Silica Gel Breather of Transformer

Silica gel Breather is cylindrical type container which is fitted to the conservator tank through a pipe line which is totally filled with silica gel crystals used for absorbing any moisture present in the air during breathing action of transformer due to expansion and contraction of transformer oil in the transformer. The size of Breather depends on the volume of transformer main tank as well as quantity of transformer oil in the transformer. A oil pot is connected under the breather. The details of silica gel Breather is shown in figure.

Fig. 1 ( Before moisture absorbed )

Maintenance of Silica gel Breather

When the Silica gel breather is first installed, the crystals have a blue tint, and after a period of operation, the colour of the tinted crystals gradually changes to pink , this is an indication that the silica gel is becoming saturated and losing its absorbent properties. When there is a preponderance of pink crystals the silica gel should be changed or reactivated.

Fig. 2 ( after moisture absorbed )

Silicagel may be reactivated by heating in a thin pan at a temperature of 150⁰C to 200⁰C for two to three hours when the crystals should have regained their original blue tint.
Before filling the container with silica gel, clean and dry all parts of the breather. Verify that the oil level in the oil cup is correct or not –correct.
Finally ensure that the breather is not choked and is free for passage of air.