Having invented the expeller used in hydrodynamic sealing technology for more than 85 years, A.R. Wilfley & Sons is a manufacturer of centrifugal pumps with advanced seal technology for abrasive and corrosive applications. Products include chemical pumps, chemical slurry pumps and slurry pumps that meet ASME specifications. These are available in a variety of materials and configurations, including dynamic seal and a selection of single- and double-mechanical seals. The company also offers axial-flow, vertical-cantilever and vertical-sulfuric acid pumps through a partnership with Ensival-Moret. Other products include dynamic sealing or hydrodynamic sealing, which is accomplished by a combination of pumping vanes on the rear shroud of the impeller and a secondary expeller located behind the impeller. A.R. Wilfley & Sons maintains operations in Greenwood Village, Colo.