Apparatus for fluid treatment

Abstract

Abstract Apparatus for treating fluid in which the fluid is passed through a bed of solid particles, such as filter media or ion exchange resins, is provided with improved means for supporting the bed and improved means for backwashing the bed. The apparatus includes an outer vessel having a closed bottom and an inner vessel having an open bottom. The inner vessel is positioned above the bottom of the outer vessel. Thus, there is an opening between the inner vessel and the bottom of the outer vessel. The bed of solid particles is supported by the bottom of the outer vessel and extends up into at least one of the vessels. The bed covers the opening between the inner vessel and the bottom of the outer vessel. An inlet conduit admits fluid to one of the vessels and the fluid passes down through the bed and through the opening into the other vessel. Since the bed is supported by the outer vessel, expensive support paraphernalia such as underdrains and strainers are not required. Preferably, at least one of the vessels has a closed top, and an outlet conduit communicates with this vessel at an intermediate level. Thus, fluid accumulates in the vessel with the closed top and a pocket of air is trapped above the accumulated fluid. The outlet conduit includes means for restricting the flow of fluid from the vessel so that the trapped air is compressed. The bed is backwashed by reducing pressure on the inlet side of the bed, whereby the compressed air forces the accumulated fluid back through the bed and through a backwash outlet conduit communicating with the other vessel above the bed. During the backwash cycle, air may be withdrawn from the pocket of compressed air and injected into the bed, so that a mixture of air and fluid will pass through the bed and scour the particles.

Inventors

• 👤 W Maroney

Bibliographic Details