The invention relates to material discharge apparatus, generally having a tapering outlet hopper at its base closable by a closure or valve which is moved into the wider region of the hopper to allow discharge of flowable material. The material is usually a powder, pellets or like flowabie material.

In the transport, storage and general handling of flowabie material such as powder, particulate material, granules and the like, it is nowadays usual for such materials to be held in bins, containers, hoppers, solos, or intermediate bulk containers ( I.B. C's). Such containers have a filling inlet and a discharge outlet T he outlet is often of hopper configuration, and is usually obturated by a closure device which is substantially conical or frusto-conieah The cone in the obturating position rests on the inner (in use) surface of the outlet hopper. At a discharge or transfer station, the closure device is raised from the hopper outlet by suitable means, such as a bellows device marketed raider the registered trade mark MATCON®, to open an araiular discharge opening between the hopper outlet and the closure device through which a desired amount of the flowabie material can pass to other stations for use.

GB 1415721 describes a material discharge apparatus in which a plurality of actuating cylinders are fixed rigidly to the outside surface of a material discharge chute around the periphery thereof, and a closure device within the chute is attached indirectly by a number of mounting posts and resilient springs, to the movable parts of the actuating cylinders which are also outside the chute.

EP 0045163 relates to a material discharge apparatus comprising a material receiving chute, a flow control member above the chute and an actuating member, the apparatus comprising vibrating means fixed to the flow control member to impart thereto a linear oscillatory motion in a direction parallel to the direction of movement of the flow control member by the actuating device. EPO 380255 describes a material handling system, for example an intermediate hulk container system, which is used to handle ilowable material such as powders, pellets, slurries and the like.

An object of the present invention is to provide material discharge apparatus to improve the flow of material from an outlet of the container, It has been found that when using some cohesive sticky powders, the local compaction caused at the edge of known valves results in inter-particle adhesion or fusion. The present invention seeks to mitigate problems such as these.

According to a first aspect of the invention there is provided a material discharge apparatus comprising a material receiving chute having a longitudinal axis; a valve above the chute movable between raised and lowered positions to control flow of material into the material receiving chute tfom a hulk store thereof above the latter: an actuating device having a movable part for moving the valve between raised and lowered positions; wherein the movable part of the actuating device is disposed so as to move along a single central axis aligned with the valve; and wherein the valve comprises a top surface and one or more sidewall that is substantially parallel with the longitudinal axis of the chute.

Advantageously, the use of a valve having one or more sidewall that is substantially parallel with the longitudinal axis of the chute facilitates the discharge of large volumes of products such as sugar without the problems associated with known valves. This is in contrast with known valves wherein compression of products such as sugar by the valve edge may cause the product to aggregate and block the outlet of the valve, reducing and/ or preventing the flow of product from the container. Preferably, the said one or more sidewall is disposed, in use, above the seal. Preferably, the said one or more sidewall is disposed, in use, within the material to he discharged when the valve is closed. Advantageously, the provision of apparatus having one or more sidewall disposed above the seal and/ or disposed within the material to be discharged when the valve is closed prevents a zone of compacted powder forming adjacent to the outlet.

It is preferred that the one or more sidewall comprises a substantially vertical wall, in use. which may act as a flow control member to control the flow of material into the material receiving chute from a bulk store above the latter. Where the valve has a single sidewall, it is preferred that the wail is cylindrical, it is further preferred that the valve includes a conical bottom (in use) wall that is adapted to cooperate with the lifting cone of a discharge device. It is further preferred that the top, in rise, surface of the valve comprises means to prevent build up of material there upon. The top surface may be hemispherical, conical or pyramidal or any similar shape so as to assist in preventing compaction of material above the valve. Preferably, the apparatus further comprises means for adjusting the height of the valve.

