WO1999026719A1

WO1999026719A1 - Mixing apparatus and method

Info

Publication number: WO1999026719A1
Application number: PCT/US1998/025084
Authority: WO
Inventors: Craig S. Hornung; Charles J. Hornung
Original assignee: Soil Solutions Corporation
Priority date: 1997-11-24
Filing date: 1998-11-23
Publication date: 1999-06-03
Also published as: AU1702099A

Abstract

Apparatus for mixing gypsum and water forming a slurry is shown. The apparatus comprises a tank defining a mixing chamber having an upper section and an opposed lower section. The apparatus includes an agitator having an elongated shaft member rotatably mounted in the tank and positioned to extend substantially vertically between the upper section and the lower section of the mixing chamber. The agitator includes an impeller operatively connected in a substantially perpendicular relationship to the elongated shaft member and positioned substantially in the lower section of the mixing chamber. The impeller has flow diversion vanes. The flow diversion vanes, upon rotation impeller in a selected direction, develops a bi-directional flow, one in a direction substantially parallel to the impeller and the other direction of flow is generally perpendicular to the impeller, mixing the gypsum and water in the mixing chamber to form a substantially homogeneous slurry. An extractor, positioned in the mixing chamber, is operatively coupled to an outlet to form a passageway therebetween for withdrawing the substantially homogeneous slurry from the tank. A method for mixing gypsum and water to form a substantially homogeneous slurry is also shown.

Description

MIXING APPARATUS AND METHOD

1 Field of the Invention

This invention relates to a mixing apparatus and a method. In one example this is a gypsum mixing apparatus including an impeller having bi-directional flow diversion vanes and method This invention relates to an apparatus for combining particulate matter and a fluid forming a mixture and more particularly relates to an apparatus for mixing gypsum and water wherein the apparatus has a substantially vertically extending impeller for developing bidirectional flow to form a substantially homogenous slurry through the entire mixing chamber. 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 with 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 withm the tank by the continuous float valve and the extractor withdraws slurry from the mixing chamber.

2. Descπption of the Pπor Art It is known m 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 m 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 agπcultural 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 peπodic 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 m apparatus m predetermined volumes using a vaπety 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 puπty 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 lrπgation system or distπbution system which applies the dissolved gypsum through outlet nozzles to the food, fiber or plant products and/or soil to be irπgated 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 irπgation apparatus.

United States Patent Nos. 4,812,045 and 4,820,053 disclose an apparatus and method to overcome the above-descπbed 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 prepaπng a gypsum slurry of water and finely divided high purity gypsum for use in an irrigation system wherem the gypsum and water are mixed by vigorous agitation m a tank or mixing chamber. Means are provided to create a quiescent zone withm the tank to enable undissolved particulate matter to settle out of the slurry within the tank the agitation of the slurry withm 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 mateπal 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 the form of a particulate matter in a fluid. The particulate matter is either dissolved or suspended m the fluid to form a slurry, continuously located m an area withm 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 peπod of an lrπgation 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 withm 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 mteπor of the tank to the mtenor 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 m the art that solution grade gypsum having controlled particulate size and higher puπty 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, spπnkler system, dπp systems and other known lrπgation 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:

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 fabπcated 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 distπbution. United States Patent No. 5,628,563 discloses a method and apparatus for supplying gypsum slurry of predetermined concentration to a follow-on utilization device, such as an lrπgation system network. Slurry of a first higher concentration is prepared in a vessel using a vertically arranged mixer with power and dπve components mounted outside the tank and a mixer shaft beaπng an impeller and a propeller positioned inside the tank for immersion m the slurry mgredients. Rotation of the impeller and propeller causes the slurry ingredients to flow downwardly m 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 m 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 m 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 nutπents mto an imgation 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, Agπ-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 mateπals to an imgation system. The device included a vertically mounted agitator having a propeller, which cooperated with a Seπes G meteπng pump to provide precision, accurate and reliable operation and meteπng 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 hoπzontal mixing agitator having a seπes of paddles and an extractor mteπor 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 pπor to injection of the slurry into an imgation system.

