Danger gen clear reservoir

[Nomad2000]

What do you think about a Danger Den clear reservoir? It hasn't got any hole for the air. Can it work without the hole?
Thank everybody.

[redleader]

What good would a hole do

[Nomad2000]

I think - air in the reservoir should communicate with air outside of the reservoir so that to have the same pressure. Maybe I am wrong?

[gmat]

Hummmm why so ?
Air in your circuit will collect there.
I really dont see why it would need to escape outside. Unless you're *adding* air to your circuit...

[Nomad2000]

I think that if a reservoir hasn't got a hole, air in it doesn't let air from my circuit go to the reservoir. Again, maybe I am wrong. But, after all, air is incompressible, so air from my circuit must force out air from the reservoir outside. If the reservoir hasn't got a hole, then - how can air do it?

[RickCain]

It's toooooooo small.... I have the blue cube version and all it's good for is creating foam.

[Sanjuro]

You'd probably be better off with an electrical junction box, or just go with an inline pump

[lead]

Nomad2000

I think you said that wrong

But, after all, air is incompressible

I think when you have incompressible air--you have a flat. I may be wrong--Have been before---but my air compressor is gonna be pissed.

[ECUPirate]

hehe... no guys, you don't need a hole in the res. air will collect there if it's designed properly. Also, if the res isn't the highest point in the system, opening the top will result in major spillage. I have a rather large res... it, and all of my WC gear, is located in it's own box, a few feet away from my PC. I can change out waterblocks, and reroute hose, (read: take the hose off of the waterblock, or open up the circuit) with zero spillage. *pump must be off * Just keep the block above the level of the other components. As soon as the hose comes off, it will drain back into the res. Put teh new block on, and turn on the pump. Voila! The water displaces the air in the hose, which returns to the res! No bleeding necessary.

[FRAGN'STIEN]

I don't have a hole in mine, it's unnessasary(sp?) you don't want to fill the res all the way to the top anyway. This will give the air somewhere to go. If you did have a hole, evaporation would probably be an issue.

[Cyco-Dude]

thats a myth ECU. it doesnt matter where the airtrap is located, opening it will not result in the water spilling out. Cornerjack proved this with his setup (his res is above his WB, but below his rad).

[ECUPirate]

you're partially correct. if you take an open topped bucket of water and set it on the ground, and the take a hose full of water and put both ends of the hose in to bucket, forming a loop, then no, the water won't leave the hose. but if you open the loop, i.e., remove a waterblock, then you've got a problem.

[Cyco-Dude]

well, you wouldnt have the res open obviously

[bigben2k]

Ya'll got it right. if you have a res, and it has an air hole, it's preferable for it to be at the top, for safety's sake, because if something leaks, then that res would leak the fluid out.

I was wondering why we'd need an airhole in a res, so I looked it up.

According to the Machinery's handbook (26th ed), water changes in volume at different temps as follows:
Where water at 39.1 deg F is 1.00000
68F 1.00171
77F 1.00286
86F 1.00425
95F 1.00586
104F 1.00767

In short, the volume of water will increase by about 0.25%, as it goes from 68F to 86F. This increase will result in an increased overall pressure in the system, unless it has a hole.

Now, that increase is not significant, and in a 1/2 gallon system, the added volume would be about 5 mL, or 25 drops of water. The effective pressure increase, of the air (since water is incompressible) is probably negligeable, but would depend on the amount of air in the system.

The clamps that we use should be sufficiently tight to compensate for any of that. In a sealed system with no air whatsoever, it might be a bigger factor.

There is something to keep in mind though, for those that let the pump run all the time: if your rad fans aren't turning as well, then your water temp probably rises to somewhere around 104F, which would result in twice the above pressure increase. Still insignificant, but it does add to the total pressure. Combined with a sealed system with no air, I think that it might become a problem.

[Hallis]

The ONLY problem i could see with not having a hole in the res is... When the water gets warm it expands,, which puts pressure aginst the air and likewise aginst the system. An air hole would release this pressure. Although i dont think that the pressure if enough to matter that is the only rational explanation i could think of for such a hole in a res. unless you're just looking for another possable place for water to leak out of.

