METHOD OF OPERATING A BATCH MIXER AND BATCH MIXER FOR PERFORMING THE METHOD

Abstract

The invention provides a method of operating a batch mixer for producing first and second numbers of mixtures from first and second numbers of batches of materials to be mixed in the batch mixer, the batch mixer comprising a mixing chamber, a mixing element disposed within the mixing chamber, the mixing element and the mixing chamber being configured for providing an identical flow of the materials to be mixed within the mixing chamber and around the mixing element regardless of in which of the first and second opposite directions the mixing element is rotated, and a motor assembly coupled to the mixing element for rotating the mixing element for mixing the first and second numbers of batches of materials to be mixed for producing the first and second numbers of mixtures. The method comprises the steps of energizing said motor assembly for rotating said mixing element in said first direction, for each one of the first number of batches of the materials to be mixed: loading the one of the first number of batches of materials to be mixed into the mixing chamber, mixing the one of the first number of batches of materials for producing one of the first number of mixtures, and removing the one of the first number of mixtures from the mixing chamber, energizing the motor assembly for rotating the mixing element in the second direction, and for each one of the second number of batches of the materials to be mixed loading the one of the second number of batches of materials to be mixed into the mixing chamber, mixing the one of the second number of batches of materials for producing one of the second number of mixtures, and removing the one of the second number of mixtures from the mixing chamber.

Claims

1-12. (canceled)

13. A method of operating a batch mixer for producing first and second numbers of mixtures from first and second numbers of batches of materials to be mixed in said batch mixer, said batch mixer comprising: a mixing chamber, a mixing element disposed within said mixing chamber, said mixing element and said mixing chamber being configured for providing an identical flow of said materials to be mixed within said mixing chamber and around said mixing element regardless of in which of the first and second opposite directions said mixing element is rotated, said mixing element comprising at least two mixing paddles for mixing said materials to be mixed, said mixing paddles being arranged in said mixing element such that rotation of said mixing element, in either of said first direction or said second direction, causes said materials to be mixed to flow, at the same rate regardless of the direction of rotation, towards the centre of said mixing chamber or alternatively towards the opposite ends of said mixing chamber, each of said mixing paddles comprising a closed elongated prism having a first face orthogonal to the axis of rotation of said mixing element and second and third faces forming first and second identical angles to said first face, and a motor assembly coupled to said mixing element for rotating said mixing element for mixing said first and second numbers of batches of materials to be mixed for producing said first and second numbers of mixtures, the method comprising the steps of: energizing said motor assembly for rotating said mixing element in said first direction, for each one of said first number of batches of said materials to be mixed: loading said one of said first number of batches of materials to be mixed into said mixing chamber, mixing said one of said first number of batches of materials for producing one of said first number of mixtures, and removing said one of said first number of mixtures from said mixing chamber, energizing said motor assembly for rotating said mixing element in said second direction, and for each one of said second number of batches of said materials to be mixed: loading said one of said second number of batches of materials to be mixed into said mixing chamber, mixing said one of said second number of batches of materials for producing one of said second number of mixtures, and removing said one of said second number of mixtures from said mixing chamber.

14. The method according to claim 13, wherein the steps of the method are performed for a plurality of said first number of batches of materials to be mixed and for a plurality of said number of second batches of materials to be mixed.

15. The method according to claim 13, wherein said first and second numbers of batches comprise the same composition and amounts of materials to be mixed.

16. The method according to claim 13 wherein said materials to be mixed comprise ingredients for producing animal feed.

17. The method according to claim 13, wherein said batch mixer comprises an upper inlet fluidly connected to said mixing chamber for admitting said first and second numbers of batches of material to be mixed into said mixing chamber, said batch mixer further comprising at least one injection nozzle for injecting at least one additive into said mixing chamber, said injection nozzle being provided in or on the wall of said upper inlet, said method further comprising the steps of: injecting said additive into said mixing chamber from said injection nozzle for mixing said additive with at least one of said first number of batches, and injecting said additive into said mixing chamber from said injection nozzle for mixing said additive with at least one of said second number of batches, and wherein the steps of loading said one of said first and second numbers of batches of materials to be mixed into said mixing chamber comprise loading each of said first and second numbers of batches of materials into said mixing chamber through said upper inlet such that said materials to be mixed flow around and past said injection nozzle for at least partially removing any deposit of said materials to be mixed or said first or second number of mixtures from said injection nozzle.

18. The method according to claim 13, wherein the duration, rotational speed and/or intensity of rotation of said mixing element in said first direction is the same as the duration, rotational speed and/or intensity of rotation of said mixing element in said second direction.

