Room air purifier with low pressure filter

Abstract

The present invention relates to a filter device (100) for filtering air (103) in a room (200) of a building. The filter device (100) has a filter medium (101) and a fan unit (102), wherein air (103) to be filtered can flow through the filter medium (101) for filtering by means of the fan unit (102). A filter surface of the filter medium (101) is five times larger than a smallest air flow cross-section in the fan unit (102) such that an air flow angle (104) between the flow direction of the air (103) when the air enters the filter into the filter medium (101) and a filter surface of the filter medium (101) differs from 90 degrees, and the sound pressure level of the filter device (100) at a meter distance from the filter device (100) at a volume flow above 50 m3 / h of the air (103) driven by the fan unit (102) is below 48 dB, wherein the filter medium (101) is configured in such a way that the pressure drop of the air (103) flowing through the filter medium (101) is less than 450 pascals.

Description

[0001] Room air purifier with low-pressure filter

[0002] Technical area

[0003] The present invention relates to a filter device for filtering air in a room of a building and a method for filtering air in a room of a building with a filter device.

[0004] Background of the invention

[0005] Filter systems in air conditioning systems ensure the ventilation and de-aeration of rooms within buildings and filter pollutants from the air. Primary filter systems are used in buildings, for example, central ventilation systems within a building and controlled apartment ventilation systems. The primary filter systems may have a connection to the outside air. Secondary filter systems are often used to supplement the primary filter systems. A secondary filter system, for example, includes an air circulation system with filtration and is designed for installation in a room (e.g., an air purifier).

[0006] Secondary filter systems for air purification often have a lower air throughput than the primary ventilation systems, meaning that aerosols in the air, for example, cannot be filtered sufficiently to reduce any viral contamination in the contaminated room air to a sufficiently low level in a sufficiently short time. The aerosols exhaled by people pollute the room air and pose a risk of infection to other people present. More powerful secondary ventilation systems, on the other hand, are often loud, which is something that the occupants in the room find disturbing. This particularly applies to offices, event halls, meeting rooms and training rooms with a high occupancy of people per square meter. In order to achieve effective aerosol depletion in such environments, the required air turnover increases more than linearly, which also causes the associated acoustic pollution to rise exponentially.

[0007] It is an object of the present invention to provide a filter device with high performance and low operating noise.

[0008] According to a first aspect of the present invention, a filter device for filtering air in a room of a building is described. The filter device comprises a filter medium and a fan unit, wherein air to be filtered can be flowed through the filter medium for filtering by means of the fan unit. A filter surface of the filter medium is five times larger than a smallest air flow cross-section in the fan unit, such that an air flow angle between the flow direction of the air at the filter entry into the filter medium and a filter surface of the filter medium differs from 90 degrees, and the sound pressure level of the filter device at a distance of one meter from the filter device at a volume flow of over 50 m 3 / h of the air driven by the fan unit is below 48 dB, wherein the filter medium is configured such that the pressure drop of the air flowing through the filter medium is less than 450 Pascal.

[0009] According to a further aspect, a method for filtering air in a room of a building using a filter device as described above is shown. A filter device according to the invention is typically used in buildings for filtering and purifying air or for purifying air in production processes in factories.

[0010] The filter device comprises, for example, a housing in which a filter medium is arranged, or a plurality of filter media are arranged in series along the direction of air flow through the filter device or parallel to the flow direction. The filter medium can be designed to be replaceable.

[0011] The filter medium of the filter device comprises, for example, a flat filter material that is fixed in a circumferential support frame. The filter medium can be designed as a pocket filter, with a plurality of pockets of filter medium being attached to the support frame, and the air flow being directed into the pockets to filter the incoming air. Furthermore, the filter medium can also be designed as a cartridge filter, bag filter, candle filter, compact filter, and HEPA filter.

[0012] The fan unit of the filter device draws air to be filtered into the filter device, causing the air to flow through the filter medium. The fan unit can, for example, have an axial or radial compressor and, accordingly, flow the air along a translational flow in a straight line or at right angles. The fan unit can, in particular, be controlled by the control unit, allowing the air flow through the filter device to be adjusted. The fan unit is, in particular, a secondary air circulation system with filtration for installation in a room (a "room air purifier," so to speak). The filter device can be mobile or stationary.

[0013] According to the invention, the filter surface of the filter medium is at least five times larger than the smallest airflow cross-section in the fan unit. The smallest airflow cross-section describes the smallest flow cross-section in the air path through the filter device, i.e., between the air inlet and the air outlet into and out of the filter device. The smallest flow cross-section can be present, for example, in an air duct of the filter device in which a flow-generating element (e.g., a fan) of the fan unit is arranged.

[0014] The filter medium is located downstream of the smallest airflow cross-section. Between the smallest airflow cross-section and the filter medium, the airflow cross-section of the air path through the filter device expands, so that the air encounters a filter medium with a filter area five times larger than the smallest airflow cross-section in the fan unit. Alternatively, the filter medium can also be installed upstream of the fan, meaning the system operates in suction mode. This has the advantage that the fan becomes less contaminated and the air inlet is better soundproofed, allowing it to be positioned closer to a person's head without increasing noise emissions.

[0015] Between the filter medium and the smallest air flow cross-section there is only an expansion of the air flow path, so that a linear portion of the air flow against the filter medium at the filter inlet has a flow direction different from 90 degrees to a filter surface of the filter medium. In particular, the filter surface is parallel to the smallest air flow cross-section or parallel to an air flow cross-section before the expansion of the air flow path begins. In other words, a first air flow cross-section of an expansion region of the air path is parallel to a further air flow cross-section formed downstream of the expansion region, at which the filter surface of the filter medium is present. The expansion region also forms a long relaxation zone without, for example, hard transitions after the fan. Particularly good results have been found when the relaxation zone is larger orlonger than the cross-section of the air flow, in particular more than twice or even four times the cross-section of the air flow.

[0016] This widening ensures that the airflow direction at the filter surface at an angle different from 90 degrees when entering the filter. This applies in particular to 95%, and especially 99%, of the air flow that flows against the filter surface.

[0017] If the airflow is designed such that the main airflow direction at the filter surface at the inlet of the filter medium is not directed in a straight line through the filter medium, but rather is first deflected, for example, by more than 10 degrees, a rotational movement is initiated, particularly for larger particle or aerosol fractions in the air, which achieves a better separation rate on a filter (particularly in combination with multi-layer pore filters and the cyclone separation effect). The cyclone separation effect allows for more stable binding of the contaminants. The inertial movement of heavier airflow components achieved by the air deflection leads to better adhesion to the filter material in the filter medium and thus a better separation rate.

