WO2016191801A1

WO2016191801A1 - Mixing apparatus

Info

Publication number: WO2016191801A1
Application number: PCT/AU2016/050412
Authority: WO
Inventors: David Charles COLLINS
Original assignee: CEM INTERNATIONAL Pty Ltd
Current assignee: CEM INTERNATIONAL Pty Ltd
Priority date: 2015-06-03
Filing date: 2016-05-26
Publication date: 2016-12-08
Anticipated expiration: 2017-12-03
Also published as: AU2016272713A1

Abstract

Mixing apparatus including a mixing vessel (11) having a horizontally disposed hollow cylindrical body (12) with opposed torispherical ends (13,14) forming a substantially enclosed internal mixing zone (17), said torispherical ends and said hollow cylindrical body each having an inwardly facing surface that merge smoothly into one another, a rotatable shaft (18) rotatable about a horizontal rotation axis, said rotatable shaft having a plurality of mixing paddle members (19) extending laterally from said rotatable shaft having free end zones spaced inwardly from the inwardly facing surface of said mixing vessel, drive means (26) for driving said rotatable shaft, first connection means (28) for connecting said internal mixing zone to a vacuum or pressure source to create a condition conducive to moving one or more materials to be mixed to said internal mixing zone, second connection means (29,30) for introducing at least one material to be treated into said internal mixing zone, in use, via vacuum or pressure means, and discharge means leading from a lower most zone of said internal mixing zone, said discharge means including a discharge closure member (36) positionable at or adjacent said inwardly facing surface of internal mixing zone when located in a closed position.

Description

MIXING APPARATUS

FIELD OF THE INVENTION

[0001 ] The present invention relates to improvements in mixing apparatus particularly for mixing quantities of dry particulate material to create a

homogenous blend. The invention has particular application in the field of mixing dairy particulate materials for producing infant formula but is not necessarily limited to this application. The apparatus may also be used to mix liquids or semi liquid materials.

BACKGROUND OF THE INVENTION

[0002] Commercial blenders and mixing apparatus have a variety of constructions. The present invention relates to mechanical type mixers where some form of mechanical beater or the like is repeatedly passed through the materials to effect the desired mixing of the materials. These mixers include paddle type mixers where the apparatus includes a vessel with mixing paddles mounted on one or perhaps two shafts that are rotated to move the mixing paddles through the space within the vessel. The vessel normally has an open space above the mixing zone with one or more introduction points for introducing of the materials to be mixed. A lower discharge opening is typically provided leading from a lower most point or zone of the vessel. Such mixing vessels are typically gravity loaded from one or more elevated material storage hoppers through metering equipment to enable the desired blend or mixture to be established within the mixing vessel.

[0003] One such mechanical mixer is shown in US patent specification no. 5,738,439 having a single rotatable shaft and radially extending arms with mixing paddle members at the free ends of the arms. The specification discloses a mixing vessel with a rectangular upper zone when viewed in plan view with vertical side and end walls. The lower region has a generally semicircular bottom wall merging into the vertical side walls of the upper zone with the upper end walls being extended in the same vertical plane to close the end zones of the lower region. A discharge opening leads from a lower portion of the lower region and the vessel is loaded through the upper rectangular face of the vessel.

[0004] While such known arrangements are effective, in practice they do require significant space, both vertically and horizontally, to be operationally mounted and are therefore, relatively costly establishments.

[0005] The objective of the present invention is to provide an improved mixing apparatus of the above discussed type that will allow effective mixing of two or more materials without requiring the cost and space of existing mixing equipment of this kind.

SUMMARY OF THE INVENTION

[0006] According to one aspect, the present invention provides mixing apparatus including a mixing vessel having a horizontally disposed hollow cylindrical body with opposed torispherical ends forming a substantially enclosed internal mixing zone, said torispherical ends and said hollow cylindrical body each having an inwardly facing surface that merge smoothly into one another, a rotatable shaft rotatable about a horizontal rotation axis, said rotatable shaft having a plurality of mixing paddle members extending laterally from said rotatable shaft having free end zones spaced inwardly from the inwardly facing surface of said mixing vessel, drive means for driving said rotatable shaft, first connection means for connecting said internal mixing zone to a vacuum or pressure source to create condition conducive to moving one or more materials to be mixed to said internal mixing zone, second connection means for introducing at least one material to be treated into said internal mixing zone, in use, via vacuum or pressure means, and discharge means leading from a lower most zone of said internal mixing zone, said discharge means including a discharge closure member positionable at or adjacent said inwardly facing surface of internal mixing zone when located in a closed position.

[0007] Preferred features of the aforesaid mixing apparatus may be as defined in claims 2 to 13 inclusive as annexed hereto, the subject matter of these claims is made part of the disclosure of the present specification by this reference thereto.

