Patent Description:
Bulk material handling apparatus such as silos, hoppers, chutes, drums, conveyors, and so on, invariably suffer from accumulation of the bulk material being handled that progressively reduces their effectiveness. This is particularly the case with bulk materials which tend to agglomerate under certain conditions. One example of such materials includes cementitious materials which may become adhesive to the apparatus under certain conditions of moisture or atmospheric humidity. In the context of the present invention, the term 'accumulate' and its derivative terms are intended to encompass material agglomeration and other adhesive materials and processes, including lamination of material to apparatus surfaces.

With accumulation of material on apparatus surfaces, both short-term and long-term efficiency is compromised, with the flow of material along or through the apparatus being restricted or stopped completely, and the capacity and throughput of the apparatus reduced. Additionally, accumulation causes increased stresses on walls and bearings of the apparatus as the mass of material increases, reducing the lifespan of the apparatus, increasing maintenance requirements, and can reduce energy efficiency.

Accumulation may be affected by the design of the apparatus, or by the properties of the bulk material being handled. Some bulk materials are heavily prone to adhesion and accumulation on surfaces and are difficult to handle. Therefore, suitable methods of cleaning are required.

Common methods of cleaning include vibrators, air cannons, aeration pads, and scrapers. These are effective, but often require a significant amount of energy, and may result in gradual damage to the device.

Rotary drums can be used for a variety of purposes, including rotary drying and cooling, granulation, cleaning, or coating and can be used to achieve many goals across numerous industries and for a wide range of materials, particularly bulk materials. Specific, but nonlimiting, example applications include agriculture (such as processing of manure, compost or NPK fertiliser), metallurgy (such as metal ore processing), minerals (such as limestone dust or mine tailings), pharmaceuticals (such as tablet coating), waste processing (for example, gas cleaning residues), manufactured aggregate production and food (such as sugar).

Rotary drums are versatile and reliable but may incur issues when handling more difficult bulk materials. Build-up can occur as material adheres to itself and to the wall of the drum. Scrapers acting on the interior of the drum are commonly employed, but the rotation of the drum may be adversely affected when the scraper comes into contact with a large, built-up mass of material. This may also affect the quality of the material being processed. Equally, wear upon the drum and the scraper itself may be an issue.

It is with these problems in mind that the present invention has been devised.

The document <CIT> discloses a material handling system in accordance with the preamble of claim <NUM>.

In its broadest sense, the present invention is defined by the material handling system of claim <NUM>, which provides a material handling system comprising a rigid frame and a moveable liner, wherein the frame includes at least one aperture having an area and wherein the system comprises an actuator system for applying a force to a surface of the liner in the area of the aperture.

In the context of the present invention, the term 'cleaning' is not limited to complete removal of material and includes reduction in the amount of material accumulated to the apparatus. In general, the invention concerns the transport and/or handling of a solid material. The solid material may be in the form of particles and/or aggregates (e.g. agglomerates formed from a mass of fragments or particles compacted together).

The invention also provides, in accordance with claim <NUM>, a method of handling and/or transporting a material with a material handling system as defined in claim <NUM>. The method comprises: (i) depositing the material onto a surface of a moveable liner and (ii) applying a force to a surface of the moveable liner to reduce or prevent accumulation (e.g. permanent accumulation) of the material on the surface of the moveable liner. The method may be performed with the material handling system of the invention.

Further aspects of the disclosure relate to a pellet and to a process for the preparation of one or more of the pellets.

The invention provides, in accordance with claim <NUM>, a process for the preparation of one or more pellets using a material handling system as defined in claim <NUM>. The process comprises: mixing fine particulates and a binder in a rotatable drum of a material handling system in accordance with the invention to form one or more pellets, wherein a force is applied to a surface of a moveable liner of the material handling system during the mixing of the fine particulates and the binder to reduce or prevent accumulation (e.g. permanent accumulation) thereof on the surface of the moveable liner.

Also provided by the disclosure is a pellet. The pellet is, for example, for use as a construction material (e.g. a construction aggregate). The pellet is obtained or is obtainable (e.g. directly obtained or obtainable) by the process of the invention. The pellet comprises, or consists essentially of, fine particulates and a binder in the form of an aggregate. The pellet is preferably a spheroidal pellet or a nodular pellet.

The invention manufactures pellets of enhanced quality due having a constantly clean drum surface that ensures efficient flow or tumbling of the agglomerating mass which is not disrupted by accumulation. The resulting pellets are therefore well formed and mechanically resilient.

