EP1860391A2

EP1860391A2 - Refrigerating applicance with sanitization device

Info

Publication number: EP1860391A2
Application number: EP20070010123
Authority: EP
Inventors: Giancarlo Pertegato; Daniel Philippe Mertens
Original assignee: Mertens Daniel; Stefani Daniele
Current assignee: Mertens Daniel; Stefani Daniele
Priority date: 2006-05-23
Filing date: 2007-05-22
Publication date: 2007-11-28
Also published as: ITPD20060205A1

Abstract

Refrigerating appliance with a sanitization device (20) comprising ventilation means (11) for producing an air flow inside the refrigerator compartment (4), intercepted by an active electrostatic filter (17) able to introduce a quantity of ozone capable of producing, together with a quantity of negative and/or positive charges produced by ionization means (18), a mixture having a microbicidal sanitizing action.

Description

Field of application

The present invention concerns a refrigerating appliance with sanitization device.
The refrigerating appliance in question is intended to be used advantageously for containing foodstuffs of any kind and is therefore classifiable within the industrial sector relating to the production of electric household appliances, cabinets and counters of the refrigerating type provided with devices for sanitizing the internal compartment including the surfaces which delimit it and, therefore, where necessary, also the products contained inside it.

Background art

On the market there are various known models of refrigerating appliances which are designed to improve the conservation of the products by producing electrostatic charges which are transported by an air flow in contact with the surfaces on which they exert their sanitizing effect.
For example, the patent JP 2005-134075 envisages deodorizing and sterilizing the environment of a refrigerating appliance by means of an ion generator and a fan which are both fixed to the inner upper wall of the storage compartment of the refrigerating appliance. According to this design the fan sucks in via a front opening an air flow and then, once it has been enriched with the electrostatic charges produced by the ion generator, it directs it towards the inside of the compartment to be sanitized via a discharge opening situated in the rear wall of the appliance.
This solution and other similar solutions already present on the market have in practice proved to be not devoid of drawbacks, having obvious functional limitations and major design problems.
The main drawback of these designs consists in the poor efficiency of the sanitizing action produced which is exclusively dependent upon the behaviour of the charges conveyed by the air flow. It has been possible to establish that the charges produced are quickly neutralized by the surfaces delimiting the compartment of the appliance such that they lose their sanitizing properties. This is mainly due to the fact that the internal walls of the refrigerating appliance are made of dielectric material which is easily charged with static electricity and which repels the charges produced or neutralizes the further production thereof without allowing a correct distribution of the said charges over the surfaces of the compartment to be sanitized.
Detailed research carried out by the present proprietors have shown that the sanitizing action of an ionized air flow has a microbicidal effect only on some micro-organisms and become less efficient with an increase in the relative humidity of the air or upon reaching values which may often be found in refrigerators.
The research carried in Japan by Yasuhiro Tanimura, Junji Hirotsuji and Takao Yamayoshi, published in 1999 in the "JOURNAL OF ANTIBACTERIAL AND ANTIFUNGAL AGENTS", and by the present applicants have shown that a mixture of gases with positive and negative charges has surprising microbicidal effects if combined with low concentrations of ozone.
This research has therefore highlighted a synergic effect due to the combined action of positive and/or negative ions with a small quantity of ozone, allowing the formation of an anti-microbial mixture with an action much greater than the action which can be attributed to the individual components.
This research has been applied in practice substantially only in the sector of systems for sanitizing living premises, while technical problems have hitherto prevented the application thereof in the sector of electric household appliances and in particular in the sector of refrigerators.

Disclosure of the invention

In this situation, the main object of the present invention is therefore to eliminate the drawbacks of the solutions of the known type mentioned above, by providing a refrigerating appliance with a sanitization device which allows sanitization of the internal compartment thereof, improving the conservation of the foodstuffs which can be kept inside it.
Another object of the present invention is to provide a refrigerating appliance, the sanitization device of which is perfectly efficient also where walls made of dielectric material are present.
A further object of the present invention is to provide a refrigerating appliance which is safe and operationally entirely reliable.

