WO2001034358A1

WO2001034358A1 - A mixer

Info

Publication number: WO2001034358A1
Application number: PCT/SG2000/000042
Authority: WO
Inventors: Eng Soon Goh; Eng Hock Goh
Original assignee: Tan, Hoe, Beng
Priority date: 1999-11-12
Filing date: 2000-03-25
Publication date: 2001-05-17
Also published as: WO2001034357A1; AU3690200A; AU7698400A

Abstract

A mixer for mixing fluid or particulate materials is disclosed. The mixer comprises a mixing drum, within which the material can be mixed, said mixing drum including one or more openings through which material to be mixed can be charged into the drum and through which the mixed material can be discharged from the drum, characterised in that the mixer includes an outer structure of dimensions which enable the mixer to be stackable, detachable and transportable. A number of the mixers can be stacked one on top of the other so as to minimise the floor space or ground area taken up by the mixers. If the dimensions of the outer structure are to conform to the conventional containers, it will enable the mixers to be stackable with these conventional containers, thus resulting in more efficient and economic logistic handling of such mixers when delivered by international freight companies.

Description

A MIXER

The present invention relates to a mixer. In particular, the present invention relates to a mixer of a type that is suitable for mixing fluid and particulate materials such as dry flowable particulate matter mixtures, slurries of particular matters in liquids, and liquids. Examples of these materials include dry/wet concrete mixtures, mortars, screeds, cement, sand, dry/wet animal feed, chemicals, coffee mix, beans and soft drink mixtures.

A number of designs for mixers suitable for mixing particulate and fluid materials are known. One of the best known mixers is the ready mix concrete mixing truck having a cylindrical or tapering drum mounted on top . This mixing truck is used to transport "ready mixed concrete" in the form produced in a batching plant and to discharge the ready mix concrete at the customer's location.

In the ready mix concrete industry, when concrete is required to be delivered to a specific location, the ready mix concrete is produced at the batching plant and charged into the ready mix concrete mixing truck. The mixing truck is driven to the delivery destination at which point the ready mix concrete is discharged from the mixing truck.

A number of constraints are placed on the suppliers of ready mix concrete as a result of the requirement that the ready mix concrete be produced and distributed from the batching plant. Firstly, if a great volume of ready mix concrete is ordered by one or; more parties at the same time, the batching plant production capacity will limit the ability of the ready mix concrete company to deliver the quantities of concrete ordered to the required destinations. In addition, the nature of wet ready mix concrete does not allow pre-production in readiness for such times of high activity since the concrete may set and harden in the time between production and the placement of an order for the concrete. There are also times when concrete cannot be delivered to customers requiring the concrete outside normal opening hours for the concrete producer.

In an attempt to address the difficulties associated with the production and delivery of wet ready mix concrete, a dry mix concrete concept has been introduced into the industry. However, ineffective storage problems still exist because the truck- type mixers in the prior art do not enable effective storage of the dry mix therein. The only method of storage of dry mix concrete being delivered by such trucks is by lining the trucks up one by one. This is not however a feasible option for the efficient storage of the dry mix concrete due to high capital investment of the prime movers and inefficient usage of land.

Accordingly, it is an object of the present invention to provide an improved mixer design which alleviates the problems associated with the storage of products and/or semi-products prior to use.

According to the present invention there is provided a mixer for mixing fluid or particulate materials, said mixer including a mixing drum within which the material can be mixed, said mixing drum including one or more openings through which the ^'material to be mixed can be charged into the drum and through which mixed material can be discharged from the drum, characterised in that the mixer includes an outer structure of dimensions which enable the mixer to be stackable, detachable and transportable .

As will be understood, by providing a mixer with an outer structure having dimensions which is stackable, detachable and transportable, it becomes possible to store materials prior to use in the mixers one on top of the other so as to minimise the floor space or ground area taken up by the mixers containing the particulate or fluid material. This multi-functionality of the mixer of the present invention is not available with the mixers of the prior art. The mixer of the present invention enables mixing of the materials, stacking, storage and transportation in the one mixer.

