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cold propane

stephen on tue 7 sep 99

When I have had need to use my propane tank in cold weather the stuff
doesn't come out because it gets too chilled as it expands. Is there a safe
way to leave it out of my house but still warm it enough to work right? What
do you guys do?
Steve

Bruce Girrell on wed 8 sep 99

> When I have had need to use my propane tank in cold weather the stuff
> doesn't come out because it gets too chilled as it expands. Is
> there a safe
> way to leave it out of my house but still warm it enough to work
> right?

Water bath.

Place the tanks in water. If the water starts to freeze, just pour in more
water.

Water has a tremendous amount of heat available. It takes one calorie to
change one gram of water one degree Celsius. However... it takes a full 80
calories to change that same gram of water at 0 deg C to ice at 0 deg C.
That's a lot of available heat. To say it another way: If you had a bath of
water at 80 deg C (176 deg F) - that's _hot_ water - and you chilled it down
to 0 deg C, it would take exactly the same amount of energy to convert that
0 deg water to 0 deg ice.

So to be safe, you really don't need to warm the tank(s) at all - just keep
the water in the bath liquid and there will be plenty of heat available.

wschran@erols.com on wed 8 sep 99

During raku classes when we are nearing the end of a tank and it begins
to "freeze up", we put the tank in a container of water, having the
water come up about half way up the side of the tank. Should work in
cold weather also.
Bill

Dale A. Neese on wed 8 sep 99

I have started with a full tank in cold weather but sometimes even here in
Texas if the temperature gets below say 50 degrees it will start to slow
when gas is drawn off. I have heard of people covering the tank with a tarp
and blankets. Then run a hose from the exhaust of an automobile into the
tarp. Anyone?
I have found it better to make sure that my tank gets full sunshine in the
winter months. And then fire only in the sunny day-light hours.

Dale Tex

Pat Colyar on wed 8 sep 99

Steve, if your tank is small enough, put it in a big metal washtub, when
it starts icing up, bring 5-gallon buckets of hot water from the house
and pour them over the tank until it's sitting in warm water. Will work
at least temporarily. Good luck! Pat Colyar in Gold Bar, WA

Paul Lewing on wed 8 sep 99

stephen wrote:
>
> ----------------------------Original message----------------------------
> When I have had need to use my propane tank in cold weather the stuff
> doesn't come out because it gets too chilled as it expands. Is there a safe
> way to leave it out of my house but still warm it enough to work right? What
> do you guys do?
> Steve

Hi, Steve.
The best thing to do is to think ahead and always keep the tank
relatively full. You only get real problems when the tank is low. And
here's where having a bigger tank comes in handy.
I used to run hot water over my tank when it started to freeze up. That
will work for an hour or so, but then it's not enough to cope with the
freezing any more. But sometimes it can get those last cones dropped.
I had a friend who made a tent of canvas over his tank, and backed his
truck up to it. Then he piped the exhaust in under the tent to warm the
tank.
And I shared a studio with a real fire freak once. This was a guy who
would pull a lit burner out of the raku kiln (on a flexible hose) and
hold it up to his face to light a cigarette. This is with a six-foot
flame that would scorch the shed roof when he did this.
Anyway, when he raku-fired, he only had a 5-gallon tank, so it didn't
last long. When it would start to freeze up, he'd sit it in a wash tub
of hot water. That usually got him one more load. Then for one last
load, he'd take the burner out of the kiln and warm the tank with it!
You could really hear the pressure pick up! But it's not a method I'd
recommend. I always wanted him to wait while I stepped around the block
before he did this.
Paul Lewing, Seattle

Nikom Chimnok on wed 8 sep 99

Hello Steve and all,
Having once lived in the Yukon Territories, I've had some experience
with this problem. Up there you will find attached to every house a little
insulated shed, inside which the propane bottles are kept. Seems to me there
are two sources of heat in the shed--the ground, and what's lost through the
wall of the house. For cooking purposes, this is enough to keep the propane
from freezing up.
I myself had a big old tank, seems to me 250 gallons, inside an
insulated shed detached from the house. I was using it to heat the whole
house, tho, not merely to cook. At -60 F. it froze up. I got a battery
blanket--an electric heater designed to be wrapped around car batteries to
keep them operational when the temp is low--and stuck it inside the
insulation near the bottom of the tank. Plugged it in and problem solved, at
a cost of something like 80 or 120 watts per hour.
So as a generalized solution, I would say: build a well insulated
shed, and heat the shed with electricity. Is this safe? Not completely. If
you have a gas leak, the electric heater could conceivably cause an
explosion. Never heard of this happening, and I'm not the only one who ever
tried the electrical heating solution. I think that if you're clever enough
to do all the rest, you can also be clever enough to make sure there's no
gas leak. It's safest if you use a big tank and the gas company comes out
and fills it, instead of constantly hooking up and unhooking small tanks.
Come to think of it, a safer way would be to build a bigger shed and
use a light bulb to heat it. That way, the bulb would never be hot enough to
ignite gas, and the gas can't get to the glowing elements.

