I came across some interesting sites the last few days regarding centrifugal filters. These filters spin the water in a tube which throws the solids to the outer walls at high speed and downward to lower pressure collection areas at the bottom of the device. Clean(er) water passes through a central screen filter and out the top. Some use perforated stacked discs instead of a screen. The filters are cleaned by releasing a valve at the bottom while under pressure. Some have a reverse flow mechanism to clean the screening filter more efficiently. They are similar to a vortex settlement filter but smaller and faster.
I wonder if these would be adequate for pond use or would the fast spinning merely chop up the pond waste and let it continue on to other filters? Even if it removed 50% of solids, that would improve UV sterilization performance. However, would algae merely block up the filter rendering it useless?
Generally these filters are used to separate heavy solids like sand, or are used where water is mostly pre cleaned like irrigation lines. There are some industrial uses. I could see them being used for aquariums.
My favorite of these filters (so far) is the Lakos twistIIclean filter which has a simple method for back flushing the screen filter. Price on these filters is much cheaper than large bead filters and space requirements are much smaller. Maintenance would likely require daily flushing until pond particulates are reduced. A pond system might require a couple of units in series with progressively finer mesh screens to be efficient. There is a significant price difference between the 1.5″ unit and 2″ unit (inlet/outlet size) so two 1.5 units may divide the work more evenly and work better.
I wrote to the Lakos company to learn more. I will share their response when received. Other similar items include the RUSCO filters, Thompson Filters, and swaeco centrifugal filters. These have far more active water movement than my Waterco multicyclone prefilter.
My Theoretical Application
I have a 60GPM (3600 GPH) pump and 2″ pipe leaving the pump to the multicyclone. I would likely use two 1.5 inch filters in parallel after the multicyclone. The theoretical max flow on 1.5 inch pipe is 42GPM but I am sure there must be some head loss in this filter so even if reduced down to 30GPM that is still quite fast. 2 Units would likely balance out at slightly less. My pond has a light fish load but being under a large tree I get lots of debris both large and small.
UPDATE: As suspected, the company implied that the filter would have a problem with algae build up on the screen. Since algae will grow on both sides of the screen then it will reduce the flow and require regular maintenance. Even back flush systems would not be able to clean the algae off effectively so removal would be required.