Brawn Mixer, Inc., offers for sale and sells, as a commercially available unit, a stand alone vertical mixing component compnsmg a vertical paddle agitator referred to as "MODEL BGMF33 THRU 200 GEAR DRIVE". The vertical mixing device mcluded a mixing propeller located at the end of the dπve 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 dπve shaft and the dπve motor located at the opposite end of the dπve 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 dnve shaft wherem the impeller has a plurality of fluid deflecting vanes which generate a bi-directional fluid flow, including a radial flow m a first selected direction and a rapidly moving, highly agitating fluid flow m a second selected direction to thoroughly and vigorously mix the paniculate matter and fluid forming a slurry, which slurry is capable of being injected mto standard imgation systems for treating soil, plant mateπal, 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 prefeπed 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 compnsmg 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 m a substantially perpendicular relationship to the axially extending shaft and is positioned substantially m 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 m 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 compnsmg the particulate matter and fluid, throughout the mixing chamber

A novel and unique method of prepanng a substantially homogeneous mixture of particulate matter and fluid for distπbution through a distribution system is also shown by the present invention The method compπses 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) placmg 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 compnsmg particulate matter and fluid throughout the mixing chamber.

The known pnor art apparatus and method for prepanng in the preferred embodiment, a gypsum slurry of water and finally divided, high puπty gypsum for use in imgation 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 withm the tank does not interfere with an even discharge of the slurry from the tank.

Another disadvantage of the pnor art apparatus for dissolving dry mateπal in the solution and for injecting the same mto an imgation 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 pnor art method and system for slurry preparation and distπbution is that the structure of the agitator formed from the combination of an impeller and

propeller, such as that disclosed m United States Patent No. 5,628,563, causes the slurry mgredients to be restncted into a predetermined mateπal flow pattern. The matenal flow pattern includes the matenal 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 penphery 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 prefeπed 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 wherem the other direction of flow is generally perpendicular to the impeller to form a substantially homogenous mixture compnsmg the particulate matter and fluid throughout the mixing chamber.

Another advantage of the present invention is that the agitator may include a propellerlike 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 withm the entire chamber.

Another advantage of the present mvention is that the apparatus may mclude 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 distπbution or imgation system

Another advantage of the present invention is that a desired amount of fluid can be added to the withdrawn concentrated slurry or mixture withm at least one of the extractor and a conduit with 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 m 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 m a fluid. In one embodiment, the mixing action occurs m a plane which is substantially parallel to the upper section of the mixing chamber and m the form of a rapidly rotating flow motion which is directed along a path which is substantially parallel to an axially extending shaft which dπves the impeller. In another embodiment, the mixing action occurs wherem 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 m a first direction to disrupt or obstruct to cause an agitation m 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 duπng 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 descπption 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 compnsmg 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 mto an imgation system;

Fig. 2 is a diagrammatic cross-sectional elevational view of another embodiment of the present invention showing the mteπor 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 withm 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 imgation 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 imgation system;

Fig. 5 is a pictoπal representation of the dnve motor, pump, pulley and vertical dπve system for dnvmg an agitator having an impeller and a propeller-like mixing blade.

Fig. 6 is a pictoπal 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 beanngs located in the top and bottom of the tank to permit rotation of the agitator m a second direction wherem the agitator includes an impeller having flow diversion vanes to cause bi-directional flow of the slurry mixture withm the mixing chamber and a second spaced propeller-like mixing blade located m the upper chamber to cause vigorous agitation of the slurry mixture in the vicinity of the mixing shaft;

Fig. 7 is a pictoπal 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 journelled in beanngs located in the top and bottom of the tank to permit rotauon of the agitator m a selected direction wherem the agitator includes an impeller having flow diversion vanes to cause bi-directional flow of the slurry mixture withm the mixing chamber and a pair of spaced separately dπven 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 bidirectional 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, bidirectional 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 MLXING 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 MLXT G 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 nght, side elevational view of the embodiment illustrated m 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 m the vicinity of the extractor;

Fig. 26(a) is a top pictonal 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 mto 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 pictonal 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 dnve 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 m the vicinity of the extractor for adjusting the concentration of the substantially homogeneous slurry before injection into a distπbution system;

Fig 29 is a pictoπal representation of yet another embodiment of an apparatus partially m 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 dπve shaft in the lower section of the mixing chamber and pair of spaced, fixed, separately dπven 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 with 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 distπbution system;

Fig 30 is a pictoπal representation of still yet another embodiment of an apparatus partially m 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 dπve 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 m the vicinity of the extractor for adjusting the concentration of the substantially homogeneous slurry mixture before an outlet for injection into a distπbution system;

