There are several preferred embodiments for practicing this invention. In one embodiment, the apparatus includes an extractor having a flotation member for continuously positioning the extractor within the slurry in the mixing chamber for withdrawing the slurry from the mixing chamber. Another embodiment utilizes a stationary extractor for withdrawing the slurry from the mixing chamber. A yet other embodiment includes an extractor and a continuous level float valve wherein the slurry is maintained at a selected level within the tank by the continuous float valve and the extractor withdraws slurry from the mixing chamber.

2. Description of the Prior Art It is known in the art to utilize a dissolvable or solution grade, granular powdered gypsum in water for use as a fertilizer or soil amendment agent. The mixture resulting from the mixing of the gypsum and water is generally known as a gypsum slurry, gypsum mixture or gypsum solution or gypsum suspension.

It is further known in the art to utilize the gypsum slurry, gypsum mixture or gypsum solution for irrigation or treatment of soil of plants, orchards, vineyards on farms or ranches or other agricultural facilities which grow crops, vegetables and similar vegetable plants or food products or for growing of any kind of plants, flood, crops or the like. Such irrigation or treatment is typically performed on a periodic basis depending upon the soil moisture, moisture penetration in the soil and other such factors. Typically, the gypsum slurry, gypsum mixture or gypsum solution is prepared in apparatus in predetermined volumes using a variety of methods and apparatus for producing a homogeneous mixture of gypsum and water.

In the past. the particulate size of the gypsum was in the order of a sieve size of about 100 mesh and having a gypsum purity based, on a chemical analysis, in the order of 92%.

Such gypsum was vigorously mixed with water to form a slurry. The slurry is then introduced into or injected into an irrigation system or distribution system which applies the dissolved gypsum through outlet nozzles to the food, fiber or plant products and/or soil to be irrigated or treated. The irrigation system may include emitters, spraying devices or other fluid distribution devices.

Such a slurry, mixture or solution sometimes contains particulates of gypsum or other elements that do not completely dissolve and the slurry contains undissolved particulate matter.

Such undissolved particulate matter sometimes clogs or blocks the irrigation apparatus.

United States Patent Nos. 4,812,045 and 4,820,053 disclose an apparatus and method to overcome the above-described clogging or blocking problem due to undissolved particulate matter being present in the gypsum mixture or slurry. United States Patent Nos. 4,812,045 and 4,820,053 teach use of a continuous process and apparatus for preparing a gypsum slurry of water and finely divided high purity gypsum for use in an irrigation system wherein the gypsum and water are mixed by vigorous agitation in a tank or mixing chamber. Means are provided to create a quiescent zone within the tank to enable undissolved particulate matter to settle out of the slurry within the tank the agitation of the slurry within the tank does not interfere with the quiescent zone, the withdrawing of the mixture or the slurry from the tank.

Another known apparatus for dissolving dry material into solution and injecting the same into an irrigation system is taught in United States Patent No. 5,417,491. United States Patent No. 5,417,491 discloses an improvement in the apparatus for injecting controlled amounts of slurry, including soil amendments and fertilizer, into an irrigation system. The apparatus first effectuates batch mixing of a selected soil amendment in the form of a particulate matter in a fluid. The particulate matter is either dissolved or suspended in the fluid to form a slurry, continuously located in an area within the mixing tank in which the admixture displays the greatest or optimum homogeneity. The apparatus continuously withdraws metered amounts of the resulting slurry for injection into an irrigation system over the entire period of an irrigation cycle. The apparatus disclosed in United States Patent No. 5,417,491 uses a floatable extractor for withdrawing the admixture of fluid medium and particulate matter from an area referred to as a quiescent zone. By withdrawing slurry from the upper region of the quiescent zone, the concentration of dissolved particulate matter within the fluid medium is most consistent. A suction tube, operatively connected to the floatable extractor, is used to withdraw the slurry of particulate matter and fluid from the quiescent zone.

United States Patent No. 5,417,491 further discloses that the concentration of the slurry withdrawn by the extractor can be adjusted to accommodate flow. The adjustment of concentration of the slurry to accommodate flow is accomplished through use of a supplemental fluid line extending into the interior of the tank to the interior of the floatable extractor. A supply of fluid, which is under sufficient pressure to permit injection of controlled quantities of fluid, is injected into the extractor to adjust the slurry concentration at the extractor.

It is also known in the art that solution grade gypsum having controlled particulate size and higher purity of gypsum has become available for use with water applications to treat soil.

Such solution grade gypsum is used for applying a gypsum slurry or gypsum mixture to soils by flooding, furrow application, sprinkler system, drip systems and other known irrigation systems. One known solution grade gypsum is sold under the trademark MASTERGYP by Soil Solutions Corporation such solution grade gypsum has a particulate size to pass 100% through a sieve size of 100 mesh and has the following typical analysis: Chemical Analysis Typical Analysis Calcium Sulfate Dihydrate CaS04 2H20 92% Chemical AnalysisTypical Analysis Calcium (Ca) 21.4% Sulfur (S) 17.1% With the availability of the improved solution grade gypsum, the apparatus and method for forming the gypsum slurry or gypsum mixture has become simplified. As such apparatus and method can now be fabricated to produce a more substantially homogeneous mixture of particulate matter, e. g. soluble grade gypsum, and a fluid, e. g. water, to form a slurry.

United States Patent No. 5,628,563 teaches one known method and system for slurry preparation and distribution. United States Patent No. discloses a method and apparatus for supplyinD gypsum slurry of predetermined concentration to a follow-on utilization device, such as an irrigation system network. Slurry of a first higher concentration is prepared in a vessel using a vertically arranged mixer with power and drive components mounted outside the tank and a mixer shaft bearing an impeller and a propeller positioned inside the tank for immersion in the slurry ingredients. Rotation of the impeller and propeller causes the slurry ingredients to flow downwardly in the central region of the vessel, outwardly near the bottom towards the inner wall surfaces, upwardly of the inner wall surfaces towards the top and inwardly to the central region in a cyclic fashion to produce a uniform slurry. The slurry is withdrawn through an outlet in one of the tank walls and mixed with externally supplied water in a mixing chamber, which is separate from an external to the tank, to dilute the slurry to a desired useable concentration. The added water is supplied via an adjustable flow meter to obtain the desired diluted concentration.

United States Patent Numbers 3,365,176; 1,911,644; 1,592,713; and 721,974 disclose mixing vessels having one or more vertically mounted mixing apparatus in the form of mixing paddles for mixing a particulate matter and fluid to form a mixture or slurry of fluid and the particulate matter in suspension.

In about August, 1995, S&R Specialty Equipment Company offered for sale and sold a device referred to as the"S&R FIELD MIXER", which was designed to inject solution grade gypsum and other water soluble nutrients into an irrigation system. The mixing was obtained by use of a vertical stainless steel shaft and mixing propeller, which was a standard, commercially available mixing impeller.

In about the 1995 to 1996 time frame, Agri-Inject, Inc., offered for sale and sold a device referred to as the"CHEMIGATION SYSTEMS", for mixing and applying large volumes of both soluble and non-soluble materials to an irrigation system. The device included a vertically mounted agitator having a propeller, which cooperated with a Series G metering pump to provide precision, accurate and reliable operation and metering of a slurry solution, including a slurry mixture of gypsum for injection into an irrigation system.

In about 1994, AG Pro, Inc., offered for sale and sold a device referred to as the"AG PRO UNIT", which utilized a horizontal mixing agitator having a series of paddles and an extractor interior to the mixing chamber for extracting the slurry from the mixing chamber. The "AG PRO UNIT"included an injection water system, which was connected to the output of the extractor, through a mixing"T"located outside of the mixing chamber, to adjust the density of the slurry output from the tank thereby controlling the density of the particulate matter or gypsum in the slurry prior to injection of the slurry into an irrigation system.

