Kunkle Relief Valve Model 91

Cast iron liquid relief valve

Bronze trim, with pressure-tight cap. Variation “03” for field adjustability.

Product Features

  • Extra heavy, rugged construction
  • Bolted bonnet permits easy inspection and servicing without removal from system
  • Springs are steel with plating for corrosion protection
  • High lift, wing-guided disc offers high relieving capacity
  • Pivot between disc and spring corrects misalignment and compensates for spring side thrust
  • Quality cast iron body and bonnet, insert and disc are available in either bronze or stainless steel and lapped for optimum performance


  • Sizes 1 1/2″ to 6″
  • Suitable for maximum back pressure of 60 psig
  • Pressures from 5 to 400 psig
  • Temperatures from -20°F to 406°F
  • Options: Stainless steel trim, female x female NPT connections, inlet and outlet flanges per ANSI B16.1 – 125#, epoxy-coated internal body and bonnet for corrosive environments


  • Liquid


  • Overpressure relief, protection, and pressure regulation of pumps, tanks, lines, and hydraulic systems
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