Steam turbine unit
The steam turbine unit addresses the issue of vibrations around the discharge port by employing a base plate and offset fixing members to enhance support rigidity, stabilizing the bearing sections and reducing vibrations.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- MITSUBISHI HEAVY INDUSTIES COMPRESSOR CORP
- Filing Date
- 2024-12-26
- Publication Date
- 2026-07-08
AI Technical Summary
The challenge in steam turbines is to improve support rigidity and suppress vibrations around the discharge port, particularly as rotor speed increases, due to the relatively low strength in the area surrounding the discharge port.
A steam turbine unit design with a base plate and fixing members positioned to offset in the axial direction, supporting the bearing portions and securely fixing the turbine to the foundation, enhancing support rigidity and reducing vibrations.
The design effectively suppresses vibrations around the discharge port by ensuring stable support and high rigidity, preventing deformation and tilt, thereby stabilizing the bearing sections and reducing vibrations.
Smart Images
Figure 2026114016000001_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to a steam turbine unit.
Background Art
[0002] A steam turbine includes a rotor disposed in a casing, a row of moving blades disposed radially outside the rotor, and a row of stationary blades disposed radially inside the casing. Such a steam turbine is fixed on a foundation via a base plate called a pedestal as described in Patent Document 1.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] By the way, in the above-described steam turbine, in order to improve efficiency, the demand for increasing the speed of the rotor is increasing. In order to increase the speed, it is necessary to stably support the steam turbine with respect to the foundation. Therefore, it is desired to improve the support rigidity by the base plate disposed between the steam turbine and the foundation. In particular, in a steam turbine, since the strength around a large opening and the discharge port formed is relatively low, an improvement in support rigidity for suppressing vibration around the discharge port is desired for the base plate.
[0005] The present disclosure has been made to solve the above problems, and an object thereof is to provide a steam turbine unit capable of suppressing vibration around a discharge port.
Means for Solving the Problems
[0006] To solve the above problems, the steam turbine unit according to the present disclosure comprises a steam turbine having a rotor extending in the axial direction on which a central axis extends, a casing covering the rotor from the radially outer side with respect to the central axis, and a bearing portion fixed to the casing and supporting the rotor so as to be rotatable relative to the casing; a base plate supporting the steam turbine from below in the vertical direction and fixed on a foundation; and a plurality of fixing members arranged apart from each other and capable of fixing the base plate and the foundation, wherein the casing has an outlet facing downward in the vertical direction and capable of discharging steam to the outside, the bearing portion has a downstream bearing portion positioned close to the outlet in the axial direction, the base plate supports the downstream bearing portion, and the plurality of fixing members are positioned so that the two fixing members closest to the region on the base plate that supports the downstream bearing portion are offset in the axial direction in the width direction perpendicular to the vertical and axial directions. [Effects of the Invention]
[0007] According to the steam turbine unit of this disclosure, vibrations can be suppressed around the exhaust port. [Brief explanation of the drawing]
[0008] [Figure 1] This is a schematic diagram of a steam turbine unit according to an embodiment of the present disclosure, viewed from the width direction. [Figure 2] This is a schematic diagram showing the base plate of a steam turbine unit viewed from a diagonal downward angle. [Figure 3] This is a schematic diagram showing the arrangement of multiple fixing members on the base plate when viewed from below in the vertical direction. [Modes for carrying out the invention]
[0009] The following describes embodiments for implementing the steam turbine unit according to the present invention with reference to the attached drawings. However, the present invention is not limited to these embodiments.
[0010] (Configuration of the steam turbine unit) As shown in Figure 1, the steam turbine unit 1 is fixed on a foundation 100. The foundation 100 is made of, for example, reinforced concrete. In this embodiment, the steam turbine unit 1 comprises a steam turbine 3 and a base plate 8.
[0011] (Steam turbine configuration) The steam turbine 3 comprises a rotor 2, a casing 5, stationary blades 6, and a bearing section 7.
[0012] (Rotor configuration) The rotor 2 extends in the axial direction Da. The rotor 2 extends through the interior of the casing 5 along the central axis O. The rotor 2 comprises a rotating shaft 21 and rotor blades 22.
