Results 1 to 6 of 6

Thread: Using CO2 for Pneumatic Valves

  1. #1
    Join Date
    Jun 2012
    Posts
    215

    Using CO2 for Pneumatic Valves

    We just got a 2 head semi auto keg washer. This particular keg washer has an inlet for compressed air which it uses to run the air valves, initial keg purge, initial post rinse water purge, caustic recovery, and post caustic rinse water purge.

    We prefer to use acid rather than caustic in our keg washing process, and I don't like the idea of pumping compressed air into our kegs. Especially since I would have to purchase a larger compressor with enough capacity in addition to filters.

    I've been using a nitrogen cylinder for the first few trial runs rather than compressed air and it's working pretty good, however, nitrogen is much more expensive than our bulk CO2 and this thing uses quite a bit of gas.

    Is there any risk to using CO2 to run the air valves? I asked the "manufacturer" and their reply was that they have not tested it so they couldn't comment either way. I say "manufacturer" because I assume it was made in China as the manual lists all pressure specs in MPa and bar rather than psi and it's written in poorly translated Engrish.

    Inlet pressure to air valves is 70psi.
    Last edited by d_striker; 02-13-2018 at 04:51 PM.

  2. #2
    Join Date
    Oct 2013
    Location
    Dallas, Bangalore and soon Goa
    Posts
    299
    You should be able to run pneumatics fine with co2. If you are using the acid instead of caustic, you won't have issues with it process wise. You are still going to be introducing oxygen in your kegs via the water rinse (unless you use de-aerated water) if that is your main concern, however it will be less overall oxygen exposure. The difference will be in cost. You will be using a lot of co2 to clean kegs and the costs will eventually stack against you. A compressor and drier are more economical in the long run. The other disadvantage is in the rate of supply. Depending on how often and how many kegs you will be running, you will draw fast enough to freeze your co2 supply. This can happen easily even without using co2 on pneumatics and drain purges. It is amplified if using co2 to carbonate beer at the same time. A high flow regulator is a big help, and evaporator towers help a lot to. You can also go low tech and use a "pig" or buffer tank to help ease the draw.

  3. #3
    Join Date
    Aug 2010
    Location
    Enterprise, Oregon
    Posts
    1,664
    CO2 is reactive and will break down seals and regulator diaphragms not spec'ed for it. CO2 also present hazards of suffocation and poisoning if the room is not adequately ventilated. And it's expensive compared to compressed air. Get a compressor and air dryer.
    Timm Turrentine

    Brewerywright,
    Terminal Gravity Brewing,
    Enterprise. Oregon.

  4. #4
    Join Date
    Jun 2012
    Posts
    215
    Quote Originally Posted by TGTimm View Post
    CO2 is reactive and will break down seals and regulator diaphragms not spec'ed for it. CO2 also present hazards of suffocation and poisoning if the room is not adequately ventilated. And it's expensive compared to compressed air. Get a compressor and air dryer.
    What capacity tank should I be looking at for a two head semi auto? Can you recommend a particular compressor and drier? In addition to a drier, do I need to be looking at oil filters and/or sterile air filters?

    We're only a small brewpub and clean a max of 15-20 kegs per session, two times per week.
    Last edited by d_striker; 02-14-2018 at 11:49 AM.

  5. #5
    Join Date
    Aug 2010
    Location
    Enterprise, Oregon
    Posts
    1,664
    You need to consult your manual for air consumption. Usually, the amount of air delivered over a short period of time determines how long it takes to wash a keg, esp. during the flush. Because these demands are periodic, with time between cycles, a very high-output compressor isn't as important as storage. I buy used tanks from our compressor supplier for this purpose.

    Yes, you'll need a filter/separator before the air dryer, and I highly recommend a micro-filter after.
    Timm Turrentine

    Brewerywright,
    Terminal Gravity Brewing,
    Enterprise. Oregon.

  6. #6
    Join Date
    Oct 2013
    Location
    Dallas, Bangalore and soon Goa
    Posts
    299
    Quote Originally Posted by TGTimm View Post
    CO2 is reactive and will break down seals and regulator diaphragms not spec'ed for it. CO2 also present hazards of suffocation and poisoning if the room is not adequately ventilated. And it's expensive compared to compressed air. Get a compressor and air dryer.
    The co2 is reactive, but so are most all compounds including regular breathing air. Any seal material you find in a solenoid will likely have a "B" (slightly corrosive) or better rating for chemical compatibility for co2. Same holds true for most regulator diaphragms. Common seal materials might include EPDM, Viton, Silicone, PTFE, Buna, Natural Rubber, Neoprene, Fluorocarbon, and possibly others in special applications. It is much more likely the Chinese solenoid will have the coil fail before the seal due to corrosion.

    The suffocation hazard is a very valid point, especially if working in closed in areas. In a large warehouse, not nearly as concerning as it will drop to the floor. But of course you would be washing a lot more kegs then. It is a very real risk.

    Ingersoll Rand makes some very nice (but expensive) compressor and drier set ups. You can usually piece something a bit cheaper from your local stores. Some will hate on the oil-less compressors out there but there is a lot more to it than that. Buy a quality unit and not the cheapest thing you can get away with, you will thank yourself later. www.CAGI.org has a huge amount of information about compressors if you care to become an expert.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •