Steam turbine system

Abstract

To provide a steam turbine system that, even when a steam leak occurs, can discharge the steam to the outside.SOLUTION: A steam turbine system comprises: a main steam stop valve having a first valve element capable of moving forward and backward along a first axial line, a first valve seat capable of abutting against the first valve element, and a first casing forming a first space that accommodates the first valve element and the first valve seat; and a steam control valve having a second valve element capable of moving forward and backward along a second axial line, a second valve seat having a second seat surface capable of abutting against the second valve element, and a second casing forming a second space that accommodates the second valve element and the second valve seat. A ventilator flow path, which communicates with an external condenser, is provided in a connection flow path between the main steam stop valve and the steam control valve. The steam turbine system further comprises a solenoid valve provided between the ventilator flow path and the condenser, and a control device the controls open and close states of the solenoid valve. The control device brings the solenoid valve into the open state in the case where the main steam stop valve is in a close state and the interior of the condenser is in a vacuum state.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to steam turbine systems. [Background technology]

[0002] Steam turbine plants are equipped with a main steam stop valve (on / off valve) that switches the steam supply to the turbine, and a steam control valve that precisely controls the steam flow rate (see Patent Document 1 below). Viewed from the direction of steam flow, the main steam stop valve is located upstream, and the steam control valve is located immediately downstream and integrated with it. When shutting down the turbine, both of these valves are closed to prevent steam from flowing into the turbine. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-43591 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the case of a main steam stop valve, misalignment can occur between the valve disc and the valve seat, preventing it from closing completely. This causes steam to flow in through the gap between the valve disc and the valve seat, and then into the turbine through minute gaps formed in various places in the downstream steam control valve, creating a problem.

[0005] The present disclosure has been made to solve the above-mentioned problem, and aims to provide a steam turbine system that, even if steam leakage occurs, can discharge the steam to the outside without allowing it to flow into the turbine. [Means for solving the problem]

[0006] In order to solve the above problem, a steam turbine system according to the present disclosure includes a main steam stop valve having a first valve disc movable back and forth along a first axis, a first valve seat capable of abutting against the first valve disc, and a first casing forming a first space accommodating the first valve disc and the first valve seat; a steam control valve having a second valve disc movable back and forth along a second axis, a second valve seat having a second seat surface capable of abutting against the second valve disc, and a second casing forming a second space accommodating the second valve disc and the second valve seat; and a connecting flow path connecting the main steam stop valve and the steam control valve, wherein a ventilator flow path communicating with an external condenser is formed in the connecting flow path, and the steam turbine system further includes a solenoid valve provided between the ventilator flow path and the condenser, and a control device that controls the opening and closing state of the solenoid valve, wherein the control device opens the solenoid valve when the main steam stop valve is closed and the condenser is in a vacuum state. [Effects of the Invention]

[0007] According to the present disclosure, a steam turbine system can be provided that reliably applies a differential pressure across the main steam stop valve to maintain the valve closed, and that, in the unlikely event of a steam leak, can discharge the steam to the outside without allowing it to flow into the turbine. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram illustrating a portion of a steam turbine system according to an embodiment of the present disclosure. [Figure 2] FIG. 1 is a cross-sectional view showing a configuration of a valve device according to an embodiment of the present disclosure. [Figure 3] FIG. 2 is an enlarged cross-sectional view of a main portion of a valve device according to an embodiment of the present disclosure. [Figure 4] FIG. 2 is a functional block diagram of a control device according to an embodiment of the present disclosure. [Figure 5] 4 is a flowchart illustrating processing by a control device according to an embodiment of the present disclosure. [Figure 6] 10 is a flowchart illustrating a first modified example of the processing of the control device according to the embodiment of the present disclosure. [Figure 7]10 is a flowchart illustrating a second modified example of the processing of the control device according to the embodiment of the present disclosure. [Figure 8] FIG. 1 is a hardware configuration diagram of a computer according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a valve gear 10 according to a first embodiment of the present disclosure and a steam turbine system 1 including the valve gear will be described with reference to FIGS. 1 to 5. FIG.

[0010] (Configuration of steam turbine system 1) As shown in FIG. 1, the steam turbine system 1 includes a plurality of (for example, two) valve devices 10, a recovery flow path 11, a check valve 12, a solenoid valve 13, a condenser 14, a control device 15, and a ventilator flow path 16.

