Conveyor Belt Glossary


Wearing away by rubbing, scraping. The established abrasion tests, for instance as per ISO 4649, have practical relevance only for grinding kind of applications. The abrasion value alone is no indicator of a belt's wear resistance.



The bonding strength between two materials.



The red glow persisting after extinction of the flame, for instance in certain fire resistance tests.



The exposure to an environment for a period of time.



A compound ingredient used to retard deterioration caused by oxygen.



Code letter E as per DIN 22102 and 22131. Grades K, S and V have a surface resistivity of min. 300 MOhm. Tested as per DIN 22104.



Stands for aromatic polyamide. Its acronym is D. Aramide is a low elongation, light, high-strength fiber with limited applicability for conveyor belts because of its poor fatigue properties and sensitivity to chafing. Expensive. Loses strength under UV radiation (splicing!). Trademarks are Kevlar and Twaron.


Arc of contact

The circumferential portion of a pulley which is engaged by a belt.



Association for Rubber Products Manufacturers, a successor of RMA. Published their conveyor belt handbook in 2011, determining grade 1 with tensile strength of 17 MPa, elongation at break of 400 % and volume loss of 125 mm³.

Belt clamp

Beams or metal plates secured transversely to hold the belt in a desired position.


Belt cleaning device

A scraper or rotating device pressed against the belt surface to remove material stuck to the belt.


Belt fastener

A device for holding two ends of a conveyor belt together. More.


Belt grade

A classification of the rubber quality and properties as per ISO, DIN or other standards. More...


Belt marking

Usually, every belt length has an embossed individual serial number, plus the belt type and the manufacturer's acronym. The size and positioning of the marking can be agreed between customer and manufacturer. Example


Belt modulus

The force per unit width of belt required to produce a stated percentage of elongation, or the ratio of stress to strain. See "Modulus of elasticity".


Belt sag

The amount of vertical deflection of a conveyor belt from a straight line between idlers, usually expressed as a percentage of the center to center spacing of the idlers.


Belt slip

The speed differential between the belt and the pulley surface, accelerating the abrasion of the belt cover.


Belt tear resistance

Or "tear propagation resistance". A belt sample is cut and then further separated. Odditiy: as per ISO 505, the parties must decide with order placement, whether the minimum value required is related to a test with or without belt covers.


Belt tension

See "tension".


Belt training idler

An idler having a belt-actuated swivel mechanism to automatically control side drifting of a conveyor belt.


Belt turnover

A system of idlers to turn a belt over (upside down).


Belt weight

See Chart.


Belt width

Wherever possible, standard widths (for instance 1000, 1200, 1400 mm etc.) should be chosen, so they fit to other standardized conveyor components.


Bending modulus

The force required to induce bending around a specified radius and, hence, a measure of stiffness.


Bend pulley

A pulley used to change the direction of a belt.


Bias cut

A cut of belt ends made diagonally at an angle less than 90 degrees - usually 30° - to the longitudinal axis. Video.


Binder warp yarn

One of the warp systems in a straight warp fabric interlaced with the filling yarn to provide the strength to hold mechanical fasteners.



Migration to the surface of plasticizer, waxes or similar materials to form a film or beads.



A raised spot on the surface or a separation between layers usually forming a void or air-filled space in the vulcanized conveyor belt.


Booster drive

Used in some long conveyors to reduce the power/tension at the drive pulley.


Bottom cover

The non-carrying belt side towards the pulleys. Usually thinner than the top cover.



A bow is a longitudinal curve in a belt on its concave side. A bow can be created during manufacture, improper storing, splicing or tensioning. See also Camber.



An extra ply made of fabric or steel for shock absorption to minimize gouging.


Breaking strength

The breaking strength of the conveyor belt, either nominal/minimum (e.g. St 2000) or ultimate/actual (e.g. 2197 N/mm). Test


Bucket elevator belt

A transversely rigid belt with buckets attached, for vertical conveying.