Fig 31 is a pictoπal 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 dπve shaft m 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 pictonal representation of still yet another embodiment of an apparatus partially m 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 dπve shaft m 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 withm 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 in_jection mto a distribution system;

Fig. 33 is a pictonal 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 dπve 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 extenor of the mixing chamber for adding water m 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 pictoπal 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 distnbution system;

Fig. 35(a) is a pictonal 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 distπbution system;

Fig. 35(b) is a pictoπal representation of the extractor illustrated in Fig. 35(a) where the second conduit injects fluid into the first conduit with the extractor;

Fig 36 is a pictoπal 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 distπbution system; and

Fig. 37 is a pictoπal 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 adiusting the concentration of the substantially homogeneous slurry before an outlet for injection into a distπbution system.

DESCRIPTION OF THE PREFERRED EMBODIMENT

For purposes of background, a review of mixing systems for preparing and distnbuting a gypsum slurry mto an imgation system is provided hereinbelow

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

A typical mixing apparatus compπses a tank with an agitator, either a hoπzontally 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 imgation system for distπbution of the gypsum slurry therethrough for treatment of soil, plants, crops, trees, and the like. An electnc motor or a gasoline powered engine is used to dπve 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 mside 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 imgation system. The agitator continually processes the gypsum slurry by providing vigorous agitation dunng injection of the gypsum sluπy to the imgation 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 withm 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 with the tank.

Another known alternative structure of the mixing apparatus includes the use of a injectable extractor wherein water is added through the shroud mto the vicinity of the extractor to vary the concentration of the gypsum solution. In addition, the concentration of the gypsum solution can be vaπed 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 withm the tank The improved vertically mounted impeller can be used with any of the above-descπbed mixing apparatus, regardless of the structure thereof m terms of float valves, extractors, injectable extractors, floatable extractors or fixed extractors

The following descnptions 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 m 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 imgation system or distnbution 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 m 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 m Fig. 2 is illustrated in general detail m Fig 18.

As illustrated m Fig. 2, the axially extending shaft 56 is rotatably mounted in the bottom 66 of tank 44 in a beaπng support 70, which permits rotation of the shaft with the lower section 50. The top of the axially extending shaft 56 is mounted in a top beaπng member 76

wherem the top 80 of the axially extending shaft 56 extends through the beanng member 74 into operative engagement with a dnve pulley 86. The dnve pulley 86 is dπven by a dual, "V"- shaped dnve belts 90 An idler pulley 92 controls the tension within the dnve belts 90

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

As illustrated m Fig. 1, the dπve motor 110 is used to dπve a pump 114 and the dnve belts 102 to dnve 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 m 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 m 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 imgation 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 imgation system 162. In order to remove undesired mateπals 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 imgation system 162 m one of two modes, a full output mode and a metered output mode. At the full output mode, the gypsum slurry is injected directly mto the imgation system by the pump 114. In the metered output mode, the flow of the gypsum slurry is restncted by an adjustable oπfice 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 mjectable, 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 pnor 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 dπve the slurry 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 ma 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 imgation 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 propellerlike mixing blade 74 is operatively connected to the axially extending shaft 56 and is located, in the preferred embodiment, m the upper section 48 of the tank 44 When the axially extending shaft 56 is dπven m a counter-clockwise direction by dnve pulley 86, both the impeller 60 and the propeller-like mixing blade 74 are likewise dnven m 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 dπves 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 pictoπally represents a different structure of the vertically mounted agitator 54 from the structure depicted in Fig. 6. The agitator compnsmg the axially extending shaft 56, the dnven pulley 86 and the impeller 60 is substantially the same structure as illustrated m Fig 6.

