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Dehydrating Breathers

Oil Level Indicators for Transformers

Our oil level indicators for transformers are used for hermetically sealed and for distribution transformers with expansion tank. They are suitable for indoor and outdoor use.
 
The oil level indicator displays if air bubbles have remained in the transformer, if gas has been generated because of an internal failure or if there is a leakage at the transformer tank. Depending on the oil level indicator type, the oil level can be displayed either directly or by means of a leakage-proof magnetic clutch. We have types with vertical float movement for the use on transformer covers or types for the horizontal use at expansion tanks in program. Float movement of the oil level gauges for power transformers as well distribution transformers with expansion tank can be either radial or axially chosen.

Oil level indicator types for transformers

We are a leading german manufacturer of oil level gauges for transformers and put a lot of efforts in continuously developing special designs matched with customers requirements.

For more detailed information, please refer to the respective brochures on the product pages.

The transformer is surrounded by moist air. As long as the temperature of the cooling and insulating liquid does not change, no ambient air sucks in or sucks out.

The cooling and insulating liquid in the transformer cools down, the transformer sucks in humid ambient air through the conservator. The drying agent extracts moisture from the inflowing air and ensures that only the dried air will be aspirated into the transformer.
The temperature inside the transformer increases. The cooling and insulating liquid expands and displaces the air. The air in the expansion vessel escapes through the conservator and passes the dehydrating breather.
If the dehydrating breather is used properly, no moisture will remain in the transformer, which can lead to condensation any damage.

Transformer dehydrating breather – Silica gel

As a drying agent, we only use silica gel due to the good adsorption properties.The drying crystals are minimum 3mm in size. In activated condition they have a orange crystalline appearance as they absorb moisture the colour changes to colourless, beginning at the bottom and spreading progressively to the top.

Functional check of silica gel

The indications of proper function of the transformer dehydrating breather during changes of temperature are as follows:

  • Rising air bubbles in the oil bowl
  • Colour of drying crystals changing from orange to colourless beginning at the bottom and spreading slowly upwards

In order to completely exclude any possibility of moisture reaching the conservator, the drying agent should be renewed when there is still a layer of active orange crystals approximately 5 cm thick at the top.

Regenerating the drying crystals

Drying crystals which have absorbed moisture can be regenerated by heating to a temperature of 120-130 °C. A temperature of 140°C should not be exceeded otherwise hydrogen chloride gas will be given off by the colour indicator that could combine with the moisture present to form a dangerous hydrochloric acid.

For more detailed information please find downloads mentioned below.

Dehydrating breathers - General information

Download

Data sheet silica gel - sorbead orange chameleon

Download

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