What is this part on my "CO2" tank? - The Planted Tank Forum
 
LinkBack Thread Tools Display Modes
post #1 of 11 (permalink) Old 01-03-2011, 11:10 PM Thread Starter
Planted Tank Obsessed
 
PTrader: (0/0%)
Join Date: Mar 2010
Location: Grand Junction, CO
Posts: 423
What is this part on my "CO2" tank?

I took my tank in to be filled today and when the guy started filling it a small rubber cap blew off of the nipple looking thing to the left in this picture. When he put CO2 in the tank it would just burst back out of that little tube.



It is actually a compressed air tank for paintball, but I was going to use it for a CO2 tank for my aquarium.

It has a couple plugs on it that I was told are burst valves. Can anyone confirm this? It also has a gauge as well as whatever this thing is that had the rubber cap on it.

Here is the view from the other side of the tank.




Just a few questions before I take it back to be filled:

1) What is that nipple for, and is it needed?
2) Are those actually burst valves as a safety precaution or something else?
3) Can I just take that "nipple" out and get a bolt with the same thread and cap that hole so I can fill the tank?
mmelnick is offline  
Sponsored Links
Advertisement
 
post #2 of 11 (permalink) Old 01-03-2011, 11:24 PM Thread Starter
Planted Tank Obsessed
 
PTrader: (0/0%)
Join Date: Mar 2010
Location: Grand Junction, CO
Posts: 423
I just took that nipple off and this is what the back side (that was screwed into the tank) looks like.

mmelnick is offline  
post #3 of 11 (permalink) Old 01-04-2011, 12:24 AM
Algae Grower
 
ThatPlantedAquariumGuy's Avatar
 
PTrader: (7/100%)
Join Date: Mar 2010
Location: Central Florida
Posts: 81
Quote:
Originally Posted by mmelnick View Post
I took my tank in to be filled today and when the guy started filling it a small rubber cap blew off of the nipple looking thing to the left in this picture. When he put CO2 in the tank it would just burst back out of that little tube.



It is actually a compressed air tank for paintball, but I was going to use it for a CO2 tank for my aquarium.

It has a couple plugs on it that I was told are burst valves. Can anyone confirm this? It also has a gauge as well as whatever this thing is that had the rubber cap on it.

Here is the view from the other side of the tank.




Just a few questions before I take it back to be filled:

1) What is that nipple for, and is it needed?
2) Are those actually burst valves as a safety precaution or something else?
3) Can I just take that "nipple" out and get a bolt with the same thread and cap that hole so I can fill the tank?
I'm not 100% sure about your last question, but the part you're referring to is a fill nipple. Often times, these are used instead of the main connection to fill the co2 tank as they will have a small filter inside to prevent debris and metal shavings to go inside your bottle (for paintball players, debris or metal shavings could damage the internal mechanics of paintball markers).

Many players prefer to not have these or to remove them since they take much longer to fill the bottle than using the standard connection. I suspect, although I may be wrong, that when the guy started filling your tank today, he didn't properly account for the fill nipple, causing the burst valve or something else to go. There are burst valves installed on all pressurized canisters which will usually open when a certain pressure has been exceeded. This prevents the bottles from turning into violent, shrapnel-throwing bombs.

My thoughts are that he may have damaged the burst valve, and I'm not sure you can easily replace that yourself or at a low enough cost that would justify not simply purchasing a new paintball tank. Hopefully someone on the forum will know more specifics about it then I do. But at least you know what it is and what it's used for now.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
ThatPlantedAquariumGuy is offline  
 
post #4 of 11 (permalink) Old 01-04-2011, 01:03 AM
Moderator
 
Darkblade48's Avatar
 
PTrader: (3/100%)
Join Date: Jan 2008
Location: Toronto/Singapore
Posts: 11,476
A better question is this.

Are you trying to fill a compressed air cylinder with CO2? The filler at the shop clearly does not know what he is doing, as this should not be done for safety reasons.

I also strongly recommend against filling cylinders with gases they were not designed to hold.