[0018] By means of this widening of the flow cross-section, it is achieved that the sound pressure level of the filter device at a distance of one meter from the filter device (in particular from the air outlet and / or the air inlet of the filter device) at a volume flow of more than 50 m 3 / h of the air driven by the fan unit is below 48 dB. The filter medium is configured in such a way (for example, via the material / pore density, the material selection, and / or the thickness of the filter medium) that the pressure drop (between inlet into the filter medium and outlet from the filter medium) of the air flowing through the filter medium is less than 450 Pascal. The filter performance of the filter device according to the invention, in particular of the filter medium, is measured, for example, according to EN ISO 16890, and is better than 50% for one of the classes "ISO Coarse," "ISO ePM10," "ISO ePM2.5," or "ISO ePM1."

[0019] A reduction in pressure drop is thus achieved through the filter medium and its generously dimensioned filter surface and structure. A high air flow rate causes virus-laden aerosols to initially deposit on the filter medium, but are then quickly dried by the high airflow. This causes enveloped viruses, in particular, to die very quickly as they dry out.

[0020] If the filter surface is larger, especially significantly larger, than the inlet cross-section or the airflow cross-section in the fan unit of the air to be cleaned, this also results in a change in the speed of the airflow. Highly accelerated heavy solid particles (or aerosols) reduce their speed more slowly than light air molecules. This means that they impact the filter membrane relatively forcefully, which in turn leads to good adhesion to the filter (and thus to particularly good depletion). It has been shown that good sound values ​​are possible if the filter surface is more than 5 times larger, in particular more than 10 times larger, in particular more than 20 times larger, and preferably more than 40 times larger, than the smallest airflow cross-section in the fan unit. A corresponding increase in the filter surface leads to a further reduction in the noise level of the flowing air and to improved filter performance.According to a further exemplary embodiment, the filter medium has an (absolute) filter area greater than 1 m. 2 , especially larger than 2 m 2 , especially larger than 4 m 2 , especially larger than 8 m 2 The filter area is the area of ​​the filter medium through which the air flows. For example, the filter area on the upstream side of the filter medium is the same size as the filter area on the downstream side of the filter medium.

[0021] The filter device, in particular, has an outlet opening through which the filtered air can flow out. The filter medium can be arranged in the filter device in such a way that the filter surface can be visually perceived from outside the filter device. In other words, the filter surface is freely accessible from the outside without any noise-generating flow obstructions for the outflowing air.

[0022] With such a large filter surface area of ​​the filter medium, a diffuser for the sound generated by the air flow becomes larger. Furthermore, due to its size, the large filter surface has filter areas that can be located farther from a person's ear, so that the filter areas are then farther away from the ear of the acoustic discomfort and lead to an overall lower perceptible sound level. Together with the design of the dimensions of the filter medium and the configuration of the filter medium with regard to the pressure drop of the air flowing through it (for example, through the material selection and the thickness of the filter medium), the invention describes technical measures that lead to high filter performance with a low noise level.

[0023] A filter surface designed in this way can contain and / or be designed accordingly with stabilizing, fastening, or stiffening components on the inside or outside (such as a support frame, a retaining rail into which the filter medium can be inserted, or a plastic strip connected to the filter for fastening). This counteracts oscillation or vibration of the filter medium in the flowing air and thus indirectly reduces noise.

[0024] The present invention relates in particular to a secondary filter system which, due to a filter medium with a particularly low pressure drop, makes it possible to filter large air volumes with low, low noise emissions and, in particular, to achieve a relevant depletion of aerosols.

[0025] According to a further exemplary embodiment, the filter surface of the filter medium is designed to be larger than a smallest air flow cross-section in the fan unit such that at a distance of one meter the sound pressure level of the filter device is below 45 dB, in particular below 38 dB, in particular below 32 dB, further in particular below 28 dB.

[0026] According to a further exemplary embodiment, the filter medium is designed such that a pressure drop of the air flowing through the filter medium is below 250 Pa, in particular below 150 Pa, further in particular below 70 Pa or 30 Pa.

[0027] According to a further exemplary embodiment, the filter device is configured such that an air volume per hour and square meter of filter area (ie the filter area load) is below 600 m 3 / (m 2 xh), especially below 140 m 3 / (m 2 xh), under 85 m 3 / (m 2 xh) or less than 50 m3 / (m 2xh), and / or the speed of the volume flow of the air (103) through the filter device (100) is in the range 0.1 to 5 m / s, in particular in the range 0.2 m / s to 3.4 m / s, more particularly between 0.3 m / s and 2.8 m / s. These characteristic values ​​can be adjusted in particular by selecting the filter size, the filter material and the design of the fan unit. According to a further exemplary embodiment, the filter device has a microphone unit and a sound generator, wherein the microphone unit is arranged to measure the sound level of the air upstream of the fan unit and / or downstream of the filter medium, wherein the sound generator is configured to generate counter-sound based on the measured sound level. Active noise suppression can thus be integrated.The sound generator generates sound that is tuned to cause destructive interference with the sound generated by the airflow. A counter-signal is also generated that corresponds to the interfering sound but has the opposite polarity. The sound generator thus generates counter-sound based on the airflow sound picked up by the microphone unit, or modulates it. This has the advantage that the sound generator, as the sound source, implicitly masks the airflow noise.

[0028] According to a further exemplary embodiment, the filter device, e.g. its housing, has an air outlet for blowing out the air, wherein the filter device is designed such that the air outlet is lower than 1 m, in particular lower than 0.5 m, above the floor (or the surface on which the filter device rests). Additionally or alternatively, the filter device is designed such that the air outlet is higher than 1.8 m, in particular higher than 2 m, above the floor. In the majority of installation locations for secondary filter systems, the majority of the people present will have their ears more than one meter above the floor and less than 2 m or 1.80 m. This allows for structural optimization such that components with high noise emissions, such as fans or intake openings or air outlets, are designed on the floor or towards the floor, or are designed above a height of 1.80 m above the floor.Accordingly, noise exposure can also be measured from one meter to less than 2 meters above the floor. Placing filter devices with an outlet area in the zone above one meter above the floor allows the acoustic diffusion effect of the much larger filter surface compared to the smallest airflow cross-section (e.g., in a fan) to be utilized for noise reduction. The same applies to noise sources installed more than 1.8 meters above the floor. For example, a filter device with a housing that functions as a ceiling light and a filter function represents an ideal construction in terms of noise reduction.

[0029] According to another exemplary embodiment, the filter device comprises a control unit for controlling the fan unit, wherein the control unit is coupled to the fan unit for wireless or wired signal exchange of control commands. The control unit can be integrated into the filter device and control the fan unit. Furthermore, the control unit can form a central control unit, which is arranged outside the filter device and controls, for example, multiple filter devices.

[0030] According to a further exemplary embodiment, the filter device has a sensor element for determining at least one air parameter (e.g., CO content, CO2 content, relative humidity, air pressure, O2 content, temperature, PM content, aerosol concentration, type and / or concentration of foreign substances) of the air to be filtered at the filter device or an operating parameter of the filter device. The control unit is coupled for wireless (or wired) signal exchange of sensor signals from the sensor element. The sensor element can, for example, provide air quality-related and / or filter-related data to the control unit, in particular by means of RFID, NFC, Bluetooth, WLAN, or building management system protocols. The control unit is configured in particular such that, based on the filter-related data, a warning signal can be generated and / or a measure can be taken which affects a throughput through the filter device (e.g.,control of the fan unit) or functions of the filter device, which are locked or enabled.

