Conveyor Belts

Steel Cord Belts

The current mining techniques demand that Conveyor Belts handle ever greater volumes, with increased centre distances and high lifts, all of which necessitated a stronger belting. Yet, the high strength of the Steel Cord tension carrier is not the only reason why Steel Cord belts are increasingly being used as an optimum and economic alternative to other bulk material handling alternatives.

Steel cord belt in use

Advantages

  • Belts reinforced with Steel Cords deliver extremely high strengths.

    When operating tensions in excess of 200 kN/m are required, belts reinforced with Steel Cord are the only alternative and today belts are being designed for ratings upto ST 10000. However, due to its numerous advantages, Steel Cord belts are increasingly used even in ratings as low as ST 630.

  • Steel Cord Conveyor Belts have a long life expectancy.

    Conveyor Belts with Steel Cord reinforcement members are virtually maintenance-free and can be supplied with increasingly thicker rubber covers for the same rating. The carcass, having a minimal risk of failure, yields very long life, sometimes even lasting for the entire duration of the project without affecting the overall design.

  • Large Centre Distances can be planned.

    Steel Cord Belts have very low elongation and resultantly systems with large centre distances can be planned, without having to account for limitations of take-ups and transfer points.

  • Low Pulley Diameters can be used.

    For the same rating, the thickness of the tension member in Steel Cord belts is considerably lower than that in a fabric reinforced belt (carcass thickness) and hence is able to operate with lower pulley diameters. The superior dynamic modulus of the Steel Cords over the fabric carcass also ensures that flex fatigue sets in very slowly making the selection of lower pulley diameters technically viable.

    Again the safety factor requirements for Steel Cord Belts are 6.67 against 9 – 10 for Textile Conveyor Belts, and therefore when compared with textile belts of equivalent rating the difference in pulley diameters becomes even more striking.

  • Low Elongation, high impact resistance.

    The elongation of Steel Cord Belt is a function of elastic modulus of the steel and the amount of twist in the cord. The very low elongation of Steel Cords makes short take-ups a fact. Typically elongation is down to 0.25% on total belt lengths.

    The geometry of a Steel Cord Belt provides for greater quantum of rubber per unit volume compared to fabric reinforced belts permitting a more effective absorption of impact energy.

    Consequently Steel Cord Belts allow discontinuous feed of heavy individual pieces without localized elongation.

  • Excellent Troughability.

    Even the strongest Steel Cord Belts trough perfectly on deep troughed idler sites. This ensures easy belt training and the realisation of superior volumetric capacity of the belt, whereby, the customer can either convey more material at the same speed or employ narrower Conveyor systems.

  • Long Splice Life and Strength.

    Properly provided Belt Splices can last as long as the Belt itself. They can also achieve spliced strength equivalent to almost 100% of the strength of the Belt.

  • Easily Reconditioned and Re-juvenated.

    Steel Cord Belts can be repaired with Hot or Cold vulcanization and the damaged edges can be restored to original width by hot repair. Worn out covers can be replaced with fresh rubber, durable enough to completely re-juvenate the belt, delivering yet greater economy for the customer.

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Belt Features

Conveyor Belt Cross–Section

A Typical Steel Cord Conveyor belt has three distinct components, and a fourth optional protective element. These are the steel cable, the bonder layer and the top & bottom covers. To prevent longitudinal rips an optional component such as sensor loop or breaker may be incorporated.

Steel Cord

The 'building block' for the reinforcing Steel Cords are round steel wires. Such Zinc-coated high-carbon wires are laid helically with a uniform twist around a central core to form the 'Strand'. Strands so formed are, in turn, helically laid around a central strand to form the reinforcement 'Cord' of the Steel Cord belt. Forech sources Steel Cords only from globally established manufacturers and conduct periodic checks on the cords supplied to evaluate the Component Dimensions, Tensile Strength, Elongation (Static & Dynamic), Openness, Effectiveness of Zinc coating, Cord Pullout etc. Cord types 7x7 and 7x19 are most popular and can cover a large range of Steel Cord Belt ratings.

