Steam turbine switch box device

Abstract

The present application discloses a switch box device for a steam turbine, which relates to the field of steam turbine equipment and can solve the problem in the prior art that the connecting rod mechanism of the switch box becomes stuck or even fails to move, thus affecting the normal operation of the unit. The switch box device includes a box body and a travel switch, wherein the travel switch includes a travel box and a valve stem rotatably connected to the travel box. The switch box device also includes a driver and a displacement sensor, wherein one end of the driver extends out of the box body and the extended end is connected to the oil motor. Four travel switches are grouped into two groups, and the two groups of travel switches are arranged along the length extension direction of the driver. The two travel switches in each group are symmetrically arranged on both sides of the driver along the length extension direction of the driver. The driver has a toggle assembly integrally formed at both ends along its own length for cooperating with the travel switch. The toggle assembly includes two toggle members symmetrically arranged along the length extension direction of the driver, and the end of the valve stem is located on the moving path of the toggle member.

Description

Technical Field

[0001] The present application relates to the field of steam turbine equipment, and in particular to a switch box device of a steam turbine. Background Art

[0002] A steam turbine is a rotary prime mover that uses steam at a certain temperature and pressure as a working fluid, converting thermal energy into mechanical energy. During operation, it first converts the steam's thermal energy into kinetic energy, and then converts the steam's kinetic energy into mechanical energy. Its primary use is as a prime mover for thermal power generation.

[0003] The steam turbine includes a main steam valve, which is connected to the main steam pipe. The main steam valve is mainly used to control the flow of high-temperature steam entering the cylinder. When the steam turbine needs to be shut down urgently, the main steam valve should be able to close quickly to cut off the steam source. The main steam valve is the main gate of the main steam. When the main steam valve is opened, the steam turbine has a steam source and a driving force; when the main steam valve is closed, the steam turbine is cut off from the steam source and loses its driving force.

[0004] In the prior art, the open and closed states of the main steam valve are fed back to the control system through a switch box. The structure of the switch box is as follows: Figure 1 As shown, the switch box includes a box body 1, four travel switches 3 (two fully open travel switches 3, two fully closed switches), an arc-shaped drive plate 6, a first connecting rod 7, and a second connecting rod 8. The four travel switches 3 are sequentially connected to the box body 1 along the length direction of the box body 1. The travel switch 3 includes a travel box 31 and a valve stem 32 rotatably connected to the travel box 31. The arc-shaped drive plate 6 is rotatably connected to the box body 1. Four shift rods 61 are connected to the edge of the arc-shaped drive plate 6. The four shift rods 61 correspond one-to-one to the valve stems 32 of the four travel switches 3. One end of the first connecting rod 7 is fixedly connected to the center of the arc-shaped drive plate 6, and the other end extends out of the box body 1. The extended end is hinged to one end of the second connecting rod 8, and the other end of the second connecting rod 8 is connected to the oil motor 9. The oil motor 9 is also used to drive the opening and closing of the main steam valve. In this way, the opening and closing of the main steam valve are synchronized with the movement of the second connecting rod 8. The second connecting rod 8, the first connecting rod 7, and the arc-shaped drive plate 6 are connected to form a connecting rod mechanism. The oil motor 9 drives the second connecting rod 8 to move back and forth in a straight line along the length extension direction of the second connecting rod 8. The second connecting rod 8 drives the first connecting rod 7 to rotate back and forth (swing back and forth). The first connecting rod 7 then drives the arc-shaped drive plate 6 to rotate. The lever 61 on the arc-shaped drive plate 6 rotates with the rotation of the arc-shaped drive plate 6 to toggle the valve stem 32 of the travel switch 3. The rotation of the valve stem 32 opens the travel switch 3. The travel switch 3 transmits an electrical signal to the control system of the steam turbine to feedback whether the main steam valve is currently open or closed.

