ABSTRACT
This chapter discusses the practical ways to determine when processing equipment needs to be cleaned, what level of cleaning effort is needed, and how to accomplish the cleaning. It also discusses the ways to determine the source of particle problems and a method for reducing the frequency of major equipment cleaning efforts by purging with inert gases. The general philosophy of equipment cleaning should be that the minimum time and effort is spent to solve the particle problem. Major-effort equipment cleaning methods generally involve disassembly of the equipment and inspection and cleaning of each of the individual parts. A third factor to consider in the choice and handling of purge gases is whether the flow of the gas is laminar or turbulent. Turbulent flow will favor particle entrainment from surfaces because it reduces the boundary-layer thickness.