[0031] The filter device and the control unit can each have an antenna or a conductor-based system that signals the readiness of the filter device to exchange data. Such data can not only relate to parameters relating to the airborne contaminants in the air, but can also contain information and details about the filter device. For example, the air volume through the filter device can be adjusted depending on the performance of a filter device used. Furthermore, if a running time or occupancy density of the filter medium is exceeded, a signal can be sent that can be interpreted either as a maintenance signal or used as a control signal to reduce or increase the air flow rate. One design variant of a transmitting device in the filter device and / or the control unit can be an RFID transponder (which, for example, also contains filter data in encrypted form).Furthermore, other communication mechanisms such as NFC, Bluetooth, WLAN, etc. can also be used. For wired communication, bus systems from building management systems (LON, EIB, etc.) are available in addition to proprietary protocols.

[0032] Since secondary filter systems are typically operated without a maintenance organization, high filter occupancy (due to a filter change that is due but not performed) is a further source of increased noise emissions (e.g., because the air flow monitor then operates the fan at higher power). For this reason, a filter occupancy monitor is integrated into the filter system, especially with a transmission option for the detected fault that extends beyond the local area of ​​the filter system (e.g., wired or wireless transmission of the fault message "Filter full / replace"). In particular, this allows an external service team to be requested and / or invited.

[0033] According to another exemplary embodiment, the sensor element is a dynamic pressure gauge and is particularly designed such that a static pressure upstream of the filter medium and a static and dynamic pressure downstream of the filter medium can be measured. If the air flow velocity is high enough, the differential pressure between a normal pressure tap upstream of the filter medium and a dynamic pressure tube (or Pitot tube) downstream of the filter medium can be measured. The pressure at the Pitot tube is given by the sum of the static pressure and the dynamic pressure and is therefore higher than at the normal pressure tap upstream of the filter medium. This configuration creates an inverted or negative differential pressure across the filter medium and allows for the detection of clogged supply lines or valve malfunctions. This embodiment can be particularly suitable for retrofitting older systems.By using the control unit in the filter device, it is possible to parameterize the response and / or limit values ​​in the filter device from the outside.

[0034] The sensor element can, for example, have a microphone and detect the noise level in the room and, in particular, the location of a noise source. By measuring and evaluating the noise level in a room, conclusions can be drawn about the number and intensity of people speaking in the room and the ventilation output of the fan unit can be adjusted accordingly via the control unit, since the emission of aerosols by people increases with the volume of speech. In other words, the ventilation output can be controlled based on the noise level in the room. The more people speak, or speak loudly, the more aerosols are emitted and the higher the fan output can be, since the additional noise from devices such as the fan unit is then not noticed and does not cause any disturbance.If one or more people are sitting quietly in the room, the ventilation performance drops because it needs to be quiet for concentrated work, but also because hardly any aerosols are emitted.

[0035] According to a further exemplary embodiment, the control unit obtains a unique ID from the filter device, wherein the unique ID contains information regarding the location of the filter device. The control unit receives the unique ID via NFC, Bluetooth, WLAN, proprietary protocols or protocols from building management systems, in particular LON or EIB, wherein the operation and / or configuration of the filter device can be adjusted based on the unique ID. In a further particularly preferred embodiment, the unique ID contains information regarding the installation location of the filter device in the filter system. This ID makes it possible to preselect the operating parameters required for the specific operation from a preconfigured operating mode of the filter device or to retrieve stored data of a system configuration.Particularly when using encrypted protocols, reconfiguration can be avoided when changing the filter, enabling a "plug and play" solution. Relevant data can be transferred from the filter device during the change or via the cloud. The unique ID can be transferred to the filter system using mechanisms familiar to those in the field, such as QR codes, barcodes, OCR fonts (and their successors for machine-readable fonts), RFID, NFC, Bluetooth, WLAN, proprietary protocols, or protocols from building management systems (LON, EIB, etc.). This mechanism also makes it possible to deliver a filter device in which functions are only activated if part of the unique ID is part of the agreed scope of delivery.

[0036] According to a further exemplary embodiment, the

[0037] The filter device further comprises a data storage unit which is coupled to the control unit, the fan unit and the sensor element for the exchange of data, wherein the data can be protected by means of a certificate and / or encryption. The data in particular represent measured values ​​which are selected from the group consisting of air flow through the filter device, air temperature, air pressure, in particular absolute pressure and / or differential pressure, filter occupancy of the filter medium, air humidity, aerosol load, PM content and / or foreign matter content of the air, and the measurement location of the air measurement. Especially under demanding operating conditions, it can be of interest that individual recording details, such as the measured values, can be parameterized. On the one hand, this concerns details of the measurement method, and on the other hand, the parameters which are to be recorded (e.g.Air flow, temperature, pressure (especially absolute pressure and / or differential pressure), filter occupancy, humidity, aerosol load, PM content, and especially how much of which diameter class. Such a data set can then be transmitted via communication or read out only after the end of the filter's service life.

[0038] According to a further exemplary embodiment, the sensor element is configured to determine an energy consumption and / or a CO2 footprint of the filter device based on the air parameter and / or the operating parameter of the filter device, in particular filter occupancy and / or operating time of the filter medium. The air parameters and / or operating parameters of the filter device are in particular selected to determine a recommendation regarding filter replacement and / or filter cleaning, in particular so that individual parameters are configurable. For example, a permanent and continuous optimization of energy consumption and CO2 footprint is carried out (possibly in real time). For example, it can be advantageous to replace a filter before the end of its life (e.g., maximum filter occupancy), since the filter occupancy over its lifetime results in an exponentially increasing pressure drop across the filter.Depending on energy costs or the requirements for the carbon footprint of the filter device, changing the filter before the steep increase in differential pressure occurs, while still within the filter's service life, can result in a cost or performance improvement. Another option could be to notify the user that additional ventilation by opening windows is an energy optimization measure, or, for example, if an improvement in air quality is detected, the secondary filter device can reduce air circulation, thus reducing energy and noise consumption.

[0039] According to a further exemplary embodiment, the control unit is configured to variably control the filter device, in particular the fan unit, in such a way that future energy availability and / or the current and / or future energy consumption of the filter device can be taken into account. The control unit controls the filter device automatically or semi-automatically with an approval function based on the future energy availability and / or the current and / or future energy consumption of the filter device and / or the building. In a further preferred embodiment, the control unit or the sensor element determines data on the energy consumption and / or the CO2 footprint of the filter device and / or the fan unit. As the filter medium becomes more and more occupied, it requires more and more energy for its intended use, since the pressure drop Delta P across the filter medium increases due to the filter occupation.Based on knowledge of the energy costs and the CO2 footprint of the filter medium due to its production, a recommendation regarding the optimal filter change time (or cleaning time) can be determined and communicated based on this data. Preferably, individual parameters such as energy costs, savings potential, CO2 savings, CO2 certificate costs, etc. are configurable or determinable. According to a further exemplary embodiment, the filter medium comprises a filter material containing a layer of nonwoven fabric, in particular several layers of nonwoven fabric, wherein the filter medium can be arranged interchangeably in the filter device. The filter medium is in particular a disposable filter. A nonwoven fabric consists of fibers of limited length, continuous fibers (filaments), or cut yarns that are assembled and bonded to form a nonwoven fabric (a fiber layer, a fiber pile).The interlinking of the fibers creates an air-permeable material with narrow, small-pore air passages, which achieves a good filtering effect, especially of air particles.

