[Regent]

I'm hoping for a bit of advice from more experienced co2 system builders.

Finding good dual stage regulators here in the UK seems very challenging.
I've been offered two brand new concoa 412 regs as a package deal. For about 85 dollars shipped.

The issue is they have a max outlet pressure of 0 to 250psi. What problems designing the post body system/dangers would this pose if I swap out the low pressure gauges to allow me to dial the working pressure in? I think the main issue is solanoid selection, any suggestions?

The other options are regs like the boc 8500 or something along the lines of these Hi-lo welding regs 0-5 bar. But neither are as good as the 412s.... I guess the other option is to just get a co2 art system but I like building my own stuff and getting higher quality.

What I don't understand is the reason for needing a high pressure solanoid as long as the low pressure side of the regulator is set appropriately?

 

[Bettatail]

250 psi max output is too high, you will have trouble to find a good solenoid that is both low power and high MOPD to lock the gas.
simply chage out a output pressure gauge with a lower range doesn't change anything, you will have the same problem if accidently adjust the output pressure too high, the solenoid can not hold it and a replaced lower pressure gauge will be damaged...

but, if you can find a good solenoid, 250psi max output regulator is ok, and most high precsicion metering valves are ok working under 250 psi.

 

[jeffkrol]

What I don't understand is the reason for needing a high pressure solanoid as long as the low pressure side of the regulator is set appropriately?

first.. may not be too difficult finding a solenoid..

Now finding one may be a task.
Sample model above, different configurations are available.
Listed as a Clippard Distributor:

Home

The West Group specialise in the design, production and supply of miniature fluid control components and service capabilities.

www.westgroup.co.uk

tel. 442392266031 fax. 442392240323

Aston Road 29 GB-Waterlooville Portsmouth Hants PO7 7XJ United Kingdom

Second, unless there is something I'm missing I'm with you..if outlet pressure isn't set high (normal range 5-50psi) I'm not seeing a need for a high pressure solenoid..

Now in outside the box thinking you can always put 2 single stages in series.. you know inlet..outlet, inlet...outlet. to create a 2 stage system.
I see on Amazon UK the beer regulators can go as high as 100 psi so set first reg at max, second at working pressure.
Should be hard plumbed together though .Using hose is a bit problematic but not too bad at 100psi-ish.

Certain Burkert 6013 and 6027 series work as well.
The high pressure ones are generally 24 AC or 230V AC
US versions (110AC) come up short of 250psi by about 1 bar.

https://www.burkert.com/en/Media/plm/DTS/DS/DS6013-Standard-EU-EN.pdf

see catalog page 16.

And this:

2/2-way-solenoid valve, direct acting

132865 - 2/2 - A - normally closed - inlet port 1 (P/NC) | 2,00 mm (5/64 inch) | 0,00 bar - 25,00 bar (25,00 bar) | Brass | Inner thread - G1/8 | 24,00 V - 24,00 V | FKM (Fluor rubber) | -10,00 °C - 100,00 °C | Valve complete

www.burkert.co.uk

note 100% duty cycle i.e continuous rating.
Note of caution, need to carefully parse specs on "parts" dozens of variations..

THAT includes what I post as well.

 

[Regent]

Exactly the people I was hoping would reply!
Thanks for the input.
@Bettatail so the real risk is the solenoid/downstream components getting damaged if the reg was accidentally opened above holding pressure. I assume as @jeffkrol says that risk is mitigated by carefully regulator use?

@jeffkrol thanks for the options, I've fired off some emails, let's see how much the high pressure solanoids cost.

I have also emailed boc to see if I can get a spec sheet for the 8500 reg my guess is it's rebranded, but they're easy to find in the UK...

 

[jeffkrol]

Hard to pass up 2 new concoas at that price.
A bonus would be if the cga fitting was for co2.

Cheapest new retail reg was $200-ish US.
And still needed to swap cga's. Orig is O2.

Curious about the BOC ( division of Linde)
Found an old issue but couldn't get the pdf
Nov 14, 2012 — BOC has identified a potential issue with multistage 8500 & 9500 series regulators purchased ... BOC 8500 INLINE M/S INERT REG (10 BAR)....

So a caution on used

 

[Regent]

I agree, I've been watching for a while, it's really tricky to find good regs here! Most people go co2 art or co2 supermarket.

They're both 412's which look like nice regs model number 4124802-803. I suspect I'd need to change the cga over to co2, I can't tell from the photos, not the end of the world.

I can get the burket solanoids but they draw quite a bit of power though. The high holding pressure mouse looks very nice! Alternatively:Something like this black box

 

[Regent]

@Bettatail @jeffkrol
So I've been in touch with hi lo, a company I mentioned earlier. All they're regs are hand built in the UK and very affordable given they come with appropriate 'plumbing'. They've asked me what would be the idea spec for an aquarium regulator given they usually build welding/ pipeline/medical gas regs?
What sort of things should I be asking for from a spec point of view inside the regulator itself?

 

[jeffkrol]

Hmmmm hard to say. Most CO2 regulators aren't any different than any other.

IF high volume they need to compensate for the cold but not our concern.

Victor, and frankly the only one known to me that does, has a different seat for CO2.
What's the difference is ??

Highest outlet pressure is prob. about 50psi.
A finer graduated guage on the outlet side maybe.

2 stage regulators generally have no safety valves on the outlet side. There are a few exceptions.

Been my windmill for awhile. I add a 50psi-ish relief valve to my regulator builds on the downstream line. Just because I can.
I've only had the hp side seat blow, which has a safety on any good regulator.
Single stages by default have the downstream protection. Only choice

That could be built in on a 2 stage...2 safety's, high and low.

Just thought of one thing .. 1/8 ntp on outlet.
Minor convienience.

 

[Regent]

Thanks, they're able to supply all of the above!

Default diaphragm is NBR with a PCTFE seat.
Cost is about 125 USD. Which seems reasonable for a new two stage.