I will replace the final separator at my Bauer K14 and wondered if it was someone who had experience with this from the Aero-Dri Corp. sold by August Industries? August Industries Inc.
New final separator
- Thread starter Nordiver
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Yes. The Aero_Dry design is of the 1950's last sold surplus in the 1980's for the Joy compressors, also similar to the Davey compressor separator. Show me one not rusted up.
Most don't have an internal element and were used on HP air compressors but for jet engine starting never for breathing air. Incidentally most Joy units were 3500psi made in the 1970's
They are made of steel and Cadmium plated, good luck filling with cadmium poisoning an extremely dangerous material in HP breathing gas and banned on most breathing gas and air systems world wide.
These plated steel separators have a nasty habit of rusting up and rot out in a salt air environment. Don't but one buy three you will need them.
At $400 for a $30 1970's piece of junk like that someone is having a laugh.
For $450 you can have a modern 7075 separator with bronze element 4:1 safety 3/8 UNC fitting in stainless and shipped to the lower 48 states for $25.
Your call. Iain Middlebrook 
Graeme Tolton
Contributor
I have one of these, original to my 1982 davey compressor, no rust in or out. I have no signs of oil in the filter stacks, so it does work.
divingtactics
Contributor
I wouldn't buy anything second hand that I am going to fill to 200-300 bar - not worth the risk - you just don't know how many cycles it has been through. All filtration components have a finite lifetime and if they blow, they could take your life and or destroy your compressor - think hand grenade going off beside your compressor if you're not too concerned about your life.
Ian knows his stuff - go with his suggestion for a new one. We are fortunate to have such knowledgeable folk contributing to these forums.
Ian knows his stuff - go with his suggestion for a new one. We are fortunate to have such knowledgeable folk contributing to these forums.
Graeme Tolton
Contributor
The ones sold at august industries are new old stock.
Slipstrm
Contributor
I used one of these mechanical filters from an old Davey 2MC1a for 6+ years, I gutted it and filled it with 13x, fed the air into the bottom and out the top side port. No rust or corrosion ever seen in it.
I recently purchased a new Oceanus from Brian/August Industries and I also bought one of these new/old stock separators to add to my Filter stack the same way, gutted and filled with 13x. (I did have to do a good cleaning and replace the O-rings as they smelled horrible!!)
I recently purchased a new Oceanus from Brian/August Industries and I also bought one of these new/old stock separators to add to my Filter stack the same way, gutted and filled with 13x. (I did have to do a good cleaning and replace the O-rings as they smelled horrible!!)
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Graeme Tolton
Contributor
First off, davey didnt go out of business. http://www.daveycompressor.com/
Second, there are enough of these floating around that parts is no big deal. There are places to get new and used parts.
These units are an inexpensive way of getting into a high volume compressor.
Lastly, all of this is irrelavent when discussing one component of the system that has no moving parts and the only real failure point/ maintenance item is the o-rings which are readily available from any hydraulic supply store!!
T
frogman62
Contributor
I agree with Graeme, These are rock solid and lots of them are available. I sent one that was in very bad shape -inside pitted, but not deep, to have it destructed. At 26,000PSI it finally came apart. No need to worry about them.
Jim Shelden
Jim Shelden
Fatigue Stress
A large crack in metal starts much like a crack in your windshield. First you get a small star from a rock, and then on a cold day when you switch on your heater and stress on the glass is at its maximum, the teeny tiny crack can explode into one several inches long or more. Pitting is like the windshield star - it can be a teeny tiny crack waiting to form a much larger one. It may or may not – it’s a gamble. However, every time the metal experiences stress, fatigue can cause any of these tiny cracks to travel. Very slowly at first, but over time a critical point is reached where the crack will travel faster and faster just before failure.
This is why fatigue stress damage is so difficult to find or estimate visually, even with a proper hydro. The tiny crack that passed a hydro can grow later with more fatigue cycles and eventually fail. For example, Luxfer had issues back in the 70’s/80s with sustained load cracking in their cylinders (see pic), where a microscopic crack would travel without fatigue cycles (unusual) in aluminum 6351 tanks. Tanks would pass hydro and explode anyway, sometimes right after the test. The fact that frogman’s interfilter failed at 26,000psi simply means that the pitting had no cracks that were long enough at that point in its lifespan to propagate. It doesn’t tell us much information about the fatigue state of similar pitted pressure vessels, whether a tiny defect necessarily existed, or how many cycles it had left before it would fail.
The best way to prevent stress crack propagation is to inspect the material ultrasonically on a regular basis and catch the material defect before it grows to the point of failure. And in general, it is inadvisable to continue use of a pressure cylinder with any pitting.
A large crack in metal starts much like a crack in your windshield. First you get a small star from a rock, and then on a cold day when you switch on your heater and stress on the glass is at its maximum, the teeny tiny crack can explode into one several inches long or more. Pitting is like the windshield star - it can be a teeny tiny crack waiting to form a much larger one. It may or may not – it’s a gamble. However, every time the metal experiences stress, fatigue can cause any of these tiny cracks to travel. Very slowly at first, but over time a critical point is reached where the crack will travel faster and faster just before failure.
This is why fatigue stress damage is so difficult to find or estimate visually, even with a proper hydro. The tiny crack that passed a hydro can grow later with more fatigue cycles and eventually fail. For example, Luxfer had issues back in the 70’s/80s with sustained load cracking in their cylinders (see pic), where a microscopic crack would travel without fatigue cycles (unusual) in aluminum 6351 tanks. Tanks would pass hydro and explode anyway, sometimes right after the test. The fact that frogman’s interfilter failed at 26,000psi simply means that the pitting had no cracks that were long enough at that point in its lifespan to propagate. It doesn’t tell us much information about the fatigue state of similar pitted pressure vessels, whether a tiny defect necessarily existed, or how many cycles it had left before it would fail.
The best way to prevent stress crack propagation is to inspect the material ultrasonically on a regular basis and catch the material defect before it grows to the point of failure. And in general, it is inadvisable to continue use of a pressure cylinder with any pitting.
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