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SR Series

The Flowserve Limitorque SR series of spur gearboxes is designed for manual and motorized operation of gate and globe valves, and slide gates in tight space or high vibration applications.




Conventional steam, midstream transportation, downstream processing, water, waste water


Power, oil and gas, water

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SR series spur gearboxes are easily adapted for motorized operation by MX, L120 and SMB actuators.

The SR series spur gearboxes offer an extensive range of thrust and torque outputs for
multi-turn applications such as gate and globe valves, and slide gates. Applications for
weatherproof or temporary submersion (IP67) service can be accommodated. For manual
operation, spur gear attachments are available to reduce the input torque required,
resulting in lower handwheel rim pull for opening and closing operations.

The SR series ductile iron housing provides strength and durability. The drive sleeve, spur pinion shaft, and spur gear reduction shafts are roller bearing supported, delivering high mechanical advantage and long life. Excellent sealing of mating surfaces provides reliable environmental protection. Ambient temperatures to -35°C are achieved with the standard lubricant.


  • Weatherproof and temporary submersion construction (IP67)
  • Maintenance-free
  • Input flanges machined in accordance with MSS SP-102, with keyed input shaft
  • Mounting bases machined to MSS and ISO standards
  • Splined, bronze alloy stem nut is removable from the drive sleeve for thread machining
  • High strength spur pinion and ring gear
  • Roller bearing supported for high mechanical advantage
  • Ductile iron enclosure • SR_H series for high thrust and torque applications
  • Output thrust to 1 056 600 lbs (4700 kN)
  • Output torque to 27 290 ft-lbs (37 000 Nm)
  • -35°C to 90°C (-31°F to 194°F) temperature range for continuous operation (options to -50°C)

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