Printable View
Dear All,
Question?
Is there another reason other than oxidation (rusting) of the piping internally and externally why ordinary steel (not stainless steel) is not used on Compressor rack piping operating on R22 refrigerant?
Steel pipe is a lot cheaper than Copper pipe, so why don't all the Compressor rack manufacturers use ordinary steel piping to keep costs down?
How about impurities from the manufacturing process.
Hi Emmett,
Do you mean impurities in the manufacturing process of the steel pipe itself or in the process of manufacturing the Compressor rack?
Frigrite in Australia used to manufacture racks with steel discharge headers up to the oil sep, they were a pain in the arse for comp changes as there was no flex in the piping to get 4 cylinder compressors out from under the piping. Bitzer manufacture racks in Australia with steel suction headers for R134a operation to comply with Australian standards. A lot of subcritical Co2 racks are built in steel and obviously b nearly all of transcritical ones.
Hi 750 Valve,Quote:
Originally Posted by 750 Valve
Thanks for your input.
I have seen many different compressor racks/Packs with partial steel piping used as you mention in your post.
Still, I have come across 2 Compressor racks (1 LT and 1 MT) operating on R22 refrigerant and ALL the piping is steel, suction and discharge piping/headers etc etc, not 1 piece of copper piping is to be seen anywhere?
(These racks are approx 6 years old).
It just got me thinking why do compressor rack manufacturers use copper if it so expensive instead of steel and there is no technical reason not to use steel?
Surely if they used steel they would have a competitive edge on pricing?
I was hoping someone on RE forums may have a technical answer for not using steel piping with R22 refrigerant compressor racks?
I love your avatar (-:
best regards
Buddy.
Yes, Cooper is a lot of expensive, specially for big diameters.Quote:
Originally Posted by buddy
Cooper pipes are better to make the pipelines, because welds are easier and cleaner (good for the internal circuit)...so you shall count with a reduction on the connection mounting hours (less labor).
Also lower tendency for corrosion » less leaks.
Don't need to paint the cooper pipe.
Yes the steel pipe itself. also I agree with sandro, it does seem tha the labor to install threaded pipe vs copper would be incresed a great deal.Quote:
Originally Posted by buddy
Hi Emmett,Quote:
Originally Posted by Emmett
Your point would stand up regarding labour costs in Western Country's with high labour costs.
However plenty of compressor packs/racks are manufactured in low labour cost country,s such as China, Linde (Carrier), Heatcraft, Hussmann etc all manufacture compressor racks in China, but they all still use copper piping which is very expensive even in China in comparison to steel.
So sorry I don't see the validity of labour costs being the issue for preventing steel being used on all compressor rack piping?
Is it just a historical thing that, that's the way they have always manufactured compressor pack piping in copper?
I,d love someone to come up with a technical reason for not using steel piping.
best regards
Quote:
Originally Posted by buddy
Still cooper advantages:
cleaner (good for the internal circuit)
Also lower tendency for corrosion » less leaks.
Don't need to paint the cooper pipe.
It's a production criterion
The % increase of the rack maybe have no significant meaning
Attachment 7245Attachment 7244as you can see this is rust residue taken from a linde pack, as the receiver sits on an angle the liquid never sat in the top of the receiver and through time the inside of the steel receiver become rusty as hell which eventually saw the plant being repalced, linde reported back that the moisture/water in the system attacked all the welds used on the receiver which spread into the rest of the steel, so i suppose steel isnt that great!
Profroid Packs used steel Headers, and there was an issue with Refrigerant leaks.Quote:
Originally Posted by buddy
(Not sure if they still use them)
Thanks Coolhibby1875 for the photos and information.
Have you any more?
Hi Mark,
Just wondering that refrigerant leaks and rust seems to coming up as the 2 common reasons why steel piping is not used on Supermarket Compressor racks instead of copper piping.
As regards leaks through steel piping is that maybe because it is more porous than copper or just bad welding (jointing) that Profroid stopped using steel?
Hi BuddyQuote:
Originally Posted by buddy
All metals in solid form are considered pourus but not to the melecular level that a refrigerant pass's through them... liquid metals are not porous ie: mecury, but obviously they have no structual strength,
R's chillerman
Hi Chillerman2006,
Yes I should have put porous because of the leaks caused by steel rusting and not porous at the molecular level.
Thanks for pointing it out.
best regards
Hi Buddy
I should have realised what you meant mate ... was in a rush this morning ... got up late .. logged in for a quick browse & then made later still !
R's chillerman
Ha Ha, Its OK, been there done that many times myself.Quote:
Originally Posted by chillerman2006
best regards
So folks it looks like from comments on the thread, the only reason is that steel piping is not used on Supermarket Compressor racks is because steels rusts if moisture gets inside the refrigeration system.
Is that the only reason?
best regards.
Hi Buddy
generally steel pipe is factory fitted with a mill scale residue and surface rust even if capped that has to be removed, here steel welding by regulation is by certified welders, cutting and grinding and welding adds more gunge to system. With R22, a really good flushing cleaning refrigerant all the crap ends up back at compressors and suction strainers etc., commissioning is a big drama getting systems clean. Stainless steel less of a problem, copper better again if done properly with nitrogen purging.
Even on the outside surface corrosion tends to appear. On the cold lines if the insulation it's not done properly, past some years leaks stars to appears...unless you use a very tick wall :)Quote:
Originally Posted by buddy
I meant thick wall not tick wall
Thanks every body for your input.
So in conclusion to my question it looks like the majority of you say corrosion is the no1 reason for compressor rack manufacturers not using steel piping on compressor racks.
best regards
One reason assigned is the loss of ductility of ordinary steel ( mild steel) at lower temperatures
below (-40) deg c ..........
Hi D.D,
Yes I understand the ductility issue at low temperatures but the lowest evap temp I have come across for Supermarket application is for Island freezer system at -35 degrees C so that would not be a problem?I
would you not also have the battery principal as well copper steel and a acidic liquid = slight voltage :) just a thought :)