Hydraulic turbine governor air supplementing device and air supplementing method

Abstract

The application relates to a water turbine governor air supplement device and an air supplement method. The device comprises a first-stage air supplement unit and a second-stage air supplement unit. The first-stage air supplement unit comprises a first valve and a pressure-sensitive execution element, the pressure-sensitive execution element is in communication with the inside of a pressure tank, and drives the first valve to open and close according to the pressure in the pressure tank. The second-stage air supplement unit comprises a second valve and a liquid level sensing element, the air inlet of the second valve is in communication with the air outlet of the first valve, the air outlet of the second valve is in communication with the inside of the pressure tank, and the liquid level sensing element is used for sensing the liquid level in the pressure tank and unlocking the second valve when the liquid level exceeds a preset threshold. The air supplement method is realized based on the water turbine governor air supplement device. The water turbine governor air supplement device and the air supplement method can automatically complete the air supplement operation according to two parameters of pressure and liquid level, maintain the pressure and oil level of the pressure tank in a normal range, and can avoid the safety risks caused by manual operation.

Description

Technical Field

[0001] This invention relates to the field of water turbine speed control equipment technology, and in particular to a water turbine speed governor air supply device and air supply method. Background Technology

[0002] The turbine speed control system of a giant hydroelectric power station controls the opening and closing of guide vanes by using pressure energy stored in pressure oil tanks, thereby regulating the start-up, shutdown, and power output of the unit. Pressure oil tanks typically store compressed air and turbine oil, and the oil-air ratio needs to be maintained within a certain range to ensure the system has sufficient pressure energy reserves and operational stability.

[0003] Because it's impossible to completely eliminate leaks in the pipes, valves, and isolation valves within the speed control system, internal leakage of pressurized oil into the return oil tank or external gas leakage can occur. When internal leakage causes a pressure drop, the pressure pump will automatically start to replenish oil and pressurize, potentially leading to excessive replenishment and a rise in the pressure oil tank level. An excessively high level means the gas chamber volume is compressed, resulting in insufficient air pressure reserve and affecting system safety. Furthermore, small fluctuations in unit load consuming a small amount of oil can also cause a pressure drop.

[0004] To address the issue of excessively high oil levels in pressure tanks, manual oil draining and gas replenishment is typically employed. This involves workers manually opening the drain valve at the bottom of the pressure tank and simultaneously activating the manual gas replenishment valve to restore the normal oil-gas ratio. However, this current method presents the following technical problems: operating the high-pressure drain valve during unit operation poses a safety risk of injury from high-pressure oil splashing; the operation relies on manual judgment and control, making automated control impossible, and the adjustment process is difficult to achieve linear and stable operation. Summary of the Invention

[0005] To address the technical problem in the prior art that the pressure oil tank of a giant turbine governor is difficult to automatically and linearly replenish pressure during the operation of a turbine unit, this invention provides a turbine governor air replenishment device and air replenishment method.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A turbine governor air supply device includes a first-stage air supply unit and a second-stage air supply unit; the first-stage air supply unit and the second-stage air supply unit are connected in series between an air source and a pressure oil tank of a giant turbine governor. The first-stage air replenishment unit includes a first valve and a pressure sensing actuator. The pressure sensing actuator is connected to the inside of the pressure tank and drives the first valve to open and close according to the pressure inside the pressure tank. The second-stage air replenishment unit includes a second valve and a liquid level sensor. The air inlet of the second valve is connected to the air outlet of the first valve, and the air outlet of the second valve is connected to the inside of the pressure oil tank. The liquid level sensor is used to sense the liquid level in the pressure oil tank and releases the lock on the second valve when the liquid level exceeds a preset threshold.

[0008] Furthermore, the pressure-sensing actuator includes: a spiral Bourdon tube; The pressure acquisition end of the outer ring of the spiral Bourdon tube is connected to the inner cavity of the pressure tank, and the free end of the inner ring of the spiral Bourdon tube is connected to the operating rod of the first valve. When the pressure in the pressure tank changes, the Bourdon tube deforms and drives the operating rod of the first valve to rotate through the transmission mechanism to open and close it.

[0009] Furthermore, the pressure-sensing actuator also includes: a central gear and a sector gear; The first valve is configured as a ball valve; The central gear is rotatably mounted on the inner wall of the Bourdon tube housing, and the rotation direction of the central gear is consistent with the adjustment direction of the operating rod of the first valve; The sector gear is rotatably mounted on the inner wall of the Bourdon tube housing. The free end of the inner ring of the Bourdon tube is connected to the sector gear, and the sector gear meshes with the central gear. The end face of the central gear is perpendicular to the operating rod of the first valve, and the center of the central gear is fixedly connected to the operating rod of the first valve.

