FIELD OF THE INVENTION

The present invention relates to improvements in loading and

discharging concrete mixers, particularly, but not exclusively, to skid-mounted or vehicle-mounted concrete mixers; and to associated methods.

BACKGROUND TO THE INVENTION

Construction sites often have stationary concrete mixers for storing concrete prior to the concrete being utilised, such as by piling machines. These stationary concrete mixers generally have a rotatable drum mounted to a frame known as a skid. Typically, the inlet to the skid mounted mixer is an inlet cone which has a reduced diameter mouth into which concrete can be poured from a loading hopper.

Generally, the skid-mounted concrete mixer is filled by a truck-mounted concrete mixer which brings prepared concrete to the construction site. The truck-mounted mixer usually has a discharge chute which is used to transfer concrete from the truck to the skid-mounted concrete mixer drum via the loading hopper and the inlet cone.

The design of conventional skid mounted mixers is such that the inlet to the loading hopper for filling the skid mounted mixer is normally higher than the discharge chute of the truck-mounted mixer. To transfer concrete from the truck-mounted mixer it is usually necessary to elevate the truck to align the loading hopper and the discharge chute. Typically, a ramp is used to elevate the discharge chute of the truck. However, as the discharge chute is usually mounted to the rear of the truck, the truck has to reverse up the ramp. Once aligned the transfer of concrete can take place into the drum via the truck- mounted mixer discharge chute and the mixer loading hopper.

Often it is not desirable to have a ramp on a construction site or to have a truck reversing up a ramp: for example, from a health and safety perspective, or with a view to time or space efficiencies.

Conventional skid mixers are commonly designed to be tilted from a substantially horizontal configuration to an inclined configuration. A substantially horizontal configuration assists in reducing the height required of the truck's discharge chute to transfer concrete under gravity into the mixer. The inclined configuration assists in providing sufficient height to discharge the concrete from the mixer into a receiving device, such as a concrete pump. Typically, this tilting is achieved by the provision of hydraulic rams. Such a tilting arrangement can have drawbacks, such as added weight or expense of the tilting

components; and/or inefficiencies. Previously it has been attempted to reduce the tilting required of a mixer, such as in the present Applicant's international patent application PCT/GB/2008/002314, the contents of which are

incorporated by reference.

SUMMARY OF THE INVENTION

According to an aspect of the invention, there is provided a concrete mixer, the mixer comprising: a rotatable vessel configured to mix concrete upon rotation of the vessel; and

a rotatable inlet cone configured to transport concrete material and/or concrete making materials, into the vessel through a vessel axial opening upon rotation of the inlet cone;

wherein the inlet cone is received at least partially through within the vessel via the vessel axial opening, wherein the arrangement of the vessel axial opening and the inlet cone is configured to prevent fluid communication of concrete from the vessel into the inlet cone in a loading configuration and in a discharging configuration.

Configuring the mixer to prevent fluid communication of concrete from the vessel into the inlet cone may enable the mixer to comprise disparate loading and unloading portions, such as enabling the mixer to comprise a lower loading portion than a discharging portion (than where fluid communication of concrete from the vessel into the inlet cone is enabled).

For the avoidance of doubt, the term "inlet cone" is used as it is a term in the art. To fall within the scope of the present invention, the inlet cone does not have to be purely conical.

Configuring the mixer to prevent fluid communication of concrete from the vessel into the inlet cone may enable the inlet cone to comprise attributes not possible with a conventional inlet cone that is in constant fluid

communication with a vessel.

For example, where the inlet cone comprises a cone vane and the vessel may comprise a vessel vane and wherein the cone vane comprises a pitch and/or a height and/or a taper substantially independent of the pitch, height and taper of the vessel vane i.e. the respective vessel and cone vanes may comprise a pitch and/or a height and/or a taper substantially independent of the pitch and/or a height and/or a taper of the other vane.

The inlet cone and/or the vessel may comprise a helical vane/s.

The mixer may be configured to exclusively load the vessel through the inlet cone. The mixer may be configured to prevent discharge from the vessel through the inlet cone. The mixer may be configured to prevent discharge from the vessel through the inlet cone in a loading and/or a discharging

configuration/s.