19. A batch mixer for producing first and second numbers of mixtures from first and second numbers of batches of materials to be mixed in said batch mixer, said batch mixer comprising a mixing chamber, a mixing element disposed within said mixing chamber, said mixing element and said mixing chamber being configured for providing an identical flow of said materials to be mixed within said mixing chamber and around said mixing element regardless of in which of the first and second opposite directions said mixing element is rotated, said mixing element comprising at least two mixing paddles for mixing said materials to be mixed, said mixing paddles being arranged in said mixing element such that rotation of said mixing element, in either of said first direction or said second direction, causes said materials to be mixed to flow, at the same rate regardless of the direction of rotation, towards the centre of said mixing chamber or alternatively towards the opposite ends of said mixing chamber, each of said mixing paddles comprising a closed elongated prism having a first face orthogonal to the axis of rotation of said mixing element and second and third faces forming first and second identical angles to said first face, and a motor assembly coupled to said mixing element for rotating said mixing element for mixing said first and second numbers of batches of materials to be mixed for producing said first and second numbers of mixtures, said batch mixer further comprising: a control device for energizing said motor assembly for rotating said mixing element in said first direction for producing said first number of mixtures, and for energizing said motor assembly for rotating said mixing element in said second direction for producing said second number of mixtures, said control device preferably further being configured for causing said motor assembly to rotate said mixing element with equal duration, rotational speed and/or intensity of rotation in both of said first and second directions of rotation.

20. The batch mixer according to claim 19, said first and second identical angles being 30° to 80°, more preferably 45° to 70°, and most preferably 60°.

21. The batch mixer according to claim 20, said mixing element comprising a mixer shaft having first and second opposite ends, said mixing element further comprising at least 4 mixing paddles arranged in first and second groups of two each, the mixing paddles of said first group being positioned closest to said second end of said mixer shaft and oriented for causing said materials to be mixed to flow towards said first end, and the mixing paddles of said second group being positioned closest to said first end of said mixer shaft and oriented for causing said materials to be mixed to flow towards said second end.

22. The batch mixer according to claim 19, said batch mixer comprising an upper inlet fluidly connected to said mixing chamber for admitting said first and second numbers of batches of material to be mixed into said mixing chamber, said batch mixer further comprising at least one injection nozzle for injecting at least one additive into said mixing chamber, said injection nozzle being provided in or on the wall of said upper inlet such that said materials to be mixed flow around and past said injection nozzle when being loaded into said mixing chamber for at least partially removing any deposit of said materials to be mixed or said first or second number of mixtures from said injection nozzle.

23. The batch mixer according to claim 19, said batch mixer comprising an inspection and cleaning opening, said injection and cleaning opening being provided on one end of said mixing chamber.

24. The batch mixer according to claim 23, said batch mixer comprising a swivable housing part on said one end of said mixing chamber, said swivable housing part being swivable around a pivot axis from a closed position, in which the majority of said swivable housing part is provided above said pivot axis exposing a first side of said swivable housing part, to an open position in which said majority of said swivable housing part is provided below said pivot axis for revealing a second side of said swivable housing part, said second side being opposite to said first side and comprising steps for allowing an operator of said batch mixer to ascend said steps for accessing said inspection and cleaning opening or for accessing said upper inlet.

25. The method according to claim 14, wherein said first and second numbers of batches comprise the same composition and amounts of materials to be mixed.

26. The method according to claim 14, wherein said materials to be mixed comprise ingredients for producing animal feed.

27. The method according to claim 15, wherein said materials to be mixed comprise ingredients for producing animal feed.

28. The method according to claim 14, wherein said batch mixer comprises an upper inlet fluidly connected to said mixing chamber for admitting said first and second numbers of batches of material to be mixed into said mixing chamber, said batch mixer further comprising at least one injection nozzle for injecting at least one additive into said mixing chamber, said injection nozzle being provided in or on the wall of said upper inlet, said method further comprising the steps of: injecting said additive into said mixing chamber from said injection nozzle for mixing said additive with at least one of said first number of batches, and injecting said additive into said mixing chamber from said injection nozzle for mixing said additive with at least one of said second number of batches, and wherein the steps of loading said one of said first and second numbers of batches of materials to be mixed into said mixing chamber comprise loading each of said first and second numbers of batches of materials into said mixing chamber through said upper inlet such that said materials to be mixed flow around and past said injection nozzle for at least partially removing any deposit of said materials to be mixed or said first or second number of mixtures from said injection nozzle.