In Fig 7, two separate spaced vertically mounted propeller-like mixing blade assemblies shown generally as 360 are mounted m the outerwall 340 of tank 44 Each vertically mounted propeller-like mixing blade assembly 360 includes a dnve pulley 362, a dπve shaft 370 and a propeller-like mixing blade 74 In the structure illustrated m Fig 7, the agitator 54 can be dnven m a counter-clockwise direction as shown by arrow 350. However, the propeller-like mixing blade assemblies 360 can be dnven m either the clockwise or counterclockwise direcuon. In the preferred embodiment, the propeller-like mixing blade assemblies 360 are dnven m 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 m a pictoπal 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 wherem the bi-directional flow diversion vanes 396 located m a plane substantially radial to the vertically extending dπve 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 sluπy 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 sluπy 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 descπbed 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 compnsmg 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 descnbed 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 descnbed hereinbefore, is used as shown m 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 dnven 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 descnbed above with respect to Fig. 28. However, a second conduit 498 is operatively connected to the first conduit 492 m 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 descnbed hereinabove, would function equally well with a floating extractor rather than a fixed extractor, as descnbed below

In Fig 30, the tank 44 utilizes an agitator 54, impeller 130 and propeller-like mixing blade 186, as descnbed in connection with Fig. 28 above. However, the extractor 174, as illustrated m 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 descnbed 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 sluπy within the extractor 174 pnor to the withdrawal of the same through the first conduit 492

Fig. 31 illustrates an apparatus which is similar in structure to that descnbed 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 descnbed 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 descnbed above for Fig. 29.

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

Fig. 33 illustrates that the dilution chamber 560 can be located extenor 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 vaπous 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 concuπently 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.

Claims

WHAT IS CLAIMED IS:

1. Apparatus for combining particulate matter and a fluid to form a slurry comprising a mixing chamber having an upper section and a lower section for combining particulate matter and a fluid to form a slurry; and an agitator having an axially extending shaft rotatably mounted in said tank and positioned to extend substantially vertically between said upper section and said lower section of the mixing chamber, said agitator including an impeller having flow diversion vanes which, upon rotation of said impeller in a selected direction, develop a bi-directional flow of particulate matter and fluid wherein one direction of low is directed along a path substantially parallel to the upper section of said mixing chamber and where in the other direction of flow is along a path generally perpendicular to said impeller and directed into both said upper section and said lower section to form a substantially homogenous slurry throughout the mixing chamber.

2. The apparatus of claim 1 wherein said impeller is operatively connected in a substantially perpendicular relationship to said axially extending shaft and positioned substantially in at least one of said lower section and said upper section of the mixing chamber and said agitator further includes a propeller-like mixing blade positioned substantially in the at least one of the upper section and lower section of the mixing chamber and spaced from the impeller to drive the slurry in a direction opposite the the direction of the generally perpendicular path of the slurry to cause a mixing action along a path substantially parallel to the axially extending elongated shaft.

3. The apparatus of claim 1 wherein said impeller is located substantially in said lower section of the mixing chamber.

4. The apparatus of claim 2 wherein said impeller is located substantially in the lower section of said mixing chamber and said propeller is located substantially in the upper section of said mixing chamber.

5. The apparatus of claim 1 wherein said impeller is in the form of an elongated member having a pair of ends, a first surface and an opposed, substantially parallel second surface, said first surface having a deflection vane positioned at each of said pair of ends and oriented relative to said elongated member whereupon rotation of said elongated member in a selected direction drives the deflection vanes into and deflects the slurry along a path substantially parallel to and outwardly from said elongated member.

6. The apparatus of claim 5 wherein the impeller further comprises at least one radial deflection vane positioned on said second surface at each of said pair of ends and oriented relative to said elongated member whereupon rotation of the elongated member in said selected direction drives the radial deflection vanes into and deflects the slurry along a path substantially radially and outwardly.

7. The apparatus of claim 5 wherein the impeller further comprise at least one axial deflection vane positioned on said second surface at each of said pair of ends oriented relative to said elongated member whereupon rotation of the elongated member in said selected direction drives the axial deflection vanes into and deflects the slurry along a path substantially perpendicular to and generally upwardly and outwardly from said elongated member.

8. The apparatus of claim 6 wherein the impeller further comprises a second radial deflection vane positioned on said second surface at each of said pair of ends adjacent to said at least one radial deflection vane and oriented relative to said elongated member whereupon rotation of the elongated member in said selected direction drives said second radial deflection vane into and deflects the slurry along a that substantially radially and outwardly from said elongated member in a direction opposite the slurry deflection path of said at least one radial deflection vanes.

9. The apparatus of claim 6 wherein the impeller further comprises at least one axial deflection vane positioned on said second surface at each of said pair of ends adjacent to said at least one radial deflection vane and oriented relative to said second elongated member whereupon rotation of the elongated member in said selected direction drive said at least one axial deflection vane into and deflects the slurry along a path substantially perpendicular to and generally upwardly and outwardly from said elongated member concurrently with the radial deflection vanes deflecting the slurry along a path substantially radially and outwardly from said elongated member.

