Two-Ram Steering Gear with Redundancy:
This system utilizes two separate hydraulic circuits, each powering one of the two rams (cylinders) that control the rudder. Key features of this design for redundancy include:
- Dual Pumps and Reservoirs: The system incorporates two separate hydraulic pumps and reservoirs. Each pump and reservoir supplies fluid to its respective steering ram, creating independent circuits.
- Directional Control Valves: Two directional control valves, one for each circuit, control the flow of hydraulic fluid to each ram. These valves are typically solenoid-operated, receiving electrical signals to direct fluid flow.
- Isolation Valves: Isolation valves are strategically placed in each circuit, typically located near the reservoirs or pumps. These valves can be manually closed to isolate a specific circuit in case of a failure.
- Priority Valve (Optional): An optional priority valve can be incorporated to prioritize one circuit over the other in case of a pressure drop in one system. This ensures that at least one steering ram remains operational.
Operation:
During normal operation, both hydraulic circuits function simultaneously. When the directional control valves are actuated, they direct hydraulic fluid flow to either side of their respective rams, causing the rams to extend or retract, turning the rudder accordingly.
Maintaining Steerage During Hydraulic Pipe Failure:
If a hydraulic pipe failure occurs in one circuit, the isolation valve in that circuit can be manually closed to isolate the leak. The remaining operational circuit can then continue to provide hydraulic power to its corresponding ram, allowing the rudder to be controlled with reduced steering capability.
Benefits of Redundant System:
- Improved Reliability: The dual-circuit design offers a higher level of reliability compared to a single-circuit system. Even with a pipe failure, steerage can potentially be maintained.
- Enhanced Safety: Redundancy helps ensure better maneuverability and control of the vessel in case of a hydraulic system malfunction, reducing the risk of accidents.
Limitations:
- Increased Complexity: Redundant systems involve more components, leading to increased complexity and potentially higher maintenance costs.
- Weight and Space: The additional pumps, reservoirs, and valves add weight and require more space for installation.
In conclusion, a two-ram steering gear with a redundant hydraulic system provides a reliable solution for steering control while offering a safety measure in case of hydraulic pipe failure.