WO2005044436A1 - Procedes de melange ameliores et unites de melange associees - Google Patents

Procedes de melange ameliores et unites de melange associees Download PDF

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Publication number
WO2005044436A1
WO2005044436A1 PCT/NZ2004/000282 NZ2004000282W WO2005044436A1 WO 2005044436 A1 WO2005044436 A1 WO 2005044436A1 NZ 2004000282 W NZ2004000282 W NZ 2004000282W WO 2005044436 A1 WO2005044436 A1 WO 2005044436A1
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WO
WIPO (PCT)
Prior art keywords
tank
mixing
liquid
particulate material
mixing unit
Prior art date
Application number
PCT/NZ2004/000282
Other languages
English (en)
Inventor
Kevin Cosgrove
Original Assignee
Dan Cosgrove Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from NZ529386A external-priority patent/NZ529386A/xx
Application filed by Dan Cosgrove Ltd. filed Critical Dan Cosgrove Ltd.
Priority to AU2004287348A priority Critical patent/AU2004287348A1/en
Publication of WO2005044436A1 publication Critical patent/WO2005044436A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F21/00—Dissolving
    • B01F21/50—Elements used for separating or keeping undissolved material in the mixer
    • B01F21/504—Sieves, i.e. perforated plates or walls
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F21/00—Dissolving
    • B01F21/20—Dissolving using flow mixing
    • B01F21/22—Dissolving using flow mixing using additional holders in conduits, containers or pools for keeping the solid material in place, e.g. supports or receptacles
    • B01F21/221—Dissolving using flow mixing using additional holders in conduits, containers or pools for keeping the solid material in place, e.g. supports or receptacles comprising constructions for blocking or redispersing undissolved solids
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/50—Circulation mixers, e.g. wherein at least part of the mixture is discharged from and reintroduced into a receptacle
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F2215/00—Auxiliary or complementary information in relation with mixing
    • B01F2215/04—Technical information in relation with mixing
    • B01F2215/0413—Numerical information
    • B01F2215/0418—Geometrical information
    • B01F2215/0431—Numerical size values, e.g. diameter of a hole or conduit, area, volume, length, width, or ratios thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F2215/00—Auxiliary or complementary information in relation with mixing
    • B01F2215/04—Technical information in relation with mixing
    • B01F2215/0413—Numerical information
    • B01F2215/0436—Operational information
    • B01F2215/045—Numerical flow-rate values

