Hydraulic circuit for ram cylinder

A hydraulic circuit for a ram cylinder, the hydraulic circuit comprising:

• the ram cylinder which drives a driven device such as a flap gate and a spillway gate;
• a hydraulic unit including (i) a supply circuit including a supply control valve which is connected to a discharging side of a hydraulic power supplier and controls supply of hydraulic oil discharged from the hydraulic power supplier, and a supply throttle valve which controls an amount of hydraulic oil supplied to the ram cylinder, and (ii) a discharge circuit including a discharge control valve which is connected to an oil tank and controls discharge of hydraulic oil returned from the ram cylinder, and a discharge throttle valve which controls an amount of hydraulic oil returned from the ram cylinder;
• a first supply/discharge circuit which connects the ram cylinder with the supply circuit of the hydraulic unit and a second supply/discharge circuit which connects the ram cylinder with the discharge circuit of the hydraulic unit;
• and
• a bypass circuit which connects (i) a portion of the supply circuit of the hydraulic unit that portion is downstream from the supply control valve and the supply throttle valve and (ii) a portion of the discharge circuit that portion is downstream from the discharge control valve and the discharge throttle valve, the bypass circuit including a stop valve having an opening/closing function,
• wherein the hydraulic circuit further comprises:
• a flushing circuit for flushing the ram cylinder, the flushing circuit established when the bypass circuit closes communication between the supply circuit of the hydraulic unit and the discharge circuit of the hydraulic unit;
• and
• a driving circuit for driving the ram cylinder, the driving circuit established when the bypass circuit establishes communication between the supply circuit of the hydraulic unit and the discharge circuit of the hydraulic unit.