Tank and regulator in the fridge question

[patrad]

A guy at local hombrew gas shop was telling me keeping the regulator and gas in my keggerator will throw off the indicators and make it seem like my tank is empty. I've been having leakage issues and would like to move my tank and regulator outside of the fridge so some questions:
1) What affect does the cold temp have on the tank and regulator?
2) I have a Danby DAR440BK and while I could fit two kegs with the tank inside, I would like to move the tank and regulator outside of it. Is there a shank like thing I could use for gas rather than just drilling a hole in the side and running a gas tube line?

 

[patrad]

also, this is the regulator I'm using if it matters http://www.northernbrewer.com/shop/dual-gauge-co2-regulator.html

 

[FloppyKnockers]

1) Simply put, it makes the regulator display a lower pressure than actually in the tank.
2) Shank type thing? If you really don't want it in the fridge for the lack of gauge reliability, a hole in the back/side/bottom would be the best way to go.

 

[yohoe]

A guy at local hombrew gas shop was telling me keeping the regulator and gas in my keggerator will throw off the indicators and make it seem like my tank is empty. I've been having leakage issues and would like to move my tank and regulator outside of the fridge so some questions:
1) What affect does the cold temp have on the tank and regulator?
2) I have a Danby DAR440BK and while I could fit two kegs with the tank inside, I would like to move the tank and regulator outside of it. Is there a shank like thing I could use for gas rather than just drilling a hole in the side and running a gas tube line?

CO2 is a liquid at -78C to 56C and a gas at >56C at 1 atm. The gauge reads the amount of pressure exerted by the gas inside the tank, which is lower at lower temperatures. This can be explained by the ideal gas law: PV=nRT. Decrease T = decreased P if V stays constant. I'm not sure about a shank but I drilled a hole and ran brass fittings through the hole. You can see my setup here

 

[doug293cz]

1) Simply put, it makes the regulator display a lower pressure than actually in the tank.
2) Shank type thing? If you really don't want it in the fridge for the lack of gauge reliability, a hole in the back/side/bottom would be the best way to go.

This is incorrect. Until a CO2 tank gets down to 5-35% (depending on temperature) of capacity, there is both liquid and gas CO2 in the tank (unless the tank temp gets over about 88°F, in which case there is only gas in the tank.) When liquid and gas are in equilibrium, the pressure depends only on the temperature of the tank, and nothing else. The pressure says nothing about the amount of CO2 in the tank, until all the liquid is gone. The pressure gauge correctly reads the pressure in the tank whether it is at cooler temps or room temp. The pressure in the tank is lower at lower temperatures.

The graph below shows what the pressure inside a CO2 tank is vs. fill level of the tank. Pressure curves are shown for a variety of different temperatures. You do not need to worry about the part of the graph for greater than 100% full. You can see that for all temperatures (below about 88°F) that pressure is constant for at a given temperature until the tank gets near empty. In the lower left corner of the graph, you see the curves start bending downwards. The bend point for a particular temperature is the tank percent full where all of the liquid is gone, and only gas remains in the tank.

Some useful information you can pull off of the chart:

1. The pressure gauge readings will change as the tank changes temperature.
2. If you don't know the temp of your CO2 tank, the gauge reading is useless (unless it is above 2000 psi, in which case your tank is dangerously hot.)
3. With the tank at room temp (~70°F) the gauge reading will not start dropping until you have only about 30% (1.5 lbs in 5 lbs tank) of your CO2 left.
4. With the tank at keg temps (~40°F) the gauge reading will start dropping at about 15% (0.75 lbs in 5 lb tank) of your CO2 left.
5. Don't leave a full (or nearly full) tank anywhere that can get above 120°F, as you risk having the tank blow out.

Brew on

 

[doug293cz]

CO2 is a liquid at -78F to 56F and a gas at >56F. The gauge reads the amount of gas, therefore giving you the wrong reading in the keezer. I'm not sure about a shank but I drilled a hole and ran brass fittings through the hole. You can see my setup here

This is incorrect. CO2 is a gas at atmospheric pressure above it's boiling point, which is -108.76°F (-78.2°C) [ref: http://en.wikipedia.org/wiki/Carbon_dioxide_data]. CO2 can be liquefied above it's boiling point when pressurized, unless the temperature is above about 88°F (the critical point of CO2.)