Bonder Rubber

The function of the bonder rubber is to maintain a bond between the metallic cords and the rubber polymer in the Steel Cord Belt. The bonder rubber not only has to create the metal-rubber bond but – for optimal product performance – is also required to be viscous enough to flow into the air gaps/voids between individual filaments in each cord to offer additional protection against environmental threats as well as to protect adjacent filaments from chafing against each other.

Cover Qualities

Forech manufactures its entire range of Steel Cord Belts (in widths upto 2400mm and in ratings upto ST 10000) in General purpose or Fire Resistant grades (refer to chart below). For extreme applications, Heat Resistant and Oil Resistant Belts can be supplied.

All General Purpose Grade Belts and Fire Resistant Belts can also be supplied with a low rolling resistance compound for the back cover to optimize power consumption. For detailed technical specifications please refer to Forech.

Cover Grade Standards (Whenever Applicable) Applications
X, Y
M		 DIN – 22131
ISO-EN –15236
AS – 1333
SABS – 1336		 X and M - are for toughest applications where very large abrasive lumps are handled.
Y are General purpose for handling of abrasive materials.
Fire Resistant DIN – 22131
ISO EN – 1340
FRAS S – 1334
SABS – 1336
MSHA
CAN-CSA-C–M422-M87		 Excellent self extinguishing properties, mainly used for overland or underground coal and gold mining.
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Standard Steel Cord Range

ST Rating Recomm-ended Cord Dia (mm) Pitch (mm) ±1.5 Belt Width Minimum Recommended Pulley Diameters (mm) for MAWT utilisation > 60%
600 650 750 800 900 1000 1050 1200 1400 1500 1600 1800 2000 2200 2400 A B C
500 2.6 13.8 42 45 52 56 63 70 74 84 99 106 113 128 142 156 169 400 315 250
560 2.8 13.8 42 45 52 56 63 70 74 84 99 106 113 128 142 156 169 500 400 300
630 3.0 13.8 42 45 52 56 63 70 74 84 99 106 113 128 142 156 169 500 400 300
710 3.1 13.8 42 45 52 56 63 70 74 84 99 106 113 128 142 156 169 500 400 300
800 3.3 13.8 42 45 52 56 63 70 74 84 99 106 113 128 142 156 169 500 400 300
900 3.8 15.3 37 40 47 50 56 63 66 76 89 96 102 115 128 141 151 630 500 400
1000 4.0 15.3 37 40 47 50 56 63 66 76 89 96 102 115 128 141 151 630 500 400
1120 4.3 15.3 37 40 47 50 56 63 66 76 89 96 102 115 128 141 151 630 500 400
1250 4.5 15.3 37 40 47 50 56 63 66 76 89 96 102 115 128 141 151 800 630 500
1400 4.8 15.3 37 40 47 50 56 63 66 76 89 96 102 115 128 141 151 800 630 500
1600 5.5 17.3 33 36 42 45 50 56 59 67 79 85 90 102 113 124 135 800 630 500
1800 5.9 17.3 33 36 42 45 50 56 59 67 79 85 90 102 113 124 135 1000 800 630
2000 6.4 17.3 33 36 42 45 50 56 59 67 79 85 90 102 113 124 135 1000 800 630
2250 6.8 17.3 33 36 42 45 50 56 59 67 79 85 90 102 113 124 135 1000 800 630
2500 7.4 19.4 30 32 37 40 45 50 52 60 70 75 81 91 101 111 119 1250 1000 800
2800 8.0 19.4 30 32 37 40 45 50 52 60 70 75 81 91 101 111 119 1250 1000 800
3150 8.6 19.4 30 32 37 40 45 50 52 60 70 75 81 91 101 111 119 1250 1000 800
3550 9.2 19.4 30 32 37 40 45 50 52 60 70 75 81 91 101 111 119 1400 1250 1000
4000 9.8 19.4 30 32 37 40 45 50 52 60 70 75 81 91 101 111 119 1600 1400 1250
4500 10.4 19.4 30 32 37 40 45 50 52 60 70 75 81 91 101 111 119 1600 1400 1250
5000 11.0 19.4 45 50 52 60 70 75 81 91 101 111 119 1600 1400 1250
5600 11.8 19.4 45 50 52 60 70 75 81 91 101 111 119 1800 1600 1400
6300 12.8 20 43 48 50 58 68 73 78 88 98 108 116 2000 1800 1600