[0013] In this embodiment, the direction in which the central axis O extends is defined as the axial direction Da. The axial direction Da of the rotor 2 lies along the horizontal plane. That is, the central axis O extends horizontally. In the steam turbine 3, the position where one end is located in the axial direction Da is referred to as the first side Da1. In the steam turbine 3, the position where the end opposite to the end of the first side Da1 is located in the axial direction Da is referred to as the second side Da2, which is on the opposite side of the axial direction Da from the first side Da1. The radial direction Dr of the rotor 2 with respect to the central axis O is simply referred to as the radial direction Dr. The radial direction Dr is perpendicular to the central axis O and partially coincides with the vertical direction Dv.
[0014] The rotating shaft 21 is formed in a cylindrical shape, extending in the axial direction Da with respect to its center. The rotating shaft 21 is supported by the casing 5 by the bearing portion 7 so as to be rotatable around the central axis O. The rotor blades 22 are arranged in multiple stages with spacing in the axial direction Da. Each rotor blade 22 is fixed so as to extend outward from the outer circumferential surface of the rotating shaft 21 in the radial direction Dr.
[0015] (Casing configuration) The casing 5 is formed to cover the rotor 2 from the outside in the radial direction Dr. Inside the casing 5, a main passage 55 through which high-pressure steam flows is formed. In the main passage 55, the steam flows from the first side Da1 to the second side Da2 in the axial direction Da. In the main passage 55, high-pressure steam flows from the upstream side to the downstream side, with the pressure gradually decreasing. The main passage 55 is formed in an annular shape around the rotation axis 21. Part of the main passage 55 is formed by an annular space in which a plurality of rotor blades 22 and stator blades 6 are arranged. Furthermore, the casing 5 of this embodiment has a casing body 50, an inlet 51, an outlet 52, and an extraction outlet 53.
[0016] The casing body 50 is formed in a cylindrical shape extending in the axial direction Da with respect to the central axis O. A circulating channel is formed inside the casing body 50. The casing body 50 is designed to be separable into upper and lower parts in the vertical direction Dv, with the horizontal plane passing through the central axis O serving as the dividing plane.
[0017] The suction port 51 is capable of supplying steam to the inside of the casing 5. High-temperature steam generated by a boiler (not shown) is supplied to the suction port 51. The high-temperature steam supplied to the suction port 51 is supplied to the main flow path 55 inside the casing body 50. In other words, the suction port 51 is connected to the uppermost part of the main flow path 55 (the firstmost Da1 in the axial direction Da). The suction port 51 is connected to the first side Da1 in the axial direction Da relative to the casing body 50. The suction port 51 opens to communicate the inside and outside of the casing body 50. The suction port 51 extends outward from the casing body 50 in the radial direction Dr. In this embodiment, the suction port 51 is formed in a cylindrical shape that extends upward in the vertical direction Dv relative to the casing body 50.
[0018] The discharge port 52 is capable of discharging steam to the outside of the casing 5. The discharge port 52 discharges the steam flowing from the main flow path 55. That is, the discharge port 52 is connected to the most downstream side (the second side Da2 in the axial direction Da) of the main flow path 55. The discharge port 52 is connected to the second side Da2 in the axial direction Da with respect to the casing body 50. The discharge port 52 is arranged at a distance from the suction port 51 on the second side Da2 in the axial direction Da. The discharge port 52 is open so as to communicate the inside and the outside of the casing body 50. The discharge port 52 is formed as an opening larger than the suction port 51 and the extraction discharge port 53. The discharge port 52 extends radially outward from the casing body 50. The discharge port 52 of the present embodiment faces downward in the vertical direction Dv with respect to the casing body 50.
[0019] The extraction discharge port 53 allows steam to flow inside and outside the casing 5. The steam passing through the extraction discharge port 53 and the main flow path 55 can be discharged to the outside of the casing 5. The extraction discharge port 53 is connected to the casing body 50. The extraction discharge port 53 extends radially outward from the casing body 50. The extraction discharge port 53 of the present embodiment faces downward in the vertical direction Dv with respect to the casing body 50. The extraction discharge port 53 is arranged between the suction port 51 and the discharge port 52 in the axial direction Da. The extraction discharge port 53 is arranged at a distance from the suction port 51 and the discharge port 52 in the axial direction Da.
[0020] (Configuration of the stationary blades) The plurality of stationary blades 6 are fixed inside the casing 5 in the radial direction Dr. The plurality of stationary blades 6 form a row arranged in a tubular shape. The plurality of stationary blades 6 are fixed to the casing 5 such that the rows are arranged at intervals in the axial direction Da. The stationary blades 6 are arranged side by side on the upstream side with respect to the corresponding moving blades 22 to form a stage.
