FR2813878A1 - Water recycling apparatus for fruit, vegetable or cereal processing installation has circuit including filters and injection devices for sterilizing product - Google Patents

Abstract

A water recycling apparatus has a circuit (6) recycling water to an upstream part of an industrial installation (2). The circuit includes filter(s) and devices for injecting a sterilizing product. The combined volume of the installation and the circuit is chosen so that the sterilizing product is effective. An Independent claim is also included for a machine using water for transporting fruit, vegetables and/or cereals, and including the above apparatus.

Description

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The present invention relates to a device for recycling water in the industrial field. The industries more particularly targeted by the present invention are the industries related to the agricultural and agro-food fields.

The present invention is particularly suitable for recycling water used for the transport of fruit, vegetables or cereals. Usually, fruit, vegetable or cereal grading machines consume hydraulic transport water for: emptying pallet boxes, washing fruit, vegetables or cereals, sorting fruit, vegetables or cereals, calibrating those - storage after calibration, washing of pallet boxes and finishing packaging.

The water used for this transport is polluted by the pallet boxes which are more or less soiled with dirt, foreign bodies such as twigs, leaves, papers, etc. In addition, the fruits and vegetables themselves, depending of their maturity, the phytosanitary products used, their time of storage or conservation, the conditioning period more or less advanced in the season also pollute the water.

The pollution of these transport waters is both insoluble and soluble pollution. Insoluble pollution is of mineral origin, for example presence of sands and gravels, silts, etc ... and also of organic origin by the presence of branches, leaves, rots, etc ... Soluble pollution is essentially d organic origin and is due to the presence of tannins, pesticides, microorganisms, bacteria, fungi, etc ...

For several years, regulations have required the use of quality water for the transport of fruit, vegetables and cereals. In the fruit and vegetable sector, controlling microbiological risks essentially involves controlling the quality of the water used at the various stages of packaging and keeping the packaging clean. In the case of the use of water from the distribution network, the problem of physico-chemical and bacteriological quality does not arise at the outset. However, the water used gets dirty very quickly.

Currently, the quality of the water used is guaranteed by use at

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 quality water and frequent emptying of the hydraulic transport and washing circuit.

This solution has two drawbacks. The first is that the quality of water degrades very quickly. It is impossible to guarantee that fruits and vegetables, or possibly cereals, are always in contact with water of good bacteriological quality. The other problem is the cost price of this solution. Indeed, frequent emptying results in very high water consumption. In fact, the fluid flow rates generally observed are of the order of several hundred m3 per hour.

The present invention firstly aims to provide a device for having along the different stages a water having a good physicochemical and bacteriological quality. Advantageously, the proposed device will reduce water consumption.

To this end, it proposes a device for recycling water intended for an industrial installation which, according to the invention, comprises, bypassing this installation, a circuit withdrawing water downstream to reintroduce it upstream, the circuit comprising at least one device allowing the filtration of the derived water as well as means for injecting a sterilizing product, the volume of the circuit and of the installation with which it is associated serving as the volume in which the product remains before being effective and to have a sterilizing action.

This recycling device makes it possible, on the one hand, to filter the water and, on the other hand, to make it sterilizing. The quantity of sterilizing product injected is of course adapted to the specific needs of each installation, depending on the pollution of the water by external agents. The presence of sterilizing product in the installation and almost all the associated derivative circuit, allows to have a prolonged sterilizing action and therefore good quality water throughout the time it is used.

In one embodiment, the means for injecting a sterilizing product are arranged downstream of the filtration device, at least one in number. The injected product is in this case put into the circuit just before returning to the installation with which it is associated.

Additional means for injecting a sterilizing product are

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 for example also arranged so as to be able to inject such a product upstream of the filtration device at least one in number. They can be found, for example, before the filtration device (s) mentioned above. This allows sterilization of the fluid at the same time as its filtration. Advantageously, the circuit includes at least one screen cleaning filter with automatic unclogging arranged upstream of the filtration device. A "pre-filtration" is carried out by this screen filter which has a breaking capacity adapted to the installation and to the insoluble pollution encountered.

