20lb Propane Tank Pressure Loss???

by the charts that fitzo linked to it showed that temperature makes a pretty noticible differance. also since when you decompress the tank it cools, it has less temperature change to go through until it freezes.

you can always try when the psi dramaticaly drops, to (with the valve in the off posistion) to gently shake/rock the tank to see if there is a chunk of frozen propane in it (becareful with this, i do not see much danger as long as it is closed and no flames around but im not taking any liability.)

im taking this info from my experances with co2 again, espicaly when there is a substantial decompression the gass will freeze and form a huge chunk (enough in co2 tanks that you can replace burst disk that blows out when the psi spikes and still have a full tank when the chunk melts )

-matt
 
It was real cold. High of 22, low of 11. So the temperature in the garage was probably low teens when I went out there.
 
Alex

I can sympathize

I have had similar problems in the past.

A sudden and extreme loss of pressure, unrelated to freezing up from high flow.

I have several 20 lb tanks, some “old style” and some “new style” valves.

The problem occurs with the new style.
Apparently on the tanks with the new style connectors have safety features which can be a PITA

Ensure that any O-Rings which should be there are there.
Ensure that the O-Rings didn’t “double-up” and jam an extra inside the connector, preventing full insertation.
Ensure the fittings are lining up correctly and not canted, preventing full insertation.
Ensure the fittings are tightened up well to activate the safety flow valve (similar in concept to a quick disconnect compressed air fitting-air flow shut off when disconnected)


As Matt said….
“there is a valve inside the tank that shuts off if the internal pressure drops too abruptly.”

I personally have a lot of problems with this one.
I am used to opening a tap a certain way, apparently it is too fast.
Shut off the valve and open it again, very very slooooooly.

I have only seen this safety valve on 20 Lb sized tanks.
As suggested by Stacy, switching to a 100 lb tank would cause less problems and require fewer fillings also.
A less drastic measure is to connect 2 or more small tanks together using a manifold, or Y connectors to achieve the same result



For those who experience freezing, a radiator connected at the tank can help the expanding propane to absorb heat from the air.

Take a look at some industrial sites with external bulk compressed gas tanks. They are often accompanied by huge heat sink towers that look like hot water heating radiators.

In addition to others, I believe photos on Don Fogg’s site show the concept


Steven Penner
 
Pimp, What's your question ?


From this site

http://www.rd.com/images/tfhimport/...20020401_Ask_Handyman_page004img001_size2.jpg

www.rd.com/content/openContent.do?contentId=19567

If your gas grill is powered with a propane tank, be advised that the tank may no longer be refillable. A code change has taken effect that states that all 4- to 40-lb. propane tank valves must be equipped with an overflow protection device (OPD). This device addresses the danger of tanks leaking because of overfilling. Most major propane suppliers will no longer fill noncompliant tanks.
The OPD valve handle has three lobes (see photo); the non-OPD valves don’t. Your non-OPD tank can be fitted with a new code-compliant valve, but the cost may well exceed the cost of a new tank.

The way i see it is - find a supplier who still fills what you got, then you may be able to buy the non OPD valves at a welding supply shop.

They do work, just that i hate them.

As Stacy said, the bigger the tank, the more flow they are designed to provide. Over 40 lbs avoids this.

Steve
 
Steven Penner said:
I have several 20 lb tanks, some “old style” and some “new style” valves.

The problem occurs with the new style.
Apparently on the tanks with the new style connectors have safety features which can be a PITA
Click to expand...

thats what my question was pertaining to. i have a 35lb tank with a valve that is about a year and a half old. i was wondering if this type will comply with the new codes and has that safety feature.
 
Thanks for the help. I think that opening the tank slowly made the difference.

Thanks again
Alex
 
I use such gas tanks at work all the time, and they always freeze up on me.
I have a Gas forge with the normal gas grill propane tank to it.
I have had the newer tanks freeze up on me.

On advice of a forum member, I got a tub big enough to place my gas tank inside and I place a few gal of warm water in the tub.

This seems to have ended any of the problems I had with tank freeze ups.
I have never had the valve or the gas lines become a problem.

The warm water tub seems to help everything enough.
 
#8 03-07-2007, 07:58 PM
Toxey
Registered User Join Date: Oct 2005
Posts: 52

Ritzblitz I went through the same thing as you when I first started out trying to heat metal.I had the same setup as you.
20# Tank,adapter hose and the same torch.
The adapter has some type of regulator in the connector where it screws into the tank.It will only let so much propane thru at one time.
I tried to "alter,bypass,get rid of",this regulator with no luck at all.

You might want to expand your horizons and try for a little bigger forge with proper insulation such as kaowool coated with the ITC100.
Take a look at this burner setup ,and decide for yourself.

http://www.backyardmetalcasting.com/oliverburner1.html

I used this burner in a freon tank with proper insulation,and this baby gets hot.
 
Pimp

"The OPD valve handle has three lobes (see photo); the non-OPD valves don’t. "

according to the link i posted, see the links for photos

Steve
 
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