Patent Description:
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. <CIT> relates to feeders for introducing treatment chemicals into a recirculating water stream from a swimming pool or the like.

<CIT> discloses in particular an apparatus for dissolving and delivering a solution of a solid chemical material including a housing having a base member and upwardly extending side walls, said base member and side walls defining a cavity, and a chamber having side walls within said cavity, the bottom of the side walls of said chamber being adjacent to said base member and the side walls of said chamber being spaced from the side walls of the housing, an improvement comprising: a nozzle disposed in said chamber for discharging fluid in which said solid chemical material is soluble upwardly into an inner chamber, so as to cause a fluid surface in the inner chamber to be locally elevated in a portion of said surface and a method for preparing a chemical solution, comprising: providing a chemical feeder including an upper housing having a grid at the bottom thereof, and a lower housing having a nozzle installed therein, the nozzle oriented so as to discharge fluid 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 of said surface above the nozzle, so that the surface in said area rises above the grid; dissolving chemical material disposed on top of the grid, in accordance with the fluid rising above the grid and thereby contacting the chemical material; and conducting a fluid mixture including the dissolved material out of the lower housing.

In accordance with the disclosure, an apparatus according to claim <NUM> and method according to claim <NUM> are provided for preparation of a chemical solution.

According to one aspect of the disclosure, an 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. The nozzle comprises 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.

<FIG> illustrates an apparatus for dissolving dry chemicals (a chemical feeder <NUM>) according to an embodiment of the disclosure. Feeder <NUM> has a lower housing <NUM> and an upper housing <NUM>. (Components of feeder <NUM>, including housings <NUM>, <NUM>, are shown as circular cylinders; it will be appreciated that alternate embodiments of the disclosure may have shapes other than circular cylinders. ) Lower housing <NUM> has an outer side wall <NUM>, an upper plate <NUM> and a base <NUM>; the outer side wall extends upward from the base to the upper plate. In an embodiment, base <NUM> and side wall <NUM> define a cavity.

The upper plate <NUM> has a central opening which is covered by a grid <NUM>. Upper housing <NUM> has a side wall <NUM>, the bottom extremity of which connects to upper plate <NUM> while surrounding grid <NUM>. The inner surface <NUM> of side wall <NUM>, at the bottom extremity of side wall <NUM>, is proximate to or adjacent to the outer edge <NUM> of grid <NUM>. Upper housing <NUM> has a removable lid <NUM>; in this embodiment, lid <NUM> is secured to the top edge of side wall <NUM> by an O-ring seal. As shown in <FIG>, the interior space bounded by side wall <NUM> forms an upper chamber <NUM> with grid <NUM> at the bottom thereof.

A wall <NUM> within lower housing <NUM> surrounds the central portion of the interior of lower housing <NUM>, and accordingly divides the interior of lower housing <NUM> into an inner chamber <NUM> and an annular outer chamber <NUM>. (Inner chamber <NUM> is thus located within the cavity defined by base <NUM> and side wall <NUM>. ) The bottom of wall <NUM> is connected to base <NUM>. Wall <NUM> has a height substantially equal to the interior height of outer side wall <NUM>, except for a portion in which the top of the wall has a cutout <NUM>.

A nozzle is mounted in the inner chamber for discharging fluid toward the grid. The nozzle comprises an eductor <NUM>, mounted vertically so that an outlet port thereof is directed upward toward the grid. Eductor <NUM> has an inlet port connecting to a water feed line (not shown) through a coupler <NUM>. In this embodiment, coupler <NUM> is disposed in an opening in base <NUM>, connecting to the feed line underneath the base. Eductor <NUM> 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 <NUM> located in the outer side wall <NUM>.

Interior wall <NUM> is shown in isolation in <FIG>. In this embodiment, a portion of the wall (typically about <NUM>° of arc), has its height reduced by cutout <NUM>, permitting fluid flow from the inner chamber to the outer chamber over the wall at the cutout portion. The arc of cutout <NUM> may vary from <NUM> ° of arc to <NUM>° of arc, in which case the entire wall has its height reduced to permit fluid flow over the wall in any direction. As shown in <FIG>, the reduction in height is typically a small fraction of the height of the wall; when the wall is installed inside housing <NUM>, the top edges <NUM>, <NUM> of both the cutout portion and the remainder of the wall are in the upper part of the interior of housing <NUM>. During operation of the feeder, chemical solution in the inner chamber <NUM> overflows into the outer chamber <NUM> over the reduced-height portion of the wall, and then exits the outer chamber through outlet port <NUM>. Cutout <NUM> is oriented to be <NUM>° opposite port <NUM> (see <FIG> and <FIG>), so that flow from the inner chamber into the outer chamber is in the direction opposite to flow out of the feeder through outlet port <NUM>.

<FIG> is a detail view of the outer edge portion of grid <NUM>; grid <NUM> covers the opening in upper plate <NUM> and is surrounded by wall <NUM>. In this embodiment, upper plate <NUM> has a notch <NUM> formed therein, so that the thickness of upper plate <NUM> is reduced in an inner edge portion <NUM>. Grid <NUM> is mounted on top of and supported by edge portion <NUM>. The depth of notch <NUM> may be chosen so that the top surface <NUM> of upper plate <NUM> and the top surface <NUM> of grid <NUM> are coplanar. In addition, as shown in <FIG>, the inner diameter of wall <NUM> may be matched to the diameter of grid <NUM> so that inner surface <NUM> of wall <NUM> is adjacent to the outer edge of the grid. As shown in <FIG>, grid <NUM> generally has a uniform thickness less than that of upper plate <NUM>; grid <NUM> does not extend below the plane of the underside <NUM> of upper plate <NUM>.

