I have a couple questions about air receiver safety. I have a 20
gallon ASME carry tank (Grainger 4TK10). It has two 1/2" air outlets,
but I want to use it to honk an old fire horn which is not working
when I plumb from just one of the 1/2" outlets. I need more flow to
maintain proper blowing pressure at the horn. So my questions are
these:

1. Is there a known maximum safe discharge rate for a 20 gallon ASME
tank? The tank has a plate rating of MAWP 175 PSI @ 475 F. I need to
meter out half-second blasts at a rate of approximately 80 CFM. Is
this safe to do from a 20 gallon tank? What about from a pair of 20
gallon tanks?

2. Can I plumb the two 1/2" outlets into a common 3/4" or 1" tee? Is
there any safety reason not to?

3. Lastly, the tank has a 1-1/2" NPT inspection port that has a 1/4"
hole tapped in it for a guage. Can I replace this plug with a
1.5"-to-1" hex bushing and plumb right from there, or is this a no-no.

I want to get full flow to the horn, but I don't want to do anything
that is likely to cause the tank to lose integrity or fail
explosively/implosively. I've found lots of useful information about
maximum tank pressures, but I can't find anything on the web about
maximum discharge rates or air tank implosion.

Thanks,

Adam
adam at airraidsirens dot com

I don't think you have to worry about the tank.
Truck shops use a similar tank with a 1&1/4"+ outlet size line and a dump
valve.
They point the discharge tube at the rim / tire bead area ofa newly mounted
tire and 'dump' the contents of the tank in about a half second. The wave of
high pressure air blows the tire up far enough that it catches the bead so
the tire will stay mounted for the rest of the inflation process through the
valve stem.
What you are doing sounds tame by comparison.
Some more info is at:
http://www.uniquetruck.com/products/...ategory&catego
ryid=9&subcategoryid=10
Hope it helps....
Jeff



"adam smith" wrote in message
m...
I have a couple questions about air receiver safety. I have a 20
gallon ASME carry tank (Grainger 4TK10). It has two 1/2" air outlets,
but I want to use it to honk an old fire horn which is not working
when I plumb from just one of the 1/2" outlets. I need more flow to
maintain proper blowing pressure at the horn. So my questions are
these:

1. Is there a known maximum safe discharge rate for a 20 gallon ASME
tank? The tank has a plate rating of MAWP 175 PSI @ 475 F. I need to
meter out half-second blasts at a rate of approximately 80 CFM. Is
this safe to do from a 20 gallon tank? What about from a pair of 20
gallon tanks?

2. Can I plumb the two 1/2" outlets into a common 3/4" or 1" tee? Is
there any safety reason not to?

3. Lastly, the tank has a 1-1/2" NPT inspection port that has a 1/4"
hole tapped in it for a guage. Can I replace this plug with a
1.5"-to-1" hex bushing and plumb right from there, or is this a no-no.

I want to get full flow to the horn, but I don't want to do anything
that is likely to cause the tank to lose integrity or fail
explosively/implosively. I've found lots of useful information about
maximum tank pressures, but I can't find anything on the web about
maximum discharge rates or air tank implosion.

Thanks,

Adam
adam at airraidsirens dot com

I don't think you have to worry about the tank.
Truck shops use a similar tank with a 1&1/4"+ outlet size line and a dump
valve.
They point the discharge tube at the rim / tire bead area ofa newly mounted
tire and 'dump' the contents of the tank in about a half second.

What you are doing sounds tame by comparison.

Indeed! Thank you for the reference. It's particularly interesting to
see that some of those carry tanks they're selling for that purpose are
aluminum to boot. This is reassuring.

I should have noted too that what I called my "carry tank" is better
called "portable". It's 50 pounds and ASME rated, the same tank Campbell
Hausfeld uses on their portable contractor compressors, not one of those
non-code tire inflator cans they sell at hardware stores.

Thanks,

Adam
adam ATsymbol airraidsirens DOT com

adam smith wrote:

I have a couple questions about air receiver safety. I have a 20
gallon ASME carry tank (Grainger 4TK10). It has two 1/2" air outlets,
but I want to use it to honk an old fire horn which is not working
when I plumb from just one of the 1/2" outlets. I need more flow to
maintain proper blowing pressure at the horn. So my questions are
these:

1. Is there a known maximum safe discharge rate for a 20 gallon ASME
tank? The tank has a plate rating of MAWP 175 PSI @ 475 F. I need to
meter out half-second blasts at a rate of approximately 80 CFM. Is
this safe to do from a 20 gallon tank? What about from a pair of 20
gallon tanks?

2. Can I plumb the two 1/2" outlets into a common 3/4" or 1" tee? Is
there any safety reason not to?

3. Lastly, the tank has a 1-1/2" NPT inspection port that has a 1/4"
hole tapped in it for a guage. Can I replace this plug with a
1.5"-to-1" hex bushing and plumb right from there, or is this a no-no.

