Cask-conditioned style ale out of a keg/Cornie (the "treatise")

[DocAnna]

Right, not sure that if you find a low pressure spunding valve it will perform as well as you want it to.

The idea was to make a low pressure spunding waive using an inline non return valve - I have a duotight one that has a spring on a piston that is supposed to open to about 1 psi, this could be tweaked to work as a cheap low pressure spunding valve by reducing the pressure reaching it. Either by using a length of narrow tube which causes frictional pressure drop, or an isolation valve that could be part turned on so cause a fitting pressure loss. I may have some spare parts to play with and will see how it turns out.

The opening pressure of the non return valve will be the deciding factor as that will dictate the minimum pressure.

 

[RoomWithABrew]

As mentioned about I think the opening pressure is over 1 psi

 

[peebee]

... This would be using the line to create a pressure drop in much the same way dispensing lines use this for liquids. I've emailed John Guest UK to ask what the cracking/opening pressure of their 3/8 non return valve is and what the manufacturing tolerance is. Providing it is lower than 1.5psi this should work. A reducer stem will add further junctional pressure loss. Alternatively It would also be possible to instead use a shut off valve on 3/8 line with the check valve to create a tunable low pressure spunding valve. The second option appeals most as the opening pressure on the check valve might change with time.

It occurs to me that what you are describing is the "relieving" bit of a "relieving regulator" (most regulators are "relieving" but of variable accuracy). Much like I use my favoured regulators (Shako NR-200) as "spunding" valves. But just as NR200s are good regulating down to about 4-5PSI, they are only good to about 7-8PSI for relieving. NR200s are decidedly at the "low" end of the price scale but should give an idea of what to expect from the really cheap end of the price scale.

Unfortunately, LPG regulators with their large sensitive diaphragms are never of the relieving type (not really a bad thing, you don't want the regulator venting explosive LPG gas!).

I did play with Shako UCR regulators that have very accurate "relieving" mechanisms but achieve it by releasing tiny amounts of pressure in short pulses - not great unless attached to a compressor (they were a pain to make work with a gas cylinder - I had to isolate them when not being used).

These are the problems of working with pressures small enough for the weather (and dust, etc.) to have an impact on! Don't feel smug if something works okay when first set up, keep checking it's okay over several days!


I'm not trying to dissuade playing about to come up with solutions, just flagging issues so you can avoid the time taken to "rediscover" them.

 

[DocAnna]

These are the problems of working with pressures small enough for the weather (and dust, etc.) to have an impact on! Don't feel smug if something works okay when first set up, keep checking it's okay over several days!


I'm not trying to dissuade playing about to come up with solutions, just flagging issues so you can avoid the time taken to "rediscover" them.

Thanks for the caution. I am having a bit of fun thinking of protective measures. I'm thinking a balloon on the open end of the check valve. It would show if there was any pressure being vented, and if there was over pressure due to the valve sticking, the pressure created in the balloon would quickly close the valve. I was working in the hospital last night but should get tonight to see what can be made if I still have the parts ,

 

[DocAnna]

As mentioned about I think the opening pressure is over 1 psi

Ooo ... just had a response from Reliance Worldwide Corporation (RWC) who distribute the JG fittings , with the crack pressure of their 3/8 check valve as 0.02 bar, about 0.3 PSI. No tolerance quoted though. This is a lot lower than the equivalent duofit 1+ psi. This is super encouraging. I think I have a duofit inline check valve already so will try this, but this means the 3/8SCV John Guest Acetal Single Check Valve is definitely on for this!

 

[RoomWithABrew]

Duotight? Or a new brand?

 

[DocAnna]

Duotight? Or a new brand?

oops yes - my mistake not duofit

 

[LeeH]

When I sold cask beer in our restaurant, I found this to be the absolute best way of maintaining real ale quality. RLBS Cask Aspirator / Breather Valve

Easy connection to my keg CO2 secondary gas board.Strangely, my keg beers outsold the cask to a point where it wasn't worth the hassle of even stocking Fyne Ales Avalanche.

That also gave my liver a rest, when not feeling obliged to sup old cask beer or feed it to the compost worms.

20 days seems a short period, did you find it lasted longer?