Technical Field

The invention relates to a device for disinfecting, and possibly also deodorizing, the air by using an ozone generator that creates ozone in the air of a room being disinfected and deodorized. The present invention also relates to a method of operating of the air disinfection device for providing optimal disinfection.

Background of the Invention

From a medical perspective, two categories of health problems have been identified that are associated with people staying in enclosed spaces of buildings. These are Sick Building Syndrome (SBS) and Building-Related Illness (BRI), which in all cases relate to physical, chemical, or biological agents in the respective spaces. In view of the fact that most people, especially in urban agglomerations, spend more than 90 % of their time in enclosed spaces of buildings, the aforementioned problem has become very topical.

A study by the Environmental Protection Agency US (EPA US) reported manyfold exceedance of allowed limits for indoor spaces of buildings, which were up to 100 times higher in extreme cases. In the document Mold Remediation in Schools and Commercial Buildings (EPA 402-K-01 -001 , 2008), the U.S. government standard for molds, the relevant negative health effects in indoor spaces of buildings are listed, among other things. Molds are found almost everywhere and can grow on virtually any organic matter, as long as it is sufficiently humid. In general, overexposure to even common molds can cause or worsen conditions such as asthma, hay fever, or other allergies. Mold colonies, often invisible to the eye, also represent an accumulator of surface humidity, which provides a breeding ground for other pathogens and allergens, such as mite feces, spores, bacteria, viruses, amoebae, plant debris, etc.

MRSA (Methicillin-resistant Staphylococcus aureus), Escherichia coli, and VRE (Vancomycin-resistant Enterococcus) are bacteria responsible for serious infections in hospitals and other medical facilities (“nosocomial” infections) and are resistant to standard purification procedures and most antibiotics. These organisms grow in biofilms that form on humid surfaces and protect the bacteria from adverse environmental factors. They are often incorporated into the matrix of the extracellular polymeric substance (EPS) itself, which is a polymeric conglomerate generally composed of extracellular DNA, proteins, and polysaccharides. Biofilms form on surfaces including fabrics, fibrous and porous surfaces such as clothing, curtains, carpets and the fibrous contents of walls, ceilings and, room partitions. Many people work in enclosed buildings or offices, and not being able to open windows always means there is a lack of fresh air to circulate in the building. Once a porous surface, such as carpet, curtain, wood, porous ceiling material, etc., is contaminated with bacteria or viruses, it cannot be effectively disinfected using commonly available products and procedures. In this field, the problem of sanitation of indoor spaces using a range of subtle biocidal agents is very urgent, the most common of which are UVC radiation from germicidal emitters, hydrogen peroxide vapor, and ozone. And ozone, known for being a powerful antifungal, antibacterial, and virucidal agent, has been used in water purification for many years. Its high oxidation potential of 2.07 eV and relatively simple preparation directly from air make it an ideal medium for the sanitation of indoor spaces of buildings.

There are currently several patents CN1 1 1671957 A, US8992829 B2, EP1692259 A2 a US7407624 B2, which are directed to the sanitation of indoor spaces by a combination of ozone, hydrogen peroxide vapors, and in some cases germicidal UVC radiation. The disinfectant gaseous mixture here is composed of air, ozone, and hydrogen peroxide vapors. Their simultaneous action is synergistic and different from the separate additive action of each of the individual gases. While peroxide vapors are effective on smooth surfaces, the effects of ozone are universal and are also effective in porous materials. The germicidal UVC radiation, traditionally used in medical facilities, is limited by the area of illumination compared to both gaseous media and does not work in shaded areas. The main drawback of the existing solutions is the lack of optimization of the entire disinfection and deodorization process. In particular, there is a need to achieve the maximum biocidal effectiveness of ozone with minimal degradation of materials in the disinfected space, wherein appropriate optimization should also ensure the minimum intensity of ozone production from air without the need to add additional media, such as hydrogen peroxide, etc.

Summary of the Invention

The aforementioned drawbacks are to a certain extent eliminated by an air disinfection device comprising a storage housing, at least one inlet fan adapted to blow air into the storage housing, at least one outlet fan adapted to expel air out of the storage housing, an ozone generator, a temperature sensor, a humidity sensor, an ozone detector, and a control unit communicatively connected to the temperature sensor, the humidity sensor, and the ozone detector. The device of the present invention is characterized in that the temperature sensor, the humidity sensor, and the ozone detector are adapted to sense the parameters of the air blown into the storage housing by the inlet fan, wherein the control unit is communicatively connected to the ozone generator and comprises a regulation element adapted to regulate the output of the ozone generator based on a time course of the current value of the ozone concentration Cact(7) from the ozone detector.

Because the air parameters (temperature, humidity, ozone concentration) blown into the storage housing are sensed, there is no need for the device to be provided with wiring for connection to any external sensors. This means that the temperature sensor, humidity sensor, and ozone detector are arranged in the immediate vicinity of the inlet fan, either inside the storage housing or outside the storage housing. This provides a sufficiently compact arrangement of the device without the need for extensive wiring and thus also makes it easier and less costly to install the device in various spaces. Thanks to the sensing of said parameters and the regulation element of the control unit, it is also possible to use the device to optimize the disinfection process in order to achieve maximum biocidal effectiveness of ozone with minimal degradation of materials in the disinfected space. Appropriate optimization also ensures that the intensity of ozone production from air is minimized without the need to add additional media, such as hydrogen peroxide, etc.

The temperature sensor, humidity sensor, and ozone detector are preferably arranged inside the storage housing. This ensures that the device is compact in that no external sensors are used that would require the installation of extensive wiring. The device can thus be easily and cost-effectively placed in various spaces.

The ozone generator is preferably implemented as a corona discharge generator. It is a reliable and relatively inexpensive ozone generator that uses the simple principle of splitting oxygen O2 molecules by discharge to produce ozone. The resulting highly reactive oxygen O atoms subsequently react with oxygen O2 molecules to form the ozone O3 molecule.

The regulation element is preferably implemented as a PID regulator. The PID regulator is a readily available regulator that allows the regulated variable to be regulated to a specific desired value by changing the value of a certain action variable. Thus, such a regulator can be used to optimize the disinfection process performed by the device of the present invention.

The air disinfection device further preferably comprises a display and a control element. Thanks to the display, all important information can be displayed directly on the device, e.g. about the measured parameters or set operating modes. Using the control element, e.g. a button or a remote control, various parameters can be set, e.g. operating mode, disinfection duration, or disinfection repetition setting, etc.

The storage housing is preferably square-shaped and is usable as a ceiling cassette, wherein the inlet fan and the outlet fan are arranged on the same side of the storage housing. In the embodiment of a ceiling cassette, the device does not visually disturb the respective space and is characterized by good compactness and easy installation.

The air disinfection device further preferably comprises travel wheels, wherein the inlet fan and the outlet fan are arranged on different sides of the storage housing. Thanks to the travel wheels, the device can be easily moved within the space to be disinfected or between individual spaces as required, and is also suitable for disinfecting large enclosed spaces, e.g. halls and assembly plants. Due to the fact that the inlet and outlet fans are arranged on opposite sides, there is no aerodynamic short-circuit air flow between them.

The aforementioned drawbacks are also eliminated to a certain extent by a method of operating of the air disinfection device according to the present invention comprising the steps of:

- supplying air to the storage housing using the inlet fan;

- creating ozone using the ozone generator in the air supplied to the storage housing;

- and exhausting air from the storage housing using the outlet fan.

The method according to the present invention is characterized in that it further comprises the steps of:

- measuring the temperature t of the air supplied to the storage housing using the temperature sensor;

- measuring the humidity h of the air supplied to the storage housing using the humidity sensor;

- measuring the concentration C of ozone in the air supplied to the storage housing using the ozone detector;

- measuring at least two time parameters indicating the time it takes for the measured concentration C of ozone to reach the specified upper limit value Cmax for at least two set output levels of the ozone generator;

- calculating the optimal time course of the concentration Copt(7) of ozone, wherein this time dependence is a parametric function of the temperature tand humidity h of the air supplied to the storage housing and the measured at least two time parameters; measuring the current concentration Cact(7) of ozone in the air supplied to the storage housing (2) using the ozone detector (8) and obtaining a time course of the current value of the concentration Cact(7) of ozone; - and regulating the output of the ozone generator using the control unit to minimize the difference between the optimal time course of the concentration Copt( 7) of ozone and the time course of the current value of the concentration Cact(T) of ozone.

The advantage of the method according to the present invention is characterized primarily in that it allows optimization of the process of disinfection (or purification) of air with ozone, wherein maximum biocidal effectiveness of ozone is achieved with minimal degradation of materials in the disinfected space. This optimization also ensures that the intensity of the production of ozone from air is minimized without the need to add additional media, such as hydrogen peroxide, etc. In addition, the disinfection process takes place automatically according to the predefined setting of the relevant parameters.

In the method of operating of the air disinfection device, in the step of measuring at least two time parameters, a first time parameter 7i and a second time parameter T2 are preferably measured, wherein the first time parameter 7i indicates the time it takes for the measured concentration C of ozone to reach a specified upper limit value Cmax at the maximum output of the ozone generator, and the second time parameter T2 indicates the time it takes for the measured concentration C of ozone to reach the specified upper limit value Cmax at half the output of the ozone generator, wherein the calculated optimal time course of the concentration Copt(7) of ozone, which is calculated in the step of calculating the optimal time course of the concentration Copt(7) of ozone, is a parametric function of the first time parameter 7i and the second time parameter T2. Thanks to the calibration performed in this way, the disinfection process can then be reliably performed using the knowledge of the optimal course of the concentration Copt(T) of ozone for the given space, thus allowing variable use of the device in various spaces.

The upper limit value of the concentration Cmax of ozone is preferably specified from the interval (100 ppm, 1000 ppm). Within this range, sufficient biocidal effects are achieved in a reasonable time, wherein at a concentration of 1000 ppm, biocidal effects of 99,9 % are achieved in a reasonable time. Description of the Drawings

A summary of the invention is further clarified using exemplary embodiments thereof, which are described with reference to the accompanying drawings, where:

Fig. 1 shows an illustrative diagram of the device according to the present invention;

Fig. 2 shows a diagram of an exemplary method of operating of the device according to the present invention; and

Fig. 3 shows a detailed flow chart of an exemplary method of operating of the device according to the present invention.

Exemplary Embodiments of the Invention

The invention will be further clarified using exemplary embodiments with reference to the respective drawings, which, however, have no limiting effect on the scope of the invention.

The object of the invention is an air disinfection device 1_. The air disinfection device 1 comprises a storage housing 2, which forms a casing for the air disinfection device 1 and houses other components of the air disinfection device T The storage housing 2 is provided with at least one inlet fan 3 and at least one outlet fan 4. The inlet fans 3 are arranged and oriented so as to blow air into the storage housing 2 by movement of the blades. The outlet fans 3 are oriented so as to expel air out of the storage housing 2 by movement of the blades. The fans 3, 4 are arranged in such a way that no aerodynamic short-circuiting occurs during the flow of the air blown into the storage housing 2 and expelled out of the storage housing 2, or the air expelled by the outlet fans 4 is not drawn in by the inlet fans 3 and blown into the storage housing 2 immediately after leaving the storage housing 2. As an example, the fans 3, 4 are arranged so that the distance between their centers lies in the range of 220-400 mm. For example, the operating diameter of the fans 3, 4 has a value in the range of 100-120 mm. For example, the maximum value of the operating flow rate of the fans 3, 4 lies in the range of 2-6 m ³ /min.

The air disinfection device 1 further comprises an ozone generator 5. In a first exemplary embodiment, the ozone generator 5 is implemented as a generator of electrical discharge, in particular corona discharge or barrier discharge; alternatively, the ozone generator 5 may be implemented as an ultraviolet lamp. The air supplied to the ozone generator 5 contains a constituent of molecules of oxygen O2. The oxygen molecules are split by the electric discharge into individual oxygen atoms, which can recombine to form unstable molecules of ozone O3. After some time, the ozone molecules break down into an oxygen molecule and atomic oxygen, which then also recombines into an oxygen molecule. The ozone generator 5 comprises typical electronic elements that allow the inlet mains voltage to be received and transformed into the values required for the operation of the ozone generator 5. The output of the ozone generator 5 generally depends on the size of the space to be disinfected, wherein for larger spaces a higher output is used and for smaller spaces a lower output is used. However, the output of the ozone generator 5 is primarily regulated depending on the values of the concentration C of ozone obtained from the ozone detector 8, as will be described below.

