Split type supporting and positioning device for low-pressure inner cylinder of steam turbine

Abstract

The application discloses a split type support positioning device for a low-pressure inner cylinder of a steam turbine, wherein the low-pressure inner cylinder of the steam turbine is formed by splicing an upper half of the inner cylinder and a lower half of the inner cylinder and the splicing position is connected through a middle split surface flange; the support positioning device comprises support positioning assemblies connected with the front and rear middle split surface flanges respectively; the front side support positioning assembly comprises left and right support arms fixedly connected with the front side middle split surface flange and an axial positioning block between the left and right support arms; the axial positioning block is fixedly connected with the front side middle split surface flange through a plurality of rib plates and is clamped on a front side outer cylinder support frame to axially position the low-pressure inner cylinder of the steam turbine; and the left and right support arms are arranged on the front side outer cylinder support frame. The axial positioning block, the left support arm and the right support arm are designed in a split type, so that the thermal expansion of the steam inlet area of the low-pressure inner cylinder of the steam turbine with high steam inlet temperature is uniform and continuous, thereby reducing the occurrence of local stress concentration.

Description

Technical Field

[0001] This invention belongs to the field of steam turbine technology, specifically relating to a split-type support and positioning device for the low-pressure inner cylinder of a steam turbine. Background Technology

[0002] The low-pressure inner cylinder of the steam turbine is composed of a semi-cylindrical upper cylinder and a lower cylinder, connected at the joint by a center-part flange. Lateral support is one method of supporting the low-pressure inner cylinder; specifically, the two center-part flanges of the low-pressure inner cylinder are connected to a support and positioning device to achieve support and positioning.

[0003] In existing technologies, for turbine low-pressure inner cylinder units using lateral support, if the axial positioning component of the turbine low-pressure inner cylinder is located in the high-temperature region of the turbine low-pressure inner cylinder, the support arm, axial positioning component, and center-split flange of the turbine low-pressure inner cylinder adopt an integral structure, i.e., the three are designed as a single unit. This increases the rigidity of the center-split flange, but it is only suitable for operating conditions where the steam inlet temperature of the turbine low-pressure inner cylinder is not high and the thermal expansion deformation is small, such as when the steam inlet temperature is below 320℃. When the steam inlet temperature of the turbine low-pressure inner cylinder is high and the thermal expansion is large, such as when the steam inlet temperature is between 360-380℃, it will cause poor thermal expansion in the steam inlet area of ​​the turbine low-pressure inner cylinder, resulting in local stress concentration in the turbine low-pressure inner cylinder.

[0004] Chinese patent CN102140940B discloses a ground-mounted structure for a low-pressure module of a high-power half-speed steam turbine unit. The supporting device of this patent includes a connecting block and a crank arm connected to each other. The connecting block is fixedly connected to the outer wall of the low-pressure inner cylinder. One end of the crank arm is fixed to the turbine operating platform foundation, and the other end passes through a corresponding mounting hole on the side wall of the low-pressure outer cylinder and is fixedly connected to the connecting block. In this patent, the crank arm, connecting block, and low-pressure inner cylinder adopt an integral structure, i.e., an integrated design. This increases the rigidity of the center flange of the low-pressure inner cylinder. When the inlet steam temperature of the turbine's low-pressure inner cylinder is high and thermal expansion is large, it can cause poor thermal expansion in the inlet area of ​​the turbine's low-pressure inner cylinder, resulting in localized stress concentration in the low-pressure inner cylinder. Therefore, there is room for further optimization of the existing technology. Summary of the Invention

[0005] In view of the above-mentioned deficiencies of the prior art, the present invention provides a split support and positioning device for the low-pressure inner cylinder of a steam turbine, which enables uniform and continuous thermal expansion in the steam inlet area of ​​the low-pressure inner cylinder of a steam turbine with high steam inlet temperature, thereby reducing the occurrence of local stress concentration.

[0006] The technical solution adopted by this invention to solve its technical problem is:

[0007] A split-type support and positioning device for a low-pressure inner cylinder of a steam turbine is disclosed. The low-pressure inner cylinder is formed by splicing an upper half and a lower half of the inner cylinder, with the splice connected by a center-part flange. The support and positioning device includes support and positioning components connected to the front and rear center-part flanges respectively. The front support and positioning component includes a left support arm and a right support arm fixedly connected to the front center-part flange, and an axial positioning block located between the left and right support arms. The axial positioning block is fixedly connected to the front center-part flange through multiple ribs and is engaged on the front outer cylinder bracket for axial positioning of the low-pressure inner cylinder of the steam turbine. Both the left and right support arms are placed on the front outer cylinder bracket.