Definitions

  • the present invention relates to methods and mixing units for mixing dry particulate materials with liquid. More specifically the invention relates to methods and associated mixing units for bulk, in-situ, on-demand mixing of materials such as fertilisers, including urea, for use in liquid applications such as field irrigation.
  • fertiliser is an important tool for maximising the value of land. For example, by supplementation of soils to encourage strong growth of grass that would not normally support growth levels achieved without using fertilisers.
  • urea urea
  • various nitrate compounds urea
  • complex fertiliser NPK
  • MAP mono-ammonium phosphate
  • DAP di-ammonium phosphate
  • Urea fertiliser is typically marketed as a solid in powder or granule form which is then applied either directly to the soil in solid form, or it is dissolved and/or diluted into water or other solutions and irrigated onto soil.
  • Recommendations to avoid this problem include applying solid forms of urea only when moisture is present on the area to be applied, or when there is a high likelihood of moisture occurring shortly after application, for example, from rain, dew or irrigation.
  • a further consideration when applying solid urea is that the uniformity of particle size is important. Where particles such as granules are not of a uniform size, variations in density of fertiliser applied to soil may result, as well as material handling issues from equipment not built to handle the unusual and/or variation in granule sizes.
  • liquid urea is manufactured by mixing solid urea with a sufficient quantity of water to make up the desired concentration of dissolved urea. The liquid is then applied using an irhgator or similar device, to the ground to be fertilised (termed 'fertigation' for the purposes of this specification).
  • irhgator or similar device to the ground to be fertilised (termed 'fertigation' for the purposes of this specification).
  • the method is labour intensive.
  • the expectation is that the end user, for example a farmer, will order the correct amount of urea (and typically store a considerable quantity of solid urea) and then, when it is required, measure out the desired quantity of solid urea and mix with water for application via an irrigation system.
  • a further problem is that fertilisers are difficult to mix evenly. Problems exist with a lack of uniformity during mixing and/or precipitate formation. Also urea also reacts endothermically during mixing with water which decreases the temperature to a point where precipitate formation is more likely. Also the dissolution rate slows or even stops in cooler temperatures caused by the endothermic reaction. Besides the problem of varying concentrations from non-uniform mixing and/or precipitate formation and/or un-dissolved solids, solids or precipitates can block irrigation equipment thus causing further undue labour and time being expended, and may also cause difficulties with achieving an even application of fertiliser.
  • fertilisers generally are that of safety. Many solid or dried fertilisers are dangerous to health, for example, if fertiliser dust is inhaled and/or the fertiliser is handled using bare skin, the user may suffer an adverse toxic or allergic reaction. In addition, bulk amounts of fertiliser are difficult to handle due to physical size as lifting machinery and other equipment such as pumps and storage hoppers are required.
  • One ideal method of delivering a fertiliser would be an automated or semi- automated mixing unit and associated method that is available on demand, is cost effective, safe, applies an accurate amount of fertiliser to the area to be fertilised, and is able to be installed in-situ at or close to the distribution site.
  • the term 'dry particulate material' will be used interchangeably with the term 'fertiliser'. This should not be seen as limiting as it should be appreciated by those skilled in the art that the method can also be applied for mixing dry particulate materials other than just fertilisers.
  • the term 'bulk mixing' refers to amounts of greater than approximately 50 litres of aqueous solution but this should not be seen as limiting i.e. it is possible to use lesser amounts without departing from the scope of the invention as described.
  • a method of bulk mixing a dry particulate material and a liquid to form an aqueous solution including the steps of:
  • the method is achieved by adding a total of approximately 15 to 50 separate doses of dry particulate material to the liquid to form the resulting aqueous solution.
  • each dose may be approximately 10 kg of dry particulate material per 750 litres of liquid. It should be appreciated by those skilled in the art, however, that a dose above or below this range may also be used where greater or lesser concentrations of aqueous solution are desired.
  • a method of bulk mixing a dry particulate material and a liquid to form an aqueous solution including the step of:
  • approximately 250 kg of dry particulate material is added to 750 litres of liquid. It should be appreciated that amounts outside of 250kg dry particulate material to 750 litres of liquid may also be used in accordance with the present invention and that this amount is given by way of illustration only.
  • the metered dose of dry particulate material and liquid is passed through an inlet filter before entry into the mixing tank.
  • the inlet filter may be a metal mesh of substantially 20mm x 3mm holes. It is the applicant's experience that granules of dry particulate material strike the surface of the mesh and, if small enough, pass through the mesh or, if larger, are caught by the mesh and breakdown (to eventually pass through the mesh) due to the action of the liquid passing over the mesh and granules.
