Pneumatic emergency trip automatic protection system of small steam turbine

Abstract

The invention relates to a pneumatic emergency trip automatic protection system for a small steam turbine. The pneumatic emergency trip automatic protection system comprises compressed air, an emergency trip system and a steam shut-off valve connected with the emergency trip system. A pneumatic control valve and an air cylinder are arranged between the emergency trip system and the steam shut-off valve, the output end of the emergency trip system is connected with the pneumatic control valve, and the pneumatic control valve is communicated with the air cylinder; a branch is arranged at the input end of the emergency trip system, the output end of the branch is communicated with an air inlet channel of the pneumatic control valve, and compressed air flowing through the branch enters the air cylinder through the pneumatic control valve. The emergency trip system controls and switches the flow direction of air in the pneumatic control valve and the air cylinder through compressed air conveyed by the emergency trip system so as to control the steam shut-off valve connected with the air cylinder to be opened or closed. The flow direction of the gas in the pneumatic control valve can be automatically switched according to the switching-on state or the emergency trip state of the small steam turbine, so that the flow direction of the compressed gas in the air cylinder is changed, the steam shut-off valve connected with the air cylinder is controlled to be opened or closed, and steam is conveyed or prevented from entering the small steam turbine.

Description

Technical Field

[0001] The invention relates to a small steam turbine pneumatic emergency tripping automatic protection system, belonging to the technical field of steam turbines. Background Art

[0002] At present, the emergency shutdown automatic protection system of small steam turbines used for towing equipment mostly adopts hydraulic system. The system needs to be equipped with hydraulic oil station, oil motor and valve. The system has high operating pressure and complex design. Oil needs to be filtered regularly during operation. The maintenance workload is large, and once oil leakage occurs, it will cause fire accidents.

[0003] A Chinese patent with announcement number CN206477889U discloses a steam turbine starting lock system, including a cylinder, a compressed air system connected to the cylinder, and a lock handle, one end of the lock handle is connected to a hitch, the bottom of the hitch is connected to a slide valve, one end of the slide valve is connected to an oil injection test device, and the other end is connected to an oil overflow valve, wherein: the oil injection test device and the oil overflow valve are only connected to the main oil pump through an automatic shutdown oil pipe, the automatic shutdown oil pipe is connected to the upper cavity of diaphragm valve a, one end of the lower cavity of diaphragm valve a is connected to the AST oil main pipe, and the other end is connected to diaphragm valve b, the upper cavity outlet of diaphragm valve b is connected to the solenoid valve c to the air pipe through an overflow vent pipe, and the upper cavity inlet of diaphragm valve b is connected to the solenoid valve b to the compressed air intake system through a compressed air pipe. It controls the oil amount in the AST oil pipe by adding compressed air pipelines and solenoid valves, thereby controlling the lock of the steam turbine. Although compressed air is introduced, it still needs to cooperate with the oil pump, and there is still a risk of fire accidents. Summary of the invention

[0004] In order to overcome the above problems, the present invention provides a small steam turbine pneumatic emergency shut-off automatic protection system, which enables the gas flow direction in the air control valve to be automatically switched according to whether the small steam turbine is in a locked state or an emergency shut-off state, thereby changing the flow direction of the compressed gas in the cylinder, and then controlling the steam shut-off valve connected thereto to open or close, so as to deliver or prevent steam from entering the small steam turbine.

[0005] The technical solution of the present invention is as follows:

[0006] A pneumatic emergency shut-off automatic protection system for a small steam turbine comprises compressed air, an emergency shut-off system, and a steam shut-off valve connected to the emergency shut-off system; an air-controlled valve and a cylinder are arranged between the emergency shut-off system and the steam shut-off valve, the output end of the emergency shut-off system is connected to the air-controlled valve, and the air-controlled valve is communicated with the cylinder; a branch is arranged at the input end of the emergency shut-off system, the output end of the branch is communicated with the air inlet passage of the air-controlled valve, and the compressed air flowing through the branch enters the cylinder through the air-controlled valve; the emergency shut-off system controls and switches the air-controlled valve and the gas flow direction in the cylinder through the compressed air it delivers, so as to control the steam shut-off valve connected to the cylinder to be opened or closed.

[0007] Furthermore, the cylinder is provided with a piston slidably connected thereto, the upper chamber of the cylinder is above the piston, and the lower chamber of the cylinder is below the piston; a spring is fixedly connected to the top of the piston, the other end of the spring is fixedly connected to the top of the cylinder, and the bottom of the piston is fixedly connected to the steam shut-off valve through a rod body.

[0008] Furthermore, when the compressed air delivered by the emergency shut-off system acts on the air-controlled valve, the air inlet passage is connected to the lower chamber, and the exhaust passage is connected to the upper chamber; the compressed gas delivered by the branch enters the lower chamber through the air inlet passage, and the gas in the upper chamber is discharged through the exhaust passage.

[0009] Furthermore, when the emergency shut-off system does not deliver compressed air, the air intake passage is connected to the upper chamber, and the exhaust passage is connected to the lower chamber; the compressed gas delivered by the branch enters the upper chamber through the air intake passage, and the gas in the lower chamber is discharged through the exhaust passage.

[0010] Furthermore, the emergency shut-off system includes a push-rod type mechanical shut-off valve and a manual emergency stop button valve which are sequentially connected in series.

[0011] Furthermore, an air filter valve, a pressure reducing valve and an oil mist collector are sequentially arranged in series at the input end of the push rod type mechanical shut-off valve; and the branch is placed between the oil mist collector and the push rod type mechanical shut-off valve.

[0012] Furthermore, an electromagnetic reversing valve is connected in series on the branch line.

[0013] Furthermore, a stop valve is connected in series on the input end of the air filter valve, the pipeline between the oil mist collector and the electromagnetic reversing valve, and the pipeline between the oil mist collector and the push rod type mechanical shut-off valve.

[0014] Furthermore, the electromagnetic reversing valve, the push rod type mechanical shut-off valve, the manual emergency stop button valve, and the output end of the exhaust channel are all provided with a muffler.

[0015] Furthermore, a one-way shut-off valve is connected in series on the pipeline between the air-controlled valve and the lower chamber.

[0016] The present invention has the following beneficial effects:

[0017] 1. The present invention divides compressed gas into two paths: a control gas source and a power gas source, so that the control gas source can automatically switch the gas flow direction in the gas control valve according to the small steam turbine shutdown or emergency shutdown state, thereby changing the flow direction of the power gas source in the cylinder to control the opening or closing of the steam shut-off valve connected to the cylinder, thereby realizing the control of steam transportation.

[0018] 2. The present invention realizes the control of the steam shut-off valve through compressed air throughout the whole process, and uses the air filter valve, pressure reducing valve and oil mist valve to filter, reduce pressure and lubricate the compressed air, which is beneficial to increase the service life of the equipment and reduce the risk of fire accidents.

[0019] 3. The present invention realizes the segmented maintenance of the pneumatic emergency trip automatic protection system of the small steam turbine through the cooperation of the stop valve and the electromagnetic reversing valve, which is conducive to finding the maintenance point as soon as possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0021] The reference numerals in the figure represent:

[0022] 1. Emergency shut-off system; 11. Push-rod type mechanical shut-off valve; 12. Manual emergency stop button valve; 13. Air filter valve; 14. Pressure reducing valve; 15. Oil mist collector; 2. Steam shut-off valve; 3. Air control valve; 31. Inlet passage; 32. Exhaust passage; 4. Cylinder; 41. Upper chamber; 42. Lower chamber; 43. Piston; 44. Spring; 45. Rod body; 5. Branch; 6. Solenoid reversing valve; 7. Stop valve; 8. Muffler; 9. One-way shut-off valve. DETAILED DESCRIPTION

