According to the needs of hydropower station operation and maintenance, in the water diversion system of the turbine, a corresponding gate or valve is usually installed on the water diversion pipe of the turbine or in front of the volute, and the valve installed in front of the volute of the turbine is called the water inlet valve, and the butterfly valve is a commonly used water inlet valve.
Compared with other types of water inlet valves, the butterfly valve has the advantages of simple structure, small size, light weight, low cost, and easy operation. Its disadvantage is that the valve affects the flow of water and causes large hydraulic losses.
The butterfly valve is mainly composed of a hydraulic annular servomotor, a bypass valve, a cylindrical valve body, a valve rotating around the axis in the middle, and other components.
Under the action of the hydraulic annular servomotor, when the butterfly valve is closed, the circumference of the valve contacts the valve body, closing the water flow path; when it is opened, the valve is parallel to the water flow direction, and the water flows around both sides of the valve.
Among the components of the butterfly valve, the hydraulic annular servomotor is the main component for operating the valve. The quality of its working performance will directly affect the safe and stable operation of the turbine generator set.
The opening and closing of the butterfly valve is completely completed by the rotation of the hydraulic annular servomotor.
The power of the butterfly valve hydraulic annular servomotor mainly comes from the oil pressure system. The oil pressure operating system consists of two oil pumps, oil valves, hydraulic valves, four-way slide valves, and oil pipelines.
The hydraulic annular servomotor is composed of a butterfly valve main shaft, annular cylinder, piston, action arm, half-key, chamber partition and oil inlet and outlet holes. The butterfly valve and the main shaft are an integral whole, and the main shaft is connected to the action arm through the half-key.
Under the action of the pressure oil, the piston of the hydraulic annular servomotor takes the butterfly valve main shaft as the rotation center and moves along the annular cylinder, and then pushes the butterfly valve main shaft to rotate through the action arm connected to the piston, and the main shaft drives the valve to rotate, thereby achieving the purpose of opening and closing the butterfly valve.