It is preferred that the height adjusting means is a control device which can be varied to determine tbe operation of the actuating device. Preferably, the one or more vertical sidewali of the valve has a height that may be different for use with different powders. Preferably, the one or more vertical sidewall of the valve has an optimal height that is determined based on the type of powder that is used. In one embodiment the one or more sidewall has a height that is approximately the same as the height of the chute. Preferably, the one or more sidewall has a height that is substantially equal to or greater than tbe lift height of the valve. Preferably, the height of the one or more sidewall of the valve is determined to an optimal height such that it prevents a zone of compacted powder forming adjacent to the outlet. Advantageously, the provision of a vertical sidewall having a short height allows for production of the valve at lower cost compared with valves having a sidewall of longer length, in addition, the provision of a valve having a. vertical sidewall of shorter length reduces the weight of the valve and improves the volume of power that may be accommodated when compared with a valve having a longer length vertical sidewall.

In one embodiment, the one or more vertical sidewall of the valve has a variable height. Preferably, the material receiving chute is of tapering wall form and is rigidly mounted on the bottom of a bin or silo and communicating with the interior thereof

Preferably, the actuating device is a bellows or a fluidic cylinder whose movable part is a ram. The actuating device may be positioned below or above the valve, as is known in the art.

According to a second aspect of the invention, there is provided a kit for conversion of a valve for use in material discharge apparatus comprising a material receiving chute having a longitudinal axis; a valve above the chute movable between raised and lowered positions to control flow of material into the material receiving chute from a bulk store thereof above the latter; an actuating device having a movable part for moving the valve between raised and lowered positions; wherein the movable part of the aclnating device is disposed so as to move along a single central axis aligned with the valve; wherein the kit comprises a valve cover for fitment to the valve, the valve cover comprising one or more sidewall that is substantially parallel with the longitudinal axis of the chnte.

It is preferred that the valve cover comprises a substantially hollow body adapted to fit over or upon the existing valve. It is further preferred that the valve cover comprises one or more substantially hollow cylinder sized to accommodate therein a cone valve. in one embodiment, the kit may comprise a series of different sizes of rings, wherein the number and/ or size of one or more rings is selected and placed adjacent to the valve, depending on the height of the valve that is required. Advantageously, the provision of one or more rings results in a valve that has a variable height.

According to a third aspect of the invention, there is provided a method for discharging flowable material from material discharge apparatus, comprising the nse of apparatus as defined hereinabove. According to a fourth aspect of the invention, there is provided a method of converting the valve of material discharge apparatus for nse with flowable sticky particulates, comprising providing a valve cover adapted to fit over the existing valve, the valve cover comprising one or more sidewall that is substantially parallel with the longitudinal axis of a discharge ehute of the apparatus.

It is preferred that the method includes the step of providing a substantially cylindrical valve cover sized to fit over a cone valve of the apparatus.

The invention will further be described by way of example and with reference to the following illustrated in the following figures, in which:

Figure 1 is a side view of material discharge apparatus in accordance with the invention;

Figure 2a is a front perspective view of a prior art valve: Figure 2b is a side schematic view of a prior art valve and material discharge apparatus, wherein the valve is in the lowered, obturating position; Figure 2c is a side schematic view of a prior art valve and material discharge apparatus, wherein the valve is in the raised position;

Figure 3 is a front view of a valve in accordance with the invention; Figure 4a is a side view of a valve in accordance with one embodiment of the invention;

Figure 4b is a side schematic view of a valve and material discharge apparatus according to one embodiment of the invention, wherein the valve is in the lowered, obturating position; Fignre 4c is a side schematic view of a valve and material discharge apparatus according to one embodiment of the invention, wherein the valve is in the raised position;

Figure 5 is a top plan view of a valve in accordance with the invention; Figure 6a is a side schematic view of a valve and material discharge apparatus according to one embodiment of the invention, wherein the valve is in the lowered, obturating position; and

Fignre 6b is a side schematic view of a valve and material discharge apparatus according to one embodiment of the invention, wherein the valve is in the raised position,

Referring to Figure 1 , there is shown a system 1 for handling ilowable material, comprising a discharge station 2, a transportable station or I.B.C. 3 for holding and transporting ilowable material such as powder 4 and discharging it at the discharge station 2, and seal means 5 of the two stations 2 and 3.

