connecting bolt (2c) passing through the two annular flanges. Both sides of the cylinder walls of the first inner cylinder (1a) and the second inner cylinder (1b) have reduced diameter sections, which are respectively fixed by interference fit rings (6); The inner wall surfaces of the first outer cylinder (2a) and the second outer cylinder (2b) are respectively provided with annular skirt portions (2d), both of which extend toward the inner cylinder (1) and are adapted to the outer peripheral surface of the corresponding ring (6); The two annular skirt portions (2d) together with the outer wall of the inner cylinder (1) and the inner wall of the outer cylinder (2) form a low-pressure chamber (8). The cylinder wall of the outer cylinder (2) is provided with a pressure balance hole (2e) that extends to the low-pressure chamber (8). The pressure balance hole (2e) is used to connect the low-pressure area.

2. The front-mounted steam turbine according to claim 1, characterized in that, The pressure balance hole (2e) is formed on the cylinder wall of the first outer cylinder (2a).

3. The front-mounted steam turbine according to claim 1 or 2, characterized in that, The annular skirt portion (2d) and the outer peripheral surface of the corresponding ring (6) are fitted with zero clearance by a sealing ring (7).

4. The front-mounted steam turbine according to claim 1 or 2, characterized in that, The first inner cylinder (1a) and the second inner cylinder (1b) enclose an air intake chamber (5), and air inlets (9) communicating with the air intake chamber (5) are respectively located on the radially opposite sides of the air intake chamber (5). The outer wall surface (5a) of the steam inlet chamber (5) located on one side of the line connecting the centers of the two air inlets (9) and the outer wall surface (5a) of the steam inlet chamber (5) located on the other side of the line connecting the centers of the two air inlets (9) both have radial dimensions that gradually decrease from one side of the air inlet (9) toward the other side of the air inlet (9). Correspondingly, the cylinder wall thickness of the inner cylinder (1) gradually increases. The outer wall surface (5a) located on one side of the line connecting the centers of the two air inlets (9) and the outer wall surface (5a) located on the other side of the line connecting the centers of the two air inlets (9) are rotationally symmetrical with respect to the rotor center (15). The first interface (16) is located in the radially small area of ​​the outer wall surface (5a) on both sides, and the first connecting bolt (1c) is embedded in the cylinder wall on both sides with a thicker wall thickness corresponding to the radially small area.

5. The front-mounted steam turbine according to claim 4, characterized in that, The outer wall surface (5a) has a guide arc surface (17) at one end with a smaller radial dimension and a guide fillet (18) at the other end with a larger radial dimension.

6. The front-mounted steam turbine according to claim 1, characterized in that, The inner cylinder (1) includes a support positioning protrusion (1d) that protrudes radially outward from the outer wall of the inner cylinder (1); the outer cylinder (2) includes a support limiting protrusion (2f) that protrudes radially inward from the inner wall of the first outer cylinder body (2a); the inner cylinder (1) and the outer cylinder (2) are fixedly connected by the matching support positioning protrusion (1d) and support limiting protrusion (2f).

7. The front-mounted steam turbine according to claim 6, characterized in that, The matching support positioning protrusion (1d) and the support limiting protrusion (2f) are configured in multiple groups and are evenly distributed along the circumference.

8. The front-mounted steam turbine according to claim 6 or 7, characterized in that, The support limiting protrusion (2f) has a groove, the bottom wall of the groove is an axial limiting surface (2f1) for adapting to the support positioning protrusion (1d), and the two circumferentially opposite sidewalls of the groove are circumferential limiting surfaces (2f2) for adapting to the support positioning protrusion (1d).

9. The front-mounted steam turbine according to claim 8, characterized in that, The outer cylinder (2) further includes an auxiliary limiting protrusion (2g), which protrudes radially inward from the inner wall of the first outer cylinder body (2a) and is located axially on the opening side of the support limiting protrusion (2f) near the first outer cylinder body (2a), and there is an axial distance (L1) between the two. A limiting baffle (19) is provided in the axial distance (L1) to axially limit the support positioning protrusion (1d). The auxiliary limiting protrusion (2g) has an axially penetrating slot (2g1) so that the support positioning protrusion (1d) passes through the slot (2g1) and is adapted to the support limiting protrusion (2f). A locking block (20) is provided in the slot (2g1), and the locking block (20) and the limiting baffle (19) are fixed by locking bolts (21).

10. The front-mounted steam turbine according to claim 9, characterized in that, The limiting baffle (19) has a stop recess (191) on the surface facing the slot (2g1), and the locking block (20) has a stop protrusion (201), and the stop protrusion (201) is inserted into the stop recess (191) of the limiting baffle (19).

11. The front-mounted steam turbine according to claim 8, characterized in that, The support positioning protrusion (1d) and the axial limiting surfaces (2f1) on both sides have a circumferential distance (L2), and an insert gasket (22) is provided in the circumferential distance (L2) to circumferentially limit the support positioning protrusion (1d).

12. The front-mounted steam turbine according to claim 1, characterized in that, The front-mounted steam turbine is a front-mounted steam turbine with a flow passage component (3) at one end and a balance drum (4) at the other end, or a front-mounted steam turbine with flow passage components (3) at both ends.

13. A steam turbine system, characterized in that, The turbine system includes a front-mounted turbine and a main turbine, wherein the exhaust steam from the front-mounted turbine is delivered to the main turbine, and the front-mounted turbine is a front-mounted turbine suitable for high exhaust pressure as described in any one of claims 1 to 12.

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