Limitorque SMB Series: The “Legendary” Valve Actuator for Thermal & Nuclear Power

In the world of valve actuation, the Limitorque SMB Series by Nippon Gear is a global icon of unrivaled durability and performance. With a history of decades operating in the most demanding nuclear and thermal power plants, the SMB Series stands as the gold standard for applications requiring absolute safety and reliability.

Why is Limitorque SMB Series the Global #1 Choice?

1. Massive Torque Capability (Up to 27,000 N·m)

The SMB line offers 8 unit sizes to meet every load requirement, from light to ultra-heavy duty:

• Torque: Up to 27,500 N·m.

• Thrust: Up to 1,100 kN.

• High Compatibility: Works seamlessly with Gate and Globe valves, as well as quarter-turn valves (Butterfly, Ball) when combined with secondary gearboxes.

2. Intelligent & Safe Operating Mechanism

• Instant Electric/Manual Switch: Simply engage the declutch lever for manual operation. When the motor starts, the system automatically resets to electric mode, ensuring automatic operation priority.

• Ultra-Precise Torque & Limit Switches: Protects valves from overload and ensures precise stopping at any position in the stroke, preventing deviations thanks to the intermittent gearing mechanism.

3. Rugged “Heavy-Duty” Engineering

• Ultra-Durable Gearing: Bronze-aluminum alloy worm gears combined with Chrome-moly steel worm shafts, operating in a sealed housing immersed in extreme-pressure grease.

• Specialized Motors: High-torque, low-inertia design with multiple power supply options (AC/DC/Pneumatic/Hydraulic).

• Maximum Protection: Options for IP55, IP67 standards and rigorous Explosion-proof certifications (d2G4, ed3aG3…).

4. “Non-Disruptive” Maintenance

The smart design allows for easy component replacement without removing the entire actuator:

• Two-piece drive sleeve for easy replacement.

• Self-locking mechanism prevents the valve from falling freely even when the motor is removed for maintenance.

Applications in Key Strategic Industries

• Energy: Nuclear, thermal, and hydroelectric power plants.

• Oil, Gas & Chemicals: Areas requiring the highest explosion safety standards.

• Marine & Shipbuilding: Valve operation in corrosive seawater environments.

Technical Specifications Summary (SMB Series)