Ever see an air compressor like this?

[Leveleer]

Oil free opposed piston 2 stage 120V 14.67 CFM displacement
Pistons do not contact cylinder walls.
I built it just to see if I could.
I have no idea if there is a market for something like this.
The picture show a temporary test rig for evaluating various flow methods.
I accidentally let it pump up over 200 PSI which is well beyond the tank rating.

Frank

 

[kunkernator]

How quiet is it? You built it from scratch? I can't really get a good idea of how it works, the picture is way too large. Post up some more pictures.

 

[Leveleer]

Sorry about the large image, I reduced it.
Yes, I designed and built it all and it was fun for me. I made enough parts to build 4 compressors.
It's pretty quiet considering all the ports are wide open at the moment.
I'll post more pics and info soon.

Frank

 

[tatra]

Video with sound would be cool too.

 

[tatra]

New York air brake oil free compressor is in production.

 

[2oolhound]

It almost looks like it could have been mounted 90' so it doesn't stick out sideways so far.

Otherwise Nice Work!

 

[blazemaster83]

Nice work!

 

[Superbec]

well ... kind of hard to see another one like that since you designed and built it yourself and this is the first one

looks nice though, what's the amp draw on that huge motor in the back?
efficiency?
DA?

 

[Leveleer]

While attempting to determine the CFM output of my compressor, I made this video showing the precise time at each pressure.

The audio should give you a good idea of the sound level.
The motor current starts around 14 amps and climbs up to close to 20 at max pressure...

While testing I noticed that I could increase the CFM considerably by eliminating the tank check valve and replacing it with a gate valve I made.
I also made a aftercooler vessel that reduces the temperature considerably.

The first stage is actually double acting but in this configuration, I removed the 2nd reed valve plate and head.

Frank

 

[Leveleer]

I don't know if anyone noticed but the first stage pumps on the in stroke and the 2nd stage pumps on the out stroke.

Frank

 

[md21722]

Check valves are restrictive. Look into larger thread size. 3/4" NPT flows about 30 CFM.

 

[Leveleer]

I know check valves are restrictive. I actually bought one of these:

http://www.amazon.com/Control-Devices-Brass-Tank-Check/dp/B0081TIQJO/ref=cm_sw_em_r_t7_dp_d_g5htxb07KXAE3_tt
and it reduced my CFM by about 3 compared to my gate valve.

 

[Jarhead0408]

Very cool.

 

[Strouty]

That is cool, is it scalable to make more CFM?

 

[Leveleer]

It is definitely scalable. At one point I mounted a double acting first stage on both ends and the output was 60 cubic feet per minute. Only one problem. Much more horsepower required then my lowly 1.5HP motor could deliver at the time.

 

[Strouty]

Interesting, so I am guessing you either have a cool woman or you are single, looks like you are taking up the living room for this project.

With the design, can you figure out how much power you need to create a certain CFM or is it more of a trial and error method?

 

[Leveleer]

My wife is a lot more understanding since I moved my projects from our house to a separate facility.
Since I had the crazy idea to do this last July, it's been a lot of trial and error.
I use engineeringtoolbox.com quite a bit.

1st and 2nd stage reed valves
1st stage 4.5" bore 1" stroke 2nd stage 2.75" bore

Frank
1st stage inner displacement 14.67 CFM outer displacement 15.9 CFM

 

[wkndwarrior29]

That's very cool. Market interest would probably depend on cost.

 

[theoldwizard1]

Pistons do not contact cylinder walls.

Technically, oil lube piston compressor pistons do NOT touch the wall of the cylinder either. The rings do.

So how did you make the cylinder and pistons seal ?

 

[Strouty]

What I think would be your best option would be to sell them in kit form, especially if you can change simple portions to make more CFM. Then all you would have to do is make it so it would take specific size shafts and let them build the frame for the motor. If you get into making them as a unit, there may be some serious liability issues, even if you buy the tanks professionally made.

 

[firworks]

Whoah! engineeringtoolbox.com I had no idea about this site.

To the whiteboard!

 

[Leveleer]

Technically, oil lube piston compressor pistons do NOT touch the wall of the cylinder either. The rings do.

So how did you make the cylinder and pistons seal ?

THe only thing touching the cylinder wall is a elastomer energized teflon U-cup seal. Same goes for the inner piston rod seal.

Frank

 

[Strouty]

So you could also scale it down, maybe make them for 4x4 vehicles that want air. If you could make it small enough and still put out 10 CFM, that would probably be one heck of a tool for the trails.

Another thought would be for third world countries, remote locations, any place that bringing in a big compressor would be a PITA, this could offer the ability to carry the components in and assemble on site.

Being oil free, would you be able to do food service or dental type air?

 

[Strouty]

What are the overall dimensions, from he pictures it is kind of hard to judge. Also I am assuming that it can be mounted in any position?

What RPM range is it running? Maybe you could make it work on a DC motor?

 

[Leveleer]

So you could also scale it down, maybe make them for 4x4 vehicles that want air. If you could make it small enough and still put out 10 CFM, that would probably be one heck of a tool for the trails.

Another thought would be for third world countries, remote locations, any place that bringing in a big compressor would be a PITA, this could offer the ability to carry the components in and assemble on site.

Being oil free, would you be able to do food service or dental type air?

Thanks for the suggestions.
Since the crankcase is isolated from the compression section, it would be suitable for food service or dental I would think.
I could produce a version that would run on 12 VDC from a car battery and do 10 CFM. Probably would require about 800 watts.
Frank

 

[Leveleer]

What are the overall dimensions, from he pictures it is kind of hard to judge. Also I am assuming that it can be mounted in any position?

What RPM range is it running? Maybe you could make it work on a DC motor?