A further advantage of the mixer is that the mixer enables prefabricated or premixed materials to be prepared before use and delivered to the required destination well in advance of the time it is required to be used. This can therefore alleviate the problems of batching plant production- limits at busy order times by producing prefabricated or premixed materials which can be stored around the clock. This also avoids the risk of road traffic delaying delivery and therefore delaying the concrete-laying operation for "just-in-time" concrete delivery operations. Moreover, since the device of the present invention is capable of mixing contents inside the drum, this can eliminate the need for a batching plant where pre-mixing of ingredients occurs.

The outer structure may be of any suitable configuration provided that the outer structure is dimensioned so as they are stackable, detachable and transportable. For example, the outer structure may be open-sided or close-sided. Preferably, the outer structure comprises an open-sided framework. This may be formed from any suitable materials such as for one example only, steel .

Conventional containers which are used for transporting materials by road, rail or sea often come in a series of standard sizes. It is preferred that the outer structure be of dimensions which enable the mixer to be stacked with conventional containers of these standard sizes .

When the outer structure comprises a framework, preferably the framework includes outer frame components which define the outer boundaries of the mixer, and inner frame components which support the mixing drum. As is explained in further detail below, it may be the case that the inner frame components support the mixing drums in such a way as to enable the drum to be rotated.

More preferably, an upper side of the outer frame component defines a substantially horizontal surface upon which a lower side of another outer frame can be stackable with it.

Preferably, the mixing drum is rotatable.

Preferably, the interior of the mixing drum is provided with a mixing blade so as to enable mixing of the contents of the drum. The mixing blade may be of any suitable type. For example, the mixing blade may be of a type that is capable of rotating relative to the mixing drum. Alternatively, if the drum is rotatable, the mixing blade may be of a type that is mounted to the drum in such a way that the mixing blade rotates with the drum. A further alternative involves the provision of more than one blade in the mixing drum, including a first blade which rotates relative to the drum and the second blade which is mounted to the drum in such a way that the second blade rotates with the drum.

The drum may be of any suitable shape, including cylindrical drums, tapering drums and irregular shaped drums. Essentially the shape of the drum merely must be one which enables the contents of the drum to be mixed by any suitable means such as, for example, by rotation or by mixing the contents with a rotating blade. The drum will usually have a central lateral axis.

The or each opening to the drum through which material can be charged into and discharged from the drum may be of any suitable configuration and in any suitable location of the drum. For example, one opening only may be provided in an axial end region of the drum, this single opening enabling material to be charged and discharged therethrough. Alternatively separate openings may be provided for charging material into the drum, and the other for discharging material from the drum. For one example only, a first charging opening may be provided in a circumferential side region of the drum, and a second charging/discharging opening may be provided in an axial end region of the drum.

It is preferred that each opening be provided with a cover to prevent material escaping from the mixing drum, and/or to prevent foreign material from entering into the mixing drum.

If the opening is provided with a cover which can be placed over the opening, the cover could be of a "submarine" type configuration having a hinge on one side and a latching mechanism, or could be of a "man-hole" configuration without a hinge, or any appropriate configuration . If each of the openings to the drum is provided with an air-tight cover, the contents in the drum may be able to be stored for very long periods of time without affecting the quality of the contents. This also makes it possible for storable semi and pre-mixed materials to be delivered over long distances, by either road transport, rail or sea.

According to the present invention there is also provided a method of modifying a mixer including a mixing drum which is capable of mixing contents of the drum, said mixing drum including one or more openings through which material to be mixed can be charged into the drum and through which mixed material can be discharged from the drum, so that the mixer is capable of being stackable, detachable and transportable, the method including forming an outer structure for the mixer said outer structure being of dimensions which enable the mixer to be stackable, detachable and transportable including the same outer structure .

