cooling tower filter industrial water filter industrial water filtration systems COOLING TOWER FILTER Our "A" Series is used for In-line applications to ensure a continuous or intermittent flow – the flow can be maintained during backwash operation. When one vessel is in backwash mode the remaining vessels ensure the selected flow. The VORTISAND® cooling water filter is available in a variety of materials and components depending on each application requirements. Sonitec manufactures customized systems based on your specifications.