In many industrial settings, particularly those involving the processing, handling, and packaging of dry particulates, buyers and sellers often face difficulties in determining the most suitable conveyor type among the myriad options available. Conveyors featuring tubes come in various forms: screw (or auger), pneumatic, vacuum, aeromechanical, tubular drag chain and disc, or tubular drag cable and disc.
Professionals such as specifiers, architects, engineers, and others may lack substantial technical or practical experience with these conveyors. This knowledge gap can lead to dire consequences when transporting delicate materials or precise blends, potentially resulting in costly product damage or inaccurate blends.
To dispel some common misconceptions and clarify questions regarding tubular drag cable conveyors:
Question: What are tubular drag cable conveyors, and how can they benefit the powder and bulk solids industry?
Answer: Tubular drag cable conveyors gently propel products through a sealed tube using a coated, flexible stainless-steel drag cable that moves in a loop. Attached to this cable are solid circular discs (flights), which push the product through the tube without the aid of air. These conveyors excel in transporting delicate and precise blends of various powders and bulk solids, offering versatility in layout and configuration.
When conveying blends of powder or bulk solid products, maintaining a consistent mix ratio is crucial, regardless of the particle size, shape, or weight. Traditional conveyor systems are not specifically designed to transport such blends without altering the mix ratio. In open systems like bucket conveyors, product materials of different weights, sizes, and shapes can shift and disperse, while vibration can further alter the blend during transport. Vacuum and pneumatic systems, on the other hand, can cause smaller, lightweight particles to move faster than heavier or larger particles, leading to significant blend restructuring at the discharge point.
Tubular drag cable conveyors, however, are engineered to maintain precise blend ratios, which is essential for quality assurance. For instance, by utilizing a completely enclosed, compartmentalized tubular conveyor system, engineers can ensure that the blend remains consistent from input to discharge, even at high volumes. Each space between the solid circular discs holds a predefined volume of product, allowing engineers to calculate the optimal system speed, tube angles, and construction design based on manufacturer specifications and requirements.
Question: Are tubular drag cable conveyors the same as screw conveyors?
Answer: A common misconception is that tubular drag cable conveyors and screw conveyors are interchangeable. Screw conveyors, also known as auger conveyors, use a helical blade to move granular materials within a tube. However, augers can potentially damage products and compromise blends, making them less suitable for applications where material integrity is critical.
Distinguishing Characteristics and Misconceptions About Tubular Drag Cable Conveyors
The primary distinction to note is that augurs transport material via a helical screw, with the transfer speed directly proportional to the screw’s rotational speed. Conversely, tubular drag cable conveyors facilitate the transfer of material between two discs pulled by a sealed cable, specifically designed to safeguard delicate powder and bulk solid products and blends.
Question: Do Tubular Drag Cable Conveyors Have Spatial and Expansion Constraints?
A prevalent misconception in the powder and bulk solid industry is that tubular conveyors cannot accommodate the available space or layout of facilities, which might include steep inclines or significant elevation changes. However, this assumption is untrue. Modular systems, such as tubular drag cable conveyors, are exceptionally suited for intricate layouts necessitating curves or directional changes.
These conveyors do not necessitate a 90-degree installation and can incorporate angles, enabling them to navigate through, around, above, or below existing equipment or obstacles. This is crucial for facilities lacking the flexibility to relocate existing structures. Additionally, tubular conveyors are highly space-efficient. To optimize space, the conveyor turnaround and inlet can be oriented vertically, reducing the footprint to one foot across, rather than three. If gravity-assisted discharge is preferable, tubing can be routed through walls and discharged through the building’s roof, thereby conserving interior space.
Question: Do Cleaning Procedures Necessitate Dismantling and Extended Downtime?
During product changeovers in powder and bulk solid handling, many traditional conveyor systems require disassembly, cleaning, soaking, and reassembly – a labor-intensive and time-consuming process. However, tubular conveyors obviate this need.
It is common for portions of tubular conveyor equipment to extend outdoors, facilitating the transfer of product from exterior to interior locations or vice versa, such as during the unloading of raw materials or loading of finished products. Tubular conveyors offer dry, wet, and in-line cleaning options. Dry cleaning can involve brush boxes and air knives for the cable, while brushes and wipers can clean the tubes. For sanitization, a sponge soaked in sanitizer can be used without fully wetting the system.
For thorough cleansing, the wet cleaning process internally washes the tube in multiple steps, including a water rinse, application of a foaming agent, sanitizing rinse, and final water rinse. After thorough flushing, drying is achieved using urethane wipers attached to the conveyor’s discs, which remove residual water like a squeegee. With an outdoor conveying system, materials can be transported from a feed mill to a production or packaging room, potentially over distances of ten to one hundred feet.
Question: Are Tubular Conveyors Solely for Indoor Installation?
Another common misconception in the industry is that tubular conveyors are exclusively for indoor installation. In reality, it is common to see parts of the equipment extending outdoors. This occurs during the transfer of powder and bulk solid products from outdoor to indoor locations, such as unloading raw materials from trucks or railcars or loading finished products into such transports. Materials can also be transported from a feed mill to a production or packaging room, spanning distances of ten to one hundred feet.
When utilizing equipment outdoors, particularly for moist products, wrapping the tubes in heat tape can prevent moisture condensation or freezing. The conveyor manufacturer can provide various accommodations to mitigate the effects of wind, dust, rain, insects, and direct sunlight.