WO2008128305A1

WO2008128305A1 - Improved method for decontaminating and/or deodorizing air conditioning systems and cover systems and cover applied thereby

Info

Publication number: WO2008128305A1
Application number: PCT/BE2008/000028
Authority: WO
Inventors: Koen Jan Lieven De Koster
Original assignee: Metatecta, Naamloze Vennootschap
Priority date: 2007-04-19
Filing date: 2008-04-17
Publication date: 2008-10-30
Also published as: BE1017561A3

Abstract

Method for decontaminating and/or deodorizing an air conditioning system (1) provided with at least two openings (2), characterised in that the method consists in connecting one opening (2) by means of a cover (3) to an atomizer (4) for atomizing biocidal or deodorizing components in the form of an aerosol into the air duct (1), and in connecting another opening (2) to an aspirator (5) to gradually suck in the aerosol, and in hermetically sealing the remaining openings (2), whereby the cover (3) is partly formed of a membrane (8) which is permeable to air but which forms a barrier to the atomized components.

Description

Improved method for decontaminating and/or deodorizing air conditioning systems and cover applied thereby.

The present invention concerns a method for decontaminating and/or deodorizing an air conditioning system.

In particular, the invention provides solutions to neutralize the most resistant viruses, bacteria, fungi, spores and unpleasant smelling molecules in an air conditioning system, for example in an air duct of an airco or evaporation system or in a standalone airco unit.

It is known that the sources which are to blame for infections or bad smells are situated in places or on surfaces that are difficult to access for man, such as in the air ducts of for example airco or evaporation systems in which condensate is permanently being formed. The combination of dust particles and condensate in these places forms an ideal breeding ground for fungi and bacteria which lead to germs and/or bad smells being spread.

It is also known that in this case, a traditional dedusting, for example by means of flexible hoses, is not recommended. For, the bio film that is present is removed and spread rather when dedusting in a conventional manner, resulting in a higher contamination risk in many cases.

It is also known that, in case of an extreme contamination, use can be made of biocides to neutralize the bio films that are present.

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;. ϋ¹ v.m A disadvantage to the use of biocides is that the operating environment of the air duct of for example the airco or evaporation system must be cleared so as not to expose anyone to these toxic or irritating biocides.

Additional disadvantages are that the operating environment is not available then and that it is a time and energy- consuming, costly process.

Apart from that, it is known to test the germ load of an environment or plant in an objective manner by means of an ATP bioluminescence test. Adenosine triphosphate (ATP) is the basic fuel of all living organisms and thus it is found in all micro-organisms. The test consists in measuring the enzyme of the firefly, named luciferase or luciferine. This metabolite is in fact a chemical fingerprint which makes it possible to measure the amount of micro-organisms that are present by means of a linear relationship between the measured luminosity and the ATP concentration. When a sample of the environment is taken, this is put in a luminometer, and the result can be read from a display within half a minute. This result is expressed in Relative Light Units (RLU) and indicates an equivalent amount of micro-organisms, expressed as Colony Forming Units per cm². Table 1 illustrates the relation between said two units.

Table 1. Relation between RLU and CFU.

RLU CFU /cm² implication to the environment

This technique was first applied in 1947 and makes it possible to measure the neatness of the surfaces in an environment in a relatively simple and fast manner, in particular also of air conditioning systems.

The present invention describes a method which aims to disinfect or deodorize air conditioning systems such as air ducts of for example airco or evaporation systems in a fast and efficient manner and to remedy one or several of the above-mentioned and other disadvantages.

To this end, the invention concerns a method for decontaminating and/or deodorizing an air conditioning system which is provided with at least two openings, whereby the method consists in connecting one opening by means of a cover to an atomizer for atomizing biocidal or deodorizing components in the form of an aerosol in the air conditioning system, and in connecting another opening to an aspirator to gradually suck in the aerosol, and in hermetically sealing the remaining openings, whereby the cover is formed of a membrane which is permeable to air but which forms a barrier to the atomized components.

An advantage of this method is that, thanks to the gradual decontamination and/or deodorization by the atomizing of active components, every source of contamination and smell, wherever in the air conditioning system concerned, is neutralized.

A major additional advantage is that, thanks to this method for disinfecting and/or deodorizing an air conditioning system such as for example the air duct of an airco or evaporation system, the operational environment must not be entirely sealed and any persons present may continue their work, which is only advantageous to the economy.

Another advantage is that the method makes it possible to disinfect and/or to deodorize in a relatively fast and efficient manner. Measurements have pointed out, for example, that after a maximum period of operation of 30 minutes of the method according to the present invention, a log 7 reduction, i.e. a factor of 10 million of less dangerous germs such as Clostridium Difficile and Methicilline-resistant Staphylococcus aureus (MRSA) , is obtained.

