Best place for remote extra tank

by Doug
(San Diego)

About extra storage tanks of the portable type:

it seems to help more for high demand, but short cycles, to place the additional tank near the tool. That way, the air resistance is reduced, and tank refills during rest periods. Think impact wrenches doing tire work.
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That's because typical portable compressor air tanks are small, meaning they have a good supply of air to the tool, but for a short period of time before their pressure is exhausted to line pressure.

Thanks for the good tip.

B.

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Intercooler - sort of

by Doug
(San Diego)

Many, if not most compressors use a ribbed pipe from the head to the receiver. It is clearly intended for cooling.

If I need one, what am I looking for?
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Hi Doug... for all of your kind contributions, I wish I had a simple answer.

While a ribbed line may offer some cooling, usually the run is so short that I would expect minimal cooling to take place. Therefore, I usually recommend the use of copper pipe, available from any plumbing store in a variety of diameters. Copper pipe is heat resistant, which is important as the air coming out of the pump is typically very hot.

If you wished to emulate the ribs, maybe use a longer copper pipe and shape it so that there is a longer run, with some gentle bends, before the pipe meets the tank.

Still, longer dwell time in the tank (or an add on tank) will greatly enhance de-watering as the air cools, and I always recommend a good quality air filter wherever the air is ultimately being used to remove the newly condensed water from the lines.

Hope this helps.

Bill

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Air tank won't fill?

by Jim
(Auburn, WA)

I have a 30 gal tank on my compressor that I run at 150 PSI.

I have a small 3 gal tank I want to use to fill tires in the field.

When I hook it up to my big tank with the compressor running the big tanks goes up to 150 PSI but the small one only goes to 35 PSI.

I am absolutely confused. Even if I leave them both hooked up together for a few minuets to equalize the small tank wont go any higher.

What am I missing Bill? I am even using one independent gauge to check both tanks.
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OK Jim, as I mentioned in your original post, the first thing I would look at is the reliability of the gauge. You say you have done that by using the same gauge to check the pressure in the main tank, and then in the air pig tank.

One shows 150 PSI (main tank) and the air pig tank shows 30 PSI. That is bizarre.

Please provide me specific details about how you have the two tanks connected. For example, are you using an air hose from the discharge coupler of the big tank and connecting it to an intake coupler on the small tank? Is there anything else in the line between the two?

Thanks,

Bill

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pressure relief valve on secondary tank

by Ralph Moran
(Waterloo,NY usa)

Bill
I have a 5 hp 25 gal. campbell air comp.

I connected it to a 75 gal. secondary tank.

I connected from primary compressor from the limit switch via pluming leaving the pressure relief valve in place, to the secondary 75 gal. tank which I also placed a pressure relief valve on, at the top of that tank.

My problem is the secondary 75 gal. tanks works fine for awhile, but about the second or third start up the pressure relief valve on 2nd tank goes off.

Do I need the relief valve on second tank? it is rated at 115-125#. The second tank is 300#rated capacity. Don't know what else to do or should i have a limit switch on second tank, but what good would that do?

Ralph Moran rmoran3@rochester.rr.com
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Might be best just to get a replacement PRV for the second tank that has a higher release point, Ralph.

I wouldn't want to have any pressure vessel that wasn't plumbed with a PRV.

If the first and second tanks are plumbed together as one, then the PRV on the first tank would work as a PRV on the second, as long as nothing would interfere with the flow between the tanks.

However, I would typically put the second air tank in series, with a check valve before the second tank so air from the compressor would flow into the primary tank, then past the check valve, into the secondary tank, and from it down to the air tools.

If the pressure switch ever failed with the compressor on, the compressor pump could fill the tanks with a dangerous level of air pressure, which is why you want all pressure vessels protected with their own PRV.

Bill

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Eliminating moisture - why wait til it gets into the tank?

by Mark
(Virginia)

Bill, I've been reading your excellent info on air compressors. I just bought my first one - a used Sanborn 60 gallon unit. 5 horse, 230v. Should be adequate for a homeowner who works on his own vehicles.

I was reading your advice on plumbing (thanks for the great explanation on why NOT to use PVC!) and got to thinking... (Dangerous, I know!)

Why not eliminate a bunch of moisture *before* it even gets into the tank? I'm thinking I could plumb from the cylinder head out to a cooler setup, and THEN into the tank, using a drop leg approach and automatic drain to get a lot of moisture out of the air before it even goes into the tank.

This would not eliminate drop legs & drains in permanent plumbing, of course, but I think it would reduce the amount of moisture that gets into the system.

What do you think?
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Your concept is valid, Mark.

The issue that is most difficult to deal with is that the longer the compressor runs, the hotter the air is going to be as it travels to the tank.

Aftercoolers deal with some of this, so, some higher end compressors do deal with this reality by cooling the air before it gets to the tank.

I prefer an energy efficient approach.

If the air travels from the compressor pump through a long path, there is lots of time for the air to cool, and drop out water in the run before it gets to the tank.

Good thinking on your part.

Bill

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