Patent Application
20120067968
This disclosure relates to water treatment, and more particularly to apparatus for introducing solutions of dry chemicals into a water stream.
Water treatment is needed in a variety of applications. Untreated water provides a hospitable environment for the growth of bacteria, algae, and other undesirable and potentially unhealthful organisms. It has become common practice to treat water on a periodic or continuous basis by introducing treatment chemicals to control such organisms.
Chemical feeders have been developed for bringing water into contact with solid, dry treatment chemicals so that the chemical material is dissolved in the water in a controlled manner. In a typical application of a chemical feeder, the feeder dissolves solid pellets of calcium hypochlorite (cal hypo) to introduce chlorine into the water stream; the quantity of chlorine in the water is generally expressed as a concentration of free available chlorine (FAC). An effective feeder design must provide dissolution at a desired rate, so as to maintain the desired FAC concentration, while avoiding undesirable deposits or residues; this is especially important in the case of cal hypo which produces calcium carbonate deposits. In particular, it is desirable to implement a chemical feeder that can continuously deliver a high concentration of FAC for an extended period of unattended operation.
In accordance with the disclosure, an apparatus and method are provided for preparation of a chemical solution.
According to one aspect of the disclosure, ah apparatus includes a lower housing and an upper housing. The lower housing has a base, an upper plate, and a side wall; the upper plate has a central opening therein. The upper housing has a side wall, a lower extremity of which is connected to the upper plate. A grid is mounted on the upper plate and covers the central opening; the grid forms at least a portion of a lower boundary of an upper chamber within the upper housing. A wall within the lower housing divides the interior of the lower housing into a central inner chamber and an annular outer chamber; this wall has a height substantially equal to an interior height of the side wall of the lower housing. One portion of the wall has a reduced height to permit fluid flow from the inner chamber to the outer chamber. A nozzle is disposed in the inner chamber for discharging fluid into the inner chamber toward the grid, so as to cause a fluid surface in the inner chamber to be locally elevated in a portion of said surface. In an embodiment, the nozzle is an eductor having fluid intake ports to create a venturi effect and thereby draw fluid in the inner chamber into the eductor.
In operation, the eductor causes the fluid surface in the inner chamber to be locally elevated in an area above the nozzle, so that the surface in that area rises above the grid; the fluid rising above the grid dissolves chemical material located in the upper chamber and disposed on the grid. The chemical material may be in the form of tablets, briquettes, chips, pellets, granules, etc. Dissolved material then drops down through the grid into the inner chamber and mixes with fluid in the inner chamber. The chemical solution then flows from the inner chamber to the outer chamber and out through an outlet port.
According to another aspect of the disclosure, a method for preparing a chemical solution includes the steps of providing a chemical feeder with an upper housing having a grid at the bottom thereof and lower housing having a nozzle oriented so as to discharge water vertically upward toward the grid; discharging fluid from the nozzle to cause a fluid surface in the chemical feeder to be locally elevated in an area above the nozzle, so that the surface in that area rises above the grid; dissolving chemical material disposed on top of the grid, in accordance with the fluid rising above the grid; and conducting a mixture of water and the dissolved material out of the lower housing.
The foregoing has outlined, rather broadly, the preferred features of the present disclosure so that those skilled in the art may better understand the detailed description of the disclosure that follows. Additional features of the disclosure will be described hereinafter that form the subject of the claims of the disclosure. Those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiment as a basis for designing or modifying other structures for carrying out the same purposes of the present disclosure and that such other structures do not depart from the spirit and scope of the disclosure in its broadest form.
The upper plate 12 has a central opening which is covered by a grid 10. Upper housing 3 has a side wall 13, the bottom extremity of which connects to upper plate 12 while surrounding grid 10. The inner surface 23 of side wall 13, at the bottom extremity of side wall 13, is proximate to or adjacent to the outer edge 9 of grid 10. Upper housing 3 has a removable lid 14; in this embodiment, lid 14 is secured to the top edge of side wall 13 by an O-ring seal. As shown in
A wall 4 within lower housing 2 surrounds the central portion of the interior of lower housing 2, and accordingly divides the interior of lower housing 2 into an inner chamber 6 and an annular outer chamber 7. (Inner chamber 6 is thus located within the cavity defined by base 17 and side wall 11.) The bottom of wall 4 is connected to base 17. Wall 4 has a height substantially equal to the interior height of outer side wall 11, except for a portion in which the top of the wall has a cutout 5.
A nozzle is mounted in the inner chamber for discharging fluid toward the grid. In this embodiment, the nozzle comprises an eductor 15, mounted vertically so that an outlet port thereof is directed upward toward the grid. Eductor 15 has an inlet port connecting to a water feed line (not shown) through a coupler 16. In this embodiment, coupler 16 is disposed in an opening in base 17, connecting to the feed line underneath the base. Eductor 15 is configured to mix water from the feed line with chemical solution already formed in the feeder, drawing the solution through ports that create a venturi effect. The chemical solution is conducted out of the outer chamber of the feeder through an outlet port 18 located in the outer side wall 11.
Interior wall 4 is shown in isolation in
During operation of the feeder (see
The surface of the fluid in this area 62 rises above the grid, so as to contact pieces 81 of the dry chemical resting on the central portion of the grid. The dry chemical pieces 81 thus dissolve, the dissolved chemical dropping down through the grid into the inner chamber 6 and resulting in formation of a chemical solution in inner chamber 6. As noted above, the chemical solution is drawn back into the eductor (arrows 43) through the eductor intake ports 42, and is again discharged through outlet port 41. The chemical solution overflows into outer chamber 7, spilling over wall 4 in the area of cutout 5; the solution then exits the feeder through outlet port 18.
Cone 52 is shown in isolation in
In another embodiment, illustrated in
While the disclosure has been described in terms of specific embodiments, it is evident in view of the foregoing description that numerous alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the disclosure is intended to encompass all such alternatives, modifications and variations which fall within the scope and spirit of the disclosure and the following claims.
