Qualitrol 900/910 Rapid Pressure Rise Relays (RPRR)


Patented mechanical device for detection of sudden pressure events based on the rate of pressure rise and safe limits established by transformer manufacturers. When a dangerous pressure rise has been detected, the Qualitrol rapid pressure rise relay (RPRR) will change state. This can be used as an alarm or trip signal to minimize the potential of transformer tank damage.


  • Models designed for use in oil or gas space
  • 100% tested for pressure rate release point
  • Protection and detection of dangerous sudden pressure changes
  • Devices calibrated to quickly alarm or trip during rapid pressure rise changes
  • Actuation only occurs based on rate of pressure rise and will not occur under normal pressure variations caused by temperature change and vibration
  • Can be subjected to full vacuum or 20 psi positive pressure without damage
  • Standard operation from -40 to 180°F ( -40 to 82°C)
  • Special units available for operation at -67°F (-55°C)
  • 100% factory calibrated and tested to ensure performance
  • Units are serialized and calibration records maintained
  • Factory tested for switch (contact) performance and response
  • Field test kit available for simple GO/NO-GO test to assure proper functionality of the device
  • Multiple mounting and calibration options for gas or oil applications
  • Flange or thread mounting options available for vertical or horizontal mounting
  • Models calibrated for proper response in gas or oil space applications
  • From the original creator of mechanical rapid pressure rise relays
  • Original creator of patented bellows technology for mechanical rapid pressure rise detection
  • Over 25 years of experience and refinement in rapid pressure rise protection with greater than 100000 units installed


  • Horizontal or vertical mounting
  • Seal in relay (QUALITROL 909) for latching alarm or trip signal
  • Electrical connection types, cable size, lengths and wire colors
  • Gas bleed system
  • Field test kit (KIT-013) and factory test fixture (FIX-601)
  • Flange or thread mounting
  • Stainless Steel

Group Created with Sketch. Applications

For transformer and other electrical apparatus protection. Device sends an alarm when a dangerous sudden pressure rise condition has occurred. This alarm can be used to trip the transformer offline preventing further damage or purely as an indicator of an event.

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