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HBC Series

The Flowserve Limitorque HBC series of worm gearboxes are designed for quarter-turn butterfly, ball, and plug valve applications. They are also used for quarter-turn and multi-turn dampers.




Conventional steam, geothermal, combined cycle, concentrated solar power, downstream processing, basic, waste water, agriculture, steel and primary metals, food and beverage


Power, oil and gas, chemical, water, general industry

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Limitorque’s HBC series worm gear operators excel in diverse applications. Their dependability has been proven in the most demanding situations, ranging from nuclear power plants and large damper operations, to power plant flue gas desulphurization.

Equipped with a handwheel, the HBC can be used to manually operate butterfly, plug, and ball valves. Combined with a Limitorque electric actuator (such as the SMB, L120, or MX), the HBC provides powerful and responsive motorized operation. These combination actuators have a wide range of output speeds and output torques to 93,000 ft-lb (126,100 N m). HBC operators feature an optional 360° worm gear for use in guillotine damper and radial gate applications. Whether manual or motorized, you can depend on the HBC for easy valve control — even in tough installations.

Spur gear attachments increase your options. The HBC can be equipped with an optional spur gear attachment to further reduce input torque requirements. This makes it possible to operate even high-torque valves with a handwheel. Motorized applications can also incorporate spur gear attachments to reduce input torque requirements. Adding this would allow you to use smaller, less costly actuators to operate the valves. To achieve specific operating/stroke times, please inquire about alternative spur gear ratios.

Expand control capabilities with a motorized operation. The HBC can easily handle valve positioning and modulating tasks when matched with a Limitorque electric actuator such as the L120, SMB, or MX. The HBC is used not only in quarter-turn applications but in 360° output for use with manually operated and motorized multi-turn devices. For example, guillotine dampers and radial gates.


  • Broad application versatility provided by the ability to actuate a wide range of devices, both manually or motorized, at a considerable range of output speeds and torque
  • High strength and durability provided by ductile iron housing and roller bearing supported shafts and drive sleeve
  • Weatherproof, temporary submersion, and buried services available
  • Splined valve shaft adapter
  • Nuclear-qualified with SMB actuators or as stand-alone gearboxes
  • Self-locking gearing
  • Increased uptime due to bronze worm gear paired with alloy steel worm shaft
  • Lower maintenance costs due to heavy-duty construction; proven in use for more than 50 years to be rugged and dependable
  • Ease of operation made possible by valve position pointer, which makes at-a-glance position checking easier than ever

Call us today at (708) 388-3232

24-Hour Emergency Service

Our associates are available when you need them. We can respond by providing emergency parts, machining, or on-site technical expertise. We specialize in servicing actuators, that have malfunctioned electronically or mechanically, causing system shutdown or redirection. We aim to get you back in business as soon as possible.

Call our 24-hour line at (630) 989-3231