10. Apparatus for mixing gypsum and water comprising a tank defining a mixing chamber having an upper section and an opposed lower section for mixing gypsum and water to form a gypsum slurry; and an agitator rotatably mounted in said tank and positioned to extend substantially vertically between said upper section and said lower section of the mixing chamber, said agitator including an impeller which is operatively connected in a substantially perpendicular relationship to agitator and positioned substantially in said lower section of the mixing chamber, said impeller having flow diversion vanes which, upon rotation of said impeller in a selected direction, develops a bi-directional flow of particulate matter and fluid wherein one direction of flow is directed in a path substantially parallel to said lower section of the mixing chamber and wherein the other direction of flow is along a path generally perpendicular to said substantially parallel path and directed generally upwardly from said lower section to said upper section to form a substantially homogenous slurry mixture throughout the mixing chamber.

11. The apparatus of claim 10 wherein said impeller is in the form of an elongated member having a pair of ends, a first surface and an opposed, substantially parallel second surface, said first surface having a deflection vane positioned at each of said pair of ends and oriented relative to said elongated member whereupon rotation of said elongated member in a selected direction drive the deflection vanes into and deflects the slurry along a path substantially parallel to and outwardly from said elongated member.

12. The apparatus of claim 11 wherein the impeller further includes on said opposed second surface at least one radial deflection vane at each of said pair of ends.

13. The apparatus of claim 11 wherein the impeller further comprises at least one axial deflection vane positioned on said second surface at each of said pair of ends oriented relative to said elongated member whereupon rotation of the elongated member in said selected direction drives the axial deflection vane into and deflects the slurry along a path substantially perpendicular to and generally upwardly and outwardly from said elongated member.

14. The apparatus of claim 12 wherein the impeller further comprises a second radial deflection vane positioned on said second surface at each of said pair of ends adjacent to said at least one radial deflection vane and oriented relative to said elongated member whereupon rotation of the elongated member in said selected direction drives said second radial deflection vane into and deflects the slurry along a path substantially radial and outwardly from said elongated member in a direction opposite the slurry deflection path of said at least one radial deflection vane.

15. The apparatus of claim 12 wherein the impeller further comprises at least one axial deflection vane positioned on said second surface at each of said pair of ends adjacent to said at least one radial deflection vane and oriented relative to said elongated member whereupon rotation of said elongated member in said selected direction drives said at least one axial deflection vane into and deflects the slurry along a path substantially perpendicular to and generally upwardly and outwardly from said elongated member concurrently with the radial deflection vanes deflecting the slurry along a path substantially radially and outwardly from said elongated member.

16. The apparatus of claim 12 wherein said impeller includes a second pair of radial deflecting vanes positioned on said second surface wherein one of each of said second pair of radial deflecting vanes is positioned adjacent to said radial deflection vanes and oriented relative to said elongated member whereupon rotation of said elongated member in a selected direction drives said second pair of radial deflecting vanes into and deflects the slurry along a path substantially radially and outwardly from the elongated member in a direction to cause a rapidly

rotating flow motion which is directed along a path which is substantially parallel to said axially extending shaft which drives the impeller.

17. The apparatus of claim 10 further comprising an extractor for withdrawing slurry from said mixing chamber.

18. The apparatus of claim 17 wherein said extractor is fixed within the mixing chamber.

19. The apparatus of claim 17 wherein said extractor floats within the mixing chamber.

20. The apparatus of claim 19 wherein said extractor includes a flotation member which floats said extractor in said slurry.

21. The apparatus of claim 19 wherein said extractor is operatively connected to a first conduit which communicates with an outlet to a distribution system, said extractor being adapted to pass withdrawn substantially homogeneous gypsum slurry to said first conduit for transportation to said outlet.

22. The apparatus of claim 21 wherein said extractor includes a member for adding a controlled volume of water into the substantially homogeneous gypsum slurry in the vicinity of an extraction zone within the extractor for controlling the concentration of gypsum per unit volume of gypsum slurry withdraw from the mixing chamber in the extraction zone of the extractor.

