Belting Glossary

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There are 52 names in this directory beginning with the letter P.
Package conveyor
A conveyor which transports packaged, boxed, or bagged material.

Package deflector
See conveyor belt package deflector.

Packed material
Material on belting compacted as the belting moves along the system.

Performance test
See service test.

Permanent set
The amount by which an elastic material fails to return to its original form after deformation.

Permanent stretch
Elongation permanently removed from belting when it is first used.

Permeability
The quality or condition of allowing passage of liquids or gases through a rubber layer.

Physical properties
A measure of mechanical characteristics of a material.

Pick
An individual filling yarn of a fabric.

Picking idler
A short-sided troughing idler for readily removing material by hand from a belt.

Pierce tape
A woven mesh of steel wire or cord.

Pimple
A small sharp or conical elevation on the surface of a product.

Pit
A small crater in the surface of a product with width about the same as its depth.

Pitch line
The plane within a belt which undergoes neither stretching nor compression when the belt rounds the pulley, i.e., the neutral plane of the belt structure.

Plain weave
The simplest type of weave with both adjacent warp and filling yarns crossing over and under each other.

Planished cover
An irregular coated surface transformed into a smooth surface by some means.

Planished finish
See planished cover.

Plastic
A material that contains as an essential ingredient one or more organic polymeric substances of large molecular weight, is solid in its finished state, can be shaped by flow.

Plasticizer
A compounding ingredient which can change the physical and chemical properties and processibility of a polymeric compound.

Plastisol
A dispersion of a powderous polymer in a plasticizer.

Plied yarn
A yarn made by twisting together two or more single yarns.

Plows
Plates across a belt to remove material lying on or sticking to the belt.

Ply
A layer of rubberized fabric.

Ply adhesion
The force required to separate two adjoining strength reinforcing members in a rubber product.

Ply separation
Lack of adhesion between plies.

Ply tensile
The ultimate breaking strength of a belt expressed in force per inch width per ply.

Polymer
A macromolecular material formed by the chemical combination of monomers having either the same or different chemical composition.

Polymerization
The process that converts monomers into polymers.

Polyvinyl chloride
A polymer prepared by the polymerization of vinyl chloride as the sole monomer.

Porosity
The condition of containing numerous small holes or voids.

Portable conveyor
A conveyor system readily moved from one place to another.

Portable vulcanizer
A vulcanizer readily moved from one place to another, usually used for making field splices and repairs.

Pot life
The period of time during which a reacting polymeric compound remains suitable for its intended use after having been mixed with a reaction-initiating agent.

Powered roller conveyor
A term used by the U.S. Postal Service to mean a live roller conveyor. See live roller conveyor.

Press
A machine consisting of two or more heated plates which can be brought together and separated by hydraulic pressure or mechanical action.

Press cold ends
The area of reduced temperature at the press platen end.

Press lap
The area of overlap of one press cure length on the next.

Press length
The length of a belt which can be pressed at one time.

Press marks
Irregularities in the surface of a vulcanized product caused by the press ends or by corresponding irregularities in the press surface.

Press, rotary
See rotary press.

Pricker marks
Small marks in the cover of a vulcanized belt where a roll with sharp needles had penetrated the uncured belt to allow trapped air in the uncured belt composite to escape.

Processing
The operations in the manufacture of a belt.

Profile top cover
Belt surface having a series of continuous or interrupted, straight or curved ridges, across the belt at regular intervals to enhance the belts ability to move materials up inclines or down declines.

Prong
The sharp point of a mechanical fastener that penetrates the belt.

Pulley
A cylinder, mounted on a central axis rod.

Pulley cover
See bottom cover.

Pulley lagging
See lagging.

Pulley projection
The amount a pulley face width extends beyond belt edge.

Pulley wrap
See arc of contact.

Pure gum compound
A natural rubber or isoprene compound containing only the ingredients necessary to process it, to protect it from aging, and to cause vulcanization.

PVC cover
Cover using a PVC compound.

PVC impregnated
Impregnated with PVC compound.