A Comparative Study between L-Type and E-Type Primary Reducers
Nils Young, PE, Managing Director
|E-Type Reducers||L-Type Reducers|
|Type||Helical gearbox||Helical gearbox|
|Torque indication||Large 6” visual gauge indicating units of torque||Large digital meter indicating units of torque|
|Torque operation||In one direction||In either forward (CW) or reverse (CCW)|
|Alarm & cutoff switches||Yes||Yes|
|Mechanical torque overload Protection||Shear pin||Shear pin|
|Optional 4-20ma torque trans signal||Yes||Yes|
|Variable speed option||Yes. AC Inverter 10:1||Yes. AC Inverter. 10:1|
|Lubrication||Semi-fluid grease||Semi-fluid grease|
|Maintenance||Change every 5 years||Change every 5 years|
|Housing material of construction||Carbon steel and painted||SS 304|
|Minimal safety factor 3.0||Yes||Yes|
Advantages of the L-Type over the E-Type
The DBS L-Type torque meter is a solid-state design, highly accurate, simple and reliable. It uses a load cell to obtain the output load. The E-Type is a mechanical design which measures the torque reaction of the primary reducer. The E-Type gauge only works in one direction. The L-Type torque meter works in any direction. Torque indication could be useful when jogging the rakes lose from sludge.
Unlike the E-Type, which allows the gearbox to swivel on a shaft and bearings, the L-Type primary gearbox is fixed.
The L-Type is clean and very easy to service. It has less parts than the E-type. There are only two major components in the torque meter, a meter and a load cell. The components are easy to replace. Basic tools are all that is required. The E-Type torque gauge is a hydraulic assembly made with pressure components, fittings and tubing. Leaks are possible and the procedure to repair is challenging since it requires eliminating air in the system. Unlike the E-Type, the L-Type eliminates an adapter that includes bearings, seals, bushings, torque arm linkage, and hydraulic reaction cylinder.
Components are easier to replace. Cantilever loads applied by the weight of the gearbox and electric motor are not a design factor. The load cell housing of the L-Type has a much larger capacity to handle the lubricant expansion coming from the planetary gearbox than the E-Type. A check breather, which is installed in the E-Type is not needed for the L-Type.
The torque meter enclosure material of the L-Type is stainless steel 304 as standard. It is available as an option with the E-Type.
L-Type is less susceptible to temperature variations than the E-Type.
Advantages of the E-Type over the L-Type
Explosion proof requirement is not available in the L-Type. It is an available option on the E-Type. Power is required to operate the L-Type Torque Meter, whereas the E-Type Torque Gauge is mechanical and does not require power to operate.
Figure 1 - Model D104-GL3