Type F Primary Reducer Provides Uninterrupted Service, Ease of Maintenance, and Accurate Torque Outputs in Harsh Environments

By Nils R. Young, PE, Managing Director


DBS developed its new F-type hydraulic primary reducer to help clarifier and thickener drives achieve a new level of reliability in harsh environments. The self-contained, multi-function mechanical speed reducer transmits power from the electric motor to the secondary gear reducer on DBS clarifier and thickener drives. This F-type hydraulic primary reducer also provides positive torque overload protection to your clarifier or thickener mechanism. Built specifically for continuous harsh environmental equipment service and reliability, this reducer can efficiently take the place of the gear motor, chain drive, and torque overload switch assemblies typically found on other brand thickener drives.


The DBS F-type reducer consists of an electric motor driven gear pump, high torque low-speed hydraulic motor, pressure sensing devices, directional and relief valves, filtration, and manifold assembly. These working components come neatly packed inside a specially designed steel housing, which also serves as the fluid reservoir.


Normally driven by an 1800 or 1500 RPM electric motor, the positive displacement gear pump converts rotary shaft power to fluid horsepower. Within the F-type primary reducer, this fluid power from the pump passes across the manifold, where it is directed to the positive displacement hydraulic motor. The hydraulic motor converts this fluid power back into rotary shaft power at a much higher torque and lower speed. The F-type reducer provides a wide range of speeds through a variety of hydraulic motor and pump displacement combinations. Single direction rotation is standard. Dual direction rotation and variable speed are available.


What makes DBS Positive Torque Overload Protection so accurate and safe? The drive unit shaft output torque is directly proportional to hydraulic motor working pressure. The DBS torque gauge mechanism also provides accurate output torque indication. This system is simple, easy to adjust and understand, with torque indication outputs that include both a large visual gauge at the drive, up to four independent preset torque level switches, and optional 4-20mA torque (pressure) transmitter.


These pressure-sensing devices are connected to the manifold and indicate the scraper mechanism torque load. This gives operators an accurate local visual indication of output torque, high torque alarm capability, high torque drive cut-off capability, and 24VDC analog torque output capability.


Positive torque overload protection is a key advantage with the F-type reducer. Alarm and cut-off torque switch settings are variable to fit each customer's specific application. The torque overload switches are ruggedly enclosed for severe service, yet easily adjustable and precise. Should the torque switch controls be overridden and the drive loaded past the stall torque setting, the F-type hydraulic reducer will reliably slip or stall to protect your clarifier mechanism. Stall torque is factory set to customer's design requirements. The typical mechanical shear pin feature found on many other thickener drives has been functionally improved upon, by the simple stall safety feature inherent to DBS hydraulic transmission designs.


The DBS housing design has no open rotating shaft seals. This design eliminates much of the shaft seal replacement maintenance common to conventional gear motor primary reducers. There are no open moving parts such as sprockets, chains or shafts on the DBS F-type Reducer, so there are fewer power transmission components to lubricate and maintain.


These self-contained hydraulic primary reducers come in 6- and 10-gallon sizes. Sizing depends on application horsepower requirements. DBS engineers are fully prepared to help with sizing a unit to best fit your needs. DBS F-type reducers typically use standard mineral base 10W, ISO 32, hydraulic oil, and have an easy-to-change oil filter located on top. This feature allows the system to continuously clean itself, and reduces oil changes that would otherwise be needed with comparable gear motor drives.


In addition, DBS units are 100 percent pressure leak tested. They have no external hydraulic hoses or piping. All lines and connections are sealed and then self-contained within the F-type reducer enclosure. DBS F-type reducer continuous mechanical service factor is 3.0 minimum throughout.


So when uninterrupted service, ease of maintenance, and accurate torque output is what you want, the self-contained F-type hydraulic primary reducer may be what you need. For more information, call DBS Manufacturing at (404) 768-2131.