If you’re in the business of handling dry bulk materials, screw conveyors are one of the cheapest and most effective handling methods you can use.

Screw conveyors transfer bulk materials horizontally, vertically, or at an incline. Their mechanisms use a rotating helical screw that is installed within a tube or a trough. Screw conveyors are used in many bulk handling industries, and they’re capable of moving liquid or granular materials.

To choose the right screw conveyor, you’ll have multiple factors to consider. Screw conveyors are manufactured in different shapes and sizes, and they’re not all capable of conveying the same materials.

Because there’s no ‘one size fits all’ solution, we’ve compiled this guide to tell you all you need to know about screw conveyors so that you can choose the right conveyor for you.

The Different Types of Screw Conveyor

There are many iterations of the screw conveyor design. The most common types of screw conveyors are:

Horizontal Screw Conveyors

These are the most commonly used screw conveyors. They’ll typically have a drive unit at the discharge end of the machine; this causes the conveyed material to be pulled towards the discharge. This reduces tension in the conveyor’s auger sections, making the conveyor more efficient.

They’re more cost-effective than belt conveyors, and they transport materials in a linear direction, parallel to the ground.

Inclined Screw Conveyors

These conveyors are used at an incline between 0-45 degrees from horizontal. These conveyors usually require more space and power than other conveyors, but they can move materials from one floor to the other thanks to their design. Some conveyors are even portable, making them an efficient solution for many industries.

Shaftless Screw Conveyors

These conveyors are slightly more advanced than the typical screw design. They eliminate the need for intermediate shaft bearings, and there’s no need for a liner, which means they require less maintenance. They can convey wet and lumpy materials with ease, and because there’s no bottom shaft or seal, they’re ideal for pulling vertical conveyors.

Vertical Screw Conveyors

These conveyors transport materials up and down. They often require a tubular casing to hold their materials, which can also qualify as tubular screw conveyors. They’re most often used when materials need to be moved between receptacles with different heights.

Live Bottom Screw Conveyors

These screw conveyors are the best way to control the flow rate of bulk materials. These are designed to convey large volumes of materials that usually pack under pressure. They use multiple parallel screws to allow the material to be evenly discharged, even with different densities, speeds, and sizes.

Choosing the Right Specifications

To select the right screw conveyor, you’ll need to consider your industry, the materials you’ll be conveying, and the heights at which you’ll be transporting materials. You’ll need to provide your supplier with the specifications you’ll require.
Conveyor Capacity

You’ll need to calculate the volume per hour that you’ll need to be conveyed. You can do this by finding your required cubic feet per hour, selecting the trough loading percentage, finding the right screw diameter, and determining the RPM drive of the conveyor.
Trough Load, Design, and Load Type

Next, you’ll need to inform your supplier of the material you’ll be conveying. This will determine which features you need (like a trough, high dust protection, and regulated flow).
External Factors

Then, you’ll need to consider what external factors might influence your screw conveyor. This could be factors like how much distance needs to be covered, determining if the elevation will be increasing or decreasing, or if you’ll need a variable speed drive.

Partner with Experts

It’s possible to convey non-free-flowing materials, abrasives, toxins, or explosives. If you work with these materials, you’ll need to partner with an expert manufacturer to ensure your conveyor is safe and reliable. A reputable supplier can run the appropriate tests with your material to demonstrate its efficiency.