[0021] (Configuration of the bearing portion) The bearing portion 7 is fixed to the casing 5 and supports the rotor 2 so as to be rotatable with respect to the casing 5. The bearing portion 7 is dividable vertically in the vertical direction Dv such that a horizontal plane passing through the central axis O is a dividing surface. The bearing portion 7 of the present embodiment includes a front-stage bearing portion 71 and a rear-stage bearing portion 72.
[0022] The front-stage bearing portion 71 rotatably supports the end portion of the rotating shaft 21 on the first side Da1 in the axial direction Da. The front-stage bearing portion 71 is disposed at a position close to the suction port 51 in the axial direction Da. The front-stage bearing portion 71 is disposed on the first side Da1 in the axial direction Da with respect to the suction port 51. The front-stage bearing portion 71 is disposed apart from the rear-stage bearing portion 72 in the axial direction Da so as to sandwich the discharge port 52 therebetween in the axial direction Da. The front-stage bearing portion 71 has, for example, a journal bearing and a thrust bearing. The front-stage bearing portion 71 is fixed to the casing main body 50 on the first side Da1 in the axial direction Da with respect to the casing main body 50.
[0023] The rear-stage bearing portion 72 rotatably supports the end portion of the rotating shaft 21 on the second side Da2 in the axial direction Da. The rear-stage bearing portion 72 is disposed at a position close to the discharge port 52 in the axial direction Da. The rear-stage bearing portion 72 is disposed on the second side Da2 in the axial direction Da with respect to the discharge port 52. The rear-stage bearing portion 72 is disposed apart from the front-stage bearing portion 71 in the second side Da2 in the axial direction Da so as to sandwich the casing main body 50 therebetween in the axial direction Da. The rear-stage bearing portion 72 has, for example, a journal bearing. The rear-stage bearing portion 72 is fixed to the casing main body 50 on the second side Da2 in the axial direction Da with respect to the casing main body 50.
[0024] (Configuration of the base plate) The base plate 8 supports the steam turbine 3 from below in the vertical direction Dv. The base plate 8 is fixed on the foundation 100. The base plate 8 is also fixed to the steam turbine 3. For example, the base plate 8 is fixed to the steam turbine 3 in a manner that allows movement in the axial direction Da. On the other hand, the base plate 8 is fixed to the foundation 100 in an immovable manner by the fixing member 9. The base plate 8 supports the bearing section 7 from below in the vertical direction Dv. The base plate 8 is fixed to the front bearing section 71 and the rear bearing section 72. As shown in Figures 2 and 3, the base plate 8 of this embodiment has a front support section 81, a rear support section 82, and an axial beam section 83.
[0025] The front support section 81 supports the front bearing section 71 from below in the vertical direction Dv. The front support section 81 is a columnar member extending in the axial direction Da and in the width direction Dw, which is perpendicular to the vertical direction Dv. The front support section 81 is, for example, an H-beam. The front support section 81 is positioned so as to overlap with the front bearing section 71 when viewed from the vertical direction Dv. The front support section 81 is positioned so as to be away from (not overlapping with) the discharge port 52 and the extraction discharge port 53 when viewed from the vertical direction Dv.
[0026] The rear support section 82 supports the rear bearing section 72 from below in the vertical direction Dv. The rear support section 82 is a columnar member extending in the width direction Dw. The rear support section 82 is, for example, an H-beam. When viewed from the width direction Dw, the rear support section 82 is positioned alongside the discharge port 52. When viewed from the vertical direction Dv, the rear support section 82 is positioned to overlap with the rear bearing section 72. When viewed from the vertical direction Dv, the rear support section 82 is positioned away from (not overlapping with) the suction port 51, discharge port 52, and extraction discharge port 53. The rear support section 82 is positioned away from the front support section 81 on the second side Da2 in the axial direction Da. When viewed from the axial direction Da, the rear support section 82 is positioned to overlap with the discharge port 52.
[0027] The axial beam section 83 extends in the axial direction Da and connects the front support section 81 and the rear support section 82. The axial beam section 83 is a columnar member extending in the axial direction Da. The axial beam section 83 is, for example, an H-beam. The axial beam sections 83 are arranged in pairs, separated in the width direction Dw. When viewed from the vertical direction Dv, the axial beam sections 83 are positioned away from the intake port 51, the discharge port 52, and the extraction discharge port 53 (in a position where they do not overlap).