Anthony


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
and
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Eheim Pimp #362 - Eheim 2213 x2, Eheim 2028, Eheim 2217, Eheim surface skimmer and Eheim autofeeder.
Victor Pimp #33 - HPT272-125-350-4M
Darkblade48 is offline  
post #5 of 11 (permalink) Old 01-04-2011, 01:47 AM Thread Starter
Planted Tank Obsessed
 
PTrader: (0/0%)
Join Date: Mar 2010
Location: Grand Junction, CO
Posts: 423
Quote:
Originally Posted by ThatPlantedAquariumGuy View Post
My thoughts are that he may have damaged the burst valve,
There was a rubber cap on that fill valve that blew off, so the gas was coming out from there for sure.

And thanks for the info on that part. I think I'll just remove it then.

Quote:
Originally Posted by Darkblade48 View Post
A better question is this.

Are you trying to fill a compressed air cylinder with CO2? The filler at the shop clearly does not know what he is doing, as this should not be done for safety reasons.

I also strongly recommend against filling cylinders with gases they were not designed to hold.
Yes, I'm filling an air tank with CO2. I've read online about others doing it (for paintball) without issue.

Why would 800 PSI of CO2 be more dangerous in that tank than 3000 PSI of air?
mmelnick is offline  
post #6 of 11 (permalink) Old 01-04-2011, 03:26 AM
Planted Tank Guru
 
PTrader: (84/100%)
Join Date: Dec 2005
Location: Sacramento, CA
Posts: 21,015
Air tanks are often converted to CO2 tanks by installing a CGA320 valve on the tank. That is the only difference in the tanks, other than the tank color. That particular tank valve is unique to my experience, probably because I have no experience at all with paint ball equipment.

The best reason the tank shouldn't be filled with CO2 by that particular vendor is that he clearly doesn't know how to do it. I would worry that he would overfill the tank as a result.

Hoppy
Hoppy is offline  
post #7 of 11 (permalink) Old 01-04-2011, 04:18 AM Thread Starter
Planted Tank Obsessed
 
PTrader: (0/0%)
Join Date: Mar 2010
Location: Grand Junction, CO
Posts: 423
Quote:
Originally Posted by Hoppy View Post
I would worry that he would overfill the tank as a result.
That was my only concern with this whole CO2 in an air tank experiment.

But I told him to put in 24 oz. And according to the google calculator 48 cubic inches (the size of the air tank) = 26.5974026 US fluid ounces.
mmelnick is offline  
post #8 of 11 (permalink) Old 01-04-2011, 05:01 AM
Planted Tank Guru
 
PTrader: (84/100%)
Join Date: Dec 2005
Location: Sacramento, CA
Posts: 21,015
Quote:
Originally Posted by mmelnick View Post
That was my only concern with this whole CO2 in an air tank experiment.

But I told him to put in 24 oz. And according to the google calculator 48 cubic inches (the size of the air tank) = 26.5974026 US fluid ounces.
You probably told him the wrong amount, but, in any case the guy filling the tank has to know how much weight of CO2 can go into each tank size safely. It isn't up to us to tell them. I think the maximum safe weight of liquid CO2 would be about 0.8 pounds - you need to allow room for the CO2 to warm up to about 100F to avoid over stressing the tank. And, you need to allow a bit more room on top of that for mistakes.

I'm not qualified to fill CO2 tanks, so you can't rely on my calculation.

Hoppy
Hoppy is offline  
post #9 of 11 (permalink) Old 01-04-2011, 07:04 AM Thread Starter
Planted Tank Obsessed
 
PTrader: (0/0%)
Join Date: Mar 2010
Location: Grand Junction, CO
Posts: 423
Quote:
Originally Posted by Hoppy View Post
You probably told him the wrong amount, but, in any case the guy filling the tank has to know how much weight of CO2 can go into each tank size safely. It isn't up to us to tell them. I think the maximum safe weight of liquid CO2 would be about 0.8 pounds - you need to allow room for the CO2 to warm up to about 100F to avoid over stressing the tank. And, you need to allow a bit more room on top of that for mistakes.

I'm not qualified to fill CO2 tanks, so you can't rely on my calculation.
0.8 lbs would be half of the capacity for this tank if it were actually only rated for the PSI of a regular CO2 tank. Why would you suggest that I should have to fill it to such a low capacity?

It seems to me like this tank should be able to hold much more pressure than a regular CO2 tank, so I should be able to fill it to the capacity of a regular CO2 tank without even coming close to the threshold that it was engineered to withstand.

