Quick-closing pneumatic actuating mechanism for high-exhaust check valve of steam turbine

Abstract

The utility model discloses a quick-closing pneumatic actuating mechanism for a high-emission check valve of a steam turbine, which belongs to the field of steam turbines and comprises a check valve and a pneumatic mechanism for pushing the check valve to be opened and closed. Compared with the prior art, the device has the advantages that the air dispersing assembly for pressure relief is of a pure mechanical structure and does not depend on a circuit and a sensor, and the position of the concave sealing gasket is determined by comparing the air pressure change of the inlet end and the outlet end of the check valve with the elastic force of the reset spring; when the air pressure of the air inlet of the check valve is smaller than the elastic force of the reset spring, the reset spring pushes the concave sealing gasket to seal the air inlet branch opening of the check valve, and the L-shaped ventilation hole and the air blowing opening are opened, so that air below the air cylinder is rapidly exhausted from the L-shaped ventilation hole; the U-shaped sealing gasket can seal the L-shaped ventilation hole, and meanwhile, the air inlet branch opening and the air blowing opening of the check valve are communicated to pressurize the lower layer of the air cylinder, so that the T-shaped push rod moves upwards.

Description

Technical Field

[0001] The utility model relates to the field of steam turbines, in particular to a quick-closing pneumatic actuator for a high-discharge check valve of a steam turbine. Background Art

[0002] A steam turbine is a rotary steam-powered device that converts the thermal energy of steam into mechanical work. It does this by passing high-temperature, high-pressure steam through a fixed nozzle, accelerating it and spraying it onto the blades, causing the rotor equipped with the blades to rotate, thereby performing external work. During the operation of the steam turbine, a high-discharge check valve is usually installed on the exhaust pipe of the steam turbine to prevent the backflow of high-pressure gas due to a malfunction.

[0003] The high-exhaust check valve of the steam turbine is composed of a check valve and a pneumatic mechanism, in which the rapid opening and closing of the check valve is completed by the cylinder of the pneumatic mechanism; a T-shaped push rod passing through the bottom of the cylinder is installed inside the cylinder, and a quick-closing spring is installed between the T-shaped push rod and the top of the cylinder to accelerate the closing of the check valve when the turbine fails. When the output of the steam turbine weakens, the high-pressure gas tightly pressed against the T-shaped push rod of the cylinder will weaken, and the high-pressure gas at the output end will flow back due to the pressure deviation. At this time, the air pressure at the output end is greater than the air pressure at the input end, so that the air pressure on the upper layer of the T-shaped push rod inside the cylinder is greater than the air pressure on the lower layer. With the assistance of the quick-closing spring, the T-shaped push rod is pressed down quickly, so that the T-shaped push rod quickly closes the check valve to prevent gas backflow.

[0004] During the closing process, in order not to affect the air pressure stability connected to the inlet end of the check valve, a pressure relief valve is usually installed between the air port and the inlet branch of the check valve. The current pressure relief valve is usually a reversing solenoid valve. Although the reversing solenoid valve can effectively relieve the pressure of the gas in the cylinder, its triggering condition depends on whether the reversing solenoid valve can receive the corresponding fault signal. Once the fault is not detected in time (air pressure sensor failure), the gas exhaust channel cannot be switched in time, resulting in local air pressure reflux and damage to the exhaust pipeline. Utility Model Content

[0005] The technical problem to be solved by the utility model is that the exhaust gas discharge of the existing steam turbine high-exhaust check valve quick-closing pneumatic actuator depends on the ventilation solenoid valve. When the ventilation solenoid valve is powered off or the ventilation solenoid valve sensor fails, the gas path cannot be switched normally.

[0006] In order to solve the above technical problems, the technical solution provided by the utility model is: a steam turbine high-exhaust check valve quick-closing pneumatic actuator, including a check valve and a pneumatic mechanism for pushing the check valve to open or close, the pneumatic mechanism including a cylinder located on one side of the check valve, a T-shaped push rod with a thin cylindrical end passing through the bottom surface of the cylinder, and a quick-closing spring located above the thick cylindrical surface of the T-shaped push rod.

[0007] The upper and lower end surfaces of the cylinder are provided with a countercurrent air port and a blowing port connecting the check valve outlet branch and the check valve inlet branch, which are characterized in that: an air dispersion component for dispersing the exhaust gas inside the cylinder is provided between the countercurrent air port and the check valve outlet branch, and between the blowing port and the check valve inlet branch, and the air dispersion component includes a three-way interface connecting the countercurrent air port and the check valve outlet branch, and the blowing port and the check valve inlet branch, a concave sealing gasket passing through a through hole on one side of the three-way interface and the right-angle end of the three-way interface, a T-shaped support rod with a thin column end inserted into the cavity of the concave sealing gasket, and a reset spring sleeved on the outside of the thin column end of the T-shaped support rod, and an L-shaped air exchange hole is provided inside the T-shaped support rod with an open end facing the right-angle through hole end of the three-way interface.

[0008] As an improvement, the concave sealing gasket is made of rubber, and the side wall of the cavity of the concave sealing gasket covers the L-shaped ventilation hole. The thick column end of the T-shaped support rod is connected to the inner wall of the three-way interface by welding. The countercurrent air port and the L-shaped ventilation hole of the three-way interface and the concave sealing gasket closed interface of the check valve outlet branch and the three-way interface are all connected through a high-pressure air pipe.

[0009] As an improvement, the check valve includes a three-way housing and a valve plate located obliquely inside the three-way housing. The valve plate is fixed to the axis by a group of connecting rods passing through both sides of the three-way housing, and the connecting end of the connecting rod and the valve plate is a polygonal connecting column. The three-way housing is connected to the connecting rod through a sealed bearing, and a closing plate fixedly connected by bolts is provided on the top surface of the connecting rod through the through hole of the three-way housing.

[0010] As an improvement, the thin column end of the T-shaped push rod on the bottom surface of the cylinder passes through the inclined port of the three-way housing, and the bottom surface of the cylinder is provided with a sealing frame that seals the inclined port of the three-way housing through bolts.

[0011] As an improvement, the thin column end of the T-shaped push rod passes through the sealing plate on the bottom surface of the sealing frame, and the interior of the sealing plate is provided with a plurality of packing sealing washers sleeved on the thin column end of the T-shaped push rod.

[0012] As an improvement, the top cover plate of the cylinder is a detachable structure connected to the cylinder body by welding.

[0013] The advantages of the present invention over the prior art are that: the device sets the air dispersion component for pressure relief as a purely mechanical structure, which does not rely on circuits and sensors, and determines the position of the concave sealing gasket by comparing the air pressure changes at the inlet and outlet ends of the check valve with the elastic force of the reset spring. When the air pressure at the air inlet of the check valve is less than the elastic force of the reset spring, the reset spring pushes the concave sealing gasket to seal the air inlet branch of the check valve, opens the L-shaped air exchange hole and the air blow port, and allows the gas below the cylinder to be quickly discharged from the L-shaped air exchange hole. When the air pressure at the air inlet of the check valve is greater than the elastic force of the reset spring, the concave sealing gasket will seal the L-shaped air exchange hole while connecting the air inlet branch of the check valve and the air blow port, thereby pressurizing the lower layer of the cylinder, thereby causing the T-shaped push rod to move upward. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The utility model is a general structural diagram of a quick-closing pneumatic actuator for a high-exhaust check valve of a steam turbine.

[0015] Figure 2 The utility model is a cross-sectional view of the overall structure of a quick-closing pneumatic actuator for a high-exhaust check valve of a steam turbine.

[0016] Figure 3 This is an exploded view of a check valve with a quick-closing pneumatic actuator for a high-exhaust check valve of a steam turbine according to the utility model.

[0017] Figure 4 This is an exploded view of the gas dispersion component of a quick-closing pneumatic actuator for a steam turbine high-exhaust check valve of the utility model.

[0018] As shown in the figure: 1. Check valve; 11. Three-way housing; 12. Valve plate; 13. Connecting rod; 14. Closing plate; 2. Pneumatic mechanism; 21. Cylinder; 211. Backflow air port; 212. Blowing port; 22. T-shaped push rod; 23. Quick-closing spring; 24. Sealing frame; 241. Packing sealing gasket; 3. Gas dispersion component; 31. Three-way interface; 32. Concave sealing gasket; 33. T-shaped support rod; 331. L-shaped ventilation hole; 34. Return spring. DETAILED DESCRIPTION

[0019] The present invention will be described in further detail below with reference to the accompanying drawings.

[0020] As the instruction manual Figure 1 、 2As shown, it includes a check valve 1 and a pneumatic mechanism 2 that pushes the check valve 1 to open and close. The pneumatic mechanism 2 includes a cylinder 21 located on one side of the check valve 1, a T-shaped push rod 22 with a thin cylindrical end passing through the bottom surface of the cylinder 21, and a quick-closing spring 23 located above the thick cylindrical surface of the T-shaped push rod 22. The upper and lower end surfaces of the cylinder 21 are provided with a backflow air port 211 and a blow port 212 connecting the air outlet branch of the check valve 1 and the air inlet branch of the check valve 1. The top cover plate of the cylinder 21 is a detachable structure connected to the cylinder 21 body by welding. The top cover plate of the cylinder 21 is a detachable body. After the T-shaped push rod 22 and the quick-closing spring 23 are placed into the cylinder body of the cylinder 21 in sequence, they are welded into an integral cylinder 21 structure using an electric welder. Before welding, pay attention to facing the air inlet end of the backflow air port 211 in the direction of the air outlet branch of the check valve 1, that is, the direction of the backflow air port 211 and the air blowing port 212 are opposite, and a sealing ring is installed below the air blowing port 212 between the thin column end of the T-shaped push rod 22 and the through hole on the bottom surface of the cylinder 21 to prevent gas leakage.

[0021] As the instruction manual Figure 1 、 2 As shown in Figure 3, the check valve 1 includes a three-way housing 11 and a valve plate 12 located obliquely inside the three-way housing 11. The valve plate 12 is fixed to the axis by a group of connecting rods 13 passing through both sides of the three-way housing 11, and the connecting ends of the connecting rods 13 and the valve plate 12 are polygonal connecting columns. The three-way housing 11 is connected to the connecting rod 13 through a sealed bearing, and a closing plate 14 fixedly connected by bolts is provided on the top surface of the through-hole of the connecting rod 13 of the three-way housing 11. The valve plate 12 is placed into the inclined surface port of the three-way housing 11. A rotating fixing rod is provided above the valve plate 12. One side of the polygonal connecting column of the two connecting rods 13 is inserted into the interior of the fixing rod of the valve plate 12 from the two opposite side through-holes of the three-way housing 11. The polygonal through-hole allows the valve plate 12 to rotate synchronously around the connecting rod 13, and the inner wall of the air inlet of the three-way housing 11 is provided with an inclined closed opening for fixing the bottom surface of the valve plate 12 to limit the rotation direction of the valve plate 12 (a sealing ring is provided on the outer wall of the valve plate 12 to prevent the exhaust gas from flowing back). In order to ensure the normal operation of the connecting rod 13, a sealed bearing is provided on the cylindrical end of the connecting rod 13 to seal it while ensuring the lubrication of the connecting rod 13 during rotation. The sealed bearing body is inserted into the bearing through-hole on the outer wall of the three-way housing 11 (the through-holes of the connecting rod 13 on both sides of the three-way housing 11 are T-shaped holes, and the closing plate 14 is then bolted to the outlet end of the sealed bearing for sealing).

[0022] The thin column end of the T-shaped push rod 22 on the bottom surface of the cylinder 21 passes through the inclined port of the three-way housing 11, and the bottom surface of the cylinder 21 is provided with a sealing frame 24 that seals the inclined port of the three-way housing 11 through bolts, and the thin column end of the T-shaped push rod 22 passes through the sealing plate on the bottom surface of the sealing frame 24, and the interior of the sealing plate is provided with a plurality of packing sealing washers 241 that are sleeved on the thin column end of the T-shaped push rod 22; the inclined port of the three-way housing 11 is opposite to the upper surface of the valve plate 12, so that the thin column end of the T-shaped push rod 22 can be directly connected to the upper surface of the valve plate 12 when it is pushed, so as to push the valve plate 12 to seal the inclined closed port of the inner wall of the air inlet of the three-way housing 11, and The bottom surface of the cylinder 21 is welded with a sealing frame 24 using an electric welder, and the bottom surface of the sealing frame 24 has a sealing plate that seals the inclined port of the three-way housing 11, so that the cylinder 21 can be fixed to the inclined port of the three-way housing 11 through the sealing plate on the bottom surface of the sealing frame 24. In order to facilitate disassembly, bolt connection is generally adopted; in order to ensure that the thin column end of the T-shaped push rod 22 can still be sealed after passing through the sealing plate on the bottom surface of the sealing frame 24 while ensuring its reciprocating motion characteristics, a multi-layer packing sealing gasket 241 is usually installed on the sealing plate on the bottom surface of the sealing frame 24 for sealing, so as to avoid air leakage when the T-shaped support rod 33 moves back and forth.