[0005] However, the connecting rod mechanism formed by the second connecting rod 8, the first connecting rod 7, and the arc-shaped drive plate 6 is connected to each other at the connection points by fasteners (bolts, nuts, etc.). The more connection points there are, the higher the installation precision requirements are. However, as the switch box is used repeatedly for a long time, especially at the connection points, it is easy for one or more of the above components to have problems such as position deviation and loose connection due to low installation precision or long-term stress, and the accumulated error is large. Since the motion transmission mode is converted from linear motion to rotational motion, the motion mode is more complicated, which can easily lead to problems such as jamming or even inability to move of the connecting rod mechanism, which may seriously cause breakage and affect the normal operation of the unit. Summary of the Invention

[0006] To this end, the present application provides a switch box device for a steam turbine to solve the problem in the prior art that the connecting rod mechanism of the switch box becomes stuck or even fails to move, thereby affecting the normal operation of the unit.

[0007] In order to achieve the above objectives, this application provides the following technical solutions:

[0008] A switch box device for a steam turbine comprises a box body, four travel switches connected to the box body, the travel switch comprising a travel box connected to the inner wall of the box body, a valve stem rotatably connected to the travel box, the switch box device further comprising a driving member located in the box body and a displacement sensor connected to the box body, the displacement sensor being used to measure the movement distance of the driving member and to feed back to a monitoring system, one end of the driving member extending out of the box body, and the extended end being connected to an oil motor for driving the driving member to reciprocate along the direction of its own length extension, the four travel switches being grouped in two, and the two groups being The travel switches are arranged along the length extension direction of the driving member, and the two travel switches in each group are symmetrically arranged on both sides of the driving member along the length extension direction of the driving member. The driving member is integrally formed with a toggle assembly for cooperating with the travel switch at both ends along its own length. The two toggle assemblies correspond one-to-one with the two groups of travel switches. The toggle assembly includes two toggle members symmetrically arranged along the length extension direction of the driving member. The two toggle members correspond one-to-one with the valve stems of the two travel switches in the same group, and the end of the valve stem away from the travel box is located on the moving path of the toggle member.

[0009] Preferably, the driving member is a driving plate, and the toggle member is integrally formed on a side of the driving plate.

[0010] Preferably, the end of the valve stem away from the box body is connected to a pulley.

[0011] Preferably, a curved surface is formed at the connection between the toggle member and the driving plate.

[0012] Preferably, the valve stem is connected to the box body through a rotating rod, one end of the rotating rod is rotated and connected to the box body, and the other end of the rotating rod is connected to a connecting piece that matches the valve stem, and the valve stem is slidably connected to the slot of the connecting piece along the direction of its own length extension, and the valve stem is provided with a long hole passing through itself along the direction of its own length extension, and the valve stem is detachably connected to the connecting piece through a fastener, and the fastener is passed through the long hole.

[0013] Preferably, the driving member is connected to the oil motor through a connecting plate, one end of the driving member is welded to the connecting plate, the connecting plate includes a first plate welded to one end of the driving member, and a second plate integrally formed on an end of the first plate away from the connecting plate, the second plate is connected to the oil motor, the first plate is perpendicular to the second plate, the second plate is parallel to the driving member, the first plate is located on the outside of the box body, and the first plate extends beyond the outer wall of the box body in the direction toward the second plate.

[0014] Preferably, the displacement sensor includes a shell, a coil frame connected to the inner cavity of the shell, a primary coil connected to the coil frame, and a secondary coil connected to the coil frame. The primary coil and the secondary coil form a channel for the rod-shaped iron core to slide along the length direction of the shell. One end of the rod-shaped iron core is connected to a pull rod, and the pull rod extends out of the shell, and the extended end is connected to the first plate.

[0015] Preferably, the first plate is provided with a connecting hole, one end of the pull rod is connected to a connecting section for passing through the connecting hole, the diameter of the pull rod is larger than the diameter of the connecting hole, the connecting section passes through the connecting hole away from one end of the pull rod, and the passing end of the connecting section is threadedly connected with multiple nuts.

