FIELD OF THE INVENTION

The present invention relates to a filter construct for filtering gas and more particularly to a filter construct according to preamble of claim 1. The present invention further relates to an air cleaner device for removing contaminants from air and more particularly to an air cleaner device according to the preamble of claim 18.

BACKGROUND OF THE INVENTION

A mechanical air filters and filter devices comprise porous materials which remove solid particulates such as dust, mold spores, and bacteria from the air. Particles are captured by the filter material with impaction, interception, and diffusion. Air filters are used in applications where air quality is important, for example in building ventilation systems such as offices, clean rooms, hospitals, and also in industrial applications such as nuclear power stations and engines. Different kinds of filters are also used for personal protection for example in face masks.

The filtrations applications and filter devices usually comprise a main particles filter and a coarse filter arranged upstream side of the main particle filter such that the air flow to be filtered first flows through the coarse filter and then through the main particle filter. The coarse filter is provided to remove at least part of larger particles from the air flow before the main particle filter such that the larger particles do not reach and clog the main particle filter. Thus, the lifetime and efficiency of the main particle filter may be increased and maintained longer periods.

The coarse filter and the main particle filter form a filter construct. The filter construct may also comprise additional filter layers, such electrostatic filter layer(s) arranged to enhance retention of particles as well as one or more other layers, such as protective layers. In some prior art filter constructs one or more filter layers may also comprise adsorbent or catalyst materials, such as charcoal (carbon) for removing odors and gaseous pollutants.

In prior art filter constructs, there may be one or more electrostatically charged filter layers for enhancing filtration efficiency. Such prior art static charge decays over a period of time and the filter loses efficiency.

The disadvantage relating to filter constructs and air cleaning devices is that increasing filtration efficiency such that an increased retention of particles is achieved causes increasing in now resistance through the filter construct or the air cleaning device. The increased filtration efficiency may be achieved for example by increasing thickness of the filter layers or the filter construct or decreasing pore size of the filter materials]. Increased thickness and decreased pore size both increase the flow resistance.

The increased flow resistance compromises air flow through the filter construct and also through the air cleaning device. This makes breathing through a face mask more difficult. Further, the high flow resistance causes high pressure drop across the filter construct and thus power of an air cleaner device needs to be increased for compensating the high flow resistance. The increased power causes more energy consumption and generates more noise. There is a need for providing filter constructs and air cleaner devices with improved filtration efficiency and long lifetime.

BRIEF DESCRIPTION OF THE INVENTION

An object of the present invention is to provide a filter construct and an air cleaner device such that the prior art disadvantages are solved or at least alleviated.

The objects of the invention are achieved by a filter construct which is characterized by what is stated in the independent claim 1. The objects of the invention are further achieved with an air cleaner device according to the independent clam 18.

The preferred embodiments of the invention are disclosed in the dependent claims.

The invention is based on the idea of providing a filter construct having an upstream side and a downstream side, the upstream side being provided to be arranged towards an incoming gas flow. The filter construct comprises a main particulate filter and a coarse filter provided to the upstream side of the main particulate filter. The coarse filter being provided with detonation nanodiamonds.

In some embodiments, the coarse filter is further provided with metal ions or metals.

In the context of this application, the coarse filer preferably is provided with metal ions, elemental metal, or other metal compounds. Below, the coarse filter is defined to be provided with metal ions, but in all embodiments coarse filter may comprise in addition to or instead of metal ions also elemental mental or metal compounds.

Detonation nanodiamond (ND) also referred to as ultrananocrystalline diamond or ultradispersed diamond (UDD) is a unique nanomaterial which is produced by detonation synthesis. The detonation nanodiamonds comprise sp ³ carbon and the non-diamond carbon mainly comprising sp ² carbon species. Sp ² carbon provides and active surface to the diamonds. Functionalization of detonation nanodiamonds is discussed in e.g. WO 2014/174150, WO 2014/191633 and WO 2015/092142.

Sato K. et al. (Advanced Powder Technology 29 (2018) 972-976) discloses cellulose nanofiller/nanodiamond composite films. Positively charged nanodiamonds (ND) and negatively charged cellulose nano fibrils (CNF) are combined in an aqueous solution. Such films are very dense and coating alike in structure.

Detonation nanodiamond particles are commercially available both in their positively charged and negatively charged forms which makes them effective species for making electrostatic layers. The inventors have now surprisingly found that they can be applied also for various filter constructs and filter layers thereof. Detonation nanodiamonds having a high surface charge (zeta potential) are commercially available at brand names uDiamond Hydrogen D (highly zeta positive, hydrogen terminated nanodiamonds in dispersion), uDiamond Vox D (highly zeta negative, carboxylated nanodiamonds in dispersion) or uDiamond Amine D (highly zeta positive nanodiamonds in dispersion).

