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Crosby™ J-Series Direct Spring Pressure Relief Valves
J-Series valves provide high quality and dependable overpressure protection for air, gas, steam, vapor, liquid and two-phase applications in one simple design.
Now available with two new to the world technologies, Balanced Diaphragm and Bellows Leak Detection.


  • ASME/NB certified capacities for air, water and steam.
  • Full compliance with all major global pressure relief standards including ASME VIII, XIII, API 526/527, EN4126 and PED/CE.
  • Highly customizable to meet most applications.
  • Interchangeable parts to reduce maintenance costs.
  • Full nozzle configuration.
  • Simple and reliable design for easy maintenance.
  • Soft seat options for superior seat tightness.
  • Adjustable blowdown to reduce product loss.
  • Restricted Lift available.
  • Wired or Wireless Relief Monitoring available.
  • Crosby™ Balanced Diaphragm
    • 20% greater backpressure handling improves reliability during backpressure surges.
    • 15% improvement in Kb factor enables sizing of smaller and/or fewer valves.
    • 100x more resilient than metal bellows for high-frequency cycling, ensuring safety.
    • Easily convert existing Crosby J-Series with Balanced Diaphragm upgrade kits
  • Crosby™ Bellows Leak Detection available
    • Instant notification of bellows rupture allows effective maintenance protocol.
    • Detection of small ruptures, from 0.0009in2 (D orifice).
    • Ensured balanced operation after bellows rupture enhances safety.
    • Leakage volumetric calculation in real-time for risk assessment and decision making.
    • Over 90% reduction of leakage through bonnet vent.
    • Easily enhance existing Crosby J-Series with Bellows Leak Detection upgrade kits.