Front view of NAF-ProCap capping valve designed for safe wood chip filling in batch digesters
Cutaway view of NAF-ProCap capping valve showing internal ball sector and seat design
Rear view of NAF-ProCap capping valve showing dual actuators for pulp digester sealing
Illustration of pulp digester process showing NAF-ProCap capping valve location at chip inlet
Front view of NAF-ProCap capping valve designed for safe wood chip filling in batch digesters
Cutaway view of NAF-ProCap capping valve showing internal ball sector and seat design
Rear view of NAF-ProCap capping valve showing dual actuators for pulp digester sealing
Illustration of pulp digester process showing NAF-ProCap capping valve location at chip inlet

M = Manual | O = On/Off
C = Modulating Control

NAF

NAF – ProCap Capping Valve For Pulp Digesters

Applications: Pulp, Paper & Cellulose

Safe Filling. Tight Shut-Off. Long-Term Reliability. The NAF-ProCap capping valve is specifically engineered for the demanding conditions found in batch pulp digesters, where safe, controlled chip filling and...

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About NAF – ProCap Capping Valve For Pulp Digesters

Safe Filling. Tight Shut-Off. Long-Term Reliability.

The NAF-ProCap capping valve is specifically engineered for the demanding conditions found in batch pulp digesters, where safe, controlled chip filling and reliable shut-off are essential for maintaining production uptime. Designed as a quarter-turn ball segment valve with heavy-duty materials, the ProCap ensures dependable operation during high-load cycles, pressure fluctuations and severe chemical exposure commonly encountered in the pulp and paper industry.

Its robust construction—including a reinforced hub design, welded Alloy 21 sealing surfaces and stainless steel body—provides excellent resistance to erosion, wear and thermal cycling. The ProCap’s eccentric ball segment is machined to deliver tight sealing performance and withstand the repeated mechanical stresses of rapid open/close cycles. Optional SIL-rated safety functions and independent “jammer” lock systems further enhance digester protection.

With direct actuator mounting and availability in large sizes up to 30–32 inches, the NAF-ProCap offers a compact, reliable capping solution that integrates seamlessly into modern or legacy digester platforms. From safety-critical isolation to efficient chip charging, it provides pulp mills with a durable, low-maintenance valve package designed for long service life under harsh operating conditions.

For technicians, engineers and production managers, this means:

  • Higher digester availability – Reliable shut-off performance supports stable batch cycles and reduces chip loss events.
  • Improved operator safety – SIL-capable actuation, secure locking systems and robust sealing lower the risk of unplanned openings.
  • Extended component life – Alloy 21 and reinforced hub/seat materials resist wear from chips, chemicals and high mechanical loading.
  • Reduced maintenance interruptions – Streamlined internal design minimises build-up, improves flushing and simplifies inspection.
  • Lower total cost of ownership – Durable construction and optimized sealing reduce replacement frequency and improve lifecycle performance.
  • Dependable performance under harsh conditions – Engineered specifically for pulp mill digester duties, not adapted from general-purpose valves.

Protect your digester. Secure uptime. Reduce risk.

Download the NAF-ProCap Brochure

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Contact us Today – Tel: 0861 103 103

Valve Repair Services

SeriesProCap
Design

Quarter turn ball segment

Features
  • Quarter-turn ball segment design – Provides high structural rigidity and reliable sealing performance during high-force chip loading cycles.
  • Eccentric ball segment geometry – Ensures progressive seat engagement and tight shut-off, reducing wear under repeated rapid cycling.
  • Reinforced hub and seat construction – Alloy 21 welded overlays provide exceptional resistance to erosion, corrosion and mechanical abrasion from wood chips and process chemicals.
  • Heavy-duty stainless steel body – One-piece construction improves mechanical stability and supports long-term dimensional accuracy under severe digester operating conditions.
  • High cycle capability – Engineered to withstand the repetitive open/close sequences typical in batch chip filling systems.
  • Large-bore availability – Manufactured in 28″, 30″ and 32″ sizes (700–800 mm) to match modern and legacy digester inlet requirements.
  • Multiple mounting arrangements – Direct mounting for pneumatic actuators and compatibility with SIL-rated safety systems for digester protection.
  • Optimised flange and inlet geometry – Designed to integrate with existing digester nozzles and accommodate thermal expansion without binding.
  • Improved flushing and cleaning behavior – Internal flow paths minimise chip accumulation, supporting consistent operation between batches.
  • High-temperature capability – Suitable for the thermal demands of digester environments, ensuring material integrity across operating cycles.
Size
Range

700mm or 800mm (Or customized) /28” or 32”

Pressure
Rating

PN 16-25 / ANSI 150

Temperatures-30°C to 200°C
End
Connections		Driiled & tapped / Flanged
Body
Materials

Stainless Steel 1.4408

Seat
Materials		Alloy 6
Ball
Materials		Stainless steel 1.4408 with Alloy 21 welded overlay
Applications

NAF- ProCap capping valve is used for the automated filling of wood chips in batch digesters in the pulp industry.

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