pdp1@EARTHLINK.NET on fri 26 may 06
Hi Carl,
No one seems to have replied to your question..!
I think it mostly boils down to the RPM at which
the Air Pump turns... and will be effected also by
the sound of the ambient Air being pulled in
co-responingly close inspirations...the kind of
Check Valve that is used...
High RPM will make a lot more noise, from the
( typically un-muffled )
Air intake, from the total mechanical noise itself
of the whole, the
coupler-drive or whatever with integral
motor-pumps, the
valves
maybe somewhat and whatever else...the kind of
piston and crank-case
it is, The kind of Check Valve,
which will anticipate by design, high RPMs verses
low...all of it
combined.
One could try the experiment, which would WAY
increase the lifetime of an erstwhile high RPM
outfit, and reduce the noise way WAY down, by
finding a way to run it at say 400 RPM instead, at
liesure, for filling big tanks of reserve Air,
but this would be hard to do somewhat, since these
are usually proprietary direct drive or maybe
close coupled geared down drive to their
integral Motor...and would of course put out much
less air, much less CFM anyway, than their
intended
amount...and for the troubles it would take to do
this, one could more happily just get an older
quiet kind of Air Pump, a Motor, some Pullies and
Belts, a Tank, and combine them to suit one's
needs...
Larger Capacity lower RPM Air Pump Cylinders &
Pistons, will
compress
as much or more Air, for overall CFM @ a given
pressure, at a lower RPM...than the usual high RPM
ones.
This costs more to manufacture...and would be Cast
Iron generally rather than Die Cast components.
Too, no reason I can think of, why an interested
Manufacturer could not make a completely
exemplary, fine, quiet, durable, good looking
outfit useing Aluminum alloy or 'Lynite' or
kindred alloy Air Pump castings, Air Cooled,
sleeved with
fine grey-grain Cast Iron inserts, and Lynite
Piston(s)
even as Aeroplane or Motocycle and some Automobile
Engines have, or
had, back when they were in some Hay day...
And better Valves, better shaped egress for the
compressed Air to leave the Cylinder, intimate
Check Valves next to the Cylinder instead of them
being distal, and located where the Air line
enters the Tank...all of it, really, seems usually
to ask for some improvement.
Air is viscous, elastic, has inertia or momentum
( or resists acceleration at any rate, of whatever
kind, ) according to it's mass...and when
manipulated in this context, the understandings
which were all worked out very well by the 'teens
or 'twenties for Gasoline Engine's intake and
exhaust preformance ( if seldom applied in those
days, was known in thaory anyway), should have
been, or could be, applied to this kindred
concern.
Maybe they do? Or I mean someone is applying them?
I dunno, hard to keep up with
everything...but...not that I have seen anyway...
I would, do it that way, if I was in that
business...in a
Heart-beat...
Too, Radial designs, having three or five
Cylinders, used to be made ( if not to any great
extent) which would put out a lot of Air for each
single revolution of the Air Pump's Crank
Shaft...but, of course, this is easily several
times the expense to make or buy, and requires a
Motor of suitably larger Horse Power, than a
single or two Cylinder design...even if the result
is potentially very much more productive for any
given time interval of use. And, in theory, could
be made to be very quiet...serene even...
Lol...
Phil
lasveggy
----- Original Message -----
From: "Carl Finch"
> At 09:12 PM 5/21/2006, Stephani Stephenson
wrote:
>
> >The compressor is not as loud as others I have
heard.
> Which reminds me of my recently acquired
compressor and a question that's
> been puzzling me:
>
> Compressors are known to be pretty noisy,
generally, but what makes some SO
> much noisier than others?
>
> I'd owned a smallish Campbell-Hausfeld (5 gal.,
120v, 100 psi, oil-lubed)
> for some 25 years. It sounded like a freakin'
machine gun when
> running. I'd flee the garage after turning it
on while it reached
> pressure--or wear ear protection.
>
> Then a few months ago I had the good fortune
(Freecycle--gloat!) to come by
> a larger and older Sears unit (no model number
visible, but likewise 120v,
> 100 psi and oil-lubed). This one is probably 10
or 15 gallons and has two
> cylinders (though still single-stage).
>
> And it is MUCH quieter! No sharp edge to the
sound as with the smaller C-H
> compressor.
>
> So why is that? What makes some compressors so
much noisier than others?
>
> --Carl
> in Medford, Oregon
> feelin' a bit sheepish for giving my old C-H to
my son
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