The actuator is shown in the fully charged, in the ready-to-close position.
In the first sequence the actuator is in the open position awaiting a demand to close signal. The valve may be operated locally, remotely or automatically by a variety of sensory and control devices. Until a demand signal is received, the piston accumulator remains in the fully charged state at the same pressure as the pipeline.
The actuator is now midway through the closing stroke and then fully closed.
In the second sequence, the actuator has received a demand to close signal and the actuator control system opens the flow paths to the rotary vane. The pressurized gas in the accumulator forces hydraulic fluid into the actuators closing port and powers the actuator in the clockwise direction. At the same time, non-pressurized fluid from the actuator’s opening port returns to the reservoir. Finally, the actuator has reached the fully closed position.
With the closing stroke complete, the actuator begins gas re-injection process
The ECAT system utilizes a compact electro-hydraulic motor and pump as the energy source to re-inject power gas back into the pipeline. Following valve operation, the motor/pump will automatically start, forcing hydraulic fluid back into the accumulator. As the accumulator fills with fluid, the power gas is re-injected back into the pipeline. The motor only runs for a short time during the gas re-injection process. Once the gas re-injection process is complete, the motor automatically stops and the system remains in a fully charged “ready to stroke” state awaiting a command to open the valve. When an open command is received, the control directs the flow paths to rotate the actuator in the counter-clockwise direction and the gas re-injection process repeats.
