- A low-speed, high-torque, totally enclosed gear drive with positive output torque overload protection
- The drive unit is supported by a column in the center of the tank
- The drive unit has an external rotating drive drum with attachment points for the rake cage
- The drive access bridge typically spans one half of the tank
- Used in industrial, municipal and mining clarifiers and thickeners
- Typically used on tank sizes from 40 to 300 ft (12 to 100 m) in diameter
- Forged alloy steel main gear and pinion designed for 20 years of life calculated per AGMA 2001-C95
- Precision, four-point-contact main bearing, with a 10-year warranty
- Accurate torque gauge calibrated in ft-lbf, N-m or any units desired
- Alarm and cutoff switches and maximum torque limiting via shear pin or pressure relief valve
- No lower pinion bearing, eliminating a common source of drive failure
- Designed for minimum maintenance with permanently lubricated secondary reducer
E-type primary speed reducer
The E-type design uses helical gears for speed reduction. It has alarm and cutoff switches and a shear pin to provide triple protection of the drive unit. This design is used where the output speed is outside the limits of the F-type primary speed reducers or when an electro-mechanical type drive unit is desired.
F-type primary speed reducer
The F-type design uses a hydraulic pump-motor combination for speed reduction. It has alarm and cutoff switches and hydraulic relief (equivalent to a shear pin in the E-type primary speed reducer) to provide triple protection of the drive unit. This design is positive torque-limiting and will operate under stalled and semi-stalled conditions. Optional reversing rotation and variable speed are available. The torque indication and protection system is equally accurate for operation in either direction.
H-type primary speed reducer
The H-type design has all the features of the F-type primary speed reducer. It uses a stand-alone industrial hydraulic power unit. This design is used on higher horsepower and multiple pinion drive applications.
W-type primary speed reducer
The W-type design uses helical gears for speed reduction. It has shear pin and shear pin activated cutoff switch to protect the drive unit. This is simplified E-type design used where a torque gauge and adjustable alarm switch are not required.
The DBS lift mechanism provides the ability to raise and lower the rakes up to 24 inches (600 mm). The D-series lift operates by raising the entire drive unit. The lift mechanism is fully contained within the drive unit. In most cases, the installation of a DBS lift equipped drive unit is no more complicated than a normal non-lifting clarifier drive.
The lift option is offered with manual or powered operation. The powered lift mechanism provides positive lift force control to prevent damage to the rakes or the screw jack.
Example: Model D30-AF-L1512F
D is for a pier-mounted drive unit; 30 is the size of the final gear pitch diameter in inches; A is the size of the secondary speed reducer; F is the type of the primary reducer; L is for a lift mechanism; 15 is the lift capacity in tons; 12 is the lift travel in inches; F is the type of the lift actuator.
- Alarm and cutoff switches
- 3 sets of O&M manuals
- 6″ torque gauge indicating real torque (not available on H-type primary reducer)
- 4-20 mA torque transducer
- Bi-directional operation (available for F and H-type primary reducers)
- Condensate control unit
- 4-20 mA lift position transducer
- Variable speed
- Loss motion switch
- Special electric motor
- Oil heater (available for F and H-type primary reducers and main gear housing)
- Special coating
- Oil temperature switch
- Oil level switch
- Explosion proof switches