Typically, the movable liner is a flexible liner, optionally an elastomeric or rubber liner. Alternatively, the moveable liner comprises a rigid or resilient member. The rigid or resilient member may be flexibly or elastically mounted to the frame.

In accordance with the invention, the liner provides a continuous surface for transporting and/handling the material. The continuous surface does not include one of more apertures, e.g. for particles and/or agglomerates of the material to pass through the liner. The purpose of the liner is to transport the material through the system. The liner is not for sorting or sieving particles and/or agglomerates of the material based on their size.

It is generally preferred that the liner is not, or does not comprise, a mesh.

Preferably, the actuator system applies a force to the liner. The force is for reducing or preventing the accumulation (e.g. permanent accumulation) of the material on a surface of the liner. For example, the force can dislodge and/or remove material that has adhered to the surface of the liner.

Typically, the force applied to the liner is substantially perpendicular to a surface of the liner.

The liner may have an internal or first surface for supporting and/or transporting the material. The liner may also have an outer or second surface. The outer or second surface may be on the opposite side of the liner to the internal or first surface of the liner.

It is preferred that the actuator system applies a force at an outer or second surface of the liner, such as in an area of an aperture of the frame.

The actuator system may apply a force to the liner externally of the rigid frame.

The or each aperture of the frame provides an area where the actuator system can apply a force to a surface of the liner.

Typically, the force applied to the liner is a tapping force. The tapping force may be applied to the liner at a regular frequency or intermittently, preferably the tapping force is applied to the liner at a regular frequency. The frequency may be synchronized with the rotation speed of the frame. The tapping force is for reducing or preventing the accumulation (e.g. permanent accumulation) of the material on a surface of the liner.

The actuator system may comprise a rotatable shaft having at least one actuator arm mounted e.g. radially thereto. It is preferred that the rotatable shaft has a plurality of actuator arms, where each actuator arm is mounted radially to the rotatable shaft.

In general, the or each actuator arm is arranged to bear against the liner, particularly the moveable liner. The or each actuator arm may be arranged to bear against an outer or second surface of the liner.

The system may further comprise a prime mover for rotating the rotatable shaft. The prime mover may be an electric, pneumatic or hydraulic motor, which may further optionally comprise at least one of a belt drive, chain drive and gearing assembly.

Typically, the actuator system comprises at least one actuator arm pivotally mounted adjacent an area of an aperture. When the actuator system comprises a plurality of actuator arms, then the plurality or a subset of the plurality of actuator arms may be pivotally mounted adjacent the area of an aperture.

The or each actuator arm may comprise a distally-mounted wheel or roller.

Typically, at least one of the actuator arms or each actuator arm may be cranked or bent. The or each actuator arm is attached at a right angle to the rotatable shaft.

In accordance with the invention, the material handling system includes an inclination adjustment system for adjusting the angle. The inclination adjustment system is for adjusting the angle of the rigid frame and/or the moveable liner to the ground.

The actuator system may comprise at least one linear actuator adapted to bear against the moveable liner. The actuator system may comprise a plurality of linear actuators, wherein each actuator is adapted to bear against the moveable liner.

Advantageously, the system further comprises load cells for weighing material in or passing through the system. The load cells can be used to help determine the weight of material in or flowing through the system.

In a first embodiment, the rigid frame is in the form of a rotatable drum.

Typically, the rotatable drum has a longitudinal axis of rotation. The axis of rotation may be inclined to the horizontal up to an angle of about <NUM>°; such as at an angle of from <NUM>° (e.g. greater than <NUM>°, such as <NUM>°) to about <NUM>°; preferably up to about <NUM>°, such as from about <NUM>° (e.g. greater than <NUM>°, such as <NUM>°) to about <NUM>°.

In a second embodiment, the rigid frame is in the form of a hopper or chute. For example, the rigid frame may be a frame supporting a conveyor belt.

In the pellet and the process for the preparation of one or more of the pellets, the fine particulates may be particulates of waste (e.g. inert waste or mineral waste) or particulates of minerals. For example, the fine particulates may be mineral wastes from quarrying and mining, processed mineral-derived products such cement and lime, and industrial residues such as combustion or energy recovery processes, metallurgical processes, and processed mineral products.

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

The apparatus of the present invention may, itself, may be static, such as a chute or hopper, having an ancillary source of deformation; or may be dynamic, such as a rotatable drum or conveyor and include an active source inducing deformation e.g., a rotating vessel with weighted rollers acting upon the deformable liner. Examples will be discussed below.

