The chain on a conveyor experiences a variety of changes as a direct result of the sprocket’s deterioration. One visual giveaway to a chain’s wear is to look at the sprocket. If the gaps between the sprocket teeth look uneven and take on a hooked shape, then it’s time to replace both sprocket and the chain.
The Cause
If the wear on each tooth is not even, the result will be an inconsistent pitch as the teeth deteriorate. This indicates that when the chain interacts with the sprocket, it may only engage with half of the teeth of the sprocket. For example, if the sprocket has eight teeth, the chain may only engage with four of those teeth. Because of this, there will be a difference in the strains placed on each pitch as the chain is driven by the sprocket.
This, too, will be different on each pitch due to the fact that the chain is fed over its whole length. Also, as the chain engages with the sprocket, the sprocket will contact a larger area, which will result in increased wear on the bush, and if there is a roller on the chain, this could cause issues when the chain is disengaging from the sprocket. If the sprockets are driving a twin chain, then you will have an uneven distribution of weights unless the wear on both chains is precisely the same.
This might result in anything from increased wear, which would shorten the chain’s life, to overloading, which would lead to the chain breaking.
The teeth on the sprocket in the picture weren’t hardened, thus they caused damage to the chain, which was a twin chain with uneven wear that shortened the chain’s lifespan. The sprocket was installed on an infeed conveyor at a biomass factory.
The Remedy
It was replaced with a hardened tooth sprocket, which wears considerably more slowly and more consistently than the previous one. As a result, the life of the chain was extended, which ultimately resulted in an improvement in the performance of the conveyor.
Less downtime means that it is much simpler to figure out when to schedule a change due to continuous even wear; in this case, that would be during a planned outage.