[0008] The term "torispherical" is used in the foregoing and in the annexed claims to identify walls of a pressure vessel where the ends provide a continuous curved extension of the cylindrical walls forming the central part of the vessel. The ends may have an ellipsoidal form or a hemispherical form but should not be seen to be limited to either. The walls of the mixing vessel need to provide a smooth substantially continuous inner surface such that materials being mixed do not build up in any discontinuities or sharp corners such that mixing and cleaning might be improved. The mixing vessel does also need to be able to resist pressure applied either by pressurized air supplied or by atmospheric pressure because of the vacuum conditions created for loading materials to be mixed into the mixing zones.

[0009] In a preferred embodiment, two mixing apparatus of the above described type might be used in a mixing installation. The internal mixing zone of each mixing apparatus is sequentially placed in vacuum conditions or provided with pressurized air such that one such mixing apparatus is loaded thereby with materials to be mixed while the other is discharged of a previously mixed load of materials. Subsequently, the roles of the mixing apparatus are reversed such that a semi continuous operation can be created.

[0010] Further preferred aspects of the present invention will become apparent from the following description given in relation to preferred embodiments illustrated in the annexed drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[001 1 ] Fig 1 is a perspective view of one preferred embodiment of the vacuum mixing apparatus from its drive end;

[0012] Fig 2 is a top plan view of Fig 1 ;

[0013] Fig 3 is an illustrative partial cross-sectional view along line C-C of Fig 2 showing details of the nozzle adapted to supply cleaning fluid;

[0014] Fig 4 is a side elevation view of the apparatus shown in Fig 1 ;

[0015] Fig 4a is an enlarged detail view of the discharge zone of the mixing apparatus shown in Fig 4;

[0016] Fig 5 is a perspective view of the discharge valve shown in Figs 4 and 4a;

[0017] Fig 5a is a side elevation view of the discharge valve shown in Fig 5 with the closure plate in several possible positions from closed to open;

[0018] Fig 5b is an underneath plan view of the outer side of the discharge valve shown in Fig 5;

[0019] Fig 5c is a side elevation view of the discharge valve 90° transposed from the view shown in Fig 5a;

[0020] Fig 5d is a section view along line C-C of Fig 5b;

[0021 ] Fig 5e is a section view along lines B-B of Figs 5c or 5d; [0022] Fig 6 is an end elevation view of the mixing apparatus shown in Fig 1 from the non-drive end;

[0023] Fig 6a is a detailed view of the area marked "A" in Fig 6;

[0024] Fig 7 is a perspective view of the rotatable mixer shaft with the mixing paddles mounted thereto;

[0025] Fig 8 is an end elevation view of the arrangement shown in Fig 7;

[0026] Fig 9 is a side elevation view of the arrangement shown in Fig 7; and

[0027] Fig 10 is a schematic system drawing of one possible mixing installation utilizing two mixing apparatus as shown in Figs 1 to 9.

[0028] Referring to Figs 1 to 9, mixing apparatus is provided having a mixing vessel 1 1 with a cylindrical centre shell part 12 with opposed torispherical end parts 13, 14. The mixing vessel 1 1 is supported on spaced leg structures 15, 16. The mixing vessel 1 1 has an inner enclosed mixing space 17 occupied by a rotatable shaft 18 with mixing paddles 19. Each of the mixing paddles 19 comprises a radial or laterally extending arm 20 with a paddle plate 21 at its free end. The rotatable shaft 18 and mixing paddles 19 are best seen in Figs 7, 8 and 9. The shape, angle and configuration of the paddle plates 21 are such as to promote mixing and movement of the materials to be mixed in the vessel 1 1 . Some, at least, of the paddle plates 21 are adapted to move close to the inwardly facing wall of the mixing vessel 1 1 and as such, it is desirable that no parts of the mixing apparatus 10 other than the shaft 18 and mixing paddles 19 extend significantly into the internal mixing space 17. The rotatable shaft 18 extends along the horizontal axis 22 of the vessel 1 1 and is supported at one end by a suitable bearing structure 23 and at the other end by a bearing structure 24, with the shaft 18 being driven by a drive arrangement 25 comprising a drive motor 26 and gear train 27. [0029] The mixing vessel 1 1 has a first connection means 28 enabling the internal mixing zone 17 to be connected to a vacuum creating source such that, when desired, vacuum conditions can be established in the inner mixing zone 17. Alternatively, the internal mixing zone 17 might have a source of pressurized air to enable materials to be mixed to be transported thereto. The purpose of this is further explained in the following. The mixing vessel further includes at least one and conveniently two or more second connection means 29, 30 enabling the inlets to be connected to a line that may deliver a material to be mixed into the inner mixing zone 17. This may be a storage hopper for the material or simply a bulk holding bag for the material, however, neither needs to be elevated as the material is not delivered by gravity but rather by vacuum conditions or by pressure conditions established in or supplied to the zone 17 and communicated along the delivery pipe, conduit or the like. The material might be one or more dry particulate materials such that a dry blended particulate product can be made by mixing in the internal mixing zone. If the product to be produced is a liquid or semi liquid product then one or more of the materials to be added may be a liquid or more than one liquid. Conveniently, some form of metering means would also be provided to ensure precise amounts of material to be mixed are delivered to the mixing zone 17 by the vacuum formed therein. The metering means may be some form of weighing apparatus such as, but not limited to, load cells to weigh a material added to the mixing zone. The weighing apparatus would be arranged to stop introduction of the material being introduced once the weight sensed is indicative of a predetermined quantity of the desired material has been introduced into the mixing zone.