The compressor measures 15 inches from head to had as shown. About 18 inches in the other direction.

It's powered by a Leeson 2HP 1725RPM 56C ODP motor running on 115V.

It could be powered by anything capable of turning the shaft AFAIC.

Frank

 

[Strouty]

OK, so now the big question, what are we looking at for costs? Can you build it and create the a niche market so if it is expensive no one cares or can you have someone CNC the parts so it becomes a reasonably priced solution for people that have a junk pump, but a good tank and motor?

 

[Leveleer]

OK, so now the big question, what are we looking at for costs? Can you build it and create the a niche market so if it is expensive no one cares or can you have someone CNC the parts so it becomes a reasonably priced solution for people that have a junk pump, but a good tank and motor?

I do have a major advantage having made every single part myself on my little RoboDrill CNC mill including everything from the crankshaft to the reeds to the piston seals.
I retired over 12 years ago and am almost 70 so this is mostly a hobby.
My plan is to see how efficient I can make my design and then see how much more people are willing to pay for efficiency.
My little prototype is already outperforming all of my existing purchased compressors including my 5 horse Quincy.

If I never sell one it doesn't matter as I'll have them and be happy with them.
I have many other things in the pipeline.

Frank

 

[wingnut_1]

I like it Level! Looks like you have a little bit of time into this

 

[nine4gmc]

That's pretty nice, great job all around. I'm sure you know but be careful overfilling those tanks, I've seen horror pics here on GJ of ones that have exploded and taken walls out.

 

[Leveleer]

Thanks for all the kind helpful comments.

I wasn't planning on making reeds but the quotes I got were way too pricey so I decided to try making them myself.
Turns out it's really easy. I can cutout up to 10 at a time.

Frank

 

[theoldwizard1]

I could produce a version that would run on 12 VDC from a car battery and do 10 CFM. Probably would require about 800 watts.
Frank

A good market to go after !

THe only thing touching the cylinder wall is a elastomer energized teflon U-cup seal. Same goes for the inner piston rod seal.

My little prototype is already outperforming all of my existing purchased compressors including my 5 horse Quincy.

You need to do some durability test on those U-cup seals !

Compression is going to make heat. Heat is not good for elastomer. PTFE starts to break down above 600°F.

 

[Leveleer]

A good market to go after !





You need to do some durability test on those U-cup seals !

Compression is going to make heat. Heat is not good for elastomer. PTFE starts to break down above 600°F.

Good point.
Long ago I was involved in formulating teflon/PPS composites and some of these werre used as high temperature compressor seals.
Also I designed the compressor to be water cooled and my zero restriction flowpath reduces internal temperatures some.

 

[pcmeiners]

Low loss check valve, better then in-tank valves, (anything is better then an in-tank valve).....
http://www.kingstonvalves.com/23/Products/17/2/parts_details.aspx

 

[theoldwizard1]

Also I designed the compressor to be water cooled ...

Good idea, but that will make it a LOT larger and heavier and more complicated !!

 

[Leveleer]

Low loss check valve, better then in-tank valves, (anything is better then an in-tank valve).....
http://www.kingstonvalves.com/23/Products/17/2/parts_details.aspx

Thanks for the link. However, any loss is still a loss. I designed a lossless gate valve with built in actuator that I wil be using as soon as I get time to build it.
Of course my gate valve is more complicated and expensive then a check valve but performance is what matters to me.

Frank

 

[Leveleer]

Good idea, but that will make it a LOT larger and heavier and more complicated !!

That might be true if it was a conventional design but mine is far from that.

O.K. , it might be a little complicated.

Frank

 

[TheEquineFencer]

Let me give some more "air compressor " ideas to think about.

Here's a VERY popular compressor that's used with shallow gold dredging.

http://www.prolinemining.com/parts_accessories_T_80_compressor_parts.html

http://www.akmining.com/263-Twin-Pi...oductId=-431939&catalogid=-3389&shopby=-12953

A little more info copied from another website to give a little more insight:
The compressors that you use for diving need to put out some really clean air. A lot of the compressors you see in the shops put out contaminated air, dust, dirt and the air from some are contaminated with an oil residue as well as particles from wear. We used the T-80 on our small dredge [5"] and a 263 on the 8" dredge. The T-80 works from a filtered diaphragm, and the 263 even has a Teflon piston in it, so its super clean. The other thing you have to watch out for is the volume of air. We don't care how much pressure you have, it wont help if you don't have volume. Most of these things work at 40 to 45 PSI. Example: T-80 at1800 RPM gave me about 1.8 CFM or cubic feet per minute, this is good for one diver, two if neither of you breath very hard, on the other hand the 263 at 1450 RPM gives me about 6CFM and I have had three divers on it and it never failed on air supply for all three. Don't know what it takes to turn the 263. We didn't really care how much power it took because we had it mounted on a 1600 VW engine. The T-80 was on the five inch dredge which was powered be a 9 hp Honda w/P350 pump rated at around 450 gal.. per minute. The pump on my big dredge was a P1500V and would pump around 1400 gal. per min.. Had lots of power. Hope this helps some.

If you're looking a niche market, here it is.

 

[Leveleer]

We didn't really care how much power it took because we had it mounted on a 1600 VW engine.

If you're looking a niche market, here it is.

Thanks for the links.

Anyone happy with powering a compressor with a VW engine is not too concerned with efficiency.

Those concerned with energy efficiency are those I would like to have as customers.

Frank

 

[theoldwizard1]

I would love to see the piston and rings (before and after installation. Also the seal for the rod.

You must have a really large rod length:stroke ratio ! I have heard that this is one of the (not so secret) secrets for the single cylinder extreme mileage vehicles. Godd on all engine, but difficult to implement.