AIR FILTER UNIT, IN PARTICULAR HEAVY Particulate Filter UNIT AND METHOD FOR ITS MANUFACTURING

Description

[