Principle of operation
A Flexicon flexible screw conveyor, also known as a spiral conveyor, screw
conveyor, helix conveyor or centerless 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
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
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
Move virtually any bulk material
Free-flowing and non-free-flowing materials and blends
Flexicon 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.
Only one moving part
The only part contacting material in a Flexicon 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, Flexicon 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
Flexicon 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
In addition, the gentle rolling action created by the screw prevents the
separation of blends throughout the entire length of the conveyor.
Flexible screw pioneers
Perhaps no other manufacturer has advanced the application of the flexible screw
conveyor as far and as fast as Flexicon— the first to introduce 4 1/2inch
(115mm), 6 inch (150mm), and 8 inch (200mm) diameter screw/tube combinations
that elevated the capacity of this category of conveyor more than 10-fold in an
8-year period. After more than 10,000 installations worldwide involving a gamut
of bulk materials, Flexicon has amassed a wealth of performance data on flexible
screws—many of which have been engineered, machined and formed to Flexicon
specifications. To you, it means that Flexicon has most likely solved your
problem in the most efficient and cost-effective manner possible—or can do so as
a matter of routine.