[0023] As the instruction manual Figure 1 、 2As shown in Figure 4, a gas dispersion component 3 for dispersing the exhaust gas inside the cylinder 21 is provided between the backflow air port 211 and the air outlet branch of the check valve 1, as well as between the air blowing port 212 and the air inlet branch of the check valve 1. The gas dispersion component 3 includes a three-way interface 31 connecting the backflow air port 211 and the air outlet branch of the check valve 1, as well as the air blowing port 212 and the air inlet branch of the check valve 1, a concave sealing gasket 32 ​​passing through a through hole on one side of the three-way interface 31 and a right-angled end of the three-way interface 31, a T-shaped support rod 33 with a thin column end inserted into the cavity of the concave sealing gasket 32, and a return spring 34 sleeved on the outside of the thin column end of the T-shaped support rod 33. The interior of the T-shaped support rod 33 is provided with an L-shaped ventilation hole 331 with an open end facing the right-angled through-hole end of the three-way interface 31. The concave sealing gasket 32 ​​is made of rubber, and the side wall of the cavity of the concave sealing gasket 32 ​​covers the L-shaped ventilation hole 331. The thick column end of the T-shaped support rod 33 is connected to the inner wall of the three-way interface 31 by welding. The interface facing the L-shaped ventilation hole 331 of the counterflow air port 211 and the three-way interface 31 and the closed interface of the concave sealing gasket 32 ​​of the three-way interface 31 are all connected through a high-pressure air pipe. The reset spring 34 is sleeved on the T-shaped support rod 33. The t-shaped support rod 33 is inserted into the parallel side interface of the three-way interface 31. Note that the vertical air port of the L-shaped ventilation hole 331 is facing the vertical interface direction of the three-way interface 31 (the cavity length of the concave sealing gasket 32 ​​is greater than the distance between the vertical air port of the L-shaped ventilation hole 331 and the top of the thin column of the T-shaped support rod 33, ensuring that the concave sealing gasket 32 ​​can completely block the vertical air port of the L-shaped ventilation hole 331 when pressed down, and under normal circumstances, the concave sealing gasket 32 ​​is in the reset spring Under the thrust of 34, while blocking the interface at the other end in the parallel direction of the three-way interface 31, the vertical air port of the L-shaped ventilation hole 331 is leaked, so that the vertical air port of the L-shaped ventilation hole 331 is connected to the vertical interface of the three-way interface 31). In order to seal the three-way interface 31 and the thick column end of the T-shaped support rod 33, an electric welder is used to weld the two. When connecting, the vertical interface of the three-way interface 31 is connected to the countercurrent air port 211 or the blowing port 212 using a high-pressure air pipe, and the opposite interface of the air dispersing component 3 of the three-way interface 31 is connected to the outlet branch of the check valve 1 or the inlet branch of the check valve 1 using a high-pressure air pipe.

[0024] When the utility model is implemented, when the turbine fails, the input gas is weakened, and the gas at its output end flows back, the gas entering the outlet branch of the check valve 1 will squeeze the concave sealing gasket 32 ​​downward, so that the concave sealing gasket 32 ​​seals the vertical air port of the L-shaped air exchange hole 331 while ensuring that the return gas enters the top of the cylinder 21. Under the dual action of the quick-closing spring 23 and the return air pressure, the T-shaped push rod 22 is pushed downward, and the valve plate 12 is quickly closed under the push of the T-shaped push rod 22; when the T-shaped push rod 22 moves downward and squeezes, the concave sealing gasket 32 ​​is reset under the thrust of the reset spring 34 due to the weakening of the input gas, and the air inlet branch of the check valve 1 is re-sealed, so that the T-shaped The high-pressure gas below the push rod 22 flows back from the blowing port 212 into the vertical end of the L-shaped ventilation hole 331, and is then discharged from the outlet end of the L-shaped ventilation hole 331, ensuring that the squeezed gas will not flow back into the air inlet of the check valve 1; similarly, when intake, the quick-closing spring 23 is squeezed and retracted upward under the push of the input gas, and the thin column end of the T-shaped push rod 22 is separated from the valve plate 12, ensuring that the valve plate 12 can be pushed normally by the input gas, thereby connecting the input port and output port of the check valve 1; while the thin column end of the T-shaped push rod 22 moves upward, the gas above the cylinder 21 will enter the vertical end of the L-shaped ventilation hole 331 of the air dispersing component 3 at this end from the counterflow air port 211, and then be discharged from the outlet end of the L-shaped ventilation hole 331.

