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    Planctonite’s Skimmer Fan & Tetra’s Patent

    Planctonite’s new BOT skimmer is pretty interesting. Think Berlin Triple Pass meets Seaclone, but a hell of a lot better. The skimmer uses a fan blade, dubbed the Dynamo, that is powered by the output of your normal Pinwheel fitted skimmer pump. This creates a cyclone effect within the reaction chamber. It’s a novel idea. […]

    protein skimmer fan

    Planctonite’s new BOT skimmer is pretty interesting. Think Berlin Triple Pass meets Seaclone, but a hell of a lot better. The skimmer uses a fan blade, dubbed the Dynamo, that is powered by the output of your normal Pinwheel fitted skimmer pump. This creates a cyclone effect within the reaction chamber.

    It’s a novel idea. But where have I seen this before? I did some searching around and then it hit me. Tetra has a patent on a “Protein Skimmer with Stationary Fan”. The patent was filed back in February 2009, and granted in August 2010.

    protein skimmer fan

    From the patent:

    “The deflector causes the aerated water to swirl as it moves up through the reaction chamber by imparting a sideward or substantially horizontal water flow. The sideward, horizontal flow in combination with a natural vertical rise causes a rotational or swirling flow within the reaction chamber…the swirling action lengthens the flow pathway and increases the distance that the bubbles travel within the reaction chamber. The extend (sic) travel distance accordingly decreases the vertical speed at which the bubbles rise within the reaction chamber and increases the dwell time of the bubbles within the reaction chamber. This swirling action thereby desirably increases the reaction time between the bubbles and the protein in the water of the reaction chamber to improve the efficiency of protein removal.” [List of claims can be found here]

    All that swirling talk brings back memories of the inefficient skimmers of the 90s! What is interesting in this design is that by forcing the deflector, or stationary fan, to move via the pumps output, the velocity of the air water mixture is drastically reduced–similar to the much employed bubble plate.

    While we think Planctonite is closer to the mark with their design, Tetra’s patent may hinder the use of this stationary fan concept going forward. …And maybe, just maybe, we’re all trying too hard in the name of foam fractionation.

    2 Comments

    1. December 1, 2010 at 8:29 PM | Permalink

      Tetras patent is on a stationary fan, and the one used by Planctonite is rotating in a passive manner… two different things. Using a ‘passive centrifugal turbine’ INSIDE a bubble plate is a good idea that I have tried, to spread out the water pressure under the plate, but I dont see it as so great by itself. The Planctonite ‘turbine’ also has a secondary function of acting sort of like a turbo to create a downdraft in the center from the turbine itself and the natural effects of a vortex. This is adding turbulence if anything… now you have water trying to rise AND then recirculate inside the same skimmer diameter. I dont know about that…

      I suppose if you subscribe to the ‘classic ideas’ about skimming where contact/dwell time as the bubble rises within the main reaction area is of highest interest (Escobal), this method would make sense. If it wasnt for the extra turbulence in this case, I would say this makes sense for trying to get out some organics that a skimmer with less contact time would use. Freshwater skimmers are a good example where this comes into play… very tall but also low turbulence (as low as you can expect considering the bubbles are allowed to rise longer and combine resulting in more turbulence as they crash into the bottom of the ‘head’ collecting in the neck).

      If you subscribe to some of the more recent ideas such as those used by the ‘high efficiency’ skimmers that use bubble plates and high air/water ratio pumps to generate a huge foamy head that concentrates on reaction/dwell times in the neck/head rather than in the main reaction chamber; this method seems like a step backwards.

    2. Ziyaadoo
      December 3, 2010 at 5:53 AM | Permalink

      “And maybe, just maybe, we’re all trying too hard in the name of foam fractionation.” I agree

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