Spunding Valve - Commericial Style DIY

Hello All,

I am a "Spunder" and have quickly come to realize the need for some kind of feedback about the pressure being released so you don't under or overshoot target pressure. When doing it with an ordinary pressure relief valve I have never been able to dial in the proper release of pressure to maintain a certain tank pressure because usually it is such a small crack of the pressure valve that is barely audible.

So I have taken inspiration from commercial spunding valve and an idea from Bobby and come up with this:


photo by brewerJP

Note that the PVC cap is a temporary cap while I test the valve - will be the stainless cap you see in the pic below. Here's the exploded view:


photo by brewerJP

And here it is in "action" - input pressure was around 15psi from my air tank:


photo by brewerJP

The idea is pressure is vented against the viton ball. The more pressure you apply to the spring, the less it will let vent. Fill the device with water and you'll see feedback from the release of pressure and you'll have a much better idea of how to adjust the relief. These types of devices are used in many commercial breweries that naturally carbonate at fermentation - which is what I do.

Only problem I'm having at the moment is the spring has a tendency to want to kink. I think this is because the ends really need to be ground and I need to make sure the tap into the cap is perfectly straight. Otherwise - it seems to be dial in really well.

I will post up a parts list after I have the kinks worked out. Just wanted to share it now!

The design concept, if not the appearance, reminds me of the Barby-Kuhner valves I used to use in a few pubs. Well done sir.

That is very much the style of what it is modeled after - so I appreciate that! Those commercial spunding valves are mega-expensive - I've not found them under about $420 bucks and they can be upwards of $800+. That is why I have branched out to see if I could build one.

Yeah so this is totally awesome. Subscribed!

You're very welcome! ... and yes they are! I have rebuilt the things a few times and always wondered WHY they cost so much... At the time I was using them they went for about $350 and rebuilding one would set you back around $200... yet, it was a piece of (albeit heavy) plastic, spring, diaphragm, adjustment screw... small stainless housing with threads for TC ferrule and a pressure gauge. I wish I had ASKED someone at the time why they cost so much LOL Maybe it was an issue of liability? Test, double test, insurance, etc. Obviously IF one failed the results could be potentially be VERY ugly... maybe it was because the Germans making them were paying their people the big bucks... I dunno... Whatever... they WORKED and worked well! Again, let me say, GOOD JOB!

Wow!

I'm ready to build one.

How do you envision calibrating it?

Wow this is cool, all i need to know is where do you get the vitron ball?

Everything came from McMaster... I will post all the part numbers up once I feel comfortable it's good to go! I need to work out the kinking of the spring which I think might be as simple as grinding the ends.

Marquez said:

Wow!

I'm ready to build one.

How do you envision calibrating it?

Click to expand...

Same way you'd do it with the commercial valves - just do it! Let the tank build pressure over target, then slowly release tension on the spring until you hit the target pressure and see no signs of pressure release. It will take some trial and error at first but then it should be golden and you can lock it in place with the jam nut. That's not to say you shouldn't watch it - because any vessel under pressure you should be watching like a newborn.

Subscribed

Fantastic!

I would recommend pressurizing the keg (or other fermentation vessel) manually when you attach the valve. Setting the blowoff point immediately rather than allowing the keg to come up on it's own. The reason being that if you should miss your window things can get ugly. Worse case scenario being someone getting hurt, but even apart from that it can be difficult to establish the equilibrium afterwords... You end up having to blow it down manually, etc. I would further recommend checking it with EVERY use. These things are temperamental and require precise calibration to function properly. Any little knock or bump or flap of a butterfly's wings can change the set point when it is not under pressure.

I know that sounds kind of like I am poo-pooing the thing, PLEASE don't take it that way! I love it! Now, it is true that by adding a little pressure when capping your fermentor that you are going against the rheinheitsgebot, which is surely why you don't see the method I mentioned being championed by German purists, but it really does work better (IMO). The little bit of CO2 that is added is going to be the first to be blown off anyway, so that which is actually carbonating the beer will be entirely or almost entirely from the yeast activity anyway.

Right - that is why I said watch it like a newborn. I would never pressurize anything without watching it at least a couple times a day. Usually you have a few days before you come up to ideal pressure in the fermenter. I don't spund in a keg so I imagine that's probably a different story.

If you're not following the RHGB - then using CO2 is just fine. I am trying to follow it. The new revisions say you're allowed to top off but not use external CO2 for primary carbonation.

Anyone thought of a digitally controllable valve? Cheap? No, but there's got to be something out there that would work. I'm thinking of something on the lines of an Asco solenoid valve that could be monitored and controlled remotely.

