High-pressure cylinder nozzle block and steam inlet structure for medium-sized steam turbine

Abstract

A high-pressure cylinder nozzle block for a medium-sized steam turbine and a steam admission structure belong to the technical field of steam turbines, the nozzle block is peripherally provided with three areas, the area X is provided with a plurality of nozzles M, the area Y is provided with a plurality of nozzles N, the area Z is provided with a plurality of nozzles M. Partition blocks are respectively arranged among the areas, and the partition blocks are connected with partition ribs of a high-pressure inner cylinder. A balance hole is formed in the partition block and communicated with cavities on the two sides of the regulating stage impeller of the high-pressure inner cylinder, so that the pressure difference of steam on the two sides of the regulating stage impeller is reduced, overlarge axial force generated by a rotor is reduced, the strength of the regulating stage impeller is not weakened, and air leakage loss is reduced; and the nozzle set is formed by assembling the independently-milled nozzle M, the independently-milled nozzle N and the separation block, the partial steam admission degree is 92.7% and is higher than that of a traditional unit, and the economical efficiency of the steam turbine is improved.

Description

Technical Field

[0001] The invention relates to the technical field of steam turbines, and in particular to a high-pressure cylinder nozzle group and a steam inlet structure for a medium-sized steam turbine. Background Art

[0002] The nozzle group is one of the important components of the internal flow part of the steam turbine. Its main function is to cooperate with the regulating valve to realize the nozzle steam distribution of the steam turbine.

[0003] Disadvantages of existing high-pressure cylinder nozzle groups and steam inlet structures for medium-sized steam turbines:

[0004] 1. The nozzle group adopts a single milled nozzle blade, which is welded to the inner and outer bands of the punched stationary blade, and then welded to the inner and outer bands of the nozzle group. This causes welding deformation of the nozzle group structure, and the steam channel size cannot be guaranteed. The partial steam inlet degree is 80%, and the economy is poor.

[0005] 2. Opening a balancing hole directly on the regulating stage impeller weakens the strength of the regulating stage impeller, increases air leakage loss, increases the pressure difference of steam on both sides of the regulating stage impeller, and increases the excessive axial force generated by the rotor.

[0006] 3. The inner end of the regulating valve seat is not directly connected to the inner cylinder, and the steam contacts the outer cylinder, resulting in steam leakage at the connection of the regulating valve. Summary of the invention

[0007] The purpose of the present invention is to provide a high-pressure cylinder nozzle group and a steam inlet structure for a medium-sized steam turbine in view of the deficiencies of the prior art. The technical solution adopted is as follows:

[0008] A nozzle group for a high-pressure cylinder of a medium-sized steam turbine, the nozzle group is assembled on a nozzle chamber, and the nozzle chamber is cast together with a high-pressure inner cylinder, the nozzle group is provided with three areas around the entire circumference, including area X, area Y and area Z; area X is provided with a plurality of nozzles M, area Y is provided with a plurality of nozzles N, and area Z is provided with a plurality of nozzles M; between area X and area Y, between area X and area Z, and between area Y and area Z, a partition block is provided respectively, and the nozzle M, the nozzle N and the partition block are separately milled according to their own profiles.

[0009] Furthermore, the nozzle M, the nozzle N and the separation block are all made of 1Cr11MoV heat-resistant stainless steel.

[0010] Furthermore, the nozzle group is distributed in 96 equal parts around the entire circumference, wherein 58 nozzles M, 32 nozzles N and 89 steam channels are arranged, and the steam admission degree of the nozzle group is 89 / 96=92.7%.

[0011] Furthermore, the nozzle M includes a guide vane M and an outer ring and an inner ring. The guide vane M is integrally arranged with the outer ring and the inner ring, and a steam passage is formed between the two guide vanes M.

[0012] Furthermore, the nozzle N includes a guide vane N and an outer ring and an inner ring. The guide vane N is integrally arranged with the outer ring and the inner ring, and a steam passage is formed between the two guide vanes N.

[0013] Furthermore, the first nozzle N on the left side of the upper half of the entire circumference of the nozzle group is the first nozzle N, and the last nozzle M on the right side is the last nozzle M, and sealing cylindrical pins are provided on the first nozzle N and the last nozzle M.