[0010] Furthermore, the second valve includes: a valve body, a locking rod, a valve stem, a valve disc, a sealing ring, and a float in the flapper level gauge; The valve body is provided with a first chamber for installing the locking rod, a second chamber for installing the valve stem, and a third chamber for installing on the valve disc; The first chamber is configured as an inclined structure with different heights at both ends; the locking rod is configured as a magnetic gravity rod, which is installed in the first chamber and slides between the two ends of the first chamber; The second chamber is configured as an inclined structure with different heights at both ends, and the upper end of the second chamber is connected to the lower end of the first chamber; the valve stem is located in the second chamber, with the upper end of the valve stem perpendicular to the locking rod, and the valve stem slides between the two ends of the second chamber; The third chamber is horizontally positioned, and the valve disc is inclinedly positioned within the third chamber. A sealing ring is inclinedly positioned within the third chamber and connected to the inner wall of the third chamber. The valve disc moves within the third chamber, engaging with the sealing ring to connect or block the two ends of the third chamber. The upper end of the valve disc is fixedly connected to the lower end of the valve stem. The end of the third chamber corresponding to the lower end of the valve disc is configured as an air inlet for connecting to the air outlet of the first valve. The end of the third chamber corresponding to the upper end of the valve disc is configured as an exhaust outlet for connecting to the upper end of the inner cavity of the pressure tank. The level sensing element is set as the float in the flap level gauge. The float has a built-in magnetic ring, and the magnetic poles of the locking rod and the magnetic ring are the same at the opposite end. The second valve is installed at the flap level gauge of the pressure oil tank, and its installation height is the upper limit of the normal oil level of the pressure oil tank. When the float moves away from the locking rod, the locking rod slides down to the lower end of the first chamber under its own weight and locks the valve stem. When the float moves closer to the locking rod, the locking rod slides to the upper end of the first chamber under the action of repulsive magnetic force to release the lock on the valve stem.

[0011] Furthermore, it also includes: springs; The middle position of the second chamber is set as an enlarged cylindrical chamber; A circular baffle is fixed on the valve stem, and the valve stem passes through the center of the circular baffle and is fixedly connected to it; A circular baffle is installed inside a cylindrical cavity; a spring is sleeved on the valve stem and is also installed inside the cylindrical cavity; the upper end of the cylindrical cavity limits the upper end of the spring, and the upper end of the circular baffle limits the lower end of the spring.

[0012] Furthermore, the first-stage air replenishment unit also includes: a fixed assembly; The pressure-sensing actuator is fixed to the upper end of the pressure tank by a fixing assembly.

[0013] Furthermore, the sealing ring is a rubber sealing ring.

[0014] This invention also provides a method for replenishing air to a giant turbine governor. This method is based on a turbine governor air replenishment device and includes the following steps: Step 1. Obtain the current pressure inside the pressure tank; Step 2. When the current pressure is lower than the preset first pressure threshold, the pressure sensing actuator drives the first valve to open to replenish gas into the pressure tank, and the opening degree of the first valve is negatively correlated with the current pressure. Step 3. Obtain the current liquid level in the pressure tank; Step 4. When the current liquid level exceeds the preset first liquid level threshold, the liquid level sensor drives the locking rod to release the lock on the second valve; Step 5. With the first valve open and the second valve unlocked, the gas passes through the first valve and the second valve in sequence and enters the pressure oil tank. Step 6. When the current pressure rises to the preset second pressure threshold, the pressure sensing actuator drives the first valve to close; Step 7. When the current pressure is lower than the first pressure threshold and the current liquid level is lower than the first liquid level threshold, the locking lever remains locked to the second valve, and the second valve remains closed. Step 8. After the first valve is closed, the air supply pressure at the front end of the second valve disappears, and the second valve automatically closes under its own weight of its stem and disc. Step 9. When the current liquid level drops from above the first liquid level threshold to below the first liquid level threshold, the liquid level sensor releases the driving force on the locking rod, and the locking rod automatically resumes locking the second valve by its own weight.

[0015] The present invention also provides a turbine speed regulation system, including a pressure oil tank and a turbine governor air supply device; the air supply device is connected to the pressure oil tank and is used to automatically maintain the pressure and liquid level in the pressure oil tank.

[0016] Furthermore, the volume ratio of turbine oil to compressed air in the pressure tank is 1:2.

[0017] The air supply device and method for a water turbine governor provided by this invention have the following beneficial effects: The turbine governor air replenishment device and method provided by this invention connects a first-stage air replenishment unit and a second-stage air replenishment unit in series between the air source and the pressure oil tank. A pressure-sensing actuator automatically controls the opening and closing of the first valve based on the pressure in the pressure oil tank, achieving linear regulation of the air replenishment flow. Simultaneously, a liquid level sensor controls the locking or unlocking of the second valve based on the liquid level in the pressure oil tank, allowing gas to enter the pressure oil tank only when the liquid level exceeds a preset threshold. This turbine governor air replenishment device and method employs a purely mechanical structure, requiring no external power supply or control program. It can automatically complete the air replenishment operation based on two parameters: pressure and liquid level, maintaining the pressure and oil level in the pressure oil tank within the normal range, thus avoiding the safety risks associated with manual operation. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the air supply device for a water turbine governor provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the pressure-sensing actuator structure provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the second valve in closed state provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the second valve in the conducting state provided in an embodiment of the present invention.

