WO2001026489A1

WO2001026489A1 - Device for washing agricultural products

Info

Publication number: WO2001026489A1
Application number: PCT/EP2000/009672
Authority: WO
Inventors: Stephanus Michael Marie Backus
Original assignee: Backus Sormac B.V.
Priority date: 1999-10-14
Filing date: 2000-09-29
Publication date: 2001-04-19
Also published as: AU1021101A; EP1220623A1; CA2383083A1; NL1013291C2

Abstract

Device for washing objects, more particularly agricultural products, such as bulbs or tubers, including a reservoir (10) with a washing liquid, means for conveying agricultural products close to one end (16) of the reservoir (10), and means for discharging agricultural products from another end of the reservoir (10), whereby means (40, 41, 45, 46) are present near the bottom of the reservoir (10) for conveying and blowing a gas into the reservoir (10).

Description

Device for washing agricultural products

The present invention relates to a device for washing objects, more particularly agricultural products, such as bulbs or tubers, comprising a reservoir with a washing liquid, means for conveying agricultural products close to one end of said reservoir, and means for discharging agricultural products from another end of said reservoir. Such a device is known.

In such a known device, the washing liquid is set in motion by mechanical stirring organs so that an adequate washing of the objects can be carried out. In the case of sensitive agricultural products, this does not always give the expected result, since the mechanical stirring organs may damage the agricultural products. On the other hand, agricultural products may be strongly loaded with ground residues that are to be eliminated upon washing and can easily foul up the motion mechanism of the stirring organs after separation and lead to a significant wear.

The aim of the invention is to provide a device of the above mentioned type, whereby the above mentioned disadvantages could be overcome. This aim is reached according to the invention in that means are present near the bottom of the reservoir for conveying and blowing a gas into the reservoir.

Thus, objects can be fully washed without using any mechanical stirring organs. The air blowing means are preferably arranged in such a way that a number of vertical zones with air bubbles are formed that are arranged behind one another between the feeding end and the discharging end and the gas transportation to the separate vertical zones is controlled in such a way that each time only one of two successive zones is activated.

Thereby it is obtained that the objects, because of the formation of alternate air bubble zones or screens, are automatically conveyed from the feeding end to the discharging end.

Other characteristics and advantages of the invention will become apparent from the following description wherein the accompanying drawings are referred to. In these drawings : Fig. 1 is a schematic top view of a device according to the invention,

Fig. 2 is a front view of the device in Fig. 1,

Fig. 3 is a side view from the feeding end of the device in Fig. 1, and

Fig. 4 is a side view from the discharging end of the device in Fig. 1.

The device according to the invention as illustrated in Figs. 1-4 includes a frame formed with a number of vertical feet 4, in the illustrated embodiment six, that are arranged in pairs and are connected with one another near the upper ends through crosspieces 5. Each time, three feet 4 are mounted on one line and mutually connected near the upper ends through longitudinal members 6.

In the so-formed frame, an elongated tank 10 is installed which, seen in a cross sectional view (Fig. 3), is made of an upper part 11 with a rectangular cross section and being laterally limited by two longitudinal walls 60, 61, a median part 12 with a frusto-conical cross section and limited by walls 62,

63, a lower part 13 with a rectangular cross section and being laterally limited by two longitudinal walls

64, 65 and a bottom part 14 with a frusto-conical cross section, whereby the height of this part becomes progressively larger from a first end 16 of the tank 10 to the other end 17 (see Fig. 2), thereby producing an inclined bottom plate 8.

The end 16 of the tank 10 is closed with a plate with an appropriate shape corresponding to the local cross section. The end 17 is closed on the one hand by two plates 18 that form an angle with the vertical and an angle with the longitudinal direction of the tank, so that, as shown in Fig. 1, a part with a symmetrical trapezium shape is formed whereby the median part is closed with a plate 19.

The plates 18 and 19 extend to above the upper edge of the tank 10 and form a so-called channel 22 which is an extension of the channel 23 formed by the lower part 13 and the bottom part 14. A horizontal channel part 20 is connected herewith near the upper end of the plate 19 with a rectangular cross section in the cross direction.

In the channels 23, 22 et 20 a conveyor belt 25 is mounted which extends on a number of guiding rolls 30, 31, 32, 33, 34 and 35 and consequently follows these channels, whereby one of these rolls can be driven by non shown means. The rolls 30-35 are rotationally mounted in the walls 64, 65 of the tank. Multiple backing rolls 36 may be still mounted between the rolls. An endless belt 37 is arranged around the rolls 30-35. In a preferred embodiment, this belt 37 is provided on one side with projecting parts 38, which are preferably paddle-shaped, i.e. they stand diagonally from the upper surface of the belt and have a somewhat concave shape, seen in the direction perpendicular to the belt.