29. The method according to claim 15, wherein said batch mixer comprises an upper inlet fluidly connected to said mixing chamber for admitting said first and second numbers of batches of material to be mixed into said mixing chamber, said batch mixer further comprising at least one injection nozzle for injecting at least one additive into said mixing chamber, said injection nozzle being provided in or on the wall of said upper inlet, said method further comprising the steps of: injecting said additive into said mixing chamber from said injection nozzle for mixing said additive with at least one of said first number of batches, and injecting said additive into said mixing chamber from said injection nozzle for mixing said additive with at least one of said second number of batches, and wherein the steps of loading said one of said first and second numbers of batches of materials to be mixed into said mixing chamber comprise loading each of said first and second numbers of batches of materials into said mixing chamber through said upper inlet such that said materials to be mixed flow around and past said injection nozzle for at least partially removing any deposit of said materials to be mixed or said first or second number of mixtures from said injection nozzle.

30. The method according to claim 16, wherein said batch mixer comprises an upper inlet fluidly connected to said mixing chamber for admitting said first and second numbers of batches of material to be mixed into said mixing chamber, said batch mixer further comprising at least one injection nozzle for injecting at least one additive into said mixing chamber, said injection nozzle being provided in or on the wall of said upper inlet, said method further comprising the steps of: injecting said additive into said mixing chamber from said injection nozzle for mixing said additive with at least one of said first number of batches, and injecting said additive into said mixing chamber from said injection nozzle for mixing said additive with at least one of said second number of batches, and wherein the steps of loading said one of said first and second numbers of batches of materials to be mixed into said mixing chamber comprise loading each of said first and second numbers of batches of materials into said mixing chamber through said upper inlet such that said materials to be mixed flow around and past said injection nozzle for at least partially removing any deposit of said materials to be mixed or said first or second number of mixtures from said injection nozzle.

31. The method according to claim 14, wherein the duration, rotational speed and/or intensity of rotation of said mixing element in said first direction is the same as the duration, rotational speed and/or intensity of rotation of said mixing element in said second direction.

32. The method according to claim 15, wherein the duration, rotational speed and/or intensity of rotation of said mixing element in said first direction is the same as the duration, rotational speed and/or intensity of rotation of said mixing element in said second direction.

Description

[0068] The invention and its many advantages will be described in more detail below with reference to the accompanying schematic drawings, which for the purpose of illustration show some non-limiting embodiments, and in which:

[0069] FIG. 1 shows, in perspective view, a first embodiment of a batch mixer according to the second aspect of the present invention,

[0070] FIGS. 2A and 2B show, in cross section, the first embodiment of the batch mixer according to the second aspect of the present invention performing the first embodiment of the method according to the first aspect of the present invention,

[0071] FIGS. 3A and 3B show, respectively, in perspective view and end view, a mixing element used in the batch mixer according to the second aspect of the present invention, and

[0072] FIGS. 4A and 4B show, in perspective view, the first embodiment of the batch mixer according to the second aspect of the present invention.

[0073] In the below description, one or more ′signs added to a reference number indicate that the element referred to has the same or similar function as the element designated the reference number without the ′sign, however, differing in structure.

[0074] Additionally, where useful for discussing two or more identical elements, a subscript Arabic numeral is used to designate such further identical elements.

[0075] When further embodiments of the invention are shown in the figures, the elements which are new, in relation to earlier shown embodiments, have new reference numbers, while elements previously shown are referenced as stated above. Elements which are identical in the different embodiments have been given the same reference numerals and no further explanations of these elements will be given.

[0076] FIG. 1 shows, in perspective view, a first embodiment of a batch mixer 10 according to the second aspect of the present invention. The batch mixer 10 comprises a chassis 12 for supporting the batch mixer 10. On one end of the chassis 12 is attached a first frame part 14. The chassis 12 further supports a cylindrical mixing chamber 16 which is provided between the frames 14. Above the mixing chamber 16 is provided an inlet housing 18. The inlet housing 18 extends between the first and second frame parts 14 and 20. Inside the inlet housing 18 is provided an upper inlet 50, shown in FIGS. 2 and 4, for establishing fluid communication between the exterior of the batch mixer 10 and the interior of the mixing chamber 16 for allowing a batch of materials to be mixed to be introduced into the mixing chamber 16.

[0077] Attached to the first frame part 14 is a motor assembly comprising an electric motor 22 and a gear box 24. Mixing chamber 16 further comprises a first end 26 and a second opposite end 28.

[0078] Turning to FIGS. 2A and 2B it can be seen that the bottom of the mixing chamber 16 comprises an outlet gate 30 which can be pivoted open to empty the mixing chamber 16 of its contents, i.e. the mixed material, once mixing has been completed.

