glycol leak in closed-loop cooling system
glycol leak in closed-loop cooling system
(OP)
Hi All
I'm investigating a slow but continuous leak (~5ml in 3 days) in a closed loop cooling system. The working fluid is polypropylene glycol.
There are no visible leaks, so I'm wondering if the coolant could be diffusing/evaporating through tubing elements which are all plastic. Some literature also seemed to suggest that glycol could react with some plastics and be absorbed by them.
Has anyone encountered a similar problem? I'd appreciate any direction to concentrate my efforts.
Thank you
I'm investigating a slow but continuous leak (~5ml in 3 days) in a closed loop cooling system. The working fluid is polypropylene glycol.
There are no visible leaks, so I'm wondering if the coolant could be diffusing/evaporating through tubing elements which are all plastic. Some literature also seemed to suggest that glycol could react with some plastics and be absorbed by them.
Has anyone encountered a similar problem? I'd appreciate any direction to concentrate my efforts.
Thank you





RE: glycol leak in closed-loop cooling system
TTFN
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RE: glycol leak in closed-loop cooling system
RE: glycol leak in closed-loop cooling system
RE: glycol leak in closed-loop cooling system
RE: glycol leak in closed-loop cooling system
Since this is an ongoing problem, you can rule out the plumbing, since it should either be saturated in absorption, and/or you'd be seeing glycol residue on the exterior of the hoses.
Of course, things are rarely truly "closed loop", since you need something to allow for thermal expansion.
What temperature range is the coolant exposed to?
How do you handle the boiloff, if any?
TTFN
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RE: glycol leak in closed-loop cooling system
Yes it would empty out if no one refills the system, but it hasn't been allowed to do so.
The tank isn't filled to the brim, which is supposed to account for the thermal expansion I think.
The system operates fairly tightly around 50C. I'm told the glycol content is there for antibacterial measures.
Would it be possible for small quantities of coolant to diffuse through the hoses and evaporate before detection? What would glycol resudue look like? I have seen some small white dots on the tubes, but was associating those with spills since they are close to hose ends. Maybe I will clean them up and see if they reappear.
thanks for your help
RE: glycol leak in closed-loop cooling system
TTFN
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RE: glycol leak in closed-loop cooling system
50°C is quite warm, and if the solution is mostly water, you could lose quite a bit through evaporation.
TTFN
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RE: glycol leak in closed-loop cooling system
tests I'm running indicate that there is significant coolant loss through polyurathane tubing we have. In comparison, FEP tubing seems have no loss in the same arrangement.
RE: glycol leak in closed-loop cooling system
Is it oxygen barrier tube?
Oxygen will permeate through the walls of non-barrier tube. The dissolved oxygen will react with hot glycol, producing acidic compounds. I don't know how hot it has to be, whether this would account for the loss of the liquid or what the products of the reaction are. The glycol manufacturers may be able to advise you. Glycol car coolant/antifreeze (usually ethylene glycol) should be changed every few years for this reason. The hoses allow the passage of some O2 and once the soluton becomes acidic, galvanic corrosion of the engine parts becomes very rapid.
A pH test might indicate whether there is problem.
FEP?