[0023] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] See also Figure 1 A pneumatic emergency shut-off automatic protection system for a small steam turbine comprises an emergency shut-off system 1 for conveying compressed gas, and a steam shut-off valve 2 connected to the emergency shut-off system 1; when the small steam turbine is operating normally, the emergency shut-off system 1 is not started, and the emergency shut-off system 1 controls the steam shut-off valve 2 to open through the compressed gas conveyed by the emergency shut-off system 1, so that steam can continue to enter the small steam turbine, and the small steam turbine maintains normal operation; when any variable of the small steam turbine is at the shut-off level, the emergency shut-off system 1 is started, and the emergency shut-off system 1 controls the steam shut-off valve 2 to switch to a closed state through the compressed gas conveyed by the emergency shut-off system 1, so as to prevent steam from entering the small steam turbine, and the small steam turbine is shut down.

[0025] Furthermore, an air-controlled valve 3 and a cylinder 4 are provided between the emergency shut-off system 1 and the steam shut-off valve 2, wherein the output end of the emergency shut-off system 1 is connected to the air-controlled valve 3, the air inlet passage 31 of the air-controlled valve 3 is connected to the lower chamber 42 of the cylinder 4, and the exhaust passage 32 of the air-controlled valve 3 is connected to the upper chamber 41 of the cylinder 4.

[0026] The input end of the emergency shut-off system 1 is divided into a branch 5, and the output end of the branch 5 is connected to the air inlet channel 31 of the air control valve 3. The compressed air flowing through the branch 5 enters the cylinder 4 through the air control valve 3 as a power air source; when the compressed gas delivered by the emergency shut-off system 1 is used as a control air source to control the flow direction of the gas in the air control valve 3, the flow direction of the power air source in the cylinder 4 changes accordingly, thereby affecting the opening or closing of the steam shut-off valve 2.

[0027] Furthermore, a piston 43 is provided in the cylinder 4 and is slidably connected thereto. The interior of the cylinder 4 is divided into an upper chamber 41 and a lower chamber 42 by the piston 43. A spring 44 is fixedly connected to the top of the piston 43, and the other end of the spring 44 is fixedly connected to the top of the cylinder 4. The bottom of the piston 43 is fixedly connected to the steam shut-off valve 2 through a rod body 45.

[0028] Furthermore, the emergency shut-off system 1 comprises a mandrel-type mechanical shut-off valve 11 and a manual emergency stop button valve 12 which are sequentially arranged in series, and the mandrel-type mechanical shut-off valve 11 and the manual emergency stop button valve 12 are connected via a pipeline.

[0029] When the gate is closed, the compressed gas delivered by the emergency trip system 1 acts on the air-controlled valve 3. At this time, the compressed air delivered by the branch 5 enters the lower chamber 42 of the cylinder 4 through the air inlet channel 31 of the air-controlled valve 3. The upper chamber 41 of the cylinder 4 is connected with the exhaust channel 32 of the air-controlled valve 3. When the pressure in the lower chamber 42 continues to increase, the gas in the upper chamber 41 is continuously discharged through the exhaust channel 32 of the air-controlled valve 3. The piston 43 overcomes the spring force and is pushed upward, thereby opening the steam shut-off valve 2, and steam enters the small steam turbine. At this time, the electromagnetic reversing valve 6 is in a power-off state.

[0030] When any variable of the small steam turbine is at the shut-off level, the emergency shut-off system 1 is activated, and the compressed gas is discharged through the push rod type mechanical shut-off valve 11. The compressed gas cannot act on the air control valve 3, and the gas flow direction in the air control valve 3 changes. At this time, the air inlet channel 31 of the air control valve 3 is connected with the upper chamber 41 of the cylinder 4, and the exhaust channel 32 of the air control valve 3 is connected with the lower chamber 42 of the cylinder 4. The compressed air transported by the branch 5 is sent into the upper chamber 41 of the cylinder 4. When the pressure in the upper chamber 41 continues to increase, the gas in the lower chamber 42 is continuously discharged through the exhaust channel 32 of the air control valve 3, and the piston 43 moves downward under the action of the spring force, thereby closing the steam shut-off valve 2 to prevent steam from entering the small steam turbine.