As a variant, provision may be made for means for sterilization by ultraviolet rays at least upstream or downstream of the filtration device. The fluid is then sterilized before or after being filtered.

In a first embodiment, a first filtration device is constituted by a sand filter. A second filtration device constituted by an active carbon filter can also be provided. In known manner, the first filtration device makes it possible to retain the insoluble or insoluble mineral and organic materials by a preliminary treatment while the second filtration device adsorbs the soluble organic materials and the residual free chlorine.

The sterilizing product injected by the sterilizing product injection device (s) is preferably chlorine dioxide. This product is not very oxidizing. It is therefore not aggressive for the pipes and other components of the installation and of the recycling device. In addition, this product has no odor and does not give an unpleasant taste to water.

In order to best adjust the quantity of sterilizing product injected, a device making it possible to control the content of sterilizing product in the water is advantageously arranged at the inlet of the bypass circuit. This control device is of course connected directly or indirectly to the device (s) for injecting sterilizing product to achieve the correct dosage of product. Flowmeters are also preferably provided for measuring the fluid flow and in order to be able, according to the information measured, to adapt the quantity of product to be injected.

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 To achieve better filtration and sterilization of the fluid passing through the derived recycling circuit, the latter preferably also includes means allowing the injection, upstream of the filtration device at least one in number, of adjuvant products and / or coagulants and / or flocculants.

The present invention also relates to a machine using water as a transport vector for fruit and / or vegetables and / or cereals, characterized in that it is equipped with a recycling device as described above. This machine is for example a calibrating machine. The recycling device can be common to several machines (calibrating machines for example). It can recycle all or part of the fluid flow used by the machine (s) with which it is associated.

The description which follows will allow, with reference to the appended drawing, to better understand the aims and advantages of the invention. It is clear that this description is given only by way of example and is not limiting.

The single figure is a schematic overview of a recycling device according to the invention.

This figure shows a machine using water as a transport vector for fruit, vegetables or cereals. It is for example a machine to calibrate 2.

At the outlet of this calibrating machine, water is pumped using a pump 4 in order to be treated before being reinjected into the calibrating machine 2. The water thus pumped passes through a circuit of lead 6 in which it undergoes several treatments. To this end, the circuit 6 comprises in particular a screen filter 8, a sand filter 10 and an active carbon filter 12. In addition, means allowing the injection of products into the circuit are provided between the screen filter 8 and the sand filter 10 and downstream of the active carbon filter 12.

In the embodiment shown, all the water circulating in the calibrating machine 2 is pumped to the bypass circuit 6. Here, complete recycling of the water circulating in the calibrating machine 2. The use of the pump 4 can be optional when the installation allows the passage of water by gravity from the machine to be calibrated 2 to the bypass circuit 6.

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 The bypass circuit 6 includes numerous valves 14 and automatic valves 16. These valves and their functions will not be described in detail here because they are known to those skilled in the art. The representation in the single figure of these valves and automatic valves is sufficient to fully understand the operation of the installation.

The first treatment undergone by the water is the passage through the screen filter 8. Screening the water makes it possible to carry out a primary filtration operation. The screen filter comprises a filtering medium constituted by a metallic fabric having a horizontal tubular shape. This fabric has a breaking capacity less than or equal to 50 km, for example 20 μm. Water flows through the filter media from top to bottom on generators of the tubular form. The suspended matter in the water is trapped on the filter medium inside the tubular form.

Automatic unclogging of the broiler is planned. This unclogging is done on the high generators of the tubular form by cleaning with water or air under pressure. It is carried out from the outside of the tubular form and removes trapped clogged materials. These are collected in a trough judiciously placed and arranged inside the tubular form. An automatic extraction system can be provided at this trough.

