TABLE OF CONTENTS A modern hydraulic system must be highly reliable and provide greater levels of accuracy in its operation. The key to this is the requirement for high precision-machined components. Cleanliness of the hydraulic fluid is a vital factor in the efficient operation of the fluid power components. With the close tolerance design of pumps and valves, hydraulic systems are being made to operate at increased pressure and efficiency levels. The cleanliness of the fluid is an essential prerequisite for these components to perform as designed and also for higher system reliability and reduced maintenance.
The worst enemy of these high-precision components is contamination of the fluid. Essentially, contamination is the presence of any foreign material in the fluid, which results in detrimental operation of any of the components in a hydraulic system. Fluid contamination may be in the form of a liquid, gas or solid and can be caused by any of the following:
The contaminants here include metal chips, bits of pipe threads, tubing burrs, pipe dope, shreds of plastic tape, bits of seal material, welding beads, etc.
During the operation of a hydraulic system, many sources of contamination exist. They include moisture due to water condensation in the reservoir, entrained gases, scale caused by rust, bits of worn-out seal material, sludge and varnish due to oxidation of oil.
The main...