[0031] Furthermore, in order to reduce the damage to the equipment caused by impurities in the compressed air and increase the smoothness of the equipment use, the input end of the push rod type mechanical shut-off valve 11 is sequentially arranged in series with an air filter valve 13, a pressure reducing valve 14, and an oil mist collector 15, which respectively filter impurities, reduce pressure, and lubricate the compressed air flowing through; wherein, the branch 5 is arranged between the oil mist collector 15 and the push rod type mechanical shut-off valve 11.

[0032] Furthermore, stop valves 7 are arranged in series on the input end of the air filter valve 13, the pipeline between the oil mist collector 15 and the electromagnetic reversing valve 6, and the pipeline between the oil mist collector 15 and the push rod type mechanical shut-off valve 11, so as to facilitate the segmented maintenance of the entire pneumatic emergency shut-off automatic protection system.

[0033] Furthermore, in order to reduce the noise generated when exhausting the gas, a muffler 8 is provided at the output end of the electromagnetic reversing valve 6, the push rod type mechanical shut-off valve 11, the manual emergency stop button valve 12, and the exhaust channel 32 of the air control valve 3.

[0034] Furthermore, a one-way shut-off valve 9 is connected in series on the pipeline between the gas control valve 3 and the lower chamber 42 to control the flow of gas delivered to the lower chamber 42 .

[0035] Working principle of the present invention:

[0036] See also Figure 1 When the brake is closed, the compressed gas flows through the air filter valve 13, the pressure reducing valve 14, and the oil mist collector 15 in sequence and is divided into two paths. One path is transported through the emergency shut-off system 1 as a control gas source for controlling the flow direction of the gas in the gas-controlled valve 3, and the other path is transported through the branch 5 as a power gas source for controlling the opening or closing of the steam shut-off valve 2: the compressed gas flows through the top rod type mechanical shut-off valve 11 and the manual emergency stop button valve 12 in sequence and acts on the gas-controlled valve 3. At this time, the air intake channel 31 of the gas-controlled valve 3 is connected with the lower chamber 42 of the cylinder 4, and the exhaust channel 32 of the gas-controlled valve 3 is connected with the upper chamber 41 of the cylinder 4. The compressed gas transported by the branch 5 flows through the air intake channel 31 and enters the lower chamber 42, and continuously accumulates in the lower chamber 42, pushing the piston 43 to move upward, and discharging the gas in the upper chamber 41 through the exhaust channel 32, so as to open the steam shut-off valve 2, so that the steam can enter the small steam turbine, and the small steam turbine operates normally.

[0037] When any variable of the small steam turbine is at the shut-off level, the push rod type mechanical shut-off valve 11 is activated, and the control air source is leaked through the push rod type mechanical shut-off valve 11. The emergency shut-off system 1 cannot deliver the control air source. At this time, the gas flow direction in the air control valve 3 changes, and the air inlet channel 31 of the air control valve 3 is connected with the upper chamber 41 of the cylinder 4, and the exhaust channel 32 of the air control valve 3 is connected with the lower chamber 42 of the cylinder 4. The compressed gas delivered by the branch 5 flows through the air inlet channel 31 and continuously accumulates in the upper chamber 41, pushing the piston 43 downward, and discharging the compressed air in the lower chamber 42 through the exhaust channel 32 to close the steam shut-off valve 2. The steam is prevented from entering the small steam turbine, and the small steam turbine is shut down.

[0038] When the push rod type mechanical shut-off valve 11 fails and cannot be started normally, the control air source can be manually cut off through the manual emergency stop button valve 12 so that it cannot act on the air control valve 3.

[0039] When maintenance is required, the electromagnetic reversing valve 6 can be switched to the energized state by controlling the switch of the stop valve 7, and the power gas source is discharged through the electromagnetic reversing valve 6, so as to facilitate the segmented maintenance of the entire system and quickly find the maintenance point.

