Built-in Contamination

Metal shavings left in cross drillings,thread sealant, solvents, small pieces of welding slag and metal particals generated from fitting installations are some examples of built-in contamination. Each new component installed in a system can contribute the this type of contamination. Below are are some examples.

• Reservoirs - paint chips, welding slag, solvents and rags left in reservoir
• Pumps - burrs, thread sealant, sand(from casting), solvents and flushing solutions
• Control Valves - burrs, thread sealant, teflon tape, sand(from casting), solvents and flushing solutions
• Pressure and flow control valves - burrs, loctite, teflon tape, sand(from casting), solvents and flushing solutions
• Cylinders - rags, tools, burrs, seal material(from improper installation)solvents and flushing solutions, welding slag
• Hoses - anything airborn that can enter the hose while in storage, pieces if internal tubing generated while pressing on fitting
• Pipe - rust

Prevention

• Assemble components in a clean environment
• Remove pipe plugs in housings during overhauls, flush with solvent and blow air through all cross drillings
• Making sure new reservoirs are free of paint chips, rust, dirt, weld slag, burrs, tools
• Blowing air through and capping conductors before storing
• Flush manifolds repeatedly, blow air through all ports and passages and wipe clean with a lint free rag
• Thoroughly deburr pumps and cylinders and make sure component is free of welding slag
• Keep all components, including conductors, free of rust
• Only use seals and packings that are compatible with the fluid medium
• Use only clean lubrication or oil for assembly