4. Conclusion

For general applications, industrial valves will continue to evolve towards quarter-turn actuated valves, i.e. :

• to ball valves for small sizes (DN = nominal diameter < 80 mm) ;

• to butterfly valves for larger sizes : DN > 65 mm.

This outlook is due to :

• the ease with which these taps can be controlled (both automatically and manually);

• their sealing performance (100% leaktight) and flow performance (low or very low head losses);

• flexible pipe connections (3-piece ball valve, etc.);

• the small size of butterfly valves and the possibility of installing them between flanges (wafer...);

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