Horizontal Sodastream bottle in fridge

[TJP]

I don't currently drink enough to justify a dedicated kegging fridge so my plan is to use a mini keg in the main fridge that I will top up from a corny as a way to avoid bottling.

In order to not have to go through a heap of bulbs, I am hoping to be able to use a SodaStream co2 bottle but it won't fit vertically in my fridge. A lot of information I have read has said this can damage the reg as liquid co2 enters the reg and so I have been looking into anti syphon tubes (http://www.ansgear.com/Anti_Siphon_Tube_Kit_p/pmiantisiphonco2tubekit.htm) predominately used by paint baller's but this would mean I would have to refill myself which I will probably do down the track but in the meantime would prevent swapping cylinders.

After looking into it a bit more and looking at some phase diagrams it looks to me that the co2 in the bottle at fridge temps will likely be gas not liquid, so should, therefore be ok to lay horizontal

I am basing this on the bottle being ≤550psi/38bar at fridge temperature and I think that leaves me just under the saturation line, can anyone who has a co2 tank in the fridge confirm what their psi reading is too see if I have got this correct or if there is anything else I might be missing/getting wrong.

 

[Lyrebird_Cycles]

The soda stream cylinder is marked as having an internal volume of 0.605 litres and contains 400 g CO2 when full, for a net density of 660 kg / m3

That is within the two phase region at normal temperatures, meaning that both liquid and gas will be present in the cylinder.




Graph courtesy the CCS crowd, at last they're good for something.

 

[TJP]

Graph courtesy the CCS crowd, at last they're good for something.

Does that mean I should question it's accuracy? :unsure:

So the saturation line in the other graph is more like a tipping point where the gas/liquid becomes more prevalent than the other but is not all in that state?

 

[woodwormm]

just my 2c. i've dabbled with sodastream bottles to dispense at parties etc.

they are crazy top heavy with an adaptor and reg on them so easily fall over. I usually try to lie them down, but with the reg end propped up. seems to work for me.

can you fit your sodastream bottle into the fridge sortof lying down, but propped up at the business end?

just a thought.

 

[fdsaasdf]

Seems like others have used the sodastream lying down: http://aussiehomebrewer.com/topic/74869-pimp-my-tapking/page-5

Is there any way for the bottle to sit vertically in the fridge door? Not sure if you have a removable butter/split door compartment or conducive housemates

 

[Lyrebird_Cycles]

So the saturation line in the other graph is more like a tipping point where the gas/liquid becomes more prevalent than the other but is not all in that state?

The phase diagram represents end points: if you had CO2 under 6 MPa pressure at 0 oC you could fill a canister entirely with liquid. If you heated it to raise the temperature gradually whilst regulating the pressure at 6 MPa the liquid would begin to vaporise, if you kept this going until you reached a bit over 20 oC all the liquid would vaporise and you would have a new end point.

If instead of going all the way you sealed the canister once say 70% of it had vaporised and kept the temperature constant, it would equilibrate to a new pressure at which the 30% that hadn't vaporised would stay liquid and the headspace would be full of pressurised gas. If you then raised the temperature to say 20 degrees a little bit more would vaporise until a new equilibrium point was reached at a higher pressure. If you then measured the density it would be somewhere around 660 kg / m2.

Basically these intermediate points exist because the material is not able to reach an end point: it can't expand because the canister keeps it under pressure, it has too much energy to stay entirely liquid so both phases are present. The crossovers can be very sharp: I chose 6MPa because you can see that the transition from liquid to gas occurs over a very small range of temperatures.

You can ignore this next bit, it's just a bit of fun:

If instead of venting gas to keep the pressure constant you sealed it and allowed the pressure to rise* as you heated it to over 31 oC something truly weird would happen. Pressurising a gas increases its density, while heating a liquid decreases its density. If you do enough of both you get to the point where the compressed gas has the same density as the heated liquid, so it's neither and both at the same time: it's called a supercritical fluid.

That's the material the hop companies use to make hop extracts, it's a fantastic solvent and once the pressure is released it flashes off leaving no residue.

* Don't try this at home, the bit about the pressure rising is an important caveat: it would end somewhere around 30 MPa, that's something like 5 times the cylinder pressure of a typical full size CO2 cylinder.

 

[TJP]

just my 2c. i've dabbled with sodastream bottles to dispense at parties etc.

they are crazy top heavy with an adaptor and reg on them so easily fall over. I usually try to lie them down, but with the reg end propped up. seems to work for me.

can you fit your sodastream bottle into the fridge sortof lying down, but propped up at the business end?

just a thought.

To get it to fit with the reg on the end it would have to go in on an angle so this might be the best option, the adapter from the bulk buy was hopefully going to allow me to lay it flat for a neater/more compact setup but on an angle might be the best short-term solution.

Seems like others have used the sodastream lying down: http://aussiehomebrewer.com/topic/74869-pimp-my-tapking/page-5

Is there any way for the bottle to sit vertically in the fridge door? Not sure if you have a removable butter/split door compartment or conducive housemates

I messaged Mattwa and he said he only used his laying down for a short time but his reg is still in use and working fine, Captain Morgan hasn't been active on here for 2 years so I didn't msg him to see how he went. What is the reason people say getting liquid co2 into a reg can kill it.

 

[Lyrebird_Cycles]

What is the reason people say getting liquid co2 into a reg can kill it.

I believe that the problem is actually with the equipment downstream of the regulator. If the regulator is allowed to pass liquid CO2 and the liquid then vaporises it will produce high pressure gas. This gas is unregulated and may exceed the pressure rating of the equipment.

As an example, if the regulator allowed half the sodastream cylinder to empty into a 4 litre minikeg in your fridge, the vaporised gas would hit a pressure of nearly 3 MPa (about 400 PSI in Septic units). You'd want to know the PRV was working.

 

[moonhead]

I believe that the problem is actually with the equipment downstream of the regulator. If the regulator is allowed to pass liquid CO2 and the liquid then vaporises it will produce high pressure gas. This gas is unregulated and may exceed the pressure rating of the equipment.

As an example, if the regulator allowed half the sodastream cylinder to empty into a 4 litre minikeg in your fridge, the vaporised gas would hit a pressure of nearly 3 MPa (about 400 PSI in Septic units). You'd want to know the PRV was working.

I would imagine your gas lines would blow before the PRV?

 

[Lyrebird_Cycles]

Not likely, even common 8mm OD x 6mm ID PE hose has a burst pressure > 3 MPa.

The burst pressure for any hose is easily calculated from

Material strength * 2 * WT / ID.

The strength of high quality PE is generally taken as about 10 MPa because it is known that it will withstand this stress for many, many years.