Field of the Invention

The invention relates to washers for cleaning vegetables, especially root vegetables, and particularly to barrel washers.

Background to the Invention and prior art known to the applicants

Root vegetables, such as potatoes, are washed after harvesting and before further processing, e.g. storage and packaging. Barrel washers, or tubular vegetable washers, are conventionally used in the agricultural sector to wash root vegetables on a large scale.

Potatoes, for example, are fed into a barrel washer and water, or another washing solution, is applied to the potatoes to wash them as they travel along the drum of the washer towards an outlet or collection bin.

The drums of barrel washers are typically cylindrical and have a circular cross section. Root vegetables should therefore roll along an inner surface of the drum or be caused to tumble into each other as the drum rotates. This movement helps to clean the root vegetables. An improved barrel washer is sought.

The following prior art documents are acknowledged: RU179546U and US2004/022908. Neither of these documents present an elliptical tube with a portion of an outer surface having a substantially circular cross-section.

Summary of the Invention

The present inventive concept is directed to a vegetable barrel washer comprising a drum rotatable about a longitudinal axis of the drum; the drum having a vegetable inlet, a vegetable outlet and an internal surface for contacting vegetables to be cleaned; wherein the internal surface of the drum defines a substantially elliptic tube; and wherein the tube has at least a portion having an oval axial cross-section.

An axial cross-section for the purposes of this description is intended to describe a planar section substantially orthogonal to the longitudinal axis of the drum.

The barrel washer provides improved cleaning of vegetables.

The oval portion of the tube causes vegetables to roll and fall over one another within the drum. By contrast, a tube with only a substantially circular shape would not cause vegetables within the drum to fall over one another as effectively. With a circular shape, vegetables may slide along the internal surface of the drum and not fall over one another. The oval shaped tube of the present invention reliably prompts the tumbling of vegetables so that they are cleaned more effectively and efficiently.

The throughput of the washer is improved because vegetables are more efficiently cleaned and thus, because the throughput is improved, a similar volume of vegetables may be washed by a smaller barrel washer or in a shorter amount of time compared to existing barrel washers. The oval shaped tube improves washing levels whilst minimising the risk of damage to vegetables.

The tube is wider in one direction (a first diameter) than in another direction (a second diameter) along at least part of the longitudinal axis, i.e. the length of the drum. The first and second diameters may be substantially perpendicular to one another.

The second diameter may be at least one of 5%, 10%, 20%, 30% or 40% smaller than the first diameter.

The tube may have an axis of symmetry. The tube may have more than one axis of symmetry. The tube may have two axes of symmetry which are substantially perpendicular to one another. In other words, the tube may have the shape of a simple oval which may be hypothetically split into four quarters which are each symmetrical to their adjacent quarters.

A simple oval shape causes regular and predictable tumbling of vegetables within the drum as it rotates about the longitudinal axis. The apices of the oval tube cause vegetables to crowd at each apex, and then fall away from each apex as the drum rotates. The crowding and falling of the vegetables causes them to roll over one another more effectively to improve cleaning.

The tube may be substantially egg shaped. An egg-shaped tube causes irregular tumbling within a single revolution of the drum, which is beneficial for batches of vegetables of irregular shape.

The tube may have a first diameter which is approximately 1000 mm in one direction and a second diameter which is approximately 1200mm in another direction.

The tube may be oval along substantially the entire longitudinal axis.

The tube may comprise two or more sections spaced along the longitudinal axis, wherein at least two sections have a different shape to one another. For example, a first section of the tube may have an oval axial cross-section and a second section may have a circular axial cross-section. A change in shape of the tube along the longitudinal axis triggers changes in movement of the vegetables as they travel towards the outlet.

The drum may comprise a continuous track incorporating several plates. Thus, the drum need not be a rigid structure and the oval axial cross-section of the tube may be adjusted to improve vegetable washing.

The internal surface of the drum may comprise one or more agitators. The or each agitator causes additional movement of a vegetable within the drum by jerking a vegetable when the vegetable reaches an agitator.

Additional movements cause more tumbling of the vegetables within the drum. More tumbling increases contact time between vegetables and/or between each vegetable and the drum, which improves cleaning.

At least one said agitator may comprise a strip which protrudes from the internal surface towards the tube, and may extend at least partially parallel to the longitudinal axis. The strip may extend along substantially the entire longitudinal axis of the drum. The strip may extend substantially radially to the longitudinal axis.