  • the filter is of a cylindrical shape with the liquid entering one end of the cylinder as a spray. Solid dry particulate material also enters the same end of the cylinder as the liquid.
  • the mesh is located at a point substantially central to the cylinder cross-section.
  • the method includes a further step, step (d), after step (b) or step (c) of: (d) recycling the aqueous solution in the mixing tank through the inlet filter.
  • the aqueous solution is recycled in step (d) by drawing aqueous solution from the mixing tank via a recycle pump preferably located at the bottom of the mixing tank.
  • the mixing tank may be capable of retaining substantially from 500 to 3000 litres of liquid or an aqueous solution. It should be appreciated by those skilled in the art, however, that the size of the mixing tank may be dependent on the amount of dry particulate material to be mixed, hence, if a greater amount of aqueous solution is required, larger mixing tanks may be used and similarly, for smaller amounts, smaller mixing tanks may be used.
  • the mixing tank may be at least partially filled with liquid before dry particulate material is added.
  • the liquid added to the tank initially may be the total amount of liquid to be mixed.
  • the liquid or aqueous solution in the mixing tank may be recycled back through the inlet filter.
  • liquid may be recycled by drawing liquid from the base of the mixing tank via a pump.
  • it may be advantageous to include an outlet filter located between the tank outlet and the inlet filter, more preferably between the tank outlet and recycle pump. Most preferably this outlet filter may be made up of a smaller sized mesh than the inlet filter to remove any un-dissolved particulate material.
  • a method of bulk mixing a dry particulate material and a liquid to form an aqueous solution including the steps of: (a) adding a dose of dry particulate material to a liquid in a mixing unit that includes:
  • an interior tank that: a. is situated at least partially within the exterior tank; b. drains liquid into an exterior tank via one or more narrow apertures; and, c. a recycle loop including a pump for conveying liquid from the base of the exterior tank into the top of the interior tank configured such that the flow rate of liquid through the recycle loop is sufficient to create a turbulent environment in the interior tank;
  • the mixing unit is also configured to, in- operation when the recycle pump is running, result in a liquid level differential between the liquid level in the interior tank and the liquid level in the exterior tank.
  • this differential is approximately 50 to 300 mm, more preferably, approximately 200 mm.
  • the flow rate of liquid through the recycle loop is operated at approximately 200 to 300 litres per minute, more preferably, approximately 260 litres per minute. This flow rate amount should not be seen as limiting as it should be appreciated by those skilled in the art that this amount may vary depending on variables such as the stage of operation, the particulate material being mixed and aspects of the mixing unit design.
  • the exterior tank holds approximately 500 to 6000 litres of liquid, preferably approximately 4000 litres and the interior tank holds approximately 100 to 1500 litres of liquid, preferably approximately 1150 litres.
  • the interior tank is configured to include a total of six outlet apertures which are preferably hoses.
  • five of the outlet apertures are positioned equidistantly around the circumference of the bottom of the interior tank.
  • the outlet hoses are positioned such that their outlet is pointed in an upwards direction.
  • there is one centrally located outlet hose which is attached to the bottom of the interior tank.
  • the outlet of this hose is located towards or on the floor of the exterior tank.
  • the interior tank of the above mixing unit further includes a number of wall sections within the interior tank.
  • the interior tank includes a plurality of wall sections (preferably a total of 10 sections) of equal width and height with every second section including slots in a mesh configuration through which liquid can pass. It should be appreciated by those skilled in the art that a variety of differing interior wall section configurations may be used without departing from the scope of the invention as described.
  • the outlet apertures located around the circumference of the base of the interior tank are located to substantially correspond to each mesh wall section described above.
  • the interior tank also has a mesh base section located above the actual floor of the interior tank.
  • the mesh in both the wall sections and base section are of a size sufficient to filter any large particles of solid fertiliser and, through the eroding action of liquid within the interior tank, be retained until reduced in size to a point when the particle can pass through the mesh.
  • the preferred mesh has a plurality of apertures of approximately 20mm x 3mm in size.
  • the time for the mixing operation is approximately 60 minutes. It should be appreciated that the time period may vary depending on the characteristics of the material being mixed and other variables such as the ambient temperature. However, it is the inventor's experience that a time period of 60 minutes is sufficient for most fertiliser applications such as for urea mixing.
  • the recycle line when mixing is complete, may be detached from the interior tank inlet and the recycle pump used to pump the liquid fertiliser solution to a holding tank or directly into an irrigation system.
  • the exterior tank includes a level control mechanism to shut off the liquid supply when a predetermined level of liquid in the mixing unit is reached.