[0016] This application has the following advantages:

[0017] When the hydraulic motor drives the main steam valve to open and close, it synchronously drives the driving member to move along the length extension direction of the driving member. During the reciprocating movement of the driving member, the end of the valve stem away from the stroke box is located in the movement path of the toggle member. The toggle member then toggles the valve stem to rotate. The rotating valve stem opens the stroke switch to feedback whether the main steam valve is currently open or closed. Compared with the connecting rod mechanism in the prior art, the driving member of the present application is directly connected to the hydraulic motor, and the driving member and the toggle member are integrally connected. The driving member has a simple structure and a simple motion relationship. As a result, the installation and maintenance of the driving member are relatively simple, and the problems of high installation precision requirements, component position deviation, loose connections, etc. caused by multiple connection locations are effectively avoided, thereby avoiding the problem of jamming or even failure of operation. The displacement sensor can measure the movement distance of the driving member in real time. Since the opening and closing of the driving member and the main steam valve are synchronized, the degree of opening and closing of the main steam valve can be determined by measuring the movement distance of the driving member. The monitoring system can automatically adjust the opening and closing of the main steam valve through the control system based on the detected opening and closing degree. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] To more intuitively illustrate the prior art and the present application, several exemplary drawings are provided below. It should be understood that the specific shapes and structures shown in the drawings should not generally be considered as limiting conditions for implementing the present application. For example, based on the technical concepts disclosed in this application and the exemplary drawings, those skilled in the art are capable of easily making routine adjustments or further optimizations to the addition / reduction / attribution division of certain units (components), the specific shapes, positional relationships, connection methods, and dimensional ratios.

[0019] Figure 1 A schematic structural diagram of a switch box in the background technology of this application;

[0020] Figure 2 A schematic diagram of the overall structure of a switch box device for a steam turbine provided in one embodiment of the present application;

[0021] Figure 3 for Figure 2 Schematic diagram of part of the structure;

[0022] Figure 4 for Figure 3 Side view of

[0023] Figure 5 for Figure 3 Top view of the middle structure;

[0024] Figure 6 for Figure 3 Schematic diagram of part of the structure;

[0025] Figure 7 for Figure 6 Side view of

[0026] Figure 8 for Figure 6 Partial cross-sectional view of the middle structure;

[0027] Figure 9 A schematic diagram of the overall structure of a travel switch of a switch box device of a steam turbine provided by one embodiment of the present application;

[0028] Figure 10 for Figure 9 Schematic diagram of part of the structure.

[0029] Description of reference numerals:

[0030] 1. Box body; 2. Driving member; 21. Toggle member; 3. Travel switch; 31. Travel box; 311. Connecting member; 3111. Slot; 32. Valve stem; 321. Pulley; 322. Fastener; 323. Long hole; 4. Displacement sensor; 41. Housing; 411. Channel; 42. Rod-shaped core; 43. Pull rod; 431. Connecting section; 432. Nut; 5. Connecting plate; 51. First plate; 52. Second plate; 6. Arc-shaped driving plate; 61. Toggle rod; 7. First connecting rod; 8. Second connecting rod; 9. Oil motor. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0032] In the description of the present application: the terms "inside" and "outside" refer to the inside and outside of the corresponding component contours; the terms "first" and "second" are intended to distinguish the objects referred to, and the terms "including", "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or equipment that includes a series of steps or units is not necessarily limited to those steps or units that have been explicitly listed, but may also include other steps or units that are not explicitly listed but are inherent to these processes, methods, products or equipment, or steps or units added based on further optimization schemes conceived in the present application.

[0033] refer to Figure 2-5The present application discloses a switch box device for a steam turbine, comprising a box body 1, four travel switches 3 connected to the box body 1, the travel switch 3 comprising a travel box 31 connected to the inner wall of the box body 1, and a valve stem 32 rotatably connected to the travel box 31. The switch box device also comprises a driving member 2 located in the box body 1 and a displacement sensor 4 connected to the box body 1, the displacement sensor 4 being used to measure the movement distance of the driving member 2 and to feed back to the monitoring system, one end of the driving member 2 extending out of the box body 1, and the extending end being connected to an oil motor 9 for driving the driving member 2 to reciprocate along the direction of its own length extension, the four travel switches 3 being a group of two, and the two groups of travel switches 3 are arranged along the length extension direction of the driving member 2 (a certain gap exists between the two groups of travel switches 3). The two travel switches 3 in each group are symmetrically arranged on both sides of the driving member 2 along the length extension direction of the driving member 2. The driving member 2 is integrally formed with a toggle assembly for cooperating with the travel switch 3 at both ends along its own length. The two toggle assemblies correspond one-to-one with the two groups of travel switches 3. The toggle assembly includes two toggle members 21 symmetrically arranged along the length extension direction of the driving member 2. The two toggle members 21 correspond one-to-one with the valve stems 32 of the two travel switches 3 in the same group. The end of the valve stem 32 away from the travel box 31 is located on the moving path of the toggle member 21.

