Pressure Relief Device Valve PRD for Transformers

The transformer pressure relief device valve PRD is designed for use in liquid immersed transformers in order to release excess internal pressure that is caused by a system’s failure.
Therefore the pressure valve maintains the tank’s integrity. In addition to the operating limits of EN 50216-1, the device is capable to be installed in any position on the tank walls and cover, in any inclination and without any alteration of its opening performance. There can be mounted also more than one pressure relief device PRD on each transformer.
The device has threaded connection G 1” according to UNI-ISO 228. Body and cover are out of brass, O-Rings Viton, all other parts are made of stainless steel, A2 quality.

The pressure relief device PRD is set and fixed on customer request within the standard range from 30 kPa up to 50 kPa, in steps of 5 kPa, with a tolerance of -5/+7 kPa. The fixed setting is stamped on the body of the device.

Pressure relief valve PRD - working principle

The working principle of transformer pressure relief device PRD is very simple. If pressure arises inside a transformer and exceeds a pre-set pressure limit, the pressure safety valve PRD opens its valve clap, which is held by a spring and releases the internal pressure until it declines. After decrease of the pressure, the pressure valve clap moves back to its origin position and closes completely. Normally, the pressure relief device valve PRD will be mounted on top of the transformer. Due to internal faults, it is suggested to have such pressure relief valve to protect the transformer and release arising pressure quite suddenly.

Pressure relief device valve PRD available sizes

  • Pressure relief device PRD 1"
  • Pressure relief device PRD 1 ½"
  • Pressure relief device PRD 2"

Pressure valve properties upon request

  • Low temperature for up to -60 °C
  • Made of seawater resistant aluminum for offshore applications
  • With sealing holes
The transformer pressure relief device valve PRD can be fitted with a protection cap out of PA6 to prevent unauthorized operation. Our PRD devices meet the requirements of EN 50216-5 as well as IEC 60076-22-1.
For further detailed information please refer to downloads below.

You might also be interested in!