Synchronous turbine stator blade adjusting system and adjusting method

Abstract

The invention provides a turbine stationary blade synchronous adjusting system which is used for solving the technical problems that a left oil cylinder and a right oil cylinder of existing turbine equipment stationary blade adjustment are not synchronous, an oil cylinder piston rod is corroded by a corrosive and toxic medium, and leakage is caused through sealing of an adjusting cylinder. The double-servo oil cylinder unit is connected with the hydraulic control unit, and the synchronism of the stroke of the left servo oil cylinder and the stroke of the right servo oil cylinder is achieved through fine adjustment of the four throttling adjusting valves. The invention further provides a turbine stationary blade synchronous adjusting method which comprises the steps that the two position transmitters are adopted for detecting the stroke positions of the double servo oil cylinders correspondingly, and position information is transmitted to the PLC control unit; when the PLC control unit detects that the positions of the left servo oil cylinder and the right servo oil cylinder are not synchronous, the PLC control unit controls the four throttling adjusting valves to adjust the oil inlet amount or the oil outlet amount of the double servo oil cylinders respectively, and the phenomenon that the double oil cylinders are not synchronous due to the cavity effect is avoided.

Description

Technical Field

[0001] The present invention relates to a control system and method for stator blades of a turbine, and particularly to a synchronous control system and method for stator blades of a turbine. Background Art

[0002] Most axial-flow turbine devices adopt the stator blade control method to achieve variable operating condition control, so as to improve the unit efficiency. The stator blade control system adopts a dual-cylinder drive mode, and the dual cylinders are driven and adjusted through servo valve control. The dual cylinders include a left cylinder and a right cylinder. The servo valve is integrated on the right cylinder, and the displacement sensor is installed on the left cylinder. The PLC control system collects the displacement output parameters output by the displacement sensor, compares the data with the given signal, and sends the difference signal after comparison to the servo valve on the right cylinder, so as to control the left and right cylinders to form a closed-loop control circuit. Therefore, the stator blade control requires that the dual cylinders have the same speed, high synchronous accuracy, small self-friction coefficient, low starting pressure, no low-speed crawling and stalling phenomena, and good response characteristics during operation to meet the synchronization requirements.

[0003] However, due to the self-sealing structure and machining errors of the servo cylinders, the resistances, frictions, and internal leakage amounts of the dual cylinders during operation are different, resulting in inconsistent thrusts and deteriorated control accuracy of the left and right servo cylinders, thus causing an out-of-synchronization problem; the connection pipeline errors of the left and right servo cylinders lead to inconsistent cavity effects, which will also cause an out-of-synchronization problem; in addition, if the medium in the cylinder is a corrosive and toxic medium, it will corrode the cylinder piston rod, and long-term operation will cause operation jamming and out-of-synchronization of the left and right cylinders, and the out-of-synchronization of the left and right cylinders will further cause problems such as operation jamming, deteriorated control accuracy, and even breakage of the connecting rod, affecting the normal operation of the turbine device. Summary of the Invention

[0004] The purpose of the present invention is to solve the technical problems of out-of-synchronization of the left and right cylinders in the stator blade control of the existing turbine device, corrosion of the cylinder piston rod by the corrosive and toxic medium, and leakage through the regulating cylinder seal, and to propose a synchronous control system and method for stator blades of a turbine.

[0005] To solve the above technical problems, the technical solution provided by the present invention is as follows:

[0006] A synchronous control system for stator blades of a turbine, characterized in that it includes a hydraulic control unit, a dual servo cylinder unit connected to the hydraulic control unit, a regulating unit connected to the dual servo cylinder unit, and an airtight sealing unit and a PLC control unit connected to the regulating unit;

[0007] The double servo cylinder unit includes a left servo cylinder and a right servo cylinder. The rodless cavity of the left servo cylinder is connected to a first throttle regulating valve, and the rod cavity is connected to a second throttle regulating valve; the rodless cavity of the right servo cylinder is connected to a third throttle regulating valve, and the rod cavity is connected to a fourth throttle regulating valve; the first throttle regulating valve, the second throttle regulating valve, the third throttle regulating valve, and the fourth throttle regulating valve are all connected to the hydraulic control unit;

[0008] The regulating unit includes a turbine equipment regulating mechanism, a left regulating cylinder, and a right regulating cylinder. The left regulating cylinder and the right regulating cylinder are respectively connected to the turbine equipment regulating mechanism and are used to drive the turbine equipment regulating mechanism to move axially; the left servo cylinder is connected to the left regulating cylinder, the right servo cylinder is connected to the right regulating cylinder, and the left regulating cylinder and the right regulating cylinder are also respectively connected to a left position transmitter and a right position transmitter, which are used to collect stroke position information and transmit the stroke position information to the PLC control unit. The PLC control unit outputs a feedback signal and controls the oil flow direction in the hydraulic control unit.

