1 Overview The Hongli Hydropower Plant is located in Xing'an League, Inner Mongolia. It is a power plant with seasonal irrigation mainly with irrigation, with a total installed capacity of 12,800kW. The power station is located on the Wanhe River which is 32km northwest of Wulanhaote. The power plant has less load and is scattered near the power plant. Therefore, most of the power needs to be fed into the system during the power generation season, and system reverse power is needed when the power is off. According to the basic parameters of the power station and the situation of domestic stereotypes, two types of hydro-generating units are selected. 1) 1,2 units. The hydraulic turbine is HLA501-LJ-140 type, rated output 3380kW, rated speed 300r / min, design head 27m, maximum head 32m, minimum head 14m, design flow 14.5m3 / s. Generator TS325 / 36-20, rated output 3200kW. Fei speed 670r / min. 2) Unit 3 and 4. Turbine HL240-LJ-I80, rated output 3470kW, rated speed 187.5r / min, design head 22m, the maximum head 28m, minimum head 14m, design flow 18.8m3 / s. Generator TSL330 / 60-32, rated output 3200kW, runaway speed 465r / min. On the 1st and 2nd machine, the pressure hole length is 37.83m and the hole diameter is 3.1m. Reinforced concrete lining. Bifurcation 0 10 105.5 bifurcation, after bifurcation hole diameter of 2.00m, to the factory before the gradient into a 1.75m into the plant, after the bifurcation are reinforced concrete Ming pipe, to withstand the pressure of filling, l2mm thickness lined steel plate to withstand Internal water pressure. 3,4 pressure machine diameter 3.1m, for the reinforced concrete pipe, after the hole diameter becomes 2.5m, using reinforced concrete Ming pipe, lined steel. Taking into account the overhaul and safe operation of the unit, Unit 1 and 2 are pre-installed with a φ1.75m butterfly valve. 3,4 before the machine in the surge tank installed an accident slab gate. 2 The role and structure of butterfly valve According to the needs of hydropower station operation and maintenance, the water diversion system of the turbine is usually equipped with a corresponding gate or valve on the water diversion pipeline of the turbine or in front of the volute, and the device is installed in front of the turbine volute The valve is called the inlet valve, while the butterfly valve is the more common type of inlet valve. Butterfly valves are mainly composed of a hydraulic ring relay, a bypass valve, a cylindrical valve body, a shutter that pivots around the shaft and other components. Under the action of the hydraulic ring relay, when the butterfly valve is closed, the circumference of the valve contacts with the valve body to close the water flow passage; when it is opened, the valve is parallel to the water flow, and the water flows around the two sides of the valve. Compared with other types of inlet valves, butterfly valves have the advantages of simple structure, small size, light weight, low cost and convenient operation. The disadvantage of the valve is that the valve affects the flow pattern and the hydraulic loss is large. In butterfly valve components, hydraulic ring relay is the main part of the operating valve, the performance of its performance will have a direct impact on the safe and stable operation of the hydro-generator set. 3 switching principle Butterfly valve opening and closing valve completely rely on the rotation of the hydraulic ring to complete. Butterfly valve hydraulic torch relay work mainly from the hydraulic system, hydraulic operating system consists of two pressure pumps, oil valves, hydraulic valves and four-way valve and oil pipeline and other components. Hydraulic ring relay from the butterfly valve spindle, the annular cylinder, the piston, the role of arm, sub-half keys, sub-cavity partition and into the oil drain hole. Butterfly valve and the spindle as a whole, the main shaft through the half-key and the role of the arm connected. Hydraulic toroidal relay in the role of pressure oil, the piston butterfly valve spindle as the center of rotation, along the circular cylinder movement, and then through the role of the piston connected to the arm to promote butterfly valve spindle rotation, spindle driven valve rotation, so as to open, off Butterfly valve purpose. Butterfly valve opening and closing process The reason why the choice of hydraulic ring relay to operate because of the hydraulic ring relay has the outstanding advantages: do fixed-axis rotary drive, can overcome the straight cylinder-type relay drive starting zone and the limit zone Force arm shorter, leaving the shortcomings of force dispersion. However, the relative position between the annular relay cylinder and the butterfly valve main shaft, that is, the concentricity between the center of the annular cylinder and the main shaft of the butterfly valve, the perpendicularity between the annular center plane of the cylinder body and the axis of the main shaft of the butterfly valve are difficult to manufacture and install Guaranteed. 4 problems in the process of switching and handling measures Hongliu 1, 2, No. 1 butterfly valve valve diameter of 1.75m, relying on 2 sets of hydraulic ring relay operation. Because of the rigid connection between the piston and the action arm of the hydraulic ring relay, there is a seal between the piston and the cylinder. The main function of the seal is to prevent pressure oil leakage in the oil chamber. When operating, the hydraulic ring relay piston in the cylinder under the action of pressure oil to rotate, so as to drive the spindle to rotate the valve to open and close the purpose. Hongyi Power Plant 1, 2 butterfly valve was put into production in December 1989, during use, the hydraulic ring relay in the operation of butterfly valve often have some problems, so that the valve opening and closing has been unable to properly, open or Off a time, ranging from a few minutes, as many as ten minutes, and sometimes simply can not open or close, so a serious threat to the unit's safe and stable operation. The inspection found that the main reason is due to serious eccentric piston and annular cylinder wear, while partial wear diameter corresponding to the gap at the larger. This not only caused great resistance to the piston movement, while in the gap at the release of a large number of hydraulic pressure, the spindle and the valve insufficient force led to the butterfly valve open and closed blocked phenomenon. Analysis of the reasons, mainly because of the annular cylinder and the relative position of the butterfly valve spindle error caused by serious damage caused by the piston. In the butterfly valve hydraulic torque relay process, mainly the role of the arm and the piston connection form, from rigid connection to the elastic connection, so that the piston along the circular cylinder movement, can automatically generate radial displacement, The utility model can not only drive the action arm to be not restricted by the rigidity of the arm, but also can make the different super-deviation in manufacture and installation be automatically adjusted, and the working performance of the hydraulic torque relay is improved, and the satisfactory effect is achieved. Due to processing constraints, mainly on the piston thrust plate was processed. The thrust plate and the role of the arm shaft and hole with the transition from the original to match the dynamic fit to ensure the radial displacement of the thrust plate is greater than or equal to 2mm still use the role of the shaft end of the arm 6 M16 , Increase the thrust plate and the role of the arm connection; bolt 2 quasi 20 and hole Φ30 with the gap should be less than 2.5mm, axial clearance 0.05 ~ 0.1mm, to ensure that the radial piston movement is neither blocked, but also The axial displacement is controlled, the sealing cover 1 and the sealing gasket 3 are compacted by the screw and the thrust plate to form a sealing device. 5 Conclusion butterfly valve hydraulic toroidal piston after processing, the manual operation test, in the no-load state, the butterfly valve open, off once only 15s; in the static state, the butterfly valve on and off once need 18 ~ 25s , Greatly shortening the opening and closing time, but also the Butterfly valve open and close process smoothly, hydraulic ring connector also no oil spill phenomenon. After the automation system is formed, the butterfly valve can be shut down quickly and reliably under the condition that the water guide mechanism runs out of control, which creates good conditions for the safe and stable operation of the unit.