[0030] Preferably, the mixing apparatus 10 also includes nozzles 31 in a frusto conical extension 32 of the wall of the mixing chamber 12 so as to be able to spray any desired fluid 33 into the inner mixing chamber 17 when it is desired to do so. As shown in Figs 1 and 3, two such nozzles 31 in the extensions 32 may be utilized spaced along the length of chamber wall 12. The fluid 33 may be a liquid to be admixed to the materials being mixed in the internal mixing zone. In another possible arrangement the fluid 33 might be a cleaning fluid once the desired mixing of materials has been completed. In such a case, the nozzle 31 might need to be varied. As is shown in Figs 1 , 2, 4 and 6, at least one and preferably two access ports 34 are provided in the chamber wall 12 along a side region. The ports 34 provide ease of access for an operator to the inner mixing zone 17 when such access is required. The ports 34 are openable or closeable by doors 35 that are sealed to the chamber wall 12 when closed to prevent escape of any of the materials being mixed. As best seen in Figs 4, 4a, 5 and 5a to 5e, a discharge valve arrangement 36 is provided underneath the chamber wall 12 adapted to close or open a discharge opening 45 formed in the wall of the mixing zone 17. The discharge opening 45 enables mixed material to be discharged by gravity or potentially also via vacuum line or other suitable discharge conveying means. The discharge valve arrangement 36 includes a plate part 37 having an inwardly facing surface 38 that is arcuate in form and approximates a continuance of the inwardly facing surface of the mixing zone 17 when in the closed position. An actuating arm 39 is secured centrally to the plate part 37 (as shown in Figs 5a, 5b and 5e) with the free end being connected to a rotatable shaft 40 connected to an actuator motor 41 such that the plate part 37 can be moved from the closed position shown as 42 in Fig 5a to the fully open position 43 also shown in Fig 5a. As is apparent from Fig 5a, the plate part 37 does not enter the mixing zone 17 when open, closed or any position in between. The assembly of the discharge valve arrangement 36 is mountable to and demountable from the discharge opening 45 by means of depending mounting arms 46 each with a swinging threaded bolt 47 with a rotatable wing nut 48 cooperable with recesses 49 in a mounting plate 50. Demounting of the discharge valve arrangement 36 enables it to be thoroughly cleaned and sterilized (from time to time), if required.

[0031 ] Fig 10 illustrates a possible mixing installation including two mixing devices 10 and 10' as, for example, described above with reference to Figs 1 to 9. Each of the mixing devices 10 and 10' are connected via a line 45 and respective valves 46, 47 to a vacuum source or the like 48. In this manner the inner mixing chamber 17, 17' of the mixing devices 10 and 10' can selectably be placed into a state of vacuum or have the vacuum state returned to atmospheric air pressure selectably as described hereafter. Alternatively, pressurized air might selectably be used to transport a material, or materials to be mixed. One or more sources of material to be mixed can be supplied via line 49 and valves 50, 51 selectably to each of the mixing chambers 17, 17'. The mixing chambers 17, 17' may be vented, when required via lines 52, 53 and valves 54, 55. Each of the mixed contents of the mixing chambers 17 of the mixing devices 10 and 10' may be discharged via discharge valves 36, 36' either gravitationally or to a discharge line 56, for example connected to a vacuum source. While mixer 10' is discharging to the next stage via line 56 with the vent 55 open and the vacuum valve 46 open. The required amount of material to be mixed will then be introduced into the mixing zone 17 with its discharge valve 36 closed. When the required content is received in the mixing zone 17, the inlet valve 50 is closed (with the discharge valve 36 also closed) and the contents in mixing zone 17 is mixed. Once the mixer device 10' is emptied, the functions are reversed providing a possibility of a semi continuous process.

[0032] Those skilled in the art will appreciate that further modifications of the apparatus and installation may be made without departing from the contents set out in the annexed claims.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1 . Mixing apparatus including a mixing vessel having a horizontally disposed hollow cylindrical body with opposed torispherical ends forming a substantially enclosed internal mixing zone, said torispherical ends and said hollow cylindrical body each having an inwardly facing surface that merge smoothly into one another, a rotatable shaft rotatable about a horizontal rotation axis, said rotatable shaft having a plurality of mixing paddle members extending laterally from said rotatable shaft having free end zones spaced inwardly from the inwardly facing surface of said mixing vessel, drive means for driving said rotatable shaft, first connection means for connecting said internal mixing zone to a vacuum or pressure source to create a condition conducive to moving one or more materials to be mixed to said internal mixing zone, second connection means for introducing at least one material to be treated into said internal mixing zone, in use, via vacuum or pressure means, and discharge means leading from a lower most zone of said internal mixing zone, said discharge means including a discharge closure member positionable at or adjacent said inwardly facing surface of internal mixing zone when located in a closed position.

2. Mixing apparatus according to claim 1 wherein said horizontal rotation axis is coincident with a horizontal axis of said hollow cylindrical body.

3. Mixing apparatus according to claim 1 or claim 2 wherein said discharge closure member is selectably moveable to an open position to enable mixed contents in said internal mixing zone to be discharged therefrom, said closure member not extending into said internal mixing zone when being moved to or located in said open position.

4. Mixing apparatus according to claim 3 wherein said rotatable shaft continues to rotate as said mixed contents are discharged through said discharge means.

5. Mixing apparatus according to any one of claims 1 to 4 wherein said second connection means enables at least two substantially dry particulate materials separately into said internal mixing zone.

6. Mixing apparatus according to claim 5 wherein said second connection means enables at least one liquid or semi liquid material to be introduced into said internal mixing zone.

7. Mixing apparatus according to claim 5 or claim 6 further including metering means to meter precise quantities of materials into said internal mixing zone.

8. Mixing apparatus according to claim 7 wherein said metering means includes weight measuring means for measuring weight of a material introduced into the internal mixing zone, said weight measuring means acting to discontinue introduction of said material when a predetermined weight introduced has been sensed.

9. Mixing apparatus according to claim 8 wherein said weight measuring means includes one or more load cells.

10. Mixing apparatus according to any one of claims 1 to 9 wherein each said mixing paddle member extending laterally from said rotatable shaft includes a laterally extending arm and at least one paddle plate located at a distal end of the laterally extending arm.

1 1 . Mixing apparatus according to any one of claims 1 to 10 further including support leg means to elevate said discharge means.

12. Mixing apparatus according to any one of claims 1 to 1 1 further including cleaning fluid nozzle means including third connecting means for connecting said cleaning fluid nozzle means to a source of cleaning fluid, said cleaning fluid nozzle means being mounted to said mixing apparatus to direct a cleaning fluid stream into said internal mixing zone.

13. Mixing apparatus according to claim 12 wherein said cleaning fluid nozzle means includes at least one nozzle positioned outwardly of an upper zone of said inwardly facing surface of said internal mixing zone, the or each said nozzle being arranged to express a nozzle spray through an opening in a wall of said hollow cylindrical body, the or each said nozzle being supported by a frustoconical wall structure surrounding said opening in the wall of the hollow cylindrical body.

14. Mixing apparatus according to any one of claims 1 to 13 further including at least one access port in a side wall region of the mixing vessel, the or each said access port being openable or closable by a door part arranged to seal a said access port when closed whereby an inner surface of the door part provides substantially a continuance of the inwardly facing surface of the internal mixing zone.

15. Mixing apparatus according to claim 14 wherein two said access ports are provided in the hollow cylindrical body.

16. A mixing installation including at least two mixing apparatus according to any one of claims 1 to 15, vacuum creating means connectible to the internal mixing zone of each said mixing apparatus, first valve means for establishing vacuum conditions selectably in at least one of said internal mixing zones while a second said internal mixing zone is disconnected from vacuum conditions, communication means for connecting said at least one said internal mixing zone to at least one source of material to be mixed and moving said material or materials to said at least one said internal mixing zone in response to said vacuum conditions therein.

17. A mixing installation including at least two mixing apparatus according to any one of claims 1 to 15, pressure air flow means provided to deliver at least one material to be mixed to the internal mixing zone of each said mixing apparatus, first valve means enabling said pressure air flow means to deliver one or more said materials to a first one of said internal mixing zones while preventing flow to the other of said internal mixing zones, said discharge means including a first discharge valve leading from said first internal mixing zone and a second discharge valve leading from said other internal mixing zone.

18. A mixing installation according to claim 16 or claim 17 further including at least one metering means for metering the material or materials into said at least one internal mixing zone.

19. A mixing installation according to any one of claims 16 to 18 wherein a said discharge means leading from the second said internal mixing zone is open to discharge contents that have been mixed while material or materials are loaded into said one internal mixing zone to be mixed.