Brawn Mixer, Inc., offers for sale and sells, as a commercially available unit, a stand alone vertical mixing component comprising a vertical paddle agitator referred to as"MODEL BGMF33 THRU 200 GEAR DRIVE". The vertical mixing device included a mixing propeller located at the end of the drive shaft and an intermediate, optional upper impeller, in the form of a pair of opposed extending mixing vanes, located intermediate the mixing propeller at the end of the drive shaft and the drive motor located at the opposite end of the drive shaft None of the known mixing apparatus and injection systems for mixing a mixture of particulate matter and fluid, including a slurry of gypsum and water, utilize an impeller located at the end of the vertical drive shaft wherein the impeller has a plurality of fluid deflecting vanes which generate a bi-directional fluid flow, including a radial flow in a first selected direction and a rapidly moving, highly agitating fluid flow in a second selected direction to thoroughly and vigorously mix the particulate matter and fluid forming a slurry, which slurry is capable of being injected into standard irrigation systems for treating soil, plant material, crops, trees or the like.

SUMMARY OF THE PRESENT INVENTION The present invention discloses a new, novel and unique apparatus for combining particulate matter and a fluid to form a mixture. In the preferred embodiment. the apparatus is used for combining a particulate matter, such as for example a solution grade gypsum. with a fluid, such as for example water to form a gypsum slurry. The resulting gypsum slurry is in the form of a substantially homogeneous mixture comprising water and substantially dissolved, solution grade gypsum. The apparatus includes a tank defining a mixing chamber having an upper section and a lower section for combining particulate matter and a fluid to form a mixture. The apparatus further includes an agitator having an axially extending shaft rotatably mounted in the tank and positioned to extend substantially vertically between the upper section and lower section of the mixing chamber. The agitator includes an impeller which is operatively connected in a substantially perpendicular relationship to the axially extending shaft and is positioned substantially in at least one of the lower section and the impeller. The impeller has flow diversion vanes which, upon rotation of the axially extending shaft member and impeller in a select direction, develops a bi-directional flow of particulate matter and fluid wherein one direction of flow is directed in a path substantially parallel to the upper section of said mixing chamber and wherein the other direction of flow is in a path directed generally perpendicular to form a substantially homogenous mixture comprising the particulate matter and fluid, throughout the mixing chamber.

A novel and unique method of preparing a substantially homogeneous mixture of particulate matter and fluid for distribution through a distribution system is also shown by the present invention. The method comprises the steps of: (a) providing a tank having a mixing chamber including an upper section and a lower section; (b) filing the mixing chamber with a desired amount of fluid; (c) placing a desired amount of particulate matter in the mixing chamber; and (d) mixing the particulate matter and fluid by forming in at least one of the lower section and upper section of the mixing chamber a bi-directional flow of particulate matter and fluid wherein one direction of flow is directed substantially parallel to the upper section of the mixing chamber and the other direction of flow is generally perpendicular to the impeller to form a substantially homogenous mixture comprising particulate matter and fluid throughout the mixing chamber.

The known prior art apparatus and method for preparing in the preferred embodiment, a gypsum slurry of water and finally divided, high purity gypsum for use in irrigation system has certain disadvantages. One disadvantage is that a quiescent zone, such as that disclosed in United States Patent Nos. 4,812,045 and 4,820,053, is required from at least the midsection of the tank to the upper regions thereof for discharge of the slurry so that agitation of the slurry mix and the settling out of particulate matter within the tank does not interfere with an even discharge of the slurry from the tank.

Another disadvantage of the prior art apparatus for dissolving dry material in the solution and for injecting the same into an irrigation system is that a floating extractor includes a deflection member to define the quiescent zone. The floating extractor requires that the concentration of the gypsum slurry be adjusted to accommodate flow by a supply of fluid which is injected, under pressure, for applying a controlled quantity of fluid to the floating extractor which concurrently defines the quiescent zone.

Another disadvantage of the prior art method and system for slurry preparation and distribution is that the structure of the agitator formed from the combination of an impeller and propeller, such as that disclosed in United States Patent No. 5,628,563, causes the slurry ingredients to be restricted into a predetermined material flow pattern. The material flow pattern includes the material being drawn in a substantially exclusively downward direction in the central region of the vessel or tank, then pushed outwardly from the central region along the bottom of the vessel or tank to the inner periphery or walls thereof, then to flow upwardly along substantially planar vertically flow surfaces of the vessel or tank and then inwardly to the central region. This results in the slurry located intermediate the predetermined path between the outside tank walls and the central region of the tank not being exposed to vigorous agitation at all locations within the vessel or tank, particularly in the corner of a rectangular or square tank. Further, a separate mixing chamber, external to the vessel or tank, is used to adjust the concentration of the slurry mixture from a first concentration level to a lower second concentration level.

Therefore, one advantage of the apparatus and method of the present invention for combining particulate matter and a fluid to form a mixture is that a substantially homogeneous mixture is formed throughout the entire mixing chamber.

Another advantage of the present invention is that the apparatus includes an agitator having a novel, unique and improved impeller having bi-directional flow diversion vanes. The impeller, in the preferred embodiment, is operatively connected in a substantially perpendicular relationship to an axially extending shaft which forms the agitator. The impeller has flow diversion vanes which upon rotation of the axially extending shaft member and impeller in a selected direction, develops a bi-directional flow of particulate matter and fluid wherein one direction of flow is directed substantially parallel to the upper section of the mixing chamber and wherein the other direction of flow is generally perpendicular to the impeller to form a substantially homogenous mixture comprising the particulate matter and fluid throughout the mixing chamber.

Another advantage of the present invention is that the agitator may include a propeller- like mixing blade positioned substantially in one of the upper section and the lower section of the mixing chamber and spaced from the impeller to insure vigorous mixing of the mixture or slurry within the entire chamber.

Another advantage of the present invention is that the apparatus may include an extractor for withdrawing the mixture or slurry from the mixing chamber. The extractor may be in the form of an inlet of a conduit, or in the form of a floatable extractor, which may include a floatation member operatively connected to the extractor. Alternatively, the extractor may be in the form of a fixed extractor located in the lower section of the mixing chamber to withdraw the substantially homogeneous slurry or mixture from the mixing chamber.

Another advantage of the present invention is that the apparatus may include a conduit, pipe, hose, housing or an elongated enclosure forming a passageway for transporting the withdrawn slurry or mixture from the mixing chamber to an outlet, external of the tank, to inject the slurry or mixture into a distribution or irrigation system.

Another advantage of the present invention is that a desired amount of fluid can be added to the withdrawn concentrated slurry or mixture within at least one of the extractor and a conduit within the mixing chamber to produce a diluted substantially homogenous slurry or mixture of a predetermined density which is applied to the outlet.

Another advantage of the present invention is that a desired amount of fluid can be added to the withdrawn concentrated slurry or mixture in a conduit external to the mixing chamber to produce a diluted substantially homogenous slurry or mixture of a predetermined density which is applied to the outlet.

Another advantage of the present invention is that the impeller has a plurality of flow diversion vanes which are arranged thereon to produce vigorous mixing action of a particulate matter in a fluid. In one embodiment, the mixing action occurs in a plane which is substantially parallel to the upper section of the mixing chamber and in the form of a rapidly rotating flow motion which is directed along a path which is substantially parallel to an axially extending shaft which drives the impeller. In another embodiment, the mixing action occurs wherein one direction of flow is directed substantially parallel to the upper section of the mixing chamber and wherein the other direction of flow is generally perpendicular to the impeller.

A propeller-like mixing blade may be used concurrently with the impeller to produce a fluid flow substantially parallel to the shaft axis and in a first direction to disrupt or obstruct to cause an agitation in the fluid flow substantially parallel to the shaft axis to improve the mixing of the slurry or mixture by additional agitation or in a second direction to enhance the direction of slurry or mixture flow into and out of the rapid rotary motion developed by the impeller.

