Pipes and fittings in food process engineering.

Pipes and fittings used in food process engineering must satisfy the requirements of DIN standards. In order to avoid hygiene problems and to achieve a sufficient product quality, it is necessary to be able to clean pipe systems effectively. Taking this priority into account, criteria may be postulated for the design of pipe systems (for example no dead volume, no gaps) as well as for the surface conditions of pipes and fittings. The importance of stainless steel, its behaviour and means of measuring its roughness are discussed. Changes in roughness in terms of cleanliness are noted by electrical changes. The value of the surface potential depends mainly on the pH of the product, the passiveness of the surface and the type of surface finish. Differences between electrical adsorption and hydrophobic adsorption are discussed. Characteristics of materials suited to food piping and fittings applications are briefly mentioned. Pipe cleaning is carried out using the CIP Process using alkaline and oxidizing acid solutions. (from English abstracts)