403 - Contamination & Filtering Flashcards
Contamination is
The enemy to modern hydraulic systems.
Types of Contamination
Solid
Liquid
Gas
Solid contamination
Dirt
Metal from welding and grinding
Wear of pump
Liquid contamination
Water from condensation
Gas contamination
Entrained air from loose hose
Vaporize the oil at high temp
At what size micron do we start testing?
15
At what size do we start in removing?
5
Human eye can only see down to how many microns?
40
1 micron, micrometer =
.001 m
.0000039”
What percent of all hydraulic oild is contaminated?
90% and you can’t see it.
ISO/NAS Codes
Are the measure of particles/particulate per a specific volume of fluid
28/18/11
28 would be the total # of particles
18 would be the # under 15 microns
11 would be the # under 10 microns
Higher the Cleanliness #:
The dirtier the oil
Sources of Contamination:
Built in during manuf. and maintenance. Tank Leakage Air through the breather Dirty new oil - worst Problem Pump wear Piping Scale - piping needs to be honed after extruded Dirt on rods due to broken seals
What percent of wear and failure is contamination related?
70-90%
Collapse Pressure
Point at which element filter media fails.
Beta Stability
Beta Ratio remains at a relatively constant level at high pressure drops beyond ormal element operating ranges.
Beta 100 Stability means:
Beta Ratio at the rated micron will not drop below Beta Ratio 100 until 250 psi is reached.
Poor Beta Stability causes:
Significant loss of filter efficiency through element life. Loss of Equipment. Increased wear and component failure. Increase in downtime. Decrease in customer satisfaction.
Absolute Rated Filter
Bx>=75
Beta Ratio, eff, and dirt holding capacity determinded by conducting a multipass test.
All absolute filter elements are depth type filtration.
Nominal Rated Filter:
No industry standard exists to determine nominal element ratings. Suface filtration (nominal) applied in actual systems can not achieve dirt holding capacities derived through multipass testing.
