Campbell, you've made me realize I don't understand my filler nearly as well as I should. You wouldn't happen to remember what other MBAA presentations you look at, would you?
Original Message:
Sent: 07-05-2023 16:58
From: Campbell Morrissy
Subject: Comac 14-2 Canning Line TPO issues
Hey Francesco,
I can't speak to the Comac specifically, but we have found that proper under lid gassing (ULG) set points are one of the main drivers for controlling TPO on our line. For reference we are running a Kosme/Krones 16/4. Our average TPOs are 30-35ppb: shaken cans measured on AP Oxy QC and then calculated via the head space equation.
For the ULG, we found that a combination of low pressure AND high flow was best. We have settled on ~20psi which is well below the mfr recommended set point of 50-70psi. For flow we are at 320 L/min which is higher than the mfr set point of 275 L/min. Re. flow we did find a significant negative correlation between flowrate and TPO but found it maxed out at 320 and any higher flow was deemed wasteful. We first went down this path based on various MBAA presentations we dug through - one poster (attached) actually references a Comac.
For the bubble breaker we also brought the pressure down as low as possible to break fish eye bubbles - ~4-5psi, which was also well below the set point recommended. We don't have a gas flow meter on the bubble breaker. We ultimately found there was not a linear relationship and it was more qualitative (did it break the bubbles not?), so we just make sure its breaking bubbles without wasting gas.
All the above said, we have found that good fob formation is still critical for controlling TPO. We can 'see' bad TPO based on foam formation and will adjust filler set points accordingly. Snifting and snifting stabilization are the major parameters we will adjust. Caution, as this can drive up loss. Thus far we have optimized this to keep loss at ~1-1.5% and low TPOs but know we can bring the loss % down at the expense of TPO.
It is worth noting that for the last 3 months we have been running the ULG and bubble breaker with nitrogen, as we've been under a CO2 allocation. We found no change to TPO using nitrogen.
I am interested to see what others suggestions are. We're happy with our numbers but the seamer is a major gas consumer and we'd love to bring our usage down if possible without sacrificing TPO.
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Campbell Morrissy
Head Brewer
pFriem Family Brewers
PhD Candidate
OSU - Barley Project
Original Message:
Sent: 07-05-2023 13:56
From: Aaron Crossett
Subject: Comac 14-2 Canning Line TPO issues
Hi Fancesco,
I don't have experience with that machine specifically, but I do have some experience with a comac 24-4. The DO numbers suggest that your getting a pretty good purge through the fill and I think your on the right track.
Our TPO's were stubbornly up in the 125-150 range. We ended up adjusting our bubble breaker down (physically) and significantly lowering the flowrate of CO2 to "wash over the can". It helped, but didn't get us where we wanted to be. We ended up adjusting the snift button decompression lever to get less off gassing post decompression. We got the best results with a little bit of lace as opposed to the "Black Fill" or no foam at all. Our typical DO range with this approach was 15-40ppb with TPOs in the 50-75ppb range.
If your seeing spikes on specific valves...check the snift path for flow restriction. I've cleaned hops (that somehow snuck through the centrifuge) out of those valves assemblies more times than I care to remember.
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Aaron Crossett
Director of Operations
Stone Path Malt
Wareham MA
(401) 290-7046
Original Message:
Sent: 07-04-2023 12:47
From: Francesco Mayell
Subject: Comac 14-2 Canning Line TPO issues
Hi Folks,
We have been experiencing longstanding issues with headspace O2 and TPO on our Comac 14-2 6000 CPH line and I'm wondering if anyone else with the same line has any advice. I know there are sooooo many possible avenues of investigation on this subject, and I feel like we've pretty much exhausted them, so I'm really looking for any advice that has worked specifically on this set up.
My feeling is that the underlid gassing is at the core of the issue but adjusting the flow rate on that hasn't produced any encouraging results, so I'm left wondering if there could be some design flaw in that part of the machine. We have of course tried many different settings on the filler (speed, bowl pressure, deco, purge time, fill time, etc). We have smoothed out transitions from the filler into the seamer to avoid shaking the cans. We've tried different flow rates to the bubble breaker. We have tried fabricating a custom made bubble breaker to replace the one the unit came with (to provide a more gentle, broad swath of CO2, instead of a jet). We have tried adjusting the height of the star wheel that provides the underlid gas slightly up (4mm) because it seemed like that was just purging the side of the can, not putting down a layer into the top of the can.
I know that other canning lines can fill without any foam and rely on good underlid gassing to get good results, but if we cut the foam the TPOs go through the roof. Currently the best results we obtain are with nice dense convex foam, but these results are still way too high.
Unshaken cans have DO in the 25-70ppb range
Cans shaken in a paint shaker for 5 minutes have DO averaging in the 400s ppb
Cans shaken in a paint shaker for 5 minutes have TPO averaging in the 800s ppb
We are sampling the cans with a Haffmans ISD 2.0, have tried using 3 different Haffmans o-DGMs for readings, and use the Hach calculator I found on the Master Brewer's forum to estimate the TPOs.
Thanks in advance for any advice!
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Francesco Mayell
Lead Brewer
Brixton Brewery
London
francesco.mayell@brixtonbrewery.com
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