CONVEYOR BELT TESTING

Fire safety tests please see here - and for splice testing there

ABRASION

The abrasion resistance is measured by moving a test piece across the surface of an abrasive sheet mounted to a revolving drum. It is expressed as volume loss in cubic millimeters, for instance 150 mm³.

A smaller number indicates better abrasion resistance.

ELONGATION

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. 2 - 10 %, because this is a typical operating range for textile conveyor belts. After 200 cycles, the amount of permanent elongation of the test piece and the amount of elastic elongation produced by the force differential are recorded from a force-elongation.

Typical permanent elongation values: Polyamide (P): 1,0-2,5%, Polyester (E): 0,5-1,5%, Aramide (D): 0,25-0,75%, Steel: 0,1-0,25%.

Other (static) tests, e.g. as per DIN 22102, require a reference tension of 10% of the nominal belt breaking strength. The maximum total elongation for EP belts is 1,5, 2,5 or 3,0 %, depending on belt class

Hysteresis curve

RHEOMETER

A rheometer test identifies most of the problems in a rubber compound.

Test procedure:

An uncured sample is placed between two dies. The lower die oscillates. The upper die is connected to a sensor to measure the torque response of the rubber at the deformation during the vulcanization process at a constant temperature.

Rheometer curve

STEEL-CORD PULLOUT STRENGTH

Steel-cord pull-out strength,

static (just pull) or dynamic (10.000 cycles),

without reheating or with reheating (to simulate splicing).

The cyclic load ranges from 3.6 percent to 36 percent of the nominal static pull-out strength for a given cord diameter (see DIN 22131 or AS 1333).

The test is carried out until the number of required cycles is achieved or till failure of the bond occurs.

Steel cord pull-out strength

Free troughability test

TROUGHABILITY

Supported troughability test

Supported troughability test
Hanging troughability test

STEEL CORD TENSILE/BREAKING STRENGTH

The actual steel cord breaking strength is ascertained by tearing the entire rope until it breaks. Result stated in kN.

Steel cord breaking strength test
Steel cord breaking strength test

RUBBER STRENGTH AND ELONGATION

DENSITY

TEAR RESISTANCE

The tear resistance is the quotient of the force required for a test piece of specified shape and size with a defined cut to resist tear propagation.

The force is acting in the direction perpendicular to the plane of the cut and of the test piece thickness.

Tear resistance test

SEPARATION STRENGTH / ADHESION

Test as per ISO 252.

Normal minimum requirements are 6 N/mm between plies and 4,5 N/mm between cover and ply.

HARDNESS

It is not common to determine a hardness requirement.

Usually a belt cover will have a hardness between 55 to 70 °ShA.

Hardness gauge

 

IMPACT RESISTANCE

A test mainly for steel cord conveyor belts with different combinations of additional reinforcements ("breakers").

There are a few different methods on the market, but no standard yet.

Impact tester