Never have tried this, but there's nothing in my Aero Engineering background
that gives me any reason to think this wouldn't work. Two ways to view the
problem. First, the problem is equivalent to adding another carburetor on your
engine to give more air flow (we all know how that works). Second, the problem
is equivalent to two people blowing thorough two separate straws into a closed
tank (or two water hoses filling up a bucket); you fill the tank twice as fast.
Of course you won't get higher pressure, but you will get higher mass flow.
Perhaps not twice as much (due to frictional losses, etc.) but real close. Oh,
just to ensure proper mixing, I would pipe air into a plenum or manifold,
rather than just bringing pipes together in a Y (plenum would also reduce
shocks back towards one compressor when the other cuts in, etc.).
As a further point to further confuse the issue, what this scheme is doing is
putting two compressors in parallel in order to up the mass flow. In contrast,
a standard two-stage compressor is essentially two compressors in series, a
scheme which increases mass flow AND pressure. I'm sure there are electrical
analogies to both these "circuits".
I've been thinking about this, since I have one good 2 HP already. I
don't see why you could not simply create (out of iron or copper pipe) a
manifold that has an inlet from each compressor and an outlet (with a
regulator) for your sandblaster or whatever. You could install a shutoff
valve on one compressor so you used just one for small jobs, and crank
both up when sandblasting.
Can anyone think why this would not work?
Ray Gibbons Dept. of Molecular Physiology & Biophysics
Univ. of Vermont College of Medicine, Burlington, VT
firstname.lastname@example.org (802) 656-8910