Tubular conveyors have been around for over five decades. They are crucial for a wide range of industries, including the food and beverage industry. This type of conveyor is an excellent material handling solution for a variety of fragile materials that need to be handled gently:

  • Powders
  • Pellets
  • Granules
  • Shavings
  • Flakes
  • Dust
  • Chunks, and more

Due to their design, tubular drag conveyors can be installed on inclines as well as declines, making them very versatile for any application. They transport materials horizontally, vertically, at angles, and around corners without any problems. If you wish to transport any blended materials, tubular drag conveyors can achieve this without causing separation.

Before you make the final decision about the new conveyor system for your business, here is what you need to know about tubular drag conveyors and how they work.

What are tubular drag conveyors?

Tubular drag conveyors are a type of mechanical belt conveyor that works by dragging bulk materials through an enclosed tubular space. This tubular space can be made of steel, fiberglass, or plastic, depending on the industry where the conveyor is used. The maximum conveying speed achieved with a tubular conveyor is approximately 2,000 cubic feet per hour (56.6 m3/h).

Inside the tube, discs are evenly spaced along the length of a cable or a chain. This is why there are two main tubular drag conveyor types – cable conveyors and chain conveyors. The ends of the tubular conveyor form an endless loop because they are connected to each other. The entire system is powered by a motor-driven sprocket that sits within a tube.

A tubular drag system has a modular design, allowing for changes in the number and position of inlets and outlets and conveyor length and routing.

The main benefit of these systems is that they ensure an enclosed, dust-free environment. They are ideal for the food processing industry (among others) because they prevent food contamination and reduce the risk of dust explosions and health hazards.

Tubular Chain Conveyors

A tubular drag chain conveyor has a stainless steel chain that runs through the tubing system, gently moving the product. Two types of chain conveyors correspond to the two chain types: roller and link chains. Solid circular discs (also called flights) are attached to the chain – they are the ones pushing the material through the tube.

Link chains allow for changes in conveying direction in multiple planes. They act as a universal joint, meaning a single conveyor can transport a product in different directions, depending on the need.

Roller chains, on the other hand, are not as flexible. They are made from interconnected plates and allow only one-dimensional movement.

These chains can be made of stainless or carbon steel. A tension turnaround unit maintains the proper chain tension during operation.

Because they have to meet strict FDA sanitation regulations, the chains are acid and corrosion resistant, and the guidelines for their cleaning have to be followed to a T.

This is especially true for a roller chain because food particles can become trapped between pins, bushing, and plates. Additionally, water may not drain properly after cleaning, leading to product contamination. Cleaning options for chain conveyor systems include dry cleaning and wet cleaning mechanisms.

Dry cleaning mechanisms:

  • Chain knockers – a rotating line insert that dislodges the dirt particles by knocking against the chain.
  • Brush box – also a line insert that mechanically brushes accumulated material fines off discs.

The wet cleaning mechanism consists of a three-step process that happens within the tube:

  • Foam cleaning and sanitizing – a high-foaming cleaning solution is injected into the conveyor tube to remove and sanitize accumulated particles.
  • High-pressure rinse – a water stream that washes off all materials from the inside of the tubes, including the foaming solution.
  • Dry air – Warm air is blown through the tubes to dry them. After that, the conveyor is ready to resume operation.

Tubular chain systems can convey a maximum of 80,000 pounds/h (36,287 kg/h) of a dry food product, depending on the bulk density.

Tubular Cable Conveyors

Unlike the chain conveyor, the cable system has a cable running the length of the tubular housing. It is a stainless steel cable but also sealed in a nylon jacket, making it more difficult for food particles and debris to accumulate in the cable strands.

In most tubular drag conveyors, you will find a WSC (wire strand core) cable, which is widely used in aircraft. These are incredibly high-tensile cables that will not break under normal working conditions. Their core is made from type 316 stainless steel, and it is surrounded by steel-stranded ropes.

Discs used in cable conveyors are solid and attached directly to the cable, without any bolts or screws. All of these components are easily removable for efficient and hassle-free cleaning.

Tubular cable conveyors also have more cleaning options than chain ones.

Dry cleaning mechanisms include:

  • Brush box – the same type of mechanism as in chain conveyors.
  • Urethane wiper disc – a urethane disc insert that cleans the inside of the tubing by wiping away material particles while the system is still running.
  • Air knife – a stream of high-pressure air positioned at the locations where the product is discharged from the line. This air blows accumulating fines off the cable and the discs.
  • Sponge disc and sanitizing cleaner – a disposable sponge disc that cleans the inside of the tubing with the help of a cleaning agent.
  • Bristle brush – a brush that is designed to clean the inside of tubular cable conveyors.

Wet cleaning mechanisms are similar to chain conveyors, with the main difference in the third and final step:

  • Foam cleaning
  • Sanitizing rinse
  • Water rinse – a second stream of hot water that removes the sanitizing rinse, ensuring the tube is ready for production.

Tubular cable conveyors can move a maximum of 80,000 pounds/h (36,287 kg/h) of a product, just like the chain conveyors. This depends on bulk density and the conveying tube diameter.

Cable vs. Chain Drag Conveyors

At first glance, tubular drag chain and cable conveyors might seem similar. And they are, generally speaking. But there are a few key differences you have to take into account, especially if you are looking for a conveyor system as a food processor:

  • Cost

Both cable and chain conveyors require a medium upfront investment. However, tubular drag chain conveyors have a high maintenance cost – they require more frequent maintenance and part replacement than cable conveyors. This is especially true for round-link chain systems; their sprockets tear up often, causing businesses to experience prolonged downtime and high maintenance costs.

Additionally, cable systems require less horsepower than chain ones, leading to lower operating costs.

  • Food Safety

Both tubular chain and cable conveyors are enclosed systems that prevent outside contamination and ensure a clean environment.

However, there are significant differences when it comes to the safety of the product inside the tube.

Chains have more of their surface area exposed to the product. Food residue tends to collect in the straight-angle connects, which is difficult to clean and sanitize.

In comparison, nylon-coated cables have a smooth surface without any crevices or components where particles could gather. A cable has minimal surface area exposed to the product, compared to a chain.

  • Cleaning Options

As outlined earlier, cable conveyors have a wider range of cleaning options available, unlike chain systems. This makes it easier to keep the entire system sanitary, and up to standards for the industry you’re in.

  • Strength

Cables are typically used for elevators, aircraft control systems, cranes, and bridges. They are roughly 25% stronger than chains which find their use in transportation vehicles mostly.

Even though chain conveyors are useful in specific situations, tubular drag cable conveyors are a more cost-efficient, sanitary, and versatile option.

Conclusion

Not every conveyor system is suitable for every business. However, if you are handling fragile materials, such as breakfast cereals, pellets, nuts, snack foods, and similar – you will benefit from tubular drag conveyors.

These are enclosed conveying systems that transport materials through a tube with the help of solid discs attached to a cable or a chain. The two main types of these conveyors are the tubular chain and the tubular cable conveyor.

Benefits of this equipment include contamination-free transport, a clean industrial environment without any dust particles, and flexibility. Tubular drag conveyors can adapt to pretty much any floor space, even if you have areas and corners that are too tight.

Finally, the difference between chain and cable conveyors is important when choosing the right system. With cable conveyors, you will spend less money on energy and maintenance costs. They meet all the food safety requirements – the cable that runs through the system is not as exposed to food materials as a chain is in chain conveyors. Additionally, cable conveyors have more cleaning options than chain ones.

Do you have any questions or would like more information about tubular drag conveyors? Please contact Cablevey – we’d love to set up your business for success with our Cablevey Conveyors!