The impact of tubing sizes

[Marci]

He outlined the components necessary in the OP, used Realworld data for the various parameters... it's up to the endusers to test the theory out in RW conditions. Anyone with a rig matching the original specification can check it all out by repiping from their current to any suggested tubing in the OP and validate their results against the theoretical results.

Rig Spec:

Laing DDC1+ (unmodified)
Thermochill PA120.2 with 2 x Yate-Loon fans at 12v
Swiftech Apogee GTX
Conroe C2D CPU, overclocked and under load, emitting 100W of heat
2 meters of tubing length

Change current tubing over to any of the suggested (other than current, obviously)

6.35 (1/4") ID tubing with quick-fit fittings
8mm (5/16") ID tubing over 6mmID|8mmOD barbs
8mm (5/16") ID tubing with quick-fit fittings
9.6mm (3/8") ID tubing over 7.5mmID|3/8"OD barbs
9.6mm (3/8") ID tubing with quick-fit fittings
11.1mm (7/16") ID tubing stretched over 10.5mmID|1/2"OD barbs
12.7mm (1/2") ID tubing over 10.5mmID|1/2"OD barbs

Then validate against

Final CPU temperature is ambient (22C) + system load (114W) * radiator C/W + CPU Load (100W) * block C/W

The final CPU temperatures work out to be:

6.35mm quick fit = 34.21C
8mm barbed = 34.08C
8mm quick fit = 33.91C
9.6mm barbed = 33.89C
9.6mm quick fit = 33.80C
11.1mm barbed = 33.79C
12.7mm barbed = 33.77C

Can't expect Cathar to do ALL the work - he's given everyone the foundation to decide for themselves, and the necessary info to validate for themselves (obviously, account for change in ambient if one exists)... time will provide the realworld-condition tests.

[gabe]

Interesting you mentioned the fluid transfer through the tubing wall. It's not something I've seen a lot of mentioned here, but I'd think it'd be a problem and concern for long-term setups.

I was doing a bit of reading on Saint-Gobain's website (mfgr. of Tygon), which is tygon.com or labpure.com, and the water absorption rates for various formulations of their tubing is listed.....but you have to dig for it.

Definition:
ASTM D570-98(2005)
Title: Standard Test Method for Water Absorption of Plastics
This test method covers the determination of the relative rate of absorption of water by plastics when immersed. This test method is intended to apply to the testing of all types of plastics, including cast, hot-molded, and cold-molded resinous products, and both homogeneous and laminated plastics in rod and tube form and in sheets 0.13 mm [0.005 in.] or greater in thickness

Water Absorbtion rate is NOT the information you are seeking.

Permeation rate is the relevant info, also called the WVTR or Water Vapor Transmission rate, and it is usually measured in Grams per mil thickness per 100 sq inches per 24 hours at 73F, 50% relative humidity.

Definition:
WVTR (water vapor transmission rate) is the steady state rate at which water vapor permeates through a film at specified conditions of temperature and relative humidity. Values are expressed in g/100 in2/24 hr in US standard units and g/m2/24 hr in metric (or SI) units.

This info is not usually published by tubing manufacturers, and only available upon request. We spent close to year gathering the data, to come up with the tubing that had the lowest permeation rate for low maintenance (no refills) applications, and came up with another StGobain product called Norprene, which is used in our Quiet Power P180 chassis.

I am the one who mentionned permeation issues to Stew (Cathar) because this type of tubing doesn't work properly with push-in fittings. Given that we are actively working on reducing maintenance (among other things), use of low permeation tubing is therefore critical to us.

[ranker]

Definition:
ASTM D570-98(2005)
Title: Standard Test Method for Water Absorption of Plastics
This test method covers the determination of the relative rate of absorption of water by plastics when immersed. This test method is intended to apply to the testing of all types of plastics, including cast, hot-molded, and cold-molded resinous products, and both homogeneous and laminated plastics in rod and tube form and in sheets 0.13 mm [0.005 in.] or greater in thickness

Water Absorbtion rate is NOT the information you are seeking.

Permeation rate is the relevant info, also called the WVTR or Water Vapor Transmission rate, and it is usually measured in Grams per mil thickness per 100 sq inches per 24 hours at 73F, 50% relative humidity.

