Apparatus and method for in-place cleaning of a mixer

摘要

An in-place flush-cleanable mixer system for mixing materials in a vessel. The mixer has an impeller connected to a mixer drive shaft, the impeller and shaft being mounted in an assembly which extends through an opening into the vessel and closes that opening. The assembly has a cylindrical hub with bearings which support the shaft and with an open passageway through which the shaft extends out of an open end of the hub. The open passageway is part of a confinement region which is terminated at its outer end by a confinement shell which separates inner and outer rotors of a magnet coupling. The inner rotor is connected to the mixer shaft, and the outer rotor is connected to a drive shaft. There are no dynamic seals which close the confinement region so that the working materials can be present throughout. Included in the assembly is a purge plate coaxially disposed and fitted with a closable port for introduction of flush cleaning materials and with an annular manifold and passages for distribution of the cleaning materials to the open passageway. Abutting assembly components have annular grooves at a periphery of their abutting faces and O-rings disposed and compressed within the grooves to prevent working or cleaning materials from entering the joints between the components and to provide easily flush-cleanable working surfaces at the joints. Bolts and screws within the confinement region are relieved at the periphery of the undersides of their heads and therein have O-rings compressibly retained to prevent entry of materials under the heads.