[0008] Furthermore, the left and right support arms are symmetrically arranged on the left and right sides relative to the vertical centerline of the steam inlet at the top of the low-pressure inner cylinder of the steam turbine, and the rear support positioning assembly and the front support positioning assembly are symmetrically arranged front and rear.

[0009] Furthermore, the outer cylinder bracket on the front side is provided with an outer cylinder axial positioning flange at the rear. The axial positioning block is provided with a locking notch at the front middle part, which is adapted to the shape and size of the outer cylinder axial positioning flange. The outer cylinder axial positioning flange is locked in the locking notch. The left support arm is placed on the left side of the front outer cylinder bracket, and the right support arm is placed on the right side of the front outer cylinder bracket.

[0010] Furthermore, a horizontal support plate is provided at the rear of the outer cylinder bracket on the front side. The axial positioning flange of the outer cylinder is located at the front center of the top of the support plate. The right end face of the left support arm is adjacent to the left side face of the axial positioning block, and the left end face of the right support arm is adjacent to the right side face of the axial positioning block. The connection positions of the left and right support arms with the front center flange are both located in the low-temperature region of the low-pressure inner cylinder of the turbine. The left support arm is located at the left side of the top surface of the support plate, and the right support arm is located at the right side of the top surface of the support plate.

[0011] Furthermore, an L-shaped left pad is fitted in the gap between the left side of the outer cylinder axial positioning flange and the left side of the locking notch. The horizontal top plate of the left pad is placed on the left side of the top surface of the axial positioning block and is fixedly connected to the axial positioning block. An L-shaped right pad is fitted in the gap between the right side of the outer cylinder axial positioning flange and the right side of the locking notch. The horizontal top plate of the right pad is placed on the right side of the top surface of the axial positioning block and is fixedly connected to the axial positioning block.

[0012] Furthermore, the left and right support arms are arranged at a certain distance from the axial positioning block, and the connection positions of the left and right support arms and the front split flange are both located in the low-temperature region of the turbine's low-pressure inner cylinder.

[0013] Furthermore, the rear side of the axial positioning block is fixedly connected to the front split flange through two left and right ribs. The left rib and the right rib are symmetrically arranged on the left and right sides relative to the vertical center line of the steam inlet at the top of the low-pressure inner cylinder of the steam turbine, and the left rib is inclined to the left rear side.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0015] The turbine low-pressure inner cylinder support and positioning device of the present invention separates the axial positioning block from the left and right support arms, thereby disconnecting and separating the left and right support arms from the axial positioning block. This reduces the stiffness of the split flange and ensures uniform and continuous thermal expansion of the steam inlet area of ​​the turbine low-pressure inner cylinder, especially the high-temperature steam inlet cavity, and the entire surrounding plate and the split flange, thus reducing the occurrence of excessive local stress concentration.

[0016] In this invention, the rear side of the axial positioning block is fixedly connected to the front split flange via two left and right ribs. The left and right ribs are symmetrically arranged with respect to the vertical centerline of the steam inlet at the top of the low-pressure inner cylinder of the turbine, with the left rib inclined to the left rearward direction. In this way, the axial positioning block, the left rib, the right rib, and the split flange are arranged in an isosceles trapezoidal shape. This ensures the rigidity of the axial positioning block while minimizing the change in the radial rigidity of the low-pressure inner cylinder of the turbine, making the thermal expansion of the steam inlet area of ​​the low-pressure inner cylinder of the turbine, which has a high steam inlet temperature, uniform and continuous, thereby reducing the occurrence of local stress concentration.

[0017] In this invention, the connection positions of the left and right support arms with the front split flange are both located in the low-temperature region of the turbine's low-pressure inner cylinder. This optimizes the connection positions of the left and right support arms with the front split flange, avoiding the connection positions of the left and right support arms with the front split flange being located in the high-temperature region of the turbine's low-pressure inner cylinder, thereby reducing the impact on the uniformity and continuity of thermal expansion in the high-temperature region of the turbine's low-pressure inner cylinder. Attached Figure Description

[0018] Figure 1 This is a three-dimensional structural schematic diagram of the turbine low-pressure inner cylinder support and positioning device according to Embodiment 1 of the present invention;

[0019] Figure 2 for Figure 1 A top view of the connection between the front support and positioning assembly and the front split flange.

