On Thu, 27 Sep 2012 12:43:39 -0700, Paul Drahn
wrote:

Hi, all.
On Site Gas systems is proposing a nitrogen gas generating system for
our selective soldering machines. We are using tanks of medical grade
nitrogen right now.

The proposal replaces our existing air compressor with a Kaeser model
SX-5 AirCenter, 5HP, rotary screw compressor. A refrigerated air dryer
is part of the compressor. Our existing compressor is a 13 year old 4
cylinder Speedair single stage from Grainger. It is rather noisy, even
though I built a sound absorbing enclosure around it.

My questions are does anyone have any experience with the German made
compressor and what type of noise does the screw compressor make?

Any help is very much appreciated.

Paul Drahn, President
Jodeco, Inc.

Screw compressors are usually a lot quieter inherently - because they
soundproof them on purpose, or they'd make a whine/moan. Instead of
pistons and cylinders and the chugging... it's basically a GMC 6-71
style Roots Blower driven by an electric motor.

It is better for your bottom line, too - Screw Compressors are usually
operated in Unloader mode, they run all day and just kick the
compressor in and out as needed. (Switch it off Unloader and into
Start-Stop when you go home for the night and over the weekend. Or
just Off and let the Speedaire catch it.)

On a 5-HP the main benefit is longer motor life without all the
stopping and starting that burns the windings - but on the bigger 10 -
25 - 50 HP ones where your factory is on a Demand {Power Meter system,
eliminating all the Start Surges during the day and cutting the Demand
Factor adder on your power bill is a huge benefit.

Though I would have them install the new compressor and the N2
Generation System in the same corner as the Speedaire with room
deliberately left around it, so you can build another sound cover if
it's too noisy for you. Or better yet, wall off that whole corner of
the factory into a separate little room - Which is better, because you
can ventilate that room to the outside and keep the equipment a lot
cooler.

And KEEP the other compressor, now you have a backup. For best
results, hook up a few valves so either machine can feed both the N2
Generators and the Shop Air lines to the workbenches, and you can keep
going if one fails.

(Though you may have to tell your people to ration air if the
Speedaire can't keep up...)

Leave room around the compressors and N2 Generators and it's receiver
tank, and rig the piping and wiring so you can get one piece of the
puzzle out and replace it with the other still running. You don't
want to pay me overtime for coming in after hours, and you don't want
your people sitting idle while I work on the air system.

You rig the Air Dryers and Filters with a three-valve Bypass so they
can be serviced or swapped with the air system hot too, same reason.

The N2 Generator people might not like you feeding their machine with
a piston compressor, but it's for emergencies. If you put a
refrigerated dryer and a oil-coalescing filter on the output line from
the Speedaire too, they really can't say much.

-- Bruce --