Kerr-McGee Dredging Case Study

Application: Clean and dredge paint pigment residuals

Dredge Used: LWT 7MAU Series Pit Hog™ Dredge

Project Summary: Electric manned automated dredge with 3 Krebs cyclones with a capacity of 2,100 gpm, magnetic flow meter to monitor pump performance, slurry density meter to maintain consistent percent solids by varying traverse speed, and Bottom Sense™ (automated system to detect and protect pond bottom) to follow the contour of the pond and protect the liner.

Machinery Specifications: PIT HOG™ DREDGE, 7MAU SERIES MODEL Manned Electric Dredge with On-Board Solids Separation

General:
Length 47′-l0″ (14.58 m)
Width 13′-6″ (4.11 m)
Height 17′-1″ (Top of Overflow) (5.18 m)
Weight 62,000 lbs. (operational) (18,123 Kilos)
Draft. 2′-11″ (.9 m)

Flotation:
Catamaran Type Hull–Two Pontoons-56″ x 48″ x 40′ -0″ made from 1/4″ thick steel plate with Internal Bulkheads and Stiffeners, Polyurethane foam filled.

Cutter:
Auger Type with Shroud

Assembly:
Diameter (HeIix) 18-3/4″
Diameter (Knife Profile) 24-1/4″
Pitch 11″
Flighting 3/8″
Speed Variable to 60 RPM
Cutter Knives Detachable heat-treated blades
Cutter Torque Variable to 17.200 in.-lb.

Working: Cut 13′-6″ wide x l8″ deep (4.11 m)

Capacity: Digging depth-26′ maximum (7.9 m)

Power: 200 HP TEFC Motor – Dredge Pump, Underflow Pump
Service Water Pump and Ancillary Hydraulic Circuits

Pumps:
End Suction Centrifugal with Semi-open Impeller
Dredge Pump ~10″ x 8″ rubber lined with 22″ diameter impeller
Variable speed – 0 to 600 RPM
Design Capacity-2,l00 GPM @. 17 PSIG at cyclone inlet
Underflow Pump 4″ x 3″ rubber lined with 14″ diameter impeller
Variable speed ~ to 1200 RPM
Design Capacity-250 GPM @ 120 ft. head
Service Water Pump 2′ x 2′ self priming
Variable speed-0 to 2700 RPM
Design Capacity-50 GPM @ 120 ft. head

Solids: Three Krebs Model Dl5LB-T123 Cyclones

Separation: Capacity-2,100 GPM (700 GPM per cyclone)

Hydraulic: Slurry pump – Heavy Duty Hydrostatic Drive
All Other Circuits – Pressure-Volume Gear Pump

Systems:
Fixed Displacement Hydraulic Motor(s)
Capacity-7O GPM @ 1750 RPM Motor Speed
Reservoir-75 Gallons
Circuit One-Auger Drive
Circuit Two-Boom Hoist
Circuit Three-Traverse Winch
Circuit Four-Slurry Pump Drive

Relief Pressure Settings:
Slurry Pump Circuit – 4,500 PSI
All other circuits – 2,700 PSI

Propulsion:
Treble Sheave Hydraulic Winch
Traverse Speed – 0 to 100 FPM
Cutting Speed, Nominal – 8 to 12 FPM

Electrical System: Voltage-480V, 3-phase
Two Control Voltage Transformer(s)
120V Power Supply
4V Power Supply

Automation:
Operation Fully Automated with Monitors feeding Program Logic Control
Dredge Pump – 8″ Slurry Flow Meter Monitors Output/Sets Speed
Traverse Winch-8″ Slurry Density Meter sets speed
Underfiow Pump -Level Control sets speed; Flow Meter Monitors Output
Service Water Pump – 4″ Density Meter starts and stops pump
Cyclone Sump–Level Control signals Underflow Pump
Auger Position–Bottom Sense follows bottom contour–Boom up or down

Coating:
Immersed Surfaces – epoxy coating, 15 mils min. thickness
All other surfaces – Polyurethane enamel on a corrosion inhibitive primer, 5 mils min thickness