Definition:
WVTR (water vapor transmission rate) is the steady state rate at which water vapor permeates through a film at specified conditions of temperature and relative humidity. Values are expressed in g/100 in2/24 hr in US standard units and g/m2/24 hr in metric (or SI) units.

This info is not usually published by tubing manufacturers, and only available upon request. We spent close to year gathering the data, to come up with the tubing that had the lowest permeation rate for low maintenance (no refills) applications, and came up with another StGobain product called Norprene, which is used in our Quiet Power P180 chassis.

I am the one who mentionned permeation issues to Stew (Cathar) because this type of tubing doesn't work properly with push-in fittings. Given that we are actively working on reducing maintenance (among other things), use of low permeation tubing is therefore critical to us.

Hey Gabe,

Would you happen to know the permeation rate of the more popular brands of Tygon or have a link handy?

[_G_]

So let me be clear one more time (OK call me senile): Push-ins are not designed for low pressure environments. If you use them, be prepared to watch fluid levels often.

BTW Happy Father's Day to all the Dad's in this forum..

when you mention low pressure does that include the vacuum that forms on the suction side of a powerful pump?

[gabe]

when you mention low pressure does that include the vacuum that forms on the suction side of a powerful pump?

excellent observation, yes it does. this is were vinyl tubing will want to collapse over time unless it is reinforced.

[gabe]

Hey Gabe,

Would you happen to know the permeation rate of the more popular brands of Tygon or have a link handy?

As I mentionned above, this data is not published by manufacturers, and you need direct access to factory engineers to get it.

According to the data we have gathered here, PVC formulations (without liners) are at an average WVTR of 5~6 times that of Norprene which is given for 0.83 g mil/100in^2 day, and silicon formulations (without liners) are up to 20x.

[ranker]

As I mentionned above, this data is not published by manufacturers, and you need direct access to factory engineers to get it.

According to the data we have gathered here, PVC formulations (without liners) are at an average WVTR of 5~6 times that of Norprene which is given for 0.83 g mil/100in^2 day, and silicon formulations (without liners) are up to 20x.

Thanks for the response. I'm assuming that St. G won't be answering any emails directly to an end user about this so the info is definitely appreciated.

What are some of the commercial names of the Noprene tubing you've talked about and most importantly does mcmaster carry them?

[C'DaleRider]

Gabe, the water absorption rates I posted for the various Tygon tubing were done by this standard, according to their .pdf files of the various tubings I listed from Saint-Gobain's website:

ATSM D570 for the Tygon Silver, Tygon B-44-4X, Tygon F-4040

ATSM D570-81 for the Tygon LFL,

ATSM D570-98 for the Tygon R3603


So, I think the water absorption, as Saint-Gobain put it in their .pdf's, is indeed the same values you want to know as the permeation rate, or the Water Vapor Transmission Rate......

Now, I do not know what the difference between just ATSM D570, D570-81, and D570-98 are.....maybe you could fill us in?

You mention vacuum resistance......the same .pdf's, again available on Saint-Gobain's website in each tubing's description page, lists these properties for different tubing....


Tygon R-3603....... in 3/8" ID X 5/8" OD..... 29.9" of mercury at 73F.

Smaller tube thicknesses in the 3/8" ID range are lower.




Tygon R-3603 with 7/16" ID X 5/8" OD ...... 15" of mercury at 73F.

7/16" X 11/16" OD ........... 28" of mercury at 73F.



Tygon R-3603 with 1/2" ID X 5/8" OD ..... 5" of mercury at 73F.

1/2" ID X 3/4" OD ...... 21" of mercury at 73F.




Link to Tygon R-3603 specs webpage w/.pdf link for testing specs, measurements, etc.

Link to webpage of all Tygon tubing....lots of interesting variations in Tygon.

[C'DaleRider]

As I mentionned above, this data is not published by manufacturers, and you need direct access to factory engineers to get it.

According to the data we have gathered here, PVC formulations (without liners) are at an average WVTR of 5~6 times that of Norprene which is given for 0.83 g mil/100in^2 day, and silicon formulations (without liners) are up to 20x.

Actually, if you follow the link in my above posting, the link has a .pdf file you can access that lists exactly the ATSM testing procedure for water permeation (ATSM D570-98 for Tygon R-3603) and value within it. So, while you may not be able to get a response from Saint-Gobain, the info is on their website.

