The trend is indeed towards all polyester but it is largely driven by cost with the negative consequence mitigated by technology advances.

Twenty years ago nylon x nylon ply construction was the mainstay in multi-ply fabric reinforcement of belts. This was a very good belt with very good strength, troughability and impact resistance. The companies that excelled in manufacture of this belting retained the elastic stretch but minimized the permanent elongation. Goodyear was and remains the best at controlling the permanent stretch. Lower cost was the driver for moving towards polyester warp fabric. Lower stretch, elastic and permanent was cited as an advantage. I question the advantage of the lower elastic stretch as it negatively affects impact resistance (work = force x distance) transition length and pulley diameters. Also driven by cost recommended safety factors against breaking were also reduced for belts reinforced with multi-ply fabric with polyester warp. Some earlier belts were of polyester warp and weft fabric but these proved problematic, failing to trough properly because of the higher transverse flex stiffness. Fast forward to the present and the troughabilty problem appears to have been solved as the major manufactures are now offering polyester x polyester fabric multi-ply reinforced belting.

Nevertheless much of Asia still offers the nylon x nylon fabric reinforced belt woven and treated to mitigate stretch both elastic and permanent. Nylon x nylon fabric remains the preferred for heavy feeder application because of the superior impact and abuse resistance.

The nylon x nylon fabric multi-ply belting which was dominant 20 years ago remains on the market today for the Dos Santos Sandwich Belt High angle Conveyors. The troughed belt line of these high angle conveyors travels along alternating convex curves. It is thus subject to the radius of curvature constraints, which ensure that the belt is neither over-stressed at the edges nor relaxed at the middle, and repeaded transitions from one troughed curved belt line to an opposite curved belt line. Nothing performs better than nylon warp in this regard. Control and knowledge of the elastic modulus are essential in the Dos Santos Sandwich Belt applications. The reward is priceless; a high angle conveyor system that use all conventional conveyor equipment and smooth surfaced rubber belt that can be continuously scraped clean and has virtually no capacity limitations.

Joe Dos Santos ■

Nylon conveyor belt is cotton canvas belt replacement products, high strength, fatigue performance good advantage, but in the use process nylon conveyor belt use elongation is bigger, easy extension, Polyester conveyor belt is nylon conveyor belt upgrade products, it has the advantages of the nylon conveyor belt, at the same time because in use process elongation are small, so the suitable range more widely. But polyester canvas and rubber adhesive performance than nylon canvas, so cementing safety polyester conveyor belt as nylon conveyor belt.

So the cotton conveyor belt produce less,other will more. Which conveyor belts need to use depends on the deliver condition and material.

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