The apparatus could also use the propeller-type mixing blade to produce fluid flow in both directions during a mixing cycle to insure vigorous agitation for mixing of the slurry or mixture.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and other advantages of this invention will be apparent from the following description of the preferred embodiment of the invention when considered with the illustrations and accompanying drawings which include the following Figures: Fig. 1 is a top, front and left side perspective view of one embodiment of the present invention comprising an apparatus including a mixing tank, a vertically mounted mixer having an impeller defining mixing vanes for controlling mixing of a slurry, a fixed extractor for extracting the slurry from the mixing tank and a pressure regulator and pump for generating pressure for injecting the slurry into an irrigation system; Fig. 2 is a diagrammatic cross-sectional elevational view of another embodiment of the present invention showing the interior of a tank defining a mixing chamber, an agitator which supports an impeller having bi-directional flow diversion vanes mounted, a propeller-like mixing blade operatively coupled to the axially extending shaft and a floatable extractor for extracting the slurry from the mixing tank; Fig. 3 is a schematic diagram illustrating the fluid flow system for the embodiment illustrated in Fig. 2 and including a water injection system for adding water to a tank having a mixing chamber for adjusting the concentration of the slurry within the tank and concurrently adding water to a floatable extractor for concurrently adjusting the concentration of the slurry at the extractor for controlling the concentration or density of the slurry injected into the irrigation system and a safety float valve for shutting off the water if the slurry level is too high; Fig. 4 is a schematic diagram illustrating the fluid flow system for the yet another embodiment of a mixing apparatus including a water injection system for adding water to a floatable extractor located in a tank having a mixing chamber for adjusting the concentration of the slurry at the extractor for controlling the concentration or density of the slurry injected into the irrigation system; Fig. 5 is a pictorial representation of the drive motor, pump, pulley and vertical drive system for driving an agitator having an impeller and a propeller-like mixing blade ; Fig. 6 is a pictorial representation of one embodiment of the agitator structure wherein the agitator has an axially extending shaft which extends to the upper section and lower section of the tank and is journelled in bearings located in the top and bottom of the tank to permit rotation of the agitator in a second direction wherein the agitator includes an impeller having flow diversion vanes to cause bi-directional flow of the slurry mixture within the mixing chamber and a second spaced propeller-like mixing blade located in the upper chamber to cause vigorous agitation of the slurry mixture in the vicinity of the mixing shaft; Fig. 7 is a pictorial representation of another embodiment of the agitator structure wherein the agitator has an axially extending shaft which extends to the upper section and lower section of the tank and which is joumelled in bearings located in the top and bottom of the tank to permit rotation of the agitator in a selected direction wherein the agitator includes an impeller having flow diversion vanes to cause bi-directional flow of the slurry mixture within the mixing chamber and a pair of spaced separately driven propeller-like mixing blade located in the upper chamber to cause vigorous agitation of the slurry mixture in the vicinity of the mixing shaft and throughout the mixing chamber; Fig. 8 is a pictorial representation of the fluid flow pattern taken along a plane of the impeller which extends substantially parallel to the bottom of the mixing chamber and which is developed by the impeller having bi-directional flow diversion vanes located in a path or plane substantially radial to the vertically extending drive shaft illustrating by means of arrows the bi- directional flow of particulate matter and fluid wherein one direction of flow is directed in a path substantially parallel to the upper section of the mixing chamber and the other direction of flow is directed in a path in a plane generally perpendicular to the bottom of the mixing chamber to form a substantially homogeneous slurry throughout the mixing chamber; Fig. 9 is a pictorial representation of the fluid flow pattern taken along a vertical plane of the drive shaft and impeller which extends substantially perpendicular to the bottom of the mixing chamber wherein the fluid flow is developed by the impeller having bottom, bi- directional flow diversion vanes located in a plane substantially radial to the vertically extending drive shaft and by flow diversion vanes which direct slurry flow in a direction upward from the bottom or lower section of the mixing chamber to the top or upper section of the nixing chamber wherein the slurry flow is illustrated by arrows the bi-directional flow of particulate matter and fluid wherein the vertical slurry flow is directed in a path extending in a direction generally perpendicular from the bottom of the mixing chamber to the top thereof in a generally upward direction to form a substantially homogeneous slurry throughout the mixing chamber; Fig. 10 is a top, front and left side perspective view of an embodiment of a IMPELLER FOR MIXING AND IRRIGATION APPARATUS showing our new impeller design having bottom deflection vanes; Fig. 11 is a bottom, front and left side perspective view of the IMPELLER FOR MIXING AND IRRIGATION APPARATUS of Fig. 10; Fig. 12 is a top, front and left side perspective view of another embodiment of an IMPELLER FOR MIXING AND IRRIGATION APPARATUS showing our new impeller design having bottom deflection vanes and top, radial deflection vanes; Fig. 13 is a bottom, front and left side perspective view of the IMPELLER FOR MIXING AND IRRIGATION APPARATUS of Fig. 12; Fig. 14 is a top, front and left side perspective view of yet another embodiment of an IMPELLER FOR MIXING AND IRRIGATION APPARATUS showing our new impeller design having bottom deflection vanes and top, axial deflection vanes; Fig. 15 is a bottom, front and left side perspective view of the IMPELLER FOR MIXING AND IRRIGATION APPARATUS of Fig. 14; Fig. 16 is a top, front and left side perspective view of still yet another embodiment of an IMPELLER FOR MIXING AND IRRIGATION APPARATUS showing our new impeller design having bottom deflection vanes and top, axial deflection vanes located at the edge of the impeller and top, radial deflection vanes located inwardly therefrom; Fig. 17 is a bottom, front and left side perspective view of the IMPELLER FOR MIXING AND IRRIGATION APPARATUS of Fig. 16; Fig. 18 is a top, front and left side perspective view of yet still another embodiment of an IMPELLER FOR MIXING AND IRRIGATION APPARATUS showing our new impeller design having bottom deflection vanes and top, radial deflection vanes located at the edge of the impeller and top, axial deflection vanes located inwardly therefrom; Fig. 19 is a bottom, front and left side perspective view of the IMPELLER FOR MIXING AND IRRIGATION APPARATUS of Fig. 18; Fig. 20 is a front elevational plan view of the embodiment illustrated in Fig. 19; Fig. 21 is a bottom plan view of the embodiment illustrated in Fig. 19; Fig. 22 is a right, side elevational view of the embodiment illustrated in Fig. 19; Fig. 23 is a left side elevational view of the embodiment illustrated in Fig. 19; Fig. 24 is a top plan view of the embodiment illustrated in Fig. 19; Fig. 25 is a front, top and left perspective view of an extractor having an internal floatation member operatively connected thereto together with a first conduit for withdrawing slurry mixture from a mixing chamber and a second conduit for adding water in the vicinity of the extractor; Fig. 26 (a) is a top pictorial plan view of an extractor having an extraction zone and a separate external floatation member, a low level float shut off valve, a first conduit for withdrawing slurry from the mixing chamber and a second conduit for injecting water into the shroud of the extractor for controlling the concentration of slurry withdrawn from the mixing chamber in the extraction zone of the extractor; Fig. 26 (b) is a partial cross-sectional view taken along section lines 26 (a)-26 (a) of Fig.