[0011] As will be described in more detail later, the valve device 10 is provided to control the amount of steam supplied to a turbine (not shown). The valve device 10 is provided with a ventilator flow path 16 for releasing steam (referred to as leakage steam) that has passed through the valve device 10 when the turbine is stopped toward a condenser 14. A check valve 12 is provided on each ventilator flow path 16. This check valve 12 is provided so that when leakage steam flows out of one valve device 10, the leakage steam does not flow back through the ventilator flow path 16 toward another valve device 10.

[0012] The downstream end of the ventilator flow path 16 is connected to the recovery flow path 11. The downstream end of the recovery flow path 11 is connected to the condenser 14. The condenser 14 is a device that converts low-temperature steam that has completed its work in the turbine, which uses steam supplied from the valve device 10, back into water and sends it back to the boiler. While the turbine is in operation, the inside of the condenser 14 is kept in a vacuum state. Therefore, leakage steam flowing through the recovery flow path 11 flows toward the condenser 14 due to the pressure difference. By being sent to the condenser 14, the leakage steam is converted back into water, just like steam recovered from other paths, and is eventually sent to the boiler. Although not shown in detail, the condenser 14 is equipped with a pressure sensor or pressure gauge that detects the internal pressure state. Information about this pressure is sent as an electrical signal to the control device 15, which will be described later.

[0013] A solenoid valve 13 is provided on the recovery flow path 11. The solenoid valve 13 is provided to switch the open state of the recovery flow path 11 and the ventilator flow path 16. The open / close state of the solenoid valve 13 is controlled by a control device 15. The configuration and processing flow of the control device 15 will be described later.

[0014] (Configuration of valve device 10) Next, the configuration of the valve gear 10 will be described in detail with reference to Figures 2 and 3. As shown in Figure 2, this valve gear 10 includes a main steam stop valve 2 and a steam control valve 3. The main steam stop valve 2 is an on-off valve that switches between supplying and stopping steam. The steam control valve 3 is an adjustment valve that more precisely controls the flow rate of steam supplied to the turbine when the main steam stop valve 2 is in the open state.

[0015] (Configuration of main steam stop valve 2) The main steam stop valve 2 has a first casing 21, a first valve stem 22, a first drive unit 23, a bush 24, a first valve body 25, a first valve seat 26, a physical quantity acquisition unit 27, and a first opening / closing sensor 28.

[0016] The first valve stem 22, the first valve body 25, and the first valve seat 26 are housed in a first space 90 in the first casing 21. This first space 90 is a space for the first valve stem 22 and the first valve body 25 to move back and forth, and also a flow path for steam to flow. A supply flow path 91 that communicates with the boiler is connected to the first space 90. Steam flows into the first space 90 through the supply flow path 91.

[0017] The first valve stem 22 is rod-shaped and extends along the horizontal first axis X. The horizontal direction here refers to the substantially horizontal direction, and slight deviations are permitted. The first valve stem 22 is supported within the first casing 21 via a bushing 24 provided between the first casing 21 and the bushing 24. The bushing 24 is cylindrical and centered on the first axis X, with the first valve stem 22 inserted therethrough. The bushing 24 has a large-diameter portion 41 and a small-diameter portion 42. The large-diameter portion 41 and the small-diameter portion 42 are integrally formed, with the large-diameter portion 41 located on one side of the small-diameter portion 42 in the direction of the first axis X. The large-diameter portion 41 engages with a stepped portion 92 of the first casing 21 from one side in the direction of the first axis X. A coil spring (not shown) is disposed on the end face of the small-diameter portion 42 on the other side in the direction of the first axis X. The biasing force of this coil spring is received by the bushing 24.

[0018] A first drive unit 23 is provided on the other side of the first valve stem 22 in the direction of the first axis X. The first drive unit 23 is, for example, an electric motor, and is capable of applying a force to the first valve stem 22 in the direction of the first axis X to move the first valve stem 22 forward and backward.