<FIG> shows, schematically, a rotatable drum <NUM> of the type which is typically used in material handling processes, to tumble aggregates or other materials with compositions for coating the materials. Conventional drums commonly suffer from accumulation of material on the inner surfaces of the drum, especially in respect of materials which are adhesive or develop adhesive properties under the conditions under which the drum operates, such as humidity. The present invention seeks to address this problem by providing a drum <NUM> having a rigid frame <NUM> forming a supporting structure for a flexible liner <NUM>.

In general, frame <NUM> includes at least one aperture <NUM> such that a force or forces F can be applied to an outer surface of flexible liner <NUM> through aperture <NUM> from an actuator mechanism (not shown in <FIG>) externally of the drum <NUM>. Deformation of the liner <NUM> in reaction to the applied force F causes at least a portion of any material which has adhered to the inner surface of the liner <NUM> to become detached from the liner.

The flexible liner <NUM> is suitably formed of rubber. The liner <NUM> is fixed to the frame <NUM> to prevent slipping or axial or lateral movement. The apertures <NUM> in the frame <NUM> expose the liner <NUM>. A force F is then applied to the exposed areas of the liner to induce flexure.

The drum illustrated in <FIG> is suitably of the type of rotating drum <NUM> used for the purposes of pelletising, granulation, drying or cooling.

Frame <NUM> is typically mounted on wheels or rollers which are directly or indirectly driven by a motor to cause rotation of the frame and thus any material retained within the liner <NUM>. Material is fed into an inlet end of the drum <NUM>, and transits through the drum by the action of gravity, exiting the drum <NUM> at the opposite, outlet end.

<FIG> shows, in side and front views, an embodiment of the apparatus of the present invention in the form of a hopper <NUM>, of the type which may be used for the storage or collection of material, or a chute, such as may be used for transfer of bulk material <NUM> from one location to another.

Generally, the hopper has a rigid frame <NUM> having apertures <NUM> and is lined by a flexible liner <NUM>. Liner <NUM> may be formed as a single component or with an individual sheet associated with each surface of the hopper. A force F may be applied to the liner <NUM> through the apertures <NUM> in frame <NUM>. Walls of the hopper or chute may be planar, as shown, or any suitable shape.

In modifications to the use of a flexible liner as described above, the apparatus of the present invention may use a rigid liner, flexibly mounted to frame <NUM>, <NUM>, for example by means of a flexible gusset or bellows-type arrangement or other connection means. In such embodiments, the liner is caused to move with respect to its rest configuration by the actuator mechanism rather than by flexing of the liner.

Deformation or movement of the liner <NUM>,<NUM> may be achieved by any suitable means, as will be within the routine skill, knowledge, and experience of the skilled person, and may include the use of springs or pneumatic, hydraulic, or electrically-powered actuators.

<FIG> illustrates, partially, an example of a chute or hopper having a flexible liner <NUM>. The chute is fitted with an exemplary actuator <NUM>.

As a general feature of the invention, actuator <NUM> may have a shaft <NUM> driven by means of a prime mover, such as an electric or hydraulic motor <NUM> and, optionally, an intervening gear, chain, or belt drive <NUM>. Shaft <NUM> has a plurality of massagers <NUM> mounted thereto such that, as the shaft <NUM> rotates, massagers <NUM> also rotated and, in doing so, press against an outer surface of liner <NUM>, correspondingly causing inner surface of the liner to deform and eject any material adhering to the inner surface.

Each massager <NUM> may be in the form of an elongate actuator arm <NUM> mounted at a proximal end to the shaft <NUM> and provided with a wheel or roller <NUM> at its distal end (as shown by the embodiment in <FIG>). Rollers <NUM> act to reduce frictional wearing forces between the distal end of each actuator arm <NUM> and the liner <NUM> as the shaft rotates.

The chute may have a curved profile, as, for example, shown in the embodiment of <FIG>. Each actuator arm <NUM> may be cranked such that the distal end of each actuator arm is substantially perpendicular with the adjacent most surface of the liner. In the context of the actuator arms <NUM> of <FIG>, this has the effect that the axis of rotation of each roller <NUM> is parallel with the adjacent most surface of the liner <NUM>.

A plurality (e.g. four are shown in the embodiment) cranked massagers <NUM> is provided. The cranked massagers <NUM> are arranged alternately radially spaced <NUM>° about shaft <NUM> such that, with rotation of the shaft, a first pair of massagers <NUM> simultaneously engage or beat against liner <NUM>. As the shaft continues to rotate about its longitudinal axis, a second pair of massagers come into contact with liner <NUM>. Alternative arrangements are equally suitable and may be selected by the skilled person having regard to the size of the apparatus, flexibility of the liner and the nature of the bulk material.

