Sealing technology manual for the process industry - Cleaning process

The cleaning methods at a glance • CIP (“Cleaning In Place”) is the fully-automatic cleaning without disassembly of the equipment • COP (“Cleaning Out of Place” or “Cleaning Open Plant”) re- fers to cleaning after disassembly, opening of the plant, etc. • SIP (“Sterilization In Place”) is the sterilization, either with peracetic acid, hydrogen peroxide (“cold sterilization”), or with hot steam • WIP (“Washing In Place”) requires partly manual work (brushing, scrubbing etc.) in some places • WOP (“Washing Out of Place”) means the complete dis- mantling and cleaning of the plant by hand • OPC (“Open Plant Cleaning”) is the external cleaning of a plant without disassembly A typical cleaning procedure consists of seven steps: 1. Pre-rinsing to roughly remove product residues (with cold or warm water, depending on the product) 2. Cleaning with an alkaline cleaner (sodium or potassium hydroxide), plus various additives (surfactants, complex- ing agents, anti-foaming agents etc.) 3. Flushing out the alkaline detergent with water 4. Acidic cleaning to remove, e.g. limescale (phosphoric acid or nitric acid as well as additives) 5. Flushing out the acid with water 6. Disinfection for elimination of microorganisms (peracetic acid and/or hydrogen peroxide mixtures, alternatively us- ing steam) 7. Final rinsing with water of drinking water quality or higher, depending on the application CLEANING PROCESS Among the most important requirements when designing a seal is not only the resistance of the sealing material to the product itself in which the seal is used, but also the compatibility with various cleaning agents and steam tem- peratures of up to +140 °C (+284 °F). The aggressive cleaning media on the basis of acid, alkali and peroxides pose to some extent even greater challenges for the sealing mate- rials than the product medium itself. In addition, the high cleaning temperatures exacerbate the effects of the media on the material. Materials resistance and purity 60

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