GB2260712A - A mixing or separating machine - Google Patents

Abstract

A machine for mixing materials such as paints, clays, sands, Figure 1, comprises a container (1) with an inlet substantially upright auger (2). The auger (2) is coupled to a drive mechanism (5) capable of rotating it to transport material upwardly within the container (1). A sleeve (6) is located around the auger (2) to define a first chamber (8) and a second chamber (9) which communicates above the auger to allow circulation of the materials. The mixed materials may be extruded through a perforated plate (18) on reversal of the auger rotation. The sleeve (6) may be closed at its ends by perforated plates or grids and may contain grinding beads. A smear plate may be located at the top of the sleeve (6), and a plough (19, Fig 2, not shown) at the bottom. Several machines may be linked in cascade arrangement. The machine can also be used for separating aggregates or liquid/solid mixtures such as slurries, Figure 4, by communicating the outer cavity (9) with the inner cavity (8) via perforations or apertures in the sleeve (6) and/or via a perforated plate or grid closing the sleeve (6) at the top, through which perforations or apertures only the liquid or small particles of the mixture can pass. <IMAGE>

Description

A MIXING OR SEPARATING MACHINE The present invention relates to a machine for mixing materials which, with a small addition makes it also suitable for separating aggregates and liquid/solid mixtures.

Conventionally, mixing machines comprise a container into which the materials to be mixed are introduced through a top opening and in which is located an agitator.

The agitator can be of various constructions; typically it comprises paddles or a spiral blade mounted on a rotating shaft. After agitation, the resulting mixture is usually discharged via a bottom opening in the container or tipped out through the top opening. Disadvantages of mixers such as these are that it can take considerable agitation to achieve a homogeneous mixture, particularly with materials which are sticky or have a high viscosity; that excessive agitation required to achieve a homogeneous mixture can cause damage to delicate materials; and that they require filling from the top necessitating the use of conveyors, elevators and the like when the mixer is built to a large scale.

The object of the present invention is to overcome or substantially mitigate the aforesaid disadvantages.

According to a first aspect of the present invention there is provided a machine for mixing materials comprising a container with an inlet through which the materials to be mixed can be introduced into the container and in which is located a substantially upright auger coupled to a drive mechanism capable of rotating the auger to transport material upwardly within the container, and characterised in that a sleeve is located around the auger to define a first chamber within the container in which the auger is located and in that a second chamber is formed in the container, which second chamber communicates with the first chamber above the auger and can receive material transported upwardly by the auger.

Preferably, the sleeve defines an inner cavity within the container which comprises the first chamber and an outer cavity between the sleeve and the container which comprises the second chamber.

Preferably, the outer cavity also communicates with the inner cavity below the auger so that material introduced into the container can be circulated through the inner and outer cavities by the rotating action of the auger and the force of gravity.

Preferably also, a plough is linked to the auger and projects into the lower part of the outer cavity so that as the auger is rotated the plough also rotates and directs material from the outer cavity into the inner cavity.

Preferably also, the container is provided with an outlet which is located below the auger. The outlet can be provided with a valve or with a perforated plate through which mixed material can be extruded by reversing the direction of rotation of the auger to drive the material downwardly and out of the container.

Preferably also, grinding beads are located within the inner cavity, which communicates with the outer cavity above and below the auger via perforated plates or grids through which the materials to be mixed can pass but the grinding beads cannot.

Preferably also, the sleeve is perforated to permit the passage therethrough of at least one of the materials to be mixed.

According to a second aspect of the present invention there is provided a machine for separating aggregates or liquid/solid mixtures comprising a container with an inlet through which the materials to be separated can be introduced into the container and in which is located a substantially upright auger coupled to a drive mechanism capable of rotating the auger to transport the materials upwardly within the container, and characterised in that a sleeve is located around and above the auger to define an inner cavity within the container in which the auger is located and an outer cavity between the sleeve and the container, which outer cavity communicates with the inner cavity via perforations or apertures in the sleeve or in a perforated plate or grid closing the sleeve at the top, through which perforations or apertures only one constituent of the mixture can pass so that said one constituent is separated out from the mixture and is received by the outer cavity as the materials are transported upwardly by the auger.

Preferably, the container defines a a first outlet which communicates with the lower part of the outer cavity and a second outlet which communicates with the lower part of the inner cavity.

Preferably also, the inlet can feed the materials to be separated into the base of the container at the bottom of the auger.

The present invention will now be described by way of example with reference to the accompanying drawings in which: Fig. 1 is a schematic cross-sectional view of a mixing machine in accordance with the first aspect of the invention; Fig. 2 is a front elevation of a mixing machine similar to that shown in Fig. 1 but incorporating modifications; Fig. 2A is an enlarged view of part of the machine shown in Fig. 2; Fig. 3 is a plan view of the machine shown in Fig. 2; and Fig. 4 is a schematic cross-sectional view of a separating machine in accordance with the second aspect of the invention.

