Water-mixing device, sand trap and method of using same

A static mixer device, comprising:

• a conduit comprising an upper mixing chamber, a swirl chamber, a lower mixing chamber and a diverter chamber;
• a cap;
• and
• a diffuser plate;
• the upper mixing chamber having a first inlet and a first outlet and an axial centerline in a longitudinal direction of main stream flow;
• the swirl chamber having a second inlet and a second outlet, the second inlet being in fluid communication with the first outlet of the upper mixing chamber;
• the lower mixing chamber having a third inlet and a downwardly directed third outlet and an axial centerline in the longitudinal direction of main stream flow, the third inlet of the lower mixing chamber being in fluid communication with the second outlet of the swirl chamber;
• a plurality of baffles arranged within the upper mixing chamber and the lower mixing chamber, wherein the plurality of baffles are shaped and arranged for subdividing a flow of an additive material against a plurality of portions of an internal perimeter of the upper mixing chamber and the lower mixing chamber, and for redirecting the subdivided flow of the additive material to the axial centerline of the upper and lower mixing chambers to form a single direction mixing vortex axial to the centerline of the upper mixing chamber and the lower mixing chamber;
• the diverter chamber having sidewalls provided at a lower end of the conduit below the lower mixing chamber, the diverter chamber having a fourth inlet and a fourth outlet, the fourth inlet being in fluid communication with the third outlet of the lower mixing chamber and arranged in the longitudinal direction of the main stream flow of the lower mixing chamber, and the fourth outlet comprising a plurality of slits in the diverter chamber sidewalls, the slits being radially arranged relative to the axial direction of the lower mixing chamber;
• the cap having a bottom wall and one or more cap sidewalls, the cap being connected to a lower portion of the diverter chamber, and the cap sidewalls spaced from the diverter chamber and having a height that extends upwardly at least approximately to a height of the plurality of slits to overlap the slits and define an annular region between inner surfaces of the cap sidewalls of the cap and outer walls of the diverter chamber;
• the diffuser plate being spaced from an upper edge of the cap to define a discharge area, the diffuser plate extending radially from the conduit to define a surface which overlaps the entire annular opening defined by an upper edge of the cap and the conduit, the diffuser plate being generally parallel to the upper edge of the cap.