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what is the color of silica gel when recharge is required?
Blue
Pink
Light blue
light pink
Pink
Silica gel acts as a desiccant in transformer breathers to absorb moisture from the air entering the conservator tank. When the silica gel is dry, it is blue, and it turns pink upon reaching its moisture-holding capacity, signaling that it requires recharging or replacement.
Silica gel acts as a desiccant in transformer breathers to absorb moisture from the air entering the conservator tank. When the silica gel is dry, it is blue, and it turns pink upon reaching its moisture-holding capacity, signaling that it requires recharging or replacement.
CoCl2тАЛ(Blue)+6H2тАЛOтЖТCoCl2тАЛтЛЕ6H2тАЛO(Pink) тАФ Chemical reaction showing hydration and color shift
The color change is caused by a chemical indicator, typically Cobalt Chloride (CoCl2тАЛ), impregnated into the silica gel beads. In its anhydrous state, CoCl2тАЛ is deep blue, but it transforms into a hydrated complex CoCl2тАЛтЛЕ6H2тАЛO in the presence of moisture, which exhibits a pink color.
Silica gel is used in the breather of a transformer to remove moisture from the inhaled air.
Moisture causes transformer oil to degrade, reducing its dielectric strength.
Recharging is done by heating the pink silica gel at approximately 120┬░C until it regains its original blue color.
Modern environmental-friendly silica gel often uses methyl violet as an indicator instead of Cobalt Chloride.
Visual indication allows for easy maintenance scheduling
High moisture adsorption capacity
Reusable through simple thermal regeneration
Requires manual inspection or color-based monitoring
Traditional Cobalt Chloride is considered toxic/carcinogenic
Transformer breathers
Compressed air dryers
Protecting sensitive electronics from humidity
The silica gel breather is connected to the conservator tank of the transformer.
Option A (Blue) represents the dry, fresh state.
Options C and D are incorrect as the color transition is specifically from deep blue to pink.
B is correct тАФ Silica gel turns pink when it becomes saturated with moisture and requires recharging via heating.
Always remember that the color shift indicates the moisture level; blue = dry (safe), pink = wet (needs action).