[0019] A first valve element 25 is attached to the end of the first valve stem 22 on one side in the first axis X direction (i.e., the side on which the steam regulating valve 3 is located when viewed from the main steam stop valve 2). The first valve element 25 has a valve element main body 51 and a small valve element 52. The small valve element 52 is attached integrally to the tip of the first valve stem 22. The small valve element 52 gradually increases in diameter from one side in the first axis X direction to the other side, thereby forming a truncated cone shape centered on the first axis X. When the first valve stem 22 moves back and forth in the first axis X direction, the small valve element 52 also moves back and forth integrally therewith.

[0020] The valve body 51 covers the first valve stem 22 and the small valve body 52 from the outer periphery. Specifically, the valve body 51 has a valve body tip portion 53 and a cylindrical portion 54. The valve body tip portion 53 gradually expands in diameter from one side to the other side in the direction of the first axis X, thereby forming a truncated cone shape centered on the first axis X.

[0021] The surface of the valve element tip portion 53 facing one side in the direction of the first axis X is designated as a first abutment surface S1. The first abutment surface S1 can abut against a first seat surface 61 of a first valve seat 26 (described later). The surface of the valve element tip portion 53 facing the other side in the direction of the first axis X is designated as a second abutment surface S2. A through hole 55 extending in the direction of the first axis X on the first axis X is formed between the second abutment surface S2 and the first abutment surface S1. This through hole 55 can be closed by the small valve element 52 abutting against the second abutment surface S2.

[0022] The cylindrical portion 54 is integrally provided on the other side of the valve body main body 51 in the direction of the first axis X. The cylindrical portion 54 has a cylindrical shape centered on the first axis X. The above-mentioned small valve body 52 and first valve stem 22 are movable forward and backward in the direction of the first axis X in the space on the inner circumferential side of the cylindrical portion 54.

[0023] Furthermore, a locking portion 56 is provided at the end of the cylindrical portion 54 on the other side in the direction of the first axis X. The locking portion 56 has an annular shape centered on the first axis X, and a hole through which the first valve stem 22 is inserted is formed in the center. When the first valve stem 22 is moved toward the other side in the direction of the first axis X, initially the first valve stem 22 is displaced through this hole, while the valve body 51 is stationary. When the first valve stem 22 is moved further from this state, the small valve disc 52 comes into contact with the locking portion 56, and a load is applied to the valve body 51 toward the other side in the direction of the first axis X, causing the valve body 51 to also be displaced.

[0024] The first valve seat 26 is disposed in the first space 90 of the first casing 21 on one side of the valve disc main body 51 in the direction of the first axis X. The first valve seat 26 has a cylindrical shape centered on the first axis X. A first seat surface 61, which is the end face of the first valve seat 26 on the other side in the direction of the first axis X, has a conical shape whose diameter gradually increases from one side to the other side in the direction of the first axis X. A first abutment surface S1 of the valve disc main body 51 can abut against the first seat surface 61. In this case, the main steam stop valve 2 is closed. On the other hand, when the valve disc main body 51 is separated from the first seat surface 61 (i.e., when the main steam stop valve 2 is open), steam that has flowed into the first space 90 through the supply passage 91 flows toward the steam control valve 3 downstream through a gap between the first seat surface 61 and the valve disc main body 51. This steam passage between the main steam stop valve 2 and the steam control valve 3 is called a connection passage 70.

[0025] A ventilator flow path 16 is formed in the connecting flow path 70, extending so as to penetrate the inside and outside of the first casing 21. The downstream end of the ventilator flow path 16 is connected to the condenser 14. Therefore, when the condenser 14 is operating and its interior is in a vacuum state, the negative pressure will reach the connecting flow path 70 through the ventilator flow path 16.

[0026] A physical quantity acquiring unit 27 is provided on the supply flow path 91 in the first casing 21. The physical quantity acquiring unit 27 acquires various physical quantities including, for example, the temperature, pressure, or humidity inside the supply flow path 91, and transmits them as electrical signals to the control device 15, which will be described later. As the physical quantity acquiring unit 27, a known temperature sensor, pressure gauge, humidity sensor, etc., can be used in appropriate combination.

[0027] The first casing 21 is also provided with a first opening / closing sensor 28 that detects the open / closed state of the main steam stop valve 2 by detecting the forward / backward movement position of the first valve stem 22. As the first opening / closing sensor 28, for example, a microswitch or an element that can detect the position and displacement amount of the first valve stem 22 in a non-contact manner is used. The first opening / closing sensor 28 transmits the open / closed state of the steam regulating valve 3 to the control device 15 as an electrical signal.