23. The apparatus of claim 22 wherein said extractor further includes a shroud which defines the extraction zone and substantially maintains the water added to the substantially homogeneous gypsum slurry in the extraction zone of the extractor.

24. The apparatus of claim 21 wherein a second conduit is operatively connected to the first conduit through a dilution chamber for adding a controlled volume of water to the substantially homogeneous gypsum slurry withdrawn by the first conduit for controlling the concentration of gypsum per unit volume of gypsum slurry.

25. The apparatus of claim 24 wherein said second conduit is operatively connected to said first conduit through a dilution chamber located in the vicinity of the extractor.

26. An apparatus of claim 24 when said second conduit is operatively connected to said first conduit through a dilution chamber located between a tank wall and said extractor.

27. The apparatus of claim 24 wherein said second conduit is operatively connected to first conduit through a dilution chamber located adjacent a tank wall and within the mixing chamber.

28. The apparatus of claim 24 wherein said second conduit is operationally connected to said first conduit through a dilution chamber located adjacent a tank wall and external to the mixing chamber.

29. The apparatus of claim 24 wherein said second conduit is operatively connected to said first conduit through a dilution chamber located within the extractor.

30. The apparatus of claim 10 wherein said agitator further includes a propeller-like mixing blade positioned substantially in said upper section of the mixing chamber and spaced from the impeller.

31. Apparatus for mixing solution grade gypsum and water comprising a tank defining a mixing chamber having an upper section and an opposed lower section for mixing solution grade gypsum and water to form a gypsum slurry; and an agitator having an elongated shaft member rotatably mounted in said tank and positioned to extend substantially vertically between said upper section and said lower section of the mixing chamber, said agitator including an impeller which is operatively connected in as substantially perpendicular relationship to said elongated shaft member and positioned substantially in said lower section of the mixing chamber, said impeller having an upper surface disposed towards said upper section of the mixing chamber and an opposed lower surface disposed towards said lower section of the mixing chamber, said agitator having on at least one of said upper surface and said lower surface flow diversion vanes which, upon rotation of said elongated 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 in a path substantially parallel to the upper section of said mixing chamber and wherein the other direction of flow is directed into a path generally perpendicular to said substantially parallel plane to form a substantially homogeneous slurry mixture throughout the mixing chamber.

32. The apparatus of claim 31 further comprising an extractor for withdrawing gypsum slu╧Çy mixture from said mixing chamber.

33. The apparatus of claim 31 wherein said agitator further includes a propeller-like mixing blade positioned in substantially the upper section of the mixing chamber and spaced from the impeller to cause mixing action to disrupt the slurry flow along a path substantially downward to the axially extending elongated shaft.

34. The apparatus of claim 32 wherein said extractor includes an outlet and a conduit for adding a controlled volume of water into the gypsum slurry for controlling the concentration of gypsum per unit volume of gypsum slurry withdraw from the mixing chamber through the outlet.

35. The apparatus of claim 34 wherein said extractor includes a shroud and wherein said conduit adds said controlled volume of water into the gypsum slurry within said shroud.

36. An agitator for mixing particulate matter in a fluid comprising an impeller having a central area, a first surface, an opposed second surface and a pair of ends, each of said pair of ends having formed on said first surface a first flow diversion vane and a second flow diversion vane, said first flow diversion vane having a leading edge and a trailing edge wherein the flow diversion vane forms an arcuate shaped surface extending in a direction towards said central area of the impeller and said second flow diversion vane is spaced a predetermined distance from said first flow diversion vane and 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 center area, said impeller when rotated in said selected direction in a fluid being capable of the developing a bi-directional flow motion having one flow in a path substantially parallel to the impeller and the other flow is in a path generally vertical to the central area of the impeller.

37. The agitator of claim 36 further comprising a third flow diversion vane located on said second surface and positioned above one of said first flow diversion vane and said second flow diversion vane, said third flow diversion vane having 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 of the impeller.

38. The agitator of claim 37 further comprising a forth flow diversion vane located on said second surface and positioned above the other of said first flow diversion vane and said second flow diversion vane, said fourth flow diversion vane having 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 of the impeller.