[0014] Furthermore, the first nozzle M on the left side of the lower half of the entire circumference of the nozzle group is the first nozzle M, and the last nozzle N on the right side is the last nozzle N, and sealing cylindrical pins are provided on both the first nozzle M and the last nozzle N.

[0015] Furthermore, the partition block is connected to the partition rib of the high-pressure inner cylinder.

[0016] Furthermore, a balancing hole is provided on the partition block, and the balancing hole is connected to the chambers on both sides of the impeller of the high-pressure inner cylinder regulating stage.

[0017] A steam inlet structure for a high-pressure cylinder of a medium-sized steam turbine comprises three regulating valves and a nozzle group for a high-pressure cylinder of a medium-sized steam turbine. The three regulating valves are all arranged on the upper part of the high-pressure cylinder. The diffusers at the lower ends of the valve seats of the three regulating valves are connected to the high-pressure inner cylinder, and the nozzle chamber is cast together with the high-pressure inner cylinder. The nozzle group is assembled on the nozzle chamber, and steam enters the nozzle group through the diffusers at the lower ends of the valve seats of the regulating valves.

[0018] The beneficial effects of the present invention are:

[0019] 1. The assembled technology design is adopted, and the nozzle group structure has no welding deformation, which can ensure the size of the steam channel. The nozzle group is composed of separately milled nozzles M and N and a separator block assembly. The partial steam inlet degree is 92.7%, which is higher than that of traditional units, which improves the efficiency and the economy of the steam turbine.

[0020] 2. The partition block is connected to the partition ribs of the high-pressure inner cylinder. A balancing hole is provided on the partition block. The balancing hole connects the chambers on both sides of the regulating stage impeller of the high-pressure inner cylinder, reducing the pressure difference of the steam on both sides of the regulating stage impeller, reducing the excessive axial force generated by the rotor, preventing the strength of the regulating stage impeller from being weakened, and reducing the leakage loss.

[0021] 3. All three regulating valves are arranged on the upper part of the high-pressure cylinder. The high-pressure inner cylinder and the nozzle chamber are cast together. The nozzle group is assembled on the nozzle chamber. The steam enters the nozzle group through the diffuser at the lower end of the regulating valve seat, which reduces the air leakage loss and further improves the steam intake efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solution of the present invention, the accompanying drawings required for use in the description will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0023] Figure 1 2 is a schematic structural diagram of a high-pressure cylinder nozzle assembly according to a specific embodiment of the present invention;

[0024] Figure 2 yes Figure 1 The upper part of the expanded view - Q view;

[0025] Figure 3 yes Figure 1 The lower half of the expanded view - S view;

[0026] Figure 4 yes Figure 1 Sectional view of AA in the middle;

[0027] Figure 5 yes Figure 1 Cross-sectional view of the middle BB;

[0028] Figure 6 yes Figure 1 Center section C view;

[0029] Figure 7 yes Figure 1 D view of the middle plane;

[0030] Figure 8 yes Figure 1 Middle section E view;

[0031] Fig. 9 yes Figure 1 View of the middle plane F;

[0032] Fig.10 yes Figure 1 Median G view;

[0033] Fig.11 yes Figure 1 Middle plane H view;

[0034] Fig.12 yes Figure 1 Center section I view;

[0035] Fig.13 yes Figure 1 Median J view;

[0036] Fig.14 It is a schematic diagram of the high-pressure cylinder steam inlet structure of a specific embodiment of the present invention.

[0037] 1. Nozzle M; 2. Nozzle N; 3. Separator block; 4. Sealing cylindrical pin; 5. Outer ring; 6. Inner ring; 7. Guide vane M; 8. Guide vane N; 9. Steam channel; 10. Control valve; 11. High-pressure inner cylinder; 12. Diffuser; 13. Nozzle group; 14. Balance hole; 15. Partition rib; 16. First nozzle M; 17. Last nozzle M; 18. First nozzle N; 19. Last nozzle N; 20. Area X; 21. Area Y; 22. Area Z. DETAILED DESCRIPTION

[0038] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings in this specific embodiment. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of them. Based on the embodiments in this patent, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this patent.