[0028] (Configuration of steam control valve 3) The steam control valve 3 has a second casing 31, a second valve rod 32, a second drive portion 33, a second valve body 34, a second valve seat 35, and a second opening / closing sensor 36.

[0029] The second casing 31 is connected to one side of the first casing 21 in the direction of the first axis X. The second valve stem 32, the second valve body 34, and the second valve seat 35 are housed in a second space 93 within the second casing 31. The second space 93 communicates with the first space 90 via the above-mentioned connecting flow path 70. In other words, when the main steam stop valve 2 and the steam control valve 3 are in an open state, this second space 93 functions as a flow path for steam.

[0030] The second valve rod 32 is rod-shaped and extends along a second axis Y. The second axis Y extends in the vertical direction intersecting (perpendicular to) the first axis X. The second valve rod 32 can be moved forward and backward in the direction of the second axis Y by a second drive unit 33. As shown in FIG. 3 , the second valve rod 32 has a valve rod body 81 and a valve rod tip portion 82.

[0031] The valve stem body 81 is rod-shaped and extends along the second axis Y. The second drive unit 33 is connected to the upper end of the valve stem body 81. A valve stem tip portion 82 is provided at the lower end of the valve stem body 81. The valve stem tip portion 82 is cylindrical with a diameter slightly larger than that of the valve stem body 81. An internal flow path 83 through which steam flows is formed inside the valve stem tip portion 82. The internal flow path 83 extends in the direction of the second axis Y. The lower end of the internal flow path 83 is open. In addition, a plurality of side holes 84 are formed at midpoints in the up-down direction of the valve stem tip portion 82.

[0032] The second valve body 34 is cylindrical and covers the valve stem tip 82 from the outer periphery. The second valve body 34 is supported so as to be movable back and forth along the second axis Y relative to the second valve stem 32. The lower edge of the inner circumferential surface of the second valve body 34 gradually expands in diameter from bottom to top, forming a conical surface. This surface forms a third abutment surface S3 that can abut against the valve stem tip 82.

[0033] The lower edge of the outer peripheral surface of the second valve body 34 gradually expands in diameter from bottom to top, forming a conical surface. This surface forms a fourth abutment surface S4 that can abut against a second seat surface 85 of the second valve seat 35, which will be described later.

[0034] The second casing 31 is provided with a second opening / closing sensor 36 that detects the open / closed state of the steam control valve 3 by detecting the forward / backward movement position of the second valve stem 32. As with the first opening / closing sensor 28, the second opening / closing sensor 36 may be a microswitch or an element that can detect the position and displacement of the first valve stem 22 in a non-contact manner. The second opening / closing sensor 36 transmits the open / closed state of the steam control valve 3 to the control device 15 as an electrical signal.

[0035] (Configuration of control device 15) Next, the configuration of the control device 15 will be described with reference to Fig. 4. As shown in Fig. 4, the control device 15 has an information acquisition unit 101, a determination unit 102, a drive unit 103, and a storage unit 104.

[0036] The information acquiring unit 101 acquires various pieces of information from the pressure sensor provided in the condenser 14, the physical quantity acquiring unit 27 provided in the supply flow path 91, the first opening / closing sensor 28 provided in the main steam stop valve 2, and the second opening / closing sensor 36 provided in the steam control valve 3. Specifically, this information includes the pressure state in the condenser 14, various physical quantities including the temperature, pressure, or humidity in the supply flow path 91, the open / closed state of the main steam stop valve 2, and the open / closed state of the steam control valve 3. The information acquired by the information acquiring unit 101 is temporarily stored in the memory unit 104.

[0037] The determination unit 102 compares the above various information with predetermined thresholds to determine whether operation to shut down the turbine has begun. As an example, if the main steam stop valve 2 is in a closed state, it can be determined that operation to shut down the turbine has begun. Based on the determination result of the determination unit 102, the drive unit 103 generates and transmits an electric signal to switch the open / close state of the solenoid valve 13.

