Subsea Valve Actuator Increases Energy Efficiency

Bosch Rexroth’s subsea valve actuator (SVA), a new concept for underwater actuators which offers SIL3 safety levels and up to 75% lower energy consumption, has been granted a Mechanical Engineering Design Award. In May 2019, the SVA received the Award of Merit as one of five finalists in the 2019 Woelfel Best Mechanical Engineering Achievement Award. The award was presented at the Offshore Technology Conference in May 2019 by the American Society of Mechanical Engineers (ASME).

The SVA was developed to help address some of the challenges and shortcomings associated with either purely electromechanical or electrohydraulic actuator technology used on the sea floor for oil and gas exploration and production systems.

The SVA provides an energy-efficient, safe alternative to the actuators previously used in offshore oil and gas production. SVAs are autonomous assemblies with their own fluid circuit and a variable-speed pump drive. As a result, there is no need for a central power unit and fluid lines many kilometers long. The SVAs require a power supply and data line. A displacement control system adjusts the flow virtually loss-free based on the speed. This simplifies the design and significantly increases energy efficiency: compared to purely electro-mechanical actuators, SVAs require up to 75% less electricity at peak loads.

The integrated cylinder opens and closes drilling valves on the seabed. A safety valve with a mechanical spring ensures that the cylinder can close the drilling valve reliably without an external energy supply even if the power supply fails. The cylinder can be operated from outside by an underwater robot via a spindle. All components in the drivetrain have a doubly redundant design. As a result, the solution offers several levels of safety. Compatible with Industry 4.0 technology, the built-in sensor system continually records operating states within the actuator – including position, temperature and pressure – and forwards the data to the higher-level control system. This control system can evaluate trends and can detect and rectify deviations from the normal operating state early on – reducing the likelihood of downtime and enabling predictive maintenance to be scheduled where necessary.

Image credit: Bosch Rexroth
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