[0019] Among them, 1-pressure oil tank, 2-pressure sensing actuator, 3-first valve, 4-second valve, 5-float, 21-inner wall, 22-spiral Bourdon tube, 23-center gear, 24-sector gear, 41-valve body, 42-first chamber, 43-locking rod, 44-second chamber, 45-valve stem, 46-third chamber, 47-valve disc, 48-spring, 49-sealing ring. Detailed Implementation

[0020] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the invention will be thorough and complete.

[0021] See Figure 1 This invention provides a turbine governor air supply device, including a first-stage air supply unit and a second-stage air supply unit, which are connected in series between an air source and a pressure tank 1 via pipelines. The air source can be a power plant compressed air system, with a pressure higher than the maximum working pressure of the pressure tank 1 by a certain value, to ensure that the gas can overcome the internal pressure of the tank and enter smoothly during air supply. The first-stage air supply unit linearly adjusts the air supply flow rate according to the pressure in the pressure tank 1, and the second-stage air supply unit determines whether to allow the air supply gas to enter the pressure tank 1 based on the liquid level in the pressure tank 1. The air supply circuit can only be activated after both the first-stage and second-stage air supply units meet the trigger conditions, realizing an automatic air supply control logic with liquid level safety interlock.

[0022] The first-stage air supply unit includes a first valve 3 and a pressure-sensing actuator 2. The first valve 3 adopts a standard ball valve structure, with a through hole matching the pipe diameter on its valve core ball, and an operating rod for controlling its on / off state. The nominal diameter of the first valve 3 is determined according to the volume of the pressure tank 1 and the air supply rate requirements. For giant water turbines, a ball valve of appropriate specifications can be used.

[0023] See Figure 1 and Figure 2 The pressure-sensing actuator 2 includes a spiral Bourdon tube 22, whose outer pressure acquisition end is connected to the inside of the pressure tank 1 via a pipeline. A shut-off valve can be installed on the pipeline for maintenance isolation. The free end of the inner coil of the Bourdon tube outputs deformation displacement. The Bourdon tube is made of a metal material with good elasticity, and its spiral number is designed according to the required sensitivity. For the working pressure range of the pressure tank 1, the Bourdon tube is designed to generate an appropriate free end angular displacement under full-scale differential pressure, which, after being amplified by the transmission mechanism, is sufficient to drive the ball valve from fully closed to fully open.

[0024] In some feasible implementations, for low-pressure or high-pressure applications, a diaphragm-type pressure sensing element can be used instead of the spiral Bourdon tube 22. The diaphragm is formed by welding two circular metal diaphragms together, and is either evacuated or filled with a reference pressure. When the external pressure changes, the center of the diaphragm is displaced, driving the sector gear 24 via a connecting rod. The diaphragm-type sensing element has a large displacement and good vibration resistance, making it suitable for environments with high vibration, but its linearity is slightly poor, requiring compensation through a cam mechanism.

[0025] In some feasible implementations, see Figure 1 and Figure 2 The pressure-sensing actuator 2 also includes a sector gear 24 and a central gear 23. The sector gear 24 is rotatably mounted on the inner wall 21 of the Bourdon tube housing, and the free end of the inner ring of the Bourdon tube is fixedly connected to the sector gear 24. The central gear 23 is rotatably mounted on the inner wall 21 of the Bourdon tube housing, and its rotation axis coincides with the axis of the operating rod of the first valve 3. The end face of the central gear 23 is perpendicular to the operating rod, and a square hole is provided in the center, which tightly engages with the square shaft head at the top of the operating rod to transmit torque. The sector gear 24 meshes with the central gear 23, and the transmission ratio is designed to amplify the deformation angle of the Bourdon tube, ensuring that the ball valve obtains sufficient rotational stroke. The gear transmission has a reverse self-locking characteristic, so the ball valve will not swing due to gas flow disturbances when the pressure is stable.

[0026] In some feasible implementations, the meshing transmission between the sector gear 24 and the central gear 23 can be replaced by a shift fork mechanism. The free end of the Bourdon tube is directly connected to the shift fork, and the other end of the shift fork is inserted into a groove on the ball valve operating rod. The deformation of the Bourdon tube directly drives the shift fork to rotate the ball valve. This structure is simpler, but the transmission ratio is fixed and the friction is relatively large, making it suitable for applications where high precision is not required.

[0027] When the pressure in pressure tank 1 decreases, the Bourdon tube contracts, driving the sector gear 24 to rotate, which in turn drives the central gear 23 and the operating lever of the first valve 3 to rotate counterclockwise, opening the ball valve. The greater the pressure drop, the greater the contraction amplitude, the larger the ball valve opening, and the greater the air supply flow. When the pressure increases, the Bourdon tube expands, driving the ball valve to rotate clockwise to partially or completely close. This structure utilizes the pressure and deformation characteristics of the Bourdon tube to directly convert the pressure signal into the valve rotation angle, achieving linear matching between the air supply flow and pressure deviation. It requires no electrical sensors or controllers and offers rapid response. The Bourdon tube has low elastic hysteresis, maintaining high accuracy over long-term use.