The present invention will now be described in further detail with reference to the following figures which illustrate various preferred embodiments of the invention, and in which:

Figure 1 is a perspective view of two mixers of two preferred embodiments of the invention stacked one on ^• another;

Figure 2 is a schematic illustration of seven mixers of the present invention stacked one on the other in two columns;

Figure 3 is a schematic side illustration of a mixer of one preferred embodiment of the invention;

Figure 4 is a schematic side illustration of a mixer of a second preferred embodiment of the invention;

Figure 5 is a schematic side illustration of a mixer of a third preferred embodiment of the invention;

Figure 6 is a schematic side illustration of the mounting means for the mixer illustrated in Figure 3;

Figure 7 is a schematic side illustration of the mounting means for the mixer illustrated in Figure 4;

Figure 8 is a schematic end-on illustration showing mixer rotation directions ;

Figure 9 is one possible internal configuration for the mixer illustrated in Figure 3;

Figure 10 is one possible internal configuration for the mixer illustration in Figure 4;

Figure 11 is a second possible internal configuration for the mixer illustrated in Figure 3 ;

Figure 12 is a second possible internal configuration for the mixer illustrated in Figure 4;

Figure 13 is a third possible internal configuration for the mixer illustrated in Figure 3;

Figure 14 is a third possible internal , configuration for the mixer illustrated in Figure 4;

Figure 15 is a schematic side illustration of the mixer illustrated generally in Figure 4;

Figure 16 is a schematic side illustration of the mixer illustrated in Figure 4 being filled with material through side openings;

Figure 17 is a schematic side illustration of the mixer illustrated in Figure 4 being filled with material through an end opening;

Figure 18 is a schematic side illustration of the mixer illustrated in Figure 3 placed on a trailer;

Figure 19 is a schematic side illustration of the mixer illustrated in Figure 4 placed on a trailer;

Figure 20 is a schematic side illustration of two of the mixers illustrated in Figure 3 placed on the same trailer to be towed by a single truck or prime mover;

Figure 21 is a schematic side illustration of the mixer on a trailer illustrated in Figure 19 being delivered by a prime mover .

Figure 1 illustrates mixers of two alternative embodiments of the invention stacked one on another. Each of the mixers includes a mixing drum 1. The mixing drum of a first embodiment of the invention which is illustrated on top is of a tapered drum configuration and has a central lateral axis. The drum of the second embodiment of the invention which is underneath is generally cylindrical in shape with the axis of the drum extending laterally. Each of the mixers includes an axial end opening 2 and . a circumferential side opening (not illustrated in Figure 1) through which material to be mixed can be charged into the drum 1 and through which mixed material can be discharged from the drum 1. Specifically, fluid or particulate material can be charged into either of openings 2 and 5, and discharged from opening 2. The mixers of each embodiment of the invention also include an outer structure in the form of a framework having dimensions which enable the mixers to be stackable, detachable and transportable.

The framework of the two mixers illustrated in Figure 1 is open- sided and includes outer frame components 3a which define the outer boundaries of the mixer, and inner frame components 3b which support the mixing drum. The framework of the preferred embodiments illustrated is formed from steel, and essentially defines a square or rectangular box which encases the mixer. An upper side of the outer frame component 3a defines a substantially horizontal surface upon which a lower side of the outer frame component 3a of a like mixer can be stacked. Nevertheless, it will be understood to persons skilled in the art of the invention that many other configurations of the outer framework would be possible. Such alternative outer structures or outer frameworks may include closed- sided structures 7. Of course, in the case of a closed- sided outer structure, openings will be provided in the side of the outer-structure to enable access to the or each opening in the mixing drum. In Figure 2 there is illustrated a series of alternative forms of mixer of the present invention having either open- sided (as indicated by the broken lines) or closed-sided (as indicated by solid lines) outer structures.

As illustrated in Figure 2, the mixers of the preferred embodiments of the invention may be layered in a stacked a number of mixers high. The mixers illustrated in Figure 2 each include end openings 2 at the radially outer ends of the mixing drums 1. The mixers having cylindrical drums as indicated by the number 4 also include side openings 5 in a radial side region of the drum 1. Each of the cylindrical drums illustrated in Figure 2 includes two side openings 5.

