Spiral Terminology Page
To assist you with the spiral terms that may come up in conversations, we have compiled a list of descriptions, which should help in discussing spiral issues.
Belt: The main carrying belt that is used on a spiral, can be metal, plastic or a combination. This is the belt, which comes into direct contact with the product in the spiral.
Belt Sprockets: Typically made in a plastic material, these sprockets directly engage the belt and are located near the take up drive.
Belt Stretch: Elongation of the belt due to physical wearing, not to be confused with thermal elongation.
Belt Tension: The force that can be measured on the outer edge of the belt, which is a function of the overdrive on the drum. When this tension gets too high, the outer edge of the belt wants to lift upward, causing potential problems.
Down Drum: Where the product enters the spiral at the top & exits at the bottom.
Drive Assembly: Includes the drive motor, reducer, chain and drive sprockets which are usually found either under, on top of, or outside the central drum.
Drum: The central drum or tower, which is usually a caged construction with vertical driving bars.
Drum Bars: Structural supports which run vertically near the inside edge of the belt (the outside diameter of the drum), normally a material which has enough effective force to drive the edge of the belt properly.
Drum Bar Plastic: Structural supports which run vertically near the inside edge of the belt (the outside diameter of the drum), normally a material which has enough effective force to drive the edge of the belt properly.
Expansion Point: The point where the belt changes state from a radius to a straight.
Fatigue: Usually associated with metal belt performance of structural damage due to vibrations, it is a failure of varying consequences.
Frame Assembly: The structural framework, which everything else in the spiral is attached to.
Infeed: The point where the product enters the spiral
Lubrication: Required for drive assembly, selected drive chains (where fitted), and on lubrication systems for some applications that use metal belts.
Main Drive: The central moving force that turns the drum, also called the drum drive, or drum drive.
Main Drive Chain: The chain that is used to turn and drive the central cage or drum.
Maximum Product Height: Dimensional number that should not be exceeded for proper clearances.
Outfeed: The point where the product leaves the spiral
Overdrive: Term applied to the drum speed differential as compared to the belt speed, as measured on the inside edge of the belt. In all cases the drum must travel faster than the belt.
Over Tension: When there is to much take up drive force being applied, a belt over tension occurs, decreasing belt life and possibly causing belts to flip upward on the outer edges.
Pinch Points: Any point of contact area where proper clearance is not met.
Plastic Belting: Modular plastic belting with various types and styles having specific application performance.
PLC: Programmable Logic Controller
Product Clearance: The maximum distance between the top surface of the belt and the closest support structure on the next deck or tier.
Shear Points: Any point of contact area, which can cause product shearing.
Side Guides: Pulleys or strips usually made from plastic, which help guide the belt near the infeed and discharge pulleys.
Reducer: Attached to the main drive motor, this unit allows for selected belt speeds to be obtained.
Rollers: Used throughout spirals for reverse bends of the belt, or to help guide the belt in selected areas.
Take Up Assembly: The area where excess belt is gathered and controlled automatically.
Take Up Drive: An auxiliary drive to the main drum drive, this drive acts in conjunction with the main drive to govern the tension on the belt.
Tension: A force, which is measurable either on the outer edges of the spiral belt, or on the main drive chain.
Tier: A 360° element of the spiral either ascending or descending one level.
Tier Pitch: The distance from one belt level to the next, also know as tier spacing.
Torque Limiter: A device which is typically used on the take up drive to act as a safety slip in case of a jam in the system.
Wear Strips: Plastic material placed on top of the belt rails, for decreased friction on the system.
Under Tensioning: A state where there is too little drive force being applied to the drum/belt interface causing uneven belt surging.
Up Drum: Where the product enters at the bottom of the spiral & exits at the top.
Vertical Wear Strips: Plastic wear strips, which are attached to the vertical supports to interface with the inside belt edges. |
