Tubular drag conveyors are an excellent option for transferring bulk material. They are used in the food processing industry for handling fragile material products such as pet food, breakfast cereals, nuts, various snack foods, frozen foods, and more.
Tubular drag conveyors use an enclosed tube with a cable or chain running through the center with circular discs evenly spaced along the length. These discs, powered by a motor-driven sprocket, push the material forward.
Compared to other types of conveyor systems, tubular drag conveyors have several advantages, including ensuring a dust-free environment (reducing the risk of a dust explosion) and preventing foreign contamination of the product. They are also relatively easy to maintain and clean regularly.
Here’s how this conveyor equipment compares to other common conveying systems.
Tubular Drag Conveyors vs. Screw Augers
Auger conveyors (or screw conveyors) are similar to tubular drag systems in that they also convey materials through a tube. They utilize an auger inside the tube, which is a rotating, helical corkscrew-like blade that pushes granular or liquid materials forward. Auger systems reduce noise just like tubular drag solutions.
Unfortunately, screw augers are not the best choice for conveying a delicate product, especially blended materials. Because the auger blade rotates directly through the material, it causes breakage, grinding, and blend separation. This screw design is why auger conveyors are mainly used for semi-solid materials such as boiler ash, meat, animal feed, aggregates, food waste, municipal solid waste, and similar.
If you need to transport materials that require gentle conveying, a tubular conveyor is a much better option.
When it comes to facility requirements, screw augers are not as flexible as tubular drag systems. Even though they are known as “flexible screw conveyors,” because of the upward design and motion of the screw, using these conveyors in multiple planes is limited.
The higher the incline on the screw conveyor, the more power it will use. In contrast, tubular drag conveyors are quite efficient. (Especially cable systems that require minimal power, only up to 7.5 HP to run.)
Tubular Drag Conveyors vs. Aero-Mechanical Conveyors
Another tube type of conveyor, aero-mechanical systems, comprises a steel tube with a circulating rope that passes through it. Discs are evenly spaced along this rope, similar to how discs are positioned in a tubular chain or cable drag conveyor. These discs create an airstream as they move at very high speeds inside the tube.
The aero-mechanical and tubular drag conveyor solutions are both flexible and can fit almost any floor space size and layout. They are also both relatively efficient and don’t require high energy expenses.
That being said, because of the rope in their design, aero-mechanical conveyors require rope-tensioning. This adds another step in the maintenance process that increases cost and downtime. Other than that, aero-mechanical solutions are not too difficult to keep clean.
Aero-mechanical conveyors move materials at incredibly high speeds. This leads to significant product and material breakage at bends. If you want to convey fragile materials with this system, you need to maintain a slow and steady speed. Tubular drag conveyors are much more suitable for this application.
Tubular Drag Conveyors vs. Pneumatic Conveyors
There are two pneumatic conveyor types: vacuum conveyors and air pressure conveyors. The former utilizes negative conditions (a vacuum), and the latter utilizes positive conditions (air pressure) to move dry bulk materials through a fully enclosed line (a tube).
Different food products and materials can be transported via pneumatic conveyors, similar to tubular drag conveyors. Typically, pneumatic conveyor systems are used for:
- Metal powders
- Coal fines
- Food products
- Wheat flour
- Starch, and more
Like tubular drag conveyors, pneumatic solutions are flexible and can accommodate various spaces. They can even cover long distances if need be, though air pressure conveyors are better at this than vacuum ones.
A problem with pneumatic conveyors occurs when it comes to product integrity – they are known to damage delicate materials.
Filters are required for dust containment and control. These filters also need regular changing.
Furthermore, pneumatic systems need a lot of electrical power to maintain the vacuum or air pressure. They spend up to 10 times more energy than cable conveying systems. A pneumatic vacuum conveyor also generates considerable noise.