The mixing machines shown in Figs. 1 and 2 each comprise an upright cylindrical container 1 in which is axially located an auger 2 formed by a spiral vane 3 attached to a shaft 4. The shaft 4 is coupled to a drive mechanism 5 which is located above the container 1 and is capable of rotating the auger 2 to transport material upwardly within the container 1. The auger 2 is surrounded by a cylindrical sleeve 6 for most of its length and a cylindrical gap is left between the outer spiral edge 7 of the vane 3 and the sleeve 6. The sleeve 6 is supported within the container 1 by means of tie bars (not shown) by which it is attached to the container 1.

It can be seen in Figs. 1 and 2 that the sleeve 6 separates the interior space of the container 1 into two chambers comprising an inner cavity 8 in which the auger 2 is located and an outer cavity 9 defined by the sleeve 6 and the inner surface of the container 1. The cavities 8 and 9 communicate with one another both above and below the top and bottom of the sleeve 6 respectively. The bottom part 10 of the container 1 enclosing the lowest part of the auger 2 is funnel shaped so that material falling in the outer cavity 9 is directed into the inner cavity 8.

Materials to be mixed can be introduced into the container 1 in a variety of ways. For example, as shown in Fig, 1. a hopper 11 located at the base of the container 1 can be used to feed the materials into the funnel shaped bottom part 10 so that they fall on to the lowest part of the auger 2. Alternatively, the materials can be dropped into the top of either the outer or the inner cavities 8 and 9 from a hopper 12 located above or at the top the container 1. Dependent on the properties of the materials themselves, it may be more appropriate to use a screw feeder 13 to or a pipe inlet 14, which can both be located either at the top or bottom of the container 1. In Fig, 3 is shown a plurality of inlets 15 located in a cover plate 16 for the the container 1.

The mixed materials can be tipped out of the container 1 but in a preferred embodiment they are discharged from the container 1 via a bottom outlet 17 as shown in Fig. 2. The outlet 17 can be provided with a valve or a hinged plate or door so that the machine can operate as a batch mixer. However, in a modification, the outlet can be located centrally onf the container 1 and closed by a perforated plate 18 through which mixed materials can be extruded by reversing the direction of rotation of the auger 2 to drive the material downwardly and out of the container 1. Such an arrabngement is shown in Fig. 1.

In use, materials to be mixed are introduced into the container 1 using one of the various inlets as described above. The auger 2 is rotated by the drive mechanism 5 so that it tends to mix the materials in the inner cavity and transports them upwardly. It has been found that the action of the auger 2 on the materials in the cavity 8 not only causes them to rotate but also to tumble towards the edge 7 of the vane 3, which assists with the mixing process. When the materials reach the top of the auger 2 they are forced over the top of the sleeve 6 into the outer cavity 9 where they fall under gravity and are fed back to the bottom of the auger 2 assisted by the funnel shaped bottom part 10 of the container 1.

If one of the materials to be mixed is a viscous liquid or a sticky solid material, the auger 2 can be provided with a plough 19 (Fig. 2), which projects into the lower part of the outer cavity 9 below the sleeve 6 so that as the auger 2 is rotated the plough 19 also rotates and directs material from the outer cavity 9 into the inner cavity 8. In this case, the bottom part of the container 1 does not need to be funnel shaped and is preferably flat so that it is evenly swept by the plough.

The auger arrangement can also incorporate means to break up lumps of material if appropriate. For example, at the level of the top rim of the sleeve 6 the auger could be provided with a disc with depending fingers or teeth which can act on the material as it leaves the inner cavity 8.

Sometimes a smearing action is required to break down sticky materials and improve the mixing process. TO this end a spring-loaded pressure plate could be located at the top rim of the sleeve 6 so that material passing over the rim is smeared between the rim and the plate.

Alternatively, but fulfilling the same purpose a hinged plate with a variable weight dependent on the viscous properties of the the materials to be mixed could be located at the top rim of the sleeve 6.

Often, it is necessary to mix small quantities of dry materials which swell when water or other liquids are added to them, the wetted swollen mixture also requiring mixing. If only small quantities of material are loaded into the machine, it is advantageous to assist their passage through the sleeve 6 by castellating its top rim as shown in Fig. 2A. The castellations 20 can be simply square or rectangular in shape, or trapeziform as shown in Fig. 2A, which have the advantage of being self-relieving.

Alternatively, small quantities of mix can be assisted through the sleeve 6 by perforation of the upper part of the sleeve so that the material can escape without having to travel the whole length of the sleeve.