The or each strip may extend substantially helically around the longitudinal axis. The strip therefore defines an internal screw which controls the movement of vegetables for improved cleaning efficiency. More specifically, as well as agitating vegetables, the helical configuration of the strip urges vegetables towards the outlet.

At least one agitator may comprise a knob which projects from the internal surface towards the tube. The internal surface may comprise a plurality of knobs.

An or each agitator may be made substantially of a resilient material. The risk of damage to vegetables is thus minimised. An or each agitator may comprise rubber. An or each agitator may be comprised of another resilient material to the same end.

An or each agitator may have a substantially triangular, square, circular or semi-circular cross-section. The internal surface may comprise one or more indents. An indent causes additional movement of vegetables within the drum to improve cleaning efficiency. An indent may extend towards the tube or away from the tube. The washer may comprise several indents which are spread relatively evenly across the inner surface of the drum.

The internal surface may comprise one or more perforations for allowing a washing solution to flow into or out of the tube defined by the internal surface. The perforations allow fresh washing solution to enter the tube. The perforations also allow soiled solution to exit the tube to improve cleaning.

The tube may be at least partially submerged in a washing solution.

At least partially submerging the tube ensures that vegetables are adequately coated in a washing solution to facilitate cleaning. Approximately half of the tube may be submerged in a washing solution. The drum may be at least partially submerged in a washing solution.

The barrel washer may comprise one or more sprinklers for spraying vegetables with a washing solution. A sprinkler improves the coating of vegetables with a washing solution.

The barrel washer may further comprise a number of belts which facilitate rotation of the drum. The belts may contact an outer surface of the drum.

The outer surface of the drum may comprise a number of receiving portions configured to cooperate with the belts. The receiving potions may be annular, i.e. they may extend circumferentially around the outer surface of the drum. The receiving portions may be regularly spaced along the length of the drum. The receiving portions and cooperating belts may be spaced approximately 1 metre from one another along the length of the drum. Advantageously, at least an external portion of the drum may define a circular perimeter. In certain embodiments, these portions may be part of annular recess or a bearing in order to maximise the efficiency of the transmission of rotation to the elliptical tube.

The washer may further comprise a motor and at least one belt may be driven by the motor. At least one of the belts may be a passive belt which facilitates rotation of the drum but is not directly driven by a motor. The washer may comprise two or more belts which are each driven by a rotating drive shaft. The outer surface of the drum may have a substantially circular axial cross-section.

The or each receiving portion may have a substantially circular axial cross-section.

The speed of rotation of the drum is such that the vegetables roll over themselves to obtain a sufficient cleaning level, whilst minimising damage to the vegetables. The speed of rotation of the drum may be between around 7 rpm to around 20 rpm. The speed of rotation of the drum may be approximately 12 rpm.

The drum may have a length of between around 2 metres to around 6 metres.

The drum may be comprised of stainless steel.

The barrel washer may further comprise means for feeding vegetables into the inlet and/or collecting vegetables from the outlet.

The barrel washer may further comprise a reservoir for a washing solution. The barrel washer may further comprise one or more pumps for pumping a washing solution into or out of the tube defined by the internal surface.

The barrel washer may further comprise a housing which encloses the other components of the washer.

Thus, the washer may be transported and used at a harvest site. Where the housing encloses a reservoir, the barrel washer need not be connected to an external water supply and so the barrel washer may be used in locations where an external water supply is not available.

Thus, vegetables do not need to be transported to a washing facility before further processing. This would reduce transportation requirements and thus would be potentially energy efficient and emissions reducing. Detailed description of the invention

Exemplary embodiments of the present inventive concept will now be described with reference to the accompanying drawings, in which:

Figure 1 shows a perspective view of a barrel washer drum;

Figure 2 shows an axial cross-section of the barrel washer drum of Figure 1;

Figure 3 shows a side view of the barrel washer drum of Figure 1;

Figure 4 shows a perspective view of a barrel washer drum comprising perforations;

Figure 5 shows a semi-transparent perspective view of a barrel washer drum comprising an agitator;

Figure 6 shows a perspective view of a barrel washer comprising belts; and Figures 7 A to 7C show perspective views of examples of agitators.

Turning to Figure 1, a section of a barrel washer 10 has a generally cylindrical drum 12. The drum 12 comprises an inlet 14 for vegetables to be cleaned to enter the drum 12, and an outlet 16 for cleaned vegetables to exit the drum 12. The drum 12 further comprises an internal surface 18 which, in use, contacts vegetables which enter the drum 12 via the inlet 14. The internal surface 18 defines a hollow tube 32 through which vegetables pass in use.

