Selecting Filtration Cartridges

There are SO MANY different filtration cartridges out there. How do you select the right one? Here at MAC Water Technologies, we hope to make the decision easier for you.

Another common issue is buying cheap filtration cartridges that cost companies an incredible amount of money. We all see it; the purchasing department makes a decision to buy a cheaper filter which, in the end, will end up costing more money. Cartridge filter selection is one of the top culprits of inefficient filter systems. So you want to be sure you select the right model for you or your business.

For instance, our engineers may cringe when they see a bag filter or string wound filter in an industrial setting. These cheap filters can end up being very expensive for operating costs and they probably aren’t right for your industrial system. Let’s take a look at the types of filter cartridges so you can see what best fits your water filtering needs.

Types of Filtration Cartridges

Bag Filters

Bag filters look like a bag and if used correctly are mainly used for collecting large solids. The only way to look at these is as a tighter strainer–do not look at these like a sediment filter. Bag filters have the least amount of surface area and the surface area is what does the actual filtering. Also, smaller particles will penetrate the bag making micro holes that turn into larger holes.

String Wound Filters

String wound filters are filters basically made out of string and wound tightly together. These are very inexpensive, however, they do not have much surface area. For the most part, string wound filters are typically good for slimy applications. Slime coats the filter and then it needs to be changed, which is why the cheap cost of string wound filters comes in handy for this use.

 If you purchase a more expensive filter for the same type of slimy application, you’ll have to replace it once slime coats the filter like before, but the cost for these uses makes them not worth the money.

Polyspun Filters

Typically your polyspun filter will be a depth-style filter. Depth-style means that the outside has large pores and the inside has smaller pores. While these filters do not have much surface area, they do have the advantage of depth. With the lack of surface area in mind, it is important to use these on low flux applications. Flux is the flow rate per area of the filter. Small particles in a high flux application on polyspun filters will penetrate the filter making micro holes. Just like above with bag filters, these micro holes will end up forming larger holes. 

A typical mistake made when using depth filters is that the filter-housing was originally designed for a pleated filter, and the purchasing department replaced the pleated filter with a lower cost polyspun; this happens often on reverse osmosis applications. 

An easy way to test to see if your polyspun filter is good for the application is, after it needs replacing, cut the filter in half long-way and see how the filter is loaded. If it is uniform, you have the right poly filter. If it looks clean with a dirty section, try a different style.

Pleated Filters

Pleated filters have the highest amount of surface area and have the highest flux ratings. On basic particle filtration applications, pleated filters will remove 3-5 times more solids than polyspun filters. Therefore, if they are less than 3 times more expensive, they are the lowest operating cost solution. When shopping around, look at surface area differences versus cost differences. Unless there is a unique reason to use a different filter, price compare using surface area.

NEED HELP?

In addition to the above, it is often cost-effective to use multiple filter cartridge styles in a series within your system. The experts at MAC Water Technologies can show you the numbers so you're able to make an educated decision about your filtration needs or other services required.