A customer of us, asked us to replace some coarse filters (metallic housings with an hand-made inner modified filter element) applied in lubricating circuits on big compressors used in a refrigeration plant. He wanted to replace them with new filters , utilizing standard cleanable filter cartridges with a better filtration ratio, dimensioning them in a way to obtain a longer cartridge life.
We dimensioned the new filter system choosing a four time filtration area to elongate the cartridge working life. What we didn’t keep in mind was the filtered fluid compatibility. We discovered that the lubricating oil, coming in contact with ammonia pumped from the compressors, tended to damage the filter cartridges.
We solved this problem by using the same filter cartridges but realized entirely in stainless steel, with bottom ends welded, not glued. After three years, the system is still running with no problems.