The discharge station 2 comprises a fixed chute or hopper 6 mounted on a framework 7 which extends to either side thereof to provide a support for fork channel guides or feet 8 of the transportable station 3 which is in the form of a bin or I.B.C having a throat 9 leading to an outlet 10, the throat/outlet 9, 10 being sized to fit into the upper (as viewed) tree edge 1 1 of the chute 6,

The outlet 10 is normally obturated by a captive cylindrical valve 12 which is shown in the obturating positl on to the right of Fig. 1 , and in a raised or open position to the left in Fig. 1 to create an amiulus between a free edge or rim 13 thereof and the adjacent wad of the throat 9, flowable material 4 in the open position of the valve 12 being enabled to flow ont of the station 3 through the annular passage to the chute 6 aid thence on to further processing. The free edge or rim 13 of the valve 12 rests on the wall of the throat 9 in the ohtraating position (Fig.1 ) to close the outlet 10 against flow of material there through.

The valve 12 is reeiprocated between the obturating and 'open' positions by a lifting device 20 including a bellows means and an optional vibrator (not shown), for example like that described in U.K. Patent No, 2084969B. The lifting device 20 comprises a lifting cone or frusio-cone 21 which has a depending wall 22 concentric therewith. As is well known in the art, the lifting device could also be mounted above, in use, the valve.

Figure 2a shows a prior art valve. Such valves are well known in the art and typically have a conical shape. This shape can contribute in some circumstances to a problem associated with such known valves, where compression of products such as sugar causes the product to aggregate and block the outlet, reducing and/ or preventing the flow of product from the container. Figure 2b and 2c show the prior art valve of Figure 2a in combination with material discharge apparatus. Figure 2b snows the valve in the obturating position and Figure 2c shows the valve in the raised position. In use, the valve is reciprocated between obturating and open positions by a lifting device. In the closed, obturating position, unoonipacied powder 4 is shown above the valve, In the open, raised position, an area of compacted powder 105 forms around the valve, hi this embodiment, when the valve lifts into soft, compressible sticky powder it forms a zone of compaction which includes a cylindrical wall, directly adjacent to the lBC outlet, reducing and/ or preventing uncompacted powder from escaping through the outlet.

Figure 3 and Figure 4a shows a valve 12 for use with apparatus in accordance with the present invention. In this embodiment, the valve 12 comprises a cylinder (a right circular cylinder in this case). The cylinder has a side wail 79 that in this embodiment has a substantially smooth surface, and a circular end wall 80 which also has a substantially smooth surface. End wall 80 is provided with a centrally disposed loop 100 extending therefrom. The intersection 90 between the side wall 70 and end wall 80 (top surface) is relatively "sharp", being a 90 degree angle. At the opposite end of the side wall from end wall 80 the cylinder is open and has a hollow interior space 1 10. Thus the side wall defines a circular mouth 120 and the diameter of the circular month is such as to allow the fitment into the cylinder of a conical bottom wall 130, point uppermost, as viewed. The conical bottom wall 130 includes a seal element 140 that depends from its lower, as viewed, circumference. Referring in particular to Figure 4a, it car; be seen that the conical bottom wall rs disposed with the seal element 140 protruding from month 120, The use of a conical bottom wall 130 ensures that the valve 12 is compatible with commonly used valve lifting devices.

