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Re: NEON- Re: oxygen in neon fires, Neon-l server was down

John Anderson wrote:

> Dirk said:
> 
> > OP. You only need a small amount of oxygen for stabilising the flame and
> > for making the focus of the flame hotter so that the flame is cooler to
> > the outsides. 
> 
> I find this the biggest advantage of adding oxygen.  I've added small
> amounts to both a cannon fire and a BMT-7 ("splicing") fire.  With such,
> the flame is quieter, smoother, hotter, and there's significantly less
> "splash" -- I can have my fingers almost 1" away without getting burned.
> Very nice indeed.
> 
> But it's too costly for me with the above burners.  I have a small tank
> hooked up to a HOKE torch for tubulating, fixing holes, and general
> cosmetic retouching.  I've wondered how good those oxygen generators
> are.  My understanding is that the output is about 80% pure, and they
> work by forcing air thru a filter of sorts that lets mostly O2 by.  This
> might make it practical, but I bet they're expensive?

Reply from dirk:
Dear JOhn, (now I am doing the JO and you signed with Jo)
All the Italian neonshops I visited are using a so called oxybox (they
are made in Italy) and the output is 96% pure (+/- 6 %, but what's the
deal) They produce 1000 liter of oxygen by using 2 kW, so for our
country we have 1000 liter oxygen for the price of fl: 0.40 (about 25
dollarcents)
Calculating with that you can see that using an oxybox is at least 15
times cheaper than buying oxygen from a supplier in a cylinder. (I
compared these number with the price we must pay for a cylinder, I don't
know the what you must pay for a cylinder)
The needed so called screw-compressor for compressing atmospherical air
to at least 7 bar is very silent. The air is buffered in a 250 liter
tank and from this tank the compressed air is lead trough the oxybox to
a seperate tank which is filled with the oxygen.
You can use the compressed air from the tank for your burners as well.
If you mount decent reduction valves, the flame will be as stable as
using an air blower. That type of compressor is oil-free with a big
capacity. The capacity of a two man workshop is about a volume of 175
liters a minute for having enough compressed air and oxygen. It is a
very common and widely used compressor capacity here in the Netherlands.
The smallest unit they produce have dimensions of 61x30x45 cm (2x1x1.5
feet) the weight is 25 kg (55 US pounds) with an inbuild 400 watt
compressor and is producing the equivelant of 0.7 cylinders (200 bar 5
feet long) a day. This is a portable hand-held unit. The units I saw in
Italy were all bigger units as these shop all had 4 or 5 benders working
in the shop, and they all worked with oxygen bench- and handtorches.
I have comprehensive documentation about these generators, so if you
want to have one, come back to me.
> 
> And a question for Dirk:  why would one NOT use "blowers" for neon, but
> compressors instead?  You say only 1 shop in Holland is using such.
> Blowers (and I'm thinking regenerative-type here) are quiet, oil-free,
> non-pulsing (no buffer tank needed), and very reliable (1 moving,
> non-contact part).  There was a shop here (until they burned down a few
> months ago) using a giant compressor as the air supply.  Seemed
> wasteful:  a 5 horse motor and it just barely did the job.
> 
>        -John
John, the blowers I saw here (and I don't mean the reefers) were noisy,
low capacity and they are on all day. They are consuming electricity
even when I don't need air at that moment. We are sons of Calvin you
know, we think that we are spilling energy using a blower like that. For
that reason we always have a buffertank with several different pressure
adjustments. One for the bench burner at 4 bar and onother one 2.5 bar
for the handtorches. (all added with half a bar overpressure of oxygen
as well) The lifetime of a compressor like that is over 20 years, so
what's the deal? My compressor ( a rather small one) is doing 250 liters
a minute of air, buffered in a 100 liter tank at 10 bar (so 1000 liter)
and this unit has enough capacity to let operate 3 (O2) burners
properly. Even then the duty cycle of the 2 kW motor is only 50%. (70%
when they all do 18 mm tubing) I used that compressor during sign Europe
in Dusseldorf Germany when the air supply from the organisation of the
exibition failed for several hours. (same exibition I met our friend
Marcus in person for the first time) There were 2 cross fires, 2
European type bench burners and 1 handtorche installed and the duty
cycle of the 2 kW motor was about 85%. We always install our compressor
as well using it for buffering the received air from the organisation
and as a spare part if something happens with the air supply. I agree
that a 5 horse motor is a waste, but I don't think we can blame the
motor or the power of the motor for that. When the cylinder or screw
(whatever the pricipel is) or the valves are to old and therefore
leaking, in a way we can compare with a carmotor when the compression
above the cylinder is nearly as high as the carter-compression, don't
blame the motor. That phenomenom we call maintenance. When the
air-leak-away is too big even a 10 horse motor will give the same bad
endresult. Two years ago the shool where our bending night course is
given had to buy a new compressor. The sucker worked for over 20 years
fine and was well maintained, but we still had to buy a new one as ATLAS
COPCO (do you know that company? one of the biggest here in Europe
selling air compressors) don't stock spare-parts from machines who were
developed for over 25 years ago. Now we have a compressor with a 3 kW
motor and it can charge 12 bench burners easy with a duty cycle of less
then 50%.
That is what we call a GREEN (clour of the environment here in Europe)
compressor, saving energy.
Best from dirk a. boonstra
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