[Hallis]

damnit big ben you must type faster than i do,, lol

[bigben2k]

Originally posted by Hallis
damnit big ben you must type faster than i do,, lol

Now we have numbers!

[Hallis]

yah i just find it odd that we both had basically the same responce :-) brilliant minds think alike i guess,, either that or i just really need to get some sleep. Oh also about the TEC post that wayne made about his problems.. lots of good info you had to offer.. made the thread an awesome read.. do you have much PELT/TEC experience? if so i really would like to chat you up about setting up a system to get the real cool on :-)

[bigben2k]

No experience yet, but it's pretty easy for me to understand the theory, and you know, if you understand the theory, then you understand almost everything.

There's lots of good information here.

[nemaste]

BTW,

air is very much compressible, water is relatively incompressible. most h2o systems will have at least some air in the system (in the res or air-trap of a well designed setup). sealing sealing the system can cause expansion & contraction of this air that will in fact create a net pressure difference between the system & ambient atmosphere. this is bad IMHO, because heating, cooling, & barometer changes will either lead to 1) a vacuum that can potentially suck air through a weak seal or 2) water pressurization, which can similarly cause leaks.

since water won't evaporate much through a very small opening & only a small opening is required to equilibrate the pressure, i setup my system to have the best of both worlds. by barely loosening my filler cap, i am not loosing water & i am assured i'm not building up any net pressure (i keep it tightened & sealed only during travel to eliminate spills).

[gmat]

Let's clear that up, there are 2 distinct cases.
1- closed loop, *no* airtrap (and no res). This is OT here so we dont consider this.
2- closed loop with an airtrap (this thread topic). Let's say the airtrap is filled at 2/3, which for a small-sized airtrap gives about 10cl of air for 20cl of water. Let's say you have 1l of water in the system (im guesstimating here, i think it's quite a big figure).
Water temps rise about 2°C in most systems, heck lets say it rises 5°C.
The 1l of water becomes 1.00138l, thats 1.38cl more in volume. So the 10cl of air become 8.62cl.
If the air was initially at atmospheric pressure, it will then be at 1.16atm (assuming a linear pressure raise, we're on a small scale). This is negligible.
The main reason one doesnt care is the water *weight* itself creates way more pressure in lower parts of the circuit. If your circuit doesnt hold a 1.16 factor of pressure rise then you've got way worse problems at hand, to begin with...

So my take is seal it, that'll prevent any leakage. One makes mistakes, and Murphy's law says they always happen at the worse time.

[bigben2k]

Right on gmat, but I think you meant that the 1L of water becomes 1.00138, that's 1.38 mL (not cL) more in volume. So the 10cL of air becomes 9.9 cL, resulting in a very small, almost insignificant diff in air pressure.

The water weight, combined with the pressures caused by the flow, far, far outweighs the amount of pressure that thermal expansion of water can provide.

I also think that the important point here, is to answer the thread! No, no air hole is not a problem for the DD res. If possible though, it would be preferable to leave a small amount of air in the system.

If there is no air whatsoever, then the thermal expansion of the water would be covered by... the flexibility in the tubing, as it expands (since water is mostly incompressible). I don't believe that that's something any of us want to rely on.

[ECUPirate]

Water is so compressible! LIke, when you're taking a leak, and the phone rings, and you have to squeeze it off mid-stream... What do you do? Compress water.

[BaconGrease]

Originally posted by ECUPirate
Water is so compressible! LIke, when you're taking a leak, and the phone rings

LOL!

One possible/interesting alternative to a vented reservoir would be reservoir that could accomodate for pressure differentials.
One example would be to have an elastic cover (balloon) that would allow for air expansion when the temp increases, but would then collapse down when cool.
This would still keep a closed system and keep you from needing refills as often.

[bigben2k]

Originally posted by BaconGrease

One possible/interesting alternative to a vented reservoir would be reservoir that could accomodate for pressure differentials.
One example would be to have an elastic cover (balloon) that would allow for air expansion when the temp increases, but would then collapse down when cool.
This would still keep a closed system and keep you from needing refills as often.

Also known as a diaphragm, is used to maintain constant water pressure where well water is available, because the whole thing is sealed, so the air pressure compensates for the lack of water pressure.

In this case, we just wouldn't want the air pressure at all.