Depth versus Surface filtration: What is the difference?

By August 4, 2021 Blogs, Latest News No Comments

When determining whether to employ depth filtration or surface filtration, it is critical to understand the fluid you’ll be filtering. The fundamental distinction is that in surface filtration, particles are generally maintained on the medium’s surface, whereas in-depth filtration, particles are either in a thicker media or in numerous layers of media that make a tortuous path.

What is Depth Filtration, and how does it work?

Imagine a path with numerous layers to better understand how depth filtration works. Water mediums flow through the strata at varied speeds and sizes depending on what they are made of. Larger particles, for example, will be found closer to the surface because their size allows them to move more freely than finer components, which can only enter from the side or bottom due to their lower size. Because the medium layer is thick, small particles cannot travel through it as easily as thicker ones, and instead become stuck behind its “walls,” where irregular pores present extra difficulties for even those who might otherwise succeed in escaping.

Surface Depth filtration

Depth filtration is often used in polishing filtration applications such as:

  • Clarification of essential oils and extracts • Blood fractionation operations to recover plasma • Haze removal in distilled spirits • Filtration and removal of water from transformer oil • Bulk Chemical Production • Large-scale Parenteral Solutions

What is the definition of surface filtration?

Surface filtration is a method of removing particles from the surface that is commonly employed in water filtration systems. The particles that are kept create a material layer known as a “cake layer.” The cake layer, which is generated when trapped particles form a thin film over time, aids in the efficiency of this process.

Before chemical or biological treatments, like chlorine disinfection, surface filters are often utilised. Because the surfaces of the filters can’t survive severe chemicals, surface filtering happens first. They nonetheless play a vital role in removing any large fragments that might have clogged the final filter stages otherwise.

What Is the Difference Between Surface and Depth Filtration?

Particles are mostly kept on the surfaces of media and retained as a layer in surface filtering. Because there is more filtering material to catch waste, efficiency improves. Multiple layers or thicker materials are used in-depth filtering to provide an intricate path for other things that shouldn’t be released into a water supply, such as dirt and chemicals, to pass through. The fundamental distinction is that in-depth filtration, particles are trapped in a tortuous path, whereas in surface filtration, particles are largely held on the surface.

It is worth noting that there is no universal or industry standard for “nominally” rated filter media. Each manufacturer chooses their material according to the criteria and definitions of what comprises the term, thus if you’re comparing prices, one filter maybe more expensive than another depending on the method used by different manufacturers.

Which is the best option for you?

Depth filtration is more expensive than surface-level filtration, but it lasts longer. The filter mechanism you choose depends on how you intend to use it – if your source has a lot of trash and requires heavy-duty filtering, depth will be required. Start with something less expensive, such as manual cleaning or sand filters, if all else fails. You may later determine that depth filtration is the best option for your application.

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