24 oz of CO2 at 800 PSI won't warm up and suddenly be at over 3000 PSI will it?

I can't afford a new CO2 tank right now, so if I can't make this work I'll just have to go without and possible put off the setup of this new tank. So I'd like to make it work, but if I'm missing something about the way CO2 works I would scrap this tank to avoid an explosion or whatever. I'd just like to know why a stronger tank can't be filled 1/2 as much as a weaker tank designed for CO2???
mmelnick is offline  
post #10 of 11 (permalink) Old 01-04-2011, 04:04 PM
Planted Tank Guru
 
PTrader: (84/100%)
Join Date: Dec 2005
Location: Sacramento, CA
Posts: 21,015
CO2 and air are different. When CO2 is under pressure it is a liquid, but air remains a gas, no matter how high the pressure. A tank of CO2 will normally have mostly liquid CO2 in it, with gas on top of the liquid. When you fill the tank, the CO2 is very, very cold, so it "shrinks" to occupy less volume than when it is at 100F. If you fill the tank completely with liquid CO2, as it warms up it expands. Since there is no room for the expansion other than stretching the tank, the tank either pops its relief valve, as it is supposed to, or the tank explodes from the pressure. For that reason CO2 tanks cannot ever be completely filled with liquid, so they are filled by weight. The weight of CO2 added is that of an amount of liquid CO2 that will not completely fill the tank when the liquid CO2 warms up to 100F or some similar temperature. The gaseous CO2 on top of the liquid CO2, is also warming up, and increasing in pressure proportional to the absolute temperature of the gas. That's why a newly filled tank, still frosty on the outside, will have a pressure as low as 500 psi, but when it warms up to room temperature, the pressure will be 700-800 psi, depending on the room temperature. The liquid CO2, the gaseous CO2, the volume of gaseous CO2 and the pressure in the tank are all in an equilibrium at all times, with gas changing to liquid and vice versa as temperature changes, and as CO2 is used.

The relief valve on a CO2 tank is there as a second line of defense against the tank exploding. You can't legally fill a CO2 tank so full that the relief valve pops open as the tank warms up - the guy filling the tank is supposed to be licensed to do so, demonstrating that he understands all of this stuff.

Hoppy
Hoppy is offline  
post #11 of 11 (permalink) Old 01-04-2011, 04:43 PM Thread Starter
Planted Tank Obsessed
 
PTrader: (0/0%)
Join Date: Mar 2010
Location: Grand Junction, CO
Posts: 423
Quote:
Originally Posted by Hoppy View Post
CO2 and air are different. When CO2 is under pressure it is a liquid, but air remains a gas, no matter how high the pressure. A tank of CO2 will normally have mostly liquid CO2 in it, with gas on top of the liquid. When you fill the tank, the CO2 is very, very cold, so it "shrinks" to occupy less volume than when it is at 100F. If you fill the tank completely with liquid CO2, as it warms up it expands. Since there is no room for the expansion other than stretching the tank, the tank either pops its relief valve, as it is supposed to, or the tank explodes from the pressure. For that reason CO2 tanks cannot ever be completely filled with liquid, so they are filled by weight. The weight of CO2 added is that of an amount of liquid CO2 that will not completely fill the tank when the liquid CO2 warms up to 100F or some similar temperature. The gaseous CO2 on top of the liquid CO2, is also warming up, and increasing in pressure proportional to the absolute temperature of the gas. That's why a newly filled tank, still frosty on the outside, will have a pressure as low as 500 psi, but when it warms up to room temperature, the pressure will be 700-800 psi, depending on the room temperature. The liquid CO2, the gaseous CO2, the volume of gaseous CO2 and the pressure in the tank are all in an equilibrium at all times, with gas changing to liquid and vice versa as temperature changes, and as CO2 is used.

The relief valve on a CO2 tank is there as a second line of defense against the tank exploding. You can't legally fill a CO2 tank so full that the relief valve pops open as the tank warms up - the guy filling the tank is supposed to be licensed to do so, demonstrating that he understands all of this stuff.
OK, thanks. Very helpful.

The guy filling the tank clearly knew none of this.
mmelnick is offline  
Reply

Tags
None

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the The Planted Tank Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome