More about our custom spirals here.

Acetal POM (polyoxymethylene). DuPont trade name Delrin. The most common type of plastic used in spirals with plastic conveyor belts. High strength, low friction and good dimensional stability.
Auxiliary Drive Drive that helps pull the belt and keep it tight on the drum. Normally it turns drive sprockets located in the take-up.  Can be a second motor or chain driven by the main motor. (aka Tension Drive)
Bar Caps Wear strips, typically made of UHMW, installed on the cage bars.
Belt Rails Structure that the belt rides upon.  Typically consist of stainless steel bars or tracks covered with UHMW wear strips. Minimum of 2 rails, more for wide belts.
Btu The British Thermal Unit is a traditional unit of energy. Equal to about 1055 joules. It is the amount of energy needed to heat one pound of water one degree Fahrenheit.
Cage Large, cylindrical core of the low tension style of spiral system.  The system’s primary drive component. (aka Drum)
Cage Bars Vertical members of the cage system that form the driving surface. Usually stainless steel square tube.
Cantilever Horizontal structural member with one end attached to a column, and the other end free.  The outriggers that support the belt rails are cantilevers.
Christmas Tree Condition resulting from excess tension in the belt around a curved path, causing a bowed belt edge.  This term tends to be used inconsistently in the industry.
Column Structural member of the spiral system that forms the primary support for the skeleton. Columns are arranged circumferentially around drum.
Condensing Unit The outdoor refrigeration equipment used to transfer heat out of the refrigerant fluid. A condensing unit includes compressors, condensing coils and fans. They may be air or water cooled. (aka Con-U)
Connector Rod Wire or rod that is usually of the same material as the belt, used for connecting belt sections.
Cross over Length of the straight-running belt that travels from the center of one spiral to the center of another in a two-cage, one belt system.
CCW Counter-Clockwise, when viewing spiral from above.
CW Clockwise, when viewing spiral from above.
Dancer Roll Weighted roll at the bottom of a take-up loop.
Down Spiral Describes a spiral system in which the belt travels from an upper to a lower level in operation. (Down cage, Down-go)
Drum Large, rotating cylindrical core of the low tension style of spiral system. The system’s primary drive component. (aka Cage)
Dwell Time The amount of time a product takes to travel through the spiral.
E Stop Emergency Stop
Extended Sidebar Chain A retaining edge provided by special attachments on the chain.
Flip-up Condition resulting from high tension, which causes the outside edge of the belt to raise off of the supports.  The inside belt edge remains up against the drum.  Sometimes referred to as a Christmas Tree problem.
Freon A commonly used term for synthetic refrigerant CFC or HCFC fluids. Strictly speaking this is a brand name for a CFC refrigerant (R-22) that is discontinued due to its impact on the ozone layer.
Hold Downs Structural members which limit the amount that the belt edge can rise.  Down spirals require hold down rails on the inside edge to keep the belt from riding up on the drum.  On the outside edge hold downs may be used used to reduce flip up effects.
HMI Human Machine Interface (often refers to a touch screen)
Infeed The starting straight section of belt leading onto the spiral. (aka Inlet)
Inside Drum Radius Distance from the rotational axis of the drum or cage, to the driving surface of the drum.
Inside Turn Radius Turn radius measured to the inside edge of the belt.
IP(#) Ingress Protection rating. To indicate washdown resistance level of electrical components. eg IP66 (suitable for water jets)
Lane Dividers Detachable plates assembled into the belt’s width in order to provide separate lanes for product travel.
Limit Switch Switches installed to sound an alarm when the dancer roll travels too high or low, indicating tension malfunctions. (proximity switch, prox switch)
Linear Loading Density The weight of the product distributed along the belt per length of belt. In the case of conveyor belts the units are typically shown in lb/ft (or kg/m).
Main Drive Motor, reducer, and other power transmission devices that turn the cage or drum of the Spiral (Spiral drive, Cage drive).
Mechanical Refrigeration Vapor-compression refrigeration. Distinguished from cryogenic refrigeration.
Nose Roll Machined radius plate or roller located at the conveyor terminals which the belt wraps around, allowing a close transfer.
Outfeed The final straight section of belt emerging from the spiral. (aka Discharge)
Outriggers The cantilever supports for the belt rails, mounted to the columns.
Overdrive Amount of slippage between the belt and the drum, adjusted to reduce tension. The drum needs to move slightly faster than the auxiliary drive.
PLC Programmable Logic Controller, a computer controller for industrial equipment.
Return Path Path of belt travel from the discharge port to the infeed port.
Safeties Proximity sensors that are used to monitor belt position. (Limit Switch)
Spiral Spiral is the common term but the conveyor path actually forms a helix.
SS Stainless Steel. AISI 304 is the most common variety used in food processing applications.
Straight-Thru A spiral configuration where the belt goes in one side and out the other. Infeed and discharge are located on opposite sides.
Surge This term is applied to the jerky or erratic motions of the belt caused by overdrive and differing friction of belt-contact surfaces.
Take-up Area of the conveyor system where variations in belt length are accommodated, relieving tension.
Tier The 360 degree element of a spiral, where the belt makes one full loop upward or downward along the path.
Tier Pitch Distance on the spiral from one level of belt to another.  (aka Tier Height, Tier Spacing)
TR Ton of Refrigeration. Equal to 12,000 Btu/hr. Equal to 3516.9 watts. Also called RT for Refrigerant Ton.
Turn Ratio Ratio of tightest inside turn radius to belt width. Typically 1.3 to 2.5. A 20″ 2.0 turn ratio belt can make a 40″ radius turn.
UHMW Ultra High Molecular Weight Polyethylene (a very abrasion resistant plastic)
Up-cage Refers to conveyor belt travel from the bottom of the cage to the top of the cage (infeed is lower than discharge). (aka Up Spiral, Up-go)
VFD Variable Frequency Drive – a device used primarily to control motor speed.
Walk-in Structure which insulates and controls airflow for the spiral conveyor, designed to maximize refrigeration efficiency. (aka Insulated Enclosure, Box)
90 Degree A spiral configuration in which the infeed and discharge ports are located on adjacent box faces.
180 Degree A spiral configuration in which the infeed and discharge ports are located on the same face. (aka U-shape)
270 Degree A spiral configuration in which the infeed and discharge ports are located on the other adjacent box face. The infeed and discharge are next to the same enclosure corner, unlike a 90 degree.