An underdrain assembly for filtering particulates from a fluid having an upper structure connected to a bottom plate. At least one flow control vane is positioned between the upper structure and the bottom plate for directing and managing fluid flow through the assembly. The upper structure can have first and second filtration members, the second filtration member positioned between the first filtration member and the bottom plate. The second filtration member can have a shape that restricts fluid flow within the underdrain. The underdrain can have air and water inlets. The water inlet can have an end with a plate covering an upper portion thereof. The end can also include an opening having an angular cut forming an angle with respect to a longitudinal axis of the water inlet. Thus arranged, air is prevented from migrating out the water line. A resilient mounting arrangement for the underdrain is also disclosed.

A modular underdrain system is disclosed. The modular underdrain system may comprise an intermediate modular component having a first peripheral side including a first mating portion and a second peripheral side including a second mating portion. The first peripheral side may comprise at least one transfer orifice. An intermediate plate member is disposed intermediate the first peripheral side and the second peripheral side along a width dimension. The intermediate plate member may comprise a metering pipe opening. A metering pipe may be sized to be positioned within the metering pipe opening.

A modular underdrain system is disclosed. The modular underdrain system may comprise an intermediate modular component having a first peripheral side including a first mating portion and a second peripheral side including a second mating portion. The first peripheral side may comprise at least one transfer orifice. An intermediate plate member is disposed intermediate the first peripheral side and the second peripheral side along a width dimension. The intermediate plate member may comprise a metering pipe opening. A metering pipe may be sized to be positioned within the metering pipe opening.

An underdrain apparatus and a method for manufacturing such apparatus are provided. The underdrain apparatus can be extruded in long sections as a unitary part. The underdrain apparatus may be extruded in various sizes, shapes, and materials. Further, the underdrain apparatus may include a passageway for transporting water to and from the filter media and/or air to the filter media. In some embodiments, apertures are formed in the underdrain apparatus during an extrusion process to provide a path between the passageway and the filter media.

An underdrain apparatus and a method for manufacturing such apparatus are provided. The underdrain apparatus can be extruded in long sections as a unitary part. The underdrain apparatus may be extruded in various sizes, shapes, and materials. Further, the underdrain apparatus may include a passageway for transporting water to and from the filter media and/or air to the filter media. In some embodiments, apertures are formed in the underdrain apparatus during an extrusion process to provide a path between the passageway and the filter media.

A support grid assembly for use in a vessel. The support grid assembly includes panels each including a first wall including a media-supporting screen and a second wall to be supported by the vessel wall inner surface. A manifold is coupled to the panels and is in hydraulic communication with vessel outlet. The manifold and the panels permit fluid to flow through the screen in each panel, through the panels, into the manifold, and through the manifold to the outlet of the vessel, as well as in the reverse direction. At least a portion of the first wall may slope downward toward the manifold, and at least a portion of the second wall may form a bottom surface that is curved to substantially conform to a curvature of the vessel wall inner surface. The panels may be arranged in a circular configuration extending radially from the manifold.

A support grid assembly for use in a vessel. The support grid assembly includes panels each including a first wall including a media-supporting screen and a second wall to be supported by the vessel wall inner surface. A manifold is coupled to the panels and is in hydraulic communication with vessel outlet. The manifold and the panels permit fluid to flow through the screen in each panel, through the panels, into the manifold, and through the manifold to the outlet of the vessel, as well as in the reverse direction. At least a portion of the first wall may slope downward toward the manifold, and at least a portion of the second wall may form a bottom surface that is curved to substantially conform to a curvature of the vessel wall inner surface. The panels may be arranged in a circular configuration extending radially from the manifold.

An underdrain assembly for filtering particulates from a fluid having an upper structure connected to a bottom plate. At least one flow control vane is positioned between the upper structure and the bottom plate for directing and managing fluid flow through the assembly. The upper structure can have first and second filtration members, the second filtration member positioned between the first filtration member and the bottom plate. The second filtration member can have a shape that restricts fluid flow within the underdrain. The underdrain can have air and water inlets. The water inlet can have an end with a plate covering an upper portion thereof. The end can also include an opening having an angular cut forming an angle with respect to a longitudinal axis of the water inlet. Thus arranged, air is prevented from migrating out the water line. A resilient mounting arrangement for the underdrain is also disclosed.

An underdrain assembly for filtering particulates from a fluid having an upper structure connected to a bottom plate. At least one flow control vane is positioned between the upper structure and the bottom plate for directing and managing fluid flow through the assembly. The upper structure can have first and second filtration members, the second filtration member positioned between the first filtration member and the bottom plate. The second filtration member can have a shape that restricts fluid flow within the underdrain. The underdrain can have air and water inlets. The water inlet can have an end with a plate covering an upper portion thereof. The end can also include an opening having an angular cut forming an angle with respect to a longitudinal axis of the water inlet. Thus arranged, air is prevented from migrating out the water line. A resilient mounting arrangement for the underdrain is also disclosed.

A filtration system has at least one underdrain lateral, a flume, and at least one metering plate. The metering plate includes a plate member with at least one opening configured to receive liquid or gas therethrough at a first flow rate during a backwash function and is configured to receive liquid or gas therethrough at a second, lower flow rate during filtration. A method of metering gas into a filtration system with a metering plate is also disclosed. The metering plate allows gas to flow into each underdrain lateral at two very different flow rates.