The present invention relates to a device and a method for washing leafy vegetables.

Leafy vegetables such as salad, chard, spinach and the like have always been bought in heads or bunches.

Before consumption, the product needs to be separated leaf by leaf, the best leaves are selected, any damaged ones are disposed of, and the remaining ones are washed repeatedly to remove any remains of soil or chemical agents used during cultivation.

Finally, the leaves washed and sterilised with suitable solutions in powder or liquids for domestic use, must be dried before use or, if not eaten immediately, before being stored in the refrigerator.

In order to accommodate the needs of normal families who increasingly have less time at their disposal, particularly to dedicate to cooking, mass retail has been providing the same vegetables for a number of years now to customers, defined as 4 ^th range products, sold in closed bags with leaves that have already been separated, selected, washed, disinfected and dried and that can be eaten straight away without any further treatments.

In the production process, after separating the leaves and selecting the best ones to be sold, the vegetables are washed carefully. The washing techniques envisage not only washing in water, but also the disinfection of the product to reduce the bacterial load normally present and thus increase the shelf life and freshness of the product.

The leaves are transferred into a hopper together with water and from there flow along a washing channel.

Chemical agents such as ozone, which is one of the few chemical agents allowed as a food disinfectant, are added to the washing water.

Since both the hopper and the channel are open at the top there may be some dispersion of ozone into the work environment, with potential risks for the operators' health. In fact, ozone concentrations in the work environment are established by precise legislation.

Furthermore, washing with the top open makes the final result less effective.

It is an object of the present invention to provide a device and a method for washing leafy vegetables that overcomes the drawbacks of the prior art.

It is also an object of the invention to provide a device and a method for washing leafy vegetables that allows the 4 ^th range product to be washed and disinfected guaranteeing a healthy work environment.

Furthermore, the object of the present invention is to provide a device and a method for washing leafy vegetables that maximises and optimises the mixing of ozone into water.

Finally, an object of the present invention is to provide a device and a method for washing leafy vegetables that maximises the washing effect guaranteeing an optimal result in terms of washing and disinfection of the 4 ^th range product.

These and other objects are substantially achieved by a device and a method for washing leafy vegetables according to the description given in one or more of the attached claims.

Further characteristics and advantages will more fully emerge from the detailed description of a preferred and not exclusive embodiment of a device and a method for washing leafy vegetables according to the present invention.

This description is provided with reference to the accompanying figures, which are also provided purely by way of illustrative and thus non-limiting example, of which:

- Figure 1 is a first perspective view of a device for washing leafy vegetables according to the preferred embodiment of the present invention; - Figure 2 is a second perspective view of a device for washing leafy vegetables according to the preferred embodiment of the present invention;

- Figure 3 is a schematic view of a detail of the device of Figures 1 and 2. The device for washing leafy vegetables has been indicated in its entirety in the appended figures with reference number 1 .

This device 1 comprises a vegetable loading station 2 for vegetables to be washed P and a vegetable unloading station 3.

A washing and transport channel 4 places the loading station 2 and the unloading station 3 in communication, transporting the vegetables P from the first to the second station.

The washing and transport channel 4 comprises a collection tank 5, or a hopper, and a tube 6 inside of which the vegetables P are washed and transported to the loading station 3.

The tank 5 has a surface exposed to the surrounding environment which remains closed during operation. The tube 6 is a closed conduit which extends from the tank 5 to the unloading station 3.

A conveyor belt 7 feeds the leafy vegetables to the loading station 2, in particular to the collection tank 5. Likewise, another conveyor belt 8 receives the washed leafy vegetables P at the outlet from the tube 6 and appropriately separated from the washing liquid.

The leafy vegetables are washed using a washing liquid which fills the washing and transport channel 4.

In particular, the washing liquid is, preferably, water with added ozone. The device 1 further comprises dispensing means 9 for dispensing the washing liquid, said dispensing means 9 being adapted to fill the channel 4, particularly the collection tank 5.

Such dispensing means 9 are in fluid connection with a mixing tank 10 within which ozone is added to the washing liquid before being poured into the washing and transport channel 4.

The mixing tank 10 comprises an inlet conduit 1 1 through which water enters, an outlet conduit 12 through which the washing liquid is sent to the dispensing means 9.

