9th Dec 2021

Membrane vs. depth filtration: the differences explained

There are two main filter types: membrane filters, and depth filters. Both have a wide range of different applications and uses, from pharmaceuticals to chemicals and coatings.

But before you invest, there are some key differences you need to be aware of. 

The key differences between membrane and depth filters

Membrane filters

Membrane filters are typically used for microorganism removal, as those membranes are validated against a specific microorganism rather than aimed at a particular particle size.

The pores in a membrane filter are incredibly small and tightly packed together, making them a great tool for complex filtration or as a final filter in your filtration chain. However, this means that the filter can get blocked quickly if large volumes of material are caught in its membrane.

While they can be used for particulate removal in some industries like pharmaceuticals, they are only suitable when there is minimal particulate loading in a solution. This is because they lack the depth and lifespan to handle large quantities of particulate. 

In these instances, employing a depth-type filter is usually a better option. 

Discover 4 exciting innovations that are improving filtration for chemicals  and coatings. View our infographic.

Depth filters

As the name suggests, depth filters use a porous filtration method to retain particles throughout the entire depth of the medium, rather than just holding them on the surface. Unlike membrane filters, depth filters don't have a defined pore size or structure.

These filters are commonly used when the fluid contains a high particle load, as they can catch and retain a larger volume of undissolved particulate before becoming blocked.

Depth filters are adept at dealing with a higher volume of particulate at variable sizes. Additionally, due to their larger, more forgiving structure, depth filters block less easily, are less expensive, have a longer lifespan, and are generally more flexible than their membrane alternatives. But while depth filters are more cost-effective than membrane filters, they can struggle to remove smaller particulate material.

Both filter types are better for different use cases, but there are some instances where you can substitute one for the other and still achieve the high-quality filtration you need. 

Case study: SupaPleat Plus Ink

While membrane filters are usually the preferred option for complex filtration, they're not always the best choice. Here's an instance where we partnered with a global ink manufacturer to provide a high specification depth filter that achieved the same quality filtration at a much lower cost. 

After undergoing extensive testing, we substituted an existing set of 0.45 µm Nylon membrane filters with our SupaPleat Plus Ink V grade depth filter.

The absolute rated hybrid pleated depth cartridges were specifically developed in collaboration with manufacturers of bulk digital ink. This was to reduce expenditure while maximising quality. 

The filter provided:

  • Ongoing annual savings

  • Higher dirt-holding
  • Batch-to-batch consistency
  • Equal effectiveness as the membrane equivalent

Let us help you choose the right filter

To get the most out of your filtration system, it's vital to know the differences between the two filter types, so you can pick the right one for your specific needs.

By partnering with an experienced filter manufacturer, you'll always know what filter is the best fit for your process. With access to industry knowledge, high-quality products, and ongoing service support, you can be certain that your filtration system will never let you down.

4 exciting innovations for chemicals and coatings filtration

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