Flexible Screw Conveyors vs Traditional Conveying Systems: A Comparative Analysis


If you work in an industrial setting, you need to transport product from point A to point B. To get your materials where they need to go, you need to invest in a conveying system.

The problem is that plenty of conveying systems are out there, and each system is optimized to meet a different need. To decide what conveying system meets your needs best, you need to do a comparative analysis.

In this article, we’re going to go over flexible screw conveyors, belt conveyors, and pneumatic systems, and compare their performance, specialties, and cost. You’ll learn what types of handling each of them is optimized for; and get advice on how to pick the best system for your needs.

Overview of Flexible Screw Conveyors

Flexible screw conveyors are used to transport product in a variety of customizable configurations. They can be adjusted to allow for different distances, angles, and flow rates to suit your system’s needs.

Parts of a Flexible Screw Conveyor

The standard makeup of a flexible screw conveyor includes an inlet, a discharge outlet, a flexible shaftless auger, a feed tube casing, a gearbox, and a motor.

The shaftless auger is the part that rotates within the conveyor to allow product to move. It comes in two different kinds of spirals, and each optimizes different features. The round spiral is used for maximum strength and flexibility, while the flat spiral is used for higher throughputs.

The inlet and outlet heads can be made from mild steel or stainless steel. For ease of maintenance, the inlet has a disconnect point that allows for quick and easy cleaning of the conveyor by reversing the screw. The discharge head also includes an inspection door and discharge spigot.

Key Features of a Flexible Screw Conveyor

Flexible screw conveyors are optimized to transfer free-flowing and non-free-flowing bulk materials, such as powder, granules, and small pellets. Their flexibility gives them an advantage in both horizontal and vertical conveying, and they require little floor space in your system.

Other Conveying Systems

Two other common types of conveyor systems are belt conveyors and pneumatic systems. Each system is designed for a different purpose and comes with its own specialties and drawbacks.

Belt Conveyors

Belt conveyor systems are the simplest material handling systems. They’re made up of two or more pulleys that drive an endless loop belt. Product is placed on one end of the loop belt and is carried to the endpoint. Belts are often made from fabric or rubber and can vary from half a foot to six feet in width.

Belt conveyors work best with large items, like packaged goods and bulk boxes. Mailrooms and airport luggage carousels typically use some form of belt conveyor.

The main appeal of belt conveyors is their simplicity. They require just one motor and a simple belt system to operate. They can start and stop automatically or have sensor-based movement. They can also vary movement speed and move products around curves.

The drawback of the belt conveyor system is that its simplicity means its application uses are limited. They work best for transporting objects from point A to point B, and can’t necessarily meet needs beyond that. They can move products up and down inclines, but the incline has a limit and still requires significant floor space. The products that a belt conveyor carries must be able to ride on the belt without sliding; parts that are rounded or prone to movement will have significant risk of falling off of the belt.

Pneumatic Systems

Just as belt conveying systems use belts to get product to its intended destination, pneumatic systems use pneumatic power to get product to its destination. They’re made up of a series of pipelines that pump air or another kind of gas through airtight pipelines. The pressure generated by the system is powerful enough to move the product for a long distance.

Pneumatic systems work best with smaller items like powders or granules that can be moved by strong air pressure.

The main appeal of pneumatic systems is their compact design. They can move horizontally and vertically with ease, and require less floor space, which allows your system to operate in smaller areas. The enclosed nature of pneumatic systems prevents the possibility of contaminants entering the system, and the atmosphere inside is always controlled. Multiple pickup and discharge points are possible, and the system can be built around pre-existing structures.

The drawback of pneumatic systems is the limitation on size. Higher product volumes can pose challenges, as most pipelines stay between 3-12 inches in diameter. The blowers and fans that create the air pressure can make a lot of noise, which requires sound enclosure or hearing protection to mitigate. Wet or fragile products won’t do well in pneumatic systems, since wet products can plug the pipeline and fragile products could be damaged in high-velocity transit.

Performance Comparison

Material handling efficiency does vary between flexible screw conveyors and other systems. Flexible screw conveyors maximize their practical efficiency via simple operation, relatively low cost, and low space requirements. They also work best with free-flowing and non-free-flowing bulk materials like powder and granules. If you’re seeking to convey powder en masse, both horizontally and vertically, flexible screw conveyors are an efficient choice.

Alternately, pneumatic systems also work well with powder and granules, but they have a limit on how much can pass through them at any one time. Additionally, fragile products are at risk of damage when passing through the sharp corners and high-pressure environment inside of a pneumatic system.

Belt conveyors are considered in a different category entirely. Perfectly suited to larger products and packages, belt conveyors are the champions of taking things from one side of the building to the other. They aren’t the best at vertical movement since they have a limit on how steep of an angle they can be placed at, but they can steadily move product at a regular rate.

Cost Analysis

Investing in a conveyor system involves evaluating three primary costs: initial investment, operational costs, and maintenance expenses. Let’s delve into each aspect to provide a clearer understanding:

1. Initial Investment Costs:

The initial cost of a conveyor system varies based on factors such as system complexity, capacity requirements, and chosen components. Here’s a rough estimate to guide your decision-making process:

Flexible Screw Conveyor: Initial costs typically range from $4,000 for simpler setups to $20,000 for more intricate systems.

Belt Conveyor: Expect initial costs between $1,000 for basic 10-foot systems to over $50,000 for specialized long-distance conveyors.

