Introduction The DBS Pier-Mounted dual concentric drum output drive unit represents state of the art in reliability and performance. Two independent drive units are stacked concentrically together to drive a rake mechanism and a turbine. The rake drive is a low-speed, high-torque, totally enclosed gear drive with positive output torque overload protection. The turbine drive is a heavy-duty, higher speed, totally enclosed gear drive. The specially designed final output precision bearings provide superior life and reliability in excess of 100 years. The forged alloy steel gears and pinions are designed for a minimum life of 20 years. DBS Pier-Mounted dual concentric drum output drive units are typically used on solids contact and flocculating clarifiers or softeners. The drive unit is supported by a column in the center of the tank. DBS drive units are mounted on tanks that range from 40 to 300 feet (12 to 100 m) in diameter.

DD-Series Capacities

10-year warranty on main gear-bearing Rake drive has accurate torque gauge calibrated in ft-lbf, N-m or any units required Forged alloy steel main gear-bearing designed for over 20 years of life as calculated per AGMA 2001-C95 Variable speed turbine drive is standard Alarm and cutoff switches and maximum torque-limiting via shear pin or pressure relief valve Permanently lubricated rake intermediate gear box, oil bath lubricated main gear housings

Rake Torque Capacity - Pier-Mounted Dual Drives TURBINE DRIVE POWER1     Model Continuous Maximum Overload Yield Allowable Max. Speed ft-lbf N-m ft-lbf N-m ft-lbf N-m Horsepower rpm D30-A*-D30 16,000 22,000 32,000 44,000 94,000 127,000 25 32 D30-B*-D30 27,000 36,500 54,000 73,000 94,000 127,000 25 32 D42-B*-D42 35,000 47,500 70,000 95,000 195,000 264,000 50 24 D42-C*-D42 51,000 69,000 102,000 138,000 195,000 264,000 50 24 D60-C*-D60 65,000 88,000 130,000 176,000 440,000 597,000 75 17 D60-D*-D60 110,000 149,000 220,000 298,000 440,000 597,000 75 17 D80-D*-D80 145,000 196,500 290,000 393,000 750,000 1,017,000 100 13 D80-E*-D80 250,000 339,000 500,000 678,000 750,000 1,017,000 100 13 D42-B*2-D42 70,000 95,000 140,000 190,000 390,000 528,000 50 24 D42-C*2-D42 102,000 138,000 204,000 276,000 390,000 528,000 50 24 D60-C*2-D60 130,000 176,000 260,000 352,000 880,000 1,194,000 75 17 D60-D*2-D60 220,000 298,000 440,000 596,000 880,000 1,194,000 75 17 D80-D*2-D80 290,000 393,000 580,000 786,000 1,500,000 2,034,000 100 13 D80-E*2-D80 500,000 678,000 1,000,000 1,356,000 1,500,000 2,034,000 100 13 1 For higher horsepower requirements or higher speed, consult factory. Replace the * with the primary reducer option selected. Continuous: Torque at which main gear will have a life in excess of 20 years at normal operating speeds. Maximum Overload: The maximum safe, short term operating torque. Yield: The structural maximum torque based on the minimum yield strength of the main gear.

DD-Series Dimensions

	Item Description 1 Machine frame 2 Drive drum, rake 3 Main gear-bearing, rake 4 Drive drum, turbine 5 Main gear-bearing, turbine 6 Pinion support bearing, turbine 7 Pinion, turbine 8 Primary speed reducer, turbine 9 Primary drive, turbine 10 Oil drain, turbine 11 Oil drain, rake 12 Primary speed reducer, rake 13 Planetary gearbox, rake 14 Pinion, rake 15 Pinion support bearing, rake

Model A B C D Std. Mounting Flange1 Weight      in     mm     in     mm     in     mm     in     mm     in mm     lb     kg     D30-A*-D 48     1,219     47     1,194     5     127     14.25     362     32 813     5,200     2,359     D30-B*-D 48     1,219     47     1,194     5     127     14.25     362     32 813     6,400     2,903     D42-B*-D 60     1,524     60     1,524     5     127     14.5     368     44 1,118     8,000     3,629     D42-C*-D 60     1,524     60     1,524     5     127     14.5     368     44 1,118     8,600     3,901     D60-C*-D 84     2,134     80     2,032     6     152     17.75     451     62 1,575     12,800     5,806     D60-D*-D 84     2,134     80     2,032     6     152     17.75     451     62 1,575     14,800     6,713         1 Maximum standard outside diameter of mounting flange. For larger flange sizes, consult factory.     Replace the * with the primary reducer option selected.

Rake Primary Speed Reducer Options

Turbine Variable Speed Primary Reducer Options

Mechanical type variable speed reducer

The mechanical variable speed reducer is a ring-cone or a disc design. The output speed varies as the pitch-line distance between two rotating components decreases or increases. The speed variation is adjusted by turning a hand-wheel on the reducer. These reducers include a standard NEMA C-frame on both the input and output connections for easy installation and removal. The reducers provide a 5:1 variable speed range.

Electrical type variable speed reducer

The electrical type variable speed reducer is a variable frequency drive (VFD) that controls the output speed of the electric motor. The VFD can be mounted near the drive unit or at a remote location. VFDs provide a clean, maintenance- free, and economical way of attaining variable speed. Standard features include forward and reverse, speed indication, motor overload protection, soft-start, 4-20 mA signal, and monitoring of operating conditions. These reducers provide a 5:1 variable speed range or 10:1 when used with an inverter duty motor.

Hydraulic type variable speed reducer

The hydraulic type variable speed reducer is a stand-alone industrial hydraulic power unit with a variable volume piston pump and hydraulic motor combination for speed reduction. This design is used when the rake primary speed reducer is an H-type design. A screw located on the pump is turned to change the stroke of the pump pistons and vary the amount of oil delivered to the hydraulic motor, thus varying the final output speed of the drive unit. These speed reducers provide a 3:1 variable speed range.

Ordering Information

Pier-Mounted Dual Concentric Drum Output Drive Unit Model Number Turbine Specification Extension Series   Rake Gear   Pitch Dia.   (Inches)  -    Secondary   Speed   Reducer   Primary   Speed   Reducer   Number   of Pinions  -    Turbine   Turbine Gear   Pitch Diameter   (Inches)   Maximum   Turbine HP D 30 A E F H 1 (omit) D 30 42 25 50 B 42 B 1 (omit) 2 42 60 50 75 C 34 C 1 (omit) 2 3 4 60 80 75 100 D 44 D 80 100 E

Example: Model D30-AF-D3015

D is for a pier-mounted drive unit; 30 is the size of the final rake gear pitch diameter in inches; A is the size of the secondary speed reducer; F is the type of the primary reducer; D is for turbine drive; 30 is the size of the turbine gear pitch diameter in inches; 15 is the turbine horsepower.

Standard Features
	Alarm and cutoff switches
	3 sets of O&M manuals
	6" torque gauge indicating real torque (not available on H-type primary reducer)

Optional Features
	4-20 mA torque transducer
	Bi-directional operation (available for F and H-type primary reducers)
	Loss motion switch
	4-20 mA lift position transducer
	Variable speed, turbine
	Variable speed, rake
	Special coating
	Special electric motor
	Oil heater (available for F and H-type primary reducers and main gear housing)
	Oil temperature switch
	Oil level switch
	Explosion proof switches