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Keystone Series 36/37 High Performance Butterfly Valves
Series 36/37 High Performance Butterfly Valves
The K-LOK unique shaft packing is composed of 3 rings of braided PTFE rope between one PTFE V-ring at the top and bottom.
The packing operates on an interference fit with the body sealing in pressure and vacuum.
Keystone Series 36/37 High Performance Butterfly Valves


ABS, CRN, SIL capable
End Connection
Lugged, Wafer, Double Flanged
Dirty Service, Desalination, Cruise Ship, Cooling Water , Compressors , Chillers , Blowers, Biofuels, Balance of Plant, Steam Utility Distribution
Super Duplex, Stainless Steel, Duplex, Carbon Steel, 316L Stainless Steel, 316 Stainless Steel
Pressure Class
Process Connection Type
150RF, 300RF
Seat/Seal Type
High performance
Shutoff Class
Zero Leakage
ASME B16.34, API 609
Valve Size
NPS 12 / DN 300, NPS 10 / DN 250, NPS 14 / DN 350, NPS 16 / DN 400, NPS 2 / DN 50
Valve Size Standard
Valve Type
High performance Butterfly Valve, Butterfly
Specialty Gases, Aggressive Liquids/Gases, Air, Air, Inert Gas, Ammonia, Fuel Oil, Hot Water, Light Oil, LPG, Mineral Oil
Adjustable packing, Live loaded


  • K-LOK polymer and elastomer seats provide bi-directional, drop-tight shut-off in vacuum as well as at full rated differential pressure. Its unique design does not rely on pressure to assist sealing therefore seals at high and low pressures, as well as di
  • Blow-out resistant shaft is standard on all valves for increased safety.
  • Unique packing design allows for use in pressure as well as vacuum without modification or special assembly.
  • Disc taper pins are tangentially positioned half in disc and half in shaft, placing them in compression rather than shear, which eliminates potential for failure.
  • Rocker-shaped gland bridge compensates for uneven adjustment of gland nuts reducing packing leaks.
  • Integrally cast disc position stop perfectly locates the disc in seat, achieving maximum seat and seal life.
  • Extended neck allows for 50 mm (2") of pipeline insulation.
  • Integrally cast mounting pad provides direct mounting of actuators eliminating the need for costly brackets and couplings.
  • Flattened body bore at shaft journal ports positions shaft bearings near disc, providing maximum shaft support resulting in reduced wear and longer life.