SMB Electric Actuators

Flowserve Limitorque SMB actuators are designed and built to provide years of dependable service in a wide range of environments.

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  • Brands:
  • Applications:
    Petroleum Production and Refining, Sewage Collection and Treatment, Tank Farm Transfer, Water Supply and Distribution (water), Boiler Circulation, Nuclear Service, Desalination, Filtration, Gas Production, Heavy Oil, Oil Sands and Shale, Molten Salt Transfer, Decoking
  • Industries:
    Mining, Oil and Gas, Power Generation, Wastewater Collection and Treatment, Water Supply and Distribution, Water Treatment, Nuclear Power

Whether direct-mounted to multi-turn valves, dampers or sluice gates, or side-mounted to HBC or PT worm gear reducers for quarter-turn applications, Limitorque SMB actuators deliver unsurpassed performance.

Introduced in the early 1960s, the SMB and the spring-compensated SB actuators for high-speed and high-temperature service are at work for the U.S. Navy, every nuclear power generating facility in the USA, and virtually every other industrial environment. With a rugged cast iron housing and precision-machined gearing,the SMB and SB actuators embody sensible design and solid construction.

From the extreme cold of the Alaskan North Slope to the extreme heat of North Africa and the Middle East, SMB actuators perform reliably year in and year out. For critical or demanding service conditions, trust the industry standard of excellence — SMB.


  • 50+ years of installed history
  • Unmatched durability, dependability and flexibility
  • Torque output to 60 000 ft-lb and thrust output to 500 000 lb
  • Fully qualified for nuclear applications to IEEE 384, 323, and 344
  • Weatherproof, explosion-proof and submersible constructions

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Limitorque HBC Series Worm Gear Operators Brochure

Limitorque HBC Series Worm Gear Operators brochure: Proven in the most demanding situations

Limitorque SMB Series Electric Actuators Brochure

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Brochure explaining the Limitorque SMB Series Electric Actuators, showcasing the durable construction for the toughest applications.

Limitorque SMB Series/SB Series Electric Actuators User Instructions (IOM)

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Limitorque SMB Series/SB Series Electric Actuators User Instructions: Installation and Maintenance Manual (IOM)

B320 Bevel Gearbox

Description: The Limitorque B320 series of bevel gear operators delivers efficient and dependable operation for multi-turn applications. Suitable for manually operated valves and gates or motorized operation with Flowserve Limitorque MX, L120 and SMB actuators.

HBC Worm Gearbox

Description: The Limitorque HBC series of worm gear operators excels in demanding applications, ranging from nuclear power plants to critical service flow control in hydroelectric plants. The HBC is suitable for manual operation or motorized with Flowserve Limitorque MX, L120 and SMB actuators.

WG Worm Gearbox

Description: The Limitorque WG worm gearbox provides reliable performance in a wide range of weatherproof, submersible and buried service applications. When motorized with Limitorque MX, L120 or SMB electric actuators, the WG offers unsurpassed quality and longevity for quarter-turn and multi-turn, torque-only applications.

MT Bevel Gearbox

Description: The MT series incorporates a rugged thrust base design ideally suited for torque-seated valve applications and applications involving elevated process temperatures. The MT may be combined with MX, L120 and MX actuators.

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