Flowzone Engineering Solution

Neles™ capping valves

The Neles PZ series capping valve provides an automated solution for opening and closing batch digesters during the chip fill process. By improving efficiency and operator safety, this valve significantly enhances the chip fill process within the digester.


  • The Neles PZ capping valve enhances plant efficiency by automating the valve’s open/close operation, which reduces filling time.
  • These valves facilitate safe operation and full automation of the digester chip fill process, which enhances productivity and improves operator safety.
  • The rapid return on investment is due to the increased productivity and minimal modification required on existing digesters.


  • Metal-to-metal seating provides exceptional sealing performance, which translates into long-lasting tightness and low maintenance costs.
  • The PZ capping valve features a compact design that incorporates safety interlocks through two pressure sensors mounted on the valve body. These sensors prevent unintentional valve operation when the digester is pressurized.
  • The valve’s lower flange is custom-made to match the digester’s top flange, which simplifies installation on existing digester vessels.


  • Pulping
  • Chip fill process


Full bore ball valve
Size range
Size range: DN 500 and 600 / NPS 20” and 30”, bottom flange modified in accordance to digester top flange
Pressure classes
PN 16 & ASME 150
Temperature range
up to +200 °C / +390 °F


  • Technical Bulletin
  • Installation, maintenance, and operation brochure
Scroll to Top