FOB's (foam on beer) detector. Ideas wanted.

[Infidel]

Looking to transfer from keg to keg pushing beer through a 2" diameter stainless tube packed with hops. This would be done at a very slow speed, several hours to transfer 5 gallons to either another 5 gallon keg or a 7 gallon keg. The problem is of course that I would have to sit there and watch it the entire time - and I can't because it will be in a refrigerator in my garage. So what is needed is a FOB similar to what micromatic sells to bars that don't want to waste precious beer. They stop the flow when foam is detected.
Any ideas on how to DIY this?
This isn't a discussion on why would one want to do this. Think of it as a randallizer which doesn't produce any wasted beer - or more accurately similar to how Sierra Nevada does Torpedo. It is how I want to pump some fresh Simcoe aroma into a tasty beverage which will be ready to drink in a week. Beer is currenly not carbonated, well maybe a little from sealing the lid at 40 psi and letting it sit at about 50F for a few weeks.

 

[aspiffymofo]

It might be cheaper not to diy this,
But what I would imagine is some kind of float in a cylinder that is attached to a balanced valve.

Or maybe something with a diaphragm. Where once the flow increases too much then the diaphragm seals.

 

[ChuckO]

If you are going from keg to keg you could use the weight as a determining factor. If you know the tare weight of each keg you could possibly stop the flow when all of the contents weight has been transferred.

 

[Infidel]

No great ideas here but going from a 5 gallon keg to a 7 gallon keg would allow for a little error.

http://www.beveragefactory.com/draftbeer/regulators/detectors/fob_Foam_Detector.shtml is the best price I have found. $10 off coupon popped up when I visited the page - so $51.95 makes it almost worth it. Very different price from memories of when micromatic was selling them for something in the range of $200

It isn't worth the expense to me, might try it in the bathtub. Bring in a comfortable chair, that's too much time on a toilet.

 

[rvklein]

Perlick sells a coupler with a FOB built in that will save alot of $$ as opposed to going with a separate FOB. I've used them for 5 years on my 100' draft lines and they work great.

http://www.beveragefactory.com/draftbeer/couplers/american/perlick_eks_36000f.html

 

[edmondsonm]

If I read this correctly you really don't need any detector, just some patience. As you push beer, carbonated or not, from one closed vessel to another with compressed gas the flow is only going to occur between the vessels when the receiving vessel has lower pressure than the contributing vessel.

The system is self limiting. You can have a Randle like tube in between the two vessels no problem. This can all occur in a fridge unsupervised. With constant CO2 pressure on the contributing (unhopped) vessel just dump some pressure from the receiving vessel via the relief valve and KNOW the the beer is flowing. It will continue to transfer foam or not until the pressures equalize. NO BEER is wasted or lost. Just keep opening that relief valve on the receiving vessel now and then. If you get in a hurry just hold the relief valve open until foam comes out then shut it and let the foam dissipate.

I recommend transferring from liquid post to liquid post if using corney kegs and have all your components cold.

 

[mattd2]

If I read this correctly you really don't need any detector, just some patience. As you push beer, carbonated or not, from one closed vessel to another with compressed gas the flow is only going to occur between the vessels when the receiving vessel has lower pressure than the contributing vessel.

The system is self limiting. You can have a Randle like tube in between the two vessels no problem. This can all occur in a fridge unsupervised. With constant CO2 pressure on the contributing (unhopped) vessel just dump some pressure from the receiving vessel via the relief valve and KNOW the the beer is flowing. It will continue to transfer foam or not until the pressures equalize. NO BEER is wasted or lost. Just keep opening that relief valve on the receiving vessel now and then. If you get in a hurry just hold the relief valve open until foam comes out then shut it and let the foam dissipate.

I recommend transferring from liquid post to liquid post if using corney kegs and have all your components cold.

I think you have not read correctly
The point is he doesn't want to miss when the beer has finished transferring and the gas is pushed through the system which would empty the tank quickly if not stoped (and potentially scrub out all that nice hop aroma that was just put into the beer!)
You could probably fabricate one similar to the DIY commercial Spunding valve.

... ...
So here are parts:

NPT adapter (reducing coupling 1" x 1/2"): McMaster 4464K534
4" clear PVC, 1" NPT: McMaster 4677T33
3/4" Viton rubber ball: McMaster 3645K7
...

You could probably actually get away with just 1 nipple and plug the tee since you don't need to reset it as you'll just disconnect the system when trasnfer is completed (and smaller sized items as well).
1x clear PVC nipples
1x tee
1x reducers
1x ball (as long as it floats in beer)
2x hose barbs

Assemble like below