Fog Nozzle SkimmerThe most popular aquarium protein skimmers are of the venturi, downdraft, or HSA-type. They operate by pushing a jet of water through a nozzle of some sort. The nozzle has a low pressure zone, which is connected to the open air, and air bubbles are entrained into the water stream at this point. The effect is essentially to create a spray of air within a moving water stream. The amount of surface area where water meets air has a lot to do with the effectiveness of the skimmer. Although we may be impressed by the amount of air drawn in by new skimmers such as the HSA, and other skimmers based on the Beckett foam head, I think we can do even better.
In my latest skimmer design, I have tried to reverse the ratio of air and water. Instead of injecting a moderate amount of air into a water stream, I inject a moderate amount of atomized water into a free air stream. I do this with an atomizing spray nozzle.
The spray nozzle creates a fine fog of water, as shown to the left. The nozzle itself appears at right. It operates by injecting a fine stream of high velocity water against a straight pin of the same diameter. The result is a fine atomization of the water.
The water fog is injected into a traditional separator, like the box part of a downdraft skimmer.
The skimmer itself is still undergoing my extensive and rigorous testing procedure. I will have pictures of the final product in the near future.
Below, you can see me removing an earlier version of the nozzle design from the annealing oven, which I built from firebrick and baling wire. The design below proved to create a somewhat coarser spray than the nozzle shown above. The nozzle above is made by a process similar to that of the one below. Both nozzles are made from 316 stainless steel, which is corrosion resistant enough for use in seawater, and a lot stronger than plastics.