[0020] Figure 3 for Figure 1 A partially enlarged structural diagram;

[0021] Figure 4 for Figure 3 A schematic diagram of the structure of the hidden front outer cylinder bracket from another direction;

[0022] Figure 5 This is a three-dimensional structural schematic diagram of the turbine low-pressure inner cylinder support and positioning device according to Embodiment 2 of the present invention;

[0023] Figure 6 for Figure 5 A top view of the connection between the front support and positioning assembly and the front split flange.

[0024] Figure 7 for Figure 5 A partially enlarged structural diagram;

[0025] Figure 8 for Figure 7 A schematic diagram of the structure of the hidden front outer cylinder bracket.

[0026] The following are the annotations in the figure: 101, upper half of the inner cylinder; 102, lower half of the inner cylinder; 103, center split flange; 104, steam inlet; 201, left support arm; 202, right support arm; 3, axial positioning block; 301, locking notch; 4, rib plate; 5, outer cylinder bracket; 501, support plate; 502, outer cylinder axial positioning flange; 601, left pad block; 602, right pad block. Detailed Implementation

[0027] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0028] In the description of this invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element 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 the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0029] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0030] Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0031] like Figure 1-8 As shown, a split-type support and positioning device for the low-pressure inner cylinder of a steam turbine is disclosed. The low-pressure inner cylinder is formed by splicing an upper half 101 and a lower half 102 of the inner cylinder, with the splice connected by a center-part flange 103. The support and positioning device includes support and positioning components that are respectively connected to the front and rear center-part flanges 103. The front support and positioning component includes a left support arm 201 and a right support arm 202 fixedly connected to the front center-part flange 103, and a shaft located between the left support arm 201 and the right support arm 202. The axial positioning block 3, the left support arm 201 and the right support arm 202 are symmetrically arranged on the left and right sides of the vertical centerline of the steam inlet 104 at the top of the low-pressure inner cylinder of the steam turbine. The axial positioning block 3 is fixedly connected to the front split flange 103 through multiple ribs 4. The axial positioning block 3 is clamped on the front outer cylinder bracket 5 and is used to axially position the low-pressure inner cylinder of the steam turbine. The left support arm 201 and the right support arm 202 are both placed on the front outer cylinder bracket 5. The rear support positioning assembly is symmetrically arranged with the front support positioning assembly.

[0032] By designing the axial positioning block 3 separately from the left support arm 201 and the right support arm 202, that is, by disconnecting and separating the left support arm 201 and the right support arm 202 from the axial positioning block 3, the rigidity of the split flange 103 is reduced. This ensures that the connection between the support positioning assembly and the split flange 103 has the least impact on the uniform and continuous thermal expansion of the high-temperature region of the low-pressure inner cylinder of the turbine, so that the thermal expansion of the high-temperature steam inlet region of the low-pressure inner cylinder of the turbine is uniform and continuous, and the occurrence of local stress concentration is reduced.

[0033] In Example 1, as Figure 1-3 As shown, a horizontal support plate 501 is provided at the rear of the front outer cylinder bracket 5. An outer cylinder axial positioning flange 502 is provided at the front center of the top of the support plate 501. A locking notch 301 with a shape and size that matches the outer cylinder axial positioning flange 502 is provided at the front center of the axial positioning block 3. The outer cylinder axial positioning flange 502 is locked in the locking notch 301. The left support arm 201 is placed at the left side of the top surface of the support plate 501, and the right support arm 202 is placed at the right side of the top surface of the support plate 501. In this way, by setting the outer cylinder axial positioning flange 502 in the locking notch 301 of the axial positioning block 3, the axial positioning function of the low-pressure inner cylinder of the steam turbine is achieved. Preferably, the right end face of the left support arm 201 is adjacent to the left side face of the axial positioning block 3, and the left end face of the right support arm 202 is adjacent to the right side face of the axial positioning block 3. The connection positions of the left support arm 201 and the right support arm 202 with the front center flange 103 are both located in the low temperature region of the turbine's low-pressure inner cylinder.

