Wikipedia gives the following:

Filtration is a physical, biological or chemical operation that separates solid matter and fluid from a mixture with a filter medium that has a complex structure through which only the fluid can pass. Solid particles that cannot pass through the filter medium are described as oversize and the fluid that passes through is called the filtrate. Oversize particles may form a filter cake on top of the filter and may also block the filter lattice, preventing the fluid phase from crossing the filter, known as blinding. The size of the largest particles that can successfully pass through a filter is called the effective pore size of that filter. The separation of solid and fluid is imperfect; solids will be contaminated with some fluid and filtrate will contain fine particles (depending on the pore size, filter thickness and biological activity). Filtration occurs both in nature and in engineered systems; there are biological, geological, and industrial forms.

In a short and clear form, we would say that you are inserting a barrier inside of a liquid stream with a certain pore size. This barrier keeps out solid contamination larger than its pore size, avoiding it to go downstream. The pore size is rated at a certain micrometer. 1-micron pore sizes won’t allow particles larger than the given 1 micron to pass through, in general.

Filters do come in all kinds of shapes and forms. EF-Filter focuses on gradient depth style filter elements, utilizing high quality polypropylene yarn, which has a extremely good compatibility with water. The diamond-shaped setup of the media enables the water to flow through and the fine particles to stick to the media, thus removing it from the water stream.

Micron Rating

In order to give you an idea what correlates to a certain micron rating, check below overview:

Let’s take a human hair: still visible by the human eyesight and already as big as 50 – 70 micron. Particles sized at 1, 5 or 10 micron are impossible to detect without the help of equipment.


Next to micron rating, there is also something like the Beta-Ratio or efficiency rating. In basic the Beta-Ratio tells you how many particles of a certain size will pass through the filter media. For example, if you have a 99% rated filter element @ 5 micron, this relates to a Beta-Ratio of 100 out of 100.000 particles sized at 5 micron, only 1.000 particles will go through, meaning 99.000 particles will be captured by the filter.

Overview for your reference:

Beta Value Efficiency # PreFilter # PostFilter
2 50% 100.000 50.000
10 90% 100.000 10.000
20 95% 100.000 5.000
100 99% 100.000 1.000
200 99,50% 100.000 500
1000 99,90% 100.000 100
5000 99,98% 100.000 20

Depth Style Filtration

Depth filters use the full media pack to retain particles throughout that medium, rather than just on the surface of the medium. These filters are commonly used when the fluid to be filtered contains a high load of different sized particles because, relative to other types of filters, they can retain a large mass of particles before becoming clogged. has developed superior depth filtration technology that can be used in a wide variety of liquid applications. This technology of highly engineered blend of polypropylene yarn fibers is wounded around a polypropylene core in a diamond shape to provide optimal efficiency, high dirt loading, larger flow capabilities and less start-up pressure drops.

Visualize how it works

To visualize how a depth style filter works, look at the picture.

As you can see the contamination is coming with the water stream from the outside of the element towards the inner core. Along the way the wounded polypropylene yarn is capturing solids particles of different sizes throughout the media.

Overall, the EF-Filter team wants to make the products available to you as a consumer directly. These products, which we have been supplying into several different industries, are high quality filters, based on a long history in not just the manufacturing of these filters, but also big experience with satisfied industrial end users.