The Challenge of Subsea Position Sensing

One of the more challenging Hydraulic applications in the world exists far below the ocean, on the sea bed to be exact. A place where mother nature and the laws of entropy conspire to make all man made contraptions suffer, and challenge the ingenuity of engineers and scientists on a daily basis.

One such contraption is the large piston based hydraulic accumulators used in undersea mining and drilling operations as part of critical blowout preventer systems. In principle the operation of these systems is rather simple: The large hydraulic accumulator stands by full charged, ready to deliver massive force to the blowout preventer when a failure in the integrity of the pipeline is detected. The proper operation of the preventer, will prevent millions of gallons of crude oil from spilling into otherwise pristine waters.  The failure of the blowout preventer on the other hand, can cause spectacular failures and environmental disaster as is all too well remembered from the Deepwater Horizon debacle that cost 11 lives and untold damage to wildlife and local ecology.

Deploying Hydraulic Accumulators in a Sub-Sea Application

Because all hydraulic Accumulators leak over time, they must be periodically replaced to insure that charge pressure has not dropped as to make the cylinder ineffective in an emergency.  Imagine the cost involved of going down to the sea bed every 6 months to pull up and replace these accumulators, “just to be sure” they are in working condition.

A better solution uses a CPI SL-1500 sensor on the sea bed to detect the position of the piston in the accumulator. As the pre-charge pressure of the accumulator leaks, the CPI sensor sends back extremely accurate position signals which tell technicians when they “really” have to replace an accumulator.  By having real data on accumulator pressure, CPI sensors can save drilling operators hundreds of thousands of dollars by allowing them to intelligently delay the replacement of these Hydraulic cylinders until it is really needed. Alternately they can prevent a safety disaster by allowing operators to detect early failures of these accumulators.

For more information on our Subsea sensors like the SL – 1500, visit our hydraulic accumulator page.