15 August 2002
Collector Channel. The collector channel, a wide, deep, grating covered
open culvert leading to the pump suction chamber, handles the greater portion of water
pumped out of the flooded graving dock.
Sand Sumps. Abrasive materials harmful to pumps and pump fittings are
continuously washed off a graving dock floor in sufficient quantities to justify the
installation of a settling basin. Provide settling basins to retain most of these harmful
suspended particles. Locate these basins in an accessible part of the collector channel
to permit easy removal of collected sediment and sand. Other methods of containing
this material may be used as an alternate, such as floor barriers around the ship.
Dewatering Pump Suction Chamber. Provide a suction chamber (large
enclosed space) for the dewatering pumps next to or in dock sidewalls, preferably near
the dock entrance. Specific design requirements are:
Locate the chamber floor below the graving dock floor; shape it to conform
to flow lines of water entering pump suction bells, if necessary.
Provide depressions in chamber floor to serve as sumps for low capacity
Provide access to the main suction chamber through manholes or through
the collector channel itself.
Pumping Plant. Provide a pumpwell of reinforced concrete for housing
the pumps, motors, valves, gates, controls, and other equipment. Pump suction
chambers constitute the lower part of a pumpwell.
Pumps and Motors. Several functional types of pumps with motors may
be housed in a pumpwell; main dewatering units predominate. Other pump and motor
Salt water pumps (fire protection and flushing).
Vacuum pumps (if required for priming).
Valves and Gates. Include the following valves and sluice gates in a
Sluice gates between collector channel and main pump intakes.
Gate valves in discharge line from each main pump.