[0028] See Figure 1 The first-stage air supply unit can be installed on the upper part of the pressure oil tank 1 using a fixing assembly. Specifically, multiple nuts are provided on the top of the pressure oil tank 1, and corresponding through holes are provided on the bottom of the Bourdon tube housing. The housing height is adjusted and fixed by screws and nuts, so that the square hole of the central gear 23 and the square shaft head of the operating rod are accurately fitted. This installation method allows for on-site adjustment to accommodate the height differences of the operating rods of different ball valve models. In addition to being fixed to the top of the pressure oil tank 1, the first-stage air supply unit can also be fixed to the side wall of the pressure oil tank 1 via a bracket and communicate with the inside of the pressure oil tank 1 via a capillary tube. This method avoids opening a hole at the top, but increases the number of pipe connections and leakage points. The top direct installation scheme provided by this embodiment of the invention is simpler.

[0029] In some feasible implementations, see Figure 1The second-stage air replenishment unit includes a second valve 4 and a float 5 in the flapper level gauge. The second valve 4 is installed at the flapper level gauge of the pressure tank 1, with the installation height corresponding to the upper limit of the normal oil level in the pressure tank 1. For the pressure tank 1 of a giant turbine, the upper limit of the oil level is usually set at 2 / 3 of the total height of the tank. Installing the second valve 4 at this height ensures that air replenishment is only permitted when the oil level exceeds the normal upper limit.

[0030] See Figure 1 , Figure 3 and Figure 4 The valve body 41 of the second valve 4 is machined as a single piece of stainless steel, with precision drilling inside to form three chambers. The first chamber 42 is designed with an inclined structure that is lower on the left and higher on the right, with an appropriate inclination angle. The cross-section of the first chamber 42 is circular or rectangular, with an appropriate inner diameter or side length to ensure that the locking rod 43 can slide freely without jamming.

[0031] The locking rod 43 is a magnetic gravity rod, with its main body made of a stainless steel sleeve. A cylindrical permanent magnet is embedded inside, and the outer end face of the permanent magnet is flush with the right end face of the locking rod 43. The total length of the locking rod 43 is slightly less than the length of the first chamber 42 to ensure complete sliding between its left and right ends. An appropriate gap is maintained between the outer diameter of the locking rod 43 and the inner diameter of the first chamber 42 to reduce frictional resistance. The mass of the locking rod 43 is designed to ensure reliable gravity-based reset.

[0032] The second chamber 44 is designed with an inclined structure, higher at the top and lower at the bottom. The inclination angle is the same as that of the first chamber 42, but the inclination direction is opposite. The upper end of the second chamber 44 is connected to the lower end of the first chamber 42. The second chamber 44 has a circular cross-section with an appropriate inner diameter. The valve stem 45 is located within the second chamber 44, with its upper surface being flat and perpendicular to the axis of the locking rod 43. The valve stem 45 is made of stainless steel, and an appropriate gap is maintained between its outer diameter and the inner diameter of the second chamber 44. The second chamber 44 expands in the middle to form a cylindrical chamber, with a diameter appropriately larger than that of the second chamber 44. A circular baffle is fixed to the valve stem 45, either threaded or integrally formed with it. Its diameter matches the inner diameter of the cylindrical chamber, with an appropriate gap between them. A spring 48 is sleeved on the valve stem 45 and located within the cylindrical chamber. Spring 48 is a compression helical spring made of stainless steel wire, with its wire diameter, mean diameter, free length, and stiffness determined according to the required reset force. The upper end of the cylindrical chamber limits the upper end of spring 48, and the upper end of the circular baffle limits the lower end of spring 48. Spring 48 is pre-compressed during installation, always applying a downward thrust to valve stem 45. This thrust is designed to be slightly greater than the total weight of valve stem 45 and valve disc 47, ensuring reliable valve closure even without air pressure. Spring 48 can also be replaced by a disc spring or wave spring, providing greater elasticity in a smaller space. Eliminating spring 48 and relying solely on the self-resetting of valve stem 45 and valve disc 47 would reduce reset speed and reliability, especially when the valve is installed at an angle. This invention preferably uses a helical compression spring 48 to provide a stable linear reset force.