[0034] In Example 1, as Figure 1-3As shown, an L-shaped left pad 601 is fitted into the gap between the left side of the outer cylinder axial positioning flange 502 and the left side of the locking notch 301. The horizontal top plate of the left pad 601 is placed on the left side of the top surface of the axial positioning block 3 and is fixedly connected to the axial positioning block 3. An L-shaped right pad 602 is fitted into the gap between the right side of the outer cylinder axial positioning flange 502 and the right side of the locking notch 301. The horizontal top plate of the right pad 602 is placed on the right side of the top surface of the axial positioning block 3 and is fixedly connected to the axial positioning block 3. In this way, through the cooperation of the left pad 601 and the right pad 602, the connection between the axial positioning block 3 and the outer cylinder axial positioning flange 502 is more stable.

[0035] In Example 2, as Figure 5-8 As shown, an outer cylinder axial positioning flange 502 is provided at the rear middle of the front outer cylinder bracket 5, and a locking notch 301 with a shape and size that is compatible with the outer cylinder axial positioning flange 502 is provided at the front middle of the axial positioning block 3. The outer cylinder axial positioning flange 502 is locked in the locking notch 301. The left support arm 201 is placed at the left side of the front outer cylinder bracket 5, and the right support arm 202 is placed at the right side of the front outer cylinder bracket 5. The left support arm 201 and the right support arm 202 are arranged at a certain distance from the axial positioning block 3. The connection positions of the left support arm 201 and the right support arm 202 with the front center flange 103 are both located in the low temperature region of the turbine low-pressure inner cylinder.

[0036] In this invention, such as Figure 1-3 As shown in Figures 5-8, since the connection positions of the left support arm 201 and the right support arm 202 with the front center flange 103 are both located in the low-temperature region of the turbine's low-pressure inner cylinder, this optimizes the connection positions of the left support arm 201 and the right support arm 202 with the front center flange 103, avoiding the connection positions of the left support arm 201 and the right support arm 202 with the front center flange 103 located in the high-temperature steam inlet region of the turbine's low-pressure inner cylinder, thereby reducing the impact on the smooth, uniform, and continuous thermal expansion of the high-temperature region of the turbine's low-pressure inner cylinder.

[0037] In the embodiments of this patent, such as Figure 1-8As shown, the rear side of the axial positioning block 3 is fixedly connected to the front center flange 103 via two left and right ribs 4. The left and right ribs 4 are symmetrically arranged on the left and right sides relative to the vertical centerline of the steam inlet 104 at the top of the low-pressure inner cylinder of the turbine, with the left rib 4 inclined to the left rear side. In this way, the axial positioning block 3, the left rib 4, the right rib 4 and the center flange 103 are arranged in an isosceles trapezoidal shape. This ensures the rigidity of the axial positioning block 3 while minimizing the change in the radial rigidity of the low-pressure inner cylinder of the turbine. It also reduces the impact of the connection between the axial positioning block 3 and the center flange 103 on the uniformity and continuity of thermal expansion in the high-temperature area of ​​the low-pressure inner cylinder of the turbine. This makes the thermal expansion in the high-temperature steam inlet area of ​​the low-pressure inner cylinder of the turbine smooth, uniform and continuous, thereby reducing the occurrence of excessive local stress concentration.

[0038] In Embodiment 1, both the left support arm 201 and the right support arm 202 are welded to the center-part flange 103. In Embodiment 2, both the left support arm 201 and the right support arm 202 are integrally connected to the center-part flange 103. In the above embodiments, both the left rib plate 4 and the right rib plate 4 are welded to the front center-part flange 103.

[0039] The split-type support and positioning device of the present invention can be directly applied to the design of axial positioning of the low-pressure inner cylinder of a steam turbine, especially the high-temperature area of ​​the low-pressure inner cylinder of the steam turbine, which adopts a transverse support method. It can also be applied to the unit modification project where the inner cylinder is modified but the outer cylinder is not modified. It can also be applied to the design of units that use the same support and positioning method but have a high steam inlet temperature in the low-pressure inner cylinder of the steam turbine.

[0040] In summary, this turbine low-pressure inner cylinder support and positioning device uses a split design for the axial positioning block 3, the left support arm 201, and the right support arm 202 to reduce the stiffness of the center flange 103. This ensures that the connection between the support and positioning components and the center flange 103 has minimal impact on the thermal expansion barrier of the high-temperature region of the turbine low-pressure inner cylinder. Furthermore, the axial positioning block 3, the left rib plate 4, the right rib plate 4, and the center flange 103 are arranged in an isosceles trapezoidal shape. This ensures the stiffness of the axial positioning block 3 while minimizing changes in the radial stiffness of the turbine low-pressure inner cylinder. This reduces the impact of the connection between the axial positioning block 3 and the center flange 103 on the uniformity and continuity of thermal expansion in the high-temperature region of the turbine low-pressure inner cylinder, allowing for smooth, uniform, and continuous thermal expansion in the high-temperature steam inlet region of the turbine low-pressure inner cylinder, thereby reducing the occurrence of local stress concentrations.

