A candle filter(tubular filter) consists of cylindrical elements from various materials like metal, polymer, or ceramic. These candles are housed within a pressure vessel, where filtration occurs.
The candle filter design allows for high filtration efficiency, easy maintenance, and the ability to handle high flow rates and pressures.
▪ Filtration Process of Candle Filter
Feed Entry: The unfiltered liquid or gas, known as the feed, enters the filter housing.
Flow Direction: The feed flows through the candle elements from the outside to the inside.
Particle Retention: As the feed passes through the porous walls of the candles, solid particles are trapped on the outer surface of the candle elements. The clean liquid or gas moves through the candle walls and exits the filter housing.
▪ Cake Formation of Candle Filter
Over time, the trapped particles form a layer, known as a filter cake, on the surface of the candles. This cake layer aids in improving filtration efficiency by trapping finer particles.
The thickness of the cake layer increases until it reaches a point where the pressure drop across the filter becomes too high, indicating the need for cleaning.
▪ Cleaning Cycle of Candle Filter
Backwashing: A backwashing process is employed to clean the filter. During backwashing, a reverse clean fluid flow is introduced to dislodge the filter cake from the candle surface.
Cake Discharge: The dislodged cake is then removed from the filter housing, either manually or automatically, depending on the design of the filter system.
Resumption of Filtration: Once the cleaning cycle is complete, the filter returns to its normal operation, ready to filter more feed.
The candle filters provide a robust and reliable option for optimal filtration performance. Suit for high content and fine particles, corrosive, toxic, and odorous, and other harsh environments, automatic filtration.
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