After passing through the screen filter 8, the water is evacuated by gravity before being taken up by a pumping system comprising a pump 18. After each pump 4, 18, a flow meter 20 is provided for measuring the quantity of water pumped. .

After the second flow meter 20, there is an injection device 22 intended to introduce a coagulating and / or sterilizing product into the screened water. The injection of these products tends to insolubilize insolubilizable organic matter and colloidal mineral forms. It also allows sterilization of the medium in the bacteriological sense of the term and of the drinking water standards in force. The products used can be of organic or mineral origin. Mention may be made, for example, of: metal salts, chlorine or chlorinated compounds or derivatives of chlorine, oxidants of all forms or natures, etc. A preferred embodiment provides for the injection of

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 chlorine which is a weak oxidizing product, which does not give taste to water and does not smell.

The injected sterilizing product requires a residence time in the water to act and block dead microorganisms. Here, the sterilizing product is injected soon after the water enters the bypass circuit. Thus the product will act during the treatment of the water and there is no need to provide a tank in which the water rests to let the product act. The primary and derivative circuits are of large volume and are used here as contact volume.

In the present embodiment which subsequently provides for a second injection of sterilizing product, it is for example possible here to replace the injection of sterilizing product by sterilization carried out in another way. There are for this electrical, magnetic, electromagnetic, etc. processes, and it is also possible to use ultraviolet.

The water, still under pressure thanks to the pump 18, is introduced into the sand filter 10. The filter material and the filtering materials are chosen so that they resist without damage to the products which will be in contact with them. They will, for example, be synthetic or composite materials and calibrated flint of suitable particle size. In normal operation, the water passes through the sand filter 10 from top to bottom. The filtering medium retains mineral and organic materials, insoluble or insolubilized by the injection of coagulating and / or sterilizing products.

The amount of material retained in the sand filter 10 is a function of the volume and the particle size of the filter medium. In one embodiment, a layer of filter media may be provided with a height of between 1 and 1.2 m. The speed of passage through the filter 10 is for example between 8 and 15 m3 / h.

The clogging of the sand filter 10 is determined by a differential pressure measurement between the inlet and the outlet of the sand filter 10. When this pressure difference exceeds a predetermined threshold, a filter washing operation can be initiated manually or automatically. . It is also possible to provide washing operations for the filter 10 regularly scheduled over time.

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 The filter is washed by passing fluid from bottom to top, while generally the fluid passes from top to bottom. The water used for the washing operation, contaminated with clogging particles, is discharged from the system. An additional fluid is added to compensate for this evacuation. It has an additional dilution effect on the system.

After this first filtration in the sand filter 10, the filtered fluid is introduced, still under pressure, into the active carbon filter 12. The dimensional characteristics of this active carbon filter 12 are preferably identical to those of the sand filter 10 .

The active carbon used in this filter adsorbs soluble organic matter and all of the residual free chlorine in the fluid. Once the active carbon used in this filter 12 is saturated, these are landfilled. Indeed, the characteristics of the active carbon used and of the adsorbed elements do not present any particular harmfulness and no particular treatment is therefore to be provided for their elimination.

At the outlet of the active carbon filter 12, a second injection device 24 is provided. At this level, sterilizing product is injected. Chlorine dioxide will also be used here, for example. The quantity of product injected here is sufficient to eradicate the new bacteria likely to be introduced into the circuit. The quantity of product injected is controlled by measuring the excess of sterilant. A device 26 is provided at the input of the bypass circuit 6, after the first flow meter 20, for measuring the quantity of sterilizing product present in the water. This information is used to dose the quantity of product to be injected into the circuit by the injection device 24. In the drawing, the device is located in front of the screen filter 8. However, in certain variant embodiments, this device 26 may be downstream of the screen filter 8.

At the entry of circuit 6, just before or after the device 26 for measuring sterilizing product, a pH meter 28 is placed to measure the pH of the water. This measurement is also used for metering the products at the injection devices 22 and 24.

