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Thread: External wort boiler design - calandria

  1. #1
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    Sep 2011
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    External wort boiler design - calandria

    Is anyone using an external calandria on a 7-15bbl kettle? It seems that there were some threads a few years back, but I would like to hear any recent opinions on them. I am especially interested in a design for a gas-fired version, though I know they are far less common than steam.

  2. #2
    Join Date
    Oct 2003
    Location
    Madison WI
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    We use an external calandria on our 15 bbl brewhouse. 26 - 1" stainless steel tubes 5 ft long. Ours is steam heated. I haven't seen any direct fire versions. We have 2 calandria's that are identical in design. Both running from a 400K BTU boiler. They are very efficient. I don't think we could ever go back to steam jackets alone on the kettle. Many breweries have an external calandria with steam jackets on the kettle to assist in getting to a boil.

  3. #3
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    Sep 2011
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    Did you design/build the calandria yourself? Any issues with fouling of the 1" pipes? I checked your website, but couldn't find any pictures.

    Quote Originally Posted by St Rippy
    We use an external calandria on our 15 bbl brewhouse. 26 - 1" stainless steel tubes 5 ft long. Ours is steam heated. I haven't seen any direct fire versions. We have 2 calandria's that are identical in design. Both running from a 400K BTU boiler. They are very efficient. I don't think we could ever go back to steam jackets alone on the kettle. Many breweries have an external calandria with steam jackets on the kettle to assist in getting to a boil.

  4. #4
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    Oct 2003
    Location
    Madison WI
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    We didn't build or design it by ourselves. We found some existing designs and had a fabricator build it for us. Fouling of the tubes will always be an issue for internal or external calandrias. We brew 3 times/day and need to run a CIP between each batch. I have heard horror stories of others that didn't run CIP's often enough and the tubes completely plug up. Drilling them out was the only option.

  5. #5
    Join Date
    Oct 2002
    Location
    Tadcaster, Yorkshire, UK
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    You should only need to clean every couple of days. Larger scale more modern ones only need cleaning every 12 to 16 brews, I think some people have managedfar more than this, but I suspect they are not using very high hop rates, and possibly mainly extract and pellets.

    If you have to clean every brew, you are getting far too much fouling. Try increasing the circulation rate, to prevent material baking on.

    It also sounds as though your steam pressure / temperature is too high and causing fouling, suggesting you have far too little surface area. But you are where you are.

    I still suggest trialling a far bigger pump, and rinsing out with fresh water between brews so that loose fouling gets washed off instead of a full clean. You will need to generate a flow rate through each tube of not less than 1.5 metres / second, and ideally closer to 2 metres / second, to achiedve turbulent flow, for both heating and cleaning. Also consider using hydrogen peroxide addition in the caustic to remove the fouling quicker and more thoroughly. This is far kinder to stainless than hypochlorite.
    dick

  6. #6
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    Sep 2011
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    What size of internal tubing do you use? If designing one, what diameter of tubes would you suggest?

  7. #7
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    Oct 2002
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    Tadcaster, Yorkshire, UK
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    Cleaning flow rates for 26 - 1" stainless steel tubes requires 754 hl / hr (29 hl / hr per tube) to achieve 2 metres / second which is probably necessary for the degree of fouling attained by a wort heater. Even at the lowest limit of turbulent flow (normally accepted as 1.5 metres / second), the flow would need to be 563 hl / hr

    Are you really achieving this sort of flow rate ?
    dick

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