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Compressed air line corrosion

Compressed air line corrosion

Compressed air line corrosion

We have a compressor installed under a train where we use the compressed air to operate different equipment (e.g. door, brake, etc). We notices there are lot of corrosion in the air lines far away from the compressor (at the opposite end of the train). We are suspecting condensation formed when the ambient air is surrounding the pipe is too cold. We are thinking about putting insulation around the air line to prevent condensation from forming. Is it a valid method? Any experience with this? Any suggestion for the insulation material for compressed air line?


RE: Compressed air line corrosion

The compressed air is normally super heated, in this respect there should be no concern.
It is when air contacts the wall of the pipe that condensation occur. The wall temperature should be at ambient.
If you are in cold climate, something heat tracing and insulation is applied.
How cold is cold, well you would need to look at the margin between dew point temperature discharge gas and minimum ambient.

RE: Compressed air line corrosion

Do you mean corrosion from condensation inside the air line or outside?

Insulation is only of use if there is sufficient flow in the line to maintain a high enough temperature. Even very thick insulation will transmit heat over time and result in a cold pipe which then condenses the air.

Other option is trace heating or use stainless steel or galvanized pipe.

Or dry your air to below the ambient air temp.

There are many forms of insulation, but for somewhere exposed to water, mist, ice etc, you really want either a closed cell insulation or some sort of solid rubber type material.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Compressed air line corrosion

Insulation will not prevent condensation at all times, as mentioned by LittleInch.

Another option is to mix some oil for pneumatic tools in the compressed air lines to prevent corrosion by forming a thin protection layer on metal surfaces and emulsify water. A thin mineral oil in mist form with good oxidation stability, lubricating capacity for valves etc, good anti-corrosion properties and capable of emulsifying water could be a solution.

Depending on operating conditions (environment, freezing) alternative fluids may be preferred. Biodegradable lubricants will rapidly fall apart in non harmful substances when coming into the environment, when freezing is a problem a thin lubricant based on polyalkylenes ("PAG") can be used. It will work as a kind of "antifreeze" to prevent water freezing and can also available in biodegradable.

If a lubricant is used on a passenger train, it may also be necessary to install some extra air outlet piping to prevent lubricant contact with clothes etc.

RE: Compressed air line corrosion

Add a simple knock out pot and PSA dryer on the wet compressed air line if you can find the space for this kit.

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