Subsea Valve Actuators

A valve actuator converts electrical energy into mechanical motion to open, close, or modulate a valve without manual intervention. In subsea applications, this enables remote control of pipeline flow, isolation valves, and process equipment from the surface or via an ROV, improving safety, response time, and operational precision at depth.

The three main types are linear actuators, which produce straight-line push or pull force; rotary actuators, which produce angular or continuous rotational motion; and hydraulic actuators, which use fluid pressure for high-force applications. NV Mechanics Design Ltd. offers both electric linear and rotary subsea actuators with integrated brushless motors and absolute encoders.

NV Mechanics Design Ltd. offers two depth rating tiers. The self-compensated linear and rotary actuators are rated to 3,000 msw (meters of seawater). The high-force linear actuators — including the Trunion 1000N and the 60,000 N Force model — are rated to 6,000 meters, covering the majority of commercially relevant subsea installations.

All actuators are available in Stainless Steel 316 (SST 316) or Titanium housings, both of which provide excellent resistance to seawater corrosion. Titanium is preferred for the most demanding deep-sea or high-salinity environments where weight reduction is also a priority. Seacon or Subcon-series underwater-rated connectors are used throughout.

Linear and rotary self-compensated actuators use a 30-bit absolute multi-turn encoder mounted directly on the output shaft, providing 14-bit single-turn resolution (16,383 counts/turn) plus a 16-bit turns counter. Critically, position data is retained between power cycles, eliminating the need for rehoming routines after shutdown or power loss at depth.

Self-compensated actuators communicate via RS422 (RS485 full-duplex on 4 wires) or RS232 at 19,200 baud. All control parameters, limit switches, and broadcast frequency settings are stored in internal EEPROM. High-force linear actuators use external resolver feedback. A Windows software utility and integration guides are also provided for commissioning support.