Good luck,
Nikom in Thailand, where it never gets cold, but the gas tanks still freeze up.

At 15:01 7/9/99 EDT, you wrote:
>----------------------------Original message----------------------------
>When I have had need to use my propane tank in cold weather the stuff
>doesn't come out because it gets too chilled as it expands. Is there a safe
>way to leave it out of my house but still warm it enough to work right? What
>do you guys do?
>Steve
>
>

John Rodgers on fri 10 sep 99

Pamela,
I've owned three VW buses ...currently driving one of the later ones with water
cooled engine. Only had to use the water-on-the-carburetor trick only once on my
aircooled "68" model. The carb pre-heater air hose broke. Carb iced up solid.

All were/are great for hauling pots, clay, wheels, pottery display units, 12 ft
ever owned. I went to one place for a load of clay and they were able to bring
the whole 1500 pound pallet load out on a forklift and set it on the floor of
the van right through the side door. Terrific machine!

John Rodgers
Driving a VW bus in New Mexico, currently loaded with several cases of cone 6
clay, two buckets of glaze, and a whole bunch of pots packed in boxes.

Pamala Browne wrote:

> ----------------------------Original message----------------------------
> All of this talk about "freezing up and using water has me reminescent(sp?)
> of my old VW bus.Used to pour water over the carb to "unfreeze" it in hot
> weather down in Texas.

> Oh god ,if this starts a thread on Vdubs I will
> never forgive myself!! < grin >

James Blossom on fri 10 sep 99

Hi Pamala.
This works because what you have is 'vapor lock'. The water cools the
manifold, gasoline vapor condenses, and off you go.
Mike Blossom
-----Original Message-----
From: Pamala Browne
To: CLAYART@LSV.UKY.EDU
Date: Thursday, September 09, 1999 9:20 AM
Subject: Re: cold propane

>----------------------------Original message----------------------------
>All of this talk about "freezing up and using water has me reminescent(sp?)
>of my old VW bus.Used to pour water over the carb to "unfreeze" it in hot
>weather down in Texas. Does anyone know WHY this works --is it the same
kind
>of thing as the propane? Oh god ,if this starts a thread on Vdubs I will
>never forgive myself!! < grin > This may not make it past the moderator
,but
>if it does I'll more information for this brain of mine. pamalab
>----- Original Message -----
>From: Paul Lewing
>To:
>Sent: Wednesday, September 08, 1999 10:11 AM
>Subject: Re: cold propane
>
>
>> ----------------------------Original message----------------------------
>> stephen wrote:
>> >
>> > ----------------------------Original
message----------------------------
>> > When I have had need to use my propane tank in cold weather the stuff
>> > doesn't come out because it gets too chilled as it expands. Is there a
>safe
>> > way to leave it out of my house but still warm it enough to work right?
>What
>> > do you guys do?
>> > Steve
>>
>> Hi, Steve.
>> The best thing to do is to think ahead and always keep the tank
>> relatively full. You only get real problems when the tank is low. And
>> here's where having a bigger tank comes in handy.
>> I used to run hot water over my tank when it started to freeze up. That
>> will work for an hour or so, but then it's not enough to cope with the
>> freezing any more. But sometimes it can get those last cones dropped.
>> I had a friend who made a tent of canvas over his tank, and backed his
>> truck up to it. Then he piped the exhaust in under the tent to warm the
>> tank.
>> And I shared a studio with a real fire freak once. This was a guy who
>> would pull a lit burner out of the raku kiln (on a flexible hose) and
>> hold it up to his face to light a cigarette. This is with a six-foot
>> flame that would scorch the shed roof when he did this.
>> Anyway, when he raku-fired, he only had a 5-gallon tank, so it didn't
>> last long. When it would start to freeze up, he'd sit it in a wash tub
>> of hot water. That usually got him one more load. Then for one last
>> load, he'd take the burner out of the kiln and warm the tank with it!
>> You could really hear the pressure pick up! But it's not a method I'd
>> recommend. I always wanted him to wait while I stepped around the block
>> before he did this.
>> Paul Lewing, Seattle

Stephen Mills on fri 10 sep 99

It cools the Carb down and stops the petrol from vaporising too early. A
friend of mine had an old Motor Bike that used to do that, he cured it
every time by peeing on the Carb!