The method according to the present invention for decontamination preferably makes use of an aerosol which consists of some 97% of osmosed water (H₂O) and, as active components, 3% hydrogen peroxide (H₂O₂), 0.006% silver ions (Ag⁺) and less than 0.001% organic phosphate.

This decontaminant is advantageous in that not only the germ load is lowered by atomizing an H20₂ solution, but in that it guarantees a germ-restraining / germ-resistant effect in the long term. The active components thank their efficiency to the oxidizing effect of H₂O₂ and the oligodynamic effect of the silver ions. This oxidizing operation implies that H₂O₂ penetrates into the spores and bacterial cell walls of micro-organisms by means of oxidation into the intracellular matrix and oxidizing proteins, DNA and other cellular components, resulting in their destruction. The silver ions (Ag⁺) have a triple antimicrobial effect: they react with proteins and enzymes that are important to the bacterial energy production as well as to the transport of major particles through the cell membrane and into the cell. They inhibit the cell division through the interaction with DNA and they connect to the cell wall and lead to lysis.

An additional advantage is that the silver ions, in the shape of nano particles that are present, have a bacteriostatic remenant effect which stops recontamination in the near future, and in that the small fraction of organic phosphates have an anti-corrosive effect. Thanks to the extremely low concentration of Ag⁺ (0.1 times the tolerated amount in drinking water) , these active components are moreover completely harmless to man. A mist formed of less than 5% of H₂O₂ is not considered to be dangerous either.

For the deodorization according to the method of the present invention, use is preferably made of a neutral, non-allergenic, odoriferous liquid based on surfactants for the aerosol. These surfactants seek out oily molecules, such as petroleum (having a high viscosity) and isolate them and make them heavier by forming a micelle. This micelle reduces the surface tension of said oily molecule, resulting in neutralization. Combined with the aforesaid preferred aerosol for decontamination, also organic odour molecules may be neutralized.

The aerosol deodorizes air conditioning systems such as air ducts of for example an airco or evaporation system and then deposits on the inner surfaces, which results in a deodorizing effect. Preference is hereby given to substances that are being slowly released, working for several days and producing a delicate perfume.

The method according to the present invention preferably makes use of a cover that is entirely or partly made of Tyvek®. Tyvek® is a material made of polyethylene fibres with a high density, letting water gas and air through, but not the active components that are used in the aerosol.

The invention also concerns a cover that can be applied with the method as described above.

In order to better explain the characteristics of the invention, the following embodiments of a method for decontaminating and/or deodorizing an air conditioning system according to the invention are given as an example only without being limitative in any way, with reference to the accompanying drawings, in which:

figure 1 illustrates the method schematically and seen in perspective, as applied to an air conditioning system in the form of an air duct, figure 2 illustrates the method schematically and seen in perspective, as applied to an air conditioning system with branches .

A preferred method for decontaminating and/or deodorizing an air conditioning system is illustrated by means of figure 1 and consists in connecting an air conditioning system 1 having at least two openings 2 to an atomizer 4 by means of a cover 3 in order to atomize biocidal or deodorizing components in the form of an aerosol into the air conditioning system 1, in connecting another opening 2 to an aspirator 5 to gradually suck in the aerosol, and in hermetically sealing the remaining openings 2.

Figure 1 shows that the cover 3 has connectors 6 which entirely encompass the opening 2, as well as a flanged joint 7 which is connected to the atomizer 4. The cover 3 is partly formed of a membrane 8 which is permeable to air but which forms a barrier to the atomized components 5.

The atomizer 4 which is used in the method according to the invention is of a known type. For the sake of completeness, it should be mentioned that the atomizer 4 is provided with a venturi nozzle or throttle valve, a connector for an air-tight coupling to the flanged joint 7 of the cover 3, a liquid reservoir and an air compressor with adjustable pressure. The atomizer 4 may possibly be provided with two venturi nozzles. For a combined decontamination and deodorization, the atomizer 4 may be extendable in height and be provided on a frame with wheels .

It is important that the venturi nozzle or the throttle valve of the atomizer 4 can make the size of the active components in the aerosol vary.

The desired size of the active components in the method according to the invention is situated between 3 and 10 μm.

Larger active components would not float long enough in the aerosol and would deposit too quickly. However, when the active components are smaller than 3 μm, we can no longer speak of an aerosol, but of a gas, whereby the components stay floating too long and consequently do not make contact with the bio film that is present. Preferably, active components having a size between 5 and 10 μm are atomized.

The method further consists in making the atomizer 4 atomize for a sufficiently long time in order to make a sufficient amount of aerosol enter the air conditioning system 1, which may be sucked in by the aspirator 5 immediately or after a certain while, such that the aerosol gradually spreads over the air conditioning system 1.

In the method according to the present invention, a sample 9 is preferably taken before and after the decontamination, such that it is possible to establish whether the required degree of decontamination has been reached. In the exceptional case where the required degree of decontamination has not been reached and the environment of the air conditioning system 1 cannot be regarded as safe yet as a function of the measured number of Relative Light Units (RLU) on the basis of Table 1, the method is repeated. In the method according to the present invention, it will be measured preferably also after the decontamination how much ppm of H₂O₂ there is still present in the air duct so as to check when the environment of the air conditioning system 1 is safe after the H₂O₂ has been disintegrated. Typically, H₂O₂ disintegrates in H₂O and O₂ within a timespan of two hours.

In the described method, the air conditioning system consists of an air duct with only one section, but it is clear that the air conditioning system 1 may consist of several sections, for example for several offices or partial spaces, as illustrated in figure 2. The method according to the invention then consists in mutually sealing these sections by means of sealing means before carrying out the treatment according to the method and successively treating the sections.

In the specific case of an air conditioning system 1 in the form of a stand-alone inside airco unit, the principle of the method according to the invention is the same. The outer coffer casing is hereby preferably cleaned and disinfected first, after which the atomizer 4 is connected to the coffer casing by means of the cover 3. The aspirator 5 is in that case situated inside the inner airco unit. After the atomizer has then been spreading aerosol in the inner airco unit during for example 1 minute, the aspirator can suck in during 1 minute, which implies that the inner airco unit is switched on. The atomizer 4 is then disconnected from the cover 3. The active components can do their work for a certain period as the membrane 8 prevents the active components from escaping. Samples 9 are preferably taken to evaluate the degree of decontamination .

The present invention is by no means limited to the embodiments described as an example and represented in the accompanying drawings; on the contrary, such a method for decontaminating or deodorizing an air conditioning system 1 such as an air duct of for example an airco or evaporation system according to the invention can be made in many ways while still remaining within the scope of the invention.

Claims

Claims .

1.- Method for decontaminating and/or deodorizing an air conditioning system provided with at least two openings (2), characterised in that the method consists in connecting one opening (2) by means of a cover (3) to an atomizer (4) for atomizing biocidal or deodorizing components in the form of an aerosol in the air conditioning system (1), and in connecting another opening (2) to an aspirator (5) to gradually suck in the aerosol, and in hermetically sealing the remaining openings (2) , whereby the cover (3) is partly formed of a membrane (8) which is permeable to air but which forms a barrier to the atomized components.

2.- Method for decontaminating and/or deodorizing an air conditioning system according to claim 1, characterised in that biological samples (9) are taken according to the ATP bioluminescence methodology, before as well as after the above-mentioned atomization.

3.- Method for decontaminating and/or deodorizing an air conditioning system according to claim 2, characterised in that the results of the samples (9) are processed and interpreted in a report which visually represents the results .

4.- Method for decontaminating and/or deodorizing an air conditioning system according to claim 3, characterised in that as a function of the above-mentioned results of the samples (9) of the environment of the air conditioning system (1), the method is either or not repeated until the results indicate that the environment can be regarded as safe.

5.- Method for decontaminating and/or deodorizing an air conditioning system according to any one of the preceding claims, characterised in that the active components consist of 3% hydrogen peroxide (H₂O₂), 0.006% silver ions (Ag⁺) and less than 0.001% organic phosphate.

6.- Method for decontaminating and/or deodorizing an air conditioning system according to any one of the preceding claims, characterised in that the above-mentioned cover (3) is provided with connectors (6) which entirely encompass the opening (2) to which the above-mentioned cover (3) is connected on the one hand, and with a flanged joint (7) which is connected to the atomizer (4) on the other hand.

7. - Method for decontaminating and/or deodorizing an air conditioning system according to claim 6, characterised in that the membrane (8) of the above-mentioned cover (3) is made of polyethylene high-density fibres.

8.- Method for decontaminating and/or deodorizing an air conditioning system according to any one of the preceding claims, characterised in that the above-mentioned atomizer (4) is provided with a spray nozzle which makes it possible to adjust the size of the components in the aerosol between 5 and 10 micrometer.

9.- Method for decontaminating and/or deodorizing an air conditioning system according to any one of the preceding claims whereby the above-mentioned air conditioning system (1) consists of several sections that are mutually sealed and treated respectively.

10.- Cover for decontaminating and/or deodorizing an air conditioning system to be applied in a method according to anyone of the preceding claims, characterised in that the cover (3) is partly formed of a membrane (8) which is permeable to air but which forms a barrier to the atomized components .

11.- Cover for decontaminating and/or deodorizing an air conditioning system according to claim 10, characterised in that the cover (3) is provided with connectors (6) which entirely encompass the opening (2) to which the above- mentioned cover (3) is coupled on the one hand, and with a flanged joint (7) which is connected to the atomizer (4) on the other hand.

12.- Cover for decontaminating and/or deodorizing an air conditioning system according to claim 10, characterised in that the membrane (8) of the cover (3) is made of polyethylene high-density fibres.