Polymerization processes in a bulk loop reactor are described herein. The at least one channel includes inputoutput data lines and control signal lines, which are connected with the plurality of memory devices, and chip enable signal lines respectively connected to each of the plurality of memory devices, wherein the chip enable signal lines enable the plurality of memory devices independently. On the other hand, on the inside of the closed-loop first tightening portions, the space between a first line and a second line gradually becomes wider toward the greater trochanter position, whereby a side hole is formed.