The air disinfection device 1 further comprises at least one temperature sensor 6 placed in the vicinity of the inlet fan 3 so as to be able to sense the temperature of the air blown into the inner space of the storage housing 2 of the air disinfection device T The air disinfection device 1 further comprises at least one humidity sensor 7 placed in the vicinity of the inlet fan 3 so as to be able to sense the humidity of the air blown into the inner space of the storage housing 2 of the air disinfection device 1_. The air disinfection device 1 further comprises at least one ozone detector 8 placed in the vicinity of the inlet fan 3 so as to be able to sense the concentration of ozone in the air blown into the inner space of the storage housing 2 of the air disinfection device T As mentioned above, the temperature sensor 6, the humidity sensor 7, and the ozone detector 8 are placed in the vicinity of the inlet fan 3. That is, they may be placed inside the storage housing 2, such as e.g. in the first exemplary embodiment of fig. 1 , or also on the outer side of the storage housing 2, if such an embodiment ensures that the parameters of the air currently being blown into the storage housing 2 are sensed.

The air disinfection device 1 further comprises a control unit 9 communicatively connected to the fans 3, 4, the ozone generator 5, the temperature sensor 6, the humidity sensor 7, and the ozone detector 8. A communicative connection means a connection that allows the transmission of data, information or an electrical control signal between the communicatively connected elements. The communicative connection can also be implemented wirelessly. The transmitted information or data are temperature values measured by the temperature sensor 6, humidity values measured by the humidity sensor 7, and ozone concentration values measured by the ozone detector 8, or the current operating parameters of the fans 3, 4, e.g. the number of revolutions determining the air flow rate, or the operating parameters of the ozone generator 5, e.g. the operating output. The electrical control signal means sending control instructions to the communicatively connected elements, e.g. regulation of the revolutions of the fans 3, 4, regulation of the output of the ozone generator 5, or starting of individual elements. The control unit 9 further comprises a regulation element, which is, for example, implemented as a PID regulator. The control unit 9 further comprises a memory adapted to store at least one operating program. The operating program means a set of instructions for the individual elements that the control unit 9 controls and to which it is communicatively connected.

In one possible exemplary embodiment, two inlet fans 3 and two outlet fans 4 are used, wherein the fans 3, 4 are provided on the same side of the storage housing 2. The storage housing 2 is square-shaped and its dimensions correspond to those of a ceiling cassette with 500-800mm sides. For example, the air disinfection device 1 of the present embodiment is placed in the ceiling of the room instead of the ceiling cassette.

In an alternative exemplary embodiment, two to four inlet fans 3 and an equal number of outlet fans 4 are used, wherein the inlet fans 3 are placed on the opposite side of the storage housing 2 from the outlet fans 4. In this exemplary embodiment, the air disinfection device 1 is provided with travel wheels for easy movement thereof.

In the following section, the method of operating of the air disinfection device 1 will be described with emphasis on optimizing the disinfection process and using Fig. 2 and Fig. 3.

As can be seen in Fig. 2 or Fig. 3, after the air disinfection device 1 installed in the space to be disinfected is started, firstly, the air disinfection device 1 is set and the air disinfection device 1 is calibrated. The step of setting the air disinfection device 1 comprises, for example, setting the current date and time, setting the operating mode (these will be described in more detail below), setting the duration or repetition of the disinfection, etc. The setting of the air disinfection device 1 may be performed e.g. by input via a control interface arranged on the storage housing 2, wherein the control interface comprises, for example, a display and at least one control element, e.g. a button. Alternatively, the setting (e.g. selection of the operating mode) can be performed by means of a remote control adapted for wireless communication with the control unit 9 and for selective selection of the operating mode. Alternatively, the operating modes are selected automatically by the control unit 9, e.g. depending on the time of day, e.g. by setting a regular cycle, the current ozone concentration, etc.

The calibration of the air disinfection device 1 is then carried out in the following method. First the inlet fans 3 and the outlet fans 4 are started. The output of the fans 3, 4 corresponding to the air flow rate is set to the maximum possible value that the fan 3, 4 is capable of providing or that is tolerable in terms of the noise of the fans 3, 4 and that ensures sufficient air circulation in the space being disinfected. This value lies, for example, in the range of 2-6 m ³ /min. The temperature sensor 6 measures the temperature t of the air blown into the storage housing 2 by the inlet fan 3 or the temperature t of the air in the immediate vicinity of the air disinfection device T The humidity sensor 7 measures the humidity h of the air blown into the storage housing 2 by the inlet fan 3 or the humidity of the air in the immediate vicinity of the air disinfection device 1.