The loading configuration is where material is loaded into the vessel through the axial opening in the vessel via the inlet cone, wherein a discharge end of the inlet cone defines a first diameter and wherein the axial opening of the vessel defines a second diameter and wherein the second diameter is greater than the first diameter.

The mixer may be configured to load material into the vessel at a first diameter through the axial opening in the vessel and to discharge concrete through the axial opening at a second diameter, wherein the second diameter is greater than the first diameter.

A discharge gap may be defined between the axial opening of the vessel and an external surface of the inlet cone, wherein the discharge gap is sufficient to prevent discharge material contacting the external surface of the inlet cone in the discharge configuration, wherein concrete material is discharged from the vessel via the discharge gap. The vessel may include an internal mixing element and wherein the discharge gap is defined between the mixing element and the external surface of the inlet cone.

The mixing element may be a directional mixing paddle or a vane. The mixer may comprise a separation between the mixing element and the cone, such as a vertical gap.

The discharge gap may define an outlet between the vessel and the external surface of the inlet cone, wherein the outlet permits discharging concrete material from the vessel and wherein the outlet is a substantially annular opening defined by the vessel axial opening and an external surface of the inlet cone at the axial opening.

The inlet cone may be attached to the vessel and may be fixed relative to the vessel. For example, the inlet cone may be mounted on a support within the vessel. The support may comprise one or more substantially radial member/s.

Alternatively, the inlet cone may be movable relative to the vessel relative to the axial opening of the vessel, wherein the inlet cone extends into the vessel in a loading configuration and the inlet cone is at least partially removed from the vessel in one or more of a mixing, storage and discharge configuration.

The mixer may be configured to discharge concrete from the outlet by rotation of the vessel, such as a rotation in a first direction (e.g. a clockwise direction). The inlet cone may be rotatable with the vessel. The mixer may be configured to load material into the vessel by rotation of the inlet cone in a second direction (e.g. a counter-clockwise direction). The inlet cone may be concentric with the vessel. The inlet cone may be coaxial with the vessel.

The inlet cone may be attached to the vessel such that the inlet cone rotates with the vessel.

The inlet cone may be retrofitted to the vessel.

The inlet cone may be adapted to be retrofitted to a conventional mixer drum and/or a conventional inlet cone, such as concentrically within a conventional inlet cone, spanning the conventional inlet cone's mouth. Such an arrangement may be advantageous because the mounting of the inlet cone to a conventional inlet cone further distances, in use, the user from the drum of the truck mixer.

The inlet cone may extend into the vessel. The inlet cone may extend axially into the vessel beyond the mixer discharge outlet. The inlet cone may extend axially out from the vessel beyond the mixer discharge outlet.

The inlet cone may comprise a charging mouth configured to receive concrete material, from a chute or hopper, for transporting into the vessel and an exit port configured to discharge concrete material into the vessel.

The charging mouth may comprise a greater diameter than the exit port. The charging mouth may define the vessel/mixer loading portion.

The outlet may comprise the discharging portion. The loading portion may be positioned at a lower height than the discharging portion, such as in a loading (or charge) and/or a storage and/or a discharge configuration. The mixer may comprise a separation between the vessel and the cone exit port, such as a vertical gap. The mixer may comprise a separation between the vessel mixing element and the cone exit port, such as a vertical gap.

The inlet cone may comprise a tapered portion, the tapered portion tapering inwardly towards the vessel. The tapered portion may enable a loading device to load material into the cone at a lower height. The inlet cone may comprise a substantially cylindrical portion. The substantially cylindrical portion may assist in axially displacing the concrete material.

The inlet cone may comprise a flared portion external to the vessel axial opening. Outside/external to the vessel the inlet cone is substantially

unrestricted in its dimensions, as such a flared portion may provide for an increased taper that may allow for a greater increase in diameter over a shorter axial distance. A greater increase in diameter over a shorter axial distance may enable a lower loading portion for a similar total length; or a reduced total length for a similar height loading portion; or a combination of reduced loading portion height and reduced total axial length.

The mixer may be configured to be loaded and discharged with the vessel at the same inclination. The mixer may be configured to be loaded and discharged without raising or lowering the vessel, such as tilting the vessel.

Enabling the mixer be loaded, such as fully-loaded, and discharged, such as fully discharged, without raising or lowering the vessel may eliminate a need for components, such as lifting components (e.g. a ram). Eliminating

components may reduce costs and/or weight; and/or may enable additional or alternative features, such as enabling discharge into a concrete receiving device, such as a concrete pump, adjacent, such as directly vertically below, the outlet. Enabling discharge into a receiving device adjacent the outlet may permit a reduced height loss during discharge, such as otherwise may be associated with discharge via a long chute.

A pump may be positioned below the vessel, such as directly below the vessel axial opening in a discharging configuration. Accordingly, concrete may be discharged directly from the vessel into the pump. Discharging the concrete directly into the pump may enable the dispensation of additional concrete discharge elements, such as a discharge hopper and/or a discharge chute and/or an ear chute. The mixer may include the pump. For example, where the mixer is a skid mounted mixer the pump may be mounted to the skid. The pump may be fixed relative to the vessel. For example, the pump may be mounted below the vessel, such as directly below the discharge gap/outlet in a

discharging configuration.

The mixer may comprise a skid. The skid may be configured to be track- mounted.

The mixer may be configured to be exclusively loaded through the inlet cone.

The inlet cone may be configured to exclusively load the vessel. The inlet cone may be configured to prevent discharge from the mixer through the inlet cone. The inlet cone may comprise a charging mouth lip, such as an internal flange or internal ring. The charging mouth lip may provide a continuous loading height at the charging mouth throughout rotation of the inlet cone during loading. Providing a continuous loading height at the charging mouth throughout rotation of the inlet cone during loading may enable material to be loaded into the inlet cone from a loading device (e.g. a chute) with a reduced axial insertion into the inlet cone of the loading device (compared to an inlet cone with a discontinuous loading height at the charging mouth, such as an inlet cone with a helical vane terminating at an open charging mouth). A reduced axial insertion of a loading device into the inlet cone may reduce a risk of damage to the inlet cone, such as damage to a cone vane; and/or may assist in viewing a loading operation. The charging mouth ring may comprise a substantially similar height to a cone vane adjacent the charging mouth lip.

A further aspect of the invention provides a rotatable inlet cone for a concrete mixer according to the first aspect, wherein the inlet cone is configured to transport concrete material into a concrete mixer vessel through a vessel axial opening by rotation of the inlet cone;

wherein the inlet cone is configured to prevent fluid communication of concrete from the vessel into the inlet cone in a loading configuration and a discharge configuration.

The inlet cone may comprise an exit port for discharging material into a concrete mixer vessel.

The exit port may comprise a lesser diameter than a mixer vessel axial opening. Providing an exit port of lesser diameter than a mixer vessel axial opening may enable the inlet cone to be inserted into the vessel beyond the axial opening; and may enable the exit port to be separated from the vessel, such as to be positioned above concrete in the vessel. This arran The inlet cone may be configured to attach to the concrete mixer, such as to attach to be rotatable with the vessel. The inlet cone may be configured to be retrofitted to the concrete mixer.

A method of mixing concrete, may comprise loading material, such as concrete, into a concrete mixer inlet cone;

rotating the inlet cone to transport the material into a concrete mixer vessel, such as a drum, through a vessel axial opening;

preventing fluid communication of concrete from the vessel into the inlet cone in a loading configuration and in a discharging configuration.

The method may further comprise rotating the vessel, such as counter- rotating the vessel, to discharge the concrete through the axial opening.

The method may further comprise exclusively loading the vessel through the inlet cone. The method may further comprise preventing discharge from the vessel through the inlet cone.

The method may further comprise loading material into the vessel at a first diameter through the axial opening in the vessel and to discharge concrete through the axial opening at a second diameter, wherein the second diameter is greater than the first diameter. The first diameter may be defined by the inlet cone within the vessel axial opening. The second diameter may be defined by the axial opening.