The pressure gauge reads gas pressure, not amount of CO2. When there is liquid in the tank, the pressure only depends on the temperature of the tank, and nothing else. See my previous post.

Brew on

 

[patrad]

I see plenty of people keeping their gas in keggerator/keezers. . . is there any benefit to not doing so?

 

[wilserbrewer]

I see plenty of people keeping their gas in keggerator/keezers. . . is there any benefit to not doing so?

Keeping the CO2 outside will give you more room inside

In humid climates, a freezer keezer can get humid, long term this could be a little tough on a regulator and tank but no real concerns....

 

[MerlinWerks]

2) I have a Danby DAR440BK and while I could fit two kegs with the tank inside, I would like to move the tank and regulator outside of it. Is there a shank like thing I could use for gas rather than just drilling a hole in the side and running a gas tube line?

Bulkheads are available. HERE is one example...

 

[yohoe]

This is incorrect. CO2 is a gas at atmospheric pressure above it's boiling point, which is -108.76°F (-78.2°C) [ref: http://en.wikipedia.org/wiki/Carbon_dioxide_data]. CO2 can be liquefied above it's boiling point when pressurized, unless the temperature is above about 88°F (the critical point of CO2.)

The pressure gauge reads gas pressure, not amount of CO2. When there is liquid in the tank, the pressure only depends on the temperature of the tank, and nothing else. See my previous post.

Brew on

You are correct. I used F instead of C - I knew i should've used Kelvin lol. For all intensive purposes, I assumed are working at 1 atm. I made the correction accordingly.

 

[Stealthcruiser]

You are correct. I used F instead of C - I knew i should've used Kelvin lol. For all intensive purposes, I assumed are working at 1 atm. I made the correction accordingly.

That's "intents and purposes......"

 

[yohoe]

I see we've deviated away from the thread topic...

That's "intents and purposes......"

Please PM me next time to correct me on my English so we don't have to take away from the actual topic.

...and we're back...

 

[Stealthcruiser]

Lighten up, twas' a joke.......................

 

[wilserbrewer]

I always thought it was intensive porpoises

Thanks, I'll try to remember this...

 

[wilserbrewer]

View attachment ImageUploadedByHome Brew1420757134.321586.jpg

 

[wilserbrewer]

OK, on a more serious note, I feel I owe the group a straight answer....

A guy at local hombrew gas shop was telling me keeping the regulator and gas in my keggerator will throw off the indicators and make it seem like my tank is empty.

NOT TRUE AT ALL!

I've been having leakage issues and would like to move my tank and regulator outside of the fridge so some questions:

Go over your entire system and CAREFULLY AND THOROUGHLY check for leaks with a bubble foam, you can use soap bubbles or I use star san foam whipped up good. Some have even resorted to submerging their entire system underwater in a garbage can. Even the tiniest of leaks will drain your CO2 tank pretty quickly. You must check ALL connections and eliminate any leaks!!!!

1) What affect does the cold temp have on the tank and regulator?

Your tank pressure will read less, your line pressure to the beer, what really matters will still be accurate! So for all intents an purposes, storing the tank and reg inside or outside makes no difference. Storing outside leaves more room inside for beer!

2) I have a Danby DAR440BK and while I could fit two kegs with the tank inside, I would like to move the tank and regulator outside of it. Is there a shank like thing I could use for gas rather than just drilling a hole in the side and running a gas tube line?

Yes there are fittings available, or even a manifold to split b/w the two kegs. In my simple opinion, the more fittings the greater chance of leaks. I run the CO2 line in my beer fridge, and use a simple cheap TEE fitting to supply two kegs. This does not allow two different pressures, but you can still force carb by disconnecting one keg for 36 hours and force carbing the second keg.

For reference, all pressures are the needle on the gauge, temperatures in Fahrenheit, and pv=nrt was so long ago, now I barely remember RHCP