The tube 32 defined by the internal surface 18 is substantially oval shaped. The tube 32 is substantially oval along the entire length of the drum, i.e. the longitudinal axis. In a further embodiment, the tube may be circular in cross-section at the distal extremities of the tube and oval in cross-section for part or the entire length between said distal extremities.

The drum 12 further comprises receiving portions 22 configured to engage belts which drive rotation of the drum 12. These may advantageously comprise an annular recess which possesses a circular perimeter. In use, the drum 12 rotates about a longitudinal axis (marked in Figure 1 with a dashed line). Vegetables are fed into the drum 12 and are washed as they travel through the tube 32 towards the outlet 16. They are then collected at the outlet 16 for further processing.

Figure 2 shows a cross-section of the drum 12. The tube 32 defined by the internal surface 18 has an oval axial cross-section. An outer surface 20 of the drum 12 has a circular axial cross-section. Thus, some portions of the internal surface 18 are spaced further from the outer surface 20 than other portions of the internal surface 18.

In Figure 2, the tube 32 has a vertical diameter which is greater than a horizontal diameter of the tube 32. The vertical and horizontal diameters are perpendicular to one another and both are perpendicular to the longitudinal axis of the drum 12.

The tube 32 forms a simple oval in that it has two axes of symmetry which are substantially perpendicular to one another. The top half of the drum 12 is roughly symmetrical to the bottom half and the right hand side of the drum 12 is roughly symmetrical to the left hand side. The drum 12 of Figure 2 has a vertical diameter of 1200mm and a horizontal diameter of 1000mm.

Referring to Figure 3, the drum 12 comprises three receiving portions 22. The receiving portions 22 are configured to receive a belt for rotation of the drum 12. Each receiving portion comprises an annular channel which extends circumferentially around the outer surface 20. The channel is defined by two flanges which extend away from the outer surface 20. A belt sits within the channel of a receiving portion 22. A motor (not shown) is connected to at least one of the belts via a drive shaft.

Figure 4 shows a similar drum to that shown in Figures 1 to 3. The internal surface 18 comprises a plurality of perforations 26 for allowing a washing solution to enter the tube 32. The perforations 26 are large enough to allow a washing solution to enter and exit the tube 32 but small enough to prevent vegetables from exiting the tube 32. Perforations 26 are shown in certain regions of the drum 12 only for the sake of clarity. The skilled reader will appreciate that the distribution of perforations 26 may be more comprehensive in practice.

In use, a washing solution may enter the tube 32 via the perforations 26 and the drum 12 is rotated. Rotation of the drum 12 causes vegetables, which have entered via the inlet 14, to tumble. Tumbling of vegetables occurs because the internal surface 18 lifts vegetables in the direction of rotation of the drum 12, and gravity causes the vegetables to fall when gravitational force overcomes the frictional force between a vegetable and the internal surface 18 (or between vegetables). The washing solution coats vegetables and, together with the tumbling movement, acts to remove unwanted material from the vegetables.

Referring to Figure 5, the internal surface 18 comprises an agitator in the form of a helical strip 28. The strip 28 protrudes from the internal surface 18 towards the tube and extends along the length of the tube 32.

The helical strip 28 extends along substantially the entire length of the drum 12. The helical configuration of the strip 28 directs vegetables towards the outlet 16 where vegetables will then be collected for further processing. The strip 28 is comprised of a resilient material to minimise damage to vegetables as they are pushed towards the outlet 16.

Referring to Figure 6, the barrel washer 10 further comprises belts 30 which engage and cooperate with the receiving portions 22 to rotate the drum 12. The belts 30 extend from above the drum 12 and cradle the drum 12. The belts 30 sit within the channel formed by the two circumferential flanges of each receiving portion 22.

The drum 12 of Figures 1 to 6 is approximately 2 metres long, and the receiving portions 22 and belts 30 are regularly spaced at around 1 metre intervals along the length of the drum 12.

Figures 7A, 7B and 7 C show examples of agitators 28'. The agitator 28' of Figure 7 A has a circular cross-section. The agitator 28' of Figure 7B has a square cross-section. The agitator 28' of Figure 7C has a triangular cross-section. The barrel washer 10 may comprise several agitators 28, some of the agitators having different cross-sections to one another.

A barrel washer according to the inventive concept may comprise each of the features described with reference to Figures 1 to 6. For example, a barrel washer exemplifying the present inventive concept may have one or more agitators, and perforations and belts.