"greg boyd" wrote:
I know this is way off topic , but YES a high pressure gas bottle will
project itself about 3 to 400 YARDS . The way that we emptied old military
bottles was to set them up on a ramp , then knock off the valves with a
sledge hammer . Made for quick work , got them empty , and more
importantly
, was a hell of a lot of fun.

I stand corrected. What size bottles were those, and what was the internal
pressure?

Regardless, the air tanks normally used with an air-compressor are designed
differently than high pressure gas tanks (the valve is mounted in the center
of the horizontal surface, rather than at the end), and the "missle-like"
characteristics are considerably reduced.

Moreover, it is unlikely that a person using compressed air to drive a
bladder press would have the tank sitting on a ramp, with the valve stem
oriented downward. The inertia of the floor (whether wood frame or concrete)
would create a resistance, and it would be the valve that would go sailing,
not the tank --- if the valve somehow broke.

I also hope that the home winemaker wouldn't be striking the valve with a
sledge hammer, and wonder if this could even be accomplished since such
tanks (are now required by law to) have a heavy metal guard plate
surrounding the valve.

Remember, compressed air (with storage tanks) is routinely used for
painting, in workshops, and in automotive garages, all over the world. If
the danger described was a realistic concern, we should be equally worried
about the safety of craftsmen and passersby. With a 300-400 yard range, no
one on the planet would be safe.

Negodki wrote:

Moreover, it is unlikely that a person using compressed air to drive a
bladder press would have the tank sitting on a ramp, with the valve stem
oriented downward. The inertia of the floor (whether wood frame or concrete)
would create a resistance, and it would be the valve that would go sailing,
not the tank --- if the valve somehow broke.


I read of a case once where a compressed gas delivery was being made
from a truck with a lift gate. Upon lowering the lift, a tank fell over
& hit its valve on the truck. It took off like a rocket, across the
loading bay, through the entire warehouse and struck some heavy
equipment at the far wall. At that point it was deflected upwards, 'til
it hit the roof trusses, and, spent at last, fell to the floor. Nobody
hurt, but a lot of rubbery knees.

I imagine the valve went toward the truck, but more importantly, all of
the contents spewing out under pressure represented reaction mass, which
likewise headed truckward, while the tank headed warehouse-ward, under
the influence of Newton's Third Law, AKA Action & Reaction. Again, not
the result that one would first expect.

Remember, compressed air (with storage tanks) is routinely used for
painting, in workshops, and in automotive garages, all over the world. If
the danger described was a realistic concern, we should be equally worried
about the safety of craftsmen and passersby. With a 300-400 yard range, no
one on the planet would be safe.

And that is exactly what makes this sort of thing so dangerous.... that
people routinely underestimate the danger and fail to take adequate
precautions. Ask an industrial insurance underwriter, or an industrial
safety officer. The replies will be chilling.

BTW, my brand spanking new, 40 liter bladder press (from Italy, by way
of Texas) came with all sorts of warnings NOT to use air. It even has a
multilingual warning to purge all air from the bladder upon first
filling. This last warning is cast into the iron of the cover plate, so
I guess they think it's important.

Really, we're not pulling your leg on this.

Luck, Mike MTM

"Negodki" wrote in message
...
I KNOW that some wineries do [wash there fruit], and others don't.

I've never heard of a winery washing its fruit. Care to name names?

Tom S

"Negodki" wrote in message
...
"Brian Lundeen" wrote:
Which is where my fear lies. I have little fear of a CO2 tank exploding,
but
I do fear the valve breaking off and turning that cylinder into a very
destructive rocket.

What are the probabilities of this happening? I can't recall reading of
an
errant CO2 (or other gas tank) shooting through the skies, and assume that
it is an extremely rare incidence, far less frequent than burst hoses.

I've heard of it happening, but not with a CO2 cylinder. The static
pressure isn't high enough. (At 70°F a CO2 cylinder is at 825 psi) A fully
charged Oxygen, Argon or Nitrogen cylinder could take off like a rocket
though.

The pressurized tanks used for oxy-acetylene welding are fairly heavy, as
are propane tanks. I doubt they would move far with a broken valve.

Propane tanks present more of a fire/explosion hazard in the event of a
valve assembly rupture.

An Oxygen [e.g.] tank is a different matter. If the neck snaps off, the
force that tank will move with is proportional to the area of the orifice
multiplied by the gas pressure. Even if the area is only ¼ of a square
inch, a tank at 2200 psi would have 550 pounds of force pushing it around.
I wouldn't want to be in the way of that!

