GB2349804A

GB2349804A - A washer for root crops and tubers

Info

Publication number: GB2349804A
Application number: GB9925832A
Authority: GB
Inventors: Maxwell Edward Howard; Christopher Ross Howard
Original assignee: FRESH GROWERS Ltd
Current assignee: FRESH GROWERS Ltd
Priority date: 1999-05-13
Filing date: 1999-11-02
Publication date: 2000-11-15
Anticipated expiration: 2019-11-02
Also published as: GB9925832D0; GB2349804B; GB9911005D0

Abstract

A washer for cleaning soil and stones from root crops and tubers comprising a tank (1) adapted to be filled with water, conveyor means (5,6) for conveying dirty crops introduced at one end of the tank (1) through the water therein to an outlet point at the other end, and means (11) for agitating the water within the tank to effect a cleaning action on the dirty crops as they pass along the conveyor means (5,6).

Description

2349804 DESCRIPTION "A WASHER2 The present invention relates to a washer

for root vegetables and tubers and, in particular, for washing carrots. More specifically, but not exclusively, the present invention provides a mobile washer which can be used in conjunction with a harvesting machine to wash the crop as it is taken from the ground.

After a crop of root vegetables or tubers has been harvested it is usually transported from the place of harvesting to static washers in which any soil adhering to the crop is washed off. These static washers rely principally on mechanical agitation of the crop to clean off the dirt. In this regard, the washer may consist of either a barrel washer or a brush washer or a combination of the two. It is not unusual to have to transport crops considerable distances to reach the nearest static washers.

There are a number of problems associated with the use of static washers.

Not least of these is the additional haulage cost incurred by the farmer in transporting his crop together with large amounts of soil and stone to the static washer. A further disadvantage associated with transporting dirty crops is that the soil tends to abrade and cause damage to the skin of the crop, "Ist this skin damage may not actually spoil the crop it can result in a shorter shelf life. Yet another disadvantage associated with the use of static washers is that the dirty water resulting from washing crops must be cleaned before it can be released into the environment. If the dirty water 2 were to be released directly into drains or rivers it would soon result in silting up.

In order to clean the water settling out beds must be provided with the additional capital costs that these entail. Moreover, the soil and debris collected after washing the crop must be disposed of.

It is an object of the present invention to provide a mobile washer in which root crops and tubers can be washed as they are harvested, thereby obviating or at least substantially mitigating the problems associated with static cleaners referred to hereinbefore.

According to the present invention there is provided a washer for cleaning soil and stones from root crops and tubers comprising a tank adapted to be filled with water, conveyor means for conveying dirty crops introduced at one end of the tank through the water therein to an outlet point at the other end, and means for agitating the water within the tank to effect a cleaning action on the dirty crops as they pass along the conveyor means.

Preferably, the conveyor means comprises of a close pitch continental web which allows a crop to be conveyed from the intake end of the washer, and soil and grit washed from the crop to pass through the web into the bottom of the washer.

Preferably, one or more aeration bars is provided beneath the web conveyor.

Each aeration bar emits a stream of bubbles which pass up through the web conveyor and agitate the water around the crop to enhance the cleaning action thereof on the crop.

Preferably, a collection vessel is provided in the floor of the washer in which 3 the soil and grit washed from the crop is collected. A discharge gate valve may be provided at the top and the bottom of the collection vessel to allow the soil and grit to be discharged therefrom without excessive loss of water.

Preferably, the washer flirther comprises a second conveyor which receives material discharged from the first conveyor and carries it out of the washer.

Preferably, a finiher aeration bar is provided between the first and second conveyors.

This further aeration bar causes the crop to be carried onto the second conveyor whilst allow heavy material mixed with the crop to fall down to the bottom of the bath. This heavy material is preferably collected in the said collection vessel or in a further collection vessel provided specifically for this purpose. Where a further collection vessel is provided it too may be fitted with discharges gate valves at the top and bottom.

Preferably a clean water sluice is provided above the second conveyor at or after the point where it emerges from the water in the washer.

