Yielding higher quality results from improved recovery and reduced sediment disturbance, the Feritech piston corer is an option alongside the standard gravity corer.
The FT520 piston corer combines operational safety with survey efficiency and reliability it is a standard and very popular tool within marine survey. The improved recovery and less disturbed sediment sample yields a higher quality result compared to that of a standard gravity corer.
The piston reduces internal friction between the sediment and the liner, this helps to prevent samples plugging the liner and reducing the sample return.
– Full ocean depth rating
– 1-12m barrels in 1m increments
– Configurable weights from 200-1000kg
– Manual or automatic releasing trigger
– Type A barrel – OD 101.6mm, sample – 84mm
– Type B barrel – OD 127mm, sample – 106mm
– Hydrostatic safety release
– Integration with Feritech HUB software
– Consumables in stock
– Various LARS options available
The automatic drop trigger system has been developed to aid recovery. Once the trigger weight or small gravity corer on the messenger wire touches the seabed and releases the piston corer from the trigger mechanism, it slackens its grip and drops down to the end of lift wire. This simplifies recovery as there is no gap between the trigger and the corer.
Hydrostatic Safety Release
The piston corer is fitted with our hydrostatic safety release system, which is designed to prevent false triggering, which dramatically improves operational safety. This means that the corer only triggers when it reaches a predetermined water depth.
Launch and recovery system
The piston corer has an optional, over-the-side, launch and recovery system (LARS). This greatly improves deployment and recovery efficiency, it also makes the changing of barrels much simpler and safer.
The LARS improves safety for the engineers working with the equipment ensuring the corer is securely held on deck and can be handled securely.
Pictured right – Feritech FT516 power track LARS
How does a piston corer work?
Both piston coring and jumbo piston coring work in much the same way. A jumbo piston corer has a wider diameter barrel and can be as much as 30m long where as a standard piston corer is typically up to 9m long. The trigger mechanism is based around the Kullenberg design.
On the way down through the water column the Feritech hydrostatic safety release arms at the set depth, this allows the piston corer to release when it reaches the sea floor.
The piston corer is released when a weight (or small gravity corer) on the end of a messenger wire touches the seabed and allows the tripping arm to open.
Once released the main piston corer free falls into the sea floor under its own mass (anywhere between 200kg to 1000kg for our standard piston corer and 500kg to 4000kg for the jumbo piston corer)
As the piston corer penetrate the seafloor, the piston inside stops at the sea floor. As the corer penetrates the action of the piston creates a pressure differential at the top of the sediment column that encourages marine soil to enter the core liner in an undisturbed state.
At the same time the Feritech trigger arm and mechanism slackens its hold on the lifting wire and drops down to be on top of the corer once again ready for simple recovery.
After a few seconds the coring process is complete and the system is recovered back on to the vessel so that the core can be processed.