输送带在使用一段时间后会变长
The conveyor belt will be longer after a period of use
输送带在使用过程中会伸长，其中一部分是弹性伸长，在外力撤销后能恢复原状，另一部分是骨架材料的编制收缩的伸长量，这一部分是无法恢复的。常用织物芯输送带中，EP输送带的伸长比较小，而NN输送带伸长比较大，而且在使用过程中，NN输送带由于锦纶纤维受力后的蠕变比较大，因此在使用过程中，伸长比加大，而且因为纤维的蠕变，因此在外力撤销后，能收缩回去的量就比伸长小的多了。
The conveyor belt will stretch in the use process, one part of which is elastic elongation, and it can be restored to the original state after the external force is withdrawn, the other part is the elongation of the skeleton material's weaving shrinkage, which is unable to be restored. In the commonly used fabric core conveyor belt, the elongation of EP conveyor belt is relatively small, while that of NN conveyor belt is relatively large. In the use process, the elongation ratio of NN conveyor belt is increased because of the creep of nylon fiber after stress. Moreover, because of the creep of fiber, the amount of shrinkage can be much smaller than the elongation after the external force is withdrawn.