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AIR DEHYDRATING BREATHERS

for distribution transformers

Air dehydrating breathers - 13658 Type TV74-5-6 and VE05

1. GENERAL INFORMATION Air dehydrating breathers are transparent hollow cylinder tubes which contain chemically pure silicium salt (silicagel) with coloured indicator. The air breathed inside the transformer due to the thermal contraction of the oil mass, passes through the silicagel. The silicagel absorbs the humidity, indicating the saturation degree by changing colour as follows: ORANGE silicagel completely dry. GREEN silicagel saturated with humidity. The salt contained in the breather, when saturated, may be easily removed and regenerated by heating it, inside a ventilated oven, at 120° - 150°C, until the colour becomes orange again. The specific property of the silicagel is its high absorption power of humidity. This is total until the salt has absorbed water for about 15% of its weight, and saturation is reached when the salt has absorbed water for 30 to 40 % of its weight. 2. TECHNICAL FEATURES The upper and lower parts are made in a non-porous corrosion-proof aluminium alloy casting. The hollow cylinder is made of plexiglass and it is protected by a stainless steel cylinder, with windows which allow the visual control of the silicagel colour. In the bottom side of the breather, an hydraulic valve prevents continuous air contact with the silicagel and allows the air to pass in both direction (inlet or outlet) only when there is pressure deficiency or excess inside the transformer. Pressure values for air passage into the dehumidifier are: 0.003 kg/cm2 inlet , or 0.005 kg/cm2 outlet. The hollow container and the hydraulic valve are separated by a drilled plate with a labyrinth system, which have the double purpose of diffusing inlet air uniformly, and of avoiding that any salt dust may damage the closing system. 3. AIR DEHYDRATING BREATHER TYPE TV75 & VE05 (page 5.40) They are small sized dehydrating breathers, particularly fit for assembling on small distribution transformers The type VE05 follows the same manufacturing principles of the bigger sizes like the type VE10. The type TV75 (or TV74) is the cheapest model of our breathers: its top flange is made in corrosion proof aluminium alloy. The silicagel housing is made of cellulose triacetate (cellidor by Bayer), suitable for mineral oil; only upon request, this breather can be fitted with a stainless steel cylindrical protection.
File : ACCESSORI DISTRIBUZIONE UNCONTROLLED COPY REV 03 dtd 10/10/08