Reducing water deposits and build-up

[falakeh]

Are there any recommanded coating or surface treatments for stainless steel pipes that will reduce likeliness of mineral deposits and limescale build-up? Frequent cleaning, flushing, etc, is costly and time consuming. I am looking for possibly a low-friction inert coating that reduces the chance of build-up on the ID of a fine-mesh heat-exchanger pipes.

 

[bimr]

No. What you need to investigate is water treatment to prevent the water from scaling.

 

[Montemayor]

An engineer does not recommend a "magical" coating that will erradicate lime and calcium deposits on pipes. An engineer does what Bimr is inferring: Cure the cause and don't chase the effect.

Magical coatings, like snake oil, are a "filament" of a con artist's imagination. They don't work because they don't exist. What does exist (& works) is good water quality control.

 

[falakeh]

Use of specific detergents to reduce water spots on glass in dishwashers vs. a water distillation and/or filtration system. Which one do you think is cheaper and more prevalent?

How about Parylene coating?

This is not for high volume plumbing system, but a heat exchanger for a small home appliance using drinking water. Asking consumers to install filtration or reverse osmosis system just to be able to use our product is out of question...

Low friction or corrosion resistance coatings are not magic. So why not scale-resistant coating? RainX?

 

[TBP]

I can just feel the "disturbance in the force" from all of the magetic water conditioning guys wanting to post

Pretty much, if you need or want soft water, you'll need to install a water softener.

 

[falakeh]

Do not want softwater...Want mechanisim robust enough to work with hardest water allowable for use as drinking water in US. We are not drinking the water. Just using to transfer energy....

 

[rconner]

falakeh,
I certainly understand what you "want" (and agree this is certainly a very impressive pure research objective). While not familiar with your application, I am aware that many others in the past have also wanted this for various services, apparently even to the point of believing/buying claims of various plastics and/or polymeric pipes that scales or films etc. don't form/collect on their pipe surface. Unfortunately, there have been at least some cases where in spite of the claims and perceptions the pipes they bought based on such perceptions have still had (flow restricted by etc.) formation of films and/or scales (I am aware of some problems myself, of scales forming in polymeric/plastic pipes, at least up to 60" size! in various services). I suspect similar experience is guiding some of the other responses you are getting on this thread. I'm not sure the chemistry and equilibrium (or lack thereof?) conditions that result in some scale formations pays much attention to at least common surfaces!

 

[TBP]

Water softeners are commonly used in large industrial applications, like make-up water for steam boilers. The aim is to keep the boiler tubes free from scale, so as not to retard heat transfer. It doesn't matter whether you're drinking the water or not. I can think of one area not far from me where the well water routinely runs 600-800 PPM hardness. Without water softeners, things like residential domestic water heaters will typically last only a few months.

 

[mshimko]

Most "magic" coatings, when tested in a reproducable manner, are revealed to be worthless - and this is on surfaces which support proper surface preparation and application. This includes so-called low-energy and/or easy-release coatings.

Now try to apply a coating to the inside of piping, where surface preparation & application are difficult - and I'm doubly skeptical.

Last - consider the durability of the coatings. Yes there are coatings sufficiently durable, but they are not low-friction and reduce heat transfer, which I assume is not something desireable in a heat exchanger.

 

[Montemayor]

With all this empirical, field experience, and practical logic you would think an engineer would cease looking for the magic coating that has eluded all the rest of engineering through the centuries. I'm coming in with 45 years as a professional engineer and I'll bet if we add to that Bimr, TBP, rconner, and Mshimko's years of experience we could come up with over 100 years of experience backing up the knowledge that we've tried to pass on.

However, some naive people will persist in believing in Alchemy. Just because they don't receive the advice they prefer, they refuse to accept the truth and insist that they are right in their pursuit. Why ask for help if you're not going to accept it or even say "thank you"?

This query is like the skit Johnny Carson used to put on with his portrayal of "The Great Karnack". We're given the answer and we're supposed to divine the question.

 

[kenvlach]

It's a good principle to look for possible product improvements. New materials & application methods are always being developed.

Having said that, I concur with the above responses that a coating would only delay the inevitable deposition, and that a thin coating would be necessary for good heat & water flow. But, can anyone guarantee a pore-free, 1-mil internal coating of PVDF or Parylene? Ask Cookson

http://www.scscoatings.com/parylene_services/index.cfm

for a price quote on that. And, note that crevice corrosion of the stainless could occur holes in the coating.

Using (uncoated) electropolished stainless tubing would probably be a practical improvement.

 

[falakeh]

Sorry, but recommanding to every household to buy a water-softner doesn't really help my product sell better. It only helps water softner companies. You all wouldn't be in that business, would you?

As far as accepting what I hear based on somebody elses (I believe biased) opinion without sound reasoning is just not me. I do not believe any engineer would do that.

Fact is that self-lubricating and low-friction coatings exist and have been used for many years in automotive and plastic molding industry with great results. I am life-cycle testing these coatings for my application and will let you know the results.

I however thank you for your opinion, even though sadly it seems a bit tilted towards promoting filteration and water softening systems.

 

[IRstuff]

Perhaps you should look at what they use for coffeemakers?

They have the heat cycles and the drying out that promotes deposits and scaling.

TTFN

 

[falakeh]

Thanks JRstuff...That's a good idea...