The water coming into the tank 10 is filtered through a first filter 20 located along the inlet conduit 1 1 , immediately upstream of the tank 10.

A second filter 21 is located downstream of the washing path, in particular downstream of the tube 6 in proximity to the unloading station 3 after the washed leafy vegetables have been separated from the washing liquid.

This second filter 21 collects the remains of any leaves still in the liquid after separation from the washed vegetables.

The first filter 20 has a smaller mesh than the second filter 21 since it must effectively prevent the entry of any solid substance into the tank.

The tank 10 further comprises an ozonisation circuit for transforming the water at the inlet to the tank 10 into washing liquid at the outlet of tank.

The ozonisation circuit 13 comprises a pump 14, which takes the filtered water at the inlet to the tank 10, an ozone ejector 15, which adds ozone to the water taken, and an injector 16 which reintroduces the water with ozone into the tank 10.

The mixing of the water in the tank 10 allows optimal dissolution of ozone in water so as to minimise any dispersion of ozone into the atmosphere. An ozone removal system 17 is located above the tank to aspirate any minimal dispersions of ozone that may arise in the surrounding air.

Above the collection tank 5 and above the unloading station 3, there are respective suction hoods 18 and 19 provided for the suctioning the quantities of ozone that may be released from the water when it is exposed to the surrounding environment.

The suction hood 18 located above the collection tank 5 is advantageously a cover 18' which keeps the exposed surface of the tank 5 closed, minimising the dispersion of ozone into the surrounding environment.

The cover 18' is mobile between an operative closed position, in which it is sealed onto the tank, and a non-operative position in which it is open to allow inspection of the tank 5. The cover 18' has a through opening 25 to allow insertion of the leafy vegetables to be washed in the tank 5, when the cover 18' is in the operative closed position on the tank 5.

At the through opening 25 there is an ozone suction conduit 18" adapted to remove the ozone which is accidentally released into the air.

The collection tank 5 may preferably be of an elongated shape, but it could also be of different shapes or even be a simple hopper.

The dispensing means 9 are advantageously arranged along one side of the tank 5, preferably along the shortest one, so that the jet of liquid introduced into the tank 5 on one side pushes the leaves towards the opposite side, at which the inlet 6a of the washing tube 6 is located.

Preferably, along the washing tube 6 there is an ultrasound system 22 and/or a UV ray disinfectant system, both provided to increase the washing effect for the vegetables.

When the vegetable leaves are in the proximity of the unloading station 3, they are separated from the washing liquid and conveyed to a subsequent processing station. Appropriately filtered and with any remains of leaves cleaned out, the washing liquid is reintroduced into the washing circuit. On that point, the device 1 also comprises a conduit 24 for recirculating the water after separation from the vegetables, to reintroduce the appropriately filtered water into the mixing tank 1 0.

The method for washing leafy vegetables therefore comprises the steps of feeding the selected leaves, using a conveyor belt 7, to the washing and transport channel 4 which comprises the collection tank 5 and the washing and transport tube 6. The most effective washing is performed inside the closed path defined by the tube 6.

The washing liquid, comprised of ozonised water, is introduced into the tank by specific dispensing means 9 so as to create a current able to push and drag the leaves towards the inlet of the tube 6. The continuous flow of the washing liquid inside the tank 5 promotes the movement of the flow of leaves inside the washing tube 6, up to the outlet of the tube 6 at the unloading station 3.

The method comprises the further step of ozonising the water used for washing, then adding ozone inside the tank 10 equipped with a suitable ozoniser. This procedure, which envisages the nebulisation of water and ozone in the tank, improves the mixing the ozone in the water.

Before being introduced into the tank and after separation from the washed vegetable leaves, the water is filtered.

Along the tube ultrasound and/or UV rays may be advantageously used to boost the washing effect.

The washing inside the tube, therefore in a closed system, allows the mixing effect of the ozone with the water to be maximised as well as increasing the contact of the product to be washed with the washing liquid.

Furthermore, the closed tube transport system, as well as the presence of suction hoods at the parts where the washing liquid is exposed to the surrounding environment, minimises the dispersion of ozone into the work environment.