The small and spherical, highly charged nanodiamond particles applied onto/into the porous coarse filter can form a three-dimensional structure on nanoscale, effective capturing not only the particles, but also bacteria and viruses. The detonation nanodiamond particles provide a non-decaying surface charge which is not affected for example by moisture. The inventors have also found out that when the coarse filter is incorporated with metal ions, the coarse filter is also effective reducing microbes and many viral particles.

Metal ions such as silver and copper ions are known to have antimicrobial activity. WO 2004/024278 discloses an active agent incorporated in the porous dielectric carrier. The active agent may be an antimicrobial or an antitoxin, such as metals including silver and copper.

The present disclosure allows manufacturing coarse filters or electrostatic coarse filters or coarse filter layers capturing either negatively or positively charged species, including particles, bacteria, fungus and viruses. The performance of a filter construct can be tailored by modifying the electrostatic layer detonation nanodiamond concentration and/or the thickness of the filter layer containing the detonation nanodiamond particles.

The detonation nanodiamond particles can be applied to the coarse filter, for example, by drying them from their dispersion form directly onto a fibrous or porous coarse filter material, allowing them located throughout said coarse filter material surfaces. Respectively, metal ions can be applied in the same solution as nanodiamonds. Alternatively, metal ions maybe applied to the coarse filter material using a separate aqueous suspension. This allows applying metal ions independently from detonation nanodiamond, to a same or another surface of the coarse filter material.

Due to nanoscale size of the detonation nanodiamonds and metal ions, and possible complexes of those, the pressure loss caused by the coarse filter will not remarkably be increased but the filtration efficiency is increased. Therefore, providing detonation nanodiamond particles and metal ions to the coarse filter with larger pore size, it is possible to reduce the air flow resistance without compromising on the filter particulate capturing performance. Such a feature allows lower pressure drop in the coarse filter and in the filter construct as whole and thus, lower overall energy consumption in air cleaner devices. Such a feature also allows lower air flow resistance within safety masks, making such a mask more user friendly due to easier breathing. Therefore, for achieving a certain filtration efficiency the pore size of the coarse filter may be increased and the flow resistance decreased.

In the context of the present application, the lower flow resistance through the coarse filter or the filter construct means lower pressure drop over the coarse filter or the filter construct.

Detonation nanodiamonds create active surface to the coarse filter or increase the active surface. They have an ability to capture particles, viruses, bacteria, pollen, allergens and fungus and possibly also at least partially deactivate those. The detonation nanodiamonds may adhered on to the surface of the coarse filter, comprising also the inner surface of the pores. Thus, the detonation nanodiamonds can also be inside, completely or in part, the coarse filter body material matrix. This allows a direct interaction with the foreign particles, viruses and bacteria, and enhances capturing those. The distribution and thus the particle- to-particle distance of the detonation nanodiamond particles may be adjusted by selecting suitable application method. The coarse filter is provided upstream of the main particle filter such that coarse filter captures larger particles before the main particle filter and enables prolonging the lifetime of the main particle filter and decreasing the pressure drop across the filter constructs.

In one embodiment, the coarse filter has a pre-determined filtration efficiency, and the detonation nanodiamonds or the detonation nanodiamonds and metal ions are provided to the coarse filter such that a decreased flow resistance of the coarse filter is achieved with the pre-determined filtration efficiency.

Accordingly, the coarse filter provided with the detonation nanodiamonds or with the detonation nanodiamonds and the metal ions has flow resistance that is smaller than flow resistance of a prior art coarse filter with the same filtration efficiency. Therefore, also the overall flow resistance through the filter construct, comprising the coarse filter and the main filter, is decreased.

In addition to the above mentioned, the detonation nanodiamonds may form arrays to the coarse filter such that flow resistance may be decreased. The arrays, or orderly formed arrays, may provide more laminar flow through the coarse filter so as to at least partly decrease turbulence in the flow.

Further the detonation nanodiamonds and the metal ions, and especially complexes thereof, may form arrays which may provide even more laminar flow through the coarse filer.

In the present application the expression "an outer surface of the filter material" means the outer surface of the sheet or filter material layer excluding the surface of the pores. The term "surface of the filter material" means the whole open surface of the material layer and includes also the (inner) surface of the pores within the material.

In one embodiment, the detonation nanodiamonds or the detonation nanodiamonds and metal ions are provided on a surface of the coarse filter.

The detonation nanodiamonds or the detonation nanodiamonds and the metal ions are incorporated to surfaces of the coarse filter on part of the coarse filter or throughout the coarse filter.

In an alternative embodiment, the coarse filter comprises a first outer surface and a second outer surface on opposite sides of the coarse filter, the second outer surface being arranged towards the main particulate filter. The detonation nanodiamonds or the detonation nanodiamonds and the metal ions are provided on the first outer surface or on the second outer surface of the coarse filter.

