Regulators as "Spunding" Valves

I'd hinted at this arrangement in another thread, but might be better if I spawn a new thread to cover it:

foxy said:

Long thread but worth reading.
https://aussiehomebrewer.com/threads/fermenting-under-pressure.66163/page-18#post-1492118

Click to expand...

The AR2000 is a regulator. The AP100 I'm about to use is a pressure relief valve. But regulators can work as pressure relief valves and I wanted to use my favourite regulators at moment, the Shako NR200, but couldn't find what they relieved at or even if they did relieve. "Relieving" regulators can be a nightmare as my experiences with the Shako NUR regulator turned out (very precise PRV though), but the cruder relief mechanism used by many regulators looks just right (cruder, but still more sophisticated than the common "poppet" PRVs). "Relieving" regulators relieve pressure through the body, not the other port which for regulators is being used for high pressure in (10-16BAR max, these are "secondary" regulators I'm talking about, i.e. not connected directly to the CO2 bottle). The handy thing about using "relieving" regulators is they can have a gauge fitted directly to them instead of "tee-ed off" like the usual spunding valve design, and it is in place as a regulator when its done being a spunding valve. The NR200 (and AP100) are diaphragm type designs, much more precise than the common spring and plunger types.

The disadvantage I found with using regulators like this is many are apt to vent all pressure from the low pressure side when the high pressure side has no pressure. Needs a bit of working round.

I'd really like to hear from others who have dabbled with this type of arrangement.

Yes, the poppet valves aren't very good. I've been meaning to swap mine for a while. A popular choice I've seen on American forums is the Airtrol RV5300 relief valve, although I've not seen any regulators being used.

"Inspiration is the impact of a fact on a well-prepared mind" Louis Pasteur

I haven't carried over the reason for exploring "alternative" means of relieving pressure:

"Poppet" valves might be okay at opening at the set pressure, but are notorious at reseating (closing) reliably. Hence they are used as emergency relief devices and not very suitable as accurate pressure control devices (which is what home-brewers are forcing them to do when using them in "spunding" valves).

Sadfield said:

Yes, the poppet valves aren't very good. I've been meaning to swap mine for a while. A popular choice I've seen on American forums is the Airtrol RV5300 relief valve, although I've not seen any regulators being used.

Click to expand...

Can't find any of those RV5300s over here (at a reasonable price). The AP100 are more available but I've yet to try the things (in the next week or so - I'll keep you posted).

I'll try and get those Shako NR200 regulators sorted out soon too - they cost less than 10 quid (with gauge) and can be sourced in UK. I'm positive they do relieve, but I don't know how accurate they'll be.

Peebee there is one ( relief valve ) on Amazon and USA ebay looks like it might do the job well, its incremented much like a micrometer so you can just dial up the pressure you want.
I would be interested to see what you can come up with, the quality of the gauge and especially the reief valve is impotant.

foxy said:

Peebee there is one ( relief valve ) on Amazon and USA ebay looks like it might do the job well, its incremented much like a micrometer so you can just dial up the pressure you want.
I would be interested to see what you can come up with, the quality of the gauge and especially the relief valve is important.

Click to expand...

I know the ones! They are the "poppet" type design and it was the bad reports of them that lead me to looking for alternatives.

I wasn't too worried by criticism of the inaccurate graduations - as long as they are read as a guide for that particular valve and not as a calibrated PSI setting. Treated as a guide the graduations are better than is usually offered. But they are also criticised for reseating badly after being triggered.

I'll keep working on these diaphragm devices as perhaps being a better solution.

I feel I should explain why diaphragm devices are better than poppet devices.

A poppet is just a plug held in place by a spring. When the pressure gets too much for the spring to hold the poppet in place the poppet lifts and the pressure is vented until the spring can close the poppet again. The spring pressure is adjustable.

A diaphragm device also has a poppet holding back the pressure (confusion all round)! But the poppet is connected to the diaphragm and the spring applies to the diaphragm. Now the poppet lifts when pressure causes the diaphragm to bulge. The pressure applies its force to a much larger area which means the system is far more sensitive to changes.

A diagram explains this better (note "in" and "out" swap places in this diagram, because in the first the poppet is pushed off its seat and in the second, the diaphragm design, the poppet is pulled off its seat):

I have been trying to source a good (better than the standard poppet) pressure relief regulator for spunding just like the ones you do see in the US.

If anyone is able to source one please do post it on here.


Sent from my iPad using Tapatalk

Hoddy said:

I have been trying to source a good (better than the standard poppet) pressure relief regulator for spunding just like the ones you do see in the US. ...

Click to expand...

You've not been listening to what I've been saying! Those US ones are not better, in fact they get worse reviews than some others. I'm trying to figure out far better alternatives in this thread, that are also available direct in the UK and cheaper than those "US" ones.

This is the naff one I think you refer to:

peebee said:

You've not been listening to what I've been saying! Those US ones are not better, in fact they get worse reviews than some others. I'm trying to figure out far better alternatives in this thread, that are also available direct in the UK and cheaper than those "US" ones.



This is the naff one I think you refer to:

Click to expand...

Yeah and that’s me not being clear. I meant one that “looks” like it, but as you say works better. And available in the uk.....


Sent from my iPad using Tapatalk

These are the ones I have. Can't see the above pic to see if it is the same.

I need another and I have been thinking of this one.
https://au.rs-online.com/web/p/pneumatic-pressure-relief-valve-function-fittings/3989114/

foxy said:

These are the ones I have. Can't see the above pic to see if it is the same. ...<cut>
...I need another and I have been thinking of this one.
https://au.rs-online.com/web/p/pneumatic-pressure-relief-valve-function-fittings/3989114/

Click to expand...