26(a); Fig. 27 is a diagrammatical representation of the displacement of the floating extractor illustrated in Fig. 25 from a first position where the slurry has filled the upper section and lower section of the mixing chamber to a second position when the slurry is at a low level in the lower section of the mixing chamber ; Fig. 28 is a pictorial representation of one embodiment of an apparatus partially in cross-section including a tank having a mixing chamber and an agitator having an impeller having bi-directional flow vanes located at the end of the drive shaft in the lower section of the mixing chamber and the agitator has a single propeller-like mixing blade operatively connected to the axially extending shaft and located between the impeller and the top of the mixing chamber and a fixed or stationary extractor having a conduit for adding water in the vicinity of the extractor for adjusting the concentration of the substantially homogeneous slurry before injection into a distribution system; Fig. 29 is a pictorial representation of yet another embodiment of an apparatus partially in cross-section including a tank having a mixing chamber and an agitator having an impeller having bi-directional flow vanes located at the end of the drive shaft in the lower section of the mixing chamber and pair of spaced, fixed, separately driven propeller-like mixing blades located in the upper section of the tank and a fixed or stationary extractor having a first conduit for withdrawing slurry operatively connected to a second conduit at a location before the extractor and within the mixing chamber for adding water in the first conduit and to the withdrawn substantially homogeneous slurry being transported by the first conduit for adjusting the concentration of the substantially homogeneous slurry before an outlet for injection into a distribution system; Fig. 30 is a pictorial representation of still yet another embodiment of an apparatus partially in cross-section including a tank having a mixing chamber and an agitator having an impeller having bi-directional flow vanes located at the end of the drive shaft in the lower section of the mixing chamber and the agitator has a single propeller-like mixing blade operatively connected to the axially extending shaft and located between the impeller and the top of the mixing chamber and a floatable extractor having a conduit for adding water in the vicinity of the extractor for adjusting the concentration of the substantially homogeneous slurry mixture before an outlet for injection into a distribution system; Fig. 31 is a pictorial representation of still yet another embodiment of an apparatus partially in cross-section including a tank having a mixing chamber and an agitator having an impeller having bi-directional flow vanes located at the end of the drive shaft in the lower section of the mixing chamber and the agitator has a single propeller-like mixing blade operatively connected to the axially extending shaft and located between the impeller and the top of the mixing chamber and a floatable extractor having a first conduit for withdrawing slurry operatively connected to a second conduit at a location before the extractor and within the mixing chamber for adding water in the first conduit and to the withdrawn substantially homogeneous slurry being transported by the first conduit for adjusting the concentration of the substantially homogeneous slurry before an outlet for injection into a distribution system; Fig. 32 is a pictorial representation of still yet another embodiment of an apparatus partially in cross-section including a tank having a mixing chamber and an agitator having an impeller having bi-directional flow vanes located at the end of the drive shaft in the lower section of the mixing chamber and the agitator has a single propeller-like mixing blade operatively connected to the axially extending shaft and located between the impeller and the top of the mixing chamber and a floatable extractor has a first conduit for withdrawing slurry operatively connected to a second conduit at a location before the extractor and within the mixing chamber adjacent a side wall of the mixing chamber for adding water in the first conduit and to the withdrawn substantially homogeneous slurry being transported by the first conduit for adjusting the concentration of the substantially homogeneous slurry before an outlet for injection into a distribution system; Fig. 33 is a pictorial representation of still yet another embodiment of an apparatus partially in cross-section including a tank having a mixing chamber and an agitator having an impeller having bi-directional flow vanes located at the end of the drive shaft in the lower section of the mixing chamber and the agitator has a single propeller-like mixing blade operatively connected to the axially extending shaft and located between the impeller and the top of the mixing chamber and a floatable extractor having a first conduit for withdrawing slurry and a second conduit operatively connected to the first conduit at a location before the extractor and on the exterior of the mixing chamber for adding water in the first conduit and to the withdrawn substantially homogeneous slurry being transported by the first conduit for adjusting the concentration of the substantially homogeneous slurry before an outlet for injection into a distribution system; Fig. 34 is a pictorial drawing of an extractor having a shroud and an open end located at an end opposite to the top of the shroud, which extractor may be fixed or floatable, having a first conduit for withdrawing slurry from the upper portion of the extractor shroud and a second conduit for adding or injecting fluid through the top of the shroud for adjusting the concentration of the substantially homogeneous slurry before an outlet for injection into a distribution system; Fig. 35 (a) is a pictorial drawing of an extractor having a shroud and a deflection plate located at an end opposite to the top of the shroud, which extractor may be fixed or floatable, having a first conduit for withdrawing slurry from the upper portion of the extractor shroud and a second conduit for adding or injecting fluid through the side of the shroud for adjusting the concentration of the substantially homogeneous slurry before an outlet for injection into a distribution system; Fig. 35 (b) is a pictorial representation of the extractor illustrated in Fig. 35 (a) wherein the second conduit injects fluid into the first conduit within the extractor; Fig. 36 is a pictorial drawing of an extractor having a shroud and an open end located at an end opposite to the top of the shroud. which extractor may be fixed or floatable, having a first conduit for withdrawing slurry from the upper portion of the extractor shroud and a second conduit for adding or injecting fluid through the open end of the shroud for adjusting the concentration of the substantially homogeneous slurry before an outlet for injection into a distribution system; and Fig. 37 is a pictorial drawing of an extractor having a shroud and a deflection plate located at an end opposite to the top of the shroud, which extractor may be fixed or floatable, having a first conduit for withdrawing slurry from the upper portion of the extractor shroud and a second conduit for adding or injecting fluid through the deflection plate for adjusting the concentration of the substantially homogeneous slurry before an outlet for injection into a distribution system.

DESCRIPTION OF THE PREFERRED EMBODIMENT For purposes of background, a review of mixing systems for preparing and distributing a gypsum slurry into an irrigation system is provided hereinbelow.

The apparatus for preparing a gypsum slurry of water and dissolvable grade, high purity gypsum prepares a gypsum slurry use a continuous mixing process. Typically, the apparatus is in the form of a rectangular tank having a volume in the order of 300 gallons to about 600 gallons. The prior art mixing apparatus typically includes a horizontal paddle mixing system for vigorously mixing the gypsum and water to provide a substantially homogeneous gypsum slurry. Other known prior art apparatus utilize vertically mounted mixing paddles and impellers to provide vigorous agitation of the gypsum slurry within the tank.

A typical mixing apparatus comprises a tank with an agitator. either a horizontally mounted agitator or a vertically mounted agitator, which agitates the gypsum slurry. A pump located external to the tank injects the gypsum slurry into an irrigation system for distribution of the gypsum slurry therethrough for treatment of soil, plants, crops, trees, and the like. An electric motor or a gasoline powered engine is used to drive the agitator and pump.

A standard mixing apparatus may include a float valve which cooperates with an input line to fill the tank with the predetermined quantity of water. The float valve then maintains a constant gypsum inside the tank. The float valve functions to add water to the tank as the gypsum slurry is withdrawn by the pump up and injected into an irrigation system. The agitator continually processes the gypsum slurry by providing vigorous agitation during injection of the gypsum slurry to the irrigation system.

An extractor may be an inlet to a conduit, or may be in the form of an extractor assembly located within the mixing apparatus. The extractor may include a shroud and may be mounted in a fixed position or be floatable within the mixing apparatus. The extractor functions to withdraw gypsum slurry at a controlled concentration from the tank.

In a mixing apparatus utilizing a floating extractor, the tank is filled with a predetermined volume of fluid and the float valve is then shut off to inhibit the adding of additional water through the float valve to the tank. As the gypsum slurry is withdrawn from the tank, the floatable extractor changes position as the level of the gypsum slurry is reduced within the tank.

Another known alternative structure of the mixing apparatus includes the use of a injectable extractor wherein water is added through the shroud into the vicinity of the extractor to vary the concentration of the gypsum solution. In addition, the concentration of the gypsum solution can be varied by use of a float valve for adding water directly to the tank. It is known to control the concentration of the gypsum slurry by controlling the flow rate of fluid which is injected into the extractor.

The utility of the present invention relates to the use of a new, novel, and improved vertically mounted impeller, which forms a bi-directional fluid flow to cause vigorous mixing action of the gypsum slurry within the tank. The improved vertically mounted impeller can be used with any of the above-described mixing apparatus, regardless of the structure thereof in terms of float valves, extractors, injectable extractors, floatable extractors or fixed extractors.

The following descriptions of Figs. applies generally to Figs. 1 through 7 and use the same reference numerals for reference to the same elements.

Fig. 1 illustrates an apparatus shown generally as 40 for combining particulate matter and a fluid to form a slurry or mixture of particulate matter and fluid. In the preferred embodiment, such apparatus is used to mix a dissolvable grade gypsum and water in a tank defining a mixing chamber. A pump is used for withdrawing a homogeneous gypsum slurry at a known concentration from the tank through an extractor and the homogeneous gypsum slurry having an adjusted concentration is then injected into an irrigation system or distribution system.

