GB2161718A

GB2161718A - Cooker hood

Info

Publication number: GB2161718A
Application number: GB08516759A
Authority: GB
Inventors: Udo Gruen
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-07-02
Filing date: 1985-07-02
Publication date: 1986-01-22
Also published as: IT1185147B; IT8521361A0; DE3424318A1; FR2568795A1; GB2161718B; FR2568795B3; GB8516759D0

Abstract

A cooker hood containing a grease-retaining filter (not shown) is provided with a device which is mounted on the underside of the intake and releases disinfectant into the airflow to prevent bacteria from accumulating on the filter. Various devices such as ozone generators are mentioned, but as shown the device comprises a perforated tray 2 enclosing a filter paper 5 impregnated with disinfectant such as amphoteric tenside. An upstream filter paper 3 prevents grease from reaching the paper 5 and includes a substance which changes colour to show that it has absorbed grease and consequently that the main filter in the hood has done so. Only a small fraction of the air flow to the hood passes through the device. <IMAGE>

Description

SPECIFICATION Vapour extractor hood The invention relates to a process for disinfecting a vapour extractor hood, more particularly a filter mat fitted in a vapour extractor hood above a filter plate and which filter cooking vapours, more particularly a filter mat which absorbs fat and oil, and the apparatus for carrying out such a process.

Vapour extractor hoods are used in particular in households and are intended, when operational, to remove the cooking vapours from the room, thereby protecting the room against saturation. For this purpose, the filter mats must have in particular a good capacity for retaining fatty and oily substances, but must still be easily penetrated by air. There are in fact filter mats which are capable of retaining quantities of oil and fat to an extent of up to approximately 600 g/m2. The disadvantage in this case is that the fire risk increases accordingly as a result of the large quantities of oil and fat which are collected. A further disadvantage is that the stored oil or fat is subject to continuous decay as a result of oxydation and hydrolysis.Although this decay is generally only noticeable in the form of a bad smell, the micro-biological decomposition which accompanies this decay can become a health risk owing to the formation of toxic substances. It should be borne in mind in this connection, that vapour extractor hoods of this type are generally arranged above the cooker, i.e. directly above the food which is to be cooked and which is intended for consumption.

The disadvantages described thus make it essential for filter mats of this type to be replaced whenever they are saturated to a particular degree with oil or fat, or when smaller quantities of oil and fat begin to decompose, possibly producing an unpleasant smell, or even toxic substances as a result of colonisation by bacteria and mould.

Various possibilities for indicating this point in time are already known. They are generally based on the principle that they indicate when the filter mats have reached the end of their capacity to retain, i.e. when they are saturated with oil and fat. According to the type of indicator which is used for this purpose, it can also be concluded from a particular discoloration that a large degree of microbic contamination has taken place. The filter mat must be replaced by this point in time at the latest, irrespective of the degree of saturation of the filter mat.

However, since in some makes the indicator can only be seen or interpreted with difficulty, the replacement of the filter mats often does not take place, which in addition to the increased fire risks leads to extremely unhygienic conditions, which may quite possibly lead to the toxicity not only of the entire air passages which are used by the vapour extractor hood, but also of air recirculated to the associated room.

In accordance with a first idea, this could be easily attained by treating the filter mats to be used with biocide or fungicide, such that the biocidal or fungicidal substances issuing from the said filter mat disinfect the device when the vapour extractor hood is switched on. Filter mats of this type were actually available on the market, but it has been shown in practice that the said filter mats cannot effectively create hygienic conditions. This results from the fact that, although the said bactericidal or fungicidal effect takes place when the vapour extractor hood is first switched on, as the cooking vapours act upon the filter mats, the collected fat droplets or oils prevent the further release of the bactericidal or fungicidal substances and accordingly the said filter mats cannot develop any anti-bacterial effect.

An object of the present invention is to disinfect filter mats of the type described above or the entire vapour exhaust device as a precautionary measure, so as to prevent the colonisation of bacteria and mould etc. or even toxic substances -- even in cases where the filter mats are not replaced in time or where the filter mats are replaced in time but a contamination of the entire device has already set in - by means of a disinfection which, if possible, is effective for the entire life of the apparatus used.

According to a first aspect of the present invention there is provided a process for disinfecting a vapour extractor hood, having a filter mat for filtering cooking vapours, characterized in that an apparatus which releases a disinfecting chemical is arranged adjacent the filter mat in the suction path of the vapour extractor hood.

According to a second aspect of the present invention there is provided a vapour extractor hood having a filter mat for filtering cooking vapours, characterized in that the hood includes an apparatus for releasing a disinfectant chemical which apparatus is arranged adjacent the filter mat, in the suction path ofthe hood.