Brief description of the drawings

The technical features of the invention, in accordance with the abovementioned objects may be clearly determined from the contents of the claims indicated below and the advantages thereof will emerge more clearly from the detailed description which follows, provided with reference to the accompanying drawings, which show a purely exemplary and non-limiting example of embodiment thereof in which:

Fig. 1 shows a front view of an embodiment of the refrigerating appliance with the sanitization device according to the present invention with some parts removed so that other parts may be seen more clearly;
Figs. 2 and 3 show two cross-sectioned side views of the refrigerator according to Fig. 1;
Fig. 4 shows an enlarged detail of the refrigerating appliance, relating to the sanitization device alone;
Figs. 5a and 5b show two details of the sanitization device of the preceding figures, relating to the electrodes for generating electric charges;
Fig. 6 shows a schematic view of the refrigerating appliance with the sanitization device according to the present invention.

Detailed description of a preferred example of embodiment

With reference to the accompanying drawings 1 denotes in its entirety the refrigerating appliance according to the present invention.
It includes a furniture unit, the form of which is not the subject of a specific claim. The furniture unit in question may advantageously be made in any style and of any material, in particular of the type commonly used for the manufacture of electric household appliances or refrigerated cabinets and counters.
More particularly the refrigerating appliance may consist both of a door-type refrigerator as well as a food storage buffet with suitable display shelves and a refrigerated food display cabinet. Below reference will be made, with the aid of the accompanying figures, to a door-type refrigerating appliance, for example of the type for domestic use, it being understood, however, that it may also consist of the other abovementioned appliances without thereby departing from the scope of protection of the present patent.
The furniture unit comprises in particular a support structure - denoted generically by 2 - resting on the ground for example by means of legs and defining internally a storage compartment 4. The latter is intended to contain any type of foodstuff which requires refrigeration for correct conservation over time and in particular for storing products for domestic use such as meat, cheese, drinks, fruit and vegetables or similar products which, as is known, require a carefully controlled conservation temperature.
In accordance with the example considered in the accompanying figures, the refrigerating appliance 1 consists of a machine for domestic use provided at the bottom with a freezing section and at the top with an actual refrigerating section. Obviously, without departing from the scope of protection of the present invention, the term "refrigerating appliance" must be understood as meaning not only a refrigerator for domestic use in the conventional form, shown by way of example in the accompanying figures, but also any other type of refrigerator for domestic or industrial use and of any shape or size.
With reference to the example of the accompanying drawings, the inside of the compartment 4 is provided, in a manner which is entirely conventional per se, with guides 5 supporting shelves 3, only some of which have been shown, for storing the food which is to be preserved. In the case of an appliance consisting of a refrigerated display cabinet or buffet the shelves will have the function of displaying the products.
The refrigerating appliance 1 also comprises a refrigerating device which is mechanically and functionally connected to the compartment, for refrigerating the products contained inside it.
The refrigerating device may for example be formed, in an entirely conventional manner, by evaporation coils which are arranged inside the walls or by a compressor and by a condenser which are housed on the support structure 2 in the bottom and rear part of the refrigerating appliance.
The compartment 4 has a substantially box-shaped form and is delimited by insulating walls, comprising two side walls 6 and 7, a bottom 8, a rear wall 9, an upper wall 10 and one or more doors which are pivotably mounted on hinges (not shown in the figures). All of the abovementioned walls and doors are insulated or thermally isolated so as to preserve the products without loss of heat to the external environment. For this purpose, they preferably consist of plastics which behave in terms of electrical properties in the manner of dielectric materials which are able to absorb with extreme ease electrostatic charges.
According to the present invention, the refrigerating appliance is provided with a sanitization device 20 which is fixed onto the upper wall 10 of the compartment 4, underneath a shaped cover 12.
It comprises ventilation means 11 able to produce an air flow and cause it to circulate inside the compartment 4 and for example consisting simply of a low-power electric motor connected to a propeller or a centrifugal fan.
Intake and emission of air is performed via openings bounded by the cover 12 and denoted by the numbers 14 and 15, respectively, or by means of frontal direct flow towards the end wall 9. Alternatively, a duct 13 is provided adjacent to the rear wall 9 of the compartment 4 and connected directly to the cover 12 (or protective housing) so as to convey the air flow by means of diffusers 16 at different heights, for example situated opposite the shelves 3.
According to the invention an electrostatic filter 17 is also provided, being arranged so as to intercept the air flow in order to capture most of the particles and the micro-organisms present in the air sucked in together with the dust. At the same time, the electrostatic filter 17 is able to introduce inside the said air flow a quantity of ozone, which is of a limited amount, so as to avoid in any case exceeding the levels which are permitted by the existing regulations, for example an amount advantageously less than 0.2 ppm.