In Figs. 1 and 2, the apparatus 40 includes a tank 44, which defines a mixing chamber having an upper section 48 and a lower section 50 (both of which are illustrated in Fig. 2) for combining particulate matter and a fluid to form a mixture or slurry. The mixing apparatus 40 further includes an agitator, shown generally as 54 which includes an axially extending shaft 56 rotatably mounted in the tank 44 and positioned to extend substantially vertically between the upper section 48 and the lower section 50 of the tank 44, defining the mixing chamber. The agitator 54 includes an impeller shown generally as 60, which is operatively connected in a substantially perpendicular relationship to the axially extending shaft 56 and positioned substantially in at least one of the lower section 50 and the upper section 48 of the mixing chamber. The embodiment of the impeller shown in Fig. 2 is illustrated in general detail in Fig.

18.

As illustrated in Fig. 2, the axially extending shaft 56 is rotatably mounted in the bottom 66 of tank 44 in a bearing support 70, which permits rotation of the shaft within the lower section 50. The top of the axially extending shaft 56 is mounted in a top bearing member 76 wherein the top 80 of the axially extending shaft 56 extends through the bearing member 74 into operative engagement with a drive pulley 86. The drive pulley 86 is driven by a dual,"V"- shaped drive belts 90. An idler pulley 92 controls the tension within the drive belts 90.

A gear reducer 98 is operatively connected to the drive belts 90 to provide power for rotating the axially extending shaft 56 and the impeller 60. The gear reducer 98 is driven by a separate drive mechanism shown generally as 100, which is in the form of a motor-driven belt 102, which drives the input pulley drive 104 of the gear reducer 98.

As illustrated in Fig. 1, the drive motor 110 is used to drive a pump 114 and the drive belts 102 to drive the shaft 56 and impeller 60.

The impeller 60 may be one of several possible structures which are illustrated in Figs.

10 through 24, which are discussed hereinbelow. The impeller 60 has flow diversion vanes 130 which, upon rotation of the axially extending shaft member 56 and impeller 60 in a selected direction, develop a bi-directional flow of particulate matter and fluid wherein one direction of flow is directed in a path substantially parallel to the upper section 48 of the mixing chamber and wherein the other direction of flow is in a path generally perpendicular to the substantially parallel plane and directed into both the upper section 48 and the lower section 50 to form a substantially homogenous slurry throughout the mixing chamber.

In Fig. 1, water is supplied to the tank 44 through a water intake 134 located at the base of the tank 44 and spaced from the pump 114. Hose 136 applies the water through a sleeve member 140 which, in turn, is operatively connected to conduit 142, illustrated in Fig. 2.

Conduit 142 extends from the sleeve member 140 to either a fixed extractor illustrated by dash lines 148 or a floatable extractor 174. The conduit 142 is operatively connected to a float valve 152, which is operatively connected to a floatable member 160, which controls the operation of the float valve 152 as a function of the level of gypsum slurry in the tank, as sensed by floating member 160. The float valve 152 allows water to enter the floatable extractor 174. The gypsum slurry is withdrawn through conduit 180 (Fig. 2) and hose 164 via seal 146 by pump 114. Selector valve 170 is operable to apply the withdrawn gypsum slurry to outlet hose 176, which injects the gypsum slurry into an irrigation system represented by box 162.

The extractor 148 or 174 ensures that the gypsum/water mixture defining the gypsum slurry is of the desired concentration such that when the gypsum slurry is withdrawn from the extractor, the concentration thereof is at the desired level. The homogeneous gypsum slurry is then injected by the pump 114 into the irrigation system 162. In order to remove undesired materials from the homogeneous gypsum slurry, the gypsum slurry is pumped through a filter 166, which removes foreign debris from the solution and the filtered gypsum slurry is applied through output selector valve 170 to the irrigation system 162. Selector valve 170 can be actuated to apply the withdrawn gypsum slurry to a bypass hose 178 to pump the gypsum slurry back into the mixing chamber.

The output selector valve 170 controls the injecting of the gypsum slurry into the irrigation system 162 in one of two modes, a full output mode and a metered output mode. At the full output mode, the gypsum slurry is injected directly into the irrigation system by the pump 114. In the metered output mode, the flow of the gypsum slurry is restricted by an adjustable orifice located as part of the output selector valve 170.

Referring again to Fig. 2, the conduit 142 is illustrated as being preferably operatively connected to an injectable, floatable extractor 174. The floatable extractor 174 changes its position as a function of the level of the gypsum slurry within the tank. The conduit 142 enters the floatable extractor 174 through the top thereof. The conduit 142 receives water through the sleeve member 140 and applies the water to the floatable extractor 174 through the top thereof.

The pump 114 withdraws the gypsum slurry from the extractor 174 through the conduit 180.

The water is added to the gypsum slurry within the extractor 174 to adjust the concentration thereof prior to the pump 114 extracting the same through the second conduit 180.

For purposes of consistency herein, the conduit used to withdraw slurry from the mixing chamber is referred to herein as the"first conduit". The conduit used for injecting water to adjust the concentration of the slurry is referred to herein as the"second conduit".

Fig. 2 also illustrates that the agitator 54 further includes a propeller-like mixing blade 186 positioned substantially in the upper section 48 of the mixing chamber. The propeller-like mixing blade 186 is spaced from the impeller 60 to drive the slurry in a direction opposite to the generally perpendicular path of fluid flow developed by the impeller 60 to cause a mixing action along a path which is substantially parallel to the axially extending elongated shaft 56.

Fig. 3 illustrates schematically the fluid flow for the floating extractor. The tank 44 is filled by means of an auxiliary water inlet 192 and hose 136, as described hereinbefore, which fills the tank through an internal fill float valve which limits the level of water within the mixing chamber. In addition, auxiliary water line 192 applies water to a hose 242, which applies water to an internal low level float valve to provide the capability of adding water if the slurry level becomes too low.

The main water line 194 applies water through a filter 190 to a select valve 220. Select valve 220 has an output hose 234, which applies water to an in-line flow meter 238 through hose 236 and to an electronic flow meter 238 through hose 240. A three-way valve 242 can be set to apply water either from the in-line flow meter 238 shunt path or the electronic flow meter 238 shunt path to conduit 232 which is operatively connected to the first conduit to add or inject water to the injectable extractor 174 illustrated in Fig. 2.

The pump 114 is operatively connected to hose 164 through a three-way valve 244 and filters 208 to apply suction to the extractor and to withdraw slurry from the mixing chamber.

The output from pump 114 appears on hose 212, which then applies the same to an output selector valve 170. The selector valve 170 is operatively connected to hose 176 to apply the withdrawn slurry to the irrigation system 162. Selector valve 170 can be operated to apply the withdrawn slurry to bypass hose 178 and back into the mixing chamber.

Fig. 4 is a schematic diagram illustrating the hose and pump structure for the floating extractor illustrated in Fig. 2. Water is applied by water line 194 through filter 190 and hose 136 to the tank 44. Also, line 194 applies water to the selector valve 220. Selector valve 220 applies water through hose 234 to an electronic flow metering system 228, which in turn applies water to hose 232. Hose 232 is connected to the second conduit and injectable floating extractor. The pump 114 withdraws the homogeneous gypsum slurry through hose 164, three- way valve 244 and filter 208 and applies the gypsum slurry through output selector valve 170 to output hose 172. Alternatively, selector valve 170 can be operated to apply the withdrawn slurry to bypass hose 178 for pumping back into the mixing chamber.

In Fig. 3, the tank 44 is filled with a desired volume of water and a preselected weight of gypsum is added to the tank 44. the vertical drive agitator, as illustrated in Fig. 2, vigorously agitates the water/gypsum mixture to form a homogeneous gypsum slurry. The concentration of the withdrawn gypsum slurry is adjusted by controlling the amount of water passing through the electronic flow metering system 228, through hose 232, into the conduit 180 and into the injectable extractor 174. The schematic diagram of Fig. 3 would be applicable to both a fixed extractor and a floatable extractor which is in the form of an injectable extractor.

Fig. 5 is a pictorial representation of how a single motor 300 can be used to both provide power for driving the vertically mounted agitator 54 and the pump 114. The motor 300 applies power to a drive pulley 302, which drives a belt 304, which, in turn, powers a drive pulley 310. The drive pulley applies a drive force through drive shaft 316 through pump 114.