Other aspects of the present invention relate to the use of the mixer and/or inlet cone according to any one of the aspects in loading and/or unloading and/or mixing and/or storing concrete. It should be appreciated that features recited as optional with respect to one aspect should be considered applicable with respect to any other aspect, without the need to explicitly and unnecessarily list those various combinations and permutations here. For example, features of the inlet cone of the first aspect may be combined with features of the inlet cone of the further aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a schematic side view of a concrete mixer in accordance with an embodiment of the invention;

Figure 2 is a schematic perspective partial view of a concrete mixer in accordance with an embodiment of the invention;

Figure 3 is a schematic side partial view of the concrete mixer of Figure

2;

Figure 4 is a schematic side partial view of the concrete mixer of Figure 2 in a loading configuration;

Figure 5 is a schematic side partial view of the concrete mixer of Figure 2 in an unloading configuration; and

Figure 6 is a schematic perspective partial view of a concrete mixer in accordance with an embodiment of the invention. DETAILED DESCRIPTION OF THE DRAWINGS

Reference is first made to Figure 1 in which a skid-mounted mixer is shown, generally indicated by reference numeral 10. The mixer 10 comprises a drum 12 rotatably mounted to a skid 14, the skid 14 sitting on the ground 5. The drum 12 has an axial opening 13 through which concrete can be loaded and unloaded. The mixer 10 further comprises a rotatable inlet cone 16 and a loading hopper 26. The inlet cone 16 is configured to transport concrete into the drum 12 through the vessel axial opening 13 by rotation of the inlet cone 16. The mixer 10 is configured to prevent fluid communication of concrete from the drum 12 into the inlet cone 16.

The inlet cone 16 has an exit port 18 configured to discharge concrete into the drum 12, and a mouth 20 adapted to receive the loading hopper 26. The inlet cone 16 has an internal surface 24 which defines a radially

decreasing, or converging, taper from the mouth 20 to the exit port 18. The inlet cone 15 has an external surface 25 which is separated from an internal surface 27 of the drum by a gap 29 at the axial opening 13. The gap 29 defines an outlet 31 between the drum 12 and the inlet cone 16.

Also shown on Figure 1 is a truck mounted mixer 30. The truck mounted mixer 30 has a mixer drum 22 and a discharge chute 28. The discharge chute 28 pours concrete from a truck mounted mixer drum 22 into the loading hopper 26. In turn, under the effects of gravity, the concrete transfers from the loading hopper 26 to the inlet cone 16. In turn, the concrete transfers through the inlet cone 16 from the mouth 20 to the exit port 18 under a screw effect during rotation of the inlet cone 16; and transfers to the drum 12 under gravity from the exit port 18.

As can be seen from Figure 1 , the converging inlet cone 16 permits the concrete to be transferred from the truck 30 to the mixer 10 without the need to elevate the truck 30 with respect to the mixer 10. The disparate mouth 20 of the inlet cone 16 for loading concrete and the outlet 31 for discharging concrete permits the concrete to be transferred from the truck 30 to the mixer 10 without the need to tilt the drum 12.

Referring to Figures 2 to 5, there is shown a mixer 1 10. The mixer 1 10 shown in Figures 2 to 5 is generally similar to that shown in Figure 1 , and as such like features share like reference numerals, incremented by 100.

Accordingly, the mixer 1 10 comprises a drum 1 12 and an inlet cone 1 16, with an outlet 131 defined between the cone 1 16 and the drum 1 12.

The cone 1 16 comprises helical vanes 132 for transporting concrete through the inlet cone 1 16 under a screw effect during rotation of the cone 1 16. The drum comprises helical vanes 134 for mixing and transporting concrete in the drum 1 12 during rotation of the drum 1 12. The cone 1 16 shown is attached within the drum 1 12 such that the cone 1 16 rotates with the drum 1 12 about a longitudinal axis 136 of the mixer. Arrow A indicates where concrete is loaded into the mixer 1 10 at a loading portion of the mouth 120 of the inlet cone 1 16. The inlet cone 1 16 has a lip 138 for retaining concrete in the inlet cone 1 16 during loading. As can be seen in Figure 4, the lip 138 ensures that the mixer 1 10 can be filled with a minimal axial insertion of a loading hopper into the inlet cone 1 16, as exemplified by the termination of the arrow A. Accordingly the inlet cone 1 16 can be axially shorter than without the lip 138.