Bulk density

Required for determining the troughing angle, the angle of repose and maximum inclination. Table.


Butt gap

The distance between two opposing steel cords in a conveyor belt splice.



A roller mill equipped with three or more internally heated or cooled drums, used to continuously sheet out polymeric compound to wipe it into the interstices of a fabric leaving a small portion of it on the surface of the fabric, or to lay a continuous sheet of compound on a fabric. More...



Describes a crooked conveyor belt ("banana").



The material load on the belt, given in tons per hour (t/h). 


Carbon black
Carbon black is used to increase strength and abrasion resistance of a rubber compound. Smaller particles provide better reinforcement but are more difficult to process. The Chinese used carbon black 500 years ago to make ink and lacquer.



The fabric plies or steel cords (plus breakers) of a belt, as distinguished from the rubber covers. The carcass provides the tensile strength to move the loaded belt. 


Carry cover

The material carrying side of a conveyor belt. In most cases thicker than the bottom cover.


Catenary idlers

A type of flexible belt-carrying idlers with ends supported in pivoted stands.


The most advanced conveyor belt monitoring system, based on radiographic technology. Supplies and processes nonstop live information about any deficiencies of a conveyor belt.



The distance between the center of two pulleys. Sometimes also called "centers" or "center distance" or "conveyor length".


Ceramic pulley lagging

Used for high-capacity conveyors or in slippery environments. Offers higher wear resistance and a higher friction factor.


Chute lining

Highly abrasion resistant elastomeric lining in a chute to protect the metal chute from abrasion wear.


Clamping force

Depending on the friction factor of clamp and belt surfaces and on the (downhill) force. Chart.



A device for removing adherent material from the belt. More commonly used term: Scraper.



Transverse raised sections on a conveyor belt to stabilize material carried up an incline.


Closed belt

See Pipe conveyor belt.



A wrong term for pipe conveyor belt.


Coefficient C

The length coefficient used for calculating the secondary resistances. Chart.


Coefficient f

See f value.


Cold resistance

Usually, conveyor belts are resistant to up to -30°C. Lower temperatures may be achieved with special compounds. Constant movement of the belt may be required.


Concave curve

The concave radius of a conveyor must be sufficiently large to avoid belt lifting from the conveyor.


Compression set

The deformation in a material remaining after it has been subjected to and released from a compressive force.



Several strands of yarn twisted together


Cord fabric

A fabric with plied or cabled yarns in the warp direction and a light weight filling yarn spaced only sufficiently to process the fabric.


Cord stripper

A tool for easy separation of steel cords from the belt as part of the splicing procedure. Requires a winch. More...


Core rubber

Also called "insulation gum". The rubber used for filling the gaps in a steel cord and improving adhesion between the cord and the top and bottom covers.


Counter weight

The weight applied to the take-up assembly to maintain proper belt tension. Take-up length.



The outer rubber (or PVC) component of a belt. Protecting the belt carcass and providing drive friction. There are cover grades for a broad variety of applications. A cover usually consists of a principal polymer and assorted modifiers, carbon black, antioxidants, accelerators, fillers, plasticizers etc. Compounding.


Cover grade

Please follow this link for physical data of the most common cover grades.



Polychloroprene rubber. Primarily used for covers for underground coal mining. Comparison. Safety.



A sharp break or fissure in the surface.



The action of a belt alternately losing speed on the driving pulley and gaining speed on the driven pulley.



The waviness of the yarn in a woven fabric or the difference in distance between two points on a yarn as it lies in a fabric, and the same two points when the yarn has been removed and straightened. Expressed as a percentage of the distance between the two points as the yarn lies in the fabric.


Crowned pulley

A pulley with a greater diameter at the center than at the edges.



A belt tending to form a cup by raising the edges. Depending on severity, it may not be able to be guided by the idlers or even be loaded properly.


Cut edge

The uncovered edge of a belt, created by cutting after vulcanization. The carcass is visible from the sides.

