Patent ID: 8034297

Claim:
A transfer system between a first and second reactor in a double loop reactor comprising: a first loop reactor; a second loop reactor; a by-pass line on the second loop reactor comprising a length of least 1.5 times a distance between the first loop reactor and the second loop reactor adapted to extend a proximity of the first loop reactor; two or more transfer lines arranged to transfer polymer product from the first loop reactor into the by-pass line at a point near the first loop reactor; and a regulation mechanism arranged to ensure equivalent flushing in each transfer line, wherein the regulation system comprises: a main flushing line adapted to carry isobutene and connect all transfer lines, wherein the main flushing line is equipped with a rotameter; secondary flushing lines, each connecting the main flushing line to a transfer line; and a control mechanism disposed in each secondary flushing line, wherein the control mechanism is operated by a difference between up-flow isobutane pressure and down-flow transfer line pressure.