In the median part 12, two pipes 40, 41 extend in the longitudinal direction, which can each be connected with a feeding source of compressed gas, for example air which is conveyed through a blower or similar. The pipes 40, 41 extend horizontally in the longitudinal direction of the tank 10 near the walls 62, 63 thereof.

In an open connexion with the pipe 40, a number of cross pipe elements 45 are arranged which extend in the same horizontal plane as the pipes 40, 41 and extend up to about three quarters of the tank 10 width in the direction of the pipe 41. The pipe elements 45 have a closed free end, but are each provided with a number of vent ports for the conveyed gas.

The pipe 41 is connected in the same manner with a number of pipe elements 46 which also extend on approximately three quarters of the tank 10 width in the direction of the pipe 40. This is effected in such a way that, seen in the longitudinal direction of the 10, a pipe element 46 extend between each pair of neighbouring pipe elements 45 and vice versa.

A valve system is located in the feeding system for the gas leading to the pipes 40 and 41, whereby the gas feeding to the pipe 40 can be controlled independently from the gas feeding to the pipe 41. This way the gas feeding to both pipes 40, 41 may be performed simultaneously or alternately, this means for a determined period of time to the pipe 40 and subsequently for a determined period of time to the pipe 41, etc. In the alternate working, feeding to both pipes can also be carried out partially simultaneously. The device works as follows.

Once the tank 10 has been filled with a washing liquid, for example, water, the products to be washed, for example, potatoes, are conveyed near the end 16. Feeding may be performed continuously or semi- continuously through conveyor belts (not shown) or could be done by loading, for example by using a fork lift truck or a bulldozer. The feeding of gas to the pipes 40 and/or 41 is activated, whereby gas bubbles appear in the washing liquid so that some kind of a bubble bath is created, allowing the products to be washed very efficiently.

Due to the mounting of the pipe elements 40, 41, so-called gas bubble screens are formed in the tank at the level where washing is performed efficiently. On the other hand, these screens form a barrier for a further feeding of products in the tank 10.

When gas feeding to the pipes 40, 41 is done alternately, each time a determined amount of products is given the opportunity to move further to the next active bubble screen. By controlling the frequency of the alternate steps, the dwelling time and the feeding speed for the products may thereby be set, taking into account the nature of the products and the fouling degree .

As soon as a product is conveyed this way from the end 16 up to the vicinity of the end 17, it is taken over there by the conveyor belt 36, which is driven in the direction of the arrow A and consequently removed from the washing liquid. With the conveyor belt 36, the product is moved up to the channel 20, where it is unloaded, for example, in a container located hereunder . Near the end 17, a standpipe 55 is arranged, which is in open connexion with the channel 22 somewhat under the level of the upper edge of the tank 36, whereby the washing liquid level is maintained in the tank 36.

The standpipe 55 discharges on the other hand into a pipe 56 which is connected on the one hand with the bottom part 14 of the tank nearby the end part 17 by means of which the impurities to be removed can be discharged. The other end of the pipe 56 is linked to a non shown device for treating the contaminated washing liquid, for example, a decantation tank, after what the washing liquid is recycled back.

Using a belt 36 with projecting parts 38 having a recycling part near the bottom part 14 ensures that enough turbulence is created so as to prevent the impurities from easily decanting and can consequently be more easily discharged through the pipe 56.

On the other hand, it is possible, by reversing the motion direction of the belt 36, to have it work temporarily as a scraper, whereby the decanted impurities can be efficiently conveyed in the direction of the pipe 56.

Claims

1. A device for washing objects, more particularly agricultural products, such as bulbs or tubers, including a reservoir with a washing liquid, means for conveying agricultural products close to one end of said reservoir, and means for discharging agricultural products from another end of said reservoir, characterized in that means are present near the bottom of the reservoir for conveying and blowing a gas into the reservoir.

2. A device according to claim 1, characterized in that the air blowing means are preferably arranged in such a way that a number of vertical zones with air bubbles are formed that are arranged behind one another between the feeding end and the discharging end and the gas transportation to the independent vertical zones is controlled in such a way that each time only one of two successive zones is activated.

3. A device according to claim 2, characterized in that two gas feeding systems are arranged and, seen from the feeding end, the zones with even numbers are connected with the first conveying system and the zones with odd numbers are connected with the second conveying system, and the conveying systems can be activated alternately.

4. A device according to any of the preceding claims, characterized in that the bottom of the reservoir is provided with a flow pipe extending from the feeding end to the discharging end.

5. A device according to any of the preceding claims, characterized in that an endless conveyor belt extending on the one hand on the bottom of the reservoir and nearby the discharging end extends over the edge of the reservoir.

6. A device according to claim 4, characterized in that the conveyor belt is provided with elements oriented substantially perpendicularly to the conveyor belt.

7. A device according to claim 5, characterized in that the elements are paddled-shaped.