I want to get full flow to the horn, but I don't want to do anything
that is likely to cause the tank to lose integrity or fail
explosively/implosively. I've found lots of useful information about
maximum tank pressures, but I can't find anything on the web about
maximum discharge rates or air tank implosion.

Thanks,

Adam
adam at airraidsirens dot com
letting air out of an air tank that has pressure will not make it
implode.. the only way it will implode is if there is a vacuum inside
the tank and the pressure outside the tank is higher than the vacuum..

Adam wrote in message ...
I don't think you have to worry about the tank.
Truck shops use a similar tank with a 1&1/4"+ outlet size line and a dump
valve.
They point the discharge tube at the rim / tire bead area ofa newly mounted
tire and 'dump' the contents of the tank in about a half second.

What you are doing sounds tame by comparison.

Indeed! Thank you for the reference. It's particularly interesting to
see that some of those carry tanks they're selling for that purpose are
aluminum to boot. This is reassuring.

I should have noted too that what I called my "carry tank" is better
called "portable". It's 50 pounds and ASME rated, the same tank Campbell
Hausfeld uses on their portable contractor compressors, not one of those
non-code tire inflator cans they sell at hardware stores.

I wonder what they use in those potato and pumpkin cannons?

I wonder what they use in those potato and pumpkin cannons?

The only one I ever saw used a 2" iron pipe with a cap on the end tapped
for a spark plug. Some butane was sprayed into the pipe from a lighter
refill canister, which mixed with the air of course, then the potato was
jammed in almost to the bottom to compress the mix. Then, a 9V battery
was applied to an ignition coil hooked to the spark plug. Next time I
saw the potato it was hundreds of feet in the air. I didn't do this
myself BTW, and I didn't want to be anywere near it when it was
fired--I'm not crazy. I saw this experiment at an
all-engineering-students frat house back in my college days.

-Adam
adam at airraidsirens dot com

adam smith wrote:

I have a couple questions about air receiver safety. I have a 20
gallon ASME carry tank (Grainger 4TK10). It has two 1/2" air outlets,
but I want to use it to honk an old fire horn which is not working
when I plumb from just one of the 1/2" outlets. I need more flow to
maintain proper blowing pressure at the horn. So my questions are
these:

1. Is there a known maximum safe discharge rate for a 20 gallon ASME
tank? The tank has a plate rating of MAWP 175 PSI @ 475 F. I need to
meter out half-second blasts at a rate of approximately 80 CFM. Is
this safe to do from a 20 gallon tank? What about from a pair of 20
gallon tanks?

A short 1/2" line with full-port fittings and valves will dump 80 CFM at an
insigificant pressure drop, just a few psi at 175 psi.

Backing up here for a moment, the 20 gal tank holds 33 standard cubic feet
of air at 175 psi. That's less than a single half-second blast. If it's
taking more than a half second to dump the tank thru a 1/2" port, there must
be a restriction somewhere.

Bob

In article ,
Adam Smith wrote:

I wonder what they use in those potato and pumpkin cannons?

The only one I ever saw used a 2" iron pipe with a cap on the end tapped
for a spark plug. Some butane was sprayed into the pipe from a lighter
refill canister, which mixed with the air of course, then the potato was
jammed in almost to the bottom to compress the mix. Then, a 9V battery
was applied to an ignition coil hooked to the spark plug. Next time I
saw the potato it was hundreds of feet in the air. I didn't do this
myself BTW, and I didn't want to be anywere near it when it was
fired--I'm not crazy. I saw this experiment at an
all-engineering-students frat house back in my college days.

Bah... You make it sound like all spud-guns are an accident waiting to
happen.

Well, they are... But mainly if you can't AIM.

Best one I ever encountered was made out of nothing but PVC pipe and a
flint sparker out of an old coleman lantern. Barrel was 1.5" pipe about
3 feet long, with a fiarly long taper cut on the inside edge of the
muzzle end to make a pretty decent "knife edge" for cutting out good
tight-fitting chunks of potato. The "breech" was made out of a 4x8 inch
"cleanout" section with a screw-in cover, and the barrel was threaded
into a 4-inch to 1.5 inch cover/cap that fit the cleanout tube. Punched
through the side of the breech was the sparker. Firing sequence: Unscrew
breech plug, spray a 5-7 second shot of rite-gard, final-net hairspray,
or similar into it and slap the cap on. Grab big tater, and punch down
onto muzzle end, cutting out a tight-fitting chunk of spud, punch
spud-slug down with a carefully measured chunk of broom handle for
compression, point, and spin the sparker. T-whunk! Tater gone bye-bye!
At a rather impressive rate of speed.

Worked OK for watermelon, too, although that was more of a "shotgun"
sort of ammo - The "slug" tended to break up on its way through the
barrel, and generally came out as a splatter of red pulp, closely
followed by the rind. Apples worked at least as well as potatoes.
Tomatoes didn't do so good... The one experiment with those was classed
a dismal failure - It didn't shoot the tomato - just turned it into
ketchup, with a sound not all that much unlike a half-liquid fart.