Steve
Bath
UK

In message , Pamala Browne writes
>----------------------------Original message----------------------------
>All of this talk about "freezing up and using water has me reminescent(sp?)
>of my old VW bus.Used to pour water over the carb to "unfreeze" it in hot
>weather down in Texas. Does anyone know WHY this works --is it the same kind
>of thing as the propane? Oh god ,if this starts a thread on Vdubs I will
>never forgive myself!! < grin > This may not make it past the moderator ,but
>if it does I'll more information for this brain of mine. pamalab
>----- Original Message -----
>From: Paul Lewing
>To:
>Sent: Wednesday, September 08, 1999 10:11 AM
>Subject: Re: cold propane
>
>
>> ----------------------------Original message----------------------------
>> stephen wrote:
>> >
>> > ----------------------------Original message----------------------------
>> > When I have had need to use my propane tank in cold weather the stuff
>> > doesn't come out because it gets too chilled as it expands. Is there a
>safe
>> > way to leave it out of my house but still warm it enough to work right?
>What
>> > do you guys do?
>> > Steve
>>
>> Hi, Steve.
>> The best thing to do is to think ahead and always keep the tank
>> relatively full. You only get real problems when the tank is low. And
>> here's where having a bigger tank comes in handy.
>> I used to run hot water over my tank when it started to freeze up. That
>> will work for an hour or so, but then it's not enough to cope with the
>> freezing any more. But sometimes it can get those last cones dropped.
>> I had a friend who made a tent of canvas over his tank, and backed his
>> truck up to it. Then he piped the exhaust in under the tent to warm the
>> tank.
>> And I shared a studio with a real fire freak once. This was a guy who
>> would pull a lit burner out of the raku kiln (on a flexible hose) and
>> hold it up to his face to light a cigarette. This is with a six-foot
>> flame that would scorch the shed roof when he did this.
>> Anyway, when he raku-fired, he only had a 5-gallon tank, so it didn't
>> last long. When it would start to freeze up, he'd sit it in a wash tub
>> of hot water. That usually got him one more load. Then for one last
>> load, he'd take the burner out of the kiln and warm the tank with it!
>> You could really hear the pressure pick up! But it's not a method I'd
>> recommend. I always wanted him to wait while I stepped around the block
>> before he did this.
>> Paul Lewing, Seattle
>

--
Steve Mills
Bath
UK
home e-mail: stevemills@mudslinger.demon.co.uk
work e-mail: stevemills@bathpotters.demon.co.uk
own website: http://www.mudslinger.demon.co.uk
BPS website: http://www.bathpotters.demon.co.uk

Vicki Ferris on fri 10 sep 99

Steve,

When I Raku, I put the 5 gal. propane tank in a tub half full of water to
keep it from freezing up.

Vicki

Robert Santerre on thu 14 dec 00

Had essentially the same experience 2 weeks ago. The outside temp was hovering
between 35F and 30F. 500 gal tank was full. Firing our 40 cuft kiln. About 9
hours into the firing (~ 7PM) the kiln just shut off while I was standing there
staring at it - couldn't believe my eyes. I went out to the tank and the valve and
piping was heavily frosted up. I fiddled with the valve, knocked the tube with my
fist, said some BAD words, went back and started the kiln up again and it ran
another 3 hrs without incident.

When it stopped the pressure appeared to be holding at a steady 3 inches water
column and after restarting I maintained it at that pressure for the remainder of
the firing. I'm still a little puzzled by the incident, but my best guess is that
momentarily there must have been a pressure drop or a transient ice blockage of the
line that caused the flame sensor to automatically shut down the gas flow. I
fiddled around for maybe 15 minutes before trying to restart and that must have
been enough time to clear (melt) the blockage.

What ever? I'll try to pick a warmer day/night to do the next firing. The
electric blanket might not be a bad idea.

Bob

//////////////////////////////////////////////////////////////////////////////////////////////////////////////////

Tom Wirt/Betsy Price wrote:

> Hi Mark...
>
> Well here goes. We had a 1000 gal. tank freeze up firing before last,
> at night about minus 8 degrees outside. We had always figured the
> 1000 gallon gave us enough leeway, but have since found out, it's
> marginal at best under 10 degF.
>
> Here' s the poop. First, pressure is dependent on 3 things, surface
> area of the liquid gas, number of BTU's you are drawing and
> temperature of the gas. The lower the gas temperature, the lower the
> vapor pressure and thus less gas is available. So a tank that is 50%
> full is the best/largest surface area you can get.
>
> At zero DegF. nominal pressure is 23.5 lbs/Sq.In.
> At minus 10 DegF. pressure is 16.7 lbs/sqin
> At Minus 20 DegF 10.7
> At minus 40 degF 1.3 lbs
> At minus 43 degF. 0 pressure.
>
> The problem comes in when you start drawing gas off the tank, lowering
> the pressure in the tank and allowing the liquid gas to "boil" in the
> tank, to replace the lost pressure. That "boiling" lowers the
> temperature in the tank and thus the pressure. Now you're in a
> negative loop. With a 60 cu.ft. Kiln, I would assume you're pulling
> close to a million BTU/hour at peak temperature. The 500 gallon tank
> is probably way small for any outside temp under zero degF or minus
> 10.
>
> There are some secondary factors here involving valves which may
> freeze up but the key to keeping pressure is to keep the liquid, not
> the vapor in the top of the tank, as warm as you can. I'm also
> assuming your piping is at least a bit oversized. The first thing to
> do is try to get more surface area...say a bigger or second tank. Or,
> bury the tank in the ground.
>
> Heat can be added as you did, from a hose, but there are also
> magnetic crankcase heaters which will clomp onto the bottom of teh
> tank and add a bit of heat on a localized basis. 2 to 4 of them will
> do the trick. That's what the gas companies here recommend and most
> of the farmers use on their corn dryers. Even an electric blanket
> against the bottom of the tank can help. Do not, as you can guess,
> use any flame like a weed burner.
>
> There is a formula which takes surface area, outside temp and BTU draw
> and gives you available pressure. This is a cumulative deal. I'd
> suggest talking to a service guy at teh propane dealer. They should
> have all this available in reference books.
>
> The other thing we did was start the next firing in the very early
> morning so it would come down in mid-afternoon. Scrape any snow off
> the tank so sun can get to it and even lay a black tarp over the tank.
> We also wrapped the valve, regulator and exposed pipe with one of
> those electric pipe warming wires. Don't know if that's really doing
> anything for us, but it seemed to help.
>
> Hope this helps.
>
> Tom Wirt
> Clay Coyote Pottery
> Hutchinson MN
> claypot@hutchtel.net
> www.claycoyote.com
>
> ----- Original Message -----
> >Subject: Cold Propane
>
> Gotta question for you.
>
> I am not new to firing at all, but new to propane. I run my 60ft3
> kiln off of a 500 gallon tank and have twice now had the
> all-too-familiar pressure drop as the sun sets and the air temperature
> drops. I know that when it gets cold, you lose propane pressure. I
> also know that volume in the tank greatly affects pressure. The first
> time I had cones moving, the valve wide open and I was just plain
> losing temperature. I shut the kiln down. The second time I had more
> volume in the tank, but it still took the gas wide open to keep it
> going and we started to pour water on the frosted line to try to warm
> things up. We just made temperature either by luck or the garden
> hose, I don't know which.
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
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> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.

Dave Murphy on thu 14 dec 00

Tom:

I have a similar set up here in Canada. I have a 1000 gal tank and a 60 =
cu ft kiln. It is new so has not been fired in really cold temps yet =
but tomorrow I will be firing. The temps are supposed to be in the -3 C =
range so I do not expect to have any problems. I will watch with =
renewed interest at this aspect of the firing though. Thanks for the =

I think that this is quite interesting as I have noticed that when the =
tank is in the 50% range the reduction flame is vigorous and strong and =
too much on either side and it is more languid. Always thought I was =
just making it up.

Barbara Murphy
Waterloo County Pottery
Waterloo Ontario

Mark/El Rossier on thu 14 dec 00

Gotta question for you.

I am not new to firing at all, but new to propane. I run my 60ft3 kiln =
off of a 500 gallon tank and have twice now had the all-too-familiar =
pressure drop as the sun sets and the air temperature drops. I know =
that when it gets cold, you lose propane pressure. I also know that =
volume in the tank greatly affects pressure. The first time I had cones =
moving, the valve wide open and I was just plain losing temperature. I =
shut the kiln down. The second time I had more volume in the tank, but =
it still took the gas wide open to keep it going and we started to pour =
water on the frosted line to try to warm things up. We just made =
temperature either by luck or the garden hose, I don't know which.

My question is, is there any trick or gadget to help with this =
situation? I could always have a full tank when I fire, but that would =
mean the propane company would deliver to me once or twice a week! The =
last firing I started with 45% in the tank-- I thought I was safe. I am =
not interested in any solutions that are questionable in their safety,( =
for instance, I will not try to invert my 500 gallon tank or build a =
fire under it or any such silliness.) I vaguely remember Jeff Oestrich =
mentioning something he and Linda Christiansen use in such situations to =
warm things up. I sure would appreciate some advice.