In a further alternative embodiment, the coarse filter comprises a first outer surface and a second outer surface on opposite sides of the coarse filter, the second outer surface being arranged towards the main particulate filter. The detonation nanodiamonds or the detonation nanodiamonds and the metal ions are provided on the first outer surface and on the second outer surface of the coarse filter.

In one embodiment, the detonation nanodiamonds or the detonation nanodiamonds and the metal ions are provided on the second outer surface of the coarse filter. Further, the coarse filter is attached to an upstream surface of the main filter such that the detonation nanodiamonds or the detonation nanodiamonds and the metal ions are provided between the coarse filter and the main filter or to the boundary layer between the between the coarse filter and the main filter. Thus, the detonation nanodiamonds or especially the detonation nanodiamonds and the meatal ions may provide the arrays or orderly formed arrays between the coarse filter and the main filter. Therefore, more laminar flow from the coarse filter to the main filter may be generated such that the flow resistance over the whole filter construct is decreased.

It should be noted, that as the coarse filter is made of porous material the detonation nanodiamonds or the detonation nanodiamonds and the metal ions tend to also enter the pores inside the coarse filter material, at least in vicinity of the outer surface. The detonation nanodiamonds or the detonation nanodiamonds and the metal ions may be applied to the coarse filter from the direction of the first and/or second outer surface.

In a further embodiment, the detonation nanodiamonds or the detonation nanodiamonds and the metal ions are embedded throughout the coarse filter. Accordingly, the detonation nanodiamonds or the detonation nanodiamonds and the metal ions are dispersed and incorporated throughout the coarse filter.

Alternatively, the detonation nanodiamonds or the detonation nanodiamonds and the metal ions are provided on the first outer surface or on the second outer surface of the coarse filter and embedded into the coarse filter. Thus, the detonation nanodiamonds or the detonation nanodiamonds and the metal ions may be applied to the coarse filter from the direction of the first or second outer surface.

Alternatively, the detonation nanodiamonds or the detonation nanodiamonds and the metal ions are provided on the first outer surface and on the second outer surface of the coarse filter and embedded between the first outer surface and the second outer surface of the coarse filter. Thus, the detonation nanodiamonds or the detonation nanodiamonds and the metal ions may be applied to the coarse filter from the direction of the first and second outer surface, or the coarse filter may be impregnated with a solution comprising the detonation nanodiamonds or the detonation nanodiamonds and the metal ions.

A generally uniform distribution or concentration of detonation nanodiamonds or the detonation nanodiamonds and the metal ions in the coarse filter is preferred uniform properties, especially in direction of the outer surfaces.

In one embodiment, the main filter comprises an upstream surface and a downstream surface on opposite sides of the main particulate filter. The upstream surface is arranged towards the upstream side of the filter construct. The coarse filter comprises the first outer surface and the second outer surface on opposite sides of the coarse filter. The second outer surface of the coarse filter is arranged towards the upstream surface of the main particulate filter.

The second outer surface of the coarse filter is arranged on the upstream surface of the main particulate filter. Thus, the coarse filter is provided directly upstream of the main particulate filter. The flow resistance may thus be minimized.

Preferably, the coarse filter is attached on the main filter. Thus, the second surface of the coarse filter is attached to the upstream surface of the main filter. In some embodiments, the coarse filter is melted to the main filter, or the second surface of the coarse filter is melted on the upstream surface of the main filter. Tight attachment of the coarse filter to the main filter prevents gas escaping the filter construct between the coarse filter and the main filter.

Alternatively, the second outer surface of the coarse filter is arranged towards the upstream surface of the main particulate filter, and one or more intermediate filter layers are provided between the second outer surface of the coarse filter being arranged towards the upstream surface of the main particulate filter.

This enables providing special intermediate filter layers between the coarse filter and the main particulate filter such that coarse particles may be removed upstream of the special intermediate filter layer. The intermediate filter layer may be for example a separate electrostatic filter layer or protective layer or a combination thereof.

Further, in some embodiments the filter construct further comprises one or more pre-filter layers arranged on or upstream of the first outer surface of the coarse filter. The pre-filter layers may be comprise protective filter layer(s) or the like.

In some embodiments, the coarse filter is made of fibrous or fiber based material or non-woven material. Alternatively, the coarse filter is made of some other porous material.

In some embodiments, the coarse filter is made of or essentially made of polyethylene terephthalate (PET).

In some embodiments, for example in face masks or respirators, the coarse filter is made of one or more PET sub-layers. The PET sub-layer forming the second surface of the coarse filter may be melted or attached to the main filter. The face mask or a respirator may comprise also other layers such as polypropylene based hydrophobic non-woven fabric on upstream side and polypropylene base skin-friendly non-woven fabric facing the user face. The face mask or a respirator may further comprise additional filter layers made from but not limited to melt- blown, static polypropylene or Hot Air Cotton.