Pump 114 also includes a driven shaft 320, which is operatively connected to a second driven pulley 322. Driven pulley 322 drives belt 102 to drive pulley 104 of the gear reducer 98. The gear reducer 98, through drive belts 90, idler pulley 92 and drive pulley 86 drives the vertically mounted agitator 54, as described hereinabove with respect to Fig. 2.

Fig. 6 is a pictorial representation of the structural relationship between the agitator 54 and the outerwalls 340 of tank 44. The agitator includes an axially extending shaft 56 having a first end 342 and second end 344. The first end 342 extends through the sleeve bearing 76 and extends external to the outerwall 340 to be operatively connected to the drive pulley 86. The other second end 344 of the axially extending shaft 56 terminates in bearing 70 which operatively mounted to the bottom 348 of tank 44. The sleeve bearing 76 and the floor bearing 70 permit the axially extending shaft 56 to be rotated in a selected direction which, in the preferred location, is a counter-clockwise direction as shown by arrows 350. The impeller 60 is preferably operatively connected to the axially extending shaft 56 so as to be located in the lower section of the mixing chamber illustrated as lower section 50 in Fig. 2. The propeller- like mixing blade 74 is operatively connected to the axially extending shaft 56 and is located, in the preferred embodiment, in the upper section 48 of the tank 44. When the axially extending shaft 56 is driven in a counter-clockwise direction by drive pulley 86, both the impeller 60 and the propeller-like mixing blade 74 are likewise driven in a counter-clockwise direction. The impeller 60 develops a bi-directional flow in two directions, one of which is a path substantially parallel to the upper section 48 of the tank 44 and the second direction is in a path generally perpendicular to the substantial parallel path and into both the upper section 48 and lower section 50. The propeller-like mixing blade 74 drives the slurry in a direction opposite the direction of the generally perpendicular path of the slurry to cause a vigorous mixing action both upwardly and downwardly along a path substantially parallel to the axially extending shaft 56.

Fig. 7 pictorially represents a different structure of the vertically mounted agitator 54 from the structure depicted in Fig. 6. The agitator comprising the axially extending shaft 56, the driven pulley 86 and the impeller 60 is substantially the same structure as illustrated in Fig.

6.

In Fig. 7, two separate spaced vertically mounted propeller-like mixing blade assemblies shown generally as 360 are mounted in the outerwall 340 of tank 44. Each vertically mounted propeller-like mixing blade assembly 360 includes a drive pulley 362, a drive shaft 370 and a propeller-like mixing blade 74. In the structure illustrated in Fig. 7, the agitator 54 can be driven in a counter-clockwise direction as shown by arrow 350. However, the propeller-like mixing blade assemblies 360 can be driven in either the clockwise or counter- clockwise direction. In the preferred embodiment, the propeller-like mixing blade assemblies 360 are driven in a counter-clockwise direction as shown by arrows 374. The propeller-like mixing blade assemblies function to break-up what would otherwise be a downward flow of gypsum solution from the outerwall 340, which defines the top of the tank 44, downward toward the outerwall 348, which defines the bottom of the tank 44. Such a structure provides vigorous mixing of the gypsum/water to form a homogeneous slurry.

Fig. 8 illustrates in a pictorial representation the fluid flow pattern taken along a plane of the impeller 60 which extends substantially parallel to the bottom 348 of the mixing chamber of tank 44.

Fig. 8 illustrates that the impeller 60 is in the form of an elongated member 388, which is illustrated by a dash line, and has a pair of ends shown generally as 390 and 392. A deflection vane 396 is located at each end of and bottom surface of the elongated member 388.

A flow pattern is developed by the bi-directional flow diversion vanes 396. The flow pattern is located in a plane substantially radial to the vertically extending drive shaft 56. Arrows 394 illustrate the flow of particulate matter and fluid from deflection vanes 396. The direction of flow developed by deflection vanes 396 is primarily directed in a plane substantially parallel to the upper section 48 of the mixing chamber in tank 44 which concurrently, in the embodiment illustrated in Fig. 8, is substantially parallel with the bottom 348 of tank 44. A portion of the flow is directed in a path generally perpendicular to the bottom of the tank. The fluid flow is primarily directed in a plane substantially parallel to the both, keeping the corners of the rectangular tank free of particulate material build-up.

The top surface of the elongated member 388 has at least one radial deflection vane 400 positioned thereon and oriented relative to the elongated member 388 whereupon rotation of the elongated member in a selected direction, such as for example counter-clockwise as illustrated by arrow 350, drives the radial deflection vanes 396 into the slurry to deflect the slurry along a path substantially radially and outwardly as shown by arrows 404.

The elongated member 388 includes at least one axial deflection vane 408 positioned on the top surface of the elongated member 388 and at the ends thereof and located to be inward of the deflection vanes 400. The axial deflection vane 408, upon rotation of the elongated member, drives the axial deflection vane 408 into the slurry to deflect the slurry along a path substantially perpendicular to and generally upwardly and outwardly from the elongated member 388, as shown by arrows 410.

Thus, the other direction of flow illustrated by the flow pattern of Fig. 8 is directed along a path which is generally perpendicular to the bottom, as shown by arrows 410, to form a substantially homogeneous slurry throughout the mixing chamber.

Fig. 9 illustrates in a pictorial representation the fluid flow pattern taken along a vertical plane of the axially extending shaft 56 and the impeller 60, which extends substantially perpendicular to the bottom 348 of the mixing chamber of tank 44. This is shown by dashed line 352. The fluid flow is developed by the impeller 60 wherein the bi-directional flow diversion vanes 396 located in a plane substantially radial to the vertically extending drive shaft 56 and by radial flow diversion vanes 400 and axial deflecting vanes 408, which direct the slurry in a direction upward from the bottom 348 or lower section 50 of the mixing chamber in tank 44 or towards the outerwall 340 which defines the top of the tank 44 or towards the upper section 48 of the mixing chamber in tank 44. The slurry flow is illustrated by arrows 422 which flows along the outerwalls of the tank 44, across the outerwall 340 defining the top of tank 44 and towards the axially extending shaft 56. A portion of the slurry flow shown by arrows 426 is directed slightly radially from the axis 352, as shown by arrows 430.

Concurrently, the flow shown by arrows 426 intersects with the slurry flow developed by axial deflection vanes 408, which is illustrated by arrows 428. The slurry flow represented by arrows 426 and 428 intersect along the path which extends substantially parallel to the axially extending shaft 56 to cause the slurry to be deflected towards the outer outerwall of the tank 44, as illustrated by arrows 430.

Some rotary motion is developed around the axis 352, as illustrated by arrows 352.

The embodiment of the impeller illustrated in Figs. 12 and 13 generate a rapid rotary flow motion around axis 352. The flow pattern can be varied by various impeller designs illustrated and discussed herein below in Figs. 10 through 24.

As a result of the interaction between the deflection vanes 396, radial deflection vanes 400 and axial deflection vanes 408, the bi-directional flow of particulate matter and fluid is directed in a path generally perpendicular to the bottom 348. The above-described flow pattern provides vigorous mixing action throughout the mixing chamber of tank 44 to form a substantially homogeneous slurry throughout the mixing chamber of tank 44.

Figs. 10 through 24 illustrate various embodiments for agitator 56 which can be used for mixing particulate matter in a fluid. The agitator 56 has the impeller 60 operatively fixedly connected thereto for rotation therewith in a selected direction.

In Figs. 10 and 11, the impeller 60 has an elongated member 420 which defines a central area 424, a first surface 426, an opposed second surface 430 and a pair of ends 434 and 436. Each of the pair of ends 434 and 436 has formed on the first surface 426 a first flow diversion vane 440 and a second flow diversion vane 442. The first flow diversion vane 440 has a leading edge 446 and a trailing edge 448, wherein the flow diversion vane 440 forms an arcuate shaped surface 452 extending in a direction towards the central area 424 of the elongated member 420 of impeller 60. The second flow diversion vane 442 is spaced a predetermined distance from the first flow diversion vane 440 and has a leading edge 460 and a trailing edge 462. The flow diversion vane 442 forms an arcuate shaped surface 466 extending in a direction away from the center area 424. When the impeller 60 is rotated in a selected direction, which in the preferred embodiment is counter-clockwise and in a fluid being capable of developing a bi-directional flow motion, a bi-directional flow of a homogeneous mixture formed of a particulate matter and fluid is driven in a bi-directional flow pattern as described above. One direction of flow is substantially parallel to the impeller 60 and the other direction of flow is in a path generally perpendicular to the central area 424 of the impeller 60. In this embodiment, the fluid flow, generally upward along the generally perpendicular path, is substantially less than the fluid flow around a path substantially parallel to the impeller.