The injection of sterilizing product by the injection device 24 makes the water leaving the bypass circuit 6 sterilizing. This water is sterilized by the first

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 injection device 22. Here too, it is unnecessary to provide a tank for the sterilizing product to act, which always requires a residence time. The primary and derived water circuits also serve here as tanks.

The bypass circuit 6 is described here in relation to a fruit grading machine 2. This bypass circuit could be used with another machine using water as a vector for hydraulic transport.

It is also possible to use a single branch circuit to recycle water from several machines such as the calibrating machine 2.

The bypass circuit described treats all the water leaving the machine to be calibrated 2 and reinjects it into this machine. It is possible to recycle only part of the water. One can for example consider recycling only half of the water leaving the calibrating machine 2, the other half of the water being reinjected into the calibrating machine without being recycled.

The recycling device as described above is original in the sense that the contact times which must be implemented to carry out sterilization or coagulation do not require any particular volume. It is the entire volume of the installation which is treated all or part of a recirculation flow which is used to let the sterilizing and / or coagulant products introduced into the water circuit act.

The use of a primary screen filter is also advantageous. This screen filter acts as a filter and has a breaking capacity less than or equal to 50 micrometers. The screen filter used is ergonomic because it is fully automatic in its unclogging and the expulsion of unclogging residues.

The device as described above allows significant gains to be made for its operator. In fact, water is recycled at a much lower cost than replacing it. In addition, thanks to the bacteriological quality of the water throughout the circuit, as well as in the machine with which it is associated, the fruits, vegetables or cereals transported rot less, which therefore allows better preservation of fruits, vegetables or cereals with a lower loss rate.

The scope of the present invention is not limited to the details of the embodiment above considered by way of nonlimiting example, but

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 on the contrary extends to modifications within the reach of ordinary skill in the art, within the scope of the claims below.

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Claims (11)

1. A device for recycling water intended for an industrial installation (2), characterized in that it comprises, bypassing this installation, a circuit (6) taking water downstream to reintroduce it upstream, and in that the circuit comprises at least one device (10, 12) allowing the filtration of the diverted water as well as means (22, 24) for injecting a sterilizing product, the volume of the circuit and of the installation to which it is associated serving volume in which the product remains before being effective and having a sterilizing action. 2. Recycling device according to claim 1, characterized in that means (24) for injecting a sterilizing product are arranged downstream of the filtration device (10, 12) at least one in number. 3. Recycling device according to claim 2, characterized in that complementary means for injecting (22) a sterilizing product are arranged so as to be able to inject such a product upstream of the filtration device (10, 12) to the number of at least one. 4. Recycling device according to one of claims 1 or 3, characterized in that the circuit (6) comprises a screen filter (8) disposed upstream of the filtration device (10, 12) at least one . 5. Recycling device according to one of claims 1 to 4, characterized in that means for sterilization by ultraviolet are provided. 6. Recycling device according to one of claims 1 to 5, characterized in that a first filtration device is constituted by a sand filter (10). 7. Recycling device according to claim 6, characterized in that it comprises a second filtration device constituted by an active carbon filter (12). 8. Recycling device according to one of claims 1 to 7, characterized in that the sterilizing product injected is chlorine dioxide. 9. Recycling device according to one of claims 1 to 8, characterized in that a device making it possible to control (26) the content of sterilizing product in the water is arranged upstream of the filtration device (10, 12) at least one. <Desc / Clms Page number 11>  10. Recycling device according to one of claims 1 to 9, characterized in that it also comprises means allowing injection (22), upstream of the filtration device (10, 12) at least in number one, adjuvants and / or coagulants and / or flocculants. 11. Machine (2) using water as a transport vector for fruit and / or vegetables and / or cereals, characterized in that it is equipped with a recycling device according to one of claims 1 to 10 .