We messed with that thing on and off for the better part of a year
before one of the crew mis-aimed just enough to send the slug over the
fence to shatter against the neighbor's house - only about 10 inches to
the left of his 6x10 sliding glass door. We decided that things could be
a bit "messy" if we kept using that area asa target, and wisely moved
along to other pursuits. The guy's intended target was the fence itself,
but he aimed just a touch high, it seems. I was able to watch the
spud-slug miss the top of the fence by MAYBE 2 inches. The THWAP! as the
spud hit the vinyl siding was quite impressive. At least to us. Neighbor
was less than properly enthused. Can't really say I blame 'im...

--
Don Bruder - --- Preferred Email - SpamAssassinated.
Hate SPAM? See http://www.spamassassin.org for some seriously great info.
I will choose a path that's clear: I will choose Free Will! - N. Peart
Fly trap info pages: http://www.sonic.net/~dakidd/Horses/FlyTrap/index.html

"Don Bruder" wrote in message
news
In article ,
Adam Smith wrote:

I wonder what they use in those potato and pumpkin cannons?

The only one I ever saw used a 2" iron pipe with a cap on the end tapped
for a spark plug. Some butane was sprayed into the pipe from a lighter
refill canister, which mixed with the air of course, then the potato was
jammed in almost to the bottom to compress the mix. Then, a 9V battery
was applied to an ignition coil hooked to the spark plug. Next time I
saw the potato it was hundreds of feet in the air. I didn't do this
myself BTW, and I didn't want to be anywere near it when it was
fired--I'm not crazy. I saw this experiment at an
all-engineering-students frat house back in my college days.

Bah... You make it sound like all spud-guns are an accident waiting to
happen.

Well, they are... But mainly if you can't AIM.

Best one I ever encountered was made out of nothing but PVC pipe and a
flint sparker out of an old coleman lantern. Barrel was 1.5" pipe about
3 feet long, with a fiarly long taper cut on the inside edge of the
muzzle end to make a pretty decent "knife edge" for cutting out good
tight-fitting chunks of potato. The "breech" was made out of a 4x8 inch
"cleanout" section with a screw-in cover, and the barrel was threaded
into a 4-inch to 1.5 inch cover/cap that fit the cleanout tube. Punched
through the side of the breech was the sparker. Firing sequence: Unscrew
breech plug, spray a 5-7 second shot of rite-gard, final-net hairspray,
or similar into it and slap the cap on. Grab big tater, and punch down
onto muzzle end, cutting out a tight-fitting chunk of spud, punch
spud-slug down with a carefully measured chunk of broom handle for
compression, point, and spin the sparker. T-whunk! Tater gone bye-bye!
At a rather impressive rate of speed.


Ours had a 4 or 6 inch PVC barrel, a 1 1/2 inch busing inside, then a
cleanout plug at the end. Also used the flint igniter. Fuel was starting
fluid or pentane. The 4 incher would shoot a well packed snowball quite
nicely.

Always wanted to refine it for a more rapid fire and a larger barrel flame
at night...

snip
A short 1/2" line with full-port fittings and valves will dump 80 CFM at an
insigificant pressure drop, just a few psi at 175 psi.

Backing up here for a moment, the 20 gal tank holds 33 standard cubic feet
of air at 175 psi. That's less than a single half-second blast. If it's
taking more than a half second to dump the tank thru a 1/2" port, there must
be a restriction somewhere.

You forgot that the tank pressure is dropping (flow proportinal
to pressure)pressure at the port is dropping more rapidly than
the average pressure in the tank, and the very rapid cooling
going on. But it's still fast. Unless you are trying to drive a
spud gun, then it is not near fast enough.


Bob

--Talk about discharge rate, take a look at any decent sized
punkin gun! OBTW if'n anyone knows of where I can get my hands on an 8"
dump valve and a 200-gal tank for less than a fortune let me know! :-)

--
"Steamboat Ed" Haas : Another happy ****** living
Hacking the Trailing Edge! : in the Golden Age of Porno...
http://www.nmpproducts.com/intro.htm
---Decks a-wash in a sea of words---

steamer wrote in article
...
--Talk about discharge rate, take a look at any decent sized
punkin gun! OBTW if'n anyone knows of where I can get my hands on an 8"
dump valve and a 200-gal tank for less than a fortune let me know! :-)

--
"Steamboat Ed" Haas : Another happy ****** living
Hacking the Trailing Edge! : in the Golden Age of Porno...
http://www.nmpproducts.com/intro.htm
---Decks a-wash in a sea of words---




There's a government surplus auction at www.govliquidation.com that closes
on Jan. 5 that has some 8" valves. Guillotine and ball valves from the
look of them. Most of the stuff is at Norfolk, Va. Was browsing it last
night.

Garrett Fulton



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