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Fequently asked questions regarding screw feeders, flexible screw conveyors, FIBC dischargers and auger screws.

What is a metering screw feeder, and what are they used for?

Metering screw feeders use a series of mechanical and electronic components to meter and control the flow rate of dry bulk materials such as grains, powders, and pellets. Consisting of two critical moving parts, the optional agitator and auger screw, screw feeders are relatively low maintenance and easy to clean. The agitator is positioned inside the conditioning section, continuously rotating to prevent bridging, rat-holing and blockages, which can occur when dosing poor-flowing and sticky materials. The auger screw is positioned below the agitator at the bottom of the feeder’s body, rotating at a set speed, moving the material between the screw flights forward from the feeder to the next part of the handling process.

Screw feeders are incredibly versatile, used in thousands of applications, from food to pharmaceutical processing lines, and are easily integrated into almost any bulk material operations. There are three types of screw feeders, volumetric, gravimetric, and micro, which are manufactured from either mild steel or stainless steel 314 or 316, therefore, capable of withstanding harsh and corrosive environments. At Trantec, we manufacture metering screw feeders in various configurations to suit all types of applications, supplying to all industries, from plastics and food to chemical.

What is the difference between volumetric and gravimetric screw feeders?

Both gravimetric and volumetric screw feeders are engineered to provide high accuracy and reliable dosing. The primary distinction between the two lies in their operation and features. Gravimetric feeders are equipped with weighing cells and are the preferred choice for handling difficult-to-manage materials. These feeders offer advanced monitoring and reporting options, as well as self-calibrate, dosing the material until the required target weight is achieved. This ensures consistent and precise dosing without the need for manual intervention. In contrast, volumetric screw feeders require manual calibration to ensure the correct material mass is dosed over a set period. While they are effective and reliable, they do not offer the same level of automation and precision as gravimetric feeders.

For a comprehensive comparison of gravimetric and volumetric screw feeders, including their specific features, benefits, and applications, please visit our detailed comparison page.


When do you need a screw feeder for positive control?

A screw feeder is an indispensable piece of equipment in any industrial process that requires precise, positive control of dry bulk materials. Positive control is exceptionally beneficial when the material being fed is challenging to handle to ensure that the exact amount of material is dispensed accurately, especially in applications where precise timing is critical.

What is a flexible screw conveyor?

Flexible screw conveyors, also known by various names such as flexible spiral conveyors, auger conveyors, and helix conveyors, are renowned for their versatility and efficiency in transporting bulk materials across a wide array of industries and applications. These conveyors are designed to handle a broad spectrum of materials, ranging from fine powders to grain and large granules, making them indispensable in numerous industrial processes.

How does a flexible screw conveyor work?

Flexible screw conveyors are a versatile solution for material handling, comprising of a stainless-steel helical screw or spiral enclosed within an ultra-high molecular weight polyethylene tube, a motor and a gearbox. The ingenious design allows for seamless movement of materials from the inlet to the discharge point as the screw rotates, exerting a directional force within the tube. This gentle yet effective mechanism ensures smooth and controlled transportation of various materials, making flexible screw conveyors ideal for a wide range of industries and applications.

What types of material can a flexible screw conveyor move?

With their adaptable design, flexible screw conveyors find application across diverse industries, facilitating the conveyance of materials ranging from free-flowing to poor-flowing and non-free-flowing. However, it’s crucial to assess the material beforehand to ascertain the appropriate conveyor configuration, as certain materials may pose handling challenges. By evaluating material characteristics and considering factors such as flowability and particle size, the optimal conveyor setup can be determined, ensuring efficient and trouble-free material transport.

What is a flexible screw conveyor tube made from?

Flexible screw conveyors feature a hollow outer tube crafted from UHMWPE (ultra-high molecular weight polyethylene). This material is widely recognised as the gold standard among flexible screw conveyor manufacturers across the globe, thanks to its unparalleled quality and exceptional properties of UHMWPE, making it the ideal choice for demanding industrial applications.