In the above embodiment, the PET sub-layer forming the second surface of the coarse filter may be melted or attached to the main filter.

In face masks or respirators, the microbes, viruses or the like are preferably eliminated on upstream side and downstream side of the filter construct. Thus, there may be coarse filter on both sides of the main filter.

In this application the term "coarse filter material" means the coarse filter material before incorporating detonation nanodiamonds or the detonation nanodiamonds and the metal ions. The material may be a mechanical filter without electrostatic charge, it may be charged, it may be functionalized, or it may comprise incorporated active agents such as charcoal. The coarse filter material can be natural polymer based or a synthetic material such as a polymer or a mixture of polymers. The coarse filter material can also be ceramic material or some other suitable material.

The coarse filter material has a continuous porosity. In this context the term continuous porosity means open porosity allowing gas flow through the porous layers. The pores or series of pores form a tubular open-ended structure elongating from the first outer surface of the coarse filter to the second outer surface of the coarse filter. In this connection the free space within the coarse filter material are referred as "pores". The pore size can vary from 100 nm to 30 micrometers and the diameter of a pore can vary throughout the pore structure.

Coarse filter material may be composed of a mat of randomly arranged fibres or any other porous material such as ceramic of metallic structure. The fibrous material may comprise a synthetic or natural polymer such as nylon, polyethylene, polypropylene, polyester, glass fibre or any cellulosic fibre. The fibrous material is typically a mixture of various polymers, one such representative being marketed as "ES Fiber Cotton".

Another typical representative example of the coarse filter material is PET based G4 class filters applied as coarse filters in filter constructs. The other representative examples are PET or any other coarse filter materials are based Gl, G2, G3, or alternatively M5, M6, F7, F8, F9.

Thickness of coarse filter may be varied. Typical polymer-based may have weight per m ² of 30 to 300 g/m ² . Preferably, the weight of the coarse filter is between 100 to 200 g/m ² , more preferably 120 to 180 g/m ² . When the base material is metal, the weight per m ² will obviously be higher.

The pores can also be manufactured by needle punching, a typical method producing "needle punched nylon" applied widely for example within safety masks. The metal and ceramic based coarse filter structures are typically manufactured by sintering selected sized metal or ceramic particles to form a filter structure.

When applying detonation nanodiamonds or the detonation nanodiamonds and the metal ions particles on either metallic or ceramic filter structure, such coarse filters can be re-activated by washing away the trapped species and nanodiamonds, followed by re-introducing a new load of detonation nanodiamonds or the detonation nanodiamonds and the metal ions particles coarse filter pores and surfaces.

Accordingly, in some embodiments the coarse filter is provided or attached to the filter construct or to the main particle filter as removable or replaceable.

Nonwoven fiber layers or mats may have a very high proportion of void volume. Non-woven fibrous filter media are formed by the random distribution of fibers in a specific space exhibit a complicated pore size structure.

Accordingly, in some embodiments the coarse filter is made of fiber or fibrous based material or non-woven material.

In one embodiment, the coarse filter has filtration efficiency of at least 10% of particles with diameter 0.3 gm or more.

In another embodiment, the coarse filter has filtration efficiency of at least 20% of particles with diameter 0.3 gm or more.

In a further embodiment, the coarse filter having filtration efficiency of at least 40% of particles with diameter 0.3 m or more.

Higher filtration efficiency tends to increase the flow resistance.

The coarse filter may belong to class Gl, G2, G3 or G4 under European normalization standards EN 779.

Alternatively, the coarse filter may belong to class M5, M6, F7, F8 and F9 under European normalization standards EN 779.

The detonation nanodiamonds or the detonation nanodiamonds and the metal ions enable providing the coarse filter of the present invention with lower flow resistance without compromising the filtration efficiency.

In some embodiments, the main particulate filter is a high efficiency particulate air (HEPA) filter or an ultra low particulate air (ULPA) filter.

The HEPA filter used as the main particulate filter may belong to class E10, Ell, E12, H13 or H14 under European normalization standards EN 779.

In the present invention, the main particle filter may be any kind of known HEPA or ULPA filter.

In some embodiments, the main particulate filter is made of polytetrafluoroethylene (PTFE) based material or expanded polytetrafluoroethylene (ePTFE) based material.

In some embodiments of a face mask or respirator, the coarse filter may be made from PET -material and the main filter from ePTFE or PTFE. The coarse filter is further provided with the detonation nanodiamonds or with the detonation nanodiamonds and the metal ions.

Accordingly, some embodiments the main filter has filtration efficiency of at least 85% of particles with diameter 0.3 pm or more.

In alternative embodiments, the main filter has filtration efficiency of at least 95% of particles with diameter 0.3 pm or more.