You could probably automate it with a digital pressure sensor and a stepper motor controlled by an Arduino. The stepper motor can turn the knob to adjust the pressure. Sounds like a fun project.

You could always install a safety relief valve with a tee. Or you just use the relief valve on the keg but I think they start to vent at about 100 psi. Which at that point the beer would be extremely carbonated and I would think that most of the beer would blow off.

I don't think it would be particularly difficult but I question about how smart it would be. There are some things that probably shouldn't be automated and it's debatable if this is one of them. At least if you're going to do it better put a safety valve somewhere.

jcaudill said:

I don't think it would be particularly difficult but I question about how smart it would be. There are some things that probably shouldn't be automated and it's debatable if this is one of them. At least if you're going to do it better put a safety valve somewhere.

Click to expand...

I was about to say something of this effect. Electronic stuff does fail sometimes, and if it did in a case like this... well, the results could be fatal. No thanks.

With the spunding valve you'd still need to have a regulator for each keg in your set up just to prevent a constant ventilation of CO2 for brews that want lower than your primary regulator is set for, correct?

Or am I not correctly understanding what this is for? Is it used more like an airlock on a carboy?

If you're spunding, your regulator is not hooked up. Fermentation is taking care of co2. The valve is the regulator.

jcaudill said:

If you're spunding, your regulator is not hooked up. Fermentation is taking care of co2. The valve is the regulator.

Click to expand...

Right, about the only time you would connect the gas to the keg would be if you, as I suggested, pressurized the keg manually to calibrate the spundig.

Quick update:

I did a trial run on a 20 BBL fermenter today. For the most part it went pretty darn well! I am going to try a couple of ball, spring, distance combos out though to see what the most predictable setup is. The one thing I noticed today is the viton ball I used tends to want to get stuck in the reducing coupling taper and it takes a certain level of pressure to force it out.

Only other note which I think I mentioned before is this setup really needs a spring that is ground flat. I will be on the hunt.

I'm headed back tomorrow for more trialing.

What is the source and part number for the clear pipe? I'm thinking sight glass for my O2 stone/thermometer assy.

http://www.mcmaster.com/#clear-pvc-pipe-fittings/=hzbrhi

Go to pipe nipples, threaded on both ends.

Today's update: slightly larger ball is better. I drilled another cap to see if the spring will compress a bit straighter without grinding the ends. The valve is going into full testing on the 20BBL fermenter for spunding @ 17 psi. Should know soon how good the spring I chose is.

Quick video (probably need to go to fullscreen)



Demonstrating holding 17psi:


Untitled by brewerJP

So far, so good.

I see a still pic, but no vid. Still, it looks damn cool. You're rocking that thing, my man! You get it dialed in just as you want it and you could have a tidy little side business on your hands!

Odd - does the video work now? I can see it at least.

Thanks!!

Yep, there is now!

Did you every finalize the design? If so, do you have a final parts list available?

Looks like a great design.

Thanks

Not yet - one thing I'm struggling with figuring out is kinking of the spring which in turn producee uneven force on the ball and makes fine adjustments really tough sometimes. I would just increase the spring rating but I'm afraid that will put too much pressure on the ball and jam it. I will have some time in a couple weeks to think this through and provide an update.

This said - it does in principle work fine - just not as solid as I'd prefer.

Do you have the option of using smaller diameter plumbing or perhaps a larger diameter spring with maybe a washer on the end where the viton ball is? The washer having a smaller diameter to keep the ball in place.

how about a "floating" pin inside the spring? not long enough to restrict adjustment but long enough to give the spring support and stop it from kinking.

Definitely some good ideas here! I will investigate both.

You could also try floating tube around the spring as well. Something rigid that keeps the spring straight and just short enough to allow the ball to unseat from the seal. The tube would also need to clear your adjustment screw.

That is a great and simple idea too. I was thinking along a whole different and completely complicated line. I will give these a shot and provide an update soon!

rekoob said:

how about a "floating" pin inside the spring? not long enough to restrict adjustment but long enough to give the spring support and stop it from kinking.

Click to expand...

This is what I was thinking. Like a golf tee cut down to 3/4" and inserted in each end of the spring.


You might be able to find them in a plastic that would be more sanitary/cleanable and cheaper and easier than building or sourcing something else.

Just found this thread and need to know if there are any updates!

Good work sir!

The most important update is that I suck It has been a long 6 months of no brewing trying to get equipment back together. So I haven't been motivated to test the changes on the valve.

The good news is there is enough interest for this as of the past few weeks and I'm about to start brewing again (YES!) so I have to get it straight since spunding is an important part of my process!

Stay subscribed and tuned, I will provide some kind of update!

Great to hear this thread hasn't died, subscribed