Dehydrating breathers are body frames filled with moisture-absorbing stuff – silicagel.
Air coming in or out through vent pipe from non-hermetic transformer, container filled with oil or any other hygroscopic liquid passes dehydrating breather filled with silicagel. Silicagel absorbs moisture and prevents oil dampness.
Due to construction of a dehydrating breather air passes through oil hydraulic lock that keeps mechanical particles away from transformer/container and prevents silicagel from long contact with ambient air. As far as silicagel is getting damped the granules of indicating silicagel are changing their colour. Possible colour variants are described in the manual.
The following types of dehydrating breather mounting are possible: screw-, flange-, top-, bottom- or side mounting.