- Silica Gel Breather Definition: A silica gel breather is a device used to filter moisture from the air entering a transformer, protecting its insulation.
- Air Flow Mechanism: Transformer oil expansion and contraction cause air to move in and out of the conservator tank, necessitating filtration.
- Moisture Absorption: Silica gel effectively absorbs moisture from the air, ensuring the air entering the transformer is dry.
- Dust Filtering: The oil seal cup in the breather traps dust particles, preventing them from contaminating the transformer oil.
- Color Change Indicator: Silica gel crystals change from dark blue to pink as they absorb moisture, indicating when they need to be replaced or regenerated.
Silica Gel Breather of Transformer
Whenever an electrical power transformer is loaded, the temperature of the transformer insulating oil increases, consequently the volume of the oil is increased. As the volume of the oil is increased, the air above the oil level in conservator will come out. Again at low oil temperature; the volume of the oil is decreased, which causes the volume of the oil to be decreased which again causes air to enter into conservator tank.
Natural air contains moisture that can mix with transformer oil and harm its insulation. It is crucial to filter this moisture out. A silica gel breather is the most common method for this purpose.
Silica gel breather for transformer is connected with conservator tank by means of breathing pipe.
Construction of Silica Gel Breather
The silica gel breather for transformers is simple in design. It is a container filled with silica gel that air passes through. Silica gel absorbs moisture very well. Freshly regenerated gel can dry air to a dew point below -40°C, while well-maintained gel usually operates at around -35°C.
Working Principle of Silica Gel Breather
Silica gel crystals absorb moisture very effectively. As air passes through the breather, the crystals absorb its moisture, ensuring dry air reaches the conservator. Dust particles in the air are trapped by the oil in the oil seal cup. The oil acts as a barrier when there is no airflow. Silica gel crystals change color from dark blue to pink as they absorb moisture.
When there is a significant pressure difference between the air inside the conservator and outside, the oil levels in the seal adjust. This movement allows air to pass from the high-pressure to the low-pressure compartment, filtering out dust from the outside air.