[0039] Reference Figure 1-14 , combined with a specific embodiment, it is described as follows: a high-pressure cylinder nozzle group for a medium-sized steam turbine of the present invention, the nozzle group 13 is assembled on the nozzle chamber, and the nozzle chamber is cast together with the high-pressure inner cylinder 11, and the nozzle group 13 is provided with three areas around the entire circumference, including area X20, area Y21 and area Z22; area X20 is provided with multiple nozzles M1, area Y21 is provided with multiple nozzles N2, and area Z22 is provided with multiple nozzles M1; partition blocks 3 are respectively provided between area X20 and area Y21, between area X20 and area Z22, and between area Y21 and area Z22, and the nozzle M1, the nozzle N2 and the partition block 3 are respectively milled separately according to their own profiles.

[0040] Specifically, the nozzle M1, the nozzle N2 and the partition block 3 are all made of 1Cr11MoV heat-resistant stainless steel.

[0041] Specifically, the nozzle group 13 is distributed in 96 equal parts around the entire circumference, wherein 58 nozzles M1, 32 nozzles N2 and 89 steam channels 9 are provided, and the steam admission degree of the nozzle group 13 is 89 / 96=92.7%.

[0042] Specifically, the nozzle M1 includes a guide vane M7, an outer ring 5 and an inner ring 6. The guide vane M7 is integrally provided with the outer ring 5 and the inner ring 6, and a steam passage 9 is formed between the two guide vanes M7.

[0043] Specifically, the nozzle N2 includes a guide vane N8, an outer ring 5 and an inner ring 6. The guide vane N8 is integrally provided with the outer ring 5 and the inner ring 6, and a steam passage 9 is formed between the two guide vanes N8.

[0044] For details, see Figure 2The first nozzle N2 on the left side of the upper half of the entire circumference of the nozzle group 13 is the first nozzle N18, and the last nozzle M1 on the right side is the last nozzle M17. The first nozzle N18 and the last nozzle M17 are both provided with sealing cylindrical pins 4 and are fixed by the sealing cylindrical pins 4.

[0045] For details, see Figure 3 The first nozzle M1 on the left side of the lower half of the entire circumference of the nozzle group 13 is the first nozzle M16, and the last nozzle N2 on the right side is the last nozzle N19. The first nozzle M16 and the last nozzle N19 are both provided with sealing cylindrical pins 4 and are fixed by the sealing cylindrical pins 4.

[0046] In one embodiment, referring to Figure 2 and Figure 5 , the partition block 3 is connected to the partition rib 15 of the high-pressure inner cylinder 11. A balancing hole 14 is provided on the partition block 3. This design avoids directly providing the balancing hole 14 on the regulating stage impeller, ensures the strength of the regulating stage impeller, and reduces the leakage loss. The balancing hole 14 is connected to the chambers on both sides of the regulating stage impeller of the high-pressure inner cylinder 11. This design reduces the pressure difference of the steam on both sides of the regulating stage impeller and prevents the rotor from generating excessive axial force.

[0047] A medium-sized steam turbine high-pressure cylinder steam inlet structure, refer to Fig.14 , including three regulating valves 10 and a high-pressure cylinder nozzle group for a medium-sized steam turbine, wherein the three regulating valves 10 are arranged on the upper part of the high-pressure cylinder, the diffusers 12 at the lower ends of the valve seats of the three regulating valves 10 are connected to the high-pressure inner cylinder 11, and the nozzle chamber is cast together with the high-pressure inner cylinder 11, and the nozzle group 13 is assembled on the nozzle chamber, and the steam enters the nozzle group 13 through the diffuser 12 at the lower end of the valve seat of the regulating valve 10 to reduce steam leakage loss.

[0048] In the actual manufacturing process, the nozzle M1, the nozzle N2 and the partition block 3 are all made of Cr11MoV heat-resistant stainless steel. The nozzle M1 and the nozzle N2 are milled separately, the guide vane M7 is milled according to its profile, the guide vane N8 is milled according to its profile, and the partition block 3 is milled according to its profile. At the same time, the nozzle group 13 is finally assembled in the high-pressure inner cylinder 11 using assembly technology, and the nozzle group 13 has no welding deformation, so that the size of the steam channel 9 can be guaranteed.

[0049] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referenced to each other.

