Flexible screw conveyors are one of the most common types of conveyors used by manufacturers because of their low cost and simple construction.

Although it isn’t a complicated piece of equipment, and is still reliable with a straightforward operation, many users fail to see important factors that could possibly lead to poor performance, excessive power usage, severe wear, and material degradation. These factors all make it vital that you consider all system parameters when reviewing conveyor options.

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The flexible screw conveyor has a helicoid screw that rotates inside a tube. Screw conveyors typically range from 2 ½ inches to 8 inches and can be used for horizontal transports of up to 80 feet, and inclines of up 60 degrees. The screw, otherwise known as the auger, inside of the tube is stainless steel and is available in round, flat, square bar, and beveled edge configurations to fit each application.

Material Characteristics

Flexible screw conveyors can move many types of materials, such as powders, crystals, flakes, granules, pellets, and irregular shapes. However, you still need to consider how the material will affect the conveyor, as well as how the conveyor might affect the material. For example, paying attention to how salt, or similar materials behave in the conveyor. These materials can cause friction which can lead to the particles becoming crushed, heated, or chipped during transport.

Flexible Screw/Auger Types and Characteristics

With the flexible screw conveyor there are many different auger designs to choose from that would be best for your application, depending on the characteristics of your material. The different auger types are: flat wire, beveled or square bar, and round wire. There is also what is called the centercore which is a small tube placed on the center of the screw that extends the full length of the auger. It reduces the load imposed on the screw by taking up more room in the tube, and restricting the amount of material allowed to enter the conveyor.

Flow Rate

Based on type of auger used, auger’s rotation speed, configuration of the feed hopper and tube, material’s flowability and overall characteristics, and conveyor’s angle of incline, the flow rate can be increased or decreased.

Capacity and Power Requirements

There are many factors that can affect capacity and power requirements; the most common are: material particle size, material bulk density, material flowability, conveyor length, auger rotation speed, conveyor diameter, helicoid pitch, and conveyor incline angle.


Although there will be some residual material in the inlet tube once the hopper is empty, there is a way to clean your flexible screw conveyor. To do so, remove the end cleanout cap at the bottom of the conveyor and reverse the rotation of the screw.

Another option, exclusive to Hapman, that is perfect for applications where all the material needs to be thoroughly cleaned out of the conveyor with an easy disassemble and easy clean, there is the Hi/Lo. It is a tilt-style flexible screw conveyor that makes for easy wash-downs, cleanouts, and auger changeovers.

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Flexible screw conveyors are definitely a cost effective, dependable choice for conveying a wide-range of materials. They are rugged, yet simple and they keep maintenance low while providing a user-friendly, reliable operation.