Deep trough

A term used for a troughing angle of 45, rather 60°.



A deleterious change in the chemical structure of a material.



The separation of layers of material, for instance textile ply from top cover.



A yarn sizing system for continuous filament synthetic fibers on the basis of the weight in grams of 9000 meters of the yarn.



The ratio of the mass of a body to its volume or the mass per unit volume of the substance. For ordinary practical purposes, density and specific gravity may be regarded as equivalent.



For Deutsches Institut für Normung, German Institute for Standardization. World's first standards for conveyor belts were published by DIN in Germany.


Dipped fabric

A fabric coated with rubber compound by passing through a rubber solution and drying.


Drop energy

The energy caused by the drop of the conveyed material onto the conveyor belt. Depending on lump size, drop height etc. See also Impact resistance.


Dynamic splice strength

The test and evaluation method is described here. Usual dynamic splice strengths are given in table 10 of DIN 22101. More...

E' and E''
E' is the dynamic modulus of the rubber which is in phase with the applied strain loading. E'' is the loss modulus, which is out of phase with the applied strain. The ratio of E''/E' = tan delta, which is the internal friction of the rubber. E' is an important factor for low indentation rubber.



Tendency to return to the original shape after deformation.



A viscoelastic, amorphous  polymer with low Young's modulus and high failure strain. Sometimes called rubber. Properties. Production.


Electrical conductivity

A measure of how well a material accommodates the transport of electric charge, measured in Ohm (Ω). Photo.


Elevator belt

Used for vertical conveying, with buckets mounted to it.



The total belt elongation consists of an elastic (which recovers) and a plastic (which remains) portion. As per ISO 9856 a belt sample is subjected to a sinusoidal cyclic stress that varies from 2 to 10 % of the belt's nominal breaking strength. Test


Elongation at break

The percentage the rubber or belt can be stretched until it breaks.


Endless length

The length of a closed belt (without splice allowances).



A process whereby rubber is forced through a shaping orifice. More...


Eytelwein's equation

Determines the optimum difference between the forces F1 and F2 without belt slip. Equation.

Fabric belts

See textile conveyor belts.



See "mechanical fastener".



The weakening of a material occurring when repeated application of stress causes permanent strain.


Feeder belt

A belt that discharges material onto another conveyor belt. Often used for belts extracting bulk materials from under a dump hopper or regulating feed to a crusher or screen.



A continuous fiber of discretionary length.


Fire or flame resistance

Retards the burning action of fire or flame. Achieved by adding fire retardants to the compound or by using fire resistant elastomers or plastomers. More...


Flat-to-trough transition zones

The transition length between pulley and deepest trough station. This length must be sufficiently high to prevent major additional tensions in the conveyor belt edges. Influencing the required conveyor belt breaking strength.


Fleximat belts

A trademark for "woven" steel cord conveyor belts. Belt manufacturers tend to use "Flex" in their own belt names. More.



The resistance to tangential motion between two surfaces. For rubber, the classical laws of friction are not applicable, since rubber has no rigid surface. The individual friction factor must be determined experimentally. In general, higher hardness and abrasion resistance result in lower friction. Chart.


f value

The coefficient f (also called artificial or fictive friction or resistance coefficient) is resulting from the correlation between the weights and the motional resistances of the belt conveyor. A typical f value would be 0,016.

In optimum installations with low rolling resistance belts, even f values of around 0.010 have been found. Chart.

In contrary to DIN and ISO, CEMA works with Kx, Ky and 0.015 instead of f, which f is a sum effect of.


The effect of sharp heavy material falling onto a conveyor belt cover to loosen or tear out pieces of the cover. Photo



There is a wide choice of conveyor belts for all gradients. From normal troughed conveyor belts, via pipe conveyor belts through to vertical elevator belts. Table.


Gravity take-up

A mechanical system that adjusts for the stretch or shrinking of a conveyor belt automatically by a weighted pulley in the system.