[0009] Further, the inflatable sealing unit includes an air inlet and an air outlet, as well as a first ball valve, a regulating valve, a second ball valve, a stop valve, and a check valve connected in series in sequence; the air inlet is connected to the first ball valve, and the air outlet is connected to the check valve; a differential pressure transmitter is connected to the regulating valve.

[0010] Further, the hydraulic control unit includes an electro-hydraulic servo valve and a hydraulic station connected to the electro-hydraulic servo valve; the electro-hydraulic servo valve includes a first oil port and a second oil port. The first throttle regulating valve and the third throttle regulating valve are connected to the first oil port, and the second throttle regulating valve and the fourth throttle regulating valve are connected to the second oil port.

[0011] Further, inflation ports are arranged on both the left regulating cylinder and the right regulating cylinder, and the inflation ports are connected to the air outlet of the inflatable sealing unit.

[0012] Further, the gas filled into the inflatable sealing unit through the air inlet is nitrogen.

[0013] Further, a third ball valve is also connected in parallel between the input end of the first ball valve and the output end of the second ball valve and is used as a bypass branch.

[0014] A method for synchronously regulating the stationary blades of a turbine, based on the above-mentioned turbine stationary blade synchronous regulating system, is characterized in that it includes the following steps:

[0015] 1) Detect the stroke position information of the left servo cylinder through the left position transmitter, and detect the stroke position information of the right servo cylinder through the right position transmitter, and transmit the stroke position information to the PLC control unit;

[0016] 2) The PLC control unit compares the stroke position information of the left and right servo cylinders and outputs a feedback signal. If the feedback signal indicates that the two stroke positions are synchronized, the synchronization requirement is met; if the feedback signal indicates that the two stroke positions are not synchronized, the flow direction of the oil in the electro-hydraulic servo valve is controlled according to the feedback signal, and the first throttle regulating valve, the second throttle regulating valve, the third throttle regulating valve, and the fourth throttle regulating valve are adjusted accordingly.

[0017] 3) When the feedback signal indicates non-synchronization in the closing direction, the first oil port of the electro-hydraulic servo valve is controlled to admit oil, and the second oil port is controlled to discharge oil; the first throttle regulating valve and the third throttle regulating valve are adjusted to respectively control the oil inflow into the rodless chambers of the left and right servo cylinders to achieve a synchronous state; or the second throttle regulating valve and the fourth throttle regulating valve are adjusted to respectively control the oil outflow from the rod chambers of the left and right servo cylinders to achieve a synchronous state.

[0018] When the feedback signal indicates non-synchronization in the opening direction, the first oil port of the electro-hydraulic servo valve is controlled to discharge oil, and the second oil port is controlled to admit oil; the second throttle regulating valve and the fourth throttle regulating valve are adjusted to respectively control the oil inflow into the rod chambers of the left and right servo cylinders to achieve a synchronous state; or the first throttle regulating valve and the third throttle regulating valve are adjusted to respectively control the oil outflow from the rodless chambers of the left and right servo cylinders to achieve a synchronous state.

[0019] Further, the non-synchronization in the opening direction means that when the pistons in the left and right servo cylinders move simultaneously from the rod chamber to the rodless chamber, during the movement process or when reaching a certain position, the positions of the two pistons are not synchronized.