I am not a regular clayart member, so I would appreciate responses being =
Thanks so much. =20

Mark Rossier
Boulder CO

Bruce Girrell on thu 14 dec 00

I have suggested some of the things that I do to help alleviate this
situation before, but I saw what I think is one of the best solutions when
Gail Nichols came to Traverse City last year and showed slides of her setup.
She has a dripper/soaker hose wrapped around her tanks. The tanks stay warm
enough and the water waste is minimized.

Can you get you hands on an OxyProbe to check your combustion efficiency?
You may be using more fuel than you need to.

Bruce "Hi, Gail!" Girrell

ThePottery@AOL.COM on thu 14 dec 00

The best advise is for you to exchange your 500 gal tank for a 1000 tank. If
not that hook another 500 gal together so that you draw from both at the same
time. Tracy

NLudd@AOL.COM on thu 14 dec 00

Only problem is, Gail, Mark's propane tank is in Rocky Mountain Colorado. At=
=20
this time of year a soaker system like you describe would freeze solid.=20

Ned (old studio buddy of Mark Rossier)

=97=97=97=97=97=97=97=97=97=97=97=97=97=97=97=97=97=97=97=97=97=97=97=97=97=
=97=97=97=97=97=97=97=97=97=97=97=97=97=97
In a message dated 12/14/00 2:27:10 PM, gailnichols@OPTUSNET.COM.AU writes:

>I use a garden 'soaker hose'.....a flat plastic hose with lots of very
>fine holes in it. Wrap it around the gas cylinders (one length of hose doe=
s
>2 cylinders), attach the other end to the water tap, then just turn on the
>water as you need it. Seems to solve the problem of freezing cylinders
>OK, without enormous amounts of water going everywhere.
>
>Gail Nichols
>Sydney, Australia
>gailnichols@optusnet.com.au

Tom Wirt/Betsy Price on thu 14 dec 00

Hi Mark...

Well here goes. We had a 1000 gal. tank freeze up firing before last,
at night about minus 8 degrees outside. We had always figured the
1000 gallon gave us enough leeway, but have since found out, it's
marginal at best under 10 degF.

Here' s the poop. First, pressure is dependent on 3 things, surface
area of the liquid gas, number of BTU's you are drawing and
temperature of the gas. The lower the gas temperature, the lower the
vapor pressure and thus less gas is available. So a tank that is 50%
full is the best/largest surface area you can get.

At zero DegF. nominal pressure is 23.5 lbs/Sq.In.
At minus 10 DegF. pressure is 16.7 lbs/sqin
At Minus 20 DegF 10.7
At minus 40 degF 1.3 lbs
At minus 43 degF. 0 pressure.

The problem comes in when you start drawing gas off the tank, lowering
the pressure in the tank and allowing the liquid gas to "boil" in the
tank, to replace the lost pressure. That "boiling" lowers the
temperature in the tank and thus the pressure. Now you're in a
negative loop. With a 60 cu.ft. Kiln, I would assume you're pulling
close to a million BTU/hour at peak temperature. The 500 gallon tank
is probably way small for any outside temp under zero degF or minus
10.

There are some secondary factors here involving valves which may
freeze up but the key to keeping pressure is to keep the liquid, not
the vapor in the top of the tank, as warm as you can. I'm also
assuming your piping is at least a bit oversized. The first thing to
do is try to get more surface area...say a bigger or second tank. Or,
bury the tank in the ground.

Heat can be added as you did, from a hose, but there are also
magnetic crankcase heaters which will clomp onto the bottom of teh
tank and add a bit of heat on a localized basis. 2 to 4 of them will
do the trick. That's what the gas companies here recommend and most
of the farmers use on their corn dryers. Even an electric blanket
against the bottom of the tank can help. Do not, as you can guess,
use any flame like a weed burner.

There is a formula which takes surface area, outside temp and BTU draw
and gives you available pressure. This is a cumulative deal. I'd
suggest talking to a service guy at teh propane dealer. They should
have all this available in reference books.

The other thing we did was start the next firing in the very early
morning so it would come down in mid-afternoon. Scrape any snow off
the tank so sun can get to it and even lay a black tarp over the tank.
We also wrapped the valve, regulator and exposed pipe with one of
those electric pipe warming wires. Don't know if that's really doing
anything for us, but it seemed to help.

Hope this helps.

Tom Wirt
Clay Coyote Pottery
Hutchinson MN
claypot@hutchtel.net
www.claycoyote.com

----- Original Message -----
>Subject: Cold Propane

Gotta question for you.

