Compressed Air Dryer

I am quite awed by your compressor. I am highly surprised that such a big pump can be effectively driven by only a 7.5 HP motor, with seemingly big pulley.

i
Reply to
Ignoramus9179
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It was simple. As you can see there were two circuits going down each side of the "A" (called an "A" coil, for obvious reasons). I just bridged them in parallel and was done with it. Of course putting the coil directly after the compressor and before the tank would work better IMO, as suggested by Mr. Cook (the show off :^) ). You would still need a separator before the tank though. But this makes sense. It's easy, you'll figure it out.

John

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Reply to
John Flanagan

I take it you're an engineer :^)? Nice job. I'd thought of the same thing with a flow of water from the faucet to the drain. But never built it. Of course I did buy the parts though. Came up with the AC evaporator coil version with lower cost, no maintainence (sp?, too tired to look it up) later. The nice thing about faucet water is that it's significantly cooler than air during the hot summer months so you get a much lower dew point.

John

Please note that my return address is wrong due to the amount of junk email I get. So please respond to this message through the newsgroup.

Reply to
John Flanagan

I only rarely have trouble when it comes to winning who's got the biggest contests with it. :-)

I think I stated on the web site that the 7.5 is a little on the small side. I'm pushing it to the limit (though so far it's worked fine). I do have a 15hp to put on there but I've not had the free time to do the needed modifications (I'll have to rework the motor mount on the tank).

As for the pulley size keep in mind that it's a 1750 motor and the pulley on the compressor is rather large. I calculated the pulley size using formula's I found in Machinery Handbook which gave me estimates on CFM of the compressor and the like. There was also a table for HP per CFM so using the two I was able to calculate the proper rpm for the compressor to run with 7.5HP input and calculate the pulley needed for that rpm. When done and tested it turned out to be pretty close.

I've got a larger pulley on the 15HP motor which will speed up the compressor some. But I'm not going to go twice the speed that I'm running with the 7.5HP so that I'll have some head room (plus I don't want to wear the compressor out to fast).

Wayne Cook Shamrock, TX

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Reply to
Wayne Cook

Makes sense. Would be interesting to see how this project goes...

i
Reply to
Ignoramus23305

People occasionally comment that running a compressor more slowly is better. That it lasts longer. But I would think that its life is mostly a matter of the number of revolutions that it accumulates. And it will run only as many as needed to produce the air required. If you use 1000 cf per day, the compressor will only run the revolutions that produce 1000 cf, fast or slow.

Running it at twice the rpm will probably create higher cylinder temperatures while it's running, but the duty cycle will be 1/2 so the overall effect will be lessened. There may still be some net negative effect, but I wonder how much, really.

This argument only applies to a situation like Wayne's, where the compressor is of sufficient size that you don't have to wait for it to recover. Running a small compressor at twice the speed will not reduce the duty cycle by 1/2 if it means that you are using more air.

IMHO, Bob

Reply to
Bob Engelhardt

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