A Crop Storage Container

Field of the Invention

The present invention relates to a storage container for retaining a crop, allowing fluid flow across the crop. The container can be linked to like containers allowing the fluid to flow from one container to a fluidly linked container.

Background to the Invention

Once a crop has been harvested, then the crop needs to be kept under controlled conditions, possibly to dry off excess water and then to maximise the quality of the crop over the storage period. For example, conditions need to be controlled to prevent the crop from drying out more than required, but also to reduce the occurrence of fungal or other microbial growth.

Additionally, many crops need to be treated chemically to assist in the above microbial control and also to prevent other pest species such as insects from attacking the crop. The problem with prior art systems is that the air flow is such that it is not consistent throughout the entire crop. Primarily this is due to the relatively large volume in which a crop is stored, which makes control more difficult. This results in some of the crop being well-ventilated, but also that some crop is in a "dead spot" where there is little or no flow. This latter state can be detrimental to the quality of the crop as it can lead to crop decay.

The present invention seeks to address the above problem by, in effect, dividing a larger storage volume into a plurality of smaller unit volumes in which air flow can be more easily controlled.

Summary of the Invention

According to a first aspect of the invention, there is provided a storage module for crops, the module comprising a storage volume having a floor on which a crop rests; an inlet chamber separated from the storage volume by a fluid barrier, the barrier including fluid inlets providing controlled fluid flow between the storage volume and the inlet chamber; an outlet chamber separated from the storage volume by a fluid barrier, the barrier including fluid outlets providing controlled fluid flow between the storage volume and the outlet chamber.

Conveniently, the size of a fluid inlet can be varied to control the flow of fluid.

Conveniently, the size of a fluid outlet can be varied to control the flow of fluid.

Optionally, the location of a fluid inlet can be changed to control flow of fluid.

Optionally, the location of a fluid outlet can be changed to control flow of fluid. The storage module is preferably cuboidal, including rectangular cuboidal to facilitate location of storage units in a space-efficient manner and with the inlets/outlets on adjacent storage modules in close proximity to each other to facilitate formation of a continuous fluid pathway between storage modules through linkage of fluid inlet and outlet chambers.

Conveniently at least one inlet and/or outlet chamber extends along one edge of a module allowing storage modules to be linked at corner edges.

Optionally an inlet or an outlet chamber is located beneath a storage volume and where the storage module is cuboidal extends across the lower in-use face of the storage module. Further optionally, an inlet or an outlet chamber is located above a storage volume and where the storage module is cuboidal extends across the upper in-use face of the storage module.

The storage module preferably includes a heat-exchanger to remove or add thermal energy into the fluid flow.

Brief Description of the Drawings

The invention is now described with respect to the accompanying drawings which show, by way of example only, five embodiments of a storage system. In the drawings:

Figures la, lb and lc illustrate ventilation ports in a container;

Figure 2 illustrates passive air flow through a container;

Figures 3a, 3b further illustrates passive air flow through a container to cool /heat respectively;

Figure 4 illustrates mechanical air flow through a container;

Figure 5 illustrates passive air flow through a stacked plurality of containers;

Figure 6 illustrates forced air flow through a plurality of containers; Figures 7a, 7b illustrate embodiments of a stacked plurality of containers, each including a heat exchanger with the embodiment of Figure 7a provided with cooling and that of Figure 7b with heating;

Figures 8a, 8b illustrate an array of containers having external common mechanical heating /cooling system and integrated ventilation ports; and

Figures 9a, 9b compare the current invention (Figure 9a) with a prior art arrangement (Figure 9b) of storage units.

Detailed Description of the Invention

The present invention is intended primarily for the agricultural sector in relation to crop storage. Modern farming and food distribution systems now often require that when a crop has been harvested, it is then stored for prolonged periods, possibly over months, before being sent to a retail distribution outlet. It is imperative therefore that the conditions under which the crop is stored minimise the degradation of the crop, including preventing microbial growth, and also controlling any growth or development of the crop.

Many methods of crop storage rely on maintaining the crop under constant, defined conditions and often include the step of passing an air current across the crop, the air being at a pre-defined temperature, humidity, oxygen content etc. Often other agents such as anti-fungal or insecticides can be added to prevent infestation of the crop.

One difficulty encountered concerns the storage facilities available at a particular site. This is often in the form of a barn or a specially built silo, usually having quite a large usable volume. Often therefore either a large volume of a single crop is stored or alternatively several crops are stored in the one volume. Neither alternative is ideal. In the former, the large volume means that there will be regions of the crop where the air does not reach: in the latter, the crops will likely require air having different characteristics, which is difficult to provide in one connected space. Although a barn, for example, could be divided up into several smaller volumes, the structure produced is then fixed and cannot be readily changed as the nature and volume of crops produced on a farm changes with time and from season to season.

The present invention addresses this in providing a modular unit which can be assembled with other units to provide a working volume whose overall size and configuration can be changed to suit the particular needs at the time. Moreover the invention can provide a standalone facility, having its own in-built ventilation control system, for example on a farm or also on transport such as a lorry or ship, or be incorporated into an already existing structure and ventilation system, enabling the structural volume to be effectively divided up into smaller, fluidly independent volumes.

The ability to couple the units into vertical stacks with integral ventilation with isolated controlled environments, allows the floor space to be utilised up to 100%. This enables the systems to act as large scale distributed environmentally controlled storage systems within any storage capacity. These two factors allow for roboticised top-loading thus not requiring space for the machinery traditionally moving in space near and/or between the storage units

Referring initially to Figures 1, these show different configurations of storage box, providing different fluid flow paths. A particular configuration is selected based on the requirements of the crop and the layout of any existing structure, including already installed ventilation /heat exchange systems. Figure la illustrates a first embodiment of a storage box 10 in which product is stored on the floor of a product volume 11. The embodiment of Figure la is provided with corner ventilation ports 12a, 12b and 13a and 13b. The ports 12a, 12b are designated as inlet ports 13a, 13b as outlet ports. In this preferred embodiment, in relation to the generally cuboid box 10, the inlets and outlets are diagonally opposite corners. An inlet or an outlet port can be provided with a closure to at least partially close the port when not required or to divert air flow in a desired path.

In Figure lb the storage box 20 has a product volume or container 21 on which product is stored and side ventilation ports 22, 23 of which the port 22 is designated as an inlet port and the port 23 an outlet port. Similarly, in respect of the storage box 30 of Figurelc, the product volume 31 is surmounted by a ventilation port 32 and is above a second ventilation port 33. Either of ports 32, 33 can serve as the ventilation inlet port.

The storage box can either be used by itself to store crop, or it can be combined with other storage boxes in such a way that the inlet and outlet ports of individual boxes combine together to form a flow path, which takes in each box, and is suitable for the crop being stored. Ventilation air can be provided by a built-in distribution system internal to one or more boxes or can be externally provided to the flow path from a separate distribution unit such as an HVAC or other air handling unit such as a mechanical fan or a compressed air source, a cooling or heating system including a heat pump or dehumidifier. The air supply can also be a passive air supply. Such a passive air supply can cause airflow through a box by convection currents created by pressure differences, typically arising from temperature differences.

A storage box can be provided in an overall shape to suit the use and intended location. A convenient shape for a box is cuboidal including rectangular cuboidal. This allows efficient use of space when locating boxes adjacent other boxes in rows and/or stacks.

The air supply itself can be from a bottled source or taken directly from the atmosphere. Additionally or alternatively, controlled gases or fluidised chemicals can be added to the flow, for example chlorine dioxide or chlorpropham can be added into the air supply where the stored crop is the potato. Other chemicals which can be used are ethylene gas, dimethylnaphthalene (DMN), Mint Oil (including R-carvone) and others which are commonly used in sprout prevention and control. Controlled atmospheres such as high CO? or N2 / low O2 environments also aids this, and also with other crops and fruits, slowing ripening or preventing their decay.

Regarding the dimensions of a box then this typically varies according to the crop being stored. For example, the small boxes containing fruit, a box of dimensions 300 x 300 x 200mm ³ can be used, whilst for potatoes, a box of 3000 x 3000 x 2000mm ³ can be contemplated. The walls of a box are made of materials known in the art and manufactured using conventional methodology.

In general terms, the air supply enters a box at an inlet point. The air then flows into the interior volume of the box by means of an opening, flap, floor or wall grating or the like to engage the crop. The air then exits the interior volume via an outlet. Depending on the layout of the storage facilities, the air is either vented to atmosphere or can flow to the inlet of a neighbouring box, or is recirculated, for example via a heat exchanger, dehumidifier, chemical purifier and back into the box via the box's inlet.