The central area 424 includes a raised boss having an opening extending therethrough shown generally as 464, which is used for fixedly operatively connecting the impeller 60 to an axially extending shaft, such as shaft 56 illustrated in Fig. 2.

Figs. 12 and 13 illustrate another embodiment of an impeller 60 which includes additional flow diversion vanes and which are added onto the embodiment illustrated in Figs.

10 and 11.

In Figs. 12 and 13, third flow diversion vanes 470 are located on the second surface 430 and located above the first flow diversion vane 440 and the second flow diversion vane 442. Each of the third flow diversion vanes 470 has a leading edge and a trailing edge wherein the flow diversion vane forms an arcuate shaped surface extending in a direction away from said central area 424 of the impeller 60 in a similar manner as that described above with respect to Figs. 10 and 11.

In addition, the impeller 60 illustrated in Figs. 12 and 13 further includes a fourth flow diversion vane 472 located on the second surface and located above the other of the first flow diversion vane 440 and the second flow diversion vane 442. Each of the fourth flow diversion vanes has a leading edge and a trailing edge wherein the flow diversion vane forms an arcuate shaped surface extending in a direction away from the central area 424 of the impeller 60 in a similar manner as that described above with respect to Figs. 10 and 11.

The embodiment of the impeller illustrated in Figs. 12 and 13 form a rapid rotary fluid motion around the axis of the impeller.

In Figs. 14 and 15, a yet another embodiment of the impeller 60 having a different structure than that illustrated in Figs. 10 and 11 are shown. In Figs. 14 and 15, the second surface 430 has a single, relatively large, third flow diversion vane in the form of an axial deflection vane 480. The axial deflection vane 480 is positioned inwardly from the first diversion vane 440 and the second diversion vane 442. Upon rotation of the elongated member 420, in a selected direction, which in the preferred embodiment is in a counter-clockwise direction, the elongated member 420 drives the axial deflection vane 480 into the slurry to deflect the slurry along a path substantially perpendicular to and generally upwardly and outwardly from the elongated member 420. In the embodiment of the impeller illustrated in Figs. 14 and 15, the generally perpendicular fluid flow relative to the tank bottom, extends generally upwardly from the bottom of the mixing chamber to the top thereof and intersects with any downward fluid flow to cause the desired mixing action.

Figs. 16 and 17 illustrate yet another embodiment of impeller 60 illustrated in Figs. 10 and 11. The first deflection vane 440 and the second deflection vane 442 are located on the first surface 426. On the second surface 430, the third deflection vane is in the form of an axial deflection vane 480 having located adjacent thereto the fourth deflection vane in the form of a radial deflection vane 470. The axial deflection vane 480 and radial deflection vane 470 deflect the slurry as described hereinbefore to form a bi-directional fluid motion.

In the embodiment of the impeller of Figs. 16 and 17, the fluid flow is directed along both the parallel and perpendicular paths, as described hereinbefore.

Figs. 18 and 19 illustrate still yet another embodiment of impeller 60 illustrated in Figs.

10 and 11. The first deflection vane 440 and the second deflection vane 442 are located on the first surface 426. On the second surface 430, the third deflection vane is in the form of an radial deflection vane 470 having located adjacent thereto the fourth deflection vane in the form of a the axial deflection vane 480. The axial deflection vane 480 and radial deflection vane 470 deflect the slurry as described hereinbefore to form a bi-directional fluid motion.

Figs. 20 through 24 are based on the impeller 60 illustrated in Figs. 18 and 19 and illustrate various elevational and plane views of the impeller 60. The elongated member 424 has the first and second deflection vanes 442 located on the first or bottom surface thereof. The top or second surface of the impeller 60 have a third deflection vane 470 in the form of a radial deflection vane and a fourth deflection vane 480 in the form of an axial deflection vane.

Fig. 20 is a front elevational view of the above-described embodiment illustrated in Figs. 18 and 19 and clearly shows the relationship between the deflection vane 442, the radial deflection vane 470 and the axial deflection vane 480.

In the bottom view of Fig. 21, the elongated member 424 includes the first and second deflection vanes 440 and 442. In the right side elevational view of Fig. 22 and the left side elevational view of Fig. 23, the second deflection vane 442 is positioned opposite to the axial deflection vane 470.

In the top plan view of Fig. 24, the relationship between the radial deflection vane 470 and axial deflection vane 480, each of which are located at the spaced opposed ends of elongated member 424, is shown, it being noted that the first and second deflection vanes 440 and 442 located on the first surface 426 are located at the outermost edge of the elongated member 424. In the embodiment of the impeller illustrated in Figs. 18 through 24, the fluid flow is directed along both the parallel and perpendicular paths, as described hereinbefore.

Fig. 25 illustrates an extractor 174 having an interior float material shown by dashed lines 488 for withdrawing slurry from the mixing chamber in tank 44, as described hereinbefore in connection with Fig. 2. In the embodiment illustrated in Fig. 25, the extractor 174 has a shroud 484 which terminates in an open bottom 490 and closed top 486 which is spaced from the open bottom 490. The interior of the shroud 484 defines a hollowed out central area which forms an extraction zone from which a selected concentration of homogeneous slurry can be extracted or withdrawn from the tank 44.

Slurry is withdrawn through the first conduit 492. Water is injected into the extraction zone, defined by shroud 484, by second conduit 498.

Fig. 26 (a) illustrates another embodiment of an extractor assembly 500 having a shroud 502 operatively connected to a filling conduit 504 to fill the tank by a fill line or means of a float valve 501. A separate floatation member 506 is operatively connected to the shroud 502.

A conduit 508 is operatively connected to the shroud 502 to apply water therein for adjusting the concentration of the slurry in the extraction zone. A conduit 510 is operatively connected to the extraction 502 to withdraw the homogeneous slurry from the top of the slurry extraction zone located within the hollow of the shroud 502. By controlling or metering the volume of water added through the first conduit 508 to the hollowed out central area, the concentration of the homogeneous slurry can be adjusted as the same is withdrawn by conduit 512.

Fig. 26 (b) illustrates in a cross-section the extractor assembly 500 and the shroud 502 which defines the slurry extraction zone shown as 514. The fill conduit 504 is used to fill the tank through the shroud 502 and the water level is controlled by float valve 501.

Fig. 27 illustrates pictorially the floatable, injectable extractor 174 when mounted within the interior of tank 44. When the tank 44 is filled with slurry and as the slurry is thoroughly mixed using the vertically mounted agitator as described hereinbefore, the extractor 174 floats within the gypsum slurry and maintains a position as illustrated by the solid lines in Fig. 27.

As the gypsum slurry is removed from the tank 44 and no additional water is added to the tank 44 through a floatation valve 152 as illustrated in Fig. 2, the level of the gypsum slurry will decrease bringing the level of the slurry towards the outerwall 348 defining the bottom of tank 44 which, in turn, causes the extractor 174', as shown by the dashed lines showing the lowered position of the extractor 174, to move the same towards the bottom of tank 44. The extractor 174 is adapted to have withdrawn substantially homogeneous slurry passed through the first conduit 492 for transportation to the outlet.

As illustrated in Figs. 25 and 27, the extractor 174 includes a member, in the form of the second conduit 498, for adding a controlled volume of water into the substantially homogeneous slurry in the vicinity of the extractor 174 for controlling or adjusting the concentration of gypsum per unit volume of slurry withdraw from the mixing chamber in tank 44.

As illustrated in Figs. 28 through 33, the method or process for adjusting the concentration of the gypsum solution and the method for withdrawing a selected concentration of gypsum solution can take a number of different structures. In addition, the actual structure of the apparatus for performing the methods or processes described below in connection with Figs. 28 through 33 can be fabricated as necessary depending upon the application.

