Pneumatic Conveying vs Tubular Cable Conveyors

When it comes to moving bulk materials, pneumatic conveying and tubular cable conveyors are two solid options for transportation. 

Your decision between these two systems should be based on the specific characteristics of your material and your overall goals. Factors such as product fragility and density come into play, as well as the layout of your facility, the distance materials need to be moved, and your budget.

Read on to find out how these two systems differ, the pros and cons of each, and how you can decide what’s best for you. 

Pneumatic Conveying

Pneumatic conveying systems move materials through pipes with either positive or negative air pressure. This high-velocity method is often used for powders and granules, such as flour, whole grains, plastic pellets, and pet food. 

In many of these systems, rotary positive displacement blowers, or PD blowers, create a pressure differential and drive the air that carries these materials. Through changing the air pressure and creating either pressure or vacuum, products can be swiftly moved.

Key Advantages 

• Flexible Routing: Because the material is transported through pipes, you can easily route it around corners, at a vertical angle, or over long distances that would be impossible with mechanical conveyors.
• Dust Control: The system is completely enclosed, which almost entirely eliminates dust emissions and helps to keep your facility clean.
• Low Mechanical Maintenance: There are very few moving parts within the pipeline itself, reducing the need for mechanical repairs.
• Cleaning: These systems are easy to clean, making them a solid option for food-grade or chemical applications where cross-contamination should be avoided.

Potential Disadvantages

• High Energy Consumption: Because it takes a significant amount of power to move material with air, the system can be more expensive.
• Material Damage: The intense air pressure can lead to fragile materials being broken or damaged. It can also cause stringy plastic or pipe erosion if the material is abrasive.
• Filter Management: It requires robust dust collection and filtration systems at the discharge point.

Tubular Cable Conveyors

A tubular cable conveyor is a mechanical system that uses a coated stainless steel cable with circular discs, or flights, attached at regular intervals. In this system, the cable pulls the material forward through a tube at a much lower velocity.

It can have multiple inlets and outlets, and like pneumatic conveying systems, it is also fully enclosed. This system is ideal for materials that tend to be more delicate or fragile, such as nuts, cereals, trail mixes, or coffee beans.

Key Advantages

• Gentle Handling: Due to the slow speed at which the material moves, breakage rarely occurs during the transportation process. 
• Energy Efficiency: These systems use small motors (often less than 5 HP), which means that they are much cheaper to run than pneumatic systems.
• Maintains Blends: If you are moving a pre-mixed product such as trail mix, the cable conveyor prevents the ingredients from separating by density.
• Quiet Operation: Tubular cable conveyors are much quieter than high-pressure blowers.

Potential Disadvantages

• Mechanical Wear: Due to friction and tension, the cable will eventually stretch and need to be adjusted or replaced.
• Distance Limitations: Though they are able to move materials around corners, they cannot move things over vast distances like pneumatic systems can.
• Wet Material Issues: Substances that are wet or sticky can build up on the discs and cable, making cleaning difficult.

Which is Right for Your Needs?

Because each system has its own benefits and drawbacks, you will want to consider factors such as material density and strength, facility layout, budget constraints, distance needs, and routing and maintenance goals.

Consider the following examples:

• If you needed to move 50 tons of flour per hour across a factory, pneumatic conveying would likely be your best option due to the volume of material and the routing flexibility you would have.
• If you wanted to transport roasted coffee beans or granola, a tubular cable conveyor would be best because it would preserve the integrity of your product and use far less power.
• If you were trying to move highly abrasive material, a pneumatic conveying system with specialized elbows might be easier to manage than a mechanical cable that could wear out quickly.

Comparison Summary

To sum up, pneumatic conveying is a better option for longer distances, higher speeds, increased routing flexibility, and strong materials, while tubular cable conveyors are great for fragile or pre-mixed materials, as well as for conserving power and limiting noise. 

Take a look at this summary of the key differences between the two:

Reach out to the Northwest Flow Technologies Team

If you determine that pneumatic conveying makes sense for your materials and business needs, our team at Northwest Flow Technologies would love to help connect you with the right products. 

We distribute the MD-Kiney brand of M-D Pneumatics® PD blowers, which are integral to pneumatic conveying systems. PD blowers and blower packages are available, with options for different models and features. We also offer PD blower repair services, aiming for efficiency and quality so we can best support our clients. 

To learn more about what we offer or for questions about pneumatic conveying and tubular cable conveyors, reach out to us today.