[0028] As a result, when viewed from the vertical direction Dv, the base plate 8 forms an opening 85 surrounded by a pair of axial beam sections 83, a front support section 81, and a rear support section 82. In other words, the base plate 8 is formed as a hollow rectangular annular frame by the pair of axial beam sections 83, the front support section 81, and the rear support section 82. The discharge port 52 is positioned to be inserted through the opening 85. That is, the discharge port 52 is positioned in the opening 85 so as to be able to communicate with the base plate 8 downwards in the vertical direction Dv. Therefore, when viewed from the width direction Dw, the discharge port 52 and the extraction discharge port 53 are positioned to penetrate the base plate 8 in the vertical direction Dv. Therefore, the discharge port 52 and the extraction discharge port 53 are connected to the outside of the steam turbine 3 system through recesses and openings (not shown) formed in the foundation 100.
[0029] (Configuration of fixing members) Multiple fixing members 9 are capable of fixing the base plate 8 and the foundation 100. The fixing members 9 are, for example, bolts. The multiple fixing members 9 are arranged apart from each other. The multiple fixing members 9 are arranged offset in the width direction Dw and the axial direction Da in at least some areas. In the case of the multiple fixing members 9, the two fixing members 9 closest to the area supporting the rear bearing portion 72 on the base plate 8 are positioned offset in the axial direction Da in the width direction Dw. When viewed from the width direction Dw, the multiple fixing members 9 are arranged offset in the axial direction Da in at least the area overlapping with the rear bearing portion 72. The multiple fixing members 9 of this embodiment include multiple front fixing members 91, multiple rear fixing members 92, and multiple beam fixing members 93.
[0030] Multiple front-stage fixing members 91 are fixed to the front-stage support 81 and the foundation 100. When viewed from the vertical direction Dv, the multiple front-stage fixing members 91 are positioned far apart from each other, close to the four corners of the front-stage bearing 71. Therefore, in this embodiment, four front-stage fixing members 91 are positioned far apart in the axial direction Da and the width direction Dw. Furthermore, when viewed from the vertical direction Dv, the multiple front-stage fixing members 91 are positioned off-center from the central axis O.
[0031] Multiple rear fixing members 92 are fixed to the rear support section 82 and the foundation 100. The multiple rear fixing members 92 are arranged apart from each other in the width direction Dw. When viewed from the vertical direction Dv, the multiple rear fixing members 92 are arranged symmetrically with respect to the central axis O. In the region of the rear support section 82 on one side in the width direction Dw with respect to the central axis O, the two closest rear fixing members 92 in the width direction Dw are offset in the axial direction Da. Therefore, in the region of the rear support section 82 on one side in the width direction Dw with respect to the central axis O, when viewed from the vertical direction Dv, adjacent rear fixing members 92 are arranged in a staggered pattern so as to be alternating. In this embodiment, only the multiple rear fixing members 92 are arranged in a staggered pattern with their positions offset in the width direction Dw and axial direction Da while being separated from each other. The multiple downstream fixing members 92 are arranged in alternating positions in a region on one side of the width direction Dw with respect to the central axis O of the downstream support portion 82, with three or more (four in this embodiment) being positioned. Therefore, eight downstream fixing members 92 are arranged for one downstream support portion 82. Furthermore, the multiple downstream fixing members 92 are positioned off-center from the central axis O when viewed from the vertical direction Dv. The multiple downstream fixing members 92 are positioned to overlap with the discharge port 52 when viewed from the axial direction Da.
[0032] Multiple beam fixing members 93 fix the axial beam section 83 to the foundation 100. Multiple beam fixing members 93 are arranged on each of the pair of axial beam sections 83. When viewed from the vertical direction Dv, multiple beam fixing members 93 are arranged (for example, seven) spaced apart from each other in the axial direction Da for one axial beam section 83. In this embodiment, the multiple beam fixing members 93 are arranged in a straight line in the axial direction Da.