[0040] Since a replaceable filter medium (especially as a disposable filter) does not have to be precisely adapted to the surrounding housing of the filter device, it is also advantageous if the filter medium prevents possible air resonances. With filter materials made of regularly arranged filter media (e.g. woven, punched, etched or drilled filters), there is the possibility that self-organizing effects of the air flow may cause resonances and thus negative effects (noise, redetachment of already embedded pollutants, particularly when starting and stopping the system, in the event of variance in physical measured values, etc.). It has been shown that in the solution according to the invention, the use of a layer of nonwoven fabric dampens this vibration effect. This dampening occurs because fibers are irregularly and randomly laid down and adhered. This irregularity reduces the vibrational self-organization potential.This damping can be enhanced by using multiple nonwoven layers in the filter medium structure, especially if these layers comprise at least slightly different nonwoven materials or nonwoven layers. A difference can be created by the production of nonwoven materials. According to another exemplary embodiment, the filter medium comprises at least two nonwoven layers and a filter membrane arranged between the nonwoven layers, which are arranged one above the other in a layered composite. In particular, the middle filter membrane of the layered composite has a larger surface area than the two outer nonwoven layers.

[0041] According to another exemplary embodiment, a first direction (x-axis) and a second direction (y-axis) span an (xy) plane, wherein the central filter membrane is configured with corrugated sections such that the corrugated sections are arranged one behind the other along the first direction. The corrugated sections extend irregularly and asymmetrically to one another, particularly within the plane, wherein the filter medium is arranged such that air can flow over the filter medium along the first direction or along the second direction.

[0042] For example, the first direction is the direction of air flow. The wave sections run perpendicular to the first direction along the second direction. The asymmetry of the wave arrangement and shape can be used to dampen vibrations. Alternatively, the filter body can also be exposed to air flow in the Y direction, parallel to the extension of the waves. The wave sections thus form, for example, a sharkskin-like ribbed structure, which reduces flow resistance. Depending on the entry conditions (inlet cross-section, volume flow, depth of the filter material to be flowed through) into the filter medium, one or the other design can be particularly advantageous. The asymmetry of the wave arrangement can be achieved through a self-organizing compaction process in which the feed rate of the filter membrane is significantly higher than the feed rate of the two cover fleeces.The asymmetry of the wave arrangement is created by thermally fixing the three layers at a predetermined time. In addition to the advantages already described, this asymmetry has a stabilizing effect on deflections in the xy plane.

[0043] The filter membrane is stacked in a wave pattern and bonded (glued, welded, stapled, etc.) to a cover fleece at the top and bottom for stability. This ensures that sufficient open membrane areas are available throughout the service life of the filter medium, preventing them from flattening or folding over when loaded, thus further reducing the permeability.

[0044] If the filter medium also incorporates a non-flat filter membrane, the above effects are further enhanced. If the filter medium has no sharp edges (as with pleated cartridge filters, for example), this has a noise-reducing effect. A good way to achieve this "non-angularity" is to create a sinusoidal impact zone.

[0045] The corrugated filter construction with its ribbed structure creates greater resistance for the passing air. If the filter medium is positioned lengthwise or diagonally to the airflow, a low-velocity airflow is created that surrounds the main airflow (or accompanies it laterally if only a partial filter medium is applied). This reduced velocity dampens the sound of the airflow. As the air flows past the corrugated filter construction, a defined amount of the airflow flows through the corrugated filter medium, similar to a duct silencer or absorption silencer, thereby reducing the mass flow of the main airflow and, as explained above, the flow velocity of the main airflow, thus dampening the sound of the airflow.According to a further exemplary embodiment, the filter medium has a thickness of 2 mm to 10 mm, in particular of 3 mm to 7 mm, and / or the number of wave sections is between 0.5 and 3 waves per cm.

[0046] This allows a filtering performance similar to a HEPA filter, but with a pressure drop in the range of a normal F7 filter (i.e. within the operating parameters of the inventive solution).

[0047] According to another exemplary embodiment, a surface area of ​​the filter membrane is more than 30% larger, in particular more than 80% larger, and furthermore in particular more than 200% larger than the respective surface area of ​​the outer nonwoven layers. In particular, good noise emission reductions have been achieved when the surface area of ​​the filter membrane is more than 30% larger, in particular more than 80% larger, and preferably more than 200% larger than the filter area, in particular the filter surface of the outer nonwoven layers. This is explained by the diffusion effect of the filter membrane when it is not a flat element (with possible acoustic reflection effect).

[0048] According to a further exemplary embodiment, the filter device has a weighing device configured to weigh the filter occupancy, in particular such that any measurement value distortion caused by the pressure of the air flowing through the system can be compensated. With appropriate additional mechanisms, compensation for the measurement value distortion of the sensor element caused by the pressure of the air resistance during operation of the filter device can be achieved. This also allows the detection of a high filter occupancy of the filter medium for a filter device operating mode with a low (low) volume flow, which in conventional filter monitoring systems does not trigger the differential pressure monitoring of the filter medium. Particularly in secondary filter devices, efforts are made to operate with low, low pressure differences so that the noise level remains low. This detail allows reliable measurement of the filter occupancy despite very low pressure differences.In particular, the weighing device can have contact with the ground when the filter medium is installed in the housing of the filter device, thus transferring the weight of the filter medium to the ground. This allows a weight measurement of the filter medium to be performed.

[0049] According to a further exemplary embodiment, the filter medium comprises a filter material which is hydrophobic and / or contains a natural fiber or a polyolefin, in particular a polypropylene, in particular the filter contains cellulose, cotton and / or hemp. If the air flow to be filtered is loaded with a high aerosol load, known filters can tend to suddenly become moist. On the one hand, this can statically increase the pressure drop across the filter, but also dynamically, due to the very rapidly changing pressure conditions, can overwhelm a subsequent volume flow control by means of VAV in terms of its control speed. The solution according to the invention can solve this problem by a suitable choice of material for the filter material. Either a hydrophobic material (e.g.a polyolefin, in particular polypropylene, which is essentially free of polar groups) and / or an absorbent material with a special (e.g. deep, low) swelling tendency (e.g. a natural fiber, in particular a cellulose fiber, cotton or hemp) is used. This reduces the tendency for filter openings to become clogged with micro- or nanoscale water droplets. The fungicidal, virucidal and bactericidal properties of hemp have been shown to be beneficial and make it an ideal filter component. This reduction in pressure drop also leads to fewer spatially unstable measurements (i.e., with a smaller pressure drop, more air is sucked through and therefore a larger spatial image is relevant for the measured values ​​than is expected when assessed as a composite.) According to a further exemplary embodiment, the filter medium comprises a vibroacoustic metamaterial.Vibroacoustic metamaterials consist of a periodic arrangement of small resonator structures distributed in an array, each composed of several materials. The size of the resonators can be smaller than half the wavelength of the vibration to be reduced. Vibroacoustic metamaterials are cost-effective to manufacture. The vibroacoustic metamaterials can line part of the air duct, thus dampening the sound. Additionally, they can be tuned to the most disruptive natural resonant frequency of the secondary filter device and, depending on the design, reduce sound emissions by a further 1.5 to 10 dB.

