Operation method
In medium and small hydropower stations, the inlet valve operates in three modes: manual operation, electric operation and hydraulic operation.
The general micro unit inlet valve is manually operated. The inlet valve of the small unit is generally operated by electric operation. On the electric operating mechanism, there is also a manual operation mechanism to ensure the reliable operation of the inlet valve. The water inlet valve is opened and closed by a motor or a manually operated handle through a shifting mechanism (ie, a reduction gearbox) and a screw, a nut, and a boom.
For large diameter inlet valves that require large operating torques, hydraulic operation is used to ensure the closing speed of the inlet valve.
Regardless of the type and operation mode of the main valve, the valve should be opened when the water pressure on the upper and lower sides of the inlet valve is basically equal, the sealing device is removed from the working position, and the lock ingot is removed. Static water is turned on). The inlet valve is not allowed to open in the case of moving water, as this increases the operating torque and does not require operation. When the normal operation is closed, it should be satisfied that the inlet valve can be closed (hydrostatic shutdown) after the turbine guide vane is completely closed and the lock is released. In the event of an accident, after the inlet valve receives the accident shutdown signal, the lock can only be withdrawn, and the turbine vane can be closed without shutting down (water shut). When the inlet valve is operated to the fully open or fully closed position, the lock bar must be re-introduced.
The working state of the inlet valve is only in the two positions of full opening and full closing, and the inlet valve cannot be operated at a certain position in the middle, that is, it cannot be used instead of the water guiding blade to regulate the flow.
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