Yeap, they're the ones (and don't seem very good based on the reviews I've read).

The Norgen models I've seen (RS in UK) and seem to be a good choice (it has the same body as their regulators, are a diaphragm design, and presumably you can connect a gauge directly to it). But they are terribly expensive.

The SMC AP100s look good, are still quite expensive, but can be picked up cheap on EBay. I've got two ready to go but haven't got around to actually using them yet. I've also got two Shako NR200L2-02 regulators which I've been able to confirm are "relieving", but I've yet to try them in a "spunding" setup.

All I have found is that they are not as on calibration, about 10 psi off but as long as you take that into consideration they are OK, its good to know where the valve is set, though I suppose the Norgren one could be marked.

Hi!

peebee said:

I've also got two Shako NR200L2-02 regulators which I've been able to confirm are "relieving", but I've yet to try them in a "spunding" setup.

Click to expand...

I've got a spare secondary regulator - this is the model.

I would appreciate any advice on how to set it up as a spunding valve (if, indeed, that is possible).
I want to try fermenting under pressure in a 20 litre plastic jerry can.

Bigcol49 said:

Hi!

I've got a spare secondary regulator - this is the model.
View attachment 12217
I would appreciate any advice on how to set it up as a spunding valve (if, indeed, that is possible).
...

Click to expand...

I'm not sure about that model, but most regulators (certainly not LPG ones) have a relieving mechanism but you might never find out how accurate the relieving mechanism is without testing for yourself. At least your regulator looks as if it is a diaphragm model. This is how far I am with the NR200s:



They are fitted exactly as if using as a regulator. I suspect the "relieving" mechanism will activate (vent over-pressure) at a rough percentage past what the regulator is set to. So (for example) if the regulator is set at 5PSI and vents (relieves) at 10% over-pressure, it'll act as a "spunding" valve set to 5-1/2PSI. I'm counting on the valve reliably "reseating" (closing) before pressure drops back to 5PSI - this predictability is what the commonly used "poppet" type valves fail to do.

The "NUR" regulator models are very good at this, venting just a fraction of a percent over-pressure. But they have other issues that make them impossible to use as "spunding" valves (and as regulators unless very careful!).

The issue to watch out for is if there is no pressure on the high pressure side, ALL the pressure on the low pressure side (keg, or in this case fermenter) is vented!

Note I'm using 6MM/4MM gas tubing and some very snazzy fittings from the pneumatics world, including the regulator. Expensive? There's about £20 worth on view there. The "made for purpose" pub stuff, now that IS expensive (and nowhere near as snazzy).

No guarantees yet that I'm not going to be disappointed.

To test if a regulator will relieve, wind down the pressure adjuster (or you'll end up fainting!), cover any ports up with fingers except the outlet port, blow into the outlet port. You should hear you breath escaping into the regulator body.

peebee said:

The issue to watch out for is if there is no pressure on the high pressure side, ALL the pressure on the low pressure side (keg, or in this case fermenter) is vented!

Click to expand...

Hi!
Thanks for the reply. If I have read your post correctly, I connect the fermenting vessel to the outlet port of the regulator; the inlet and pass-through ports need to be closed off to avoid all of the pressure being vented out of the FV. I dial in he pressure that I want to be inside the FV, and if it goes above that the regulator vents excess pressure.
Where does it vent to, seeing that both of the high pressure ports are closed off?

Bigcol49 said:

Hi!
Thanks for the reply. If I have read your post correctly, I connect the fermenting vessel to the outlet port of the regulator; the inlet and pass-through ports need to be closed off to avoid all of the pressure being vented out of the FV. I dial in he pressure that I want to be inside the FV, and if it goes above that the regulator vents excess pressure.
Where does it vent to, seeing that both of the high pressure ports are closed off?

Click to expand...

Vents internally, into the regulator body. There may be an inconspicuous small vent hole in the regulator body somewhere (there's one amongst the threads of the adjuster knob on the NR200s - you can see it in my picture if you look very carefully).

Watch out! You are thinking of closing of all other ports but the outlet port, but this doesn't mean those ports will be pressured. So any pressure on the outlet may still vent. It's a problem I'm still thinking about. But if a CO2 cylinder is attached to the inlet (as it would be if setting up as a regulator) that would solve it, just not very conveniently.

Bigcol49 said:

Hi!

I've got a spare secondary regulator - this is the model.
View attachment 12217
I would appreciate any advice on how to set it up as a spunding valve (if, indeed, that is possible).
I want to try fermenting under pressure in a 20 litre plastic jerry can.

Click to expand...

That valve looks fine as long as you can get a low pressure through it, also Col I did a pressure test on one of my standard fermenters, looks like the one you can buy from Wilco's took it up to 40 psi and you wouldn't be needing anywhere near that, so that could be another option if you are wanting to brew a bigger volume.

peebee said:

I've also got two Shako NR200L2-02 regulators which I've been able to confirm are "relieving", but I've yet to try them in a "spunding" setup.

Click to expand...

Hi!
How are you getting on with the Shako valves? I like the look of them because they are very economical.
Can you cast an eye over my reasoning: If it was used as a "regular" secondary regulator, high pressure coming IN would be restricted to the pressure set by the Shako, i.e. low pressure OUT. As the outflow is usually to a pressure vessel, the system is balanced as long as no beer is drawn from the pressure vessel.
For a pressure relief valve, the pressure coming IN is from the fermenting vessel and the outflow is vented to the atmosphere through an airlock. If the pressure in the fermenting vessel rises above the pressure set by the Shako the outflow port opens until the pressure coming IN reaches the pressure set by the Shako, at which point the outflow port will close.
Have I got it right?