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Keystone Series GRF Butterfly Valves
Series GRF Butterfly Valves
A heavy duty double flanged concentric design resilient seated butterfly valve
Keystone Series GRF Butterfly Valves


Body Design
Short Pattern
316 Stainless Steel, Buna-N, Carbon Steel, Ductile Iron, Epdm Rubber
Operating Temperature
Up to 250 F (120 C)
Pressure Class
Process Connection Type
125FF, 150FF, CL150RF
Seat/Seal Type
Shutoff Class
Zero Leakage
API 609, ASME B16.34
Valve Size
NPS 24 / DN 600, NPS 30, NPS 36, NPS 40, NPS 42, NPS 44, NPS 48, NPS 56, NPS 60
Valve Size Standard
Valve Type


  • Double flanged body design with face-to-face dimensions, according to EN 558 Series 20, API 609 and AWWA C504 short.
  • Designed according to EN 593 and API 609.
  • The seat is field replaceable and fully isolates the body and shaft from the flow.
  • Primary shaft sealing exceeds the pressure rating of the valve and prevents leakage through shaft area to atmosphere.
  • A secondary shaft sealing provides back-up safety.
  • A molded-in O-ring in the seat for flange sealing eliminates the need for gaskets.
  • Shaft seals prevent moisture penetrating into the shaft area.
  • Rounded polished disc edge gives full concentric sealing, lower torques, longer seat life and drop-tight shut-off.
  • Extended body neck allows for pipe insulation.
  • Top and bottom shaft bearings for optimized support and minimum friction and decreased torque.
  • Top bushing absorbs actuator side thrust loads.
  • All valves comply to Pressure Equipment Directive (97/23/EU) Module B1 + D, CE Marking.