Hydraulic

Sander Marine hydraulic actuators are designed for the local or remote operation of valves in ballast, bilge, fuel, seawater and other auxiliary shipboard systems. The range includes both linear and hydraulic part-turn actuators, covering different valve types, operating requirements and fail-safe functions.

Hydraulic part-turn actuators are primarily used for 90° quarter-turn valves, including butterfly valves and ball valves, where controlled rotary movement and defined operating torque are required. Depending on the application, they are available in double-acting and spring-return configurations, with spring-to-close or spring-to-open operation according to the required fail-safe position.

Linear hydraulic actuators are mainly used for globe-type shut-off valves and SDNR (Screw Down Non-Return) valves, where linear stem movement and controlled actuator thrust are required. Depending on the version, they can be supplied with fail-safe spring-return operation and provisions for manual emergency operation.

The actuator system can be combined with central or local hydraulic power units, hand pumps, hydraulic control blocks, limit switches, position sensors or indicators, and suitable control systems. This allows remote valve operation together with open/closed position feedback and integration with the vessel’s automation or monitoring system.

Special configurations are also available for installation in demanding marine environments and, depending on the actuator type, for temporarily submerged or submerged operating conditions.

Hydraulic Actuator Selection

Correct actuator selection should take into account:

• Valve type and construction

• Required torque for rotary valves or thrust for linear valves

• Valve operating differential pressure

• Available hydraulic system pressure

• Required stroke or angle of rotation

• Double-acting or single-acting operation

• Required fail-safe position, fail-open or fail-close

• Requirement for manual emergency operation

• Position indication or feedback requirements

• Environmental and installation conditions onboard the vessel

Actuator sizing should always be based on the actual torque or thrust requirements of the valve and the operating conditions of the specific shipboard system.