Polymer melt filtration apparatus

摘要

A polymer melt filtration apparatus comprising a closed upright cylindrical vessel divided by two horizontal pipe plates into a small lower product distribution chamber with a product inlet at the bottom, a small upper product collecting chamber with a product outlet at the top, and a large middle chamber connected to a heat carrier fluid circuit. A plurality of closely spaced heat exchanger pipes are mounted in the middle chamber between the pipe plates and surrounded by heat carrier fluid, each pipe enclosing a filter cartridge detachably connected at its upper end to said pipe and radially spaced therefrom to form an annular space around each cartridge. A series of narrow channels are provided between the upper end of the annular space and the upper collecting chamber to impede the generation of dead zones inside the annular space and the collecting chamber. The main polymer melt stream flows inside the pipes through the filter cartridges. A very small amount of polymer passes through the channels, about 0.03 to 3.0 wt. % of the weight of the stream. This filtration apparatus and process provide accurate temperature control of the polymer melt and uniform residence time. Each individual filter cartridge is easily changed and cleaned without cooling down of the whole apparatus and it is not necessary to remove the whole filter assembly.