VHR actuator designed by SNRI
Until 2012 cryogenic valves were fitted with standard actuators.
It turned out that these actuators did not meet the marine environment operating conditions, resulting in degradation of components and some dysfunctions.
Throughout interventions on the vessels, our technicians have detected some oil leakages around the cover.
After study, it was identified that this oil leakage is mainly linked to a too high pressure generated by the ambient temperature (in case of bunkering period in hot place like in Qatar, Malaysia, … ), which exceeds the maximum temperature defined by the ship technical specifications or after too quick cooling downs of the piping (with valve closed) before the unloading phase.
In both cases, it generates a jump of the internal pressure of the upper chamber of the actuator (up to 200 bar if external temperature is near 55°C, refer top graph 2).
To avoid these phenomena (applicable for large size actuators), SNRI has decided to develop an integrated oil damper which allows to withstand these unforeseen oil pressure variations
The results are significant: no more oil leakage - the oil damper absorbs the excess volume of oil and restores it when the temperature drops. This equipment is easily retrofittable on existing actuators and modification can be done by the crew with no dismantling. Please contact SNRI or VVS to get advice and proposal on this option.