Each of the mixers of the preferred embodiments of the invention illustrated include a filling and discharge system 6 adjacent to the end opening 2 of the mixing drum 1. This filling and discharge system consists of an entry funnel and a discharge chute.

The mixer of the first preferred embodiment of the invention illustrated in Figure 3 includes a mixing drum 1 which is tapered to each axial end, and a single opening 2 through which material to be mixed can be charged into the drum 1 and discharged from the drum 1.

Openings throughout the drawings which are shaded indicate that the opening has been covered by a cover . Unshaded ovals for openings indicate that the cover is not placed over the opening, such that the opening is in an open condition. For example, in Figure 4, one of the side openings 5 is in an open condition, and the second of the side openings 5 is in a closed condition with the cover placed over the opening. The end opening 2 is also covered.

As is illustrated in Figure 5, the mixer according to a third preferred embodiment of the invention is mounted within a closed-sided container 7 and is adapted to be moveable between a first position in which the mixer is located within the confines of the container, and a second position in which the mixing drum is located at least partially outside the confines of the closed-sided container 7. Movement between the first and second positions is in the direction indicated by arrow A. Any suitable mechanism known to persons skilled in the art of the invention for moving the mixing drum between the first and second positions may be utilised. A locking mechanism is also included to prevent unnecessary movement of the mixing drum.

In mixers of the preferred embodiments of the invention illustrated, the mixing drum is rotatable. The taper mixer of the first preferred embodiment of the present invention is mounted to support structures 8 in such a way as to enable the mixing drum to be rotated or revolved to effect mixing of the contents. The mixer of the second preferred embodiment of the invention illustrated in Figure 7 is mounted within the framework 3 by means of a series of roller rings 9 which encircle the cylindrical drum and a series of corresponding rollers 10. As is illustrated in Figure 8 the mixing drum 1 can be rotated in either a clockwise C or an anticlockwise B direction .

The mixing drums 1 according to the preferred embodiments of the invention illustrated include at least one mixing blade. Figures 9 and 10 illustrate one possible internal configuration for the mixers of the first and second preferred embodiments of the invention, which involve the provision of a "shell blade" 11. The shell blade 11 is mounted to the mixing drum 1 in such a way that the shell blade 11 rotates with the drum. As the drum is rotated in one direction, material within the central cavity of the drum is caused to be churned by the shell blade. If the drum is rotated in the opposite direction, material will be fed up the blade and out of the end opening 2 of the drum 1.

According to a second alternative embodiment illustrated in Figures 11 and 12, the mixing blade is in the form of a "shaft blade" 12 which is mounted to a shaft of the mixing drum 1 so that the blade can be rotated relative to the mixing drum. Specifically, the relative rotation of the shaft blade with respect to the mixing drum is achieved either by rotating the rotating drum in one direction (for example in direction B) whilst rotating the shaft blade in an opposite direction (C) , or alternatively by keeping the mixing drum 1 stationery and rotating the shaft blade 12 only. Rotation of the blade in an opposite direction will result in material being fed up the central blade and out of the end opening 2 of the drum 1.

A third alternative for the provision of a mixing blade involves the provision of both shell 11 and shaft 12 blades within the mixing drum.

As will be understood to persons skilled in the art of the invention, the various mounting and support arrangements and the drive mechanisms by which rotation of the drums and/or blade (s) are achieved are flexible and an appropriate mechanism can be selected for any particular application. For example, rotation of the mixers can be achieved by using hydraulic, pneumatic, mechanical, electrical drives and/or any suitable combination. The drive mechanism can be by virtue of a direct or indirect drive mechanism or any suitable combination thereof.