The washer may be static, in which case crops to be cleaned must be transported to it. However, in a preferred embodiment of the present invention the washer is mobile. Where the washer is mobile it may be self-propelled or may be adapted to be towed behind a motorised vehicle, such as a tractor.

Preferably, the washer is provided with means for re-circulating the water in the tank. Preferably, the mobile washer is provided with a source of clean water for effecting a final rinse of the crop immediately before it is output from the mobile washer.

4 An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 shows a side view of a schematic representation of a mobile washer for root crops and tubers embodying the present invention; and, Figure 2 shows a plan view of the mobile washer shown in Figure 1.

Referring to the drawings there is shown a mobile washer comprising a box shaped tank 1 which is divided into a closed lower compartment 2 and an upper open topped bath 3 by a dividing wall 4. The lower compartment 2 forms a reservoir for clean water which can be pumped into the bath 3 to top it up as required. A pump (not shown in the drawings) is provided for this purpose. Crops to be cleaned are introduced into the bath 3 at the head end thereof (the deep end) and are conveyed by a first continuous belt conveyor 5 and a second continuous belt conveyor 6 in turn to the tail end (the shallow end) of the bath 3. By the time the crop reaches the tail end of the bath it has been cleaned of soil and stones and is ready to be discharged from the bath.

The first conveyor 5 is fully submerged in the water in the bath 3 and extends horizontally from the head end of the bath 3 towards the middle thereof. The conveyor 5 is comprised of a close pitch continental web 7 which is supported between a pair of pulleys or sprockets 8 and 9. A motor (not shown in the drawings) is connected to one of the pulleys or sprockets 8, 9 to drive it and the belt 7 in the direction of arrow A. Situated at longitudinally spaced intervals beneath the upper web 10 of the belt 7 are aeration bars 11. Each aeration bar 11 extends transversely to the upper web 10 of the belt 7.

The web from which the belt 7 is fabricated allows soil and small particles of grit which are washed ftom a crop traveling forward on the upper web 10 thereof to pass through. It also allows the bubbles of air 12 from the aeration bars I I to pass through the upper web 10 and gentle agitate the water in the immediate vicinity of the conveyed crop. This agitation helps the washing action of the water on the crop.

Soil and grit washed from the crop which is small enough to pass through the mesh of the belt 7 fall to the bottom of the bath 3 leaving the crop and any larger stones on the upper web 10 of the belt 7.

In the region of the bath 3 immediately beneath the conveyor 5, the dividing wall 4 or floor forms a funnel which at its lowermost point leads into a discharge pipe 13. At the upper and lower ends of the discharge pipe 13 is provided a discharge valve 14 and 15. Each discharge valve 14 and 15 is independently controllable by means of an hydraulic ram (not shown in the drawings).

During washing of a crop the lower discharge gate valve 15 is closed and the upper discharge gate valve 14 is opened to allow soil and grit falling from the conveyor 5 and down the sides of the funnel to collect in the discharge pipe 13.

When the discharge pipe 13 becomes filled with soil and grit the upper discharge gate valve 14 is closed to isolate the discharge pipe 13 from the bath 3 and the lower discharge gate valve 15 is opened to allow the soil and grit to empty from the discharge pipe 13. With the discharge pipe 13 emptied the lower discharge gate valve 15 can be closed again and the upper one opened to allow the process to be 6 repeated. By collecting the soil and grit washed from the crop and periodically discharging it from the washer, the water within the washer is kept cleaner for longer and more crop can be processed with a given quantity of water. It will be appreciated that this is particularly important with a mobile washer which may find itself being used away from a supply of clean water.

Situated between the first and second conveyors 5 and 6 and somewhat beneath the two is a further aeration bar 16 which extends transversely across the bath 3. As the washed crop, together with any stones which were to large to pass through the web of the belt 7, are discharged from the end of the first conveyor 5 they are caught in the stream of air bubbles 17 rising upwards from the aeration bar 16.

It will be understood that the crop has a relatively low density when compared with the stones and will, therefore, rise to be carried forward on to the intake end of the second conveyor 6, whilst the stones will drop down towards the bottom of the bath 3. Note - the bubbles (17) create a flow of water as indicated by arrow W.