A long-lasting disinfection and/or the creation of hygienic conditions in vapour extractor hoods of this type may be attained according to the present invention. Unlike attempts to date, the filter mat itself is no longer equipped with the said disinfecting chemicals. Instead, an apparatus is arranged near the filter mat, preferably above or below the filter plate of the vapour extractor hood, which apparatus releases the said chemicals which disinfect the filter mat into the air stream thereof whenever the filter mat is in operation, thus not only continuously disinfecting the filter mat during its entire period of use, but also at the same time preventing the colonisation of bacteria and mould throughout the device.

In this connection, the disinfecting chemicals may be a solution, a powder or a gas. Where solutions are used, it is recommended to produce them from a volatile liquid which has disinfecting chemicals dissolved or dispersed in it. In this case, the volatile liquid may be an alcohol, which has its own disinfecting effect. In addition, the evaporation or the release of the disinfecting chemicals may be assisted by heating a solvent container, the heating being switched on simultaneously with the vapour extractor hood. It is advantageous to use a membrane-active biocide or a mixture of membrane active biocides, more particularly an amphoteric tenside, as the disinfecting chemical.Amphoretic tensides of this type have the advantage that they completely moisten all parts of the vapour extractor hood, in particular the filter mats, and thereby kill bacteria or mould which has accumulated there.

In this connection, the solution can be absorbed in liquid form by means of an open-pore sponge, or in dried form in an air-permeable filter paper which is impregnated with the solution. It is generally important that a fat and/or oil barrier is arranged upstream of the sponge in the direction of flow of the drawn-in air, in order to avoid the effect described above, as a result of which the disinfecting chemicals would become ineffective.

Disinfection by means of a disinfecting gas is also easily conceivable, for example by means of ozone, in which case the apparatus according to the invention may comprise an ozone generator which converts atmospheric oxygen to ozone by means of electrical discharge. It is true that ozone is also harmful or poisonous to humans, but only a very small amount, which is still far from being harmful to humans, is necessary in order to effect a disinfection.

It is recommended to arrange an indicator at the front of the apparatus in the direction of flow of the drawn-in air, which indicates the saturation of the filter mat, such that a single apparatus may be used both to disinfect the entire device and to indicate the saturation of the filter mat used. In this case, the entire apparatus should be arranged above the filter plate or particularly advantageously below the said filter plate, in order that the indicator can be inspected without difficulty. In this connection, the saturation indicator can quite conceivably take over the function of the fat/oil barrier, which is necessary in order to protect the disinfecting chemicals.

In the simplest case, a filter paper impregnated with indicator substance can be placed on top of the filter plate and a further filter paper which is airpermeable and impregnated with a disinfecting solution placed on top of the first filter paper, in which case both papers are in the suction path of the vapour extractor hood, i.e. the drawn-in air passes through them. In this connection, the filter paper impregnated with indicator substance protects the filter paper which is impregnated with disinfecting solution and which is arranged above it from direct contact with the cooking vapours or oils and fats.

Spacers, for example plastics material grids or the like can of course also be added between the papers and also between paper impregnated with the disinfecting solution and the filter mat. Where necessary, the papers may of course be manufactured combined with the spacer in the form of an insertion mat which is placed onto the filter plate of the vapour extractor hood.

A recommended apparatus according to the invention is formed by means of a flat tray, on the perforated bottom of which is arranged an airpermeable filter paper which is impregnated with indicator substance, on top of this a spacer, and on top of the said spacer a filter paper which is also airpermeable and which is impregnated with the disinfecting chemical. An apparatus of this type can be manufactured economically and can be delivered together with the filter mat, which ensures that the said apparatus is also actually used and observed.

An embodiment of an apparatus according to the invention is shown in diagramatic form in the drawings, in which: Fig. 1 is an exploded view of the construction of an apparatus of this type and Fig. 2 is a plan view of the said apparatus.

In a flat, bowl-shaped tray 1,the bottom of which is provided with openings 2, a correspondingly dimensioned filter paper3 is fitted, which is impregnated with indicator substance. A spacer 4, for example plastics material matting, is placed onto the said filter paper 3. A further filter paper 5, which is impregnated with a disinfecting chemical, is placed over the said spacer 4. Where an amphoteric tenside is used as the disinfecting chemical, then approximately 500 ppm, which enters the recirculated air from the said impregnated filter paper 5, is sufficient to disinfect the entire device including the filter mat, such that no strains of bacteria or mould can colonise.

The entire apparatus is then secured to the underside of the filter plate of the vapour extractor hood, i.e. in the direction of flow 8 of the drawn-in air upstream of the said filter plate, for example by means of a pin 6, which projects through securing apertures 7 in the tray 1.