[0020] Further, the non-synchronization in the closing direction means that when the pistons in the left and right servo cylinders move simultaneously from the rodless chamber to the rod chamber, during the movement process or when reaching a certain position, the positions of the two pistons are not synchronized.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] 1. For a turbine stator blade synchronous adjustment system of the present invention, the first throttle regulating valve and the third throttle regulating valve are connected to the first oil port of the hydraulic control unit to respectively adjust the oil inflow or outflow of the left and right servo cylinders; the second throttle regulating valve and the fourth throttle regulating valve are connected to the second oil port of the hydraulic control unit to respectively adjust the oil inflow or outflow of the left and right servo cylinders; through the cooperation of the four throttle regulating valves, the present invention can respectively adjust the oil inflow components and oil outflow components of the left and right servo cylinders, effectively solve the non-synchronization phenomenon of the left and right cylinders in the operation of a turbine device driven by double cylinders due to internal deviations and external influences in the cylinders, and achieve better synchronous control.

[0023] 2. A synchronous adjustment system for the stationary blades of a turbine in the present invention, wherein the inflation sealing unit is connected to the adjustment unit. Inflation ports are provided on both the left adjustment cylinder and the right adjustment cylinder. Nitrogen enters the inflation sealing unit and flows into the inflation port from the air outlet after passing through a series-connected first ball valve, regulating valve, second ball valve, stop valve, and check valve in sequence. Nitrogen with a pressure higher than the medium pressure is filled into the left adjustment cylinder and the right adjustment cylinder to prevent corrosive medium from entering the adjustment cylinder, effectively preventing the leakage of harmful media and keeping the piston rod in the nitrogen medium all the time, thereby achieving the purpose of anti-corrosion and anti-leakage.

[0024] 3. A synchronous adjustment method for the stationary blades of a turbine in the present invention uses two position transmitters to respectively detect the stroke positions of the double servo cylinders and transmit the position information to the PLC control unit; when the PLC control unit detects that the positions of the left servo cylinder and the right servo cylinder are not synchronous, the staff adjusts the oil inlet or oil outlet of the double servo cylinders respectively through four throttle regulating valves according to the feedback signal to make up for the phenomenon of non-synchronization of the two cylinders caused by the cavity effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic structural diagram of a synchronous adjustment system for the stationary blades of a turbine in the present invention;

[0026] Figure 2 is a flow chart of a synchronous adjustment method for the stationary blades of a turbine in the present invention.

[0027] DESCRIPTION OF THE REFERENCE NUMERALS:

[0028] 10. Hydraulic control unit, 11. Electro-hydraulic servo valve, 12. Hydraulic station; 21. Left servo cylinder, 22. Right servo cylinder, 23. First throttle regulating valve, 24. Second throttle regulating valve, 25. Third throttle regulating valve, 26. Fourth throttle regulating valve; 30. Turbine equipment adjustment mechanism, 31. Left adjustment cylinder, 32. Right adjustment cylinder, 33. Left position transmitter, 34. Right position transmitter; 40. Inflation sealing unit, 41. First ball valve, 42. Regulating valve, 43. Differential pressure transmitter, 44. Second ball valve, 45. Stop valve, 46. Check valve, 47. Third ball valve. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The present invention will be further described below with reference to the drawings and embodiments.

[0030] The present invention provides a synchronous adjustment system for the stationary blades of a turbine, as Figure 1 shown. The adjustment system includes a hydraulic control unit 10 and a double servo cylinder unit connected to the hydraulic control unit 10. The double servo cylinder unit is connected to the adjustment unit, and the adjustment unit is connected to an inflation sealing unit 40 and a PLC control unit.

[0031] The double servo cylinder unit includes a left servo cylinder 21 and a right servo cylinder 22. Both the inside of the left servo cylinder 21 and the right servo cylinder 22 contain a rodless chamber and a rod chamber. The rodless chamber of the left servo cylinder 21 is connected to the first throttle regulating valve 23, and the rod chamber is connected to the second throttle regulating valve 24; the rodless chamber of the right servo cylinder 22 is connected to the third throttle regulating valve 25, and the rod chamber is connected to the fourth throttle regulating valve 26. The hydraulic control unit 10 includes an electro-hydraulic servo valve 11 and a hydraulic station 12, and the electro-hydraulic servo valve 11 is connected to the hydraulic station 12. The electro-hydraulic servo valve 11 includes a first oil port and a second oil port, and the PLC control unit controls the flow direction of the fluid flowing inside the electro-hydraulic servo valve 11, thereby controlling the first oil port and the second oil port to be used for oil inlet or oil outlet respectively. The first throttle regulating valve 23 and the third throttle regulating valve 25 are connected to the first oil port of the electro-hydraulic servo valve 11, and correspondingly responsible for regulating the oil inlet volume or oil outlet volume of the rodless chambers of the left servo cylinder 21 and the right servo cylinder 22; the second throttle regulating valve 24 and the fourth throttle regulating valve 26 are connected to the second oil port of the electro-hydraulic servo valve 11, and correspondingly responsible for regulating the oil inlet volume or oil outlet volume of the rod chambers of the left servo cylinder 21 and the right servo cylinder 22.