Figure 4b and 4c show a valve in accordance with an embodiment of the invention in combination with material discharge apparatus, wherein the valve moves between an obturating position and a raised position, In tins embodiment, the one or more sidewall 70 is disposed above the seal 140, Preferably, the one or more sidewall 70 is disposed, in use, within the material to be discharged when the valve is closed. 1 Ins embodiment has the advantage that it prevents a zone of compacted powder forming adjacent to the outlet of the IBC and therefore provides for discharge of a large volume of products such as sugar through the outlet. Figure 6a and 6b show a further embodiment of a valve in accordance with another embodiment of the invention. In this embodiment, the one or more sidewall 70 Is disposed above the seal 140. Preferably, the one or more sidewall is disposed, in use, within the material to he discharged when the valve is closed. This embodiment has the advantage that it prevents a zone of compacted powder forming adjacent to the outlet of the IBC and therefore provides for discharge of a large volume of products such as sugar through the outlet.

In this embodiment, the vertical sidewall of the valve has a shorter height than that shown in Figures 4b and 4b. Preferably, the vertical sidewall of the valve has a height which is substantially equal to or slightly greater dian the lift height of the valve. The provision of a valve having a vertical sidewall of shorter length prevents a zone of compacted powder forming adjacent to the outlet of the IBC. hi this embodiment, the uncompacted powder is able to flow through the outlet, creating a void into winch the compacted powder can then flow, thus allowing for discharge of a large volume of products such as sugar through the outlet. Advantageously, the provision of a vertical sidewall having a short height allows for production of the valve at lower cost con-spared with valves having a sidewail of longer length. In addition, the provision of a valve having a vertical sidewah of shorter length reduces the weight of the valve and improves the volume of power that may be accommodated when compared with a valve ha ving a longer length vertical sidewalh

It would he appreciated that in all embodiments, there is a discrete line of intersection between the sidewall (70) and the top surface (80) of the valve.

In use of the system 1 , assuming thai the station 3 has been charged at a remote location with a flowable material such as a pharmaceutical powder 4, the powder 4 is sealed in the bin by the valve 12 and by a suitable sealed lid 24. If it is desired to dose or discharge some of the powder 4 from the station 3, that station 3 is transported to the discharge station 2, At the discharge station 2, the lifting device 20 is m a lower or inoperative position with the lip seal 14 of the chute or hopper 6 substantially horizontal and engaging the external surface of the wall or skirt of the lifting cone 21. hi order to effect discharge of the powder 4, the station 3 is lowered onto the discharge station 2, by a fork lift truck whose forks are engaged in the feet 8 so that the lower edge of the station 3 can be received by the framework 7 of the discharge station 2. If now it is desired to dose arsd discharge powder 4 from the station 3, the vibratory lifting device 20 is actuated by air from the air source to raise the lifting probe or cone 21 to contact corneal bottom wall 130 of valve 12 and this action automatically raises the valve 12 too, so opening an annulns between the periphery of the valve 12 and the wail 9 of the station 3 and tiros a path ft'om the interior of the station 3 by way of the armnlus past the lifting device 20 into the discharge station, In some embodiments, a vibrator may he provided, carried by the lifting cone 21. This can also be activated by the air source and vibrates the valve 12 and lifting cone 21 and the powder 4 to ensure a smooth, controlled outflow through the annulus without bridging or rat-holing. During this flow the material 4 passes the b ee inner edge of the superposed seals 14 and 16 winch are held tightly together and which seal the outlet of the station 3 and the inlet to the station 2 against egress of powder externally of the system 1. When the required amount of powder 4 has been dosed the lifting device 20 is deactivated so that the lifting cone 21 and valve 12 descend rapidly under the weight of material 4, above the valve 12, and under gravity to roseal both the outlet of the station 3 and the outlet of the station 2.

As will be appreciated, it will not always be desirable for an 1BC to have a valve 12 that is optimised for use with flowable sticky particulates. Although it is possible to change valves, according to a further aspect of the invention, there is provided a method and apparatus to address this issue in the form of a valve kit that composes a known type of cone valve, and a valve cover 12 tor fitment to the cone valve, the valve cover 12 comprising one or more sidewall that is substantially parallel with ihe longitudinal axis of ihe chute,