Wort and Beer Pumping Velocities
Does anyone know the recommended wort and beer maximum pumping velocities to minimise shearing/product damage. I am frustrated because I did some reading a few weeks ago and can't remember where I read it.
just in case anyone is interested, i found the answer i was looking for. according to Kunze the recommended flow velocity for beer and wort is < 3.0m/s, with velocities excess of this OK for short distances.
I am surprised he gives flow rates that high. Effective turbulent flow for cleaning starts at about 1.8 meters/sec, though some people reckon 1.5 is sufficient. Anything above 2.2 will be wasting energy for no real benefit, but with a large increase in back pressure over longer runs. You need sufficient flow for clean beer / water interfaces, which means turbulent flow - but not much above - i.e. somewhere between 1.5 and 1.8 m/s should do it. This fits in with my memory when I started out andd we were still using imperial measurement of speeds being quoted as 5 ft / sec for beer flow, 7 ft / sec for cleaning.
I guess if you take the question / answer as what point does damage occur, then his answer is undoubtedly correct, but......
Here are some miscellaneous max. velocity numbers as recommended by Siebel:
1.5m/s for CO2-contaning fluid (to avoid shear)
3m/s for water
20m/s for CO2 gas
20m/s for compressed air
25m/s for steam
1.5m/s for glycol cooling medium
1.5m/s for milk
2m/s for non-sparkling beverages
There are a couple of extras in here for interest, but the recommendation for milk is interesting and is consistent with my previous experience...