I am not new to firing at all, but new to propane. I run my 60ft3
kiln off of a 500 gallon tank and have twice now had the
all-too-familiar pressure drop as the sun sets and the air temperature
drops. I know that when it gets cold, you lose propane pressure. I
also know that volume in the tank greatly affects pressure. The first
time I had cones moving, the valve wide open and I was just plain
losing temperature. I shut the kiln down. The second time I had more
volume in the tank, but it still took the gas wide open to keep it
going and we started to pour water on the frosted line to try to warm
things up. We just made temperature either by luck or the garden
hose, I don't know which.

John Weber on fri 15 dec 00

The pressure in your tanks should have been adequate to supply propane for
your firing, eventhough I don't know if you are using natural draft burners
or power burners, but in either case your best bet is to contact Mark Ward at
Ward Burners and let him help you -- i.e., someone who knows what they are
doing. He would certainly want to know exactly what type of regulators your
are using and what kind of burners, also the size of the pipe and is this a
high or low pressure system.

mark boyd on fri 15 dec 00

if you have an outlet near, go buy some "heater tape" and wrap your tank
with a couple of turns. this is a product used most often to prevent pipe
freezing in cold climates, plugs into 110v outlet, very safe, and I think
you can even get ones that have thermostats on them. Local plumbing supply
can probably find them for you.
my guess is that it would temp the shell of the tank enough to help keep the
pressure high enough to do the trick.

Jim Larkin on fri 15 dec 00

Sometimes you get water in your tank and ice crystals will form in your
regulator ( the main regulator coming out of the tank) causing a blockage.
agent they use. It can help.
----- Original Message -----
From: Robert Santerre
To:
Sent: Thursday, December 14, 2000 8:43 PM
Subject: Re: Cold Propane

> Had essentially the same experience 2 weeks ago. The outside temp was
hovering
> between 35F and 30F. 500 gal tank was full. Firing our 40 cuft kiln.
> hours into the firing (~ 7PM) the kiln just shut off while I was standing
there
> staring at it - couldn't believe my eyes. I went out to the tank and the
valve and
> piping was heavily frosted up. I fiddled with the valve, knocked the tube
with my
> fist, said some BAD words, went back and started the kiln up again and it
ran
> another 3 hrs without incident.
>
> When it stopped the pressure appeared to be holding at a steady 3 inches
water
> column and after restarting I maintained it at that pressure for the
remainder of
> the firing. I'm still a little puzzled by the incident, but my best guess
is that
> momentarily there must have been a pressure drop or a transient ice
blockage of the
> line that caused the flame sensor to automatically shut down the gas flow.
I
> fiddled around for maybe 15 minutes before trying to restart and that must
have
> been enough time to clear (melt) the blockage.
>
> What ever? I'll try to pick a warmer day/night to do the next firing.
The
> electric blanket might not be a bad idea.
>
> Bob
>
>
////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////
>
> Tom Wirt/Betsy Price wrote:
>
> > Hi Mark...
> >
> > Well here goes. We had a 1000 gal. tank freeze up firing before last,
> > at night about minus 8 degrees outside. We had always figured the
> > 1000 gallon gave us enough leeway, but have since found out, it's
> > marginal at best under 10 degF.
> >
> > Here' s the poop. First, pressure is dependent on 3 things, surface
> > area of the liquid gas, number of BTU's you are drawing and
> > temperature of the gas. The lower the gas temperature, the lower the
> > vapor pressure and thus less gas is available. So a tank that is 50%
> > full is the best/largest surface area you can get.
> >
> > At zero DegF. nominal pressure is 23.5 lbs/Sq.In.
> > At minus 10 DegF. pressure is 16.7 lbs/sqin
> > At Minus 20 DegF 10.7
> > At minus 40 degF 1.3 lbs
> > At minus 43 degF. 0 pressure.
> >
> > The problem comes in when you start drawing gas off the tank, lowering
> > the pressure in the tank and allowing the liquid gas to "boil" in the
> > tank, to replace the lost pressure. That "boiling" lowers the
> > temperature in the tank and thus the pressure. Now you're in a
> > negative loop. With a 60 cu.ft. Kiln, I would assume you're pulling
> > close to a million BTU/hour at peak temperature. The 500 gallon tank
> > is probably way small for any outside temp under zero degF or minus
> > 10.
> >
> > There are some secondary factors here involving valves which may
> > freeze up but the key to keeping pressure is to keep the liquid, not
> > the vapor in the top of the tank, as warm as you can. I'm also
> > assuming your piping is at least a bit oversized. The first thing to
> > do is try to get more surface area...say a bigger or second tank. Or,
> > bury the tank in the ground.
> >
> > Heat can be added as you did, from a hose, but there are also
> > magnetic crankcase heaters which will clomp onto the bottom of teh
> > tank and add a bit of heat on a localized basis. 2 to 4 of them will
> > do the trick. That's what the gas companies here recommend and most
> > of the farmers use on their corn dryers. Even an electric blanket
> > against the bottom of the tank can help. Do not, as you can guess,
> > use any flame like a weed burner.
> >
> > There is a formula which takes surface area, outside temp and BTU draw
> > and gives you available pressure. This is a cumulative deal. I'd
> > suggest talking to a service guy at teh propane dealer. They should
> > have all this available in reference books.
> >
> > The other thing we did was start the next firing in the very early
> > morning so it would come down in mid-afternoon. Scrape any snow off
> > the tank so sun can get to it and even lay a black tarp over the tank.
> > We also wrapped the valve, regulator and exposed pipe with one of
> > those electric pipe warming wires. Don't know if that's really doing
> > anything for us, but it seemed to help.
> >
> > Hope this helps.
> >
> > Tom Wirt
> > Clay Coyote Pottery
> > Hutchinson MN
> > claypot@hutchtel.net
> > www.claycoyote.com
> >
> > ----- Original Message -----
> > >Subject: Cold Propane
> >
> > Gotta question for you.
> >
> > I am not new to firing at all, but new to propane. I run my 60ft3
> > kiln off of a 500 gallon tank and have twice now had the
> > all-too-familiar pressure drop as the sun sets and the air temperature
> > drops. I know that when it gets cold, you lose propane pressure. I
> > also know that volume in the tank greatly affects pressure. The first
> > time I had cones moving, the valve wide open and I was just plain
> > losing temperature. I shut the kiln down. The second time I had more
> > volume in the tank, but it still took the gas wide open to keep it
> > going and we started to pour water on the frosted line to try to warm
> > things up. We just made temperature either by luck or the garden
> > hose, I don't know which.
> >
> >
____________________________________________________________________________
__
> > Send postings to clayart@lsv.ceramics.org
> >
> > You may look at the archives for the list or change your subscription
> > settings from http://www.ceramics.org/clayart/
> >
> > Moderator of the list is Mel Jacobson who may be reached at
>
>
____________________________________________________________________________
__
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
>