[0033] (Effects and Benefits) In the steam turbine 3 of the steam turbine 3 system with the above configuration, a large outlet 52 is formed so as to communicate with the inside and outside of the casing body 50. Therefore, in the steam turbine 3, the area around the outlet 52 is formed as a large opening, and tends to have relatively lower strength compared to other parts of the casing 5. When the rotor 2 is increased in speed in such a steam turbine 3, a deformation mode occurs near the outlet 52 that causes it to tilt in the vertical direction Dv and axial direction Da due to vibration. Furthermore, this deformation mode also affects the downstream bearing section 72 which is located close to the outlet 52. In particular, in this embodiment, since the outlet 52 faces downward in the vertical direction Dv, the outlet 52 is located close to the fixing part between the base plate 8 and the foundation 100 in the vertical direction Dv. Therefore, vibrations from the outlet 52 are easily transmitted to the base plate 8, and the deformation that occurs in the base plate 8 becomes larger.
[0034] However, in this embodiment, the base plate 8 supporting the downstream bearing section 72 is fixed to the foundation 100 by a plurality of fixing members 9. Furthermore, when viewed from the width direction Dw, the two fixing members 9 closest to each other in the region supporting the downstream bearing section 72 are positioned offset in the axial direction Da. In other words, the two fixing members 9 separated in the width direction Dw are positioned relative to the base plate 8 and the foundation 100 in such a way that they form a virtual plane (line) inclined with respect to the axial direction Da by fixing the base plate 8 and the foundation 100 at positions offset in the axial direction Da. Therefore, the two fixing members 9 separated in the width direction Dw work to suppress deformation modes that would cause the downstream support section 82 located near the discharge port 52 to tilt in the vertical direction Dv and axial direction Da. Consequently, the base plate 8 is firmly fixed to the foundation 100 around the discharge port 52, and support rigidity that suppresses vibration can be ensured in the base plate 8. This suppresses vibrations in the downstream bearing section 72 supported by the base plate 8, thereby reducing vibrations around the discharge port 52.
[0035] Furthermore, the rear support portion 82, which supports the rear bearing portion 72, and the base 100 are fixed together by multiple rear fixing members 92 when viewed from the axial direction Da. As a result, the deformation of the rear support portion 82 that supports the rear bearing portion 72 can be directly suppressed at a close position by the multiple rear fixing members 92. Consequently, vibration of the rear bearing portion 72 can be stably suppressed at a position close to the discharge port 52 in the vertical direction Dv. This also suppresses vibration of the rear bearing portion 72 supported by the base plate 8, and vibration can be stably suppressed around the discharge port 52.
[0036] Furthermore, three or more of the downstream fixing members 92 are arranged in an alternating pattern. As a result, the multiple downstream fixing members 92 are arranged relative to the base plate 8 and the foundation 100 so as to form multiple virtual planes (lines) inclined in different directions with respect to the axial direction Da. Therefore, the three or more downstream fixing members 92 work to suppress deformation modes that cause the downstream support portion 82 located near the discharge port 52 to tilt in the vertical direction Dv and axial direction Da. Consequently, the base plate 8 is more firmly fixed to the foundation 100 around the discharge port 52, and high support rigidity that suppresses vibration can be ensured in the base plate 8. As a result, vibration of the downstream bearing portion 72 supported by the base plate 8 is also further suppressed, and vibration can be further suppressed around the discharge port 52.
[0037] Furthermore, in addition to the rear support portion 82, the base plate 8 has a front support portion 81 that supports the front bearing portion 71, and a pair of axial beam portions 83 that connect the front support portion 81 and the rear support portion 82. Moreover, when viewed from the vertical direction Dv, an opening 85 is formed in the base plate 8 by the pair of axial beam portions 83, the front support portion 81, and the rear support portion 82. The discharge port 52 and the extraction discharge port 53 are positioned to be inserted through this opening 85. The rigidity of the base plate 8 with such an opening 85 is significantly lower than that of a base plate 8 without an opening 85, making the base plate 8 susceptible to deformation. However, in this embodiment, the rear support portion 82 and the foundation 100 are fixed by a plurality of rear fixing members 92. Therefore, the influence of the overall rigidity of the base plate 8 is suppressed, and high support rigidity that suppresses vibration can be secured around the discharge port 52 of the base plate 8. This also suppresses vibrations in the downstream bearing section 72 supported by the base plate 8, allowing for more stable vibration suppression around the discharge port 52.
[0038] (Other embodiments) Although embodiments of this disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and may include design changes and the like that do not depart from the gist of this disclosure.
