Screws with a pitch spacing equal to the diameter are considered standard and are suitable for most conveyors of conventional horizontal design.
Notched Flight
Notched flights are used to provide a gentle mixing action. Notched flights are useful in blending different materials during the conveying process.
Shaftless Flights
Shaftless flights are used for extremely sticky or fibrous materials that tend to wrap around or build up on a center pipe.
Conic Flight
Conical flight centres provide a continuous incremental change in swept volume of the screw. This promotes even drawdown in a full hopper situation. Combined with variable pitch the coned screw provides the best possible solution to even hopper draw down.
Double Start Flight
Double start flights are used to accelerate the conveying process at the conveyor inlet and even out the pulsing effect at the outlet. They are also typically used in drilling and post-hole augers to equalize the torsional forces on the auger.
Notched and Folded Flights
Notched and folded flights provide a more aggressive mixing action where material that passes through the notch is lifted and mixed with the trailing material. They can also be used for aerating or cooling materials.
Hollow Flights
Hollow flights are used to pass heating or cooling liquids around the helix. Typically, both the hollow center pipe and the hollow flight are used as a heat exchanger to cool, heat or thaw the material being conveyed.
Paddles
Paddles are set in a helical form around a square or round centre tube to form a segmented spiral. They are used in mixers and pug mills to mix and condition dry products when liquid is added during the process.
Ribbon Flight
Ribbon flights with integral support legs are used for sticky or cohesive materials that tend to build up on the flight-pipe interface.
Short Pitch Flight
Short pitch screws are used in inclined conveyors. They are also used to control the feed at the inlet and to reduce flushing of free flowing materials. The shorter the pitch the more efficient is the screw.
Tapered Flight
Tapered flight spirals provide a continuous incremental change in swept volume of the screw. This promotes even draw-down in a full hopper situation. Tapered flights leave residual material in the conveyor unless the casing is tapered to suit.
Variable Pitch Flights
Variable pitch flights are used to control the amount of material drawn down along the length of a hopper. By increasing the pitch at each flight along a screw you can incrementally increase the volume of product that is allowed to enter the screw.
Canted Flights
Canted flights are used to counter the bending forces experienced when a flight is used in an extrusion process. The flight leans forward at a specific angle to the center pipe.
Wear Shoes
Bolt on wear shoes are used as a sacrificial flight tip for conveying extremely abrasive products. Wear shoes significantly extend the working life of the spiral.