Gail Nichols on fri 15 dec 00

I use a garden 'soaker hose'.....a flat plastic hose with lots of very fine
holes in it. Wrap it around the gas cylinders (one length of hose does 2
cylinders), attach the other end to the water tap, then just turn on the
water as you need it. Seems to solve the problem of freezing cylinders OK,
without enormous amounts of water going everywhere.

Gail Nichols
Sydney, Australia
gailnichols@optusnet.com.au

Nils Lou on fri 15 dec 00

Tom, why don't you use liquid withdrawal burners? Absolutely no freeze-up
problems at any temp. It is the solution for propane, especially across
the
northern tier of states. Used commonly in Japan where they generally use
expensive vaporizers, but are now gradually realizing that the self
vaporizing, liquid withdrawal burner is a lot cheaper.nils

Daniel Foscarini on fri 15 dec 00

Try looking for the tape at an RV supply store.

Dan

>From: mark boyd
>To: CLAYART@LSV.CERAMICS.ORG
>Subject: Re: Cold Propane
>Date: Fri, 15 Dec 2000 07:16:21 -0500
>
>if you have an outlet near, go buy some "heater tape" and wrap your tank
>with a couple of turns. this is a product used most often to prevent pipe
>freezing in cold climates, plugs into 110v outlet, very safe, and I think
>you can even get ones that have thermostats on them. Local plumbing supply
>can probably find them for you.
>my guess is that it would temp the shell of the tank enough to help keep
>the
>pressure high enough to do the trick.
>
>______________________________________________________________________________
>Send postings to clayart@lsv.ceramics.org
>
>You may look at the archives for the list or change your subscription
>settings from http://www.ceramics.org/clayart/
>
>Moderator of the list is Mel Jacobson who may be reached at

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mudlark on fri 15 dec 00

I had the same situation in Colo Sprgs. Tried a bunch of stuff short of a fire under it. Even an old electric blanket didn't work The only thing that worked even down to -10 or below was to run water (cold fron the spigut) over the tank. It doesn't take alot but needs to be a constant trickle. I didn't run it over the valve, lines or any of that stuff but just down one side of the middle of the tank. Works every time.

