TIG Cooling System?

[graham-xrf]

My choice was for a 20-series water cooled torch. I happened to pick the CK20, and I am now considering the cooler.
Checking through the CK20 manual, and searching around, still leaves me in some doubts about typical flow rate, and required pressure.
Throw in the pressure that might break stuff. How much is too much? What happens if the water boils in the torch?

Is a system rated at 1 bar, and capable of about 13 litres/min sufficient? That translates to about 14.5psi and 2.85 gallons/minute.
It's easy to get up high pressure (160psi), but one wants not to blow up the radiator! I just want to discover what is "normal" in this application.

The ready-built cooling system boxes seem way too expensive for what they are, and I see it as perfectly reasonable to "roll yer own", and come up with something safe, quiet, and functional. I have built cooling systems before (for vacuum furnaces), but of course, they were much bigger!

 

[Nutfarmer]

I use standard house water pressure and move the discharge hose around to water the yard. Can't be any cheaper and doesn't waste water. Never have had problems with over heating. Operating pressure is 35 to 45 psi.

 

[DavidR8]

Were it me (and it might be in the future, I'd hook up an aquarium pump in a 5 gal pail of water and let it recirculate. It would take a long time to raise that volume of water temp a significant amount.

 

[Weldingrod1]

The worst case heating is DC reverse polarity, where 70% of the output power goes into the electrode. I'd be really surprised if you have more than 7 kW output, so worst-worst cooling is 5 kW. 0.15 gpm will take water from 70 F to 200F. So, the water flow for a total loss system is tiny! I used a postal van heater core for my first cooler, with a 4" muffin fan on it. You plumb the cooler outlet directly to the reservoir. At 1
2 gpm you will get a 40 degree temperature rise, worst case. So, again, you don't need a big circulator. I used a carbonater pump I had laying around.

Calculators - White Knight Fluid Handling

wkfluidhandling.com

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[jwmelvin]

Though the flow rate is pretty low, it seems like people use fairly high pressure pumps like carbonator pumps, as the loop has a lot of restriction. I can’t be of much help as I bought a used TIG rig with a cooler.

 

[graham-xrf]

Thanks much for the replies.
@Nutfarmer - The pressure information is useful to know. I get it that one can go welding, and re-use the water, but I will not be doing that. TIG cooling systems use recirculating distilled water for a reason. Most include anti-corrosiion additives. Some use glycol (or other) non-aqueus fluids as used in certain cars. At least now I know that 30psi is not outrageous. I was considering a re-purposed little oil cooler radiator. Something a bit more than a water-cooled PC might have.

I am not sure of the galvanic insulation from water, through brass parts, to a DC electrode, but my instinct says do not put chlorine conductive water into a cooling system. When one has to pump cooling water into induction heaters, the water is non-conductive (distilled). The arrangements are elaborate, and expensive, and would not have been done if it was as easy as connecting a domestic tap hose.

@DavidR8 : We think alike, but take care. We are talking here of water potentially much hotter than what was in the mind of the aquarium pump designer. Most little plastic aquarium pumps might not like it. At least the more robust camping/caravan/boating pumps can handle hot shower water. If as much as a few hundred watts is heating a torch brass internals, sufficient water flow had better be there to remove it, or there will be boiling, and super-heated steam right there in your hand. It does not take much to figure out what happens next.

I think you need enough pressure to guarantee an adequate flow rate through the flow resistance of the pipe lengths. Those bores are small. If you need convincing, try blowing up one - or even just use a drinking straw.

@Weldingrod1 : Thanks so much for the excellent fluid heater calculator, and the reality lesson from real experience about how much cooling fan and water flow is really needed. The thing on the end dissipating heat has a constant in °C per watt, and that sets the temperature rise. If ambient on a hot day gets to about 35°C, and we want to keep the exit from becoming scalding hot, then I would hope to keep the rise to about 20°C.

I have never used a carbonator pump. I don't know what pressure they get to. The only "carbonation" I have ever done was a soft drinks gadget that used a tiny CO2 cylinder about the size of a lipstick cartridge.

[Edit: OK then - maybe a shotgun cartridge! ]

 

[benmychree]

I used a carbonator pump for many years, taking water from a 5 gallon bucket (and returning it for recirculation), it gave no trouble and worked fine for the work that my shop did, mostly welding stainless tube and fittings for winery tools and products.

 

[Weldingrod1]

Carbonator pumps are positive displacement with an integral pressure relief. They are capable of much higher pressure than you need. Constant flow up to popping the relief.

If you are closed loop I would go with either straight glycol or glycol/distilled water. Yes, you want to minimize conductivity. You will have a rubber hose between the pump and the torch lead to provide some isolation.

My gauge was 100 psi, and the actual reading was much lower. I dont remember how much lower, though.

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[G-ManBart]

I have never used a carbonator pump. I don't know what pressure they get to. The only "carbonation" I have ever done was a soft drinks gadget that used a tiny CO2 cylinder about the size of a lipstick cartridge.

I've had my hands on several brands of commercial coolers so far....five different Miller Coolmate and Watermate models, Bernard, Dynaflux and one import brand off the top of my head. All of them used a Procon or Procon style carbonator pump and they typically say to set the relief pressure around 60PSI.

The one thing I'd highly recommend is running at least a mix of commercial TIG coolant with the distilled water. Any time I've had to mess with a cooler that was run with distilled water, tap water, or automotive antifreeze the tank is absolutely disgusting, and often I find the cooler hoses have started to break down as well (mostly with the automotive antifreeze). Commercial coolant is supposed to have a biocide that will help limit the growth of algae so I always run at least 50/50. I'll flush the system with fresh water, then flush with pure distilled water, and finally add a 50/50 mix of low-conductivity coolant and distilled water. If you replace the coolant every year or two you should never have an issue.

 

[G-ManBart]

Carbonator pumps are positive displacement with an integral pressure relief. They are capable of much higher pressure than you need. Constant flow up to popping the relief.

If you are closed loop I would go with either straight glycol or glycol/distilled water. Yes, you want to minimize conductivity. You will have a rubber hose between the pump and the torch lead to provide some isolation.

My gauge was 100 psi, and the actual reading was much lower. I dont remember how much lower, though.

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Miller lists 60PSI on several of their models with Procon pumps, and I suspect that's pretty standard since most seem to use the same basic pump setup.

I found a workaround once when I didn't have the right fittings to put a gauge on a cooler after reassembling the pump and it seemed to work well. I've flushed and then tested quite a few coolers now, and after I've flushed the system completely I like to fill it with fresh water, hook up a 5-6' output line and check the flow before adding coolant. I've found that they typically send the water 10-15' with the hose held just above horizontal. When I reassembled the pump I adjusted the relief valve until it sent the water 10-15' and it's been fine every since.