Swell solution
March 1st 2008 Drilling in choppy seas is fraught
with hazards. As the sea swells
relative to the drilling platform, the
stresses and strains induced on a
drill pipe will alternately take the
weight of the ship or try to pull
itself out of the seabed.
A new servo hydraulic protection
system from Moog provides an
intelligent 'flow fuse' that not only
automatically resets, but regulates
the platform speed in the event of
an exceptional wave and
brings the platform to a
controlled stop in the event
of a drill break.
The system works by
pre-charging an
accumulator to a pressure
sufficient to hold the drill
weight. As the platform
moves up and down with
the heave of the sea
surface, hydraulic oil passes
backwards and forwards from
actuator to accumulator, keeping
the platform stationary relative to
the seabed. Each actuator has a
position sensor which enables the
Moog MSC Controller (M3000) to
monitor the position and velocity of
the platform. Two Moog DSHRE 80
servo cartridge valves regulate the
flow of the hydraulic oil with
capability to flow 6100L/min and to
open or close in 18 milliseconds. More articles from Moog Controls: | 