[0050] According to a further exemplary embodiment, the filter device has a housing in which the filter medium and the fan unit are arranged. The housing can be arranged in a room of a building and can be designed, for example, as a room divider. Furthermore, the housing can have a lamp and be configured as a luminaire. Furthermore, the housing can have a loudspeaker. Furthermore, the housing can have a sound-absorbing layer and can be configured as a sound damper and / or as a sound absorber. Thus, in a further particularly preferred embodiment, the secondary filter device can be connected to at least one further room-relevant additional function. This can be an interior design element, a room divider, a luminaire, a loudspeaker, or a sound damper. This combination achieves material savings (for example, for the housing) compared to the respective independent stand-alone devices.

[0051] When it comes to noise reduction, it is essential that the design of the filter device specifically distinguishes between laminar and turbulent flow and that the corresponding noise emissions are specifically minimized. It was recognized that, through the inventive measures described above, a replaceable filter (especially a disposable filter) does not have to be precisely adapted to the surrounding container and can still prevent possible air resonances. In filter devices made of regularly arranged filter media (e.g., woven, punched, etched, or drilled filters), there is a possibility that resonances and thus negative effects (noise, re-detachment of already embedded pollutants [especially during start-up and stop-up of the system], variance in physical measured values, etc.) may arise due to self-organizing effects of the air flow.It has been shown that, with a solution according to the invention, even the use of just one layer of nonwoven fabric dampens this vibration effect. Naturally, this dampening is increased with multiple nonwoven layers in the filter medium's structure, especially if they are at least slightly different. This is explained by the manufacturing process of nonwoven materials. Typically, fibers are laid down irregularly / randomly and bonded together. This irregularity reduces the potential for vibrational self-organization, which can lead to increased noise.

[0052] The particularly large filter surfaces, for acoustic reasons, are also ideal as sound absorbers. In particular, when combined with special sound-absorbing materials (e.g., melamine resins), a particularly good level of sound insulation (both for external noise and noise from the filter system itself) can be achieved while still maintaining sufficient airflow.

[0053] It should be noted that the embodiments described here represent only a limited selection of possible embodiments of the invention. It is thus possible to combine the features of individual embodiments in a suitable manner, so that a multitude of different embodiments can be regarded as obviously disclosed to a person skilled in the art with the embodiments explicitly described here. In particular, some embodiments of the invention are described with device claims and other embodiments of the invention with method claims. However, upon reading this application, it will immediately become clear to a person skilled in the art that, unless explicitly stated otherwise, in addition to a combination of features belonging to one type of subject matter of the invention, any combination of features belonging to different types of subject matter of the invention is also possible.

[0054] Short description of the drawings

[0055] For further explanation and better understanding of the present invention, embodiments are described in more detail below with reference to the accompanying drawings.

[0056] Fig. 1 shows a schematic representation of a filter device according to an exemplary embodiment of the present invention.

[0057] Fig. 2 shows a schematic representation of a room with exemplary embodiments of the filter device according to the invention.

[0058] Fig. 3 shows a schematic representation of a filter medium with a wave-shaped filter membrane according to an exemplary embodiment.

[0059] Fig. 4 shows a schematic representation of a filter medium with a wave-shaped filter membrane and corrugated cover layers according to an exemplary embodiment. Fig. 5 shows a schematic representation of waveforms of the filter medium according to an exemplary embodiment.

[0060] Fig. 6 shows a schematic representation of a filter medium with a dynamic pressure gauge according to an exemplary embodiment.

[0061] Fig. 7 shows a diagram of a pressure drop of air flowing through the filter over the operating time of the filter medium.

[0062] Fig. 8 shows a schematic representation of an active noise reduction according to an exemplary embodiment.

[0063] Detailed description of exemplary implementation forms

[0064] Identical or similar components in different figures are provided with the same reference numerals. The representations in the figures are schematic.

[0065] Fig. 1 shows a filter device 100 for filtering air 103 in a room 200 (see Fig. 2) of a building. The filter device 100 has a filter medium 101 and a fan unit 102, wherein air 103 to be filtered can flow through the filter medium 101 for filtering by means of the fan unit 102. A filter surface of the filter medium 101 is five times larger than a smallest air flow cross-section in the fan unit 102, such that an air flow angle 104 between the flow direction of the air 103 at the filter entry into the filter medium 101 and a filter surface of the filter medium 101 differs from 90 degrees and the sound pressure level of the filter device 100 at a distance of one meter from the filter device 100 at a volume flow of over 50 m 3 / h of the air 103 driven by the fan unit 102 is below 48 dB, wherein the filter medium 101 is configured such that the pressure drop of the air 103 flowing through the filter medium 101 is less than 450 Pascal.

[0066] The filter device 100 comprises, for example, a housing 120 in which a filter medium 101 is arranged, or a plurality of filter media 101 are arranged in series along the flow direction of the air 103 through the filter device 100 or parallel to the flow direction. The filter medium 101 can be provided in an interchangeable manner.

[0067] The filter medium 101 of the filter device 100 comprises, for example, a flat filter material that is fixed in a circumferential support frame. The filter medium 101 can be designed as a pocket filter, wherein a plurality of pockets of filter medium 101 are fastened in the support frame, and the air flow is introduced into the pockets to filter the incoming air 103.

[0068] The fan unit 102 of the filter device 100 draws, in particular, air 103 to be filtered into the filter device 100, so that the air 103 flows through the filter medium 101. The fan unit 102 can, for example, have an axial or radial compressor, and accordingly, the air 103 can flow along a translational flow in a straight line or at right angles. The fan unit 102 can, in particular, be controlled by the control unit 108, so that the air flow through the filter device 100 is adjustable. The fan unit 102 is, in particular, a secondary air circulation system with filtration for installation in a room 200 (a "room air purifier," so to speak). The filter device 100 can be mobile or stationary.

[0069] According to the invention, the filter area AF of the filter medium 101 is five times larger than a smallest air flow cross section AL in the fan unit 102. The smallest air flow cross section AL describes the smallest flow cross section in the air path of the air 103 through the filter device 100, ie between the inlet of the air 103 into the flow channel 111 of the fan unit 102 and the outlet of the air 103 from the flow channel 112 of the filter medium 101. The smallest flow cross section AI can be present, for example, in an air channel of the filter device 100 in which a flow-generating element (e.g. a fan) of the fan unit 102 is arranged.