[0079] Turning briefly to FIGS. 4A and 4B it can be seen that batch mixer 10 further comprises a swivable housing part 32 forming part of the second frame part 20 opposite the electric motor 22 and the gear box 24. The swivable housing part 32 comprises a first, outer side 34 and an opposite second, inner, side 36. On the second side are provided steps, one of which is designated the reference numeral 38. The swivable housing part 32 is hinged to be swivable around a horizontal pivot axis 40 for exposing the second side 36 and the steps 38. Using the steps 38 an operator 2 of the batch mixer 10 may easily climb up the steps 38 and inspect the interior of the mixing chamber 16 through an inspection and cleaning opening 42 provided in the second end 28 of the batch mixer 10. When the batch mixer 10 is running, a cover 48 is used to close the inspection and cleaning opening 42. This cover may be integral with the second side 36 of the swivable housing part 32 or may be a separate piece, or is as here shown attached to the batch mixer 10 in the manner of a hatch or door.

[0080] FIG. 4B further shows a bearing 44 attached to the second end 28 of the mixing chamber. Turning briefly to FIG. 1 a control device 46 is connected to the electric motor 22 for driving the motor each of the two directions A and B.

[0081] Returning now to FIGS. 2A and 2B it can be seen that an injection nozzle 52, for injecting liquid additives to the materials to be mixed, is provided in the upper inlet 50. The positioning of the injection nozzles 52 in the upper inlet 50 has the advantage that any material to be mixed, or mixed material, deposited on the injection nozzles 52 from mixing a batch in the batch mixer 10 is scrubbed off the injection nozzles 52 as the materials to be mixed of the next batch is allowed to fall through the upper inlet 50 into the mixing chamber 16.

[0082] The batch mixer 10 further comprises a mixing element, in its entirety designated the reference numeral 60, disposed within the mixing chamber 16. The mixing element 60, shown in FIGS. 2A to 3B, comprises a mixer shaft 62 having a first end 62 attached to the gear box 24 and a second, opposite, end 66 journaled in the bearing 44. The mixing shaft 62 carries six paddle assemblies, one of which in its entirety is designated the reference numeral 70 and which represents a mixing paddle. The paddle assembly 70 comprises an elongated paddle shaft 72 attached to the mixing shaft 62 via a fastening mechanism. The paddle shaft 72 extends radially out from the fastening mechanism 74 around the mixer shaft 62 to a paddle head 76, 76 also referencing the triangular end face of the paddle assembly 70, being prism-shaped and having first, second and third paddle faces 78, 80 and 82. The paddle head 76 is oriented so that the first paddle face 78 is orthogonal to the mixer shaft 62 and turned towards the second end 66 while the second and third paddle faces 80 and 82 are partly turned towards the first end 64 of the mixer shaft 62 and form angles of 60° to the first face 78. Thus, whichever direction the mixer shaft 62 is turning, A or B, one or the other of the paddle faces 80 and 82 will force the materials to be mixed towards the centre of the mixing chamber 16.

[0083] The paddle faces 78, 80, and 82 are formed of flat steel plates.

[0084] The six paddle assemblies 70 are arranged in two groups of three paddle assemblies whereby the first group comprising the paddle assembly 70 in the figures and being closest to the second end 66 of the mixer shaft 62, during rotation of the mixer shaft forces the material towards the first end 64 of the mixer shaft 62. The second group of three paddle assemblies is positioned closest to the first end 64 of the mixer shaft and includes the paddle assembly 70.sub.1 which is identical to the paddle assembly 70 but which is turned 180° in relation to the paddle assembly 70. The paddle assembly 70.sub.1 therefore has its first paddle face 78.sub.1 turned towards the first end 64 and its second and third paddle faces 80.sub.1 and 82.sub.1 turned towards the second end 64 of the mixer shaft 62 and forms angles of +60° to the first paddle face 78.sub.1. Thus, whichever direction the mixer shaft 62 is turning, A or B, one or the other of the paddle faces 80.sub.1 and 82.sub.1 will force the materials to be mixed towards the centre of the mixing chamber 16.

[0085] As there are a symmetrical number of paddle assemblies on the two groups, and as the second and third paddle faces 80, 80.sub.1 and 82, 82.sub.1 form identical angles to the first paddle face 78, 78.sub.1, the mixing effect of the batch mixer 10 is the same regardless of the direction of rotation.