Pneumatic System: Initial investment can range from $10,000 for straightforward systems to over $100,000 for large-scale, complex setups.

2. Operational Costs:

Operational expenses primarily include electrical usage and air consumption. Understanding these costs is crucial for long-term financial planning:

Pneumatic Systems: These systems typically incur higher operational costs due to significant air and electricity consumption.

Belt Conveyors and Flexible Screw Conveyors: With their reliance on a single motor, these systems generally have lower operational expenses compared to pneumatic systems.

3. Maintenance Costs:

Maintenance expenses encompass spare parts, replacements, and labor costs. Consider the following factors when evaluating maintenance costs:

Complexity and Moving Parts: Systems with numerous moving parts tend to require more frequent maintenance, leading to potentially higher costs over time.

Labor Cost Savings: While systems with fewer moving parts may have lower maintenance expenses, it’s essential to weigh this against potential labor cost savings, especially in today’s labor market.

Consideration of Total Cost of Ownership (TCO) in Your Conveyor System:

In addition to evaluating initial investment, operational costs, and maintenance expenses separately, it’s crucial to analyze the total cost of ownership (TCO) over the system’s lifecycle. By comparing TCO across different conveyor systems, you can make a more informed decision regarding the most cost-effective option that best suits your specific needs.

Advantages and Limitations

There are several flexible screw conveyor advantages built into the structure of the system itself. For instance, the flexible screw conveyor casing is connected to the inlet and outlet housings via pipe couplings to allow for easy assembly and disassembly. It comes in a compact assembly unit that is ready to be installed, ensuring that installation doesn’t contribute to your system’s delays.

The limitations of flexible screw conveyors are reflected in the materials that it can handle. It does best with powders or granules and isn’t designed for significantly larger products.

In terms of bulk handling systems, belt conveyors lead the field in moving product of various sizes where it needs to go.

In terms of environmental control, pneumatic systems create a pressurized environment that can be filled with air or gas, and closely regulated to prevent the possibility of external contamination.

Industry-Specific Applications

Your ideal conveying system will depend on the type of industry that you are in. Here’s a quick assortment of the major industries that each of these conveying systems work well in:

  • Flexible screw conveyors:
    • Agriculture industry
    • Animal feed industry
    • Food industry
    • Mining and mineral industries
    • Plastics and petrochemicals industries
  • Belt conveyors:
    • Agriculture industry
    • Mining and excavation industries
    • Recycling industry
    • Food processing industry
    • Transportation industry
  • Pneumatic systems:
    • Agriculture industry
    • Automobile manufacturing
    • Coal mining industry
    • Earthmoving machinery industry

Customization and Adaptability

Flexible screw conveyors have a variety of customization options available to you depending on your needs. Carolina Conveying’s flexible screw conveyors can come in both mild steel and stainless steel, and round or flat augers. We also provide options for inlet hoppers and variable speed drives, according to your system requirements.

Flexible screw conveyors can come in several different sizes, depending on your material load and optimal speed. Caroline Conveying has flexible screw conveyors in 2”, 3”, and 4.5”. With the ability to move horizontally and vertically, flexible screw conveyors can be adapted to fit into nearly any system with minimal loss of space.

Belt conveyors and pneumatic systems can also be customized, but those customizations are still in line with their capabilities. For example, belt conveyors can be customized to have more textured belts that help the product to grip the surface and prevent falling off. Likewise, pneumatic systems can’t change the fact that they run on pressure, but they can use another gas to provide the pressure instead of air.

Environmental Impact and Sustainability

The final element you should consider is the potential environmental impact of each of these systems. Traditional conveying systems weren’t designed with a focus on environmental impact, but as companies update their products and design new systems, a greener footprint is possible for your business.

When considering sound pollution and the noise levels present in your facility, pneumatic systems are at a disadvantage. Pneumatic systems use air pressure to move their product, which requires machinery to compress and move the air. Those types of fans and compressors can generate a lot of noise, which will require your facility to adapt accordingly. Belt conveyors and flexible screw conveyors that are designed to use a single motor will create less noise pollution overall.

In terms of sustainability, it’s important to note that the manufacturing industry’s carbon footprint is affected by multiple factors, but the largest of those factors is industrial rubber belting. The raw materials of rubber and oil require significant natural resources, and less than 10% of used conveyor belting is being recycled. If you decide to pursue belt conveyors, you should know that your facility’s carbon footprint is likely going to increase.

Choose the Right Conveying System for You

In the end, choosing the right conveying system comes down to your industry and your specific needs. If you need a system that takes up little floor space and can move horizontally and vertically, you might want to consider flexible screw conveyors or pneumatic systems. If you have floor space to spare and want a simple single-motor system, belt conveyors might be the right choice.

If you’re transporting powders or granules, you’ll lean more toward flexible screw conveyors or pneumatic systems, but if you’re transporting larger products or packages, belt conveyors are the way to go.

Your final points of consideration will be sustainability and cost. Decide what level of noise pollution and environmental pollution that your business is aiming for, and what your expectations for initial cost and long-term costs look like.

If you decide that flexible screw conveyors are the right choice for you, Carolina Conveying is here to help you find the perfect fit. Our products are designed to the highest industry standards and are intentionally customizable for your needs. We’ll work with you to find a custom solution that ensures your facility has high-quality performance for years to come.

Check out our flexible screw conveyors overview to see the options available to you.

To get more information about what Carolina Conveying can do for your bakery operation, contact us today!