In further alternative embodiments, the main filter has filtration efficiency of at least 99.95% of particles with diameter 0.3 pm or more.

In some embodiments, the coarse filter comprises detonation nanodiamonds an amount of 0.001 to 100 g/m ² calculated based on the outer surface of the coarse filter.

In alternative embodiments, the coarse filter comprises detonation nanodiamonds an amount of 0.01 to 100 g/m ² calculated based on the outer surface of the coarse filter.

In a further alternative embodiment, the coarse filter comprises detonation nanodiamonds an amount of 0.001 to 10 g/m ² calculated based on the outer surface of the coarse.

In some embodiments, the coarse filter comprises metal ions an amount of 0.01 to 100 g/m ² calculated based on the outer surface of the coarse filter.

Further, the total amount of detonation nanodiamonds and metal ions is 0.05 to 1.0 wt.-% of the total weight of coarse filter, in some embodiments o the present invention.

The low amount of detonation nanodiamonds and metal ions does not affect weight of the coarse filter or bendability properties.

In some embodiments, the detonation nanodiamonds have zeta potential of at least +40 mV or less than -40 mV, or preferably at least +50 mV or less than -50 mV. Further, in alternative embodiments, the detonation nanodiamonds have surface charge of at least +55 mV or less than -55 mV.

It should be noted that less than - 40mV, or less than -50 mV or less than - 55 mV means zeta potential for example -70 mV.

A filter construct can be designed to comprise either one coarse filter capturing oppositely charged species or two oppositely charged coarse filters layers capturing both negatively and positively charged species.

Accordingly, in the embodiments of the present invention the filter construct may comprise one or to more even two or more coarse filters according to the present invention upstream of the main particulate filter.

The detonation nanodiamond zeta potential may be measured of nanodiamonds diluted to 0.1 wt.-% aqueous dispersion using Malvern Zetasizer NanoZS according to manufacturer’s instructions. The detonation nanodiamond particle size distributions may be measured of samples diluted to 0.5 wt.-%.

In some embodiments, the detonation nanodiamonds have an average primary particle diameter of 4 to 6 nm.

Providing a dispersion and using 4-6 nm detonation nanodiamond particles and the metal ions in their dispersion form allows also their even spread and adhesion throughout the complex, fine sized porous structure.

The detonation nanodiamonds may have an average primary particle diameter of 4 to 6 nm. Nanoscale size increases the active, highly charged area and provide their good adhesion to the filter layer base material. In addition, detonation nanodiamonds do not substantially lower the gas flow throughout the filter layer. They are not detached as subjected to airflow.

The detonation nanodiamonds may be single digit detonation nanodiamonds. Single digit nanodiamonds provide a large active surface and do not aggregate. In addition, they have a minimal effect to the air flow properties of the filter layer. By term "single digit nanodiamond" is meant a nanodiamond particle substantially in its primary particle form. The average size of a single digit nanodiamond particle is 10 nm or less.

In the present invention, examples suitable metal ions of the coarse filter may comprise metal ions such as aluminum, barium, boron, calcium, chromium, copper, iron, magnesium, manganese, molybdenum, nickel, potassium, sodium, strontium, zinc and silver.

In one embodiment the coarse filter layer comprises metal ions of copper, silver, zinc or any mixture thereof.

Metal ions can be applied in form of salts. In filter layer they may be at least in form of complex with detonation nanodiamond or in salt form or attached as ions to the charged filter matrix. The metals can also be present as metallic nanoparticles. The salt may be any non-harmful salt such as sulphate, nitrate, chloride or e.g. salts of organic compound (e.g. citrate, oxalate).

The present invention further is based on the idea of providing an air cleaner device having an inlet side for receiving incoming gas flow. The air cleaner device comprises a filter construct for filtering particulate matter. The filter construct comprises a coarse filter for coarse filtering the incoming gas flow, and a main particulate filter with filtration efficiency of at least 85% of particles with diameter 0.3 gm or more. The main particulate filter being arranged downstream of the coarse filter in relation to the incoming gas flow from the inlet side for removing contaminants from the coarse filtered incoming gas flow. The coarse filter is provided with detonation nanodiamonds.

In some embodiments, the coarse filter is further provided with metal ions.

The detonation nanodiamonds or the detonation nanodiamonds and the metal ions enable increasing filtration efficiency of the coarse filter without increasing flow resistance. Thus, a coarse filter with lower flow resistance may be provided to the air cleaner device such that the flow resistance across the air cleaner device is lowered.

In some embodiments, the air cleaner device comprises a predetermined device filtration efficiency, and that the detonation nanodiamonds or the detonation nanodiamonds and the metal ions are provided to the coarse filter such that a decreased flow resistance of the air cleaner device is achieved with the pre-determined device filtration efficiency. In one embodiment, the coarse filter and the main particulate filter are provided in the air filter device to a filter construct forming one filter construct unit.