[0034] When the oil motor 9 drives the valve of the main steam valve to open and close, it synchronously drives the driving member 2 to move along the length extension direction of the driving member 2. During the reciprocating movement of the driving member 2, the end of the valve stem 32 away from the travel box 31 is located on the moving path of the toggle member 21, and the toggle member 21 toggles the valve stem 32 to rotate. The rotating valve stem 32 opens the travel switch 3 to feedback whether the main steam valve is currently open or closed. Compared with the connecting rod mechanism in the prior art, the driving member 2 of the present application is directly connected to the oil motor 9, and the driving member 2 is integrally connected to the toggle member 21. The structure is simple and the movement relationship is simple, so the installation and maintenance of the driving member 2 are relatively simple, and it effectively avoids the problems of high installation precision requirements, component position deviation, loose connection, etc. caused by multiple connection positions, thereby avoiding the problem of jamming or even inability to move; the displacement sensor 4 can measure the movement distance of the driving member 2 in real time. Since the opening and closing of the driving member 2 and the main steam valve are synchronized, the degree of opening and closing of the main steam valve can be known by measuring the movement distance of the driving member 2. The monitoring system can automatically adjust the opening and closing of the main steam valve through the control system according to the detected opening and closing degree.

[0035] It is further explained that the four travel switches 3 are two fully-open travel switches 3 and two fully-closed travel switches 3. The two fully-open travel switches 3 form a group, and the two fully-closed travel switches 3 form a group. The two fully-open travel switches 3 transmit electrical signals to two independent control systems (DCS control system, DEH control system) respectively, and the same is true for the two fully-closed travel switches 3. The above-mentioned travel switches 3 are prior art and will not be described in detail. It should be emphasized that the valve stem 32 is rotatably connected to the travel box 31. When the toggle member 21 drives the valve stem 32 to rotate (after the toggle member 21 disengages from the valve stem 32), the elastic recovery component in the travel box 31 can restore the valve stem 32 to its original state. In this way, the toggle member 21 moves back and forth to toggle the valve stem 32, thereby realizing signal feedback of the travel switch 3.

[0036] The switch box device of the steam turbine involved in this application can be applied not only to the main steam valve, but also to other valves, such as regulating valves.

[0037] In some embodiments, the distance between the two groups of travel switches 3 is smaller than the distance between the two toggle components.

[0038] The driving member 2 is a driving plate, and the shifting member 21 is integrally formed on the side of the driving plate.

[0039] The end of the valve stem 32 away from the box body 1 is connected to a pulley 321. The pulley 321 can convert the contact friction of the valve stem 32 contacting the toggle member 21 into rolling friction, thereby reducing friction and also reducing wear between the valve stem 32 and the toggle member 21.

[0040] The connection between the toggle member 21 and the drive plate can be formed with an arc surface. In this way, the connection strength between the toggle member 21 and the drive plate can be improved to avoid stress concentration.