Grizzly bars

The bars at the loading point  absorb the impact energy from the lumps and redirect the (big) lumps to the belt; fines fall on the belt before the lumps.


Grooved lagging

Lagging with round or angular grooves to minimize material buildup on the pulley.



Degree of resistance to indentation. Determined in ° Shore A. More...  Photo.


Head pulley

The pulley at the discharge end of the conveyor.


Heat resistance

Normal belts usually are resistant up to 80°C. Special compounds can increase the temperature resistance to around 200°C.


Hooke's Law

Hooke's law of elasticity states that if a force (F) is applied to an elastic spring, its extension is linearly proportional to its tensile stress σ and modulus of elasticity (E): ΔL = 1/E × F × L/A = 1/E × L × σ


Horizontal curve

The radius of a horizontal curve is required for the layout of the diameter of a pipe conveyor belt. More...


Hose belt

See Pipe conveyor belt.


Hysteresis loss

A loss of mechanical energy due to successive deformation and relaxation, measured by the area between the deformation and relaxation stress-strain curves. See also "Elongation".


A non-powered roller supporting the belt.



Industrial Internet of Things. Electronic interaction between different components of a belt conveyor. The belt can be integrated digitally by the output of X-ray monitoring systems.



A stroke of a body dropping on the belt.


Impact idler

A belt idler having a resilient roll covering, resilient molded elastomer rings, springs or other means of absorbing impact energy at the place where material falls onto the belt.


Impact resistance

The relative ability of a conveyor belt assembly to absorb impact loading without damage to the belt. See also "transverse reinforcement". Test.



The gradient of a conveyor. The maximum (uphill) inclination for non-profiled belts is around 18° for ore. In general, the angle of repose of the conveyed material must be larger than the inclination angle of the conveyor. Chart.



Since the conveyor belt is permanently subjected to many strains and stresses, frequent, regular inspection of it is important. More...


Indentation rolling resistance

The energy consumed by internal friction caused by deformation when the belt moves over idlers. More...



The connection of two belt ends. More common term: splice. More...



A trademark for para-aramide (aromatic polyamide). See Aramid.



A temporary or permanent distortion of belting caused by doubling the belt on itself.


A smooth or embossed covering on a pulley to increase friction between belt and pulley.


Leno weave

An open mesh fabric in which the warp yarns are held by the filling yarns, with the filling yarns twisted around alternating warp yarns in opposite direction. Sometimes used as impact breaker.


Load support

Defining the belt's sag on the idler gaps. The sag may be an issue for very thin belts and wide gaps. Term widely used in North America.



Low rolling resistance. More...


Lump size

Conveyor belts are highly strained at the material feeding points. The intensity of the impact energy depends on the lumps' size, weight and shape.


Proper maintenance is very important to get the most out of your belt. Longer belts should be monitored by state-of-the-art systems based on X-ray technology. More...


Maximum tension

The highest tension occurring in any portion of the belt under operating conditions.


Mechanical fastener

Any mechanical device used to join the ends of belting. Sometimes also used for temporary emergency repairs. Illustration.


Modulus of elasticity

The force divided by the percent elongation to cause the elongation, related to the belt width. The lower the stretch, the higher the MoE. The MoE, sometimes called belt modulus, is influenced by the textiles (for instance the crimp of the yarn) or steel cords used and the way of belt manufacture, for instance the tension during vulcanisation. Example: The MoE for a 800/St2500 belt is 200 kN/mm. To stretch 1 m of this belt (elongation 0,15 %) by 1,5 mm, a tension of 240 kN is required. This is approximately 12 % of the nominal belt breaking strength.
The belt manufacturer should be consulted for exact figures. Equation.



Essential part of a Preventive Maintenance programme and IIoT. Extends belt life, reduces costs, increases safety. More...


Motion resistance

The resistances - "main, additional, inclination, special" - when moving a belt on a conveyor system. Illustration.


Moulded edge

A solid rubber belt edge f