In an alternative embodiment, the coarse filter and the main particulate filter are provided in the air filter device to the filter construct as separate filter layers, and the coarse filter and the main particulate filter are arranged spaced apart from each other in the filter construct.

The filter construct of the air cleaner device is a filter construct as disclosed above.

The air cleaner device comprises a frame, and the coarse filter and the main particulate filter or the filter construct is supported to the frame. The frame provides structural support for the filter construct.

Accordingly, in some embodiments the air cleaner device is a face mask, or alternatively the air cleaner device is a safety cloth or safety curtain.

In alternative embodiments, the air cleaner device is an air purifier.

The air purifier comprises a flow channel between the inlet side and an outlet side of the air purifier. The coarse filter and the main particulate filter or the filter construct is arranged to flow channel of the air purifier for removing contaminant from the air flow flowing through the flow channel.

In some embodiments, the coarse filter is provided or arranged removable or replaceable to the air cleaner device.

Alternatively, the coarse filter is provided or arranged removable or replaceable to the filter construct.

Removable or replaceable coarse filter enables changing or washing the coarse filter for maintaining filtration efficiency and preventing flow resistance from increasing excessively.

An advantage of the invention is that a coarse filter with decreased flow resistance may be provided upstream of the main particulate filter. Thus, lowered energy consumption and lower noise may be achieved without compromising filtration efficiency. Further, user friendly face mask though which it is easier to breath may be formed.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described in detail by means of specific embodiments with reference to the enclosed drawings, in which

Figures 1 and 2 show schematically one embodiment of a filter construct according to the present invention;

Figure 3 shows schematically one embodiment of an air cleaner device according to the present invention;

Figure 4 shows schematically another embodiment of a filter construct according to the present invention; and

Figures 5 to 9 show schematically different embodiment of an air cleaner device according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 shows a schematic view of a filter construct 10. An incoming gas flow A flowing to the filter construct 10 is shown with arrow A. The incoming gas flow A passes through the filter construct 10 and becomes outgoing gas flow B shown with arrow B. The outgoing gas flow is filtered with the filter construct 10 such that contaminants are removed from the incoming gas flow A and the filtered outgoing gas flow B is generated.

The filter construct 10 comprises a main particulate filter 30 arranged to remove particulates from the gas flow. The main particulate filter 30 is HEPA or ULPA filter, as discussed above. Alternatively, the main particulate filter 30 may be any know particulate filter having filtration efficiency of at least 85%, preferably at least 95% or more preferably at least 99,95% of particles with diameter 0.3 gm or more.

The main particulate filter 30 comprises an upstream surface 32 arranged or provided to be arranged towards the incoming gas flow A and to the upstream side of the main particulate filter 30. The main particulate filter 30 also comprises a downstream surface 34 arranged or provided to be arranged away from the incoming gas flow A and downstream side of the main particulate filter 30.

The filter construct 10 further comprises a coarse filter 20 arranged to remove particulates from the incoming gas flow A. The coarse filter 20 is arranged upstream of the main particulate filter 30. Thus, the coarse filter 20 is arranged to remove particles from the incoming gas flow A upstream of the main particulate filter 30. The coarse filter 20 is arranged on the upstream surface 32 of the main particulate filter 30 or on the side of the upstream surface 32 of the main particulate filter 30.

The coarse filter 20 comprises a first outer surface 22 arranged or provided to be arranged towards the incoming gas flow A and to the upstream side of the coarse filter 20. The coarse filter 20 also comprises a second outer surface 24 arranged or provided to be arranged away from the incoming gas flow A and downstream side of the coarse filter 20.

According to the present invention, the coarse filter 20 is provided, incorporated, or embedded with detonation nanodiamonds or detonation nanodiamonds and metal ions, as described above.

The detonation nanodiamonds or the detonation nanodiamonds and the metal ions may be attached or adhered to the first and/or second outer surface 22, 24, or in surfaces including the inner pore surfaces of the coarse filter 20.

Accordingly, the coarse filter 20 is arranged in the filter construct upstream side of the main particulate filter 30 such that the incoming gas flow A flows first through the coarse filter 20 and then to the main particulate filter 30.

Thus, the second outer surface 24 of the coarse filter 20 is arranged towards the upstream surface 32 of the main particulate filter 30.

Figure 2 shows an embodiment in which the coarse filter 20 and the main particulate filter 30 of the filter construct 10 form a filter construct unit 50. In this embodiment, the coarse filter 20 is arranged directly upstream of the main particulate filter 30.

The coarse filter 20 is arranged on the upstream surface 32 of the main particulate filter 30. Thus, the second outer surface 24 of the coarse filter 20 is arranged on or against the upstream surface 32 of the main particulate filter 30.