The machine can also be used to grind materials as it mixes. This is particularly useful for mixing paints where the pigment is a ground particulate. In this modification, grinding beads are located within the inner cavity 8, which is closed off from the outer cavity 9 above and below the auger by perforated plates or grids which are attached to the top and bottom edges of the sleeve 6. The holes in the plates or grids are arranged so that the materials to be mixed can pass through but the grinding beads cannot. In this way as the materials are conveyed upwardly by the auger 2 the grinding beads act on the solid materials to break them down to produce a finer mixture.Alternatively or in addition, assuming the inner cavity 8 is closed off from the bottom cavity 9 at the top by a plate and at the bottom by the sleeve 6 itself, the sleeve 6 can be perforated to permit the passage of the materials to be mixed but not the grinding beads.

The machine as described above can also be used for separating aggregates with particles or granules of different sizes and liquid/solid mixtures such as slurries.

To this end, as shown in Fig. 4, the machine comprises the container 1, auger 2 and sleeve 6 to define the inner and outer cavities 8 and 9 as previously described but in this case the inner and outer cavities do not communicate at the base of the auger 2; the outer cavity 9 is closed off by a plate 21 near the bottom of the container 1 and the top of the sleeve 6 is also closed off. However, either the sleeve 6 is perforated or the sleeve 6 is closed by a perforated plate or grid 22 so that only one constituent of the mixture can pass either through the perforations of the sleeve 6 or the plate or through the apertures of the grid from the inner cavity 8 into the outer cavity 9.With some materials, it may be appropriate for the sleeve 6 not to be perforated so that material overflowing from the inner cavity 8 into the outer cavity 9 through the perforated plate or gird 22 cannot be returned to the inner cavity 8 under any circumstances. An outlet 23 is provided in the container 1 at the bottom of the outer cavity 9 in which the separated out constituent of the mixture collects.

In this machine, the mixture to be separated is introduced to the bottom of the inner cavity 8 via a hopper 24. As the outer cavity 9 is closed off at its lower end, the material from the hopper 24 can only enter the inner cavity 8. Other means of introducing material to the machine can, however, be used as is suitable for the material in question.

It will be appreciated that in use the material introduced into the inner cavity 8 is carried upwards by the auger 2. However, the perforated plate or grid 22 will only allow liquid or material small enough to pass through its perforations or apertures to overflow into the outer cavity 9 and thence to be discharged via the outlet 23 in the cavity 9. Hence, solid material or the larger sized pieces of an aggregate material are retained in the inner cavity 8. When the inner cavity 8 is full or a batch of material has been processed by the machine, the contents of the inner cavity 8 can be discharged from the machine via a valve-controlled bottom outlet 25. Dependent on the material therein, the direction or rotation of the auger 2 can be reversed so that it drives out the contents of the cavity 8 through the outlet 25 if it is not free-flowing.

As previously described, this material can be extruded whilst being discharged from the machine if required As previously mentioned both the mixing machine and the separating machine are suitable for use in batch processing. One of the advantages of the mixing machine in this respect is that virtually the whole of the volume of the container 1 can be used for a batch which is a significantly greater batch capacity than that which can be accommodated by similarly sized containers of conventional mixing machines. This is because the arrangement of the auger and the inner and outer cavities ensures that all material passes through the mixing action of the auger.

However, it will be appreciated that the mixing machine could be used as part of a continuous process and that several machines could be linked together in a bank so that material cascades from one machine to another. In this arrangement, apart from the last machine in the range, each machine would be arranged so that instead of returning material to the base of its own auger the outer cavity would communicate with the lower part of the inner cavity of the next machine and become a feeder therefor.

In an alternative arrangement of the mixing machine, the first and second chambers are positioned side-by-side within the container and communicate with one another both above and below the auger in the first container so that material introduced into the container can be circulated around the first and second chambers by the rotating action of the auger and the force of gravity. Preferably, the second chamber houses a second auger or other means coupled to a second drive mechanism capable of rotating the second auger or other means to assist in the transportation of the material downwardly within the second chamber. If augers are used in the two chambers, the machine is particularly suitable for mixing clays and similar materials which are not free-flowing so that transportation around the machine and therefore homogeneous mixing is ensured.Alternatively, the second chamber could house a series of rotating discs, blades or other harrowing means which can be used for breaking up lumps in materials such as foundry sands whilst still assisting in the transportation of these materials back to the base of the auger in the first chamber. A high speed auger with attached blades or the like could also be used for this purpose in the second chamber.