39. An agitator comprising an impeller having an elongated central member defining a central area, a first surface, an opposed second surface and a pair of ends, each of said pair of ends having a first flow diversion vane formed on said first surface having a leading edge and a trailing edge wherein the flow diversion vane forms an arcuate shaped surface extending in a direction towards said central area of the impeller; a second flow diversion vane formed on said first surface and spaced a predetermined distance from said first flow diversion blade and having a leading edge and a trailing edge wherein the flow diversion vane forms an arcuate shaped surface extending in a direction away from he center area, said leading edges of said first flow diversion vanes and said second flow diversion vanes being positioned in a selected direction.

40. The agitator of claim 39 further comprising a third flow diversion vane located on said second surface and adjacent one of said first flow diversion vanes and said second flow diversion vanes, said third flow diversion vane having 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 of the impeller.

41. The agitator of claim 40 further comprising

a fourth flow diversion vane located on said second surface and adjacent the other of said first flow diversion vanes and said second flow diversion vanes, said fourth flow diversion vane having 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 of the impeller.

42. The agitator of claim 39 wherein said agitator, when rotated in said selected direction in a mixture of particulate matter and fluid, is capable of the developing a bidirectional flow motion in a gypsum slurry mixture.

43. A method of preparing a substantially homogeneous slurry of particulate matter and fluid for distribution through an outlet comprising the steps of providing a tank having a mixing chamber including an upper section and a lower section; filling the mixing chamber with a desired amount of fluid; placing a desired amount of particulate matter in the mixing chamber; mixing the particulate matter and fluid by forming in said lower section of the mixing chamber with an impeller having bi-directional flow diversion vanes a bi-directional flow of particulate matter and fluid wherein one direction of directed flow of the particulate matter and fluid is in a path substantially parallel to the upper section of the mixing chamber and the other direction of directed flow is in a path generally perpendicular to said substantially parallel plane to form a substantially homogenous slurry mixture throughout the mixing chamber.

44. The method of claim 43 wherein said steps of mixing includes rotating in the lower section of the mixing chamber an impeller having flow diversion vanes for forming bidirectional slurry mixture flow.

45. The method of claim 44 wherein the step of mixing includes mounting the impeller for rotation about an axis passing substantially through the upper section and lower section of the mixing chamber.

46. The method of claim 43 wherein the step of mixing further includes rotating, in the vicinity of said upper section of the mixing chamber, a propeller-like blade mixer for forming a flow of slurry mixture in a direction which is substantially perpendicular to said substantially parallel plane to and spaced from the impeller to cause vigorous mixing action which disrupts the slurry mixture flow along a path substantially downward to the axially extending elongated shaft.

47. The method of claim 46 wherein the steps of mixing includes rotating the propellerlike blade mixer in a direction opposite to the direction of rotation of the impeller to interrupt the flow in the downward direction extending from the upper section of the mixing chamber to the lower section of the mixing chamber to cause vigorous mixing action.

48. The method of claim 46 wherein the step of mixing including rotating he impeller in a direction substsantially downward from the upper section of the mixing chamber to the lower section of the mixing chamber and rotating the propeller-like blade mixer in a direction of rotation to drive the slurry flow in a direction extending upwardly through the upper section of the mixing chamber to impact and disrupt the slurry flow developed by said impeller along a path substantially downward to the axially extending elongated shaft.

49. The method of claim 43 further comprising the steps of continuing the mixing step until a substantially homogeneous slurry mixture is obtained and during subsequent distribution.

50. A method of delivering a slurry mixture of predetermined density to an outlet for a distribution system comprising the steps of preparing a concentrated substantially homogenous slurry mixture of a predetermined substantially uniform density in a mixing chamber from a predetermined quantity of fluid and particulate material; withdrawing with an extractor from the mixing chamber the concentrated slu╧Çy mixture and transporting the withdrawn slurry mixture through a conduit to an outlet outside of the mixing chamber; and

adding within at least one of the extractor and said conduit with the mixing chamber a desired amount of fluid to the concentrated slurry mixture withdrawn from the mixing chamber to produce a diluted slurry mixture of predetermined density before said outlet.

51. The method of claim 50 wherein the step of adding includes adding the desired amount of fluid to the withdrawn slurry mixture at the extractor.

52. The method of claim 50 wherein the step of adding includes adding the desired amount of fluid to the withdrawn slurry mixture during transportation of the withdrawn slurry mixture in said conduit.

53. The method of claim 52 wherein the step of adding includes the use of a dilution chamber operatively connected to said conduit.