[0070] The filter medium 101 is arranged downstream of the smallest airflow cross-section AL. Between the smallest airflow cross-section AL and the filter medium 101, the airflow cross-section of the air path through the filter device 100 expands, so that the air 103 strikes a filter medium 101, which has a filter area AF that is five times larger than the smallest airflow cross-section AL in the fan unit 102.

[0071] Between the filter medium 101 and the smallest airflow cross-section AL, there is only an expansion of the airflow path, so that the linear portion of the airflow against the filter medium 101 flow direction at filter inlet differs from 90 degrees to a filter surface of the filter medium 101 and has an airflow angle 104 between the flow direction and the filter surface of other than 90 degrees. In particular, the filter surface is parallel to the smallest airflow cross-section AL or parallel to an airflow cross-section AL before the expansion of the airflow path begins.

[0072] The expansion area also forms a long expansion zone without, for example, hard transitions after the fan unit 102. Particularly good results have been found when the expansion zone is larger or longer than the cross-section AL of the air flow, in particular more than twice or even four times the cross-section of the air flow. If the air duct is constructed in such a way that the main flow direction of the air 103 at the filter surface at the inlet of the filter medium 101 is not directed in a straight line through the filter medium 101, but rather is mostly deflected first, for example by more than 10 degrees, a rotational movement is initiated, especially for larger particle or aerosol fractions of the air 103, which achieves a better separation rate on a filter (particularly in combination with a multi-layer pore filter together with a cyclone separation effect). The cyclone separation effect allows for more stable binding of the foreign substances.The inertial movement of heavier air flow components achieved by the air deflection leads to better adhesion to the filter material in the filter medium 101 and thus a better separation rate.

[0073] By means of this widening of the flow cross-section, it is achieved that the sound pressure level of the filter device 100 at a distance of one meter from the filter device 100 (in particular from the air outlet and / or the air inlet of the filter device 100) at a volume flow of more than 50 m 3 / h of the air 103 driven by the fan unit 102 is below 48 dB.

[0074] Since the filter area AF is significantly larger than the inflow cross-section or the airflow cross-section AL in the fan unit 102 of the air to be cleaned 103, this also results in a change in the velocity of the airflow. Highly accelerated heavy solid particles (or aerosols) reduce their velocity more slowly than the light air molecules. This means that they impact the filter medium 101 relatively strongly, which in turn leads to good adhesion to the filter (and thus to particularly good depletion).

[0075] The filter device 100 has a control unit 108 for controlling the fan unit 102, wherein the control unit 108 is coupled to the fan unit 102 for wireless or wired signal exchange of control commands. The control unit 108 can be integrated into the filter device 100 and control the fan unit 102.

[0076] The filter device 100 further comprises a sensor element 109 for determining at least one air parameter (e.g., CO content, CO2 content, relative humidity, air pressure, O2 content, temperature, PM content, aerosol concentration, type and / or concentration of foreign substances) of the air 103 to be filtered at the filter device 100 or an operating parameter of the filter device 100. The control unit 108 is coupled for wireless (or wired) signal exchange of sensor signals from the sensor element 109. The control unit 108 is configured, in particular, such that, based on the filter-related data, a warning signal can be generated and / or a measure can be taken which relates to a throughput through the filter device 100 (e.g., control of the fan unit) or relates to functions of the filter device 100 which are blocked or enabled.

[0077] The filter device 100 and the control unit 108 may each have an antenna or a conductor-based system that signals the readiness of the filter device 100 to exchange data.

[0078] The filter device 100 further comprises a data storage unit 110, which is coupled to the control unit 108, to the fan unit 102, and to the sensor element 109 for the exchange of data, wherein, in particular, the data can be protected by means of a certificate and / or encryption. The data represent, in particular, measured values ​​selected from the group consisting of air flow through the filter device 100, air temperature, air pressure, in particular absolute pressure and / or differential pressure, filter occupancy of the filter medium, air humidity, aerosol load, PM content and / or foreign matter content of the air 103, and the measurement location of the air measurement. Especially under demanding operating conditions, it may be of interest that individual recording details, such as the measured values, can be parameterized. On the one hand, this concerns details of the measurement method, and on the other hand, the parameters to be recorded (e.g.Air flow, temperature, pressure (especially absolute pressure and / or differential pressure), filter occupancy, humidity, aerosol load, PM content, and especially how much of which diameter class. Such a data set can then be transmitted via communication or read out only after the end of the filter's service life.

[0079] The filter device 100 further comprises a weighing device 113 configured to weigh the filter occupancy, in particular, such that a measurement value distortion caused by the pressure of the air 103 flowing through the system can be compensated. With appropriate additional mechanisms, a compensation for the measurement value distortion of the sensor element 109 caused by the pressure of the air resistance during operation of the filter device 100 can be achieved. This also allows the detection of a high filter occupancy of the filter medium 101 for an operating mode of the filter device 100 with a low (low) volume flow, which does not trigger the differential pressure monitoring of the filter medium 101 in conventional filter monitoring systems.

[0080] Fig. 2 shows a schematic representation of a room 200 with exemplary embodiments of the filter device 100 according to the invention. The filter device 100, e.g. its housing 120, has an air outlet 107 for blowing out the air 103, wherein the filter device 100 is designed such that the air outlet 107 is lower than 1 m, in particular lower than 0.5 m, above the floor (on which the filter device 100 rests) and thus below a head height 201 of a standing person. Additionally or alternatively, the filter device 100 is designed such that the air outlet 107 is higher than 1.8 m, in particular higher than 2 m, than a head height 201 of a standing person. The housing 120 can be arranged in a room 200 of a building and is designed, for example, as a room divider. Furthermore, as shown, the housing 120 may include a lamp 202 and be configured as a light.In addition, the filter device 100 can also be attached to a wall of a room 200.

[0081] Fig. 3 shows a schematic representation of a filter medium 101 with a wave-shaped filter membrane according to an exemplary embodiment. The filter medium 101 has, in particular, a plurality of filter layers (e.g., nonwoven layers) 301, 302, 303, which are arranged one behind the other in the flow direction of the air 101 through the filter medium 101. In particular, the first filter layer 301 facing the supply air side filters more coarsely than at least one of the second filter layers 302, 303 following the first filter layer in the flow direction. Thus, coarser particles can be filtered first, while smaller particles flow through the first layers and are only later filtered out in the finer layers.

[0082] The outer filter layers are arranged as nonwoven layers 301, 303, and one filter layer is arranged as a filter membrane 302 between the nonwoven layers 301, 303. The nonwoven layers 301, 302, 303 are arranged in layers one above the other in a layered composite in a third direction z, wherein, in particular, the middle filter membrane 302 of the layered composite has a larger surface area than the two outer nonwoven layers 301, 303. The middle filter membrane 302 has corrugated sections arranged one behind the other along a first direction x.

