Screw Conveyor – The Efficient Way to Convey Bulk Materials

A screw conveyor is an efficient way to convey bulk materials. They are ideal for thermal applications, corrosive and mildly abrasive applications.

Proper helical screw conveyor design requires knowledge of the bulk material being handled. The Conveyor Equipment Manufacturers Association (CEMA) provides material classification codes for the majority of bulk materials.

Flexible Design

Unlike other conveyors that can only convey materials in one direction, a flexible screw conveyor can transport material both forward and backward. The flexibility also allows it to navigate around obstacles such as corners, pipes and other machinery, unlike other systems that require special mountings to be able to work.

Despite this flexibility, they can only be used to transport certain materials because of the inherent tumbling and pinching of the material between the screw flight and trough. They are also not ideal for fragile materials as screw conveyor they can be damaged. They are also not suitable for sanitary or food grade applications as their design leaves too many gaps and surfaces that sticky materials can get hung up on.

The design of the screw flight “pig tail” is another important factor in determining which types of materials can be transported. Round designs are the most common, although profiles with a flat spiral exist. The manufacturer is usually able to select the profile that gives the best transport, based on data acquired earlier or through pilot plant trials.

The capacity of a flexible screw conveyor can be limited by several factors such as the angle of inclination, rotational speed and power requirements. It is recommended that a test be performed to determine the specific power required to maintain consistent conveying capacity.

High Capacity

Screw conveyors are ideal for transporting bulk materials at a high rate. They can handle a wide range of applications in many different industries. Their use is often seen in wastewater treatment systems where they help transport sludge. They are also used in agriculture to transport fertilizers to gardens. This equipment can also be found in mining and concrete production, where it helps move the material efficiently.

In a typical screw conveyor, materials are loaded into a casing or tube where they remain entrained between the screw blade (or ‘flighting’) and the helical shaft. When the screw is rotated, the material moves from the trough to the point of discharge, where it is either dropped or transferred into another container such as a silo or storage area.

To ensure maximum capacity, it is important to select a screw conveyor with the correct diameter. A simple calculation takes into account the load, screw diameter, and shaft speed to determine the conveyor’s capacity. The result is usually expressed as the number of cubic feet of load per hour that can be conveyed with one revolution of the screw.

In most industrial applications, it is a good idea to limit the maximum screw conveyor speed. This will reduce the amount of friction and compression that is added to the screw. In addition, the higher speeds increase wear on the screw and shaft.

Low Maintenance

Designed for efficient performance, these conveyors provide an exceptionally wide range of material transport capabilities. The only moving part that contacts the material is a flexible inner screw, minimizing maintenance and downtime. They are easy to clean and can be adapted to work in low headroom areas.

The screw conveyor is a device for conveying bulk materials, which is capable of handling a variety of substances that have relatively good flow ability. Flow ability is a term that finds its origin in CEMA material classification standards and refers to the freedom of individual particles of the substance to move past each other. This is possible due to the helix blade (or flighting) mounted on a central shaft, rotating within a fixed trough or tube and pushing the materials along.

A conveyor can be made to include multiple points of discharge, valves and side gates. This allows the material to be directed in various directions and minimizes waste. It also helps to reduce environmental impact, since the conveyor prevents spillage from occurring.

Although the conveyor is fairly low maintenance, there are some components that may need to be checked and replaced from time to time. For example, the suspension bearings may need to be replaced. This should be done by lifting the cover of the conveyor and making sure that it is blocked from power before doing so.

Easy Installation

A screw conveyor’s installation vacuum packing machine suppliers process is simple compared to many other material handling solutions. A skilled technician can install the screw conveyor quickly to reduce downtime for businesses. The conveyor can then be tested for optimal performance and to ensure it moves materials correctly.

A shaftless screw conveyor uses adjustable paddles positioned helically across a pitch to aggressively mix bulk material. This type of conveyor requires less maintenance and provides greater mixing action than other types. It’s also ideal for high moisture content applications because it won’t clog.

The shaftless conveyor doesn’t require a center shaft or hanger bearings, which helps reduce wear and increases efficiency. The helix can be configured to achieve an average fill rate of 30% to 45%. On dewatered sludge apps, it’s often better to lower the fill rate to be conservative when sizing the equipment.

The screw conveyor should be started without load and fed slowly after the initial start-up. This will prevent the screw conveyor from clogging and overloading the drive system. The conveyor should be inspected periodically and lubricated as needed to keep the moving parts in proper working condition. This is particularly important for heavy-duty applications like mining or concrete industries. Adding these routine checks to a preventative maintenance plan can help reduce downtime and prolong the life of the conveyor.