Humidity and impurities reduce the dielectric rigidity of the transformer insulating oil and contribute to the forming process of smudges thus impairing the correct operation of the transformer itself.
The intake air of transformers should therefore be filtered and dried dehumidified by means of an equipment specially designed for that purpose and called Eco Gel Air Breather.
This equipment consists of a hollow, medium thick plate transparent cylinder which contains the eco gel, of a stainless steel housing, flanged at its top and bottom ends with light aluminium alloy blank flanges provided with appropriate threaded openings and connected among them by means of screw bolts. The bottom flange is fitted with a removable tank which is filled, when ready for operation, with transformer oil up to about half the height of the oil level check glass. In this tank there is a hollow aluminium cylinder whose bottom end is immersed in the oil of the tank, while at its top end protrudes into the gel cylinder and is provided with a horizontal ring of holes. The compound oil tank and the hollow aluminium cylinder constitute a siphon, that is a hydraulic trap which prevents direct contact of the gel with the ambient air as long as the transformer operates at constant temperature. When suction takes place, air is admitted under filtering action into the transformer owing to the difference in pressure prevailing under such circumstances. Under inverse operating conditions, the excess air is exhausted by the same way bubbling through the oil. The intake air opening is located at the bottom of the equipment, thus avoiding all possibilities of rain water entering in it.
There are several sizes of this equipment containing an eco gel quantity ranging from 0,5 to 10 Kg. The air intake opening is moreover fitted with a filter cartridge which prevents the entering into the equipment of whatsoever material.