Kunkle Relief Valves Models 230, 330, 330S, and 333S

Relief valves for air and gas services with models to ASME section VIII, gas “UV,” National Board certified and PED certified for non-hazardous gas

Product Features

  • Lightweight aluminum construction is resistant to environmental and internal corrosion
  • Repetitively consistent opening pressure
  • Smooth relief action
  • Positive reseating with minimal pressure drop
  • Soft seat option provides repeatable leak-tight performance, allows reduced maintenance costs, multiple cycles with tight shut-off and high seating integrity (Models 330, 330S, and 333S)
  • Model 230 (non-code) is direct spring-loaded design with synthetic disc insert
  • Model 330 series’ differential mechanism maintains a predetermined seat contact load
  • Full spring load is never imparted so synthetic disc insert (Models 330, 330S, and 333S)
  • Seat tightness increases as inlet pressure approaches set (opening) pressure
  • Each valve tested and inspected for pressure setting and leakage


  • Connections: Threaded NPT or SAE
  • Temperature range: -20 to 185°F (-29 to 85°C)
  • Pressure ranges: Model 230: 300 to 1500 psig (20.7 to 103.4 barg); Model 330: 1000 to 5500 psig (69 to 379.3 barg); Models 330S/333S: 1000 to 7500 psig (69 to 517.1 barg)
  • Max back pressure (Model 333S): 100 psig (16.9 barg)
  • Codes: ASME VIII and PED


These valves are suitable for use on multi-stage high pressure compressors intercoolers and after coolers, on high pressure receivers and storage bottles, for thermal expansion relief and on breathing air pac and SCUBA recharge compressors.

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