As illustrated with reference to Figure 15, the location of the mixing drum within the confines of the outer structure of the mixer contributes to the stability of the mixer as a whole during the filling, mixing, transportation and discharge processes. This is due to the fact that the centre of gravity of the mixer is located close to the base of the container which itself fς>πns a stable surface.

As illustrated in Figures 18 to 21, the mixer can be placed on a trailer 15 (either singly or in twos) for delivery to a site by a vehicle 14 such as a prime mover. Two mixers can be delivered either by stacking one on top of the other on a single trailer (not illustrated) or in a row as illustrated in Figure 20.

The operation of the mixer will now be described with reference to the following examples which relate to the mixing of components for forming ready mix concrete.

It is to be noted that the overall efficiency of any industry that involves large volumes in terms of storage, mixing, transportation and discharge of a product (such as the ready mix concrete industry) will be greatly affected by logistic operations.

The ready mix concrete industry is characterised by large volume, "just in time" production and peak plant capacity. Therefore, an increase in the overall operation efficiency must take into account each of these characteristics .

Ready mix concrete is made from a mixture of materials including, principally, cement, sand, granite and water. Once all of these components and other necessary components are mixed, the ready mix concrete will begin to harden or bond. Accordingly, if it is desired to provide a mixture which can be stored for a prolonged period of time without hardening or bonding, the cement and water cannot be stored together in the mixer. Instead, a mixture of the sand and granite, or the sand, water and granite, or the sand, granite and cement may be stored in the mixer on- site, and when ready mix concrete is required, the final components (being the cement or the water, respectively) are then added to the mixer to be mixed with the other components in the mixer and discharged. According to a first example, granite and sand in the correct ratios are filled into the mixer via the side openings 5 (as illustrated in Figure 16) , or via the end opening 2 (as illustrated in Figure 17) . Thereafter, the covers are closed over the respective openings and the mixer is sent to store. The mixer may be stored at the location where the granite and sand are charged into the mixer, or may be transported to a location where ready mix concrete has been pre-ordered ready for use on site at any chosen time. The mixer may be stacked on top of other mixers at the delivery location. Accordingly, the mixer containing the granite and sand in the correct ratios can be stored efficiently.

When ready mix concrete is required to be laid, water and cement can be charged into the- mixer through either the side opening (s) 5 or the end opening 2. Mixing of the contents of the mixer is achieved by any suitable means, for example, by way of the relative rotation between the mixing drum and the blade (s) .

In an alternative version of the same example, the sand and granite is pre-mixed prior to charging in the required quantity into the mixer. Thereafter, again, the filling covers are closed and the mixer is delivered to the desired location for storage. When ready mix concrete is required, cement and water are charged into the mixer and mixing of the stored contents with the newly charged contents is achieved by a few rotations of the drum. Thereafter the concrete is ready for use.

According to a second example, all components of the ready mix concrete except cement are charged into the mixer. Thereafter the filling covers are closed and the mixer is sent to storage at the desired location. When ready mix concrete is required, the cement is charged into the mixer the contents of the mixer are mixed by the method described above.

According to a third example, all of the dry components of the ready mix concrete are charged in the correct ratios in to the mixer. These components in the mixer can be sent to storage for a prolonged period. At the time when the ready mix concrete is required, water is charged into the mixer followed by mixing rotation of the mixing drum prior to the discharging of the mixed concrete. Again, the dry materials can be charged in the correct ratios either individually or together following pre- mixing .

Of course, the mixer of the present invention can be used in accordance with the standard protocol in which all ready mix concrete components are mixed together and delivered to the required destination ready for immediate use. Accordingly, the mixer of the present invention is versatile since it can be used both for immediate mixture and delivery or for storage purposes prior to mixture and use .

As will be understood to persons skilled in the art of the invention, if the openings in the mixing drum are provided with air-tight covers or alternatively, if the outer structure provides an air-tight encasement of the enclosed mixing drum, materials that are at risk of deteriorating on exposure to oxygen, moisture or the outside elements can be stored for extended periods of time without risk of degradation.