Mark/El Rossier wrote:

> Gotta question for you.
>
> I am not new to firing at all, but new to propane. I run my 60ft3 kiln off of a 500 gallon tank and have twice now had the all-too-familiar pressure drop as the sun sets and the air temperature drops. I know that when it gets cold, you lose propane pressure. I also know that volume in the tank greatly affects pressure. The first time I had cones moving, the valve wide open and I was just plain losing temperature. I shut the kiln down. The second time I had more volume in the tank, but it still took the gas wide open to keep it going and we started to pour water on the frosted line to try to warm things up. We just made temperature either by luck or the garden hose, I don't know which.
>
> My question is, is there any trick or gadget to help with this situation? I could always have a full tank when I fire, but that would mean the propane company would deliver to me once or twice a week! The last firing I started with 45% in the tank-- I thought I was safe. I am not interested in any solutions that are questionable in their safety,( for instance, I will not try to invert my 500 gallon tank or build a fire under it or any such silliness.) I vaguely remember Jeff Oestrich mentioning something he and Linda Christiansen use in such situations to warm things up. I sure would appreciate some advice.
>
> I am not a regular clayart member, so I would appreciate responses being sent to my address: markel@indra.net
> Thanks so much.
>
> Mark Rossier
> Boulder CO
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at melpots@pclink.com.

Tom Wirt/Betsy Price on fri 15 dec 00

From: Nils Lou
Subject: Re: Cold Propane

> Tom, why don't you use liquid withdrawal burners? Absolutely no
freeze-up
> problems at any temp. It is the solution for propane, especially
across
> the
> northern tier of states.

Hi Nils, Yes, we absolutely should have used them. But when we put
in the installation, the gas company said the usual "no problem".
And we haven't had any problem, I guess just by chance, until this
most recent freeze-up. And now the guys who said "no problem" say,
well we didn't think one tank would be enough, don't know how you got
along till now! Anyway. yes, absolutely, if you're firing up here
right next to Canada, get the liquid tappers from Nils.

We also found out that they sometimes mix butane with propane, and if
there's too much butane in the mix, it can cause early freeze- up.

And now we know some more of the story.

Tom Wirt

Getting ready for another Alberta Clipper

Jean Todd on sat 16 dec 00

> The best advise is for you to exchange your 500 gal tank for a 1000
> tank. If not that hook another 500 gal together so that you draw from
> both at the same time. Tracy
>
I had 2 x 45 kgs hooked to-gether so as to be able to use one or the
other with a flick of the handle. I would start firing with the
emptyier one until the cylinder started freezing or the pressure
started dropping, then I would switch over. Found also a hose just
dripping on the top would unfreeze a cylinder of gas. When firing
finished I would use the gas in the emptier bottle to soak. Had a
wooden sign saying "Empty Bottle" on the emptier one so when the man
came to swap empty bottle for a new full one he knew which to take,
and he would put the sign over to the other bottle which was now the
"emptier one". Do not advise drawing from two to-gether as both will
give out just when you need that extra bit to finish a firing.
Jean from Cowra, NSW
mallyree@ix.net.au

Logan Oplinger on sun 17 dec 00

A possible solution. Temporary, if you have a gas hot water heater, run =
the soaker hose from there. More permanent, recover "waste" heat from ch=
imney using water run through a heat exchanger (metal pipe coil at top of=
chimney), & use the heated water to soak propane tank.

Logan Oplinger

---- you wrote:=20
> Only problem is, Gail, Mark's propane tank is in Rocky Mountain Colorad=
o. At=20
> this time of year a soaker system like you describe would freeze solid.=
=20
>=20
> Ned (old studio buddy of Mark Rossier)
>=20
> =97=97=97=97=97=97=97=97=97=97=97=97=97=97=97=97=97=97=97=97=97=97=97=97=
=97=97=97=97=97=97=97=97=97=97=97=97=97=97=97
> In a message dated 12/14/00 2:27:10 PM, gailnichols@OPTUSNET.COM.AU wri=
tes:
>=20
> >I use a garden 'soaker hose'.....a flat plastic hose with lots of ver=
y
> >fine holes in it. Wrap it around the gas cylinders (one length of hos=
e does
> >2 cylinders), attach the other end to the water tap, then just turn on=
the
> >water as you need it. Seems to solve the problem of freezing cylinde=
rs
> >OK, without enormous amounts of water going everywhere.
> >
> >Gail Nichols
> >Sydney, Australia
> >gailnichols@optusnet.com.au
>=20
> _______________________________________________________________________=
_______
> Send postings to clayart@lsv.ceramics.org
>=20
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>=20
> Moderator of the list is Mel Jacobson who may be reached at melpots@pcl=
ink.com.
>=20

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