[0038] Next, an example of a processing flow of the control device 15 will be described with reference to FIG. 5. First, in step S101, the information acquisition unit 101 acquires the open / close state from the first open / close sensor 28 and the second open / close sensor 36. In subsequent steps S102 and S103, the information acquisition unit 101 also acquires the temperature and pressure in the supply passage 91, respectively. In step S104, the determination unit 102 determines whether the main steam stop valve 2 is closed based on the information acquired in step S101. If the determination in step S104 is Yes, then in the subsequent step S105, the determination unit 102 determines whether the inside of the condenser 14 is in a vacuum state. On the other hand, if the determination in step S104 is No, the process returns to step S101 again. If the determination in step S105 is Yes, then in the subsequent step S106, the determination unit 102 determines whether steam is flowing in the supply passage 91. This determination is made comprehensively in consideration of the various physical quantities described above. If the determination in step S105 is No, the process returns to step S101 again. If the determination in step S106 is Yes, the determination unit 102 determines in step S107 whether the steam control valve 3 is closed or not. If the determination in step S107 is Yes, the drive unit 103 sends an electrical signal to the solenoid valve 13 to switch the solenoid valve 13 to an open state. As a result, when the solenoid valve 13 is opened, the leaked steam in the connection flow path 70 flows toward the ventilator flow path 16. If the determination in step S107 is No, the process returns to step S101 again. With this, the processing flow of the control device 15 is completed.

[0039] (Action and effect) Here, there is a possibility that misalignment may occur between the valve disc and the valve seat of the main steam stop valve 2, preventing it from closing completely. This causes steam to flow in through the gap between the valve disc and the valve seat, and the steam flows into the turbine through minute gaps formed in various places in the steam control valve 3 downstream, creating a problem.

[0040] 3, steam leaking from the main steam stop valve 2 flows upward through the gap between the second valve body 34 and the second casing 31, then returns downward through the gap between the second valve body 34 and the second valve stem 32, and finally is discharged downstream, i.e., to the turbine side, through the internal flow path 83 of the second valve stem 32. As a result, the turbine starts to rotate unintentionally. To solve this problem, the present embodiment employs the above-described configurations.

[0041] According to the above configuration, even if the first valve body 25 of the main steam stop valve 2 becomes misaligned with respect to the first valve seat 26 due to some external cause, causing steam to flow from the first space 90 into the connecting passage 70, the steam can be returned to the condenser 14 through the ventilator passage 16. In particular, when the main steam stop valve 2 is in a closed state and a vacuum is created inside the condenser 14, the control device 15 opens the solenoid valve 13 provided between the ventilator passage 16 and the condenser 14. First, by setting the main steam stop valve 2 to be in an apparent closed state as one of the conditions, the solenoid valve 13 is opened only when the turbine is in a state in which it should be stopped. Furthermore, by setting the vacuum state inside the condenser 14 as another condition, steam can be drawn into the ventilator passage 16 from the second space 93 communicating with the condenser 14 by negative pressure when the second space 93 is in a vacuum state. This makes it possible to more reliably recover leaked steam toward the condenser 14. Therefore, the operability of the steam turbine system 1 can be further improved.

[0042] According to the above configuration, even if the turbine needs to be stopped, the control device 15 opens the solenoid valve 13 on the additional condition that steam is flowing through the first space 90. As a result, steam is immediately recovered to the condenser 14 through the ventilator flow path 16. This significantly reduces the time required to stop the turbine. It is also possible to prevent unintended rotation of the turbine due to leaked steam. This further improves the operability of the steam turbine system 1. Furthermore, by making the conditions for opening the solenoid valve 13 stricter, it is possible to more thoroughly confirm and ensure that the turbine needs to be stopped. In other words, it is possible to avoid malfunction or runaway of the control device 15 when there is no request to stop the turbine. This therefore enables more stable operation of the steam turbine system 1.

[0043] According to the above configuration, the control device 15 opens the solenoid valve 13 on the additional condition that the steam control valve 3 is also closed in addition to the main steam stop valve 2. This allows the control device 15 to open the ventilator flow path 16 after more carefully ensuring and confirming that the turbine needs to be stopped. In other words, it is possible to avoid malfunction or runaway of the control device 15 when there is no request to stop the turbine. Therefore, more stable operation of the steam turbine system 1 can be achieved.

