Screw

Screw Conveyor Systems

Screw conveyor systems contain a large screw located inside of tubular housing. When the screw is turned by a motor, the material rotates along the screw thread and is transported down the length of the screw.

Screw conveyor systems can be flexible or rigid in design. A flexible screw conveyor differs from a rigid screw conveyor in that it is capable of bending to some degree. This feature means that the conveyor system takes up less space than rigid conveyor systems.

Screw conveyor systems are designed to transport small grained materials, such as grain and plastic pellets used in injection molding. Depending on the application, screw conveyors may be fitted with a variable rate feeder to control the amount of product distributed at each time. Unlike traditional belt conveyors, screw conveyors are capable of transporting liquid products. However, they are not as efficient as other fluid moving methods, as some water usually leaks out of the screw and runs back down the tube.

Screw conveyor systems are widely used in agricultural applications. In these cases, the machine may be referred to as an auger conveyor. Auger conveyors, often equipped with a chute attached to one end of the conveyor to direct the path of the grain, are extremely useful in filling silos with grain.

A.	Conveyor Screw
B.	Job-Rated Components Jig-Drilled Couplings, Tem-U-Lac Self-Locking Coupling Bolts
C.	Hangers and Bearings
D.	Trough Ends
E.	Troughs, Covers, Clamps and Shrouds
F.	Nu-Weld® Flange
G.	Feed and Discharge Spouts
H.	Supporting Feet and Saddles

TL Screw Conveyor Drive Components

Principle of operation A flexible screw conveyor, also known as a spiral conveyor, screw conveyor, helix conveyor or center less auger conveyor, consists of a spring steel or stainless steel, flexible screw that is enclosed in a flexible or rigid plastic tube, or a rigid steel tube, and driven by an electric motor normally located at the discharge end of the conveyor. This simple design delivers efficient performance and high reliability while reducing maintenance and cost. When properly engineered according to the specific characteristics of the material being conveyed and the process into which it will be integrated, a flexible screw conveyor can outperform rigid screw conveyors, bucket elevators, drag chain conveyors, aero mechanical conveyors and other equipment intended to transport powder and bulk solid materials. The intake end of a flexible screw conveyor tube is typically equipped with a charging adapter a U-shaped trough that connects to the outlet of a hopper or directly to the outlet of process equipment such as a bulk bag discharger, bag dump station, grinder, crusher, screener, blender, reactor or storage vessel of any kind. The flexible screw passes through the charging adapter trough, exposing a section of the screw to material flowing into the trough from above. When rotating, the exposed section of screw feeds material into the outer tube, where it is then propelled through the tube by the enclosed portion of the screw. A phenomenon resulting from the loose fit of a rotating flexible screw within a tube filled with bulk material, is that the screw automatically self-centers within the tube, providing clearance between the screw and tube wall. This affords sufficient space for particles to flow without damage, depending on the fragility and size of particles being conveyed. A removable clean-out cap covers the intake end of the conveyor tube, permitting rapid emptying and flushing of the tube, as well as disassembly and wash-down of components. Because the intake end of the screw requires no bearing, and since the discharge end is coupled to the motor drive above and/or beyond the point at which material exits the discharge spout, material does not come in contact with seals or bearings. The flexible screw is therefore the only moving part contacting material.   Move virtually any bulk material Free-flowing and non-free-flowing materials and blends Flexible screw conveyors offer efficiency and versatility, conveying bulk materials ranging from large pellets to sub-micron powders—both free flowing and non-free-flowing—with no separation of blended products. For moist, sticky, friable or other difficult-to-handle materials that pack, cake, smear, plug or breaks apart. Only one moving part The only part contacting material in a flexible screw conveyor is the rugged flexible screw, which is driven by an electric motor. As it rotates, the screw propels material and self-centers within the conveyor tube, providing constant clearance between itself and the tube wall. This simple design does not require cables, chains, disks, internal bearings, and numerous moving parts found in bucket elevators, rigid augers, drag chains, and/or aeromechanical conveyors—parts that can add initial cost, require maintenance, wear out, breed contamination, and/or break down. Convey in any direction Whereas many conveyors (such as rigid screw conveyor, bucket elevator, drag chain conveyor and aero mechanical conveyor designs) have limited angles of incline and/or straight-only conveying paths, flexible screw conveyors can move material vertically, horizontally, or at any angle—over, under, or around obstructions, through small holes in walls or ceilings. Gentle product handling and blending Flexible screw conveyors can handle your products gently, because the flexible screw self-centers as it rotates. This can provide ample clearance between the screw and tube wall to prevent grinding, crushing, and other product damage. In addition, the gentle rolling action created by the screw prevents the separation of blends throughout the entire length of the conveyor. .

Fig: FLEXIBLE SCREW CORONVEY

 

   

Applications
The AERO-FLEX is excellent for transferring most types of products including, Foods, Pharmaceuticals, Chemicals, and Plastics, from bulk bag unlades, bag dump stations, and feed hoppers.

·        Load filling machines 1 Blenders/Mixers 1 Surge Hoppers

·        Bulk Bag Loaders

·        Grinders, Pulverizes, Air Classifiers

·        Load and unload sifters

Benefits

·        Efficient transfer of material

·        Increased production

·        Simple maintenance

·        Easy to clean

·        Flexibility to meet most application and installation requirements

·        Multiple pick-up and discharge points Mobile systems for in-plant flexibility