The machine according to the invention has several advantages over conventional mixing or separating machines. It is suitable for processing most types of materials, for example liquids, powder, granules, fibres and the like. Material does not have to be elevated to the top of the machine as it can be fed in from the base obviating any requirement for an elevator or vertical conveyor. The design of the mixing machine ensures that a homogeneous mix is obtained quickly as all material passes through the mixing action after just one pass of the machine; this is a significant improvement on existing machines where pockets of material can be left unmixed. In turn, this means that delicate materials are not exposed to excessive agitation and are less likely to be damaged although in any event the mixing action of the machine is always gentle. The speed of the auger can be arranged to be suitable for the quickness of mixing required and the fragility of the materials being processed.

The machine is of simple construction and is, therefore, easy to maintain. The power required is also low for the quantity of material processed as the drive mechanism has only to cope with the weight of material which rests on the vane of the auger and any forces caused by the viscous properties of the material itself.

In addition to mixing or separating materials, the machine can also be provided, where required, with ancillary equipment to cool or heat the materials whilst they are being processed.

Claims (18)

1. A machine for mixing materials comprising a container with an inlet through which the materials to be mixed can be introduced into the container and in which is located a substantially upright auger coupled to a drive mechanism capable of rotating the auger to transport material upwardly within the container, and characterised in that a sleeve is located around the auger to define a first chamber within the container in which the auger is located and in that a second chamber is formed in the container, which second chamber communicates with the first chamber above the auger and can receive material transported upwardly by the auger.

2. A machine as claimed in Claim 1, wherein the sleeve defines an inner cavity within the container which comprises the first chamber and an outer cavity between the sleeve and the container which comprises the second chamber.

3. A machine as claimed in Claim 2, wherein the outer cavity also communicates with the inner cavity below the auger so that material introduced into the container can be circulated through the inner and outer cavities by the rotating action of the auger and the force of gravity.

4. A machine as claimed in any one of Claims 1 to 3, wherein, the inlet can feed material into the base of the container at the bottom of the auger.

5. A machine as claimed in any one of Claims 1 to 3, wherein the inlet is located at the top of the container.

6. A machine as claimed in any one of Claims 1 to 5, wherein the lower part of the container enclosing the lowest part of the auger is funnel shaped so that material falling in the outer cavity is directed into the inner cavity.

7. A machine as claimed in any one of Claims 1 to 6, wherein a plough is linked to the auger and projects into the lower part of the outer cavity so that as the auger is rotated the plough also rotates and directs material from the outer cavity into the inner cavity.

8. A machine as claimed in any one of Claims 1 to 7, wherein the container is provided with an outlet which is located below the auger and closable by a valve.

9. A machine as claimed in any one of Claims 1 to 7, wherein the container is provided with an outlet covered by a perforated plate through which mixed material can be extruded by reversing the direction of rotation of the auger to drive the material downwardly and out of the container.

10. A machine as claimed in any one of Claims 1 to 9, wherein grinding beads are located within the inner cavity, which communicates with the outer cavity above and below the auger via perforated plates or grids through which the materials to be mixed can pass but the grinding beads cannot.

11. A machine as claimed in any one of Claims 1 to 10, wherein the sleeve is perforated to permit the passage therethrough of at least one of the materials to be mixed.

12. A machine as claimed in Claim 1, wherein the first and second chambers are positioned side-by-side and communicate with one another both above and below the auger so that material introduced into the container can be circulated around the first and second chambers by the rotating action of the auger and the force of gravity.

13. A machine as claimed in Claim 12, wherein the second chamber houses a second auger or other means coupled to a second drive mechanism capable of rotating the second auger or other means to assist in the transportation of the material downwardly within the second chamber.

14. A machine for separating aggregates or liquid/solid mixtures comprising a container with an inlet through which the materials to be separated can be introduced into the container and in which is located a substantially upright auger coupled to a drive mechanism capable of rotating the auger to transport the materials upwardly within the container, and characterised in that a sleeve is located around and above the auger to define an inner cavity within the container in which the auger is located and an outer cavity between the sleeve and the container, which outer cavity communicates with the inner cavity via perforations or apertures in the sleeve or in a perforated plate or grid closing the sleeve at the top, through which perforations or apertures only one constituent of the mixture can pass so that said one constituent is separated out from the mixture and is received by the outer cavity as the materials are transported upwardly by the auger.

15. A machine as claimed in Claim 14, wherein the container defines a a first outlet which communicates with the lower part of the outer cavity and a second outlet which communicates with the lower part of the inner cavity.

16. A machine as claimed in Claim 14 or Claim 15, wherein the inlet can feed the materials to be separated into the base of the container at the bottom of the auger.

17. A machine for mixing materials substantially as described herein with reference to any of Figs. 1, 2, 2A and 3 of the accompanying drawings.

18. A machine for for separating aggregates or liquid/solid mixtures substantially as described herein with reference to Fig. 4 of the accompanying drawings.