If it
broke off, the valve itself might turn into a missile, which is why there
is
a heavy duty metal guard to prevent the valve from being bumped into.

I assume you're referring to the metal cap on a high pressure cylinder. You
have to remove that cap to put the cylinder into service. It's there only
to protect the valve assembly from damage, so you don't have a hundred pound
tank go shooting off like a missile when the valve snaps off in an accident.

I
suspect CO2 tanks are similarly constructed.

They aren't.

Manufacturers of bladder presses specify that water OR compressed air may
be
used. They caution that a pressure regulator must be used with compressed
air (and theoretically with water, if your local supply was more than 30
psi, which it is in some locals). In today's litigious society, if there
was
a tangible (or even remote) danger of the tank (or valve) exploding, I
suspect the instructions for the press would come with the following
disclaimer: "WARNING! DO NOT USE COMPRESSED AIR TO POWER THIS
APPARATUS!..."
followed by a lengthy dissertation of the possible results of such action.

The fact that there is no such warning, indicates to me that there is no
substantial probability with that which concerns you.

False. Most of the bladder presses are made in Italy. Do you _really_
think you could successfully sue the Italians for product liability in the
event of an accident? Good luck! :^/

Tom S

I always thought that the reason that liquids were used was the
compresssed much less then air. I.E. you lose more volume as you
compress air then you lose by compressing liquids.

but it is an interesting idea on the conversion, but i still see the
problem stated above able to play out here, the amount of pressure to
operate the press must be a lot higher then water.

"Ray" wrote in
m:


"Jim" wrote in message
...
I have adapted my bladder press to work on compressed air no leaking
water and if the bladder brakes I will not lose my must. I use a
small compressor with a valve in the line to shut of the compressor
at 25psi.

Yes but compressed air is far, far, far, far more dangerous.
Compressed gas blows out it throws things. Compressed liquid blows
out and it spits. That is why hydraulic systems always use liquid
rather than gas. This probably will not change your mind but just to
let others know -- this is not a good idea.

Ray

like most people here have said, there is some hazard, but look at what
the valves went through to get them to that point. A little care with
this equipment is required, but they are not however ultra sensative. I
have hauled a blow torch around in my trucks before. Me and the trucks
both survived, and its important to note because i'm a farmer, so the
truck and the tank were not always on the nice roads that you see all
the time.

But like i said, some caution is good, but leave paranoia at the door,
it will cause you lots of problems. The tanks can take some abuse, but
its still best to minimize it.

good luck and happy winemaking

Quakeholio

"Brian Lundeen" wrote in
:


"MikeMTM" wrote in message
...
This jives with what I
know about compressed gas: it's amazingly dangerous.

I'm going to stick with water to run my press. If it ever ruptures, I
just have to have a plan in mind to limit the dilution effects as much
as possible.

Of course, that doesn't help me on my brewing side. I have a 20 pound
CO2 tank in my basement for my keg fridge. I don't worry about it too
much, just sitting there. It's in a position where it is unlikely to
get knocked over.

But when it comes time to exchange it, that's gonna be one nervous
drive, expecially coming back with the full one. ;-)

Brian

"quakeholio" wrote in message
. 77.202...
I always thought that the reason that liquids were used was the
compresssed much less then air. I.E. you lose more volume as you
compress air then you lose by compressing liquids.

but it is an interesting idea on the conversion, but i still see the
problem stated above able to play out here, the amount of pressure to
operate the press must be a lot higher then water.

The grapes outside the bladder don't know whether there is 45 psi water or
45 psi air on the inside. Either "fluid" pressurizing the bladder works
just as well from that standpoint.

The difference is in the amount of _volume_ required between the two to
achieve the same pressure. According to Boyle's Law, it would take about
four times the volume of air to reach 45 psi as it would with water, because
the air is compressing as the pressure builds.

Tom S

Tom S ) wrote:

"Jim" wrote in message
.. .
Commercial wineries use large horizontal bladder presses
which are filled with air to 25psi. and to my knowledge no one has bin
injured by one.

That's not the same thing as a wood-slatted basket press. Tank presses are
made from stainless steel, and are surrounded by a second layer of steel
shrouding. They're _designed_ to run on compressed air. Basket presses are
not.

Tom S


I dunno. I have a couple of italian idropresses,and so far as I
know, they're designed to use compressed air. I run them to 4 bar
(64 psi) on a regular basis, so far without problem.

That said, I lie on the ground when adding pressure, so that if it
blows, it blows OVER my head, rather than through it. :-)

Dave
************************************************** **************************
Dave Breeden