~1). Hydraulic control valves opened by hydraulic-driven and closed by counter-weight’s potential energy provides excellent and reliable operation.
 2). The valve is installed behind the pumps and served as both gate valve/butterfly valve and check valve with only 30% flow resistance coefficient of above two kinds of valves. It provides significant energy saving.
 3). The operation of hydraulic actuator is divided into two steps of quick closing from 90° to 30° and slow closing from 30° to 0°. The closing speed and angle can be adjusted according to working condition to prevent excessive water hammer.
 4). The above three models of valves can be operated manually when power failure.
 5). HD743X valve features in auto-resetting. When the valve opening reduces by 15°, the oil pump starts and make the counter weight return to original position.
 6). HD7BT43X Features in:
 A. The valve closing is divided into two steps of quick closing from 60°～80° in 5～20 seconds
 and slow closing from 30°～10° in 10～50 seconds.
 B. Pressure Retaining
 The hydraulic actuator is equipped with an energy accumulator storing with pressure oil to
 compensate pressure when leak occurs.
 C. Standby Resetting Device