Thread: A timely warning.

Far out, thats incredible. Both of our compressors at work have a dedicated brick and concrete room with steel mesh doors.

I remember as a work experience kid, I think it was every week the business used to drain their air compressor so it didn't rust internally also.

Originally Posted by Slunnie

Far out, thats incredible. Both of our compressors at work have a dedicated brick and concrete room with steel mesh doors.

I remember as a work experience kid, I think it was every week the business used to drain their air compressor so it didn't rust internally also.

It used to be a daily chore on trucks. Nowadays the air system has dryers that regularly blow off the moisture.

Diving tanks I filled up in a water tank of concrete for when not if one went boom. HP air is great yet wow. Do not buy or use cheap is a rule plus with high pressure tools. My last tank is unable to be filled any more boo hoo.

Probably a good time to post " mandatory requirements for your pressure equipment" in Australia. Now air receivers, I take it that means our 12v compressors for pumping up our tyres, as well ?

A disclaimer ;

DISCLAIMER: The statements, views and opinions presented in this article are those of the author. Asset Management Engineers Pty Ltd does not warrant the correctness of the information provided or its fitness for any purpose.

Periodic Inspection frequencies according to AS3788:
External and internal periodic inspection frequencies from Table 4.1 of AS3788, for some of the more common types of pressure equipment are –

• Air Receivers* – External 2 years & Internal 4 years
• Refrigeration Vessels* – External 2 years & Internal 12 years
• Accumulators* – External 2 years & Internal 12 years
• Above ground LPG gas vessels* – External 2 years & Internal 10 years

*For 2 yearly inspection certificates to remain valid, annual checking / testing of pressure relief and safety devices is required.





Pressure Vessel Inspections | AME (asseteng.com.au)

Originally Posted by Slunnie

I remember as a work experience kid, I think it was every week the business used to drain their air compressor so it didn't rust internally also.

Draining is more to stop water buildup which reduces the capacity of the receiver. Once drained it's leftl moist inside so rusting still happens unless you can somehow dry the inside of the receiver.

I remember working at a company and using a small JunAir silent compressor (like they use in dentists). I decided to drain the tank and got over 5 litres of rusty water out of it !
It had been used for testing something over a period of weeks then put back on the shelf without draining !

If you're lucky a bit of oil carryover from a cheaper compressor helps stop the rusting, just make sure you have a good filter system on the outlet.


Colin

While he is obviously sincere in his analysis of what caused the tank to rupture, I think that he is a bit off the mark with some of his conclusions.

For a start, as mentioned in another post, the thickness of that steel appears to be from left over food tins! He points out where he suspects that the fault propagated from, which to me points to a faulty section of welding, nothing to do with corrosion. In use, the continual pressurising cycles over a period of time will cause a faulty weld, or any other weak point, to become even weaker.

I fail to see how wriggling the small ring pull on the relief valve proves ANYTHING! At one time working offshore I had to sign off on these things after testing, and we sure as hell did not just wriggle the stem and see if you could lift it!

Yes, the tanks should be drained regularly, even better if left open when not in use with those small units. He is also correct with his comment of tanks being a much better option if mounted vertically. Also, better not to have them close to where you are using them, but then what is the use of a portable air compressor if you can not take it to where you need the air.

In another post, it is stated that:

Draining is more to stop water buildup which reduces the capacity of the receiver

Really! You would need a damn lot of water to make any appreciable difference to the capacity of the tank. Anybody that has done any spray painting will tell you that the most important bit of equipment is some form of water trap and or filter on the tank outlet line to the spray gun.
It is not possible to stop moisture entering the receiver without some elaborate filtering, which is beyond the scope of what happened here.

Originally Posted by Old Farang

In another post, it is stated that: Draining is more to stop water buildup which reduces the capacity of the receiver

Really! You would need a damn lot of water to make any appreciable difference to the capacity of the tank. .

Did you read the rest of the thread ??
I drained 5 litres from a tank of about 10 litres so that maybe reduced the capacity a bit......

Having worked in the pneumatics industry for years I've come across receivers almost full of condensate. Most companies nowadays fit auto drains on a timer, roughly every hour the drain is opened for a few seconds. Alternatively a float operated drain can be used.
When I first started in industry most large companies had a dedicated guy who looked after lubrication of machines, drained receivers, drained filter/regulator bowls etc. That role no longer exists so draining of receivers has changed to 'automatic' but not on small DIY compressors.


Colin