Product Model: HD7X41X

Nominal Diameter: DN150~4000mm

Nominal Pressure: PN0.25~4.0MPa

Applicable Temperature: ≤80°C

Applicable Media: Clean water, seawater, muddy water, oil products, etc.

Product Overview 
The hydraulic slow-closing check butterfly valve is a relatively advanced pipeline control device both domestically and internationally. It is mainly installed at the inlet of hydraulic turbines in hydropower stations, serving as the turbine inlet valve; or installed at the outlet of water pumps in various pumping stations for water conservancy, power, and water supply/drainage, replacing the functions of check valves and gate valves. During operation, it cooperates with the main pipeline unit. According to the principle of hydraulic transients (water hammer theory), it achieves reliable shut-off of the pipeline through preset opening/closing procedures, effectively eliminating pipeline water hammer and protecting the safety of the pipeline system.

Working Principle 
The stored closing energy of the counterweight type hydraulic slow-closing check butterfly valve is the potential energy of the counterweight. It is further divided into the counterweight type automatic pressure-holding hydraulic slow-closing check butterfly valve (referred to as counterweight pressure-holding type) and the locking counterweight type automatic pressure-holding hydraulic slow-closing check butterfly valve (referred to as counterweight locking type). The main working conditions include centrifugal pump conditions, axial-flow pump conditions, and hydraulic turbine conditions, etc.

• Valve opening under centrifugal pump condition (including centrifugal mixed-flow pumps): Start the pump first, and open the valve after a preset delay.
• Valve opening under axial-flow pump condition (including axial-flow mixed-flow pumps): Open the pump and valve simultaneously, or open the valve to a certain angle first, and then start the pump.
• Valve opening under hydraulic turbine condition: Open the bypass valve to balance the pressure first, then open the valve, and finally start the hydraulic turbine.
• Various working conditions generally require the valve to be closed simultaneously with shutdown or power failure.

Basic Electro-hydraulic Working Principle:

• When opening the valve: The solenoid valve reverses, the oil pump starts, and hydraulic oil enters the hydraulic cylinder through the flow control valve and high-pressure hose, pushing the piston to drive the connected lever to lift the counterweight and open the valve. After the valve is fully open, the automatic pressure-holding system starts; the motor continues to charge the pressure-holding accumulator. When the pressure reaches the high-pressure set point, the oil pump stops. Rotating the handwheel of the flow control valve can adjust the opening time, with an adjustment range of 10 to 90 seconds.
• System leakage: If the pressure drops to the low-pressure set point, the oil pump motor automatically starts and stops after reaching the high-pressure set point.
• When closing the valve: The solenoid valve reverses, and the pressure oil in the cylinder returns to the oil tank through the quick and slow closing throttle valves, high-pressure hose, and solenoid valve. The counterweight falls, and the connecting rod drives the disc to rotate and close the valve, rapidly cutting off most of the water flow during the first 70% of the stroke; the last 30% of the stroke closes slowly. The quick and slow closing angles and the buffering time of each stage can be adjusted according to the actual pipeline conditions to effectively eliminate pipeline water hammer; the adjustment time is 2 to 25 seconds for quick closing and 6 to 90 seconds for slow closing.
• During the opening and closing process, the valve can be stopped at any intermediate position via the stop button. The stop action is mainly used for system debugging.
• The manual pump is mainly used for system debugging. In the absence of electricity or when the oil pump cannot work normally, cranking the manual pump can also complete the valve opening and system pressure holding. Open the normally closed stop valve, and under the action of the counterweight potential energy and hydrodynamic torque, the connecting rod drives the disc to rotate and close the valve.