[0033] The third chamber 46 is horizontally positioned, with its axis perpendicular to the axis of the second chamber 44. The inner wall of the third chamber 46 is machined with a conical sealing surface for mating with the valve disc 47. The valve disc 47 is conical or spherical, with its cone angle or spherical radius matching the sealing surface of the third chamber 46. The valve disc 47 is made of stainless steel and its surface is precision ground. The sealing ring 49 is a rubber sealing ring with an O-shaped or Y-shaped cross-section, made of fluororubber or nitrile rubber. The sealing ring 49 is embedded in an annular groove on the inner wall of the third chamber 46, slightly protruding from the inner wall surface. The rubber sealing ring 49 can be replaced by a metal hard seal, where both the valve disc 47 and the valve body 41 sealing surfaces are made of precision-ground stainless steel, achieving sealing through metal-to-metal contact. Metal hard seals have advantages such as high temperature resistance, corrosion resistance, and long service life, but require higher machining precision. In this embodiment of the invention, based on the operating temperature range of the pressure oil tank 1, the use of the rubber sealing ring 49 meets the requirements and is at a lower cost. The upper end of the valve disc 47 is threaded or welded to the lower end of the valve stem 45. The air inlet of the third chamber 46 is located on one side of the lower end of the valve disc 47 and is connected to a pipe from the first-stage air supply unit via a threaded or compression fitting; the exhaust port is located on one side of the upper end of the valve disc 47 and is connected to the upper end of the inner cavity of the pressure oil tank 1 via a pipe. The effective pressure-bearing area of ​​the lower end face of the valve disc 47 is determined according to the diameter of the air supply pipe and the air pressure thrust requirements.

[0034] The level sensing element is float 5 in the flapper level gauge. Float 5 is a hollow stainless steel float cylinder with a magnetic ring encapsulated inside. The magnetic ring is made of neodymium iron boron, and its magnetic poles are axial. The permanent magnet at the right end of the locking rod 43 is positioned opposite the magnetic ring, and both have the same magnetic poles. Float 5 moves with the rise and fall of the liquid level, and its movement is limited by the guide rod of the flapper level gauge. When the liquid level is below the normal upper limit, float 5 is located at a certain distance below the second valve 4; when the liquid level exceeds the upper limit, float 5 rises to a position level with or slightly higher than the second valve 4. At this time, the distance between float 5 and the right end of the locking rod 43 is shortened to a range sufficient to generate magnetic force to push the locking rod 43.

[0035] This embodiment of the invention employs a gravity locking and magnetic unlocking mechanism. When the liquid level is normal, the float 5 moves away, and the locking rod 43 slides downwards and to the left along the inclined first chamber 42 under the action of gravity to the lowest position on the left. The component of gravity of the locking rod 43 along the inclined plane overcomes the friction between the locking rod 43 and the inner wall 21 of the chamber, allowing the locking rod 43 to reliably slide to the left end. At this time, the left end of the locking rod 43 is directly above the upper end of the valve stem 45, forming a mechanical obstruction. When air pressure acts on the lower end of the valve disc 47, the valve stem 45 is subjected to an upward thrust, which is greater than the sum of the total weight of the valve stem 45, the valve disc 47, and the elastic force of the spring 48. However, due to the obstruction of the locking rod 43, the valve stem 45 cannot move upwards, and the second valve 4 remains locked.

[0036] When the liquid level exceeds the upper limit, float 5 approaches the right end of locking rod 43, and the magnetic ring and permanent magnet generate a repulsive magnetic force. This magnetic force overcomes the gravitational component and friction of locking rod 43, pushing it upward and to the right along the first chamber 42 to its highest position. The left end of locking rod 43 moves away from the upper end of valve stem 45, releasing the upward movement path of valve stem 45 and unlocking the second valve 4. This design utilizes gravity for automatic locking and magnetic force for non-contact unlocking, requiring no external power or seal penetration, adapting to high-pressure oil and gas environments, and automatically switching between locked and unlocked states according to changes in liquid level.

[0037] In some feasible implementations, the magnetic unlocking of the locking rod 43 can be replaced by direct actuation of the mechanical float 5. A push rod extending into the pressure tank 1 is provided on the valve body 41 of the second valve 4. The lower end of the push rod is connected to the float 5, and the upper end contacts the locking rod 43. When the liquid level rises, the float 5 lifts the locking rod 43 by lever or direct actuation. This solution does not require a magnet and is lower in cost, but it requires a mechanical seal to pass through the wall of the pressure tank 1, increasing the risk of leakage. The preferred embodiment of the present invention is a magnetic non-contact solution, which provides better sealing reliability under high pressure.

[0038] See Figures 1-4 The following describes in detail the complete closed-loop working process of the device, from pressure reduction to gas replenishment and then to reset, based on specific operating conditions.

[0039] The first operating condition: pressure below the first pressure threshold, liquid level normal. When the pressure in the pressure tank 1 drops below the preset first pressure threshold, the spiral Bourdon tube 22 in the first-stage air replenishment unit senses the pressure decrease and contracts, driving the first valve 3 to open to the corresponding degree via the sector gear 24 and the central gear 23; the lower the pressure, the larger the opening. Simultaneously, because the liquid level is normal, the float 5 moves away from the locking rod 43, and the locking rod 43 is in the left-end locked position, blocking the valve stem 45. High-pressure gas entering the air inlet of the second valve 4 cannot push open the valve disc 47, blocking the air replenishment channel, and the device does not replenish air. This design avoids blindly replenishing air when the oil level is normal, which could lead to an abnormal rise in the oil level.