[0041] refer to Figure 9-10 The valve stem 32 is connected to the housing 1 via a rotating rod. One end of the rotating rod is rotated and connected to the housing 1. The other end of the rotating rod is connected to a connecting piece 311 that matches the valve stem 32. The valve stem 32 slides along its length and is connected to the slot 3111 of the connecting piece 311. The valve stem 32 has an elongated hole 323 extending through it. The valve stem 32 is detachably connected to the connecting piece 311 via a fastener 322, which is inserted into the elongated hole 323. In this way, when installing the driver 2, the position of the valve stem 32 can be adjusted according to the degree of contact between the toggle member 21 and the valve stem 32. The fastener 322 can be a bolt. After the valve stem 32 slides along the slot 3111 to select the appropriate position, the bolt is inserted into the elongated hole 323 and tightened onto the connecting piece 311 (the nut 432 of the bolt abuts against the valve stem 32, and the nut 432 clamps the valve stem 32 to the connecting piece 311).

[0042] refer to Figure 2-7 The driving member 2 is connected to the oil motor 9 through the connecting plate 5. One end of the driving member 2 is welded to the connecting plate 5. The connecting plate 5 includes a first plate 51 welded to one end of the driving member 2 and a second plate 52 integrally formed on the end of the first plate 51 away from the connecting plate 5. The second plate 52 is connected to the oil motor 9. The first plate 51 is perpendicular to the second plate 52. The second plate 52 is parallel to the driving member 2. The first plate 51 is located on the outside of the box body 1, and the first plate 51 extends beyond the outer wall of the box body 1 in the direction toward the second plate 52. When the first plate 51 is against the outer wall of the box body 1, the first plate 51 can prevent the driving member 2 from moving further. In this way, when the oil motor 9 fails, the connecting plate 5 does not drive the driving member 2 to impact the inner wall of the box body 1. In particular, when the end of the driving member 2 away from the first plate 51 impacts the inner wall of the box body 1, it is easy to cause the driving member 2 to be deformed by force at the connection between the driving member 2 and the first plate 51, causing damage to related components of the switch box device. In addition, compared with the detachable connection method through other connecting members 311, the welding method has a more stable and reliable connection relationship, which can avoid loosening at the connection.

[0043] It should be emphasized that the reference Figure 5 The oil motor 9 drives the second plate 52 to move linearly along the length extension direction of the driving member 2 by swinging. The second plate 52 can be connected to a corresponding limiting structure to limit the movement direction of the second plate 52 to the above-mentioned linear movement direction. For example, a limiting rod along the length extension direction of the driving member 2 is connected to the bottom of the second plate 52, and a limiting block that cooperates with the limiting rod is connected to the outer wall of the box body 1. The limiting rod passes through the limiting hole of the limiting block, and the hole wall of the limiting hole constrains the limiting rod to move linearly only along the length extension direction of the driving member 2.

[0044] refer to Figure 3 、 Figure 4 、 Figure 6 、 Figure 7 and Figure 8 The displacement sensor 4 includes a shell 41, a coil skeleton (not shown in the figure) connected to the inner cavity of the shell 41, a primary coil (not shown in the figure) connected to the coil skeleton, and a secondary coil (not shown in the figure) connected to the coil skeleton. The primary coil and the secondary coil form a channel 411 for the rod-shaped iron core 42 to slide along the length direction of the shell 41. One end of the rod-shaped iron core 42 is connected to a pull rod 43, which extends out of the shell 41, and the protruding end is connected to the first plate 51. The shell 41 is connected to the inner wall of the box body 1 through a fastener 322.

[0045] The displacement sensor 4 is a prior art. The pull rod 43 pulls the rod-shaped iron core 42 to move back and forth in the channel 411. The resistance value of the displacement sensor 4 changes, and the distance moved can be measured. The pull rod 43 is connected to the first plate 51. The first plate 51 moves synchronously with the driving member 2 and the second plate 52. Therefore, the degree of opening and closing of the main steam valve is known. The specific principle and structure of the displacement sensor 4 will not be described in detail in this application.

[0046] The displacement sensor 4 may be an LVDT displacement sensor (linear displacement sensor).

[0047] refer to Figure 8 The first plate 51 defines a connection hole. A connecting segment 431 is connected to one end of the tie rod 43, which is designed to pass through the hole. The diameter of the tie rod 43 is larger than the hole. The end of the connecting segment 431, distal from the tie rod 43, passes through the hole. Multiple nuts 432 (typically two) are threaded onto the protruding end of the connecting segment 431. These nuts 432 are screwed onto the protruding ends of the connecting segment 431 in sequence, preventing vibration from loosening the nuts 432 and improving system reliability.

