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Abrasion Resistance - a materials ability to withstand physical and mechanical actions such as rubbing, scraping, or erosion that tends to progressively remove material from its surface. Abrasion Test - establishing the rate of wearing away due to friction. Accelerated Aging - elastomer’s early change in physical properties due to intensive exposure to operating conditions. Acids - chemicals that contain pH under 7 (usually lower) like phosphoric acid, boric acid, acetic acid, sulfuric acid and nitric acid. Adhesion - the chemical bond strength between two interfaced materials. Typically these materials are rubber and steel, rubber and aluminum, etc. Adhesive Surface - an adhesive (gripping) surface used to prevent slippage of conveyed products. Aging - the process of deterioration caused by exposure to ozone, oxygen, heat, sunlight, weather, etc., resulting in changes of physical properties. Alcohols - chemicals like isopropyl, rubbing alcohol, methanol, ethanol, butanol and propanol. Anti-Static Surface - a surface that eliminates any build up of static electricity that could cause a spark.
Bare Back - the textile face of an item which is free of any covering or treatment. Bare Pulley - a pulley with no covering or lagging. Bases - chemical materials with a pH higher than 7 like alkalis, caustics, calcium hydroxide, potassium hydroxide, sodium hydroxide, sodium hypochlorite. Bed - a continuous surface over which a conveyor belt may slide. Belt Fastener - a device which holds the ends of a belt together. Belt Grade - belt classification based on belt cover quality and properties. Breaking Strength - the tensile which a textile yarn or cable, a steel cord or a belt is at rupture. Brittle Point - highest temperature at which rubber fractures upon impact.
Camber - belt curvature relative to the center line. Carcass – the fabric, cord and/or metal reinforcing section of any rubber product such as a belt, as distinguished from the rubber cover. Casting - process of pouring or injecting liquid or fluid resin mixtures into cavities or molds generally with no pressure. Solidification of the part occurs during the curing process in which the formed part can be removed from the mold. Center-to-Center - center distance – the distance between the centers of two pulleys or idlers. Chevron - a ridge or profile arranged in a V-shaped configuration. Coefficient of Friction (COF) - ratio of the force required to move one surface over another to the total force pressing the two surfaces together. An elastomer with a high COF will result in better grab than one with a low COF. Rough surface finishes will have a higher COF (better grab and traction) than smooth surfaces of like materials. Cold Flow - continued deformation under stress, characteristic of most plastic materials. Cold Splice/Bond - the joining of two or more substrates together, using a two part cement that is chemically cured without using supplemental heat from an external source. “Cold bond cement” - is an uncured mixture of varied elastomers, chemicals and solvents that will not self-cure or vulcanize until mixed with an activator to create a chemical vulcanization (usually exo-thermic). Compound - a mixture of one or more polymers and other materials which are combined to give the desired properties when used in the manufacturing of a product. Conveyor Belt Stretch - the increase in belt length which happens when tension is imposed. Core - a rigid cylinder to which an elastomeric covering or coating material is applied. Crown - the difference in diameter between the center of a roll covering and reference points at or near the ends of face. Cure - the act of vulcanization of rubber or urethane compounds or cross-linking of chemical materials. Cure Time - the time required to produce vulcanization at a given temperature. The cure time varies widely, being dependent on the type of compound used, the thickness of the cover, and the construction of the core.
Deflection - the deformation of a roll core due to its own weight and applied load. Density - mass per unit volume. Durometer - an instrument to measure material hardness. Measures the resistance to the penetration and indenter point in to the surface of rubber.
Elastomer - rubber-like material that returns rapidly to approximately the initial dimensions and original shape after deformation. Elongation - increase in length, expressed numerically as a fraction or percentage of its initial length. Esters - examples of esters include the following: ethyl acetate, cellosolve, dioctylphthalate and tricresyl phosphate. Extrusion - the shaping of uncured rubber/plastic into a continuously formed piece by forcing it through a die.