[0040] The second operating condition: pressure below the first pressure threshold, liquid level above the normal upper limit. When the pressure in pressure tank 1 drops below the preset first pressure threshold and the liquid level exceeds the normal upper limit, the system enters automatic gas replenishment mode. In the first-stage gas replenishment unit, the spiral Bourdon tube 22 senses the pressure drop and undergoes contraction deformation, driving the first valve 3 to open via the sector gear 24 and the central gear 23. The lower the pressure, the greater the deformation of the Bourdon tube, the greater the opening of the ball valve, and the greater the gas flow. Since the current liquid level is above the normal upper limit, the float 5 in the flap level gauge rises to the high position with the liquid level. The magnetic ring built into the float 5 and the permanent magnet at the right end of the locking rod 43 of the second valve 4 are in a state of same pole opposite each other, and the magnetic repulsion force generated overcomes the gravitational component of the locking rod 43, pushing the locking rod 43 to the high position at the right end of the first chamber 42, releasing the mechanical lock on the valve stem 45. At this time, high-pressure gas from the gas source enters the inlet of the second valve 4 through the opened first valve 3. The upward thrust generated by the gas pressure acting on the lower end face of the valve disc 47 overcomes the weight of the valve stem 45, the valve disc 47 assembly, and the preload force of the spring 48, lifting the valve disc 47 and opening the gas supply channel, allowing gas to enter the gas chamber of the pressure oil tank 1. As gas continues to be supplied, the volume of the gas chamber in the pressure oil tank 1 gradually increases, and the liquid level in the tank gradually decreases while the total amount of turbine oil remains unchanged. When the pressure rises back to the preset second pressure threshold, the spiral Bourdon tube 22 expands and deforms, driving the first valve 3 to close completely, cutting off the gas source. The pressure at the front end of the inlet of the second valve 4 disappears, and the valve disc 47 and valve stem 45 return to their original position under their own weight and the action of the spring 48, closing the second valve 4. When the liquid level drops below the normal upper limit, the float 5 descends, the magnetic repulsion between the magnetic ring and the locking rod 43 disappears, and the locking rod 43 slides back to the lower left position along the first chamber 42 under the action of its own gravity component, locking the valve stem 45 again, and the device returns to standby state.

[0041] The third operating condition: normal pressure, liquid level above the normal upper limit. When the pressure is within the normal range, the spiral Bourdon tube 22 in the first-stage gas supply unit is in equilibrium, and the first valve 3 remains closed. The high liquid level causes the float 5 to approach the locking rod 43, releasing the magnetic lock. However, the closure of the first valve 3 results in no gas supply pressure at the inlet of the second valve 4, preventing the valve disc 47 from being pushed, and the second valve 4 remains closed. The device does not supply gas. This condition indicates that gas is not supplied only when the liquid level is high and the pressure is normal, avoiding unnecessary gas consumption.

[0042] The fourth operating condition: The pressure is below the first pressure threshold, the liquid level is above the normal upper limit, and the liquid level has not yet fallen back after the pressure recovers during the gas replenishment process. This is a continuation of the second operating condition. When the pressure recovers to the second pressure threshold and the first valve 3 closes, if the liquid level is still above the normal upper limit due to the float 5 being stuck or the oil level dropping slowly, the locking lever 43 remains unlocked. When subsequent system oil consumption causes the pressure to drop below the first pressure threshold again, the first valve 3 reopens. Since the locking lever 43 is still unlocked, the second valve 4 immediately opens to replenish gas. This state continues until the liquid level drops below the normal upper limit and the locking lever 43 returns to its locked state. This mechanism ensures that each pressure drop during the period of excessive liquid level triggers gas replenishment, accelerating the recovery of the liquid level to normal and forming a negative feedback regulation.

[0043] The fifth operating condition: The pressure is below the first pressure threshold, the liquid level is above the normal upper limit, but the air supply pressure is insufficient. If the air supply pressure is too low, it may not be able to push the valve disc 47 to overcome the spring force of the spring 48. In this case, even if the first valve 3 is open and the locking rod 43 is unlocked, the valve disc 47 cannot move upward, the second valve 4 cannot open, and the air supply fails. To prevent this situation, the air supply pressure must always be higher than the maximum working pressure of the pressure tank 1 by a certain value. Power plant compressed air systems are usually equipped with pressure monitoring and alarms, and maintenance personnel should handle the situation promptly when the air supply pressure is lower than the set value.

[0044] This invention also provides a turbine speed control system incorporating the aforementioned air replenishment device. The system includes components such as a pressure oil tank 1, an air replenishment device, a pressure oil pump, a return oil tank, and a relay. The pressure oil tank 1 is pre-filled with turbine oil and compressed air in an appropriate volume ratio (e.g., 1:2). This ratio has been determined through long-term practice, ensuring both sufficient pressure energy reserve and a reasonable oil pump replenishment cycle. The air inlet of the air replenishment device is connected to the power station's compressed air main pipe, which is equipped with a filter and a pressure reducing valve to ensure clean air and stable pressure. The exhaust port of the air replenishment device is connected to the air chamber of the pressure oil tank 1 via a check valve to prevent backflow of oil or air. During unit operation, the air replenishment device automatically replenishes air according to changes in pressure and level in the pressure oil tank 1, maintaining a stable oil-air ratio and pressure without manual intervention, thus avoiding the safety risks associated with high-pressure oil discharge operations. The air replenishment device employs a purely mechanical structure, does not rely on electrical components, and is unaffected by electromagnetic interference or power outages, exhibiting high reliability.