After the ready mix concrete or other contents of the mixer have been discharged, the mixer can be cleaned by feeding water into the mixer, rotating the mixer a number of times with the water inside to rinse the interior of the mixer and thereafter discharging the wash water from the mixer. Any appropriate means of water supply can be used for this purpose. A water tank with or without a water pump or booster can be also integrated into a truck or other vehicle which is used to transport the mixer, for one example. After water cleaning of the mixing drum, the interior of the mixer can be left to dry either in a stationary position or on the journey back to the ready mix concrete plant. Alternatively, an air jet could be used to blow air into the mixer to speed up the drying process. Air injected into the drum may be at ambient temperature or may be preheated.

The mixer of the present invention can be formed by retro- fitting a mixer having a mixing drum which is capable of mixing contents of the mixing drum, the mixing drum including an opening through which the material to be mixed can be charged into the drum in through which mixed material can be discharged from the drum so as to be capable of being stackable, detachable and transportable. This retro- fitting operation involves forming an outer structure for the mixer. The required framework for the mixer can be constructed around the mixing drum in such a way that the mixing drum is mounted within this outer structure.

Many modifications may be made to the present invention without departing from the spirit and scope thereof. A number of these modifications have been discussed above in relation to the description of the preferred embodiment of the invention. However, it is to be understood that the modifications described above are not exhaustive.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS :

1. A mixer for mixing fluid or particulate materials, said mixer comprising a mixing drum, within which the material can be mixed, said mixing drum including one or more openings through which material to be mixed can be charged into the drum and through which the mixed material can be discharged from the drum, characterised in that the mixer includes an outer structure of dimensions which enable the mixer to be stackable, detachable and transportable.

2. The mixer as claimed in claim 1 wherein the outer structure comprises a framework.

3. The mixer as claimed in claim 2 wherein the outer structure is open-sided.

4. The mixer as claimed in claim 3 wherein the framework includes outer frame components which define the outer boundaries of the mixer, and inner frame components which support the mixing drum.

5. The mixer as claimed in claim 2 wherein the framework is closed-sided.

6. The mixer as claimed in any one of claims 2 to 5 wherein an upper side of the framework defines a substantially horizontal surface upon which a lower side of the outer framework is able to be stackable with it.

7. The mixer as claimed in any of the claims 1 to 6 wherein the outer structure, besides being capable of enabling the mixer to be detachable and transportable, can also be in dimensions that are capable of enabling the mixer to be stackable with any container, such as the conventional 20-feet and 40-feet containers.

8. The mixer as claimed in any one of claims 1 to 7 wherein the mixing drum is rotatable.

9. The mixer as claimed in any one of claims 1 to 8 wherein the interior of the mixing drum is provided with a mixing blade for mixing of the contents of the drum.

10. The mixer as claimed in claim 9 wherein the mixing blade is capable of rotating relative to the mixing drum.

11. The mixer as claimed in claim 9 wherein the mixing drum is rotatable, and mixing blade is mounted to the drum in such a way that the mixing blade can rotate with the drum.

12. The mixer as claimed in claim 9 wherein the mixing drum includes more than one blade, including a first blade which can rotate relative to the drum, and a second blade which is mounted to the drum in such a way that the second blade rotates with the drum.

13. The mixer as claimed in any one of claims 1 to 12 wherein the or each opening in the mixing drum is provided with a cover to prevent material escaping from the mixing drum and/or to prevent foreign material from entering into the mixing drum.

14. A method of modifying a mixer including a mixing drum which is capable of mixing contents of the drum, said drum including one or more openings through which material to be mixed can be charged into the drum and through which the mixed material can be discharged from the drum, so that the mixer is capable of being stackable, detachable and transportable, the method comprising forming an outer structure for the mixer, said outer structure besides being capable of enabling the mixer to be detachable and transportable can also be in dimensions that enable the mixer to be stackable with any container, such as the conventional 20-feet and 40-feet containers.

15. A mixer substantially as herein described with reference to the accompanying drawings.