[Top Nurse]

excellent observation, yes it does. this is were vinyl tubing will want to collapse over time unless it is reinforced.

So why not use the tubing that push-fits were designed for and eliminate this whole problem?

[gabe]

So, I think the water absorption, as Saint-Gobain put it in their .pdf's, is indeed the same values you want to know as the permeation rate, or the Water Vapor Transmission Rate......

sorry C'Dale but I have no time to discuss this right now. you are incorrect.

[gabe]

So why not use the tubing that push-fits were designed for and eliminate this whole problem?

polyethylene tubing. .. low bend radius .. hard to work with.

[C'DaleRider]

sorry C'Dale but I have no time to discuss this right now. you are incorrect.

DUH...I finally reread and realize my mistake. Sorry.

[ranker]

polyethylene tubing. .. low bend radius .. hard to work with.

Seems like a no sure fire win, instead its just different trade offs, for push fits then. I'll be sticking with barbs rather than having to eyeball my water levels consistently.

Thanks for the heads up Gabe.

[Top Nurse]

polyethylene tubing. .. low bend radius .. hard to work with.

I think I'm using polyurethane and it's easy to work with in the sizes I've used (6 x 8 and 8 x 10). They also have fittings available in 45's and 90's if you want to do something peculiar. For instance this would be impossible to do without 90's:

[ranker]

I think I'm using polyurethane and it's easy to work with in the sizes I've used (6 x 8 and 8 x 10). They also have fittings available in 45's and 90's if you want to do something peculiar. For instance this would be impossible to do without 90's:

It's at that tubing size that most of us are unwilling to go down to, nor take the hit of adding multiple 90's and 45's to our loops, just for the sole reason of saying you can make it work.

You've made it clear that top notch performance isn't what you're after. I believe Gabe is expressing how it wouldn't be ideal for for the medium/high flow builds. The tubing required for optimal 3/8", 7/16", 1/2" wc'ing builds seems to be too stiff with an atrocious bend radius.

[SiGfever]

The idea was very appealing but it seems that the trade off of convenience to leak rate does not warrant their use.

[_G_]

maybe what is needed is a normal 7/16 barb with a 3/8 id.
Anyone in here have a CNC screw machine laying around?

[dinos22]

i like your setup Top Nurse

[Cathar]

I'm just feeling that this is all excellent discussion. I can provide the feedback and the theory to demonstrate what the effects are, and it's put it to the wider community to come up with a practical solution to make it all possible. I put forward the idea of push-fits, but it seems that there are issues here that I wasn't aware of. I don't have all the answers and haven't tested everything, yet here we see a wide selection of forum users who were once at each other's throats, combining experience and working together to find a way to arrive at a practical deployable solution.

Really good stuff guys! Keep it up!

[Top Nurse]

maybe what is needed is a normal 7/16 barb with a 3/8 id.
Anyone in here have a CNC screw machine laying around?

You can make simple barbs like this with just a regular screw machine. No CNC needed. Of course you have setup charges to assimilate into the price, but a 500 piece run would certainly be possible.

i like your setup Top Nurse

Thanks The fun is in building them.

[GrimReaperGuy]

Gabe, how does Norprene handle compared to the usual Tygon 3603 we play with? It is less prone to collapsing?

[gabe]

I think I'm using polyurethane and it's easy to work with in the sizes I've used (6 x 8 and 8 x 10).

that will work to (all hard tubes will work), but again, hard to bend.

[gabe]

Gabe, how does Norprene handle compared to the usual Tygon 3603 we play with? It is less prone to collapsing?

we strictly use it in conjunction with smartcoils. it cannot be used alone, as it collapse too easily.

in such configuration, we have excellent bending radius, better than vinyl I'd say.. the only problem of Norprene is that it costs 10x vinyl.

http://www.swiftech.com/assets/image...i-parallel.jpg

but in my book, peace of mind primes. by the way, we have performed tests on this over extended periods of time: two exact same loops, one with vinyl, and one with norprene running side by side for 10 months now. results validate the specification data. I have upgraded all my systems to Norprene now, servers, etc...

no one probably noticed (or added 2+2) but that's the reason why we claim such low maintenance in the Quiet P180 ;-)

[DarthBeavis]

my wife says small tubing works well but she won't admit she like bigger better cause she knows it just is not available