  • the level control mechanism is a ballcock valve located at the liquid inlet.
  • the dry particulate material is added to the mixing unit via apparatus including an auger, a hopper, a funnel and combinations of these apparatus.
  • the applicant has found that by carefully controlling the amount of dry particulate material added in small doses, or adding the material at or below the specified flow rate or by specific mixing unit design, the above methods and mixing units result in an unexpected improvement. Improvements such as disadvantages of the prior art including incomplete bulk mixing and high costs from equipment requirements, transport and other costs have been overcome.
  • the machinery is simple in design and simple to operate, thus lowering capital costs and importantly, there is substantially no particulate formation that would lead to incomplete mixing.
  • the methods and associated mixing units also enable the process of 'fertigation' or applying fertiliser directly to pasture via an irrigation system as the aqueous solution formed can be pumped directly into an irrigation system.
  • the dry particulate material may be a fertiliser.
  • the fertiliser may be selected from the group consisting of: urea, ammonium nitrate, calcium nitrate, sodium nitrate, complex fertiliser (NPK), mono ammonium phosphate (MAP), di-ammonium phosphate (DAP), potassium phosphate, and combinations thereof.
  • the dry particulate material may be urea.
  • the dry particulate material is in the form of a plurality of granules. It is envisaged that granules need not be of uniform size or shape.
  • An advantage of the present invention is that a range of dry particulate sizes may be used and where granules are large, they are reduced into smaller sizes via the mixing method and steps of the present invention.
  • the liquid may be water. It should be appreciated by those skilled in the art that other liquids and/or solids suspended in the liquid may also be included, for example weed killers, pesticides and other compounds.
  • no further liquid may be added to the mixing tank once addition of dry particulate material begins.
  • the aqueous solution obtained from the method substantially as described above may be transferred to either a storage tank or directly to an irrigation system. It is the applicant's experience that by use of a storage tank, a semi-continuous process is obtained whereby, as irrigation proceeds, the soil may be irrigated with the aqueous solution pumped from the storage tank, and the storage tank topped up as required from the mixing tank.
  • the dosing process including the metering of dry particulate material, may be completed using an automated process and control system.
  • the operator may insert into the control system either: the amount of dry particulate material to be mixed; the end concentration of aqueous solution required; or the end volume of aqueous solution required; and combinations thereof.
  • the dry particulate material is stored before use in a storage hopper.
  • the hopper is substantially water and air tight.
  • the hopper includes weight measurement apparatus such as one or more load cells which measure the weight of dry particulate material held within the hopper.
  • the weight measurement apparatus are preferably linked to an overall control system which monitors the weight of material added from the hopper into the mixing unit and starts and stops addition of material based on the weight parameters entered by the operator or according to a predetermined weight parameter or parameters.
  • the hopper is elevated above the ground. It is the inventor's experience that, by raising the hopper, the overall unit can be used for other applications such as for general storage of dry particulate material and material stored within the hopper can be easily emptied by gravity, for example into a truck. This is advantageous as it is preferable to have only one storage hopper per site to avoid unnecessary capital expense.
  • a further advantage of easy emptying is that the dry particulate material used can be altered relatively easy without need for pumps or other solids transport devices.
  • An advantage of the above mixing methods are that the dose of aqueous solution added to a particular area for example a field, may be controlled and manipulated thus allowing the operator greater control of the dry particulate material/aqueous solution.
  • an aqueous solution produced in accordance with the method substantially as described above.
  • a mixing unit including: a feed mechanism for adding dry particulate material to a mixing tank; a mixing tank; a recycle loop for conveying liquid from the base of the mixing tank to the top of the mixing tank; characterised in that the feed mechanism is capable of adding a plurality of doses of dry particulate material to liquid in the mixing tank, whereby each dose is added at a ratio of approximately 1 :40 to 1 :500 weight dry particulate material to volume liquid (w/v).
  • a mixing unit including: a feed mechanism for adding dry particulate material to a mixing tank; a mixing tank; a recycle loop for conveying liquid from the base of the mixing tank to the top of the mixing tank; characterised in that the feed mechanism is capable of adding a measured flow rate of dry particulate material to liquid in the mixing tank, whereby the flow rate does not exceed approximately 9 kg/min.
  • the mixing unit may include an inlet filter through which the dry particulate material passes before entry into the mixing tank.
  • the liquid used may also pass through the same inlet filter as the dry particulate material.
  • the dry particulate material and liquid may be in intimate contact within the inlet filter.
  • the mixing unit may include an outlet filter located within the recycle loop through which the liquid and/or aqueous solution passes.
  • a mixing unit including: an exterior tank; an interior tank that:
  • the mixing unit is also configured to, in-operation when the recycle pump is running, result in a liquid level differential between the liquid level in the interior tank and the liquid level in the exterior tank.
  • this differential is approximately 50 to 300 mm, most preferably 200 mm.
  • this amount may vary depending on the flow rate through the recycle loop and the scale and dimensions of the unit items such the as size of the interior tank outlets and the interior and exterior tank circumference.
  • the flow rate of liquid through the recycle loop is approximately 200 to 300 litres per minute, more preferably approximately 260 litres per minute.
  • this flow rate should not be seen as limiting as it should be appreciated by those skilled in the art that this amount may vary depending on the scale and dimensions of the unit items such the as size of the interior tank outlets, the interior and exterior tank circumference and the recycle pump rating.
  • the exterior tank holds approximately 500 to 6000 litres of liquid, preferably approximately 4000 litres and the interior tank holds approximately 100 to 1500 litres of liquid, preferably approximately 1150 litres.
  • the interior tank is preferably elevated from the floor of the exterior tank by legs. In preferred embodiments, a total of five legs are used, with the legs being positioned equidistant from each other.
  • the legs elevate the interior tank approximately 500 to 900 mm above the floor of the exterior tank. More preferably, the interior tank is elevated approximately 700 mm above the floor of the exterior tank.
  • the interior tank has an inlet at the top of the tank for introducing a particulate material such as fertiliser into the interior tank.
  • the interior tank is configured to include a total of six outlet apertures which are preferably hoses.
  • five of the outlet apertures are positioned equidistantly around the circumference of the bottom of the interior tank.
  • the outlet hoses are positioned such that their outlet is pointed in an upwards direction.
  • there is one centrally located outlet hose which exits the bottom of the interior tank.
  • the outlet of this hose is positioned on the floor of the exterior tank.
  • the interior tank of the above mixing unit further includes a number of wall sections within the interior tank.
  • the interior tank includes a total of 10 sections of equal width and height with every second section including slots in a mesh configuration through which liquid can pass. It should be appreciated by those skilled in the art that a variety of differing interior wall section configurations may be used without departing from the scope of the invention as described.
  • the outlet apertures located around the circumference of the base of the interior tank are located to substantially correspond to each mesh wall section described above.
  • the interior tank also has a mesh base section located above the actual floor of the interior tank.
  • the mesh in both the wall sections and base section are of a size sufficient to filter any large particles of solid fertiliser and, through the eroding action of liquid within the interior tank, be retained until reduced in size to a point when the particle can pass through the mesh.
  • the preferred mesh has a plurality of apertures of approximately 20mm x 3mm in size.
  • the recycle line when mixing is complete, may be detached from the interior tank inlet and the recycle pump used to pump the liquid fertiliser solution to a holding tank or directly into an irrigation system.
  • the exterior tank includes a level control mechanism to shut off the liquid supply when a predetermined level of liquid in the mixing unit is reached.
  • the level control mechanism is a ballcock valve located at the liquid inlet.
  • the mixing unit feed mechanism may be an auger.
  • the mixing unit may further include a storage hopper for storage of dry particulate material prior to entry into the feed mechanism.
  • the storage hopper may include at least one weight measurement device such, as a load cell.
  • the weight measurement device or devices may be used to monitor the dose of dry particulate material added to the mixing unit and/or may be used to monitor the flow rate of dry particulate material added to the mixing unit.
  • the amount of dose added and/or flow rate of dry particulate material added to the mixing unit may be controlled via an automated control system.
  • the mixing unit may include a storage tank for housing of aqueous solution after mixing in the mixing tank.
  • the unit may be adapted to be able to deliver aqueous mixed solution directly into an irrigation system (termed 'fertigation' for the purposes of this specification).
  • Figure 1 is a flow diagram of a preferred embodiment of the present invention
  • Figure 2 is a cross-section elevation view of one preferred mixing unit embodiment
  • Figure 3 is a partial cross-section plan view of the embodiment shown in Figure 2.
  • dry particulate material such as urea (1 ) arrives at the processing site via standard transport methods, in this example depicted as a truck (2).
  • the site is a mixing unit located on a farm (generally indicated by arrow 18).
  • the dry particulate material being either a fertiliser, urea fertiliser or material. This should not be seen as limiting as it should be appreciated by those skilled in the art that other materials besides fertiliser may be used in accordance with the present invention.
  • the fertiliser (1 ) is transported using known means such as a pump (3) into a storage hopper (4) on the mixing unit (18).
