How Does Centrifugal Sand Filtration Work?
March 1, 2010
Sonitec's Vortisand, a centrifugal sand filtration system, uses a tangential inlet to introduce water with a swirling action. Centrifugal force helps to remove the suspended solids and increases the effective filter surface within the tank. This creates a concave surface on the sand media and increases the total filtration surface area.
This turbulence produces a sustained cleaning action that forces the suspended solids to accumulate on the inside walls of the tank. As a result, much finer sand can be used without any clogging problems. The water, largely free of impurities, is filtered through the media and subsequently collected.
Water passes through the sand media to the under drain at the bottom of the vessel, allowing the top-layer media to capture the contaminants. The purpose of putting the top layer of sand in motion is to use the compacted fine sand as a barrier for the ultra fine particles, so that the particles are filtered out at the surface and not deeply into the sand like conventional filters. Contaminants trapped above the sand are removed using an automatic backwash cycle, which requires much less water and a shorter operating time than traditional sand filters. This process contributes to longer cycles and much finer filtration levels.
When a preset pressure differential is reached, a backwash cycle is initiated to reverse the flow through the vessel and discharge contaminants to the waste line. The filter media is permanent and is rechargeable by a backwash at a minimum flow rate of 15 gal/min per square foot of the surface area.
For more information from Sonitec Inc., Holyoke, Mass., call (413) 532-6089 or visit www.sonitec.com.