Although not shown in Figures 2 to 5, the mixer further comprises a loading hopper for loading concrete into the inlet cone 1 16. The loading hopper is fixed such that it does not rotate with the inlet cone 1 16.

The mixer 1 10 further comprises a concrete pump 140 positioned directly below the outlet 131 such that concrete can be discharged directly from the drum 1 12 into the concrete pump.

Figure 4 shows the distribution of concrete in the mixer 1 10 during loading, as indicated by the cross-hatched areas. Concrete is loaded into the inlet cone 1 16 at a loading portion as indicated by arrow A in Figure 4. The rotation of the drum 1 12 and the attached inlet cone 1 16 about the longitudinal axis 136 in a counter-clockwise direction indicated by arrow C forces the concrete through the inlet cone 1 16 by a screw effect of the vanes 132. When the concrete reaches the exit port 1 18 of the inlet cone 1 16 the concrete is discharged into the drum 1 12 as indicated by arrow D. The vanes 134 in the drum 1 12 transport, mix and retain the concrete within the drum 1 12 during rotation of the drum 1 12 in the counter-clockwise direction.

Figure 5 shows the distribution of concrete in the mixer 1 10 during discharging, as indicated by the cross-hatched areas. The rotation of the drum 1 12 and the attached inlet cone 1 16 about the longitudinal axis 136 is reversed to a clockwise direction indicated by arrow C. The vanes 134 in the drum 1 12 force the concrete towards the axial opening 1 13 under a screw effect. The concrete passes between the internal surface 127 of the drum 1 12 and the external surface 125 of the inlet cone 1 16, through the gap 129, out through the outlet 131 to fall under gravity into the concrete pump 140 positioned directly below. In the embodiment shown, the gap 129 is sufficient relative to the vanes 134 to ensure that concrete does not contact the external surface 125 of the inlet cone 1 16.

As can be seen in Figures 4 and 5, the disparate mouth 120 and the outlet 131 permit concrete to be loaded and/or discharged from the drum 1 12 without raising or lowering the drum 1 12. The loading configuration of Figure 4 is generally the same as the unloading configuration of Figure 5, with the direction of rotation reversed.

Referring to Figure 6, there is shown a mixer 210. The mixer 210 shown in Figure 6 is generally similar to that shown in Figures 2 to 5, and as such like features share like reference numerals, incremented by 100. Accordingly, the mixer 210 comprises a drum 212 and an inlet cone 216, with an outlet 231 defined between the cone 216 and the drum 212.

The inlet cone 212 comprises a flared portion 250. The flared portion 250 is positioned outside the drum 212 and is unrestricted in its dimensions by the drum 212. Accordingly, the flared portion 250 has an increased taper compared to a tapered portion 252 adjacent the drum's 212 axial opening 213. The increased taper allows for a greater increase in diameter of the inlet cone 216 over a shorter axial distance. The greater increase in diameter over a shorter axial distance enables a relatively lower loading portion as indicated by arrow A in Figure 6. Accordingly, the drum 212 can be more inclined in the embodiment of Figure 6, whilst maintaining similar loading heights as indicated by arrow A. The greater inclination of the drum 212 allows an increased capacity and an increased height from the ground of the outlet 231 , such as to allow more space for a concrete pump 240 directly beneath the outlet 231 .

It should be understood that the embodiments described herein are merely exemplary and that various modifications may be made thereto without departing from the scope of the invention. For example, although shown here in a substantially horizontal orientation, it will be appreciated that it may be appropriate to incline the drum, such as to increase a volumetric capacity of the mixer. Although shown here for use with concrete, a mixer may be suitable for use with another aggregate/s, such as grit (e.g. to salt or grit roads). Although shown here with cylindrical portions and tapered portions that taper inwardly towards the vessel, it will be appreciated that other embodiments of inlet cones may include outwardly tapered portions. For example, inside the vessel an outwardly tapered portion may assist in discharging concrete from the inlet cone.