[0083] Fig. 4 shows a schematic representation of a filter medium 101 with a wave-shaped filter membrane 302 and corrugated cover layers as nonwoven layers 301, 303 according to an exemplary embodiment. On the supply air side, a coarse cover fleece is provided as the outer nonwoven layer 301, which is arranged in a corrugated manner on the supply air side of the filter membrane 302. Likewise, a cover fleece can be arranged as the nonwoven layer 303 on the exhaust air side of the filter membrane 502. The outer nonwoven layer 301 on the supply air side is more corrugated than the outer nonwoven layer 303 on the exhaust air side. The filter membrane 302 is strongly corrugated and accordingly also has a strong filtering effect. The intermediate area between the outer nonwoven layers 301, 303 and the corrugations of the filter membrane 302 can be filled with a film material to achieve greater stability.

[0084] Fig. 5 shows a schematic representation of waveforms of the filter medium 101 according to an exemplary embodiment. The wave sections run irregularly and asymmetrically to one another, particularly within the plane. The filter medium 101 is arranged such that air 101 can flow over the filter medium 101 along the first direction x or along the second direction y. For example, the x direction is the air flow direction of the air 101, and the wave sections run transversely to the first direction x along the second direction y. The asymmetry of the wave arrangement and shape can be used for vibration damping.

[0085] Fig. 6 shows a schematic representation of a filter medium 101 with a dynamic pressure gauge 602 according to an exemplary embodiment.

[0086] The dynamic pressure gauge 602 is designed to measure a static pressure upstream of the filter medium 101 and a static and dynamic pressure downstream on the exhaust air side after the filter medium 101. If the air flow velocity is high enough, the differential pressure p1-p2 can be measured between a normal pressure tap upstream of the filter medium 101 (pressure p1) and a dynamic pressure tube (or Pitot tube) downstream of the filter medium 101 (pressure p2). The filter medium 101 is arranged within an air duct formed by walls as an external airflow boundary 601. The pressure at the Pitot tube is given by the sum of the static pressure and the dynamic pressure and is therefore higher than at the normal pressure tap upstream of the filter medium 101.This configuration creates an inverted or negative differential pressure across the filter media 101 and allows for the detection of clogged supply lines or valve malfunctions.

[0087] Fig. 7 shows a diagram of a pressure drop of air 103 flowing through the filter over the operating time of the filter medium 101. The diagram shows that over the operating time t, due to the filter occupancy, the pressure drop AP of the air 103 flowing through the filter medium 101 increases. The filter medium 101 is configured such (for example, via the material / pore density, the material selection and / or the thickness of the filter medium 101) that the pressure drop (between entry into the filter medium 101 and exit from the filter medium 101) of the air 103 flowing through the filter medium 101 is less than 450 Pascal in a regular, predefined operating cycle defined by a predetermined operating time.

[0088] Fig. 8 shows a schematic representation of active noise reduction according to an exemplary embodiment. The filter device 100 has a microphone unit 105 and a sound generator 106, wherein the microphone unit 105 is arranged to measure the sound level 804 of the air 103 as the noise source 803 upstream of the fan unit 102 and / or downstream of the filter medium 101, wherein the sound generator 106 is configured to generate counter-sound based on the measured sound level 804. Thus, active noise suppression can be integrated. The sound generator 106 generates sound which is adjusted such that it can be set with destructive interference with the noise source 803 generated by the air flow. For this purpose, a controller 101 (for example, the control unit 108) is coupled to the microphone unit 105 to generate signals for the sound generator 106. These signals can be amplified in an 802 power amplifier.

[0089] Additionally, it should be noted that "comprising" does not exclude other elements or steps, and "a" or "an" does not exclude a plurality. Furthermore, it should be noted that features or steps described with reference to one of the above embodiments may also be used in

[0090] Combination with other features or steps of other embodiments described above. Reference numerals in the claims are not to be considered as limiting.

[0091] Reference list:

[0092] 100 Filter device 801 Regulator

[0093] 101 Filter medium 802 Power amplifier

[0094] 102 Fan unit 803 Noise source

[0095] 804 sound level

[0096] 103 Air

[0097] 104 Airflow angle x first direction

[0098] 105 Microphone unit y second direction

[0099] 106 Sound generator z third direction

[0100] 107 Air outlet pl pressure supply air side

[0101] 108 Control unit p2 pressure exhaust air side

[0102] 109 Sensor element

[0103] AL airflow cross-section fan unit

[0104] 110 Data storage unit

[0105] AF filter area filter medium

[0106] 111 Flow duct fan unit

[0107] 112 Flow channel filter medium

[0108] 113 Weighing device

[0109] 120 housings

[0110] 200 room

[0111] 201 Head height of a standing person

[0112] 202 Lamp

[0113] 301 first fleece layer

[0114] 302 filter membrane

[0115] 303 second fleece layer

[0116] 601 outer airflow limitation

[0117] 602 Pitot pressure gauge

Claims

1. Filter device (100) for filtering air (103) in a room (200) of a building, the filter device (100) comprising a filter medium (101), a fan unit (102), wherein air (103) to be filtered can flow through the filter medium (101) for filtering by means of the fan unit (102), wherein a filter surface of the filter medium (101) is five times larger than a smallest air flow cross-section in the fan unit (102), such that an air flow angle (104) between the flow direction of the air (103) at the filter entry into the filter medium (101) and a filter surface of the filter medium (101) differs from 90 degrees and the sound pressure level of the filter device (100) at a distance of one meter from the filter device (100) at a volume flow of more than 50 m 3 / h of the air (103) driven by the fan unit (102) is below 48 dB, wherein the filter medium (101) is configured such that the pressure drop of the air (103) flowing through the filter medium (101) is less than 450 Pascal.

2. Filter device (100) according to claim 1, wherein the filter surface of the filter medium (101) is designed to be larger than a smallest air flow cross-section in the fan unit (102) such that at a distance of one meter the sound pressure level of the filter device (100) is below 45 dB, in particular below 38 dB, in particular below 32 dB, further in particular below 28 dB.

3. Filter device (100) according to claim 1 or 2, wherein the filter medium (101) is designed such that a pressure drop of the air flowing through (103) through the filter medium (101) is below 250 Pa, in particular below 150 Pa, further in particular below 70 Pa or 30 Pa.

4. Filter device (100) according to one of claims 1 to 3, wherein the filter surface of the filter medium (101) is 10 times larger, in particular more than 20 times larger, further in particular more than 40 times larger than a smallest air flow cross-section in the fan unit (102) and / or wherein the filter medium (101) is provided with a filter surface (AF) larger than 1 m 2 , especially larger than 2 m 2 , especially larger than 4 m 2 , especially larger than 8 m 2 is trained.