[0032] The regulating unit includes a left regulating cylinder 31, a right regulating cylinder 32 and a turbine equipment regulating mechanism 30. The left regulating cylinder 31 and the right regulating cylinder 32 are respectively connected to the turbine equipment regulating mechanism 30 through connecting components, and synchronously drive the turbine equipment regulating mechanism 30 to move axially to realize the static blade regulation of the turbine equipment. The left servo cylinder 21 is connected to and drives the left regulating cylinder 31, and the right servo cylinder 22 is connected to and drives the right regulating cylinder 32. The left regulating cylinder 31 is connected to a left position transmitter 33, and the right regulating cylinder 32 is connected to a right position transmitter 34. The left position transmitter 33 and the right position transmitter 34 are respectively used to collect the stroke position information of the left servo cylinder 21 and the right servo cylinder 22, and transmit the stroke position information to the PLC control unit. The PLC control unit compares the stroke positions of the left servo cylinder 21 and the right servo cylinder 22, and outputs a feedback signal. The staff makes corresponding adjustments to the first throttle regulating valve, the second throttle regulating valve, the third throttle regulating valve and the fourth throttle regulating valve according to the feedback signal. Inflation ports are provided on both the left regulating cylinder 31 and the right regulating cylinder 32 of the regulating unit.

[0033] The inflatable sealing unit 40 includes an air inlet and an air outlet, and nitrogen is filled through the air inlet. After the gas enters through the air inlet, it sequentially passes through a first ball valve 41 serving as a cut-off valve, a regulating valve 42 with an automatic adjustment function, a second ball valve 44 serving as a cut-off valve, a globe valve 45 for manual adjustment, and a check valve 46. The gas finally flows out through the check valve 46, and the check valve 46 has the function of preventing the medium from flowing back. The regulating valve 42 is connected with a differential pressure transmitter 43. A third ball valve 47 is also connected in parallel between the input end of the first ball valve 41 and the output end of the second ball valve 44, and the third ball valve 47 serves as a bypass branch. The air outlet of the inflatable sealing unit 40 is respectively connected to the air filling ports on the left adjusting cylinder 31 and the right adjusting cylinder 32. Through the differential pressure transmitter 43 of the regulating valve 42, nitrogen higher than the medium pressure is filled into the left adjusting cylinder 31 and the right adjusting cylinder 32, avoiding the corrosion medium from entering the adjusting cylinder, effectively preventing the leakage of harmful media, and keeping the piston rod in the nitrogen medium all the time, so as to achieve the purpose of anti-corrosion and anti-leakage.

[0034] A method for synchronously adjusting the stationary blades of a turbine includes the following steps:

[0035] 1) Detect the stroke positions of the left servo cylinder 21 through the left position transmitter 33 and the stroke positions of the right servo cylinder 22 through the right position transmitter 34, and transmit the stroke position information to the PLC control unit;

[0036] 2) The PLC control unit compares the stroke positions of the left servo cylinder 21 and the right servo cylinder 22 and outputs a feedback signal. If the feedback signal indicates that the two stroke positions are synchronous, the synchronism requirement is met; if the feedback signal indicates that the two stroke positions are not synchronous, according to the feedback signal, the PLC control unit controls the oil flow direction in the electro-hydraulic servo valve 11, and at the same time, the staff makes corresponding adjustments to the first throttle regulating valve 23, the second throttle regulating valve 24, the third throttle regulating valve 25, and the fourth throttle regulating valve 26;