  • the hopper (4) is substantially watertight and air-tight and preferably capable of retaining a store of fertiliser (1) for use at a later time.
  • the hopper (4) is elevated above ground level sufficient to allow access underneath by a truck (2). This has the advantage of allowing easy access to transport vehicles (2) in the case where the hopper (4) is to be emptied and, as the hopper (4) is elevated, the material (1 ) within the hopper (4) can empty via gravity without need for various solids transport devices such as pumps.
  • the hopper (4) also preferably includes at least one weight sensing device, such as a load cell (not shown).
  • This device aids in determining the dose of fertiliser (1 ) to be mixed into liquid (7) for example, an operator can visually monitor the weight of fertiliser (1 ) added from the hopper (4) by viewing the weight change as measured via the load cell or cells.
  • the weight measurement devices are monitored by a control system which measures the weight of material (1 ) in the hopper (4) and, based on predetermined parameters starts, stops and/or controls the flow rate of fertiliser (1 ) added to the liquid (7) in the mixing tank (11).
  • the operator When the fertiliser material (1 ) is required, the operator e.g. a farmer, enters a parameter into a control system (not shown) including: the desired quantity of dried particulate fertiliser (1) to be used; the volume of aqueous solution required; or the concentration of aqueous solution required.
  • the control system then begins the mixing process by adding liquid (7) to a mixing tank (11 ) up to the desired quantity.
  • the desired quantity of liquid (7) is based on at least one of the parameters chosen above.
  • the liquid (7) is added using control and actuator devices, for example, a valve (8). It is desirable for the valve (8) opening (not shown) to be substantially water-tight and air-tight.
  • a further advantage of the water-tight and air-tight valve (8) is that it is simple to clean the auger (5) and measuring container (6) as the valve (8) prevents blockages due to lump formation with moisture in the auger (5).
  • liquid flow (7) to the tank (11 ) is stopped and a recycle pump (14) is started.
  • Liquid (7) then flows in a closed loop through an inlet filter (10), into the mixing tank (11 ), out of a tank outlet (12), through an outlet filter (13), through the recycle pump (14), and back through the inlet filter (10).
  • a first metered dose of fertiliser (1) is transported to a measuring container (6) via a screw auger (5) or other solids transport device.
  • the fertiliser (1) is preferably retained within the measuring container (6) until the first desired discrete dosage is reached (measured for example using a level controller on the container via load cells under the hopper (4) or a flow rate monitor on the auger (5)).
  • a valve (9) opens at the bottom of the container (6) and the fertiliser (1), via gravity, passes through to the inlet filter (10) where it mixes with the liquid (7) in the mixing tank (11 ). It should be appreciated that other transport mechanisms besides gravity may be used in accordance with the present invention.
  • a metered volume of approximately 250 kg of fertiliser (1 ) is transported via a screw auger (5) or other solids transport device on a continuous basis to the mixing tank (11 ) containing approximately 750 litres of liquid (7) via the inlet filter (10).
  • the flow rate of fertiliser (1) is carefully monitored so that it does not exceed approximately 9 kg/min.
  • the fertiliser (1 ) either passes directly through the inlet filter (10) or, if the particles are too large, the fertiliser (1 ) is retained by an inlet filter mesh (not shown) within the inlet filter (10). Through the dissolving action of liquid (7) passing over the retained fertiliser (1 ), the larger particles are broken down until they are small enough to pass through the inlet filter mesh.
  • the liquid (7) and fertiliser (1) mix to form an aqueous solution via the turbulent action of the solution in the tank (11 ).
  • the turbulent action results from the liquid (7) entering the tank (11 ) and/or exiting the tank (11 ). It is the applicant's experience that it is preferable to avoid the use of impellers or other mixing elements in the mixing tank (11 ) to avoid extra capital cost, although it should be appreciated by those skilled in the art that such mixing elements could be included, if so desired.
  • further fertiliser (1 ) may be added to the mixing tank (11 ) in further amounts or does using either the 'mini-batch' or 'semi- continuous' methods until the desired volume or concentration of fertiliser (1) enters the mixing tank (11) and/or holding tank (16) and/or irrigation system (17).
  • the aqueous solution formed in the mixing tank (11 ) may then either be pumped (15) to a larger holding tank (16) for later application via an irrigation system (17), or pumped (15) directly into an irrigation system (17) for application to soil, termed 'fertigation' for the purposes of this specification.
  • semi- continuous irrigation (17) is possible i.e. holding tank (16) levels may be monitored and as they reduce, more aqueous solution may be produced, topping up the holding tank (16) level.
  • FIG. 2 shows a front elevation of the manual batch mixing unit along section B shown in Figure 3.
  • Figure 3 shows a partial plan elevation along section A shown in Figure 2.
  • the manual batch mixing unit 50,100 includes two tanks 51 ,52, one positioned within the other tank (the interior tank 51 ) and an outer larger tank (the exterior tank 52).
  • the exterior tank 52 is approximately 6000 litres in size and in operation, holds approximately 4000 litres of liquid.