5. Filter device (100) according to one of claims 1 to 4, wherein the filter device (100) is configured such that an air volume per hour and square meter of filter area is less than 600 m 3 / (m 2 xh), especially below 140 m 3 / (m 2 xh), under 85 m 3 / (m 2 xh) or less than 50 m 3 / (m 2xh), and / or the speed of the volume flow of the air (103) through the filter device (100) is in the range 0.1 to 5 m / s, in particular in the range 0.2 m / s to 3.4 m / s, further in particular between 0.3 m / s to 2.8 m / s.

6. Filter device (100) according to one of claims 1 to 5, further comprising a microphone unit (105), and a sound generator (106), wherein the microphone unit (105) is arranged to measure the sound level of the air (103) before the fan unit (102) and / or after the filter medium (101), wherein the sound generator (106) is configured to generate a counter sound based on the measured sound level.

7. Filter device (100) according to one of claims 1 to 6, further comprising an air outlet (107) for blowing out the air (103), wherein the filter device (100) is designed such that the air outlet (107) is located lower than 1 m, in particular lower than 0.5 m, above the ground, and / or wherein the filter device (100) is designed such that the air outlet (107) is located higher than 1.8 m, in particular higher than 2 m, above the ground.

8. Filter device (100) according to one of claims 1 to 7, further comprising a control unit (108) for controlling the fan unit (102), wherein the control unit (108) is coupled to the fan unit (102) for wireless signal exchange of control commands.

9. Filter device (100) according to claim 8, further comprising a sensor element (109) for determining at least one Air parameters of the air to be filtered (103) at the filter device (100) or an operating parameter of the filter device (100), wherein the control unit (108) is coupled in particular for the wireless signal exchange of sensor signals of the sensor element (109), wherein the sensor element (109) provides in particular air quality-related and / or filter-related data to the control unit (108), in particular by means of RFID, NFC, Bluetooth, WLAN or building management system protocols, wherein the control unit (108) is configured in particular such that, on the basis of the filter-related data, a warning signal can be generated and / or a measure can be taken which relates to a throughput through the filter device (100) or relates to functions of the filter device (100) which are blocked or enabled.

10. Filter device (100) according to claim 9, wherein the sensor element (109) is a dynamic pressure gauge and is designed in particular such that a static pressure upstream of the Filter medium (101) and a static and dynamic pressure downstream of the filter medium (101) can be measured, and / or wherein the sensor element (109) has a microphone which is configured to detect the noise level in a room (200) in such a way that the number and intensity of people speaking in the room can be determined by measuring and evaluating the noise level in the room (200).

11. Filter device (100) according to one of claims 8 to 10, wherein the control unit (108) obtains a Unique ID from the filter device (100), wherein the Unique ID comprises information regarding the location of the filter device (100), wherein the control unit (108) receives the Unique ID via NFC, Bluetooth, WI_AN, proprietary protocols or protocols of building management systems, in particular LON or EIB, wherein the operation and / or the configuration of the filter device (100) can be adjusted based on the Unique ID.

12. Filter device (100) according to claim 9 or 11, further comprising a data storage unit (110) which is coupled to the control unit (108), to the fan unit (102) and to the sensor element (109) for exchanging data, wherein in particular the data can be protected by means of a certificate and / or encryption, wherein in particular the data represent measured values ​​selected from the group consisting of air flow through the filter device (100), air temperature, air pressure, in particular absolute pressure and / or differential pressure, filter occupancy of the filter medium (101), air humidity, aerosol load, PM content and / or foreign matter content of the air (103), measuring location of the air measurement.

13. Filter device (100) according to one of claims 9 to 12, wherein the sensor element (109) is configured to determine an energy consumption and / or a CO2 footprint of the filter device (100) based on the air parameter and / or the operating parameter of the filter device (100), in particular filter occupancy and / or operating time of the filter medium (101), wherein the air parameters and / or operating parameters of the filter device (100) are in particular selected to determine a recommendation regarding filter replacement and / or filter cleaning, in particular that individual parameters are configurable.

14. Filter device (100) according to one of claims 8 to 13, wherein the control unit (108) is configured to variably control the filter device (100), in particular the fan unit (102), in such a way that a future energy availability and / or the current and / or future energy consumption of the filter device (100) can be taken into account, wherein the control unit (108) automatically or semi-automatically with an approval function controls the filter device (100) based on the future energy availability and / or the current and / or future energy consumption of the filter device (100) and / or the building.

15. Filter device (100) according to one of claims 1 to 14, wherein the filter medium (101) comprises a filter material which contains a layer of nonwoven fabric, in particular a plurality of layers of nonwoven fabric (301, 303), wherein the filter medium (101) can be arranged exchangeably in the filter device (100), wherein in particular the filter medium (101) is a disposable filter.

16. Filter device (100) according to claim 15, wherein the filter medium (101) comprises at least two nonwoven layers (301, 303) and a filter membrane (302) arranged between the nonwoven layers (301, 303). which are arranged in layers one above the other in a layered composite, wherein in particular the middle filter membrane (302) of the layered composite has a larger surface than the two outer nonwoven layers (301, 303).

17. Filter device (100) according to claim 16, wherein a first direction (x) and a second direction (y) span a plane, wherein the middle filter membrane (302) is corrugated with wave sections such that the wave sections are arranged one behind the other along a first direction (x), wherein the wave sections run irregularly and asymmetrically to one another, in particular within the plane, and wherein the filter medium (101) is arranged such that the filter medium (101) can be flowed over with air (103) along the first direction (x) or along the second direction (y).

18. Filter device (100) according to claim 17, wherein the filter medium (101) has a thickness of 2 mm to 10 mm, in particular of 3 mm to 7 mm, and / or wherein the number of wave sections is between 0.5 and 3 waves per cm.

19. Filter device (100) according to one of claims 15 to 18, wherein a surface of the filter membrane (302) is more than 30% larger, in particular more than 80% larger, further in particular more than 200% larger than the respective surface of the outer nonwoven layers (301, 303).

20. Filter device (100) according to one of claims 1 to 19, further comprising a weighing device (113) which is designed to weigh the filter occupancy, in particular such that a measurement value falsification by the pressure of the air flowing through the system (103) can be compensated.

21. Filter device (100) according to one of claims 1 to 20, wherein the filter medium (101) comprises a filter material which is hydrophobic and / or contains a natural fiber or a polyolefin, in particular a polypropylene, in particular that the filter contains cellulose, cotton and / or hemp.

22. Filter device (100) according to one of claims 1 to 21, wherein the filter medium (101) comprises a vibroacoustic metamaterial.

23. Filter device (100) according to one of claims 1 to 22, further comprising a housing (120) in which the filter medium (101) and the fan unit (102) are arranged, wherein the housing (120) can be arranged in a room (200) of a building and is designed as a room divider, or the housing (120) has a light and is configured as a light, or wherein the housing (120) has a loudspeaker, or wherein the housing (120) has a sound-absorbing layer and is configurable as a sound damper and / or as a sound absorber.

24. A method for filtering air (103) in a room (200) of a building with a filter device (100) according to one of claims 1 to 23.

Images