[0044] Here, when the first axis X of the main steam stop valve 2 extends horizontally, the first valve stem 22 and the first valve element 25 move back and forth horizontally. In this case, a downward load is applied to the first valve element 25 due to gravity, which tends to cause misalignment between the first valve element 25 and the first valve seat 26. According to the above configuration, even if steam flows from the first space 90 to the second space 93 in an environment or configuration that makes misalignment likely to occur, the steam can be more actively returned to the condenser 14 through the ventilator flow path 16. Therefore, even more stable operation of the steam turbine system 1 can be achieved.

[0045] (Other embodiments) The above describes in detail the embodiments of the present disclosure with reference to the drawings, but the specific configuration is not limited to this embodiment, and design changes and the like are also included within the scope that does not deviate from the gist of the present disclosure.

[0046] For example, as a first modified example and a second modified example of the processing flow of the control device 15, the flows shown in Fig. 6 and Fig. 7 can be adopted. In the example of Fig. 6, step S107 is omitted. In the example of Fig. 7, steps S106 and S107 are omitted. Even with this configuration, the same effects as those described above can be obtained.

[0047] 1 is merely an example, and can be increased or decreased as appropriate depending on the number of turbines and boilers. In either case, the same effects as those described above can be obtained.

[0048] Note that the control device 15 in the embodiment of the present disclosure may change the order of processing as long as appropriate processing is performed.

[0049] The storage unit 104 and other storage devices in the embodiments of the present disclosure may be provided anywhere within a range where appropriate information can be transmitted and received. Furthermore, there may be multiple storage units 104 and other storage devices within a range where appropriate information can be transmitted and received, and data may be stored in a distributed manner.

[0050] The processing steps performed by the control device 15 described above are stored in the form of a program on a recording medium that can be read by the computer 300, and the above processing is performed by reading and executing this program by the computer 300. A specific example of the computer 300 is shown below.

[0051] As shown in FIG. 8, the computer 300 includes a CPU 301 , a main memory 302 , a storage 303 , and an interface 304 . For example, the above-described control device 15 is implemented in a computer 300. The operations of the above-described processing units are stored in the form of a program in a storage 303. A CPU 301 reads the program from the storage 303, loads it into a main memory 302, and executes the above-described processing in accordance with the program. The CPU 301 also allocates a storage area in the main memory 302 corresponding to the above-described storage unit 104 in accordance with the program.

[0052] Examples of storage 303 include a hard disk drive (HDD), a solid state drive (SSD), a magnetic disk, a magneto-optical disk, a compact disc read-only memory (CD-ROM), a digital versatile disc read-only memory (DVD-ROM), and a semiconductor memory. Storage 303 may be an internal medium directly connected to the bus of computer 300, or an external medium connected to computer 300 via interface 304 or a communication line. Furthermore, when this program is distributed to computer 300 via a communication line, computer 300 that receives the program may load the program into main memory 302 and execute the above-mentioned processing. Storage 303 is a non-transitory tangible storage medium.

[0053] The program may also implement some of the functions described above. Furthermore, the program may be a file that can implement the functions described above in combination with a program already recorded in computer 300, a so-called differential file (differential program).

[0054] In addition to or instead of the above configuration, a custom LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device), an ASIC (Application Specific Integrated Circuit), a GPU (Graphics Processing Unit), or similar processing devices may be provided. Examples of PLDs include PAL (Programmable Array Logic), GAL (Generic Array Logic), CPLD (Complex Programmable Logic Device), and FPGA (Field Programmable Gate Array). In this case, some or all of the functions realized by the processor may be realized by the integrated circuit.

[0055] <Additional Notes> The steam turbine system 1 described in each embodiment can be understood, for example, as follows.

[0056] (1) A steam turbine system 1 according to a first aspect includes a main steam stop valve 2 having a first casing 21 that forms a first space 90 containing a first valve element 25 that is movable back and forth along a first axis X, a first valve seat 26 that is capable of abutting against the first valve element 25, and the first valve seat 26; a second casing 21 that forms a second space 93 that contains a second valve element 34 that is movable back and forth along a second axis Y, a second valve seat 35 that has a second seat surface 85 that is capable of abutting against the second valve element 34, and the second valve seat 35; 31, and a connecting flow path 70 connecting the main steam stop valve 2 and the steam control valve 3, wherein a ventilator flow path 16 communicating with an external condenser 14 is formed in the connecting flow path 70, and further comprising an electromagnetic valve 13 provided between the ventilator flow path 16 and the condenser 14, and a control device 15 for controlling the opening and closing state of the electromagnetic valve 13, wherein the control device 15 opens the electromagnetic valve 13 when the main steam stop valve 2 is closed and the inside of the condenser 14 is in a vacuum state.

