摘要 |
Abstracted side stream (2) entire, or divided into at most (n-1) side streams (2a-c) is delivered directly to at most (n-1) pinions (3a-c) of a planetary gear pump (3) with n pinions (3a-d). Simultaneously, unmixed additives (4) are supplied directly to other, nth pinion (3d). Side stream, now mixed with additives, leaves centrally from pump, to be reintroduced into the main polymer melt stream. Preferred features: n is 3-8. The side stream passes through a static mixer (6) before reintroduction into the main stream. Unmixed additives are supplied centrally into an inlet of the pump. |