[0037] 3) The bidirectional movement conversion of the servo cylinder is achieved through the conversion of the oil flow direction. The movement of the piston in the servo cylinder is driven by the oil pressure. The movement of the piston from the rod chamber to the rodless chamber means that the rod chamber is filled with oil and the rodless chamber discharges oil; the movement from the rodless chamber to the rod chamber means that the rodless chamber is filled with oil and the rod chamber discharges oil. The simultaneous movement of the pistons in the left servo cylinder 21 and the right servo cylinder 22 from the rod chamber to the rodless chamber means that the rod chamber is filled with oil and the rodless chamber discharges oil. When the positions of the pistons are not synchronous during the movement process or when they reach a certain position, this is defined as out-of-synchronism in the opening direction;

[0038] When the feedback signal is open and out of sync, the PLC control unit controls the first oil port of the electro-hydraulic servo valve (11) to discharge oil and the second oil port to intake oil; adjust the second throttle regulating valve (24) and the fourth throttle regulating valve (26) to respectively control the oil intake volume into the rod chambers of the left servo cylinder (21) and the right servo cylinder (22) to make them reach the synchronous state; or adjust the first throttle regulating valve (23) and the third throttle regulating valve (25) to respectively control the oil discharge volume from the rodless chambers of the left servo cylinder (21) and the right servo cylinder (22) to make them reach the synchronous state.

[0039] The pistons in the left servo cylinder 21 and the right servo cylinder 22 move simultaneously from the rodless chamber to the rod chamber, which means the rod chamber discharges oil and the rodless chamber intakes oil. When the pistons are out of sync during the movement or at a certain position, it is the closing out of sync at this time.

[0040] When the feedback signal is closing and out of sync, the PLC control unit controls the first oil port of the electro-hydraulic servo valve (11) to intake oil and the second oil port to discharge oil; adjust the second throttle regulating valve 24 and the fourth throttle regulating valve 26 to respectively control the oil discharge volume from the rod chambers of the left servo cylinder 21 and the right servo cylinder 22 to make them reach the synchronous state. Or adjust the first throttle regulating valve (23) and the third throttle regulating valve (25) to respectively control the oil intake volume into the rodless chambers of the left servo cylinder (21) and the right servo cylinder (22) to make them reach the synchronous state.

[0041] The turbine equipment is tested when it leaves the factory, and the synchronism of the double cylinders is detected through the test device at the test bench position. The out-of-sync problem of the double cylinders can be finely adjusted by adjusting the opening degrees of the four throttle speed control valves; after the turbine equipment is installed on site, the out-of-sync problem caused by the pipeline and the installation process can also be solved by fine-tuning and correcting again through the four different throttle speed control valves.

Claims

1. A synchronous adjustment system for a stationary vane, characterized in that: It includes a hydraulic control unit (10), a double servo cylinder unit connected to the hydraulic control unit (10), an adjustment unit connected to the double servo cylinder unit, and an inflation sealing unit (40) and a PLC control unit connected to the adjustment unit; The double servo cylinder unit includes a left servo cylinder (21) and a right servo cylinder (22). The rodless chamber of the left servo cylinder (21) is connected to a first throttle valve (23), and the rod chamber is connected to a second throttle valve (24); the rodless chamber of the right servo cylinder (22) is connected to a third throttle valve (25), and the rod chamber is connected to a fourth throttle valve (26); the first throttle valve (23), the second throttle valve (24), the third throttle valve (25), and the fourth throttle valve (26) are all connected to the hydraulic control unit (10); The adjustment unit includes a turbine equipment adjustment mechanism (30), a left adjustment cylinder (31), and a right adjustment cylinder (32). The left adjustment cylinder (31) and the right adjustment cylinder (32) are respectively connected to the turbine equipment adjustment mechanism (30) and are used to drive the turbine equipment adjustment mechanism (30) to move axially; the left servo cylinder (21) is connected to the left adjustment cylinder (31), the right servo cylinder (22) is connected to the right adjustment cylinder (32), and the left adjustment cylinder (31) and the right adjustment cylinder (32) are also respectively connected to a left position transmitter (33) and a right position transmitter (34) to collect stroke position information and transmit the stroke position information to the PLC control unit, and the PLC control unit outputs a feedback signal and controls the oil flow direction in the hydraulic control unit (10).

