• Excellent cut and tear resistance
• Low elongation
• High tensile strength
• Good impact resistance
• Excellent longitudinal flexibility
• Very good Troughability

The main functions of rubber covers are the protection of the carcass against wear or damages during the running of the belt and the conveying of the material.

The cover thickness required for a specific belt is in function of the material conveyed and of the handling method used. Thicker covers are required if the following conditions become more severe:

• Material abrasiveness

• Lump size

• Material sharpness

• Height of drop into the belt

• Loading angle

• Belt speed and frequency of load

Here the suggested curves to estimate the correct cover thickness. Usually the bottom cover is half the top.

ABRASION SERVICE

CL

Belts produced with this cover are recommended for all above ground applications where the resistance to abrasion is required. It is designed for the handling of heavy and abrasive materials such as gravel, crushed stones, sand, coal, cement, limestone, phosphate, salt, potash, etc.

Grade L ISO 10247 – Grade Y DIN 22102 - RMA 2

EC

Belts produced with this particular compound are of superior quality expecially for abrasion. The characteristics of resistance against cut, tear, abrasion, ozone cracking, together with long duration, improve the quality of this cover.

Grade D ISO 10247 – Grade W DIN 22102 - RMA 1

HEAT RESISTANT

CX

This cover assures a medium degree of abrasion resistance and is formulated for continuous service of hot materials at temperature of 130 °C (270 °F) with peaks of up to 150 °C (300 °F). It is recommended for hot materials such as clinker, coke, hot scraps, fly ash, etc.

SELFEXTINGUISH

BS

This cover is designed to serve applications where safety is important and the fire risk is high. It is recommended for coal, potash, sulphure.

According to ISO 340, ISO 284, DIN 22103, DIN 22104.

ELONGATION & CREEP

These mechanical properties refer to the elastic characteristics of cords and to our method of production defined to obtain the best performances of the final product.

Low elongation is one of the most important points of SIDERFLEX belts: laboratory tests made on rubbercoated cords give value of elongation as shown in the following table:

Creep is the permanent elongation that the belt shows in the first period of life. The great advantage of SIDERFLEX in comparison with textile belts is a very reduced creep, generally negligible. This property helps maintenance because the belt can be vulcanized just one time on original installation without need of new joint after a certain period of time.

CUT & TEAR RESISTANCE

Longitudinal cuts and tears are always a cause of belt replacements both in textile and conventional steel cord belts. SIDERFLEX, with its steel weft, is more resistant against this kind of damages.

Indicative values of cut resistance in kN for SIDERFLEX IW belts compared with multiply textile belts are shown in the following table:

IMPACT RESISTANCE

SIDERFLEX has high impact resistance. The effect of oversized material falling on to the belt at the loading point is absorbed by the flexible steel carcass and the high quality level of rubber used.

CORROSION PREVENTION

Various properties of our SIDERFLEX assure a superior

resistant against corrosion of steel cord:

The adhesion between steel cord and core rubber is obtained through a chemical reaction during the curing process between special chemical compounds present in the rubber and brass (Cu/Zn alloy) covering the cords. In comparison with other coating method (tipically Zn), brass assures an higher and more constant adhesion to rubber.

The open cord construction for IW, HE and ST carcass and the special design of regular cord used for ID carcass allow the penetration of rubber up to the center of the cords, virtually eliminating the capillary action of moisture.



During the vulcanizing process, the combined effect of heat and pressure produces the flowing of rubber into the cord center and the top and bottom cover become “one” with the steel carcass locked in the center. In conclusion, no ply eparation is allowed.

LONGITUDINAL FLEXIBILITY

The presence of a single ply and the special warp cords construction give to the SIDERFLEX IW & HE belts a considerable longitudinal flexibility.

At the same condition of fatigue stress this properties allows to use smaller pulleys than equivalent textile multy-ply.

It means that in existing plants it is generally possible to replace the original textile belts with SIDERFLEX IW & HE without any plant modification.

TROUGHABILITY

For a long time the majority of trough idlers have been produced with angle of around 20°. Due to the increasing demand for higher handling capacity, the angle of the idlers went up in value reaching 30-35° end even more.

SIDERFLEX belts, in all series and style, thanks to their transversal flexibility will trough perfectly up to 60° without any problem.

Here below, the table shows for each width of SIDERFLEX IW the corresponding maximum inclination angle according to ISO 703 and our practical experience.

For widths over 1200 mm, the test has not practical meaning.