Oil & Gas Engineering - Actuator Closure Time Analysis


During field tests at a terminal, a valve failed to meet the standard closure time of 60 seconds. The actuator control system required modification to comply with the standard. 

The actuator control system consisted of a hydraulic power unit, accumulator racks and a separate valve control panel. The HPU, accumulation and control panel were all located remotely from the valve and actuator. The control panel was connected to the actuator via 3/4" supply and return tubing. 


A site survey was conducted to confirm; 

  • The hydraulic fluid type and the available volume 
  • The number, size and type of accumulators 
  • The diameter, length and elevation of tubing runs 

CVs were calculated for key components where no published data was available. The existing system was modelled in hydraulic simulation software and validated against site test results. 


Use of lower viscosity fluid and increased diameter tubing was shown to reduce closure time to below 60 seconds over a temperature range of -10°C to +25°C. The results of the report gave the client confidence in the proposed solution. After changes were made, the field trial results were in line with the simulation. 

Maximising our value 

The client was able make an informed decision preventing costly and disruptive trial and error.