<FIG> shows a system incorporating a number of different self-cleaning elements of the present invention.

As a general feature of the invention, the system may include a feed conveyor <NUM> comprising a belt <NUM> (e.g. driven between a rotatable drum <NUM>). Belt <NUM> is thereby arranged to have an upper belt portion <NUM>, presenting a belt surface <NUM> for transporting a material <NUM> in the direction of output drum <NUM> whereupon the material <NUM> falls from the belt <NUM> into a hopper or chute <NUM> as belt <NUM> turns over output drum <NUM> and returns, as a lower belt portion <NUM>, towards the first rotatable drum.

The system may include drive means, suitably in the form of a motor (not shown in <FIG>), to propel belt <NUM> over the drums.

As described above, bulk material <NUM> is ejected from the belt <NUM> into a chute <NUM>. Chute <NUM> is of the type shown in <FIG> and <FIG> and includes a flexible liner <NUM> within a frame <NUM> (not shown in detail). The chute <NUM> is provided with a series, as required, of pneumatic or hydraulic linear actuators <NUM>, or other actuators, acting against liner <NUM>.

The system further includes a rotatable drum system <NUM> of the type described above with respect to the embodiment of <FIG>.

In this example, the rotating drum <NUM> is mounted on four support wheels <NUM>, which are either driven directly or as shown, via a belt or chain system including a circumferential chain <NUM> driven by an electric or hydraulic motor <NUM>. The drum <NUM> has an axis of rotation which is arranged to be inclined to the horizontal by between <NUM>° and about <NUM>° to control a residence time for material within the drum <NUM>. The system may include an adjustment mechanism to allow for adjustment of the inclination angle in use. Agitator or tensioning arms <NUM> are pivotally mounted above drum <NUM> and each is fitted with a wheel or roller <NUM> to act upon the flexible liner <NUM>, as described above, to induce deflection. In this embodiment, arms <NUM> are mounted to a supporting frame <NUM> for the drum system <NUM> with a simple pivot or hinge mount. As drum <NUM> rotates, longitudinal ribs <NUM> pass under wheels <NUM> and lift each wheel <NUM> and associated arm <NUM>, as ribs <NUM> move away from the agitator arms, each arm and its associated wheel falls under gravity against liner <NUM>, thereby dislodging any material adhered to the inner surface of the liner.

Processed material <NUM> is ejected from drum system <NUM>.

In general, and by way of example, in an apparatus of the invention is for granulating materials (e.g. heavy bulk minerals), such as those with a loose bulk density of <NUM>-<NUM>/m<NUM>.

The drum may have a diameter of at least <NUM>, preferably at least <NUM>.

Typically, the length of the drum is at least <NUM>, preferably at least <NUM>, more preferably at least <NUM>.

In general, the liner is a sheet. Preferably, the sheet has a thickness of from <NUM> to <NUM>, more preferably <NUM> to <NUM> (e.g. about <NUM>). It is preferred that the sheet is a rubber sheet.

Each aperture typically has an area of about <NUM> to about <NUM><NUM>, preferably about <NUM> to about <NUM><NUM>.

For example, the drum may have a diameter of the order of <NUM> and a length of <NUM>. Each aperture may conveniently measures about <NUM> by <NUM> and the liner is suitably made from <NUM> thick rubber sheet.

Claim 1:
A material handling system (<NUM>) comprising a rigid frame (<NUM>) and a moveable liner (<NUM>), wherein the rigid frame (<NUM>) is in the form of a rotatable drum (<NUM>, <NUM>) and the moveable liner (<NUM>) is fixed to the frame (<NUM>) to prevent slipping, and the moveable liner (<NUM>) provides a continuous surface for transporting or handling a material, wherein the frame (<NUM>) includes at least one aperture (<NUM>) having an area and wherein the system comprises an actuator (<NUM>) system for applying a force to a surface of the liner in the area of the aperture, characterized in that the actuator system (<NUM>) comprises a rotatable shaft (<NUM>) having at least one actuator arm (<NUM>) mounted radially thereto, wherein the or each actuator arm (<NUM>, <NUM>) is arranged to bear against the moveable liner (<NUM>), and wherein the system includes an inclination adjustment system for adjusting an angle of the rigid frame (<NUM>) and/or the moveable liner (<NUM>) to the ground.