When the vapour extractor hood is in operation, the air is drawn in through the filter plate and the filter mat of the vapour extractor hood and passes either into the outside air or remains in the room as filtered recirculated air. In this connection, the apparatus according to the embodiment illustrated covers approximately 1% of the inlet area, such that the flow of air is only negligibly restricted. The flow of air, which approaches in the direction of the arrow, also passes through the openings 2 in the bowl-shaped tray 1 and here comes into contact with the filter paper 3 which is impregnated with indicator substance.In this connection the discoloration of the indicator substance as a result of the constant inflow of fat and oil is synchronous with the absorption of the filter mat inside the vapour extractor hood, such that in the case of a saturation of the said filter mat, there is also a change in the colour of the indicator, which thereby indicates the saturation of the filter mat. Since the said filter mat 3 is air-permeable, the flow of air passes in the direction of the arrow 8 through the spacer 4to also reach the filter paper 5 which is impregnated with the disinfecting chemical. Here it is charged with the said chemical, which it conveys further into the vapour extractor hood, where the said chemical can spread and can develop its bactericidal or fungicidal effect. This effect is particularly vigorous in cases where an amphoretic tenside is used as the disinfecting chemical, which, by means of its high capacity to moisten, spreads overall the surfaces of the device and also of the filter mat, and thereby leads to a reliable destruction of the bacteria and mould.

The bowl-shaped tray 1 can be manufactured from synthetic material or laminated paper, which means that the entire device is not only extremely simple but also economical to manufacture.

Claims

1. A process for disinfecting a vapour extractor hood, having a filter mat for filtering cooking vapours, characterized in that an apparatus which releases a disinfecting chemical is arranged adjacent the filter mat, in the suction path of the vapour extractor hood.

2. A process according to claim 1, in which the filter mat of the vapour extractor hood is arranged above a filter plate, characterized in that said apparatus is arranged above and/or below said filter plate.

3. A process according to claim 1, characterized in that the disinfecting chemical is a solution.

4. A process according to claim 3, characterized in that the solution comprises a disinfecting chemical which is dissolved or dispersed in a volatile liquid.

5. A process according to claim 4, characterized in that the volatile liquid is an alcohol.

6. A process according to claim 4, characterized in that the disinfecting chemical is a membrane-active biocide or a mixture of membrane-active biocides.

7. A process according to claim 6, characterized in that the biocide is an amphoteric tenside.

8. A process according to claim 3, characterized in that the apparatus comprises an open-pore sponge which absorbs the disinfecting solution.

9. A process according to claim 3, characterized in that the apparatus comprises an air-permeable filter paper which is impregnated with the disinfecting solution.

10. A process according to claim 8 or 9, characterized in that a fat and/or oil barrier is arranged upstream of the sponge or filter paper in the direction of flow of the drawn-in air.

11. A process according to claim 2, characterized in that the apparatus comprises a solution container which can be heated.

12. A process according to claim 1, characterized in that the disinfecting chemical is a powder.

13. A process according to claim 1, characterized in that the disinfecting chemical is a gas.

14. A process according to claim 13, characterized in that the device is an ozone generator, which converts atmospheric oxygen to ozone by means of an electrical discharge.

15. A process according to claim 1, characterized in that an indicator, which indicates the saturation of the filter mat, is arranged at the front of the apparatus in the direction of flow of the drawn-in air.

16. A process according to claims 10 and 15, characterized in that the indicator comprises the fat" oil barrier.

17. A process according to one or more of the preceding claims, characterized in that the apparatus comprises a flat tray having a perforated bottom upon which is arranged an air-permeabie filter paper, which is impregnated with indicator substance, on top of this a spacer and on top of the said spacer a filter paper, which is also airpermeable and which is impregnated with disinfecting chemicals.

18. A process according to one or more of the preceding claims, characterized in that the apparatus is a ready-made pad, comprising a filter paper which is impregnated with indicator substance, a spacer in the form of a grid which is placed over the filter paper, and a final filter paper which is impregnated with a disinfecting chemical.

19. A process for disinfecting a vapour extractor hood, substantially as hereinbefore described.

20. A vapour extractor hood having a filter mat for filtering cooking vapours, characterized in that the hood includes an apparatus for releasing a disinfectant chemical which apparatus is arranged adjacent the filter mat, in the suction path of the hood.

21. A hood according to claim 20, in which the filter mat is arranged above a filter plate, characterized in that said apparatus is arranged above and/or below said filter plate.

22. A vapour extractor hood having a filter for filtering cooking vapours and, located downstream of air flow through the filter, disinfecting means arranged to release a disinfecting chemical.

23. A vapour extractor hood substantially as hereinbefore described with reference to the accompanying drawings.

24. A disinfecting means for a vapour extractor hood according to claim 24, substantially as herein before described, or with reference to the accompanying drawings.

25. The features hereinbefore disclosed or their equivalent, in any novel selection.