  • the interior tank 51 has a capacity of approximately 1150 litres.
  • the interior tank 51 is elevated from the floor of the exterior tank 52 by legs 53.
  • legs 53 In preferred embodiments, a total of five legs 53 are used.
  • the legs 53 are positioned equidistant from each other and are located to correspond to each mesh wall section 57A.
  • the interior tank 51 has an inlet 54 at the top of the tank which is accessible from the exterior of the unit. Fertiliser 1 is inserted via a hopper 4 and transport device 5, in this case an auger 5, into the interior tank inlet 54.
  • the interior tank 51 is configured to include a total of six outlet hoses 55,56. There are five outlet hoses 55 positioned equidistantly around the circumference of the bottom of the interior tank 51. These outlet hoses 55 are positioned such that their outlet is pointed in an upwards direction. One centrally located outlet hose 56 exits the approximate centre of the bottom of the interior tank 51 and the outlet of this hose 56 is positioned on the floor of the exterior tank 56.
  • the interior tank 51 also includes a number of wall sections 57A, 57B within the interior tank 51.
  • a total of 10 sections of equal width and height 57A.57B are used.
  • Every second section labelled 57A includes slots in a mesh configuration (not shown) through which liquid can pass.
  • the remaining wall sections 57B are solid and do not include any mesh portions. It should be appreciated that a variety of differing wall section 57A.57B configurations may be used without departing from the scope of the invention as described.
  • the interior tank 51 also has a mesh base section 58 located above the actual floor of the interior tank 51.
  • the mesh in both the wall sections 57A and base section 58 is of a size sufficient to filter any large particles of solid fertiliser 1 and, through the eroding action of liquid within the interior tank 51 , be retained until reduced in size to a point when the particle can pass through the mesh.
  • the liquid that passes through the mesh wall sections 57A empties from the interior tank 51 via the outlet hoses 55 located around the circumference of the bottom of the interior tank 51.
  • the liquid that passes through the mesh base section 58 flows from the interior tank 51 via the centrally located outlet hose 56.
  • a recycle loop 59,60,61 ,62 is included as part of the unit.
  • the loop includes a recycle line 59. Liquid from outlet 60 located at the bottom of the exterior tank 52 passes into a recycle pump 61 and, via the recycle line 59, into the interior tank 51 via the interior tank inlet 62.
  • the recycle line 59 may be detached from the interior tank inlet 62 and the recycle pump 61 used to pump the liquid fertiliser solution to a holding tank (not shown) or directly into an irrigation system (not shown).
  • the exterior tank 52 also includes a liquid inlet 63, a ballcock valve 64 to turn the liquid flow off and an access way 67 for maintenance.
  • the user fills the exterior and interior tanks 51 ,52 by adding liquid via the liquid inlet 63.
  • the liquid for most applications is envisaged as being water however this should not be seen as limiting as other liquids may also be used without departing from the scope of the invention.
  • the tanks 51 ,52 are full at the appropriate level 65 once the ballcock valve 64 shuts off the liquid flow through the liquid inlet 63.
  • the mixing unit 50, 100 is designed such that, through backflow through the outlet hoses 55,56, the interior tank 51 also fills to the same level as the exterior tank 52.
  • a desirable flow rate is approximately 260 litres per minute of liquid. This flow rate enables a sufficient level of turbulence in the unit 50,100 to ensure complete uniform mixing of fertiliser 1 into solution. It should be appreciated that this rate is provided as an indication only and that other flow rates may also be appropriate such as: for different particulate materials 1 ; different scales of operation; and variations in tank 51 ,52 dimensions and configuration.
  • a further critical parameter found by the inventor is that the interior tank 51 outlet hoses 55,56 must sufficiently inhibit flow from the interior tank 51 such that an in- operation level differential results between the liquid level in the interior tank 66 and the exterior tank 65. It is the inventor's experience that this differential is approximately 100 mm to 200 mm however this should not be seen as limiting as it should be appreciated that this differential level may vary depending on variables such as: the particulate materials 1 used; different scales of operation; and variations in tank 51 ,52 dimensions and configuration.
  • fertiliser 1 is added via a hopper 4 and transport device 5, in this case an auger 5, into the interior tank inlet 54.
  • a single dose of fertiliser 1 is preferably added and the inlet 54 closed.
  • the amount of fertiliser 1 added is determined by the user based on the end concentration of fertiliser 1 in the liquid solution required.
  • the mixing unit 50,100 is then left to operate.
  • a total of 1 hour of mixing is required to ensure that a uniform concentration of liquid solution is reached.
  • the recycle pump 61 is stopped and the recycle line 59 is detached from the recycle inlet 62 on the interior tank 51.
  • the recycle line 59 may then be attached to a storage tank (not shown) or directly to an irrigation system (not shown) and the mixing unit 50,100 emptied of liquid solution by operating the recycle pump 61. Summary
  • dry particulate materials may also be added besides fertiliser and further, that more than one type of material may be mixed.
  • more than one liquid may be used, for example the addition of oil and water.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)

