Drag Conveyor Engineering Guide

Drag conveyors efficiently transfer bulk materials utilizing a series of fixed paddles or flights mounted to a continuous chain(s) that operate in an enclosed housing to move bulk material forward.

A motor/reducer drives the head shaft sprocket. The sprocket pulls the chain, which carries flights spaced at regular intervals along the bottom of the housing. Drag conveyors can be utilized in horizontal positions as well as on an incline depending on the bulk material characteristics.

By conveying en masse, bulk material degradation is minimized when compared to screw conveyors. Drag conveyors typically operate with high torque and low chain speeds. As a result, chain wear and power consumption are minimized, leading to lower total costs of operation compared to other conveying technologies.

Compared to screw conveyors, drag conveyors have a higher volumetric capacity to move bulk materials. Belt conveyors have the highest volumetric capacity of all types of mechanical conveyors. Drag conveyors provide high volumetric capacity while maintaining a smaller overall footprint when compared to belt conveyors.

The use of drag conveyors, screw conveyors, or belt conveyors depends on your specific application. With extensive knowledge in bulk material handling, KWS can help choose the right conveyor for your application.

By utilizing the En-Masse conveying concept, drag conveyors transfer many different materials with very minimal product degradation. The bulk material remains static in between each flight of a drag conveyor and moves as a mass rather than being aggressively tumbled. Particle breakdown and dust generation are significantly reduced in a drag conveyor.

For most applications, drag conveyors provide reliable performance when handling a wide range of bulk materials. Proper drag conveyor design for the specific application helps minimize wear on the chain, sprockets, flights, and other key components.

KWS drag conveyors are designed to provide many years of uninterrupted service with very little maintenance. Please refer to the KWS drag conveyor engineering guide as well as the KWS drag conveyor operations and maintenance manual for more information.

Due to their low operating speeds and a chain-driven conveying system, drag conveyors can efficiently convey bulk materials over 200 feet or greater distances. Maximum conveying length depends on bulk material density, capacity, and a few other parameters. Light, free-flowing bulk materials such as grains require less power to convey over longer distances when compared to heavy, dense bulk materials such as limestone. KWS can help you with your particular application.

Each KWS drag conveyor is designed and customized to exceed the requirements of your specific application. Bulk material density, capacity, and conveying distance are some of the input parameters required for choosing the right drag conveyor for the application.

Conveyor length, chain type, liner materials, inlet configuration, discharge arrangement, and materials of construction can all be customized to meet your needs. KWS designs and manufactures round bottom and flat bottom drag conveyors for almost every bulk material from free-flowing, non-abrasive grains to dense, sluggish, cement clinker.

KWS drag conveyors can be designed to handle elevated bulk material temperatures with the appropriate materials of construction and component selections. Specialized chains, liners, and seals can be selected to suit the application’s requirements.

KWS accounts for thermal expansion and contraction in the drag conveyor design. Motors, bearings, and gear reducers are located away from the heat source to extend life and prevent premature failure.