[0045] To verify the technical effects of the technical solutions described in the embodiments of the present invention, the inventors conducted a simulation experiment. The experiment used a pressure oil tank 1 of appropriate volume, initially filled with oil to the normal oil level, and then filled with gas to the normal working pressure. By simulating internal leakage, the pressure was slowly reduced to below the first pressure threshold, while simultaneously, external oil injection was used to raise the liquid level above the normal upper limit. The operation of the gas replenishment device was observed: the first valve 3 automatically opened, with the opening degree increasing linearly as the pressure decreased. When the pressure rose back to the normal working pressure, the ball valve automatically closed, and the liquid level dropped to the normal range. No pressure overshoot or liquid level fluctuation occurred throughout the entire process. After multiple continuous runs, the device operated reliably without jamming or leakage. Experimental data shows that the gas replenishment device provided in the embodiments of the present invention can operate stably for a long period.

[0046] This invention also provides a method for replenishing air to a giant turbine governor. This method is based on a turbine governor air replenishment device and includes the following steps: Step 1. Obtain the current pressure inside the pressure tank.

[0047] Step 2. When the current pressure is lower than the preset first pressure threshold, the pressure sensing actuator drives the first valve to open to replenish gas into the pressure tank, and the opening degree of the first valve is negatively correlated with the current pressure. Step 3. Obtain the current liquid level in the pressure tank.

[0048] Step 4. When the current liquid level exceeds the preset first liquid level threshold, the liquid level sensor drives the locking rod to release the lock on the second valve.

[0049] Step 5. With the first valve open and the second valve unlocked, the gas passes through the first valve and the second valve in sequence into the pressure oil tank.

[0050] Step 6. When the current pressure rises to the preset second pressure threshold, the pressure sensing actuator drives the first valve to close.

[0051] Step 7. When the current pressure is lower than the first pressure threshold and the current liquid level is lower than the first liquid level threshold, the locking lever remains locked to the second valve, and the second valve remains closed.

[0052] Step 8. After the first valve is closed, the air supply pressure at the front end of the second valve disappears, and the second valve automatically closes under its own weight of its stem and disc.

[0053] Step 9. When the current liquid level drops from above the first liquid level threshold to below the first liquid level threshold, the liquid level sensor releases the driving force on the locking rod, and the locking rod automatically resumes locking the second valve by its own weight.

[0054] The turbine governor air supply device and air supply method provided in this embodiment of the invention have the following beneficial effects: The turbine governor air replenishment device and method provided in this invention connects a first-stage air replenishment unit and a second-stage air replenishment unit in series between the air source and the pressure oil tank. A pressure-sensing actuator automatically controls the opening and closing of the first valve based on the pressure in the pressure oil tank, achieving linear regulation of the air replenishment flow. Simultaneously, a level sensor controls the locking or unlocking of the second valve based on the liquid level in the pressure oil tank, allowing gas to enter the pressure oil tank only when the liquid level exceeds a preset threshold. This turbine governor air replenishment device and method employs a purely mechanical structure, requiring no external power supply or control program. It can automatically complete the air replenishment operation based on two parameters: pressure and liquid level, maintaining the pressure and oil level in the pressure oil tank within the normal range, thus avoiding the safety risks associated with manual operation.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A gas supply device for a turbine governor, characterized in that, It includes a first-stage air supply unit and a second-stage air supply unit; the first-stage air supply unit and the second-stage air supply unit are connected in series between the air source and the pressure oil tank of the giant water turbine governor. The first-stage air replenishment unit includes a first valve and a pressure sensing actuator. The pressure sensing actuator is connected to the inside of the pressure tank and drives the first valve to open and close according to the pressure inside the pressure tank. The second-stage air replenishment unit includes a second valve and a liquid level sensor. The air inlet of the second valve is connected to the air outlet of the first valve, and the air outlet of the second valve is connected to the inside of the pressure oil tank. The liquid level sensor is used to sense the liquid level in the pressure oil tank and releases the lock on the second valve when the liquid level exceeds a preset threshold.

2. The air supply device for the turbine governor according to claim 1, characterized in that, Pressure-sensing actuators include: spiral Bourdon tubes; The pressure acquisition end of the outer ring of the spiral Bourdon tube is connected to the inner cavity of the pressure tank, and the free end of the inner ring of the spiral Bourdon tube is connected to the operating rod of the first valve. When the pressure in the pressure tank changes, the Bourdon tube deforms and drives the operating rod of the first valve to rotate through the transmission mechanism to open and close it.