Referring now to Figure 2, this illustrates passively caused air flow through a storage box 40 in which movement of the air, shown by arrows A, through the box 40 is not brought about by mechanical means, but air movement is by means of convection forces. This embodiment is suitable for tubers such as potatoes, which because they are living and breathing creating a heat output driving the air current roughly >50w/Ton. Air enters a box 40 via the inlet chamber 41. Where the flow is based on differences in temperature then the inlet is preferably located towards the base of the box 40. The air then flows into the product volume 42 of the box 40 and flows in the direction indicated by the arrow. The air exits the product volume 42 and enters the exhaust chamber 43. Then again, in a temperature-difference based unit, the outlet from the exhaust chamber 43, preferably located towards the upper region of the box 40, instead of venting to atmosphere, the exhaust air can pass into a recirculation chamber 44. The recirculation chamber 44 preferably includes a heat exchanger which removes heat energy from the exhaust air. The cooled air can then flow directly into the inlet chamber 41 and back into the product volume 42.

In more detail and referring to Figure 3a, which illustrates a self-contained box 50 operating by heat difference to drive air flow, the cooled air from a heat exchanger 51 falls through the cold air inlet channel 52. Cold air then flows in the lower conduit 53 beneath the product volume 54. The cooled air enters the product volume 54 via air inlets 55. After passing through the product within the product volume 54, the now warmed air, flows upwards and out of the return vent 56 and into the return conduit 57. The air in the return conduit 57 is cooled by passing through the heat-exchanger 51, before flowing back into the cold air inlet channel 52. An inlet chamber or conduit typically extends across a face of the product volume to ensure airflow can reach all parts of the product volume.

In an optional embodiment, not illustrated the size of an air inlet or an air outlet can be changed to provide the airflow required. In a further optional embodiment, the location of an air inlet or an air outlet can be moved: again to provide the required flow characteristics through a storage volume.

Figure 3b illustrates a storage box 60, operating similarly to the box 50 in driving air flow by temperature difference, but provides instead for a warmed air feed. In the box 60, a heat exchanger 61 located in the base of the box 60 heats air which flows up the inlet channel 62 and along the top conduit 63. The warmed air enters the product volume 64 through the chamber inlet 65 flowing thence through the product in the volume 64, losing heat to the product as it does so. The cooled air exits the volume 64 by the outlets 66 and the lower conduit 67. The cooled air in the conduit 67 is then reheated by the heat exchanger 61 before passing again into the inlet channel 62.

In Figure 4, the storage box 70 illustrated as shown including mechanical means, such as a fan or the like, to drive air through the system. The mechanical means can be incorporated into one or both of heat exchangers 71 or 72 which respectively cool circulating air or heat circulating air within the storage box 70 in the conduits 73, 74, 75. In a preferred embodiment, one or both of the mechanical means and the heat exchangers can be housed in a separate unit fluidly attachable to a storage box. The separate unit can be part of a larger structure in which the product boxes are utilised. It can be envisaged therefore that a building be provided with one or more inbuilt heat exchangers and/or mechanical means to drive air flow, to which storage boxes as described herein can be fluidly attached. This simplifies the provision of an electric supply to the heat-exchangers /mechanical means, although a limitation can thereby be imposed on where a storage box can be located within the building during use. The array of storage boxes illustrated in Figure 5 has three storage boxes 80a to 80c in a stacked arrangement. The boxes 80a to 80c as shown, conform to the storage box 20 of Figure lb. However, the other embodiments of a storage box can also be utilised in such an arrangement. The boxes 80a to 80c are arranged such that the inlet ports 22 of the boxes 80a to 80c cooperate to form a fluid path and similarly the outlet ports 23.

Cooled air from the recirculation chamber 81 can therefore reach any of the boxes 80a to 80c and similarly, warmed air exiting each of the boxes 80a to 80c combines together into a single air flow to return to the recirculation chamber 81 for cooling.

The boxes which are the subject of the present invention enable, in effect, a storage volume to be enlarged or reduced to suit a particular crop being stored. When the crop has been harvested therefore, individual storage boxes can be assembled together to accommodate the crop. As the crop leaves for onward processing, individual boxes can be removed from the assembly, and reused for another crop being harvested. The stacking together can also offer, where required, a lower heat loss than three individual boxes due to the smaller external surface area of the assembled boxes compared with the same number of boxes individually stored.