Tubular Drag Conveyors vs. Bucket Elevators
Unlike the previously mentioned systems, bucket elevators are not equipped with a tube. Instead, they have multi-sided containers (buckets) that move material either vertically or horizontally. A belt carries these buckets, with a power source driving the belt. Bucket elevators are great for transporting flowable bulk materials, such as fertilizer or grain.
However, bucket elevators are challenging to clean. A wide variety of moving parts (bolts, nuts, buckets, etc.) means that their maintenance costs are much higher than for tubular drag conveyors.
Bucket conveyors reduce noise, are energy-efficient, and don’t require a lot of driving power. That being said, they are typically not suitable for industries where sanitation and product safety (such as food safety) are important.
Tubular Drag Conveyors vs. Belt Conveyors
The distinct differences between the belt and tubular drag conveyor systems are obvious at first glance. However, given that they are one of the most common conveying systems on the market, flat-belt conveyors also bear mentioning.
These solutions consist of pulleys (two or more) that move a closed loop of material (the belt) by rotating. The pulleys are usually powered by a motor that drives the belt in the right direction.
Two types of belt conveyors are used:
- For transporting general materials (solid items, packaging, boxes, etc.)
- For transporting bulk products and materials (sand, ore, coal, grain, salt, etc.)
Even though most belt conveyors are open, they can also be enclosed to lower the chances of ambient contamination and loss of material.
Belt conveyors are used in a wide range of industries. However, they are a terrible choice for vertical material conveying. If you are looking at limited floor space and steep angles, a simple belt conveyor – even an enclosed one – just won’t do.
Furthermore, belt systems require a high initial investment and need to be carefully set up for reliable operation.
When it comes to conveying food materials and products, there are better choices than belt conveyors.
Chain vs. Cable Drag Conveyors
It is important to mention the differences between the two primary types of tubular drag conveyors as well. Not all tubular drag conveyors are designed the same – drag cable and drag chain systems come with different maintenance and cleaning requirements and different energy costs.
Tubular chain drag conveyors can compromise product integrity. They are also not the most sanitary option because food particles collect in the exposed chain, becoming a breeding ground for bacteria.
Drag chain conveyors have some routing restrictions and are not as flexible as cable conveyors. They are difficult to clean, and their sprockets need frequent replacement. They also require more energy to operate compared to cable drag conveyors.
Cable conveyors are fully optimized systems for the food processing industry. The stainless steel cable inside their tubing doesn’t collect any debris or food particles – it is sealed in a nylon jacket, making it smooth and not in direct contact with the transported material.
Unlike a chain one, a drag cable conveyor can move products in all directions – horizontally, vertically, at angles, and even around corners. They have fewer moving conveyor components than chain systems and are thus easier to maintain. Cable systems also have more wet cleaning and dry cleaning mechanism options than chain conveyors.
Finally, cable drag conveyors don’t need much horsepower to run, meaning their energy costs are lower than those of chain drag conveyors.
Determining what materials handling equipment is the best for your business depends on a series of factors:
- The material type you want to convey (particle size, flowability, stickiness, whether they are raw materials, etc.)
- Your floor size and layout
- How big your budget is – both for initial investment and for maintenance cost considerations
- Industry requirements (any special food safety or sanitation standards, and similar)
- Throughput requirements
Tubular drag conveyors are ideal for food manufacturers and food processors. Their enclosed tubular design ensures a clean working environment and prevents cross-contamination of the conveyed product. They are also more gentle on the materials than other enclosed conveying systems, such as screw augers, vacuum conveyors, and aero-mechanical conveyors.
Tubular drag solutions can be cable and chain systems. Cable conveyor systems are more in accordance with sanitation guidelines than chain ones. A tubular cable conveyor is also more efficient, flexible, and needs less maintenance than its chain counterpart.
Choosing the right material handling solution for your production facilities is a big decision. In this blog post, we’ve outlined all the basics you need to know about the most common conveying systems. If you have any more questions, please contact Cablevey Conveyors. We’re looking forward to hearing from you!