The extractor for withdrawing slurry from the mixing chamber can be formed of a wide variety of structures. The simplest extractor can be the end of a hose. The extractor can be fixed or floatable. The extractor can be in the form of an assembly having a shroud, can be fixed, can be floatable with internal or external floatation members, or be formed of any similar structures or combination of the extractors, as described herein. The extractor may have an extraction zone, a quiescent zone, a deflection plate or any combination thereof. The term "extractor"as used herein is used in its broadest sense.

In Fig. 28, the tank comprising the mixing chamber is shown as 44 and includes an agitator shown generally as 54 having an impeller 130 and propeller-type mixing vane 186 as described hereinbefore. The agitator 54 performs the function or step of vigorously mixing the gypsum solution with an impeller capable of forming a bi-directional fluid flow, as described hereinbefore, is used as shown in Fig. 28. Fig. 28 also includes a fixed extractor 174 which is located in the lower section of the mixing chamber. The extractor includes a first conduit 492 for withdrawing gypsum slurry from an extraction zone 550 of extractor 174.

A second conduit 498 is operatively connected to the extractor 174 and passes through the shroud thereof, which shroud is illustrated as shroud 484 illustrated in Fig. 26. The second conduit 498 adds a predetermined quantity of fluid, which in the preferred embodiment is water, to the gypsum solution located in extraction zone 550 to adjust the concentration of the gypsum solution as the same is withdrawn through first conduit 492.

Fig. 29 illustrates another embodiment of an apparatus for practicing this invention which includes the tank 44 as the mixing chamber, the agitator 54 having the impeller 130 and a pair of separately driven propeller-like mixing blades 360 to provide the mixing action within the tank 44. Fig. 29 differs from Fig. 28 in that the fixed extractor 174 has the first conduit 492 passing through the shroud to withdraw gypsum solution from extraction zone 550 in the same manner as described above with respect to Fig. 28. However, a second conduit 498 is operatively connected to the first conduit 492 in the vicinity of the extractor 174 through a"T" shaped mixing device or diluting chamber 560. The fluid or water being added to the withdrawn gypsum solution is added at the diluting chamber 560 to adjust the concentration of the gypsum solution after the same has been withdrawn from the extraction zone 550.

It is envisioned that the structures illustrated in Figs. 28 and 29 and described hereinabove, would function equally well with a floating extractor rather than a fixed extractor, as described below.

In Fig. 30, the tank 44 utilizes an agitator 54, impeller 130 and propeller-like mixing blade 186, as described in connection with Fig. 28 above. However, the extractor 174, as illustrated in Fig. 30, can be either a fixed extractor 174 or a floatable extractor 174. The structure of a floatable extractor has been discussed earlier in connection with Fig. 27.

In Fig. 30, the extractor 174 defines the extraction zone 550 and the first conduit 492, which is used to extract or withdraw the different solutions, passes through the top of extractor 174, as described earlier in connection with Fig. 26. The second conduit 498 is likewise operatively connected to the extractor 174 through the top thereof. The fluid or water added to the extraction zone 550 dilutes or adjusts the concentration of the of the gypsum slurry within the extractor 174 prior to the withdrawal of the same through the first conduit 492.

Fig. 31 illustrates an apparatus which is similar in structure to that described in Fig. 30 above, and includes a floatable extractor 174. The first conduit 492 extracts the gypsum solution from the extraction zone 550 in the same manner as described above with respect to Fig. 29. The second conduit 498 adds fluid or water to the withdrawn gypsum slurry through dilution chamber 560, which is located near extractor 174 in a manner similar to that described above for Fig. 29.

Figs. 32 and 33 illustrate an apparatus which is similar to that illustrated in Fig. 31 and includes a floatable extractor 174. In Fig. 32, the dilution chamber 560 is located interior to the mixing chamber of tank 44, but adjacent an outside wall 562.

Fig. 33 illustrates that the dilution chamber 560 can be located exterior to the mixing chamber defined by tank 44 and outside of the sidewall 562.

In certain applications, it may be desirable to use extractors of various different structures for controlling the adjustment of the concentration of gypsum solution within an extractor. The extractor may be a fixed extractor or a floatable extractor and may include a deflection plate to reduce, block, shelter or protect the opening into and defining the extraction zone within the interior or hollowed-out central area of the extractor.

Figs. 34 through 37 illustrate certain of the variations for the structure of such extractors. In Figs. 34 through 37, the extractor is generally shown by arrow 600 and includes a shroud 602 having an opening 604 which defines one end of a shroud 602 and a closed top 605 which defines the other end of a shroud 602. In each of the structures illustrated in Figs.

34 through 37, a first conduit 610 passes through the top 606 and into an extraction zone 598 to withdraw gypsum solution therefrom. Each of the first conduit 610 include an elongated section 606, which extends generally into the upper portion of the extraction zone 598 such that the gypsum solution can be withdrawn from inlet 606. Generally, the gypsum solution at this location in the extraction zone 598 is homogeneous of the desired concentration. The concentration of the gypsum solution within extraction zone 598 can be adjusted by passing additional fluid through second conduit 614 and inlet 612, which likewise communicates with the upper portion of the extraction zone 598, such that the additional fluid is added to and mixes with the gypsum solution in extraction zone 598 to adjust the concentration thereof concurrently with the withdrawal step being performed by orifice 606.

Fig. 35 (a) illustrates an alternate structure wherein the second conduit 614 communicates with extraction zone 598 by passing through the shroud 602 placing the inlet 612 further into the extraction zone 598. Fig. 35 (a) also illustrates the location of a deflection plate 616 which is supported by support 618 from extractor 600. Deflection plate 616 essentially protects the opening 604, thereby limiting the magnitude of the vigorous action developed within the tank 44 by the agitator 54 from reaching the extraction zone 598.

Fig. 36 (b) pictorially illustrates that the first conduit 610 can have the second conduit 614 operatively connected thereto within the extractor 600 through a dilution chamber 560 to adjust the concentration of the withdrawn slurry immediately after the slurry is withdrawn from the extraction zone 598.

Fig. 36 illustrates that the second conduit 614 can be positioned within the extractor 600 to pass through the opening 604 and that an extended section 620 is provided to position the inlet 612 toward the interior of the extraction zone 598.

Fig. 37 illustrates a structure similar to that illustrated in Fig. 35 (a) wherein the second conduit 614 passes through and is supported by the deflection plate 616 such that the extended section 620 positions the inlet 612 within the extraction zone 598.

It is envisioned that the use of the novel, unique and improved impeller for developing a bi-directional flow of particulate matter and fluid produces a homogeneous mixture of the particulate matter and fluid in the form of a solution. In the preferred embodiment, the particulate matter is preferably a high-grade, soluble gypsum. However, a lesser grade, soluble gypsum can be utilized wherein the particulate matter of the gypsum is larger than the size thereof typically present in a high-grade, soluble gypsum.

In addition, the novel and unique impeller, as disclosed herein, can be used with any type of extractor or with any combination of fixed extractors or floatable extractors as described hereinbefore. In addition, it is further envisioned that water level valves and similar known fluid level control devices can be used to adjust the concentration of the gypsum within the mixing chamber of a tank in addition to or in lieu of adding additional fluid to the extractor or to the gypsum solution withdrawn from the extractor. In the latter structure, a dilution chamber is typically used to perform the step of adjusting the concentration of the gypsum solution and the dilution chamber can be located anywhere between the inlet to the irrigation or distribution system, on one hand, and before the extractor, on the other hand. Thus, depending on the application, the quality of the gypsum used to form the gypsum solution and other factors, it is envisioned and anticipated that an agitator, including any one or more of the species of the impellers disclosed herein, will result in a controlled concentration of homogeneous solution or gypsum solution being delivered at the output of the tank defining the mixing chamber.

Any variations in the structure of the agitator, including the impeller, location of the various components or apparatus used for mixing the solution or for controlling the concentration of the solution mixed within the mixing chamber of the tank are anticipated to be within the scope and teachings of the present invention.