[0048] The technical features of the above embodiments can be combined arbitrarily (as long as there is no contradiction in the combination of these technical features). In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described; these embodiments that are not explicitly written should also be considered to be within the scope of this specification.

[0049] The present application has been described in a relatively specific and detailed manner through general explanations and specific embodiments. It should be understood that, based on the technical concept of the present application, several conventional adjustments or further innovations may be made to these specific embodiments; however, as long as they do not depart from the technical concept of the present application, the technical solutions obtained by such conventional adjustments or further innovations also fall within the scope of protection of the claims of the present application.

Claims

1. A switch box device for a steam turbine, comprising a box body, four travel switches connected to the box body, the travel switches comprising a travel box connected to the inner wall of the box body, and a valve stem rotatably connected to the travel box, characterized in that: The switch box device also includes a driving member located in the box body and a displacement sensor connected to the box body, the displacement sensor is used to measure the movement distance of the driving member and feed back to the monitoring system, one end of the driving member extends out of the box body, and the extended end is connected to an oil motor for driving the driving member to reciprocate along the length extension direction of the driving member, the four travel switches are grouped into two, the two groups of travel switches are arranged along the length extension direction of the driving member, the two travel switches in each group are symmetrically arranged on both sides of the driving member along the length extension direction of the driving member, the driving member is integrally formed with a toggle assembly for cooperating with the travel switch at both ends along its own length, the two toggle assemblies correspond one-to-one with the two groups of travel switches, the toggle assembly includes two toggle members symmetrically arranged along the length extension direction of the driving member, the two toggle members correspond one-to-one with the valve stems of the two travel switches in the same group, and the end of the valve stem away from the travel box is located on the moving path of the toggle member; The valve stem is connected to the box body via a rotating rod, one end of the rotating rod is rotated and connected to the box body, and the other end of the rotating rod is connected to a connecting piece that matches the valve stem. The valve stem is slidably connected to the slot of the connecting piece along its own length extension direction. The valve stem is provided with an elongated hole that passes through the valve stem along its own length extension direction. The valve stem is detachably connected to the connecting piece via a fastener, and the fastener is inserted into the elongated hole. The driving member is connected to the oil motor through a connecting plate, one end of the driving member is welded to the connecting plate, the connecting plate includes a first plate welded to one end of the driving member, and a second plate integrally formed on an end of the first plate away from the connecting plate, the second plate is connected to the oil motor, the first plate is perpendicular to the second plate, the second plate is parallel to the driving member, the first plate is located on the outside of the box body, and the first plate extends beyond the outer wall of the box body in a direction toward the second plate.

2. The switch box device of the steam turbine according to claim 1, characterized in that: The driving member is a driving plate, and the shifting member is integrally formed on a side of the driving plate.

3. The switch box device of a steam turbine according to claim 1 or 2, characterized in that: The end of the valve stem away from the box body is connected with a pulley.

4. The switch box device of the steam turbine according to claim 2, characterized in that: An arc surface is formed at the connection between the toggle member and the driving plate.

5. The switch box device of the steam turbine according to claim 1, characterized in that: The displacement sensor includes a shell, a coil frame connected to the inner cavity of the shell, a primary coil connected to the coil frame, and a secondary coil connected to the coil frame. The primary coil and the secondary coil form a channel for the rod-shaped iron core to slide along the length direction of the shell. One end of the rod-shaped iron core is connected to a pull rod, which extends out of the shell and the protruding end is connected to the first plate. The shell is connected to the inner wall of the box body through fasteners.

6. The switch box device of the steam turbine according to claim 5, characterized in that: The first plate is provided with a connecting hole, and one end of the pull rod is connected to a connecting section for passing through the connecting hole. The diameter of the pull rod is larger than the diameter of the connecting hole. The connecting section passes through the connecting hole away from the end of the pull rod, and the passing end of the connecting section is threadedly connected with multiple nuts.

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