The coarse filter 20 is preferably attached or melted to the main filter 30. Thus, the second surface 24 o the coarse filter 20 is melted or attached to the upstream surface 32 of the main filter 30. Further, the detonation nanodiamonds or the detonation nanodiamonds and the metal ions may be provided on the second outer surface 24.

Alternative, the coarse filter 20 is arranged in front of the upstream surface 32 of the main particulate filter 30 or spaced apart from the upstream surface 32.

The filter construct 10 or the filter construct unit 50 comprises an upstream side 12 arranged or provided to be arranged towards the incoming gas flow A. The filter construct 10 or the filter construct unit 50 further comprises a downstream side 14 arranged or provided to the arranged away from the incoming gas flow A.

In the embodiment of figure 2, the first outer surface 22 of the coarse filter 20 is arranged to form the upstream side 12 of the filter construct 10 or the filter construct unit 50. Similarly, the downstream surface 34 of the main particulate filter 30 is arranged to form the downstream side 14 of the filter construct 10 or the filter construct unit 50.

The coarse filter 20 may attached to the main particulate filter 30. Alternatively, the coarse filter 20 may a separate filter layer and separate from the main particulate filter 30.

It should be noted, that the filter construct 10 and the filter construct unit 50 of figure 2 may be provided with one or more pre-filter layers (not shown) on the upstream side or on the first outer surface 22 of the coarse filter 20. Similarly or additionally, the filter construct 10 and the filter construct unit 50 of figure 2 may also be provided with one or more post-filter layers (not shown) on the downstream side or on the downstream surface 34 of the main particulate filter 30. Thus, the pre-filter layers may form the upstream side 12 of the filter construct 10 or the filter construct unit 50, and/or the post-filter layers may form the downstream side 14 of the filter construct 10 or the filter construct unit 50.

Figure 3 shows filter construct 10 comprising the filter construct unit 50 of figure 2. The filter construct 10 further comprises a construct frame 2 or body. The coarse filter 20 and the main particulate filter 30 are supported to the frame 2. The frame 2 provides rigidity to the filter construct 10.

The filter construct unit 50 may be supported to the frame 2. Alternatively, the coarse filter 20 and the main particulate filter 30 are separately or together supported to the frame 2. Further alternatively, the coarse filter 20 is supported to the frame 2 via the main particulate filter 30, or the main particulate filter 30 is supported to the frame 2 via the coarse filter 20.

The filter construct unit 50, or the coarse filter 20 and the main filter 30, are sealed or secured to frame 2 in air-tight manner such that gas passing the filter construct unit 50, or the coarse filter 20 and the main filter 30 may be prevented.

In some embodiments, the filter construct 10 comprising the frame 2 is arranged to form an air cleaner device, such as face mask or an air purifier.

Figure 4 shows an alternative embodiment of the filter construct 10. In this embodiment, the filter construct 10 is provided with a pre-filter layer 42 arranged on the first outer surface 22 or on the upstream side of the coarse filter 20. The pre-filter 42 may be for example a protective layer arranged to protect the coarse filter 20.

The filter construct 10 is further provided with an intermediate filter layer 44 arranged between the coarse filter 20 and the main particulate filter 30. The intermediate filter layer 44 may be for example an electrostatic filter layer.

Accordingly, the intermediate filter layer 44 is arranged between the second outer surface 24 of the coarse filter 20 and the upstream surface 32 of the main particulate filter 30.

The intermediate filter layer 44 may be attached to the second outer surface 24 of the coarse filter 20 and/or the upstream surface 32 of the main particulate filter 30, or provided as a separate filter layer.

In this embodiment, the pre-filter layer 42, the coarse filter 20, the intermediate filter layer 44 and the main particulate filter 30 form the filter construct unit 50.

It should be noted, that the pre-filter layer 42 or the intermediate filter layer 44 may also be omitted.

Furthermore, it should be noted that in the present invention the filter construct 10 may also comprise one or more, or two or more coarse filter 20 according to the present invention on the upstream side of the main particulate filter 30.

The coarse filter 20, the main filter 30 and the possible other filter layers 42, 44 are preferably attached to each other or sealed to the frame 2 in airtight manner for preventing escaping of gas.

Figure 5 shows an embodiment in which the filter construct 10 is arranged to flow duct 120, which may be for example a ventilation duct. The flow duct 120 comprises a flow channel 122 and the filter construct according to the present invention is arranged into the flow channel 122 for filtering the air or gas flowing in the flow duct 120.

The filter construct 10 comprises the frame 2. The frame 2 and the filter construct together form an air cleaner device 1.

The air cleaner device 1 or the frame 2 comprises an inlet side 5 which arranged to receive the incoming gas flow A into the air cleaner device 1. The inlet side 5 is arranged or provided to be arranged in upstream direction or towards the incoming gas flow A. The frame 2 may comprise on the inlet side 5 one or more inlet openings via which the incoming gas flow A enters or is received into the air cleaner device 1.