[0050] The terms "upper", "lower", "left", "right", "outer side", "inner side", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish the relative relationship in position if they exist, and do not need to be qualitative. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0051] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high-pressure cylinder nozzle assembly for a medium-sized steam turbine, characterized in that: The nozzle group (13) is assembled on the nozzle chamber, and the nozzle chamber is cast together with the high-pressure inner cylinder (11). The nozzle group (13) is provided with three areas around the entire circumference, including an area X (20), an area Y (21) and an area Z (22); the area X (20) is provided with a plurality of nozzles M (1), the area Y (21) is provided with a plurality of nozzles N (2), and the area Z (22) is provided with a plurality of nozzles M (1); a partition block (3) is provided between the area X (20) and the area Y (21), between the area X (20) and the area Z (22), and between the area Y (21) and the area Z (22), and the nozzle M (1), the nozzle N (2) and the partition block (3) are respectively milled separately according to their own molding lines.

2. A nozzle assembly for a high-pressure cylinder of a medium-sized steam turbine according to claim 1, characterized in that: The nozzle M (1), the nozzle N (2) and the partition block (3) are all made of 1Cr11MoV heat-resistant stainless steel.

3. A nozzle assembly for a high-pressure cylinder of a medium-sized steam turbine according to claim 1, characterized in that: The nozzle group (13) is distributed in 96 equal parts around the entire circumference, wherein 58 nozzles M (1) and 32 nozzles N (2) and 89 steam channels (9) are arranged. The steam admission degree of the nozzle group (13) is 89 / 96=92.7%.

4. A nozzle assembly for a high-pressure cylinder of a medium-sized steam turbine according to claim 3, characterized in that: The nozzle M (1) comprises a guide vane M (7), an outer ring (5) and an inner ring (6); the guide vane M (7) is integrally arranged with the outer ring (5) and the inner ring (6), and a steam passage (9) is formed between the two guide vanes M (7).

5. The high-pressure cylinder nozzle assembly for a medium-sized steam turbine according to claim 3, characterized in that: The nozzle N (2) comprises a guide vane N (8), an outer ring (5) and an inner ring (6). The guide vane N (8) is integrally arranged with the outer ring (5) and the inner ring (6), and a steam passage (9) is formed between the two guide vanes N (8).

6. A nozzle assembly for a high-pressure cylinder of a medium-sized steam turbine according to claim 1, characterized in that: The first nozzle N (2) on the left side of the upper half of the entire circumference of the nozzle group (13) is the first nozzle N (18), and the last nozzle M (1) on the right side is the last nozzle M (17), and sealing cylindrical pins (4) are provided on both the first nozzle N (18) and the last nozzle M (17).

7. The high-pressure cylinder nozzle assembly for a medium-sized steam turbine according to claim 1, characterized in that: The first nozzle M (1) on the left side of the lower half of the entire circumference of the nozzle group (13) is the first nozzle M (16), and the last nozzle N (2) on the right side is the last nozzle N (19), and sealing cylindrical pins (4) are provided on both the first nozzle M (16) and the last nozzle N (19).

8. The high-pressure cylinder nozzle assembly for a medium-sized steam turbine according to claim 1, characterized in that: The partition block (3) is connected to the partition rib (15) of the high-pressure inner cylinder (11).

9. A nozzle assembly for a high-pressure cylinder of a medium-sized steam turbine according to claim 8, characterized in that: A balancing hole (14) is provided on the partition block (3), and the balancing hole (14) is connected to the chambers on both sides of the regulating stage impeller of the high-pressure inner cylinder (11).

10. A steam inlet structure for a high-pressure cylinder of a medium-sized steam turbine, characterized in that: The invention comprises three regulating valves (10) and a high-pressure cylinder nozzle group for a medium-sized steam turbine as claimed in any one of claims 1 to 9, wherein the three regulating valves (10) are all arranged at the upper part of the high-pressure cylinder, the diffusers (12) at the lower ends of the valve seats of the three regulating valves (10) are connected to the high-pressure inner cylinder (11), and the nozzle chamber and the high-pressure inner cylinder (11) are cast together, the nozzle group (13) is assembled on the nozzle chamber, and the steam enters the nozzle group (13) through the diffusers (12) at the lower ends of the valve seats of the regulating valves (10).

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