In the realm of food processing, the production floor often resembles a whimsical landscape, with conveyor tubes snaking through machinery in a manner akin to stepping into a Dr. Seuss illustration or the enchanting world of Willy Wonka’s Chocolate Factory.
For the uninitiated, even seasoned industry professionals may struggle to discern the type of conveyor tubes they encounter—whether they are screw (auger), pneumatic, vacuum, aeromechanical, tubular drag chain and disc, or tubular drag cable and disc—unless they are plant engineers or maintenance personnel. Indeed, many specifiers, architects, engineers, and other professionals lack in-depth technical knowledge or practical experience with these conveyors.
This lack of understanding can lead to dire consequences when delicate materials or precise blends need to be conveyed reliably. Instead, costly product destruction or inaccurate blends may occur.
This article will focus on misconceptions regarding tubular drag cable and disc conveyors, addressing six prevalent viewpoints within the industry.
Tubular drag cable conveyors gently propel products through a sealed tube using a coated, flexible stainless steel drag cable that loops through the system. Solid circular discs (flights) are attached to the cable, pushing the product through the tube without the need for air. These conveyors excel in transporting delicate, precise blends of various food types in adaptable layouts and configurations.
Misconception #1: Tubular drag cable conveyors are the same as screw systems.
One pervasive misconception is that tubular drag cable conveyors are identical to screw conveyors (also known as auger conveyors). However, this is far from the truth. Screw conveyors typically use a helical blade to move granular materials within a tube, but they can cause product damage and compromise blends. As such, they are often used when material integrity is not a priority, such as in conveying food waste. The key distinction is that screw conveyors use a helical screw to move material, with the transfer speed directly proportional to the screw’s rotation speed. In contrast, tubular drag cable conveyors transport material between two discs pulled by a sealed cable, designed specifically to protect delicate products and blends.
Misconception #2: Conveyors are not designed to preserve blends and mixes.
Maintaining a consistent mix ratio is crucial when transporting blended products using a conveyor system, regardless of whether it’s a fine powder, coarse mix, or a variable-sized amalgamation of different weights and shapes.
However, traditional conveyor systems are not specifically engineered to transport blends precisely without altering the mix ratio. In open systems like bucket conveyors, various product material weights, sizes, and shapes can shift and disperse, and vibration can cause the blended product to change throughout transport. Vacuum and pneumatic systems can also cause smaller, lightweight particles in a blend to move at different speeds than heavier or larger particles, resulting in significant blend restructuring upon discharge.
In stark contrast, tubular drag cable conveyors are designed to maintain precise blend ratios, which is of utmost importance to food industry professionals. For instance, engineers have devised a completely enclosed, compartmentalized tubular conveyor system to address this issue. Based on the manufacturer’s specifications and requirements, engineers can calculate the optimal system speed, the most suitable tube angles, and the appropriate construction design to ensure that the blended product remains consistent from input to discharge, even at high volumes.
Misconception #4: Limited Space and Expansion Constraints for Conveyors
In the food processing sector, some individuals mistakenly overlook tubular conveyors, believing they can’t fit within their facility’s space or accommodate its layout, which may feature steep inclines or significant elevation changes. However, this belief is unfounded.
Modular systems, such as tubular drag cable conveyors, are ideal for complex layouts that require curves or directional changes. These conveyors can be installed at various angles, allowing them to navigate between, around, above, or below existing equipment or obstacles. This flexibility is crucial for facilities with limited space or that cannot easily relocate equipment.
Furthermore, tubular conveyors are highly space-efficient. To conserve space, the conveyor turnaround and inlet can be oriented vertically, reducing their footprint to just one foot across instead of three. Additionally, tubing can be routed through walls and discharged through the building’s roof, further saving interior space, especially when gravity-assisted discharge is feasible.
Misconception #5: Extensive Downtime for Cleaning
Traditional conveyor systems often require disassembly, cleaning, and reassembly between product changeovers, which is labor-intensive and time-consuming. In contrast, tubular conveyors do not necessitate such extensive downtime.
For dry cleaning, options such as brush boxes and air knives can be used to clean the cable, while brushes and wipers can be employed to clean the tubes. For sanitization, a sponge soaked in sanitizer can be applied without fully wetting the system.
For a more thorough cleaning, the cable conveyor’s wet cleaning process internally washes the tube through multiple steps, including a water rinse, a foaming agent, a sanitizing rinse, and a final water rinse. After flushing, urethane wipers attached to the conveyor’s discs act like squeegees to remove any residual water.
Misconception #6: Indoor-Only Installation for Conveyors
It is a common misconception that tubular conveyors can only be installed indoors. In reality, it is not uncommon to see parts of the equipment extending outdoors, particularly when conveying products from outside to inside, such as unloading raw materials from trucks or railcars, or loading finished products onto similar transports. Materials may also be conveyed over long distances, such as from a feed mill to a production or packaging room, which could be as far as 100 feet away.
When the equipment is used outdoors and the product is moist, wrapping the tubes in heat tape can prevent moisture from condensing or freezing within the tubes. Additionally, the conveyor manufacturer can provide various accommodations to mitigate the effects of wind, dust, rain, insects, and direct sunlight.
Conclusion
Tubular drag cable and disc conveyors have been meticulously designed and engineered for industrial performance, reliably conveying delicate products and blends in diverse conditions. By recognizing the true capabilities of these conveyors, food processing professionals can leverage their abilities to minimize downtime and enhance production quality.