White Paper: How To Insure The Right Finish For Mixers Used In High Purity and Sanitary Processes

By Admix, Inc.

Admix Inc. (Manchester, New Hampshire) has extensively used stainless steel alloys to fabricate mixing and blending equipment for the dairy, food, beverage, cosmetic and pharmaceutical industries. Admix recognizes that, in order to meet the high standards of purity and cleanliness demanded by the pharmaceutical and biopharmaceutical industries, it is necessary to use 316 stainless steel as the material of construction for not only the wet end portion of the mixer, but also for portions of the drive end, which may include the motor, bearing frame or gear box.

It is also important that the surfaces of the mixers and blenders are smooth and clean, to minimize microbial contamination, reduce erosion corrosion and prevent the adherence of particulates to the surfaces of the equipment. The required surface characteristics may be obtained by electropolishing or by using either a mechanical or chemical treatment. Without question the smoothness of the surfaces of mixers and blenders are of concern and therefore, as part of the fabrication of their mixers and blenders, Admix routinely mechanically polish, electropolish and passivate those surfaces that contact the materials being processed.

A comprehensive inventory for sanitary standards and accepted manufacturing practices for the dairy, beverage and food processing industries has been established by 3-A Sanitary Standards Incorporated (3-A SSI) [1]. Accredited by the American National Standards Institute (ANSI), the 3-A guidelines for hygiene, safety and manufacturing practices are consistent with those established by agencies such as the USDA-Dairy, USDA-AMS and AG-Canada. The 3-A symbol displayed on process equipment shows compliance with those established standards, with regard to the materials of construction, design and fabrication. New P-3A standards are being developed specifically for the pharmaceutical and biotechnology industries and are expected to be issued within the next year.