[0039] In this embodiment, the steam turbine 3 had an extraction outlet 53, but it is not limited to this structure. Therefore, the steam turbine 3 does not have to have an extraction outlet 53. Also, the steam turbine 3 may have an extraction inlet that allows new steam to be supplied from outside the casing 5 to the steam passing through the main flow path 55.
[0040] Furthermore, in this embodiment, among the multiple fixing members 9, only the rear fixing members 92 located in a portion of the rear support portion 82 (the region on one side of the width direction Dw with respect to the central axis O of the rear support portion 82) are arranged in a staggered pattern so as to be alternating. However, the arrangement of the multiple fixing members 9 is not limited to this structure. For example, the rear fixing members 92 located in all areas of the rear support portion 82 may be arranged in a staggered pattern so as to be alternating. Moreover, not only the rear fixing members 92, but also the front fixing members 91 and the beam fixing members 93 may be arranged in a staggered pattern so as to be alternating.
[0041] Furthermore, although the base plate 8 had an opening 85 in this embodiment, it is not limited to this shape. Therefore, the base plate 8 may have a shape that does not have an opening 85.
[0042] <Note> The steam turbine unit 1 described in the embodiment can be understood, for example, as follows:
[0043] (1) The steam turbine unit 1 according to the first embodiment includes a rotor 2 extending in the axial direction Da of the central axis O, a casing 5 covering the rotor 2 from the outside in the radial direction Dr with respect to the central axis O, and a bearing portion 7 fixed to the casing 5 and supporting the rotor 2 so as to be rotatable relative to the casing 5, a base plate 8 supporting the steam turbine 3 from below in the vertical direction Dv and fixed on a foundation 100, and a plurality of fixing portions arranged apart from each other and capable of fixing the base plate 8 and the foundation 100. The casing 5 comprises a material 9 and a bearing portion 7, the bearing portion 7 having a discharge port 52 facing downward in the vertical direction Dv and capable of discharging steam to the outside, the bearing portion 7 having a rear bearing portion 72 positioned close to the discharge port 52 in the axial direction Da, the base plate 8 supporting the rear bearing portion 72, and the plurality of fixing members 9, in relation to the region of the base plate 8 that supports the rear bearing portion 72, the two fixing members 9 closest to each other in the width direction Dw perpendicular to the vertical direction Dv and the axial direction Da are positioned offset in the axial direction Da.
[0044] With this configuration, the two fixing members 9, separated in the width direction Dw, are positioned relative to the base plate 8 and foundation 100 so as to form a virtual plane (line) inclined with respect to the axial direction Da, by fixing the base plate 8 and foundation 100 at positions offset in the axial direction Da. Therefore, the two fixing members 9, separated in the width direction Dw, work to suppress deformation modes that cause the base plate 8, located near the discharge port 52, to tilt in the vertical direction Dv and axial direction Da. Consequently, the base plate 8 is firmly fixed to the foundation 100 around the discharge port 52, and support rigidity that suppresses vibration can be ensured in the base plate 8. As a result, vibration of the downstream bearing section 72 supported by the base plate 8 is also suppressed, and vibration can be suppressed around the discharge port 52.
[0045] (2) The steam turbine unit 1 according to the second embodiment is the steam turbine unit 1 of (1), wherein the base plate 8 has a rear support portion 82 that supports the rear bearing portion 72 from below in the vertical direction Dv and is arranged alongside the discharge port 52 when viewed from the width direction Dw, and the plurality of fixing members 9 have a rear fixing member 92 that is arranged in a position that overlaps with the discharge port 52 when viewed from the axial direction Da and fixes the rear support portion 82 and the base 100.
[0046] With this configuration, the deformation of the rear support portion 82 that supports the rear bearing portion 72 can be directly suppressed at a close position by the multiple rear fixing members 92. Therefore, vibration of the rear bearing portion 72 can be stably suppressed at a position close to the discharge port 52 in the vertical direction Dv. As a result, vibration of the rear bearing portion 72 supported by the base plate 8 is also suppressed, and vibration can be stably suppressed around the discharge port 52.
[0047] (3) The steam turbine unit 1 according to the third embodiment is the steam turbine unit 1 of (2), wherein the plurality of downstream fixing members 92 are arranged in three or more in an alternating manner.
