shoreman wrote: ↑Fri Nov 08, 2019 8:38 pm
As I'm in the US I'm not able to get alot of parts and was wondering if this check valve would work on a beer engine setup: …
A long time ago "check valves" were used to stop beer flowing back to the cask from the pump. The valves in the pump should stop this but they are apt to wear out, and the beer in the pump can't be guaranteed not to be "bad" (which on returning to the cask, would turn it bad). In a home-brew situation it is less likely you would unknowingly have a leaky pump.
These days you'd have a demand valve instead of a check valve. Confusingly they are still referred to as "check valves" but operate entirely differently. They will still prevent beer returning from the pump to the cask, but also prevent beer being forced from the cask to the pump
unless a pump is trying to draw the beer. Hence "demand valve". This difference allows "bad" practices, such as attaching a pressured cask (or keg) to a hand-pump. Some so-called "craft beer" Pubs do this, so you get fizzy beer out of a hand-pump. A Pub doing this can be considered "dishonest" in that they are attempting to deceive the customers.
I of course would never recommend such deceitful practices! Err … okay, I do. If you follow my "treatise" you must have a
demand valve, not a check valve. McMullan gets away without one because, as he has said earlier in this thread, he follows the "intermediary" route (container fitted to hand-pump is unpressured). The other option I present is to use Corny kegs connected to the handpump and to CO2 via a variable "LPG" regulator. Even then, if the cask is six foot lower than the pump you can dispense with the demand valve and static pressure (six foot of water applies just over 2psi) will keep the beer in the cask. But I can't recommend this. Currently one of my hand-pumped beers has undergone a little "secondary" fermentation and is at 4-5psi. My gas lines have venting apparatus built-in so I can vent the cask back down again, but 4-5psi without a demand valve would have pushed beer through the pump to create a puddle on the floor!
(Side note: A check valve will hold back some pressure due to it having a "cracking pressure". But manufacturers try to keep "cracking pressures" as small as possible, so you can't rely on it).