In accordance with a preferred solution of the present invention able to allow miniaturization of the components for practical installation of the sanitization device 20 in refrigerating appliances 1 of any size, the electrostatic filter 17 consists of a positive ionization section and a capturing section, the latter being formed by means of an alternating arrangement of positively charged earth plates arranged facing each other, or a capturing section formed by an alternating arrangement of positively or negatively charged earth plates arranged facing each other.
Ionization means 18 are also envisaged for introducing a concentration of positive and/or negative charges into the air flow, able to produce, together with the ozone, a mixture having a microbicidal sanitizing action.
The air treated by the ventilation means 11 and sucked in by the volume of the compartment 4 is therefore subjected to the microbicidal and filtering action of the electrostatic filter 17 and only then is introduced again into the compartment 4, preferably via the diffusers 16 so as to produce the circulation of an air flow which is able to convey the microbicidal mixture such that it passes over the surfaces of the walls and, if present, the products contained inside the compartment 4, sanitizing them. Therefore, advantageously the ventilation means treat exclusively the air present inside the compartment causing the flow to pass over the surfaces of the walls and, where present, the products contained inside the compartment. This may substantially also occur in the case of a buffet owing to the stratification of air which occurs inside it and even though the compartment is not physically closed off from the external environment.
Advantageously, the ionization means comprise electrodes of different polarity consisting of charge emitters situated at a distance from each other with preferably first emitters 18A, for example for negative charges, arranged on the first side wall 6 of the compartment 4 and second emitters 18B, for example for positive charges, which are arranged on the second side wall 7 of the compartment 4 facing the first wall.
The presence of electrodes with a different polarity solves the problems relating to neutralization of the production of charges due to charging of the dielectric surfaces of the walls, allowing a uniform distribution and flow of the charges emitted in the air flow so as to flow over the surfaces of the walls. In the case of metal surfaces, on the other hand, since they are conductive, there are no problems of neutralization of the charges emitted since in this case said charges emitted are discharged to earth.
Preferably, the emitters are arranged opposite the diffusers 16, whereas, if the distribution duct 13 is not present, the ionization means may be arranged along the side walls and/or in the delivery air flow as schematically indicated by the numbers 18 A, B and C in Figure 6.
The device 20 is suitable for being installed also in refrigerators of the conventional type and advantageously both those of the type with a duct 13 for circulating air so as to prevent condensation (so-called "no-frost" fridges) and those which do not have this duct. Preferably, in the case of the former the emitters 18 will be arranged opposite the diffusers 16, while in the case of the latter they are arranged in the region of the emission opening 15 or in both cases in the opposite walls. In this latter case it may also be envisaged providing first emitters in the region of the first emission opening and second emitters along one or both the walls.
The emission of charges by the electrodes is advantageously performed by taking advantage of the corona effect of the emitters 18 which for this purpose are suitably shaped with a pointed form and preferably are printed in circuits provided on strip-like supports which are mounted on the side walls of the compartment 4. Alternatively, only one emitter will have a pointed shape while the other emitter will have a plate-like form simply in order to attract the charges produced by the other pointed emitter.
The microbicidal mixture causes a reduction in the bacterial and microbial content in general, not only in the treated air of the volume of the compartment 4 but also over all the surfaces with which it comes into contact.
Advantageously, the refrigerating appliance according to the present invention has proved to be surprisingly effective in preventing the development of microbial species which are of interest from a hygienic/sanitary point of view and which may contaminate the food preserved in the compartment 4. Numerous comparative tests carried out on refrigerating appliances of the known type and on refrigerating appliances according to the invention have, for example, shown that there is a surprising reduction, even after only a few hours, of the micro-organism cells (for example surfaces populated with the micro-organisms "Listeria innocua" and "Escherichia coli" were tested) only in refrigerators with the sanitization device according to the invention. This reduction proved to be of the order of two logarithms already after 24 hours.
The utility of the refrigerating appliance 1 according to the invention lies in the capacity of the sanitization device 20 installed on it to create an environment which is constantly sanitized, preventing contamination between contact surfaces and food.
This thus reduces considerably the risk of contamination of the food which may accidentally come into contact with condensate and with surfaces of the compartment 4 on which, as is known, the microbial species are often able to proliferate easily.
Numerous sensorial analyses carried out on different food such as, for example, cheese, meat and vegetables, showed that the conservation technique due to use of the refrigerating appliance according to the present invention does not influence in any way the organoleptic properties of the preserved food.
Similarly, the results of colour definition tests confirm the outcome of the sensorial tests, namely that no differences were encountered between the samples stored in a normal refrigerating appliance and the refrigerating appliance according to the present invention.
The invention therefore achieves the predefined objects.
Obviously, it may assume, in its practical embodiment, also forms and configurations which are different from that illustrated above without thereby departing from the present scope of protection.
Moreover, all the details may be replaced by technically equivalent elements, and the dimensions, the forms and materials used may be of any nature according to requirements.

