Low Pressure Regulator advice

[TheSumOfAllBeers]

I am looking to pick up a regulator that can have its output reliably set to very low levels.
Intended applications:
- as a cask breather
- pressurised transfers out of an SS Chronical (< 2 PSI or you can blow the clamps)
- low pressure top up of FV headspace during transfers (to allow packaging over multiple days, and pitching onto uncontaminated yeast cakes)

It would be great if it can do serving dispense too, but I would be happier to get a narrow PSI range product if it can do the above reliably and safely.

Alternatively what tools exist to reliably measure the output pressure of a general purpose (dispense) regulator and confirm that it is within the levels specified above?

[gobuchul]

Although they are not adjustable, I know people have used propane gas regulators for very low pressure applications, such as CO2 fon cornys with a beer engine or cask breathers and they are really cheap.

They operate at about 0.5 psi.

You obviously need to modify so you can connect to a CO2 cylinder. Not sure how exactly that is done?

[jaroporter]

https://gasproducts.co.uk/gas-regulator ... ooder.html

if you want to use as a cask breather though you'll want the fixed 37mbar one

[TheSumOfAllBeers]

I have seen primary / secondary setups where a standard reg takes from the bottle and outputs into a manifold at ~20-30 PSI or so, and other regs step that down further for normal dispense/transfer under pressure/cask breather options.

[MashTim]

if you want to use as a cask breather though you'll want the fixed 37mbar one

That’s interesting and a cheap solution, so all you need to do is set the secondary reg at a pressure higher than 0.037 bar? Set and forget?

Ah I see, does this need a beer engine as the pump, I take it 37mbar won’t push the beer very far (unless it is a short line)?

[jaroporter]

that's it Tim, either pump drawn or gravity poured

[TheSumOfAllBeers]

A small bit of pressure into the cask prevents the loss of condition, as the Hand Pump draws it off. Not exactly CAMRA street legal, but preferable in a HB scenario.

[PeeBee]

if you want to use as a cask breather though you'll want the fixed 37mbar one

That’s interesting and a cheap solution, so all you need to do is set the secondary reg at a pressure higher than 0.037 bar? Set and forget?

Ah I see, does this need a beer engine as the pump, I take it 37mbar won’t push the beer very far (unless it is a short line)?

As Jaroporter later said, 37mbar is for pump or gravity feed. To elaborate on that, 37mbar will not push any beer out of a half empty upright Corny keg. Earlier he linked my favoured LPG regulators too.

Just to correct what you said: The 37mbar LPG regulator used like this is the "secondary reg" - the regulator that feeds it (attached to the gas bottle) is the primary regulator. And many of these LPG regulators can handle an input of 10 bar (check yours firsts!). Most regulators work a little more reliably if fed a good margin over what it is expected to deliver. Most bottle connected (primary) regulators wont set reliably below 0.75 bar anyway. I feed my LPG regulators (and all my secondary regulators) with 3-5bar.

[jaroporter]

i had assumed he did mean the secondary regulator for setting above the 37mbar, so the propane reg is in effect a tertiary. but it's good to clarify 'cause this can suddenly get confusing! both ways obviously are fine.

I feed my LPG regulators (and all my secondary regulators) with 3-5ba

yep same here

[Jocky]

Does a real cask breather only draw in CO2 when there's below atmospheric pressure in the cask?

I could imagine that a cheap low pressure regulator would do the job, but there's the danger that if there's any leak in your system it's going to slowly empty your CO2 tank.

[jaroporter]

believe real cask breathers do work on negative pressure, like a demand valve, but never used one myself jocky.

i may have had that scenario myself actually draining the tank. or it may have just been finished. but it's a problem as soon as you screw the primary regulator to the cylinder rather than specific to that setup.

[PeeBee]

Does a real cask breather only draw in CO2 when there's below atmospheric pressure in the cask?

I could imagine that a cheap low pressure regulator would do the job, but there's the danger that if there's any leak in your system it's going to slowly empty your CO2 tank.

Aye, that's right. Like LPG regulators they have big diaphragms controlling them and making them look like flying-sauces. The only difference between the different flavours (breathers, LPG regulator) is the amount of spring pressure on the diaphragm countering the keg/cask pressure trying to bulge out the diaphragm.

But with breathers, which operate at atmospheric pressure, any leak wont do much at all as the pressure inside will be the same as pressure outside so gas goes no-where (okay, with enough time and changes of atmospheric pressure the tank might empty as the cask breaths CO2 in from the bottle and breaths excess out to the atmosphere, but how many years have you got?).

But with breathers dissolved CO2 in the beer will eventually (a few days) fritter away to about 0.9 volumes (at 14C, CO2 saturation in beer at 0PSI) which even hardened CAMRA following guys will find quite "flat", hence I do not like or recommend breathers for home-brew. I don't care much for the 37mbar LPG regulators for the same reason (some are okay with them, guess it depends on the type of beer too).


Interesting side-line: If using a breather on a full "Corny" keg, the beer you are drinking will have been subject to twice the pressure that a 37mbar LPG regulator applies (hydrostatic pressure, about 70mbar in a "Corny"?) although my brain fuses if it tries to translate this to the amount of CO2 retained. And that pressure will be greater in larger kegs/casks, and much less if using a floating extractor (like "Caskwidge" which I use). But it does illustrate the relative amount of pressure applied by these LPG regulators. A fact worth remembering when trying to confound "CAMRA following" critics about using them (you do need to be confident that their brain fuses before yours does).

[Rhodesy]

I am getting one of these from santa.

I plan to use it for dispensing from a 9L Corny which is mobile. It can fit either the small charges or a sodastream bottle so nice and flexible,

[jaroporter]

useful post peebee. i'll just say though that the 37mbar does retain the cask condition fine. it's been a while since i researched this but isn't it just fractionally higher pressure (i thought this was a good reason for using it in our setups over an actual cask breather)? or maybe i've just never drunk a keg slow enough to notice..

what point are you trying to make in that last paragraph with regards camra cask ale? it sounds interesting, i'm just trying to work out your angle so i can get my head around it!

[PeeBee]

useful post peebee. i'll just say though that the 37mbar does retain the cask condition fine. it's been a while since i researched this but isn't it just fractionally higher pressure (i thought this was a good reason for using it in our setups over an actual cask breather)? or maybe i've just never drunk a keg slow enough to notice.. ...

I reckon the beer is overly flat after two weeks under a 37mbar regulator. They will slow down how fast CO2 will fritter away and what it will retain is okay for some people, perhaps even me for strong dark beers. This was why I introduced the concept of "perceived as flat" into that treatise I'm sure you've read (https://drive.google.com/file/d/0BwzEv5 ... sp=sharing).

... what point are you trying to make in that last paragraph with regards camra cask ale? it sounds interesting, i'm just trying to work out your angle so i can get my head around it!

Only one answer to that:



Seriously, it was just a way of illustrating just how little pressure these LPG regulators produce and how little pressure you need to retain "Real Ale" levels of CO2 condition. I.e. the hydrostatic pressure at the bottom of a full "Corny" keg is about twice as great as the pressure a 37mbar LPG regulator delivers. Put another way, take an LPG regulator on one end of a piece of pipe and you blowing on the other end, and you'd probably win (unless you've been drinking too much of the beer, in which case you've fainted onto the floor).