When filtering aggressive chemicals and solvents it is imperative to choose the correct base material, coating or surface modification.
Fluoropolymer coatings can be applied either in powder or liquid form and offer a largely chemically inert coating some 50-100 microns thick with excellent temperature resistance and desirable properties such as FDA compliant top coats.
Their easy application to a wide variety of geometries combined with relatively low cost (compared to exotic alloy construction or surface treatments) makes them an attractive proposition in principle.
Despite their superb chemical resistance, simple fluoroplymer coatings do have some weaknesses, primarily their permeability and susceptibility to damage that limit their useful life in service before repair or replacement is necessary.
All fluoropolymer coatings are microporous which means that the process fluid permeates over time, eventually reaching the substrate, resulting in blistering and delamination of the coating, and chemical attack of the substrate.
The coatings themselves are also vulnerable to damage from mechanical handling, particularly so in the case of a filter housing which is regularly opened for change out and requires careful handling to avoid damage when inserting or removing the filters.
As a result of operation experience Amazon Filters offers, depending on size of filter, two different types of advanced fluoropolymer coating using novel technologies to mitigate as far as possible the limitations of simple fluoropolymer coatings.
Read our Application note for more detail about Fluoropolymer coatings for housings.