[0040] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A small steam turbine pneumatic emergency trip automatic protection system, comprising compressed air, an emergency trip system (1), and a steam shut-off valve (2) connected to the emergency trip system (1); characterized in that: An air control valve (3) and a cylinder (4) are provided between the emergency shutoff system (1) and the steam shutoff valve (2); the output end of the emergency shutoff system (1) is connected to the air control valve (3), and the air control valve (3) is connected to the cylinder (4); the input end of the emergency shutoff system (1) is provided with a branch (5), the output end of the branch (5) is connected to the air inlet passage (31) of the air control valve (3), and the compressed air flowing through the branch (5) enters the cylinder (4) through the air control valve (3); the emergency shutoff system (1) controls the switching of the gas flow direction in the air control valve (3) and the cylinder (4) through the compressed air it delivers, so as to control the steam shutoff valve (2) connected to the cylinder (4) to be opened or closed.

2. A small steam turbine pneumatic emergency trip automatic protection system according to claim 1, characterized in that: A piston (43) is provided in the cylinder (4) and is slidably connected thereto; an upper chamber (41) of the cylinder (4) is located above the piston (43) and a lower chamber (42) of the cylinder (4) is located below the piston (43); a spring (44) is fixedly connected to the top of the piston (43); the other end of the spring (44) is fixedly connected to the top of the cylinder (4); and the bottom of the piston (43) is fixedly connected to the steam shut-off valve (2) via a rod (45).

3. A small steam turbine pneumatic emergency trip automatic protection system according to claim 2, characterized in that: When the compressed air delivered by the emergency shutoff system (1) acts on the air control valve (3), the air inlet passage (31) is connected to the lower chamber (42), and the air outlet passage (32) is connected to the upper chamber (41); the compressed gas delivered by the branch (5) enters the lower chamber (42) via the air inlet passage (31), and the gas in the upper chamber (41) is discharged via the air outlet passage (32).

4. A small steam turbine pneumatic emergency trip automatic protection system according to claim 2, characterized in that: When the emergency shut-off system (1) does not deliver compressed air, the air inlet passage (31) is in communication with the upper chamber (41), and the air outlet passage (32) is in communication with the lower chamber (42); the compressed gas delivered by the branch (5) enters the upper chamber (41) via the air inlet passage (31), and the gas in the lower chamber (42) is discharged via the air outlet passage (32).

5. A small steam turbine pneumatic emergency trip automatic protection system according to claim 3 or 4, characterized in that: The emergency shutoff system (1) comprises a push rod type mechanical shutoff valve (11) and a manual emergency stop button valve (12) which are sequentially arranged in series.

6. A small steam turbine pneumatic emergency trip automatic protection system according to claim 5, characterized in that: An input end of the push rod type mechanical shut-off valve (11) is provided with an air filter valve (13), a pressure reducing valve (14), and an oil mist collector (15) in series in sequence; the branch line (5) is disposed between the oil mist collector (15) and the push rod type mechanical shut-off valve (11).

7. A small steam turbine pneumatic emergency trip automatic protection system according to claim 6, characterized in that: The branch (5) is connected in series with an electromagnetic reversing valve (6).

8. A small steam turbine pneumatic emergency trip automatic protection system according to claim 7, characterized in that: A stop valve (7) is connected in series on the input end of the air filter valve (13), the pipeline between the oil mist collector (15) and the electromagnetic reversing valve (6), and the pipeline between the oil mist collector (15) and the push rod type mechanical shut-off valve (11).

9. A small steam turbine pneumatic emergency trip automatic protection system according to claim 8, characterized in that: The output ends of the electromagnetic reversing valve (6), the push rod type mechanical shut-off valve (11), the manual emergency stop button valve (12), and the exhaust passage (32) are all provided with a muffler (8).

10. A small steam turbine pneumatic emergency trip automatic protection system according to claim 9, characterized in that: A one-way shut-off valve (9) is connected in series on the pipeline between the air-controlled valve (3) and the lower chamber (42).

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