Fabric Design - the combination of number of fibers or yarns and size, in both warp and filling, and the manner in which they are processed. Fatigue strength - the maximum cyclic stress a material can withstand for a given number of cycles before failure occurs. FDA Approval - FDA-approved materials are used for indirect and direct contact with food products, except those that fall under USDA requirements, such as meat, fish, poultry and dairy products (which fall under 3A sanitary standards). Finger Splice - cut of the belt ends into mating fingers. Finish - a description of surface smoothness or variations from smoothness on the face of a roll by certain accepted classifications determined by each user industry. Fire Retardant - a conveyor belt is fire retardant when it is made in compliance with ISO 340. Flex Cracking - a surface cracking provoked by recurring flexing or bending. FPM - feet per minute (abbreviation). Friction - resistance to motion due to the contact of surfaces.
Gauge - the measure of thickness of the individual elements making up a rubber or plastic product. Grade of Belting - the belting cover quality based on gouge cut and abrasion resistance.
Heat Build-Up - a rise in temperature in rubber or plastic products resulting from hysteresis, converting mechanical energy into heat, caused by friction and deformation. Hysteresis - the measure of heat buildup caused by friction or other mechanical action when rubber or plastic is in motion.
Impact - a single stroke or contact of a moving object with another one (moving or steady). Impression - design formed during vulcanization in the surface of any rubber by a method of transfer, such as fabric impression or molded impression.
Joint - the section where belt ends are fastened by heat and pressure or mechanical means.
Lift - the net vertical distance items are raised to by a conveyor or bucket elevator. Load bearing - the amount of weight that can be placed onto the face of a roller or pulley before the material (coating in this case) starts to lose its physical integrity and begin to deform. It is usually expressed in pounds per inch or pounds per unit volume.
Maximum service temperature - maximum continuous operating temperature ignoring a temperature increase caused by hysteresis. Memory - materials ability to revert in dimension to a size previously existing at some stage of manufacturing. Minimum Pulley Diameter - the smallest pulley diameter around which a belt can drive. Millable - the milling of uncured rubber in the production or processing stage before curing of the rubber compound. Generally these processing steps are required to allow for specific molding, extrusion and curing processes. MSHA - Mine Safety & Health Administration (abbreviation). MSHA flame retardant test: Flame test procedure for underground conveyor belting, pulley lagging prescribed by the MSHA of the US Department of Labor.
Oil Resistance - an ability to withstand the deteriorating effect of oil (petroleum) on the physical properties. Operating Tensions - the tension of the longitudinal section of a belt system (tight side and slack side) when conveying items, as distinguished from tension when the belt is running empty. Ozone Resistance - an ability to withstand the deteriorating effect of ozone (usually cracking).
Perforated Belts - the belts with holes punched through the material for dewatering or vacuum purposes. Permanent Stretch - elongation permanently removed from a belt when it is used for the first time. Plasticity - the ability of a material to withstand continuous and permanent deformation by stresses exceeding the yield value of the material without rupture. Polyurethane - strong, extremely abrasion, cut and impact resistant material. Can be made into films, solid molding, or flexible foams. UV exposure can produce brittleness, reduction in properties and yellowing. Can be made in thermoplastic or thermoset formulations. Profile Top Cover - a surface with a series of continuous or interrupted, straight or curved ridges, across the belt at equal intervals to enhance the belt’s ability to move materials up or down.
Rating - recommended normal working tension (for a belt). Release - material incorporated into a compound to help prevent sticking to each other or to other materials. (IE: Teflon, silicone, synthetic waxes and blends of these materials are common release agents). Resilience - capability of returning to original size and shape after deformation. Resistance to denting - materials ability to resist denting due to impact by an object with mass. Reversion - 1) the change in vulcanized rubber – the result of aging or overcuring in the presence of air or oxygen usually resulting in a semi-plastic mass. 2) the basis of rubber reclaiming processes which is aided by the use of swelling solvents, chemical plasticizer and mechanical disintegration to obtain a workable mass. RMA - the Rubber Manufacturers Association, Inc. (abbreviation). Rough Top - a belt made with projections in the carrying surface to improve the ability of the belt to carry material on inclines. Rubber - an elastomer, generally implying natural rubber, but used loosely to mean any elastomer, vulcanized or unvulcanized.