How to clean a flexible screw conveyor?

Trantec flexible screw conveyors have a removable cap (also known as an end bung) positioned at the end of the inlet point. Once removed, this permits rapid and problem-free emptying of the conveyor tube. Reversing the rotation of the screw help to evacuate any remaining residue before flushing with water, chemicals or air. The flexible screw itself can be swiftly removed for a thorough cleaning by simply removing the outlet lid and undoing the motor adaptor pins to release the spiral/screw.   

What are FIBC bulk bags?

FIBC stands for flexible intermediate bulk containers. FIBC bulk bags, also known as super sacks, are made from strong, flexible fabric and are intended for industrial use of storing, shipping, and transporting dry bulk materials such as granules, plastics, pellets, and fine powders. They come in various shapes and sizes and hold a range of weight capacities. The most common FIBC bulk bags are conical, spouted, disposable, and single-trip.

How should the FIBC be positioned during the discharging cycle?

Specific steps must be taken to ensure the complete and safe handling of FIBC. FIBC dischargers are supplied with a lifting frame attachment known as a cruciform. The loops of the FIBC should be hooked over the loop carriers on the cruciform and secured correctly. The cruciform is then lifted by a crane, hoist or forklift truck into position. When the FIBC is hung by their loops when lifting onto the discharge frame, it is typical for the FIBC bag to sag to some extent. However, as long as the cruciform is positioned correctly onto the top of the discharger frame, the bulk bag should be sat centrally on the tundish (square dish section that the bag sits on).

What are the features of a bulk bag discharge system?

To list a few, FIBC dischargers are versatile in design. They can be manufactured with an adjustable heightened frame to facilitate various sizes of bags/sacks and are compatible with a wide range of FIBC sack types, from spouted to conical. Split-frame dischargers are also available to accommodate low headroom areas with restricted heights. Bulk bag dischargers are also relatively simple to install, quiet in operation, and offer non-problematic cleaning to keep downtime to a minimum. To promote dust-free unloading of materials that tend to become airborne, air-tight rubber membrane seals are used or features such as a dust containment box or connection to a dust collection system. For more information on Trantec FIBC discharger, please click here. 

What is an auger screw

An Archimedes screw, commonly known as a auger or helical screw, is a versatile tool with a history dating back centuries. This spiral-shaped device plays a crucial role across various industries due to its ability to efficiently transfer and deposit materials. Historically, augers have been fundamental in diverse applications, from ancient irrigation systems to modern industrial processes, and are indispensable in the bulk solids industry, being a key component in equipment such as metering screw feeders and rigid conveyors that help manage the flow of materials with precision and reliability, making them essential in operations ranging from agriculture and food processing to mining and waste management.

What is an auger flight?

An auger flight is a spiral blade that rotates and moves loose material from one point to another. Auger flights are manufactured in a wide range of configurations, from notched flighting and tapered to double flighted, depending on the characteristics of the material being handled.

How does an auger screw work?

An auger, also known as a helical or Archimedes screw, operates on a simple yet effective principle to transport materials. Auger screws consist of a central core shaft and helical flights surrounding the shaft. As the auger rotates, the flighting turns, which transport the material up the flights one flight per rotation, to carry the material along the length of the auger to its destination.

How to make an auger screw?

Auger screws are constructed in various materials depending on the application requirements. Material of construction can include mild steels, stainless steels 303, 304, and 316, and engineering plastics, such as UHMWPE (ultra-high molecular weight polyethene). Depending on the auger’s configuration and the application requirements, augers screws are either welded and fabricated, machined, or a combination of the two. At Trantec, we manufacture our augers using advanced CNC (computerised numerical control) machines. However, if complete machining is not feasible, we manufacture hybrid augers, created using both CNC technology and manual fabrication methods, to produce premium-quality augers.

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