Is The second conveyor 6 is inclined upwardly from the middle of the bath 3 to the tail end thereof and this has the effect of allowing water to drain from the crop back into the bath 3 as the crop is carried towards the discharge end of the second conveyor 6. Situated above the second conveyor 6 and just before the discharge end of it is a clean water sluice 18 which sprays clean water onto the crop. This ensures that any small particles of soil and grit which were in suspension in the water and became caught up with the crop as it exited the water are washed back down into the bath 3. The clean water for the sluice 18 is obtained from the reservoir 2 under the 7 bath. It will be understood that the preferred method of operation is to ensure that the flow rate of water through the sluice matches that lost from the bath 3 during operation of the washer.

llie larger stones which fall down past the aeration bar 16 are collected in and discharged from the washer through a discharge pipe 19 having an upper and a lower discharge gate valve 20 and 2 1, respectively, which operate in the same fashion as the discharge pipe and valves 13, 14 and 15. This second discharge pipe 19 is, like the first discharge pipe 13, effective in allowing waste material to be collected and discharged from the washer without the loss of large quantities of water.

In use the mobile washer is situated beneath the outlet chute of a harvester towed behind a tractor. From the outlet chute of the harvester the dirty crop drops into the mobile washer at the head end thereof. The mobile washer may be self propelled, in which case it is driven alongside the harvester or it may be towed behind a further tractor.

It has been found that by washing the crop as it is harvested from the ground, any soil and stones adhering to it can be washed off quite easily and certainly more easily than is the case when the crop has been in transport for a considerable period of time to reach a static washer. It is felt that this may be due to the fact that washing takes place before the soil has had time to dry out and harden.

20............................................................ 1

Claims

8 CLAIMS

1. A washer for cleaning root crops and tubers comprising a tank adapted to be filled with water, conveyor means for conveying dirty crops introduced at one end of the tank through the water therein to an outlet point and means for agitating the water within the tank to effect a cleaning action on the dirty crops as they pass along the conveyor means.

2. A washer according to claim 1, wherein the conveyor means comprises a close pitch continuous web or mesh which allows soil and grit washed from the crop to pass through the web or mesh.

3. A washer according to claim 2, wherein one or more aeration bars is provided beneath the web or mesh conveyor.

4. A washer according to claim 1, 2 or 3, wherein a collection vessel is provided in the floor of the washer in which soil and grit washed from the crop is collected.

5. A washer according to claim 4, wherein discharge gate valves are provided at the top and at the bottom of the collection vessel each of which discharge gate valves is independently operable to allow soil and grit to be discharged from the collection vessel without excessive loss of water.

6. A washer according to claim 1, wherein the conveyor means comprises first and second conveyors arranged in series between the said one end of the tank and the said outlet point, the first conveyor receiving dirty crops introduced 9 at the said one end of the tank and the second conveyor receiving crops discharged from the first conveyor and carrying them out of the washer.

7. A washer according to claim 6, wherein the first conveyor means comprises a close pitch continuous web or mesh which allows soil and grit washed from the crop to pass through the web or mesh.

8. A washer according to claim 7, wherein one or more aeration bars is provided beneath the web or mesh conveyor.

9. A washer according to claim 6, 7 or 8, wherein a further aeration bar is provided in a gap defined between the adjacent ends of the first and second conveyors such that relatively heavy material, ie. stones, fall down through the gap, whilst relatively light material ie. crops pass from the first conveyor to the second conveyor over the gap.

10. A washer according to any one of claims 6 to 9, wherein a first collection vessel is provided beneath the said first conveyor and a second collection vessel is provided beneath the gap between the said first and second conveyors.

11. A washer according to claim 10, wherein discharge gate valves are provided at the top and at the bottom of each collection vessel each of which discharge gate valves is independently operable to allow material to be discharged from the collection vessel without excessive loss of water.

12. A washer according to any one of claims 6 to 11, wherein a clean water sluice is provided above the second conveyor at or after the point where it emerges from the water in the tank.

13. A washer according to any preceding claim, which is mobile.

14. A washer according to any preceding claim, comprising means for recirculating water in the tank.