LAWSON ENGINEERS LTD Ref : PJ1682
Issue Date : 06.06.2006
Coiler DCV Stack Item 91,92 and 93.
The sensors on the coiler
control this valve electrically; it moves the coiler in either direction. A pressure reducer
controls the pressure to the coiler motor.
Winch Stack Items 84,85
.
This valve controls the flow to the winch motors. The
joystick on the desk proportionally controls them.
A-Frame Stack Items 87,88 and 97.
This valve controls the flow to the Luff,
Leg Extend/Retract and Skid Extend/Retract. The joystick on the desk proportionally
controls them. A relief valve is fitted to prevent excessive pressure to the A-Frame
circuit.
Overload Isolation Valve Items 113 and 114 An overload protection valve is fitted
which is connected to the load cell output, it will only allow oil through this valve when
the load cell is working within the system parameters. If overload occurs the valve closes
stopping flow to the full bore area of the cylinder but allowing flow to the annulus area of
the cylinder allowing the rod to be retracted.
Latch Drain Check Valve Item 15. Fitted in the drain line from the latch sequence valve
this valve prevents any backpressure in the drain line from opening the latches.
Latch Sequence Valve Item 31.
This valve will only allow the latches to open when
sufficient pressure has built up in the latch open line. When the pressure decays the valve
returns the oil in the latch cylinders to drain giving a fast response.
Snubber Raise/Lower Pressure Reducing Valves Item 80. These valves are set at a very
low pressure to prevent the Snubber Raise/Lower Cylinders from exerting excessive
force, causing damage to the flotation on the ROV or TMS.
Snubber Raise/Lower Counter Balance valve Item 81.
These valves are fitted to
control the flow in and out of the Snubber Raise/Lower Cylinders and prevent the
cylinders from extending if there is a burst hose.
Snubber In/Out Stack Items 103,104 and 106. This is part of the 5-stack manifold on the
Snubber. Push buttons on the control desk control it. Dual Relief Valves are fitted which
allows the snubber to swing if the load induces a pressure exceeding the counterbalance
valve setting.
Snubber Lock/Damping Stack Items 94,95 and 96.
This valve is located close to
the 5-stack manifold on the Snubber and is Teed into the A and B lines of the Snubber
In/Out Stack. In the energised condition the spool is all ports blocked allowing the
Snubber In/Out Stack to operate normally. In the de-energised condition it allows oil
from the Snubber Damping Cylinders to flow through the flow control slices giving
control of the speed of swing of the snubber.
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