After detecting the temperature t and humidity h of the air, the ozone generator 5 is started and ozone is generated in the supplied air. The air containing the ozone constituent is blown into the room by the outlet fan 4.

Then the first time parameter marked as 7i is measured. The parameter 7i indicates the time it takes for the value of the concentration C of ozone in the air supplied to the storage housing 2, at the current temperature t and humidity h of the air the given room, to reach the maximum defined level (or upper limit value) of the concentration Cmax of ozone at the maximum output of the ozone generator 5. The upper limit value of the concentration Cmax of ozone is selected depending on the type of the room, its use, and the types of materials present in the room. The upper limit value of the concentration Cmax of ozone lies in the interval 100-1000 ppm. Then the second time parameter marked as T2 is measured. The parameter T2 indicates the time it takes for the value of the concentration C of ozone in the air supplied to the storage housing 2, at the current temperature t and humidity h of the air the room, to reach the maximum defined level (or upper limit value) of the concentration Cmax of ozone at half the output of the ozone generator 5.

Based on this calibration, i.e. based on the obtained values of the temperature of the air t, humidity of the air h, the first time parameter 7i and the second time parameter 72, the optimal time course of the concentration C _op t(7) of ozone in the room is subsequently specified.

The optimal time course of the concentration Cbpt(7) of ozone at the temperature t and humidity h is specifically calculated using the following formula: wherein

^max ~ D(t, h) X CQ, where D(t,h) denotes the so-called degradation parameter at the temperature t and humidity h, Co corresponds to the maximum ozone concentration that the ozone generator 5 would produce in an infinitely long time, and P(T, Ti, T2,t,/?) is the so-called output parameter at the temperature t and humidity h that characterizes the space being disinfected. T denotes time.

Subsequently, the air disinfection device 1 is operated according to the selected operating mode. In the air disinfection operating mode, air from the room is supplied to the storage housing 2 by the inlet fan 3 and ozone is created in the supplied air by the ozone generator 5 from oxygen molecules by an electrical discharge, for example, a corona discharge. The ozone detector 8 measures the current concentration of Cact(7) of ozone in the air supplied to the storage housing 2 by the inlet fan 3. The control unit 9 stores the current values of the concentration Cact(7) of ozone in the air supplied to the storage housing 2 by the inlet fan 3, thereby obtaining a time course of the current value of the concentration Cact(T) of ozone. The control unit 9 subsequently compares the time course of the current value of the concentration Cact(T) of ozone with the values of the optimal time course of the concentration C _O pt(7) of ozone in the room and, using a regulation element of the control unit 9, i.e. specifically, e.g. a PID regulator, regulates the output of the ozone generator 5 so that the values are as close as possible, or so that the difference in values (Copt(7) - Cact(7)) is minimal. This difference is minimized by regulating the output of the ozone generator 5, while the fan speed remains constant and at the maximum possible value to allow sufficient air circulation but does not entail excessive noisiness. For example, this value is selected from a range of 2-6 m ³ /min, depending on the size of the area being disinfected.

As can be seen in the detailed flow chart in Fig. 3, the operating mode of air disinfection (also referred to as air purification) can be started immediately, e.g. by entering a code on a remote control or other control element, or on a pre-selected day and time. The disinfection itself can also take place in several phases, such as the preparation of the purification, in which the starting of the fans occurs and lasts about 1 minute, and also the starting of the purification itself for a pre-set time. During the disinfection, the output of the ozone generator 5 is then regulated by the control unit 9, namely the PID regulator, as described above to achieve optimization of the disinfection.

However, the disinfection device 1 can also be operated in a second operating mode, namely the air deodorization operating mode. This operating mode allows the aromatic odor molecules to be split by periodic dosing of ozone at levels safe for the human body. The maximum ozone concentration used for deodorization is 50 ppb. As shown in Fig. 3, for example, ozone is introduced into the room every 15 minutes for 1 second and subsequently the fans 3, 4 are started for 10 seconds.

Industrial Applicability

The invention can also be used as a mobile device for disinfection and deodorization of rooms; according to an alternative exemplary embodiment, the device can be provided as a ceiling cassette. List of Reference Signs

1 - air disinfection device

2 - storage housing

3 - inlet fan

4 - outlet fan

5 - ozone generator

6 - temperature sensor

7 - humidity sensor

8 - ozone detector

9 - control unit