Why Does The Skirting Seal Wear Out Instead of The Belt?

I have been asked, multiple times, how you can get away with a seal of higher durometer than the belt. The answer to this is related to the fact that the durometer is not the only property influencing wear in the conveyor belt. Modulus of elasticity has a much larger impact than the durometer.

Durometer is a measure of the surface hardness of a material.  Modulus of elasticity is the measure of how much the material deflects under load, or the bulk material elasticity. 

To put it simply, in three body wear, or a situation where a particle is abrading on two surfaces, the wear will be influenced more by modulus than durometer. A particle will become trapped between the seal and the belt. It pushes against the seal and the belt. If the belt is stiffer than the seal, the particle will deform the seal.

If the seal is stiffer, the particle will deform the belt.

Mechanical abrasion takes place in the body that is deformed the most. ApronSeal^TM Skirting, though it usually has a higher durometer than the belt, tends to have a lower modulus than the belt. This is the main reason why you can get away with a seal of higher durometer than the belt.