[0048] With this configuration, the multiple downstream fixing members 92 are arranged relative to the base plate 8 and the foundation 100 so as to form multiple virtual planes (lines) inclined in different directions with respect to the axial direction Da. As a result, three or more downstream fixing members 92 work to suppress deformation modes that cause the downstream support portion 82 located near the discharge port 52 to tilt in the vertical direction Dv and axial direction Da. Consequently, the base plate 8 is more firmly fixed to the foundation 100 around the discharge port 52, and high support rigidity that suppresses vibration can be ensured in the base plate 8. This further suppresses vibration of the downstream bearing portion 72 supported by the base plate 8, and vibration can be further suppressed around the discharge port 52.
[0049] (4) A steam turbine unit 1 according to the fourth embodiment is the steam turbine unit 1 of (2) or (3), wherein the casing 5 has an intake port 51 that allows steam to flow into the interior at a position away from the outlet port 52 in the axial direction Da, and the bearing portion 7 has a front bearing portion 71 that is positioned away from the rear bearing portion 72 in the axial direction Da such that the outlet port 52 is sandwiched between the rear bearing portion 72 and the front bearing portion 71 in the axial direction Da. The base plate 8 has a front support portion 81 that supports the front bearing portion 71 from below in the vertical direction Dv, and a pair of axial beam portions 83 that extend in the axial direction Da and connect the front support portion 81 and the rear support portion 82. When viewed from the vertical direction Dv, the base plate 8 forms an opening 85 surrounded by the pair of axial beam portions 83, the front support portion 81, and the rear support portion 82, and the discharge port 52 is positioned to be inserted through the opening 85.
[0050] With this configuration, the influence of the overall rigidity of the base plate 8 can be minimized, and high support rigidity that suppresses vibration can be secured around the discharge port 52 of the base plate 8. As a result, vibration of the downstream bearing section 72 supported by the base plate 8 is also suppressed, and vibration can be suppressed more stably around the discharge port 52. [Explanation of Symbols]
[0051] 1. Steam Turbine Unit 100 Basics 3 Steam Turbine O center axis 2 rotors 21 Rotation axis 22 Moving blade 5. Casing 55 Main channel 50 Casing body 51 Inlet 52 Outlet 53 Bleed air outlet 6 Static Wings 7 Bearing section 71 Front bearing section 72 Rear bearing section 8 base plates 81 Front stage support section 82 Rear support section 83 Axial beam section 85 Opening 9 Fixing member 91 Front fixing member 92 Rear fixing member 93 Beam fixing member Da axis direction Da1 first side Da2 second side Dr radial direction Dv Vertical direction Dw width direction
Claims
1. A steam turbine having a rotor extending in the axial direction over which a central axis extends, a casing covering the rotor from the radially outer side with respect to the central axis, and a bearing portion fixed to the casing and supporting the rotor so as to be rotatable relative to the casing, The steam turbine is supported from below in the vertical direction by a base plate fixed on a foundation, It comprises a plurality of fixing members that are arranged apart from each other and capable of fixing the base plate and the foundation, The casing has an outlet facing downward in the vertical direction, from which steam can be discharged to the outside. The bearing portion has a downstream bearing portion positioned in the axial direction close to the discharge port, The base plate supports the rear bearing section, In a steam turbine unit, the two fixing members closest to the region supporting the rear bearing portion on the base plate are positioned offset in the axial direction, with respect to the width direction perpendicular to the vertical and axial directions.
2. The base plate has a rear support portion that supports the rear bearing portion from below in the vertical direction and is arranged alongside the discharge port when viewed from the width direction. The steam turbine unit according to claim 1, wherein the plurality of fixing members are positioned to overlap with the discharge port when viewed from the axial direction, and the rear fixing member fixes the rear support portion and the foundation.
3. The steam turbine unit according to claim 2, wherein three or more of the aforementioned downstream fixing members are arranged in an alternating manner.
4. The casing has a suction port located at a position axially separated from the outlet, which allows the steam to flow into the interior. The bearing portion has a front bearing portion that is positioned axially away from the rear bearing portion so as to sandwich the discharge port between them in the axial direction. The aforementioned base plate is A front support portion that supports the aforementioned front bearing portion from below in the vertical direction, It has a pair of axial beam sections that extend in the axial direction and connect the front support section and the rear support section, The base plate, when viewed from the vertical direction, forms an opening surrounded by a pair of axial beam sections, a front support section, and a rear support section. The steam turbine unit according to claim 2 or 3, wherein the discharge port is positioned in a state where it is inserted into the opening.