A side-stream filtration system, permanent or on a portable cart, that draws oil from a reservoir, passes it through fine filters and often a water-removal element, and returns it, independent of the machine's main circuit. Running at low flow through very fine media, it can pull cleanliness codes down several steps. The name comes from the way kidneys continuously clean the blood.
Hang a kidney loop on the press reservoir, the ISO codes have been creeping up for months.
Also heard as
- kidney loop filtration
- offline filtration
- side-stream filtration
- filter cart
Related terms
ISO cleanliness code
Three-number code for how many particles above 4, 6 and 14 microns are in a millilitre of fluid.
Particle count
Count of solid particles per volume of oil, sorted by size, used to track dirt and wear debris.
Desiccant breather
Vent filter packed with drying beads that cleans and dries the air a gearbox or tank breathes in.
Top off
To add oil to bring a gearbox, sump or reservoir back up to its correct level.