The air cleaner device 1 or the frame 2 also comprises an outlet side 6 which arranged to discharge the outgoing gas flow B from the air cleaner device 1. The outlet side 6 is arranged or provided to be arranged in downstream direction or away from the incoming gas flow A. The frame 2 may comprise on the outlet side 6 one or more outlet openings via which the outgoing gas now B leaves or is discharged from the air cleaner device 1.

The coarse filter 20 is on the inlet side 5 and between the inlet side 5 and the main particle filter 30. The main particle filter 30 is on the outlet side 6 and between the coarse filter 20 and the outlet side 6.

The frame 2 comprises a frame flow channel 3 extending between the inlet side 5 and the outlet side 6. The filter construct 10 or the coarse filter 20 and the main particulate filter 30 are provided to the frame flow channel 3 between the inlet side 5 and the outlet side 6.

The filter construct, or the coarse filter 20, the main filter 30 and the possible other filter layers 42, 44 are preferably attached or sealed to the frame flow channel 3 in the frame 2 in air-tight manner.

Figure 6 shows one embodiment of an air cleaner device 1. The air cleaner device 1 comprises the frame 2 having the inlet side 5 with one or more inlet openings and the outlet side with one or more outlet openings. The frame 2 comprises the frame flow channel 3 extending between the inlet side 5 and the outlet side 6. The air cleaner device 1 further comprises a flow generator 4 for generating air flow A, B through air cleaner device 1. Thus, the flow generator 4 generates the incoming gas flow A and further the outgoing gas flow B.

The flow generator 4 may be a fan or a pump, or the like connected to a power source. In the embodiment of figure 6, the coarse filter 20 is arranged upstream of the flow generator 4 and the main particle filter 30. The coarse filter 20 is arranged between the inlet side 5 and the flow generator 4. The main particle filter 30 is arranged downstream of the flow generator 4 and the coarse filter 20. The main particle filter 30 is arranged between the flow generator 4 and the outlet side 6. Thus, the flow generator 4 is arranged between the coarse filter 20 and the main particulate filter 30. Thus, the coarse filter 20 and the main particle filter 30 are arranged spaced apart from each other in the frame 2.

Figure 7 shows an alternative embodiment, in which the flow generator 4 is arranged upstream of the coarse filter 20 and the main particulate filter 30. Thus, the flow generator 4 is arranged between the inlet side 5 and the coarse filter 20 o the filter construct 10.

In this embodiment, the air cleaner device 1 further comprises screen 40 provided upstream of the flow generator 4, or between the inlet side 5 and the flow generator 4. The screen removes larger contaminants from the incoming gas flow A for protecting the flow generator 4. Further, the coarse filter 20 and the main particle filter 30 are provided in the filter construct unit together.

It should be noted, that the flow generator 4 may also be arranged downstream of the main particulate filter 30, or between the main particulate filter 30 and the outlet side 6.

Figure 8 shows an embodiment of an air cleaner device which is a face mask 100. The face mask 100 comprises a mask part 102 and string parts 107, 108 for placing the face mask 100 on a user.

The mask part comprises a mask frame 104 and a filter construct 10 according to the present invention. The filter construct 10 is supported to the mask frame 104.

The string parts 107, 108 are attached to the mask frame 104.

Figure 9 shows a side view of the face mask 100. The face mask 100 has an inlet side 105 for receiving incoming gas A, and an outlet side 106 on opposite side of the filter construct 10.

The mask frame 104 may define the inlet side 105 and the outlet side 106.

The filter construct 10 is a filter construct according to the present invention. The filter construct comprises the main particulate filter 30, and coarse filter 20 provided to the upstream side 12 of the main particulate filter 30 and on the inlet side 105. The coarse filter 20 is provided with detonation nanodiamonds metal ions.

The face mask may be a surgical mask. Preferably, the face mask may be an N95 respirator that is a particulate-filtering face mask respirator that meets the U.S. National Institute for Occupational Safety and Health (NIOSH) N95 classification of air filtration, meaning that it filters at least 95% of airborne particles. Alternatively, the face mask may be an N99 mask or N99 respirator that is a particulate-filtering face mask respirator that meets the U.S. National Institute for Occupational Safety and Health (NIOSH) N95 classification of air filtration, meaning that it filters at least 99% of airborne particles. N95 respirators are considered functionally equivalent to certain respirators regulated under non-U. S. jurisdictions, such as FFP2 respirators of the European Union and KN95 respirators of China. N99 respirators are considered functionally equivalent to certain respirators regulated under non-U. S. jurisdictions, such as FFP3 respirators of the European Union and KN99 respirators of China.

The invention has been described above with reference to the examples shown in the figures. However, the invention is in no way restricted to the above examples but may vary within the scope of the claims.