NAF – Duball DL Ball Valve
Manual NAF-Duball DL full-bore ball valve with handwheel and flanged ends for isolation and control in industrial process services.
NAF – Duball DL Ball Valve
NAF – Duball DL Ball Valve
NAF – Duball DL Ball Valve
Manual NAF-Duball DL full-bore ball valve with handwheel and flanged ends for isolation and control in industrial process services.
NAF – Duball DL Ball Valve
NAF – Duball DL Ball Valve
MOC

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

NAF

NAF – Duball DL Ball Valve

Applications: Chemical & Synthetic Fuels Oil & Gas Pulp, Paper & Cellulose

High-Performance Full-Bore Isolation and Control The NAF-Duball DL is a full-bore, metal or soft-seated ball valve engineered for isolation, on/off and modulating control in demanding industrial services. Its...

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About NAF – Duball DL Ball Valve

High-Performance Full-Bore Isolation and Control

The NAF-Duball DL is a full-bore, metal or soft-seated ball valve engineered for isolation, on/off and modulating control in demanding industrial services. Its split-body construction, spring-loaded stem packing, and bidirectional sealing deliver reliable shut-off and stable operation, even with difficult media and high differential pressures. A blowout-proof stem, rigid seat designs, and a robust torque path ensure consistent performance, while the off-centre body joint enables fast seat and ball replacement without removing the actuator. With direct mounting of the NAF-Turnex actuator and full integration with the NAF-D30 intelligent positioner, the Duball DL provides a compact, vibration-resistant valve package suitable for severe service across chemical, pulp & paper, mining, petrochemical and power applications.

For technicians, engineers and production managers, this means:

  • Reliable long-term sealing – Spring-loaded stem packing provides stable, maintenance-free operation in automated and control services.
  • Consistent shut-off under demanding process conditions – Floating ball design delivers bidirectional tightness, even with challenging media.
  • Reduced downtime during shutdowns – The off-centre body joint allows seat and ball replacement without removing the actuator, simplifying maintenance.
  • Stable torque transmission – Blowout-proof stem with long foot minimises backlash, ensuring predictable operation and accurate control.
  • Flexible trim and material options – Reinforced PTFE seats, Alloy 6 metal seats, sealed or scraper designs, and high-temperature variants address a wide range of duties.
  • Optimised for automation and control loops – Direct mounting of NAF-Turnex actuators and optional NAF-D30 positioners creates a compact, vibration-resistant valve package.
  • Improved process stability in high-energy applications – Optional Z-trim reduces cavitation and noise, protecting downstream equipment.

Our Valve Repair Centres in Secunda and Durban provide expert repair, reconditioning, automation and testing services, ensuring that your NAF-Duball DL valves remain in peak condition.

Robust design. Stable operation. Lower maintenance effort. 

Download the NAF-Duball DL Technical Bulletin

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Contact us Today – Tel: 0861 103 103

Valve Repair Services

SeriesDuball DL
Design

Split Body Floating Ball

Features
  • Rigid split-body construction – Provides mechanical stability under high pressure and thermal cycling, maintaining accurate alignment of internal trim components.
  • Floating ball design – Engineered to provide consistent seating behaviour across varying differential pressures and process conditions without excessive wear.
  • Precision-machined ball and seat interface – Ensures smooth rotational characteristics and predictable torque requirements throughout the full travel range.
  • Robust shaft support – Stem supported by durable bearings that minimise friction and mitigate shaft vibration, contributing to stable actuator performance.
  • Heavy-duty seat options – Reinforced PTFE, spring-loaded, scraper and Alloy 6 metal seats allow configuration for corrosive, abrasive or high-temperature services.
  • Optimised flow path – Full-bore design reduces pressure drop and turbulence, improving energy efficiency and supporting high-capacity isolation duties.
  • Direct actuator mounting platform – Designed for seamless mounting of NAF-Turnex actuators, reducing mechanical play and improving control loop responsiveness.
  • Fire-safe construction available – Fire-safe versions tested to API 607 and ISO 10497 provide compliance for hydrocarbon and high-temperature applications.
  • Versatile material selections – Carbon steel, stainless steel, duplex and specialty alloys support demanding chemical, pulp, mining and petrochemical conditions.
  • Service-ready internals – Internal components are configured for ease of access, ensuring efficient inspection and replacement during planned shutdowns.
Size
Range

DN 25 – 400 / 1” – 16”

Pressure
Rating

PN10 – 40 / ANSI 150 – 300

Temperatures-30°C to 250°C
End
Connections		Flanged
Body
Materials

Carbon steel WCB / Stainless Steel CF8M / Alloy steels / ASTM A351 CG8M (317) / ASTM A351 CG3M (317L) / Duplex EN 1.4470 / 904L and many others

Seat
Materials		R-PTFE / SS + Alloy 6 overlay / Duplex + Alloy 6 / Solid Alloy 6
Ball
Materials		SS / SS + Hard Chrome / SS + Alloy 6 / Duplex + Alloy 6 / Solid Alloy 6
Options &
Accessories
Applications

Isolation, on/off and control for chemicals, pulp, hydrocarbons and steam in the Chemical Processing, Pulp & Paper, Synthetic Fuels, Oil & Gas and Refining industries throughout Southern Africa

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