A standard IP65 linear actuator fulfils marine environment specification for valve positioning.
The Special Products Division of E.P Barrus Ltd, design and build customised marine engines for the RNLI, UK MoD and many global search and rescue organisations. Since the 1970s, Barrus has led the field in Post Immersion Restart System (PIRS) 2-stroke engines which have the ability to restart after complete submersion by rapidly evacuating water from the cylinder head, transfer ports and the fuel system. Following continuous product development in this demanding application area the Bicester-based manufacturer has now introduced a new generation of environmentally friendly 4-stroke engines which actually prevent water entering through the inlet, vents and exhaust system using a patented valve arrangement which is actuated immediately a sensor network detects that immersion has taken place. This new "˜Inversion Protected' technology not only cuts down restart time from typically 40 seconds to just 10 seconds - a major factor in a search and rescue situation - but also reduces internal engine damage or deterioration due to water ingress for much improved reliability and extended engine life.
As part of the specialised engine design, Barrus have selected Thomson Electrak 1 series linear actuators to drive the inversion protection valve following application support from motion control specialist Heason Technology. These IP65-rated linear actuators are mounted on the exposed engine, completely fulfilling the Barrus specification, but nonetheless are supplied as a low-cost off-the-shelf standard product. The Electrak1 features a simple 2-wire DC motor which is switched to actuate the valve following boat roll-over whilst a manual input is used to reset the system. The robust and durable sealed design includes an aluminium/zinc corrosion-resistant housing and stainless steel actuating rod.
Electrak 1 actuators are widely used and well proven across demanding applications in rigorous operating conditions and provide consistent, repeatable performance in extreme temperature and humidity conditions. The Electrak actuator was also chosen for its self-locking acme screw drive that will not allow the valve to back drive, and with the added benefit of a small and compact dimensions for convenient mounting within the space restricted marine engine. The clevis mount design makes installation and removal straightforward whilst the auto reset thermal switch motor protection and integral end-of-stroke limit switches ensure safe operation.
To learn more about Thomson Electrak 1 series linear actuators and other products, please visit www.heason.com.