Unity Industrial/Commercial Water Filtration Equipment

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Multi-Layer Filtration Facts

We make it a point to stay well informed about changes in our industry. If advances occur, we want to make sure our clients can have the benefit of them.

The last major change in technology was Multi-Layer filtration which took place in the early 1970's. I can discuss it at great length if anyone is interested, but briefly, it is filtration in the media, not on its surface. Therefore it has several very important advantages:

Multi-Layer filters remove literally pounds of dirt without clogging.
Multi-Layer filters don't unload dirt at high flow rates as screens and strainers do.
Multi-Layer filters don't build up pressure loss as screens and strainers do. So your water flow is not impeded.
The close contact in Multi-Layer filters, between the media and the water actually causes more dirt to be removed from the water. This is because two things work in our favor.
The media cause some of the dissolved iron in the water to oxidize in the filter, where it is filtered out.
In Nature there is a very small electro-magnetic attraction between all particles. It is what causes gravity. In physics these are called Van der Wahl forces. They cause the dirt particles to be attracted both to each other and to the filter media. In order for these forces to work, the flows cannot be violent. In the Multi-Layer filter the flow is very gentle because we have such a large volume of media for the water to flow through, so the filters works much better than if they were a screen or strainer with their very high violent forces.
Multi-Layer media is very strong and durable. It does not wear out and does not need to be replaced. Periodic backwashing is all that is required to keep it performing perfectly.

By contrast, all the new filtration processes which are touted as being improvements are based upon either screens or strainers. In other words, the water has to flow through holes in a thin manmade material. If a particle is too large to fit through a hole, it is filtered out. But that hole is then plugged, so as this process continues the water has fewer holes to flow through. Eventually (actually soon) it requires more and more pressure to push the water through the remaining holes. Either the flow is impeded, or the particle is deformed, and forced through the hole, into the "filtered" water. Because there is no depth below the surface to catch particles, which are forced through, the water quality will suffer until the screen is backwashed or is replaced causing an interruption in the filtration process. We have found that all the claims for these devices are based upon one of two things. Either they are filtering out relatively large rigid particles, such as sand, (the inventions from Europe and the Middle East are mostly of this type, apparently and not surprisingly, their water systems allow sand into the pipes, and they must irrigate much more than we do) or they use multiple cartridges. Some cartridges claim to filter "in depth" and they do, but the depth is only about 3/8" so the clogging takes place even sooner. And cartridges must be replaced when they clog.

None of these devices address the problem New Yorkers actually face. That is, a whole range of particle sizes, from visible pieces down to lots of tiny material, almost as fine as a dye, which shows up as brown color in the water. The brown color is a messy mixture of dirt and iron (rust). The iron actually causes staining by adhering to any surfaces with which it comes in contact. Multi-Layer filtration deals very well with the entire range of dirt and iron which come to it, automatically, without fuss, muss or operating cost.

So, all the new filters are really just the old ineffective technology, with new names or new claims, but the same drawbacks, and the same high operating costs. If really new technology is developed, we will be happy to present it to you.