Safety Factor - the ratio of breaking strength to rated working tension. Selvage - selvedge - the lengthwise woven fabric edge. Shelf Storage Life - a period of time during which a product retains its intended performance capabilities prior to use. Shore “A” - a scale used to quantify hardness of rubber-like compounds. Typically the durometer is checked after curing. Shore “D” - scales used to quantify hardness of harder urethane or plastic-like compounds. Typically checked after curing. Slab Belting - belting made in a longer and wider width for later cutting into shorter lengths and widths. Slider Bed Conveyor - a conveyor with a belt riding over a flat support surface (sections or full length), as opposed to being supported by a series of rollers. Slip - different movement between the pulley surface and the belt. Splice - a method of joining belt ends together without utilizing a mechanical fastener. Splice Angle - belting splice angle. Static-Conductive - the capability to conduct static electricity, i.e. static-conductive belt material will allow a static electrical charge to be conducted through the belt thickness. Swelling - an increase in volume.
Take-up Travel - the distance that a take-up is able to move during belt operation. Tape Line Measurement: Maximum Length - the inside circumference of a belt measured around the pulley surfaces when the take-up idlers are moved out to where they take up all the belt slack that their movement permits. Tape Line measurement: Minimum Length - the inside circumference of a belt measured around the pulley surfaces when the take-up idlers are moved in for the installation of the shortest belt possible. Taper - any linear change in diameter, with distance, between specified points. Taper-crown - a type of crown in which the diameter decreases linearly from the center to each end. Tear strength - maximum load required to tear apart a prescribed size rubber sample. Tensile strength - the amount of force required to stretch a prescribed sample size to the breaking point. Tension, Maximum - the highest tension occurring in any portion of a belt drive. In a two-pulley drive, it is the tight side tension. In conveyors, the maximum tension may occur at a point other than the drive pulley. Tension, Minimum - the lowest tension occurring in a belt / conveyor / or elevator system under operation conditions. Tension Rating - recommended maximum safe working tension. Tension, Working - the stress on a loaded belt in motion. Thermoplastic PVC/PU - material that will soften and flow when heat is applied. Thermoset PVC/PU - material that will not soften when heat is applied. Tolerance - (1) the upper and lower limits between which a dimension must be held; (2) the total range of variation, usually bilateral, permitted for a size, position, or other required quantity. Total indicated runout (TIR) - a measurement, usually expressed in thousandths of an inch, of the variation in position of the surface of the roll as it rotates around its axis. It is measured in one plane perpendicular to the roll axis. Transition Distance - the distance between the last fully troughed idler and the flat driving or discharge pulley. Troughability - the property of a belt that permits it to conform to the contour of troughing idlers.
Undercure - less than optimal state of vulcanization indicated by tackiness, lower than expected durometer or inferior physical properties.. USDA Approval - United States Department of Agriculture (USDA) government approval needed for chemicals or materials to be used in direct contact with fish, meat, poultry and dairy products.
Vulcanization - the process of permanently changing a rubber or urethane compound to a cured state with heat and pressure and the appropriate facilitating chemicals to initiate the chemical crosslinking process. Vulcanized Splice - belt joint created through vulcanization process. Vulcanized Splice Step Length - the longitudinal distance between steps in the splice.
Weft - crosswise, filling threads in fabric. Winged Pulley - a pulley with radial vanes extended from the supporting structure of the center shaft to minimize entrapment material that otherwise would build up and damage the belt.
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