[0025] The above description of the present invention and its embodiments is non-limiting. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. In short, if a person skilled in the art is inspired by the above, and does not deviate from the purpose of the present invention, without inventive design, a structure and embodiment similar to the technical solution should fall within the scope of protection of the present invention.

Claims

1. A pneumatic actuator for a quick-closing check valve of a steam turbine high-exhaust gas flow, comprising a check valve (1) and a pneumatic mechanism (2) for pushing the check valve (1) to open or close, wherein the pneumatic mechanism (2) comprises a cylinder (21) located on one side of the check valve (1), a T-shaped push rod (22) with a thin cylindrical end passing through the bottom surface of the cylinder (21), and a quick-closing spring (23) located above the thick cylindrical surface of the T-shaped push rod (22); The upper and lower end surfaces of the cylinder (21) are provided with a reverse flow air port (211) and an air blowing port (212) connected to the air outlet branch of the check valve (1) and the air inlet branch of the check valve (1), characterized in that: A gas dispersion component (3) for dispersing waste gas inside the cylinder (21) is provided between the reverse flow air port (211) and the air outlet branch of the check valve (1), as well as between the air blowing port (212) and the air inlet branch of the check valve (1). The gas dispersion component (3) comprises a three-way interface (31) connecting the reverse flow air port (211) and the air outlet branch of the check valve (1), as well as the air blowing port (212) and the air inlet branch of the check valve (1), a concave sealing gasket (32) passing through a through hole on one side of the three-way interface (31) and a right-angle end of the three-way interface (31), a T-shaped support rod (33) with a thin column end inserted into the cavity of the concave sealing gasket (32), and a return spring (34) sleeved on the outside of the thin column end of the T-shaped support rod (33). An L-shaped air exchange hole (331) is provided inside the T-shaped support rod (33) with an open end facing the right-angle through hole end of the three-way interface (31).

2. A steam turbine high-pressure exhaust check valve quick-closing pneumatic actuator according to claim 1, characterized in that: The concave sealing gasket (32) is made of rubber, and the side wall of the cavity of the concave sealing gasket (32) covers the L-shaped ventilation hole (331). The thick column end of the T-shaped support rod (33) is connected to the inner wall of the three-way interface (31) by welding. The reverse flow air port (211) and the L-shaped ventilation hole (331) of the three-way interface (31) are connected to the interface, and the outlet branch of the check valve (1) and the closed interface of the concave sealing gasket (32) of the three-way interface (31) are all connected through a high-pressure air pipe.

3. The pneumatic actuator for quick closing of a high-pressure exhaust check valve of a steam turbine according to claim 1, characterized in that: The check valve (1) comprises a three-way housing (11) and a valve plate (12) located obliquely inside the three-way housing (11); the valve plate (12) is fixed to an axis by a group of connecting rods (13) passing through both sides of the three-way housing (11); and the connecting ends of the connecting rods (13) and the valve plate (12) are polygonal connecting columns; the three-way housing (11) is connected to the connecting rods (13) through a sealing bearing, and a closing plate (14) fixedly connected by bolts is provided on the top surface of the through-hole of the connecting rod (13) of the three-way housing (11).

4. The pneumatic actuator for quick closing of a high-pressure exhaust check valve of a steam turbine according to claim 1, characterized in that: The thin column end of the T-shaped push rod (22) on the bottom surface of the cylinder (21) passes through the inclined surface port of the three-way housing (11), and the bottom surface of the cylinder (21) is provided with a sealing frame (24) that seals the inclined surface port of the three-way housing (11) through bolts.

5. The pneumatic actuator for quick closing of a high-pressure exhaust check valve of a steam turbine according to claim 4, characterized in that: The thin column end of the T-shaped push rod (22) passes through the sealing plate on the bottom surface of the sealing frame (24), and the interior of the sealing plate is provided with a plurality of packing sealing washers (241) sleeved on the thin column end of the T-shaped push rod (22).

6. The pneumatic actuator for quick closing of a high-pressure exhaust check valve of a steam turbine according to claim 1, characterized in that: The top cover plate of the cylinder (21) is a detachable structure connected to the cylinder (21) body by welding.

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