Different Types of Ribbon Flighting for Screw Conveyors

Integral Leg Ribbon Screws Utilize the Post as Part of the Ribbon Flighting

Post Type Ribbon Screws Use Round Bar Posts and Ribbon Flighting

Question

I have a screw conveyor handling a wet, sticky bulk material. I want to use ribbon flighting but have heard that different types are available. What are the different types of ribbon flighting and is one better than the other?

Answer

Sticky bulk materials tend to stick to a screw where the flight is welded to the center pipe. Screws with ribbon flighting have a space within the flight and around the center pipe to minimize the collection and buildup of viscous and sticky bulk materials.

KWS designs and manufactures two types of ribbon flighting – integral leg and post type. Integral leg ribbon flights are manufactured using the same process as sectional flights and the leg is integral with the ribbon. Post type ribbon flights use round bar posts that are typically located every 90 to 120-degrees around the diameter of the pipe. Ribbon flighting is then welded to the posts to complete the screw.

Integral leg ribbon screws are more cost effective to manufacture when compared to post type ribbon screws. Additional labor is required to locate, fit up and weld each individual post and the ribbon flighting.

Post type ribbon screws work well when conveying extremely sticky bulk materials. There is less area for the bulk material to stick when compared to integral leg ribbon screws. It is also easier to replace the ribbon on the post type ribbon screws, if needed.

Post type ribbon screws provide better mixing when compared to integral leg. An inner reversing ribbon flight can be added for a better mixing effect.