[0086] Each three paddles assemblies in each of the two groups are positioned staggered 60° in a spiral around the mixer shaft 62. This allows the full length of the inner side of the wall of the mixing chamber 16 to be swept by the paddle assemblies for eliminating any spots where materials to be mixed or mixed materials could accumulate.

[0087] Turning to FIGS. 2A and 2B the method according to the first aspect of the present invention is demonstrated for the case where the number of first and second batches are 1, i.e. when a first batch is mixed in a first direction and a second batch is mixed in the opposite second direction.

[0088] 1. Firstly, shown in FIG. 2A, the electric motor 22 is energized for rotating the mixing element 60 in the A direction.

[0089] 2. A first batch of materials to be mixed is admitted into the mixing chamber 16 through the upper inlet 50. Any liquid additives needed are then admitted into the mixing chamber 16 through the injection nozzle 52.

[0090] 3. The first batch of materials to be mixed is mixed as the mixing element 60 rotates in the A direction to produce the first mixture.

[0091] 4. The first mixture is removed from the mixing chamber 16 through the gate outlet 30 which is opened allowing the mixed materials of the first batch to be discharged from the mixing chamber 16.

[0092] At this point there may have formed deposits of materials to be mixed or mixed materials from the first batch. These deposits may for example form on the second paddle face 80 of the paddle assembly 70 and the third paddle face 82.sub.1 of the paddle assembly 70.sub.1 as these faces have not engaged the materials to be mixed. Deposits may further have formed on the injection nozzle 52 or in the upper inlet 50.

[0093] 5. Now, as shown in FIG. 2B, the electric motor 22 is once more energized, this time however for rotating the mixing element 60 in the opposite direction B.

[0094] 6. A second batch of materials to be mixed is admitted into the mixing chamber 16 through the upper inlet 50. As this second batch of materials to be mixed is allowed to fall into the mixing chamber 16 through the upper inlet 50, the materials to be mixed hit any deposits in the upper inlet 50 or on the injection nozzle 52 and by the force of the impact entrain these deposits and thus clear the injection nozzle 52 and the upper inlet 50 of the deposits.

[0095] Any liquid additives needed are then admitted into the mixing chamber 16 through the injection nozzle 52.

[0096] 7. The second batch of materials to be mixed is then mixed as the mixing element 60 rotates in the B direction to produce the second mixture.

[0097] As the mixing element 60 now turns in the B direction, the second paddle face 80 of the paddle assembly 70 and the third paddle face 82.sub.1 of the paddle assembly 70.sub.1 will now engage the material to be mixed of the second batch whereby the friction between the materials to be mixed and the second paddle face 80 and the third paddle face 82.sub.1 now causes any deposits formed during the mixing of the first batch to be removed or scrubbed off the paddle faces 80 and 82.sub.1.

[0098] 8. Finally the gate outlet 30 is once more opened to allow the mixed material of the second batch to fall through the outlet gate.

[0099] To ensure that the mixing of each batch is identical the duration and intensity of rotation should be the same in each of the directions A and B.

[0100] If first and second numbers of batches are to be mixed, steps 2-4 and 6-8 are repeated for each of the number of first and second batches.

[0101] As is evident from the above, the batch mixer 10 is at least partially self-cleaning in operation because any deposits formed during mixing of a first number of batches are removed during the mixing of a second number of batches or during the loading of each of the first number of batches or vice versa.

[0102] Furthermore, as the mixing effect of the batch mixer 10 is the same regardless of the direction of rotation, each batch is mixed identically providing reproducible mixing. The batch mixer 10 may be operated for a long time and a large plurality of batches without needing cleaning, thus increasing productivity of the batch mixer 10.

LIST OF PARTS WITH REFERENCE TO THE FIGURES

[0103]

TABLE-US-00001 A. Arrows indicating rotation in a first direction B. Arrows indicating rotation in a second direction 2. Operator 10. Batch mixer 12. Chassis 14. First frame part 16. Mixing chamber 18. Inlet cover 20. Second frame part 22. Electric motor 24. Gear box 26. First end of mixing chamber 28. Second end of mixing chamber 30. Outlet gate 32. Swivable housing part 34. First side of swivable housing part 36. Second side of swivable housing part 38. Steps 40. Pivot axis 42. Inspection and cleaning opening 44. Bearing 46. Control device 48. Inspection and cleaning opening cover 50. Upper inlet 52. Injection nozzle 60. Mixing element 62. Mixer shaft 64. First end of mixer shaft 66. Second end of mixer shaft 70. Paddle assembly 72. Paddle shaft 74. Fastening mechanism 76. Paddle head 78. First paddle face 80. Second paddle face 82. Third paddle face