2. A turbine stator blade synchronous adjustment system according to claim 1, characterized in that: The inflation sealing unit (40) includes an air inlet and an air outlet, and a first ball valve (41), a regulating valve (42), a second ball valve (44), a stop valve (45), and a check valve (46) connected in series in sequence; the air inlet is connected to the first ball valve (41), the air outlet is connected to the check valve (46); a differential pressure transmitter (43) is connected to the regulating valve (42).

3. A turbine stator blade synchronous adjustment system according to claim 1, characterized in that: The hydraulic control unit (10) includes an electro-hydraulic servo valve (11) and a hydraulic station (12) connected to the electro-hydraulic servo valve (11); the electro-hydraulic servo valve (11) includes a first oil port and a second oil port, the first throttle valve (23) and the third throttle valve (25) are connected to the first oil port, and the second throttle valve (24) and the fourth throttle valve (26) are connected to the second oil port.

4. A turbine stator blade synchronous adjustment system according to claim 2, characterized in that: Inflation ports are provided on both the left adjustment cylinder (31) and the right adjustment cylinder (32), and the inflation ports are connected to the air outlet of the inflation sealing unit (40).

5. A turbine stator blade synchronous adjustment system according to claim 4, characterized in that: The gas filled into the inflation sealing unit (40) through the air inlet is nitrogen.

6. A stator vane synchronous adjustment system according to claim 5, characterized in that: A third ball valve (47) is also connected in parallel between the input end of the first ball valve (41) and the output end of the second ball valve (44) and is used as a bypass branch.

7. A method for synchronous adjustment of stator vanes, based on the synchronous adjustment system of stator vanes according to any one of claims 1-6, characterized in that: It includes the following steps: 1) Detect the stroke position information of the left servo cylinder (21) through the left position transmitter (33), detect the stroke position information of the right servo cylinder (22) through the right position transmitter (34), and transmit the stroke position information to the PLC control unit; 2) The PLC control unit compares the stroke position information of the left servo cylinder (21) and the right servo cylinder (22), and outputs a feedback signal. If the feedback signal is that the two stroke positions are synchronous, the synchronization requirement is met; if the feedback signal is that the two stroke positions are not synchronous, the flow direction of the oil in the electro-hydraulic servo valve (11) is controlled according to the feedback signal, and the first throttle regulating valve (23), the second throttle regulating valve (24), the third throttle regulating valve (25), and the fourth throttle regulating valve (26) are adjusted accordingly; 3) When the feedback signal is that the closing directions are not synchronous, control the first oil port of the electro-hydraulic servo valve (11) to intake oil and the second oil port to discharge oil; adjust the first throttle regulating valve (23) and the third throttle regulating valve (25) to respectively control the oil intake volume entering the rodless chambers of the left servo cylinder (21) and the right servo cylinder (22) to make them reach a synchronous state; or adjust the second throttle regulating valve (24) and the fourth throttle regulating valve (26) to respectively control the oil discharge volume flowing out of the rod chambers of the left servo cylinder (21) and the right servo cylinder (22) to make them reach a synchronous state; When the feedback signal is that the opening directions are not synchronous, control the first oil port of the electro-hydraulic servo valve (11) to discharge oil and the second oil port to intake oil; adjust the second throttle regulating valve (24) and the fourth throttle regulating valve (26) to respectively control the oil intake volume entering the rod chambers of the left servo cylinder (21) and the right servo cylinder (22) to make them reach a synchronous state; or adjust the first throttle regulating valve (23) and the third throttle regulating valve (25) to respectively control the oil discharge volume flowing out of the rodless chambers of the left servo cylinder (21) and the right servo cylinder (22) to make them reach a synchronous state.

8. A stator vane synchronous adjustment method according to claim 7, characterized in that: The opening direction not being synchronous means that when the pistons in the left servo cylinder (21) and the right servo cylinder (22) move simultaneously from the rod chamber to the rodless chamber, during the movement process or when moving to a certain position, the positions of the two pistons are not synchronous.

9. A stator vane synchronous adjustment method according to claim 7, characterized in that: The closing direction not being synchronous means that when the pistons in the left servo cylinder (21) and the right servo cylinder (22) move simultaneously from the rodless chamber to the rod chamber, during the movement process or when moving to a certain position, the positions of the two pistons are not synchronous.

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