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Crosby™ Balanced Diaphragm Crosby™ Balanced Diaphragm
While bellows have been traditionally used in pressure relief valves where variable backpressure is present, over time they may become compromised—potentially contributing to fugitive emissions and product loss while posing a safety risk for systems and operators.
Reduce Maintenance Costs,</br>Improve Reliability, Increase Safety, </br>& Lower Emissions

Reduce Maintenance Costs,
Improve Reliability, Increase Safety,
& Lower Emissions

The Crosby J-Series with Balanced Diaphragm technology minimizes these risks by replacing the bellows with a flexible reinformed elastomer diaphragm. Diaphragms are inherently more resilient for higher backpressures and rapid pressure cycling applications. As a result, our new technology extends the backpressure limits to 80% of set pressure and increases the Kb factor up to 15%—expanding the application range of spring-loaded PRVs.
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The Crosby Balanced Diaphragm Checks All the Boxes

    Reliability: Robust design ensures balanced operation
✓    Productivity: Extends backpressure handling while improving Kb factor
✓    Safety: 100x more resilient than metal bellows for high frequency cycling
✓    Environment Friendly: Maintains reliable protection against fugitive emissions
    Cost Effective: Yields long-term cost savings relative to traditional PRVs with bellows installed
How It Works

How It Works

The diaphragm effective area subjected to back pressure has the same area as the nozzle seating area, ensuring balanced operation. Its location is above the guide and not in the main flow path of the media. Therefore, it reduces exposure to the media, improving reliability and valve flow performance. Additionally, the absence of bellows removes its spring rate effect, enhancing stability during operation.

The Crosby Balanced Diaphragm Difference

  • 20% greater back pressure handling improves reliability during back pressure 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
  • Same springs as JOS valves reducing spare parts and inventory costs
  • Cycle, burst, and fire tested and independently witnessed by Lloyd’s Register
  • Easily convert existing Crosby J-Series with Balanced Diaphragm upgrade kits
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