[0057] According to the above configuration, even if the first valve body 25 of the main steam stop valve 2 becomes misaligned with the first valve seat 26 and steam flows from the first space 90 into the connecting passage 70, the steam can be returned to the condenser 14 through the ventilator passage 16.

[0058] (2) The steam turbine system 1 according to the second aspect is the steam turbine system 1 of (1), wherein the control device 15 further opens the solenoid valve 13 when steam is flowing within the first space 90.

[0059] According to the above configuration, the time required to stop the turbine can be significantly reduced.

[0060] (3) The steam turbine system 1 according to the third aspect is the steam turbine system 1 of (1) or (2), wherein the control device 15 further opens the solenoid valve 13 when the steam control valve 3 is closed.

[0061] According to the above configuration, the ventilator flow path 16 can be opened by the control device 15 after more carefully ensuring and confirming that the turbine is in a state where it is necessary to stop the turbine.

[0062] (4) A steam turbine system 1 according to a fourth aspect is the steam turbine system 1 according to any one of the aspects (1) to (3), wherein the first axis X of the main steam stop valve 2 extends horizontally.

[0063] According to the above configuration, even if steam flows from the first space 90 to the second space 93 in an environment or configuration that is prone to misalignment, the steam can be more actively returned to the condenser 14 through the ventilator flow path 16. [Explanation of symbols]

[0064] 1...Steam turbine system 2...Main steam stop valve 3...Steam control valve 10...Valve gear 11...Recovery flow path 12...Check valve 13...Solenoid valve 14...Condenser 15...Control device 16...Ventilator flow path 21...First casing 22...First valve stem 23...First drive unit 24...Bush 25...First valve disc 26...First valve seat 27...Physical quantity acquisition unit 28...First opening / closing sensor 31...Second casing 32...Second valve stem 33...Second drive unit 34...Second valve disc 35...Second valve seat 36...Second opening / closing sensor 41...Large diameter portion 42...Small diameter portion 51...Valve disc body 52...Small valve disc 53...Valve disc tip portion 54...Cylindrical portion 55...Through-hole 56...Latching portion 61...First seat surface 70...Connecting flow path 81...Valve stem body 82...Valve stem tip portion 83...Internal flow path 84...Side hole 85...Second seat surface 90...First space 91...Supply flow path 92...Step portion 93...Second space 101...Information acquisition unit 102...Determination unit 103...Drive unit 104...Memory unit 300...Computer 301...CPU 302...Main memory 303...Storage 304...Interface S1...First contact surface S2...Second contact surface S3...Third contact surface S4...Fourth contact surface X...First axis Y...Second axis

Claims

1. a main steam stop valve including a first valve body movable back and forth along a first axis, a first valve seat abuttable against the first valve body, and a first casing forming a first space accommodating the first valve body and the first valve seat; a steam control valve including a second valve body movable back and forth along a second axis, a second valve seat having a second seat surface capable of contacting the second valve body, and a second casing forming a second space for accommodating the second valve body and the second valve seat; a connecting passage connecting the main steam stop valve and the steam regulating valve; Equipped with a ventilator flow path communicating with an external condenser is formed in the connecting flow path; a solenoid valve provided between the ventilator flow path and the condenser; a control device that controls the open / close state of the solenoid valve; Furthermore, The control device a main steam stop valve that is in a closed state and a vacuum state is created inside the condenser;

2. The steam turbine system according to claim 1 , wherein the control device further opens the solenoid valve when steam is flowing through the first space.

3. The steam turbine system according to claim 1 or 2, wherein the control device further opens the solenoid valve when the steam control valve is closed.

4. The steam turbine system according to claim 1 or 2, wherein the first axis of the main steam stop valve extends in a horizontal direction.

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