Collaborative Project for new butterfly seals

Freudenberg Sealing Technologies and its French Customer Definox developed high-performance, hygiene requirements compliant butterfly seals

  • March 2, 2021
  • New high-performance seals for butterfly valves from Freudenberg Sealing Technologies
    New high-performance seals for butterfly valves from Freudenberg Sealing Technologies

Freudenberg Sealing Technologies, in conjunction with French customer Definox, a manufacturer of first class process valves and stainless steel equipment for high-end applications, first developed a new series of high-performance seals for butterfly valves. Following passing of rigorous tests, and the successful delivery and deployment of the 70 EPDM 291 O-rings both companies decided to launch a project for the development of new butterfly seals.

Setting out the objectives

Amongst the set technical targets were simple installation, uncompromising tightness, wear-resistant materials and sealing geometry free of dead space. After the final conception, the development team at Freudenberg Sealing Technologies set to work. 

Test and validation phase

The advanced test benchat Freudenberg Sealing Technologies is a CIP system featuring multiple containers, which has the capability of simulating various cleaning processes with acids, lye or disinfectants. Analysis is provided on the material’s resistance and functional reliability, thus delivering vital data for selecting the optimum seal geometry. 


Among the attributes of the new butterfly valve seal is its ability to close with little force. Moreover, when closed, the seal creates high compression to ensure the sealing function. The seal’s geometry is free of dead space to guarantee its suitability for use in hygienic applications. It also demonstrates very good pressure resistance, which is maintained during multiple switching operations, and extremely low torque. As a result of these properties, long service life and high reliability are assured, even when operating in challenging conditions.

Material components

As a result of this project, Definox now offers a series of butterfly valves available in three FDA- and EU (Reg.) 1935/2004-compliant materials: 75 EPDM 253356; 75 Fluoroprene® XP 41; and 75 HNBR 254067. 75 Fluoroprene® XP 41 is additionally tested in vitro, according to USP chapter 87. The material is also certified to USP Class V chapter 88 at 121°C, meets 3-A® Sanitary Standards and complies with regulations set out by the BNIC (Bureau National Interprofessionnel du Cognac) in France.