Chemical Technology October 2015

Adapting valve designs to meet industry’s exacting requirements

by Bryan Orchard

Hygienic diaphragm valves are needed for a wide variety of applications in the pharmaceutical and biotech sector. Having paved the way for reliable aseptic production with its unique design years ago, the SISTO-C series is continually adapted to meet industry’s increasingly stringent requirements.

I n sterile process engineering, such as in the production of insulin, vitamin enzymes or APIs (Active Pharmaceutical Ingredients highly potent agents), users place special de- mands on the hygienic valves that they use. This is particularly apparent in the exacting requirements regarding the produc- tion process and the materials. There is a noticeable trend here: “Operators are continually demanding higher quality materials. In the pharmaceutical sector, stainless steel grades such as 1.4435 are usually used. However, users are increas- ingly requesting 1.4359 and Hastelloy qualities,” reported Alfred Knöbl, product manager of the SISTO-C series at SISTO Armaturen SA Echternach, Luxembourg. “This is because these materials are far more corrosion-resistant. The valves are not necessarily affected by the cleaning liquids used in the CIP/SIP processes, but rather by fluids that are needed for product processing, for example after fermentation.” In old systems a lack of space was a common problem and it is also an issue in new biotech systems. This has given rise to the present trend of building production facilities in an increasingly compact way, often grouping together multiple valves as valve manifolds. As a result, many valve manifolds

are frequently installed under the tanks. Froma hygiene point of view, this new design offers nothing but advantages, as Knöbl explained: “The compact design reduces the neces- sary distances between the valves and eliminates dead legs in the piping.” Another trend that has an impact on the production pro- cess is the increasing use of very small nominal diameters. Typical nominal diameters used in the pharmaceutical sector range from DN 8 to DN 50; most are between DN 15 and DN 20. However, valves with a nominal diameter of DN 2 are also needed sometimes. “These are not laboratory applica- tions,” clarified Knöbl. “Producing such nominal diameters is a big challenge in terms of the production process.” For this reason, in addition to establishing new production processes at SISTO, the necessary measuring methods and quality monitoring systems were also set up. Very low flow rates are also needed in processingmethods such as chromatography, for example. Another particularity: these applications require a very high compressive strength in some cases and operating pressures of 20bar are quite usual. “In normal pharmaceutical production we have operating

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Chemical Technology • October 2015