The arrangement of boxes 90a to 90c in Figure 6 is similar to that shown in Figure 5. In this arrangement however two of the boxes 90b, 90c are of the type shown in Figure lb, whereas the box 90a is of the type shown in Figure 4 and includes mechanical drives 91, 92 to drive air through the arrangement. The drives can be incorporated into, or coupled with, heat exchangers which act to remove /add heat to the air being circulated. Also, similarly to the embodiment of Figure 4, the drives /heat exchangers can be incorporated into the building in which the boxes are housed. In a further embodiment, not illustrated, a storage box having integrated drives/heat exchangers can be permanently installed within a structure, with removable storage boxes then being added to the permanently installed box as and when required. Regarding Figures 7a, 7b these show arrangements of storage boxes in which two stacks of storage boxes are arranged adjacent each other and ventilation /heat exchange is provided by one or more units, to both stacks. The arrangements of Figures 7a, 7b are representational as to how boxes can be combined. Arrangements can be designed for any number of boxes stacked and only limited by the method of stacking or height of the store.

In Figure 7a, an array of two stacks 100, 101 each comprising three storage boxes 100a to 100c, 101a to 101c are each connected to a mechanical cooling unit 102. The two stacks are provided such that each defines and is served by a separate fluid flow path, beginning and ending with the cooling unit 102. The two stacks are separated by a dividing wall 103, across which air does not flow. This facilitates partial disassembly of the array to remove, for example, boxes 100a to 100c but leaving the other stack in place.

Cooled air, produced by the mechanical cooling unit 102, is discharged into the cooling duct 104 in the direction of the arrow A. Due to its higher density, the cooled air moves in a generally downward direction. As the cooled air descends, a portion of it diverts beneath each storage box 100a - c, 101a - c and enters a box by means of air inlets 105. As the air encounters product in the product volume 106, the air warms and rises to the top of the storage boxes 100a - c, 101a - c before exiting the box. The warmed air then rises to the top of the stacks 100, 101 by means of the fluid path formed by the outlets of the boxes 100a - c, 101a - c, to return to the mechanical cooling unit where the air is cooled and then again enters the cooling duct 104.

Figure 7b shows a similar arrangement except that the mechanical cooling unit 102 is absent and instead a mechanical heating unit 107 is included towards the base, beneath the stacks 110, 111. The heating unit 107 heats the air which then rises up the duct 114, in the direction shown by the arrow B, before entering the inlets at the top of the boxes 110a - c, Illa - c, thence heating the product, before exiting the boxes 110a - c, Illa - c via the outlets 115. Figure 8a illustrates an array comprising horizontal rows 120, 121, 122 of boxes 120a - e, 121a - e and 122a - e. The boxes in the rows 120, 121, 122 are of the type of box illustrated in Figure 7a and having air inlets 125 in their base regions. Each horizontal row 120, 121, 122 is served by an individual duct 123a, 123b, 123c which runs continuously under each of the boxes in an individual row. Unlike the arrangements in Figures 7 therefore, air can flow horizontally across a nominal stack of vertically neighbouring boxes such as that formed by the boxes 120a, 121a, 122a.

A mechanical cooling unit 126 acts to cool air prior to the air entering a product volume. The cooled air therefore leaving the mechanical cooling unit 126 flows downwardly in the duct 127. Portions of the cooled air can flow into the ducts 123a, 123b, 123c from where the air enters a box located over the particular duct through an inlet 125. On leaving the box the air has entered, the air can either continue an upward journey through a box in a higher row or move horizontally along the duct it is now in, reaching the further duct 128 from which it flows back to the mechanical cooling unit 126.

In Figure 8b, a similar arrangement is illustrated, with the mechanical cooling unit being replaced by a mechanical heating unit 130 to heat air, which then rises upwardly and/or horizontally along the ducts before descending back to the mechanical heating unit 130.

Figures 9a and 9b illustrate, respectively, an embodiment of the current invention and compares this embodiment with a prior art storage arrangement. In Figure 9a, 4 columns of storage units, with a ventilation unit atop each column require, in effect an area of floorspace equal to the sum overall of the floorspace of each column. The loading and unloading of product is provided by a single unloading/loading machine. This arrangement compares favourably with that of the prior art arrangement shown in Figure 9b. The arrangement of Figure 9b also includes four columns of storage units, served by a central ventilation unit. However, the storage units are separated spatially, horizontally, to allow the unloading/loading machine access. The overall floor space utilized is therefore greater.