Abstract

L'invention concerne un appareil et un procédé permettant de mélanger de manière homogène des fertilisants particulaires secs avec un liquide, au moyen d'unités de mélange (50), dans des procédés de mélange commandés en discontinu ou en continu, la quantité de matériau particulaire sec étant ajoutée soit: (a) en petite doses, conservant des rapports compris entre 1: 40 et 1: 500 en poids de matériau particulaire sec au liquide en volume (w/v), soit (b) le matériau particulaire est ajouté au liquide à un débit massique égal ou inférieur à 9 Kg/min.
PCT/NZ2004/000282 2003-11-07 2004-11-05 Procedes de melange ameliores et unites de melange associees WO2005044436A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2004287348A AU2004287348A1 (en) 2003-11-07 2004-11-05 Improved mixing methods and associated mixing units

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NZ529386A NZ529386A (en) 2003-11-07 2003-11-07 Fertilizer and water mixing method for irrigation to soil
NZ529386 2003-11-07

Publications (1)

Publication Number Publication Date
WO2005044436A1 true WO2005044436A1 (fr) 2005-05-19

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PCT/NZ2004/000282 WO2005044436A1 (fr) 2003-11-07 2004-11-05 Procedes de melange ameliores et unites de melange associees

Country Status (2)

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AU (1) AU2004287348A1 (fr)
WO (1) WO2005044436A1 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104147975A (zh) * 2014-08-07 2014-11-19 国家电网公司 一种可直接投加sncr脱硝剂的自动设备及其配制方法
AU2009276016B2 (en) * 2008-07-31 2015-04-09 Casale Sa Process and plant for the production of a urea solution for use in SCR process for reduction of NOx
AU2013213700B2 (en) * 2012-08-31 2017-08-17 China Petroleum & Chemical Corporation Apparatus for producing aqueous urea solution used in vehicles and method of using the same
CN107774183A (zh) * 2016-08-31 2018-03-09 衡水卡力洁环保科技有限公司 一种车用尿素生产设备及工艺
WO2019160923A1 (fr) * 2018-02-13 2019-08-22 Ecolab Usa Inc. Système et procédé de dissolution de produits chimiques solides et de génération de solutions liquides
CN114177829A (zh) * 2021-12-02 2022-03-15 井冈山北新建材有限公司 一种减水剂自动定量添加装置及控制方法

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US4026673A (en) * 1975-05-29 1977-05-31 Leonard Russo Apparatus for dissolving and dispensing fertilizer to either of two water streams of different pressure
US4077612A (en) * 1973-12-04 1978-03-07 Ricciardi Ronald J Metering and wetting system
US4863277A (en) * 1988-12-22 1989-09-05 Vigoro Industries, Inc. Automated batch blending system for liquid fertilizer
EP0460804A1 (fr) * 1990-06-06 1991-12-11 United Kingdom Atomic Energy Authority Procédé pour mélanger un liquide et des solides, et appareil
WO1998055213A1 (fr) * 1997-06-03 1998-12-10 Grande Paroisse S.A. Dispositif pour melanger et dissoudre dans un liquide des granules solides, en particulier pour la production d'engrais phospho-azotes
WO2001085351A1 (fr) * 2000-05-05 2001-11-15 Rakesh Kumar Aggarwal Melangeur et procede permettant de melanger des liquides ou un solide et un liquide

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US4077612A (en) * 1973-12-04 1978-03-07 Ricciardi Ronald J Metering and wetting system
US4026673A (en) * 1975-05-29 1977-05-31 Leonard Russo Apparatus for dissolving and dispensing fertilizer to either of two water streams of different pressure
US4863277A (en) * 1988-12-22 1989-09-05 Vigoro Industries, Inc. Automated batch blending system for liquid fertilizer
EP0460804A1 (fr) * 1990-06-06 1991-12-11 United Kingdom Atomic Energy Authority Procédé pour mélanger un liquide et des solides, et appareil
WO1998055213A1 (fr) * 1997-06-03 1998-12-10 Grande Paroisse S.A. Dispositif pour melanger et dissoudre dans un liquide des granules solides, en particulier pour la production d'engrais phospho-azotes
WO2001085351A1 (fr) * 2000-05-05 2001-11-15 Rakesh Kumar Aggarwal Melangeur et procede permettant de melanger des liquides ou un solide et un liquide

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU2009276016B2 (en) * 2008-07-31 2015-04-09 Casale Sa Process and plant for the production of a urea solution for use in SCR process for reduction of NOx
AU2013213700B2 (en) * 2012-08-31 2017-08-17 China Petroleum & Chemical Corporation Apparatus for producing aqueous urea solution used in vehicles and method of using the same
CN104147975A (zh) * 2014-08-07 2014-11-19 国家电网公司 一种可直接投加sncr脱硝剂的自动设备及其配制方法
CN107774183A (zh) * 2016-08-31 2018-03-09 衡水卡力洁环保科技有限公司 一种车用尿素生产设备及工艺
WO2019160923A1 (fr) * 2018-02-13 2019-08-22 Ecolab Usa Inc. Système et procédé de dissolution de produits chimiques solides et de génération de solutions liquides
US10870091B2 (en) 2018-02-13 2020-12-22 Ecolab Usa Inc. System for dissolving solid chemicals and generating liquid solutions
CN114177829A (zh) * 2021-12-02 2022-03-15 井冈山北新建材有限公司 一种减水剂自动定量添加装置及控制方法
CN114177829B (zh) * 2021-12-02 2023-07-18 井冈山北新建材有限公司 一种减水剂自动定量添加装置及控制方法

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