[0041] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A split-type support and positioning device for a low-pressure inner cylinder of a steam turbine, wherein the low-pressure inner cylinder of the steam turbine is formed by splicing an upper half (101) and a lower half (102) of the inner cylinder, and the splice is connected by a center-split flange (103), characterized in that: The support positioning device includes a support positioning assembly connected to the front and rear split flanges (103) respectively. The front support positioning assembly includes a left support arm (201) and a right support arm (202) fixedly connected to the front split flange (103), and an axial positioning block (3) located between the left support arm (201) and the right support arm (202). The axial positioning block (3) is fixedly connected to the front split flange (103) through multiple ribs (4). The axial positioning block (3) is mounted on the front outer cylinder bracket (5). The left support arm (201) and the right support arm (202) are both placed on the front outer cylinder bracket (5). The left support arm (201) and the right support arm (202) are arranged symmetrically on the left and right sides relative to the vertical center line of the steam inlet (104) at the top of the low-pressure inner cylinder of the steam turbine. The rear support positioning component and the front support positioning component are arranged symmetrically front and back. The outer cylinder bracket (5) on the front side is provided with an outer cylinder axial positioning flange (502) at the rear. The axial positioning block (3) is provided with a locking notch (301) at the front middle part, which is adapted to the shape and size of the outer cylinder axial positioning flange (502). The outer cylinder axial positioning flange (502) is locked in the locking notch (301). The left support arm (201) is placed at the left side of the front outer cylinder bracket (5), and the right support arm (202) is placed at the right side of the front outer cylinder bracket (5). A horizontal support plate (501) is provided at the rear of the outer cylinder bracket (5) on the front side. The axial positioning flange (502) of the outer cylinder is located at the front center of the top of the support plate (501). The right end face of the left support arm (201) is close to the left side of the axial positioning block (3). The left end face of the right support arm (202) is close to the right side of the axial positioning block (3). The connection positions of the left support arm (201) and the right support arm (202) with the front center flange (103) are all located in the low temperature region of the low pressure inner cylinder of the steam turbine. The left support arm (201) is located at the left side of the top surface of the support plate (501), and the right support arm (202) is located at the right side of the top surface of the support plate (501).

2. The split-type support and positioning device for the low-pressure inner cylinder of a steam turbine according to claim 1, characterized in that: An L-shaped left pad (601) is fitted in the gap between the left side of the outer cylinder axial positioning flange (502) and the left side of the locking notch (301). The horizontal top plate of the left pad (601) is placed on the left side of the top surface of the axial positioning block (3) and is fixedly connected to the axial positioning block (3). An L-shaped right pad (602) is fitted in the gap between the right side of the outer cylinder axial positioning flange (502) and the right side of the locking notch (301). The horizontal top plate of the right pad (602) is placed on the right side of the top surface of the axial positioning block (3) and is fixedly connected to the axial positioning block (3).

3. The split-type support and positioning device for the low-pressure inner cylinder of a steam turbine according to claim 1, characterized in that: The left support arm (201) and the right support arm (202) are arranged at a certain distance from the axial positioning block (3).

4. The split-type support and positioning device for the low-pressure inner cylinder of a steam turbine according to claim 1, characterized in that: The rear side of the axial positioning block (3) is fixedly connected to the front split flange (103) through two left and right ribs (4). The left rib (4) and the right rib (4) are symmetrically arranged on the left and right sides relative to the vertical center line of the steam inlet (104) at the top of the low-pressure inner cylinder of the steam turbine. The left rib (4) is inclined to the left rear side.

5. The split-type support and positioning device for the low-pressure inner cylinder of a steam turbine according to claim 1, characterized in that: The left support arm (201) and the right support arm (202) are both welded to the center flange (103).

6. The split-type support and positioning device for the low-pressure inner cylinder of a steam turbine according to claim 1, characterized in that: The left support arm (201) and the right support arm (202) are both integrally connected to the center flange (103).

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