Loop pit speed up the line. In a production line, if speed of the previous machine processing is slower than next one, there can be a looping between them. The material can be stored to reach max level of the machine capacity.It appears in slitting line(https://youtu.be/qKftKooHrEw ),roll forming machine,HF tube mill(https://youtu.be/y3XPj5kmTwI ) and so on.