Many fluid power systems fail simply because there is too much contamination in the medium. In fact, some estimate that 75% of all fluid power failures can be attributed to contamination issues.
There are multiple reasons why fluid can become contaminated. Use and wear of the components, poor plumbing, and contamination brought in with new fluid (or new components) are just a few of the possibilities. This is why no fluid power system can be complete without the use of a filter. Hydraulic filters keep the hydraulic fluid contaminant free.
There are a few different alignment options available for filters.