high pressure air compressor 3500 psi

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hammermill
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high pressure air compressor 3500 psi

Post by hammermill »

Hello all,

I am looking for some guidance on construction of a 3500 psi air compressor.

I realize it will need to be done in 3 stages more than likely, and will not need very big pistons.

Questions are, at these pressures, are ball check valves a option?

I am not looking at a lot of volume, say 1 cubic foot a day.

Air does not need to be breathable.

I am also wondering about using sprial cut pistons rings to hold against that kind of pressure.

Lubrication suggestions??

I guess thats enough for a first post.

Thanks and hello
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mcostello
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Location: Lancaster, Ohio

Re: high pressure air compressor 3500 psi

Post by mcostello »

No advice, but most intriguing. Air powered log splitter?
randyc
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Re: high pressure air compressor 3500 psi

Post by randyc »

You may not get much of a response to your questions, for matters of safety. Suggest you try one of the mechanical engineering forums but even there the responses will be necessarily limited, restrained and filtered. In order for an engineer to provide a meaningful reply (which implies that he is partially assuming some moral if not legal responsibility) I'd imagine that you'd have to post a fairly detailed drawing with dimensions, material and processes (welding and so forth) clearly defined.

The "Practical Machinist" forum, however, includes a lot of people who are free with advice and opinions. Many of the members are qualified but advice is worth what you pay. Personally I would seek the advice of a LISCENSED "Professional Engineer". The term "profession engineer" is a legal one, not one that is granted by education or experience. The opinion of an engineer with these credentials is reliable to the extent that they have a legal obligation to provide you with safe advice - NOT opinion. You will, of course, have to pay for their assumption of responsibility, LOL.

Good luck,
Randy C
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GlennW
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Re: high pressure air compressor 3500 psi

Post by GlennW »

Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!
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mechanicalmagic
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Re: high pressure air compressor 3500 psi

Post by mechanicalmagic »

First off, I have never tried to build a 3500 psi compressor.
Second, pressures this high are dangerous, I assume you have the proper training. (I did, years ago.)

Very high pressure compressors often use a scheme where a large cylinder is used to compress the gas in a small cylinder. This has the advantage of higher "crankcase" pressures".

Yes, check valves are used at these pressures. The seat design must insure that there is no possibility of extruding the soft seal.

No thoughts on spiral piston rings.

If I had this task, I would round up:
2 cu ft High pressure cylinder
3500 psi Hydraulic pump /w tank
gauge & fittings
5 cu in volume.

Fill cylinder with air,
Pressurize cylinder to 3500 psi hydraulic fluid (bottom of cyl),
Fill 5 cu in volume with 3500 psi air off the top of cyl.
Bleed hydraulic fluid back to into tank.
Repeat as needed.

Please note, this can be a dangerous operation. Even air over oil compressors are lethal.

Dave J.

EDIT: If you are in Northern California, PM me. I may be able to help.
Every day I ask myself, "What's the most fun thing to do today."
9x48 BP clone, 12x36 lathe, TIG, MIG, Gas, 3 in 1 sheetmetal.
Jose Rivera
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Re: high pressure air compressor 3500 psi

Post by Jose Rivera »


Leave it to Glen !!!!! :D :D :D
There are no problems, only solutions.
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Retired journeyman machinist and 3D CAD mechanical designer - hobbyist - grandpa
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GlennW
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Re: high pressure air compressor 3500 psi

Post by GlennW »

I occasionally operated a single cylinder diesel powered high pressure compressor in the late 70's for a friend, but don't recall any details about the compressor section.

It made a Harley Davidson look sedate...
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!
JHenriksen
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Re: high pressure air compressor 3500 psi

Post by JHenriksen »

Haskell makes air powered intensifiers for both air and hydraulic apps. Our scuba place used a haskell pump for mixing gasses at high pressures. www.haskel.com
PixMan
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Re: high pressure air compressor 3500 psi

Post by PixMan »

Glenn Wegman wrote: It made a Harley Davidson look sedate...
I have a Kitchen Aide blender that can make a Harley Davidson look sedate. ;)
hammermill
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Re: high pressure air compressor 3500 psi

Post by hammermill »

thanks for the words of caution, i have written similar many times on other forums

i have a large air compressor unit for filling scba tanks and scuba tanks. however now that i am migrating to a home shop 10 hp 3 phase power is a bit much for a residental service.

and yes my machine is verymuch like a harley with a radical tune job and a bad muffler.
i would rather be next to a turbine that that beast.

i also have a hand pump for filling air rifle tanks, if you dont mind spending 45 minutes on a beast that looks a lot like a bike pump of old. it take about 85 to 90 pounds of force to complete each pump stroke so who needs a treadmill :lol:

my thoughts are a smaller pump that would be along the lines of the below mentioned link i just ran across http://www.automags.org/forums/forumdisplay.php?f=44


by way of experence i am a master eletrician, maintance mechanic working in several manf enviroments and part time pyrotech, i still have both eyes and 10 fingers and toes and plan on keeping it that way

the idea of using a liquid to compress air is interesting maybe using air with the oxygen take out
so you would be compressing nitrogen would be safer.???

thanks for the input fellows.
jim rozen
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Re: high pressure air compressor 3500 psi

Post by jim rozen »

If the volume requirements are truly that low, a bank of 1A nitrogen bottles would do the job.
You would need to fill sequentially from the bottles, don't manifold them all together. No
moving parts, no electricity required.....

Jim
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Bill_Cook
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Re: high pressure air compressor 3500 psi

Post by Bill_Cook »

Back in the late 60's my father picked up a small dive shop compressor with a worn 3rd (last) stage cylinder liner. It was bronze and a replacement was made of aluminum bronze, because he didn't have any phosphor bronze on hand. Worked just fine.

The piston was chrome plated, one quarter inch in diameter with no seal rings - just a good fit. Most of the head of the piston was a poppet check valve.

I don't remember what HP the electric motor was, but he did fit a 3 HP gas engine to it for use on the water.

BC
BC

If there was only one way to do each machining job, the smell of sulphurized cutting oil smoke would have fewer fond memories.
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