Pressure Relief & Control

Qualitrol PRDs are used across the full spectrum of transformer installations—from network transformers (500 kVA and above), large distribution and medium power units, through to large power transformers and load tap changers. They offer precise, reliable pressure relief for equipment operating in utility, heavy‑industry, mobile, and railway environments. Their directed‑flow designs and optional piping systems help ensure hot oil is safely redirected away from personnel and critical components.

Mechanical over pressure protection device with integrated directional discharge outlet. Provides pressure relief and insulating fluid containment (requires optional piping) on transformers and load tap changers during over pressure conditions. Automatically reseals once pressure has fallen.

• Dual spring loaded valve for quick operation and reseal after a pressure situation

• 50% higher flowrate than the LPRD for increased tank protection during an over pressure event (12600 SCFM)

• Utilizes the same bolt pattern as the LPRD and industry standards enabling direct replacement

• Standard integrated directional shield with 8 inch diameter outlet to maximize flow rate and control hot oil and gas discharge

• Reduces risk to environment, surrounding assets, and people in the immediate area when used in conjunction with piping kits

• Variety of optional piping kits, flanges, and animal screens are available from Qualitrol to divert hot oil

• Operating pressure, Gasket material, indicator style

• Up to 2 latching or momentary switches (single or double pole form C, high DC, or low current gold contacts)

• Electrical connection style

• Gas bleed system

• Stainless steel piping and body option

The Qualitrol LPRD is a mechanical pressure relief device engineered to protect transformers and load tap changers from excessive internal pressure. Featuring a patented dual-gasket system for rapid response and automatic resealing, the LPRD offers visual and remote operation indication, optional alarm switches, and directional shielding for safe discharge of hot oil and gases. With over 50 years of field-proven reliability, it remains the industry standard for transformer overpressure protection.

• Patented dual-gasket system for fast response and reliable resealing

• Up to 4 Form C contacts with only 2 switch enclosures

• IP65-rated switch enclosure standard; IP66 available with AS1000 switch

• Visual operation indicator pin and optional semaphore

• Rugged die-cast flange with corrosion-resistant coating

• Directional shield for controlled hot oil/gas discharge

Utilities and heavy‑industry operators face operational, environmental and safety risks due to sudden internal transformer faults that cause pressure spikes. Qualitrol’s PRDs solve these challenges by offering:

• Improved personnel safety through controlled directional discharge

• Reduced environmental impact by enabling discharge to containment

• Reduced downtime thanks to reliable automatic resealing

• Extended asset protection via fast‑acting mechanical design
  

These solutions address safety compliance, environmental obligations and asset‑life optimisation.