3. The air supply device for the turbine governor according to claim 2, characterized in that, The pressure-sensing actuator also includes: a central gear and a sector gear; The first valve is configured as a ball valve; The central gear is rotatably mounted on the inner wall of the Bourdon tube housing, and the rotation direction of the central gear is consistent with the adjustment direction of the operating rod of the first valve; The sector gear is rotatably mounted on the inner wall of the Bourdon tube housing. The free end of the inner ring of the Bourdon tube is connected to the sector gear, and the sector gear meshes with the central gear. The end face of the central gear is perpendicular to the operating rod of the first valve, and the center of the central gear is fixedly connected to the operating rod of the first valve.

4. The air supply device for the turbine governor according to claim 3, characterized in that, The second valve includes: valve body, locking rod, valve stem, valve disc, sealing ring, and float in the flapper level gauge; The valve body is provided with a first chamber for installing the locking rod, a second chamber for installing the valve stem, and a third chamber for installing on the valve disc; The first chamber is configured as an inclined structure with different heights at both ends; the locking rod is configured as a magnetic gravity rod, which is installed in the first chamber and slides between the two ends of the first chamber; The second chamber is configured as an inclined structure with different heights at both ends, and the upper end of the second chamber is connected to the lower end of the first chamber; the valve stem is located in the second chamber, with the upper end of the valve stem perpendicular to the locking rod, and the valve stem slides between the two ends of the second chamber; The third chamber is horizontally positioned, and the valve disc is inclinedly positioned within the third chamber. A sealing ring is inclinedly positioned within the third chamber and connected to the inner wall of the third chamber. The valve disc moves within the third chamber, engaging with the sealing ring to connect or block the two ends of the third chamber. The upper end of the valve disc is fixedly connected to the lower end of the valve stem. The end of the third chamber corresponding to the lower end of the valve disc is configured as an air inlet for connecting to the air outlet of the first valve. The end of the third chamber corresponding to the upper end of the valve disc is configured as an exhaust outlet for connecting to the upper end of the inner cavity of the pressure tank. The level sensing element is set as the float in the flap level gauge. The float has a built-in magnetic ring, and the magnetic poles of the locking rod and the magnetic ring are the same at the opposite end. The second valve is installed at the flap level gauge of the pressure oil tank, and its installation height is the upper limit of the normal oil level of the pressure oil tank. When the float moves away from the locking rod, the locking rod slides down to the lower end of the first chamber under its own weight and locks the valve stem. When the float moves closer to the locking rod, the locking rod slides to the upper end of the first chamber under the action of repulsive magnetic force to release the lock on the valve stem.

5. The air supply device for the turbine governor according to claim 4, characterized in that, Also includes: spring; The middle position of the second chamber is set as an enlarged cylindrical chamber; A circular baffle is fixed on the valve stem, and the valve stem passes through the center of the circular baffle and is fixedly connected to it; A circular baffle is installed inside a cylindrical cavity; a spring is sleeved on the valve stem and is also installed inside the cylindrical cavity; the upper end of the cylindrical cavity limits the upper end of the spring, and the upper end of the circular baffle limits the lower end of the spring.

6. The turbine governor air supply device according to claim 2, characterized in that, The first-stage air replenishment unit also includes: a fixing component; The pressure-sensing actuator is fixed to the upper end of the pressure tank by a fixing assembly.

7. The turbine governor air supply device according to any one of claims 4-6, characterized in that, The sealing ring is a rubber sealing ring.

8. A method for replenishing air in a giant water turbine governor, characterized in that, This method is implemented based on the turbine governor air supply device according to any one of claims 1-7, and the method includes the following steps: Step 1. Obtain the current pressure inside the pressure tank; Step 2. When the current pressure is lower than the preset first pressure threshold, the pressure sensing actuator drives the first valve to open to replenish gas into the pressure tank, and the opening degree of the first valve is negatively correlated with the current pressure. Step 3. Obtain the current liquid level in the pressure tank; Step 4. When the current liquid level exceeds the preset first liquid level threshold, the liquid level sensor drives the locking rod to release the lock on the second valve; Step 5. With the first valve open and the second valve unlocked, the gas passes through the first valve and the second valve in sequence and enters the pressure oil tank. Step 6. When the current pressure rises to the preset second pressure threshold, the pressure sensing actuator drives the first valve to close; Step 7. When the current pressure is lower than the first pressure threshold and the current liquid level is lower than the first liquid level threshold, the locking lever remains locked to the second valve, and the second valve remains closed. Step 8. After the first valve is closed, the air supply pressure at the front end of the second valve disappears, and the second valve automatically closes under its own weight of its stem and disc. Step 9. When the current liquid level drops from above the first liquid level threshold to below the first liquid level threshold, the liquid level sensor releases the driving force on the locking rod, and the locking rod automatically resumes locking the second valve by its own weight.

9. A turbine speed control system, characterized in that, It includes a pressure oil tank and a turbine governor air supply device as described in any one of claims 1-7; the air supply device is connected to the pressure oil tank and is used to automatically maintain the pressure and liquid level in the pressure oil tank.

10. The turbine speed regulation system according to claim 9, characterized in that, The volume ratio of turbine oil to compressed air in the pressure tank is 1:2.

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