Claims

Refrigerating appliance with sanitization device comprising:
- a support structure provided with walls able to delimit a compartment for containing foodstuffs or products of varying nature, said compartment being accessible via at least one opening;

- a refrigeration device mounted on said support structure and mechanically and functionally connected to said compartment;
characterized in that said sanitization device comprises:
- ventilation means able to produce an air flow able to circulate inside said compartment;

- an active electrostatic filter arranged so as to intercept said air flow and able to introduce a quantity of ozone inside the latter;

- ionization means for introducing a quantity of negative and/or positive charges into said air flow, able to produce together with said quantity of ozone a mixture having a microbicidal sanitizing action.
Refrigerating appliance according to Claim 1, characterized in that said ionization means comprise electrodes with a different polarity.
Refrigerating appliance according to Claim 2, characterized in that said electrodes with a different polarity consist of charge emitters which are situated in a position at a distance from each other.
Refrigerating appliance according to Claim 3, characterized in that at least one first emitter is arranged on a first side wall of the compartment of the refrigerator and in that at least one second emitter is arranged on a second side wall of the refrigerator situated opposite the first wall.
Refrigerating appliance according to Claim 1, characterized in that said sanitization device comprises at least one opening for sucking in the air flow from the compartment and at least one opening for emitting the air flow into the compartment.
Refrigerating appliance according to Claim 5, characterized in that it comprises a duct connected to said opening for emitting said air flow so as to convey said flow by means of diffusers into different positions of the refrigerator.
Refrigerating appliance according to Claim 1, characterized in that said duct is situated along the rear wall of said compartment with the diffusers arranged opposite storage shelves provided.
Refrigerating appliance according to Claims 4 and 7, characterized in that said emitters are arranged opposite said diffusers.
Refrigerating appliance according to Claim 5, characterized in that said ionization means are situated in the region of said opening for emitting the air flow and/or along said walls.
Refrigerating appliance according to Claim 2, characterized in that at least one of said electrodes with a different polarity consists of a charge emitter with a pointed or plate-like form, in particular printed in a strip-like circuit mounted on at least one side wall of said compartment.