<FIG> illustrates details of eductor <NUM>; eductor <NUM> is for example a "Tank Mixing Eductor" from Spraying Systems Co. , Wheaton, Illinois. The eductor has an inlet port <NUM> that connects to water feed line <NUM>, and a discharge port <NUM>. (Coupler <NUM> is omitted from <FIG> to more clearly show the eductor inlet. ) The eductor also has fluid intake ports <NUM> that create a venturi effect and thereby draw chemical solution back into the eductor, as shown schematically by arrows <NUM>.

During operation of the feeder (see <FIG>), pieces of dry chemical material <NUM> (in the form of tablets, briquettes, chips, pellets, granules, or the like) in upper chamber <NUM> rest on top of grid <NUM>. Water enters the feeder through eductor <NUM>. Discharge <NUM> from the eductor causes the fluid surface <NUM> in the inner chamber <NUM> to be locally elevated in an area <NUM> of the surface above the eductor. In this embodiment, the inner chamber is a circular cylinder with eductor <NUM> mounted in a radially central portion thereof; accordingly, the locally elevated portion <NUM> of the fluid surface will be at a central circular portion of the grid.

The surface of the fluid in this area <NUM> rises above the grid, so as to contact pieces <NUM> of the dry chemical resting on the central portion of the grid. The dry chemical pieces <NUM> thus dissolve, the dissolved chemical dropping down through the grid into the inner chamber <NUM> and resulting in formation of a chemical solution in inner chamber <NUM>. As noted above, the chemical solution is drawn back into the eductor (arrows <NUM>) through the eductor intake ports <NUM>, and is again discharged through outlet port <NUM>. The chemical solution overflows into outer chamber <NUM>, spilling over wall <NUM> in the area of cutout <NUM>; the solution then exits the feeder through outlet port <NUM>.

<FIG> illustrates another embodiment of the disclosure, in which feeder <NUM> has an upper chamber <NUM> with a diameter larger than that of upper chamber <NUM> in feeder <NUM>. Feeder <NUM> therefore can hold a larger quantity of dry chemicals; this is an advantage in applications where the feeder is to operate unattended for extended periods. The lower extremity of side wall <NUM> is spaced apart from the outer edge of grid <NUM>. To direct pieces of dry chemical inward toward grid <NUM> and prevent pieces of dry chemical from landing on plate <NUM> instead of grid <NUM>, chamber <NUM> has a cone-shaped insert <NUM> mounted therein.

Cone <NUM> is shown in isolation in <FIG>. As shown in <FIG>, cone <NUM> has a small lower open end and a large open upper end. The outer edge <NUM> of the upper end contacts the interior surface of the side wall of the upper housing, and the lower end has an inner edge <NUM> with a circumference approximately matching that of the grid, so that inner edge <NUM> is proximate to the outer edge of the grid.

In another embodiment, illustrated in <FIG>, the water feed line connection is through the side wall <NUM> rather than through the base <NUM>. Eductor <NUM> is connected through coupler <NUM> and a <NUM>° elbow <NUM> to a substantially horizontal water feed line <NUM>. Water feed line <NUM> extends through an opening in wall <NUM> and connects to inlet port <NUM>.

<FIG> shows concentrations of FAC in solution produced by a feeder embodying the disclosure at various flow rates. Flow rates were in the range <NUM>-<NUM> gallons per minute (GPM), corresponding to water pressure in the range <NUM>-<NUM> psi. The eductor inlet port had a diameter of approximately <NUM>/<NUM> inch, and the eductor outlet was located <NUM>-<NUM>/<NUM> inch below the grid. FAC concentrations were obtained in the range <NUM>-<NUM> ppm, varying nearly linearly with the flow rate. It will be appreciated that these FAC concentrations are substantially higher than obtained from typical chemical feeders.

Claim 1:
An apparatus (<NUM>) for dissolving and delivering a solution of a solid chemical material (<NUM>) including
an upper housing (<NUM>) having a grid (<NUM>) at the bottom thereof and configured such that during operation of the apparatus (<NUM>) the solid chemical material (<NUM>) is located in the upper housing (<NUM>) and disposed on top of the grid (<NUM>),
a lower housing (<NUM>) having a base member (<NUM>) and upwardly extending side walls (<NUM>), said base member (<NUM>) and side walls (<NUM>) defining a cavity,
an inner chamber (<NUM>) within the lower housing (<NUM>) and having side walls (<NUM>) within said cavity, the bottom of the side walls (<NUM>) of said chamber being adjacent to said base member (<NUM>) and the side walls (<NUM>) of said inner chamber (<NUM>) being spaced from the side walls (<NUM>) of the lower housing (<NUM>), and
an outlet port (<NUM>) for conducting the chemical solution out of the lower housing (<NUM>),
characterized by:
a nozzle comprising an eductor (<NUM>) disposed in said inner chamber (<NUM>) for discharging fluid (<NUM>) in which said solid chemical material (<NUM>) is soluble upwardly into the inner chamber (<NUM>), so as to cause a fluid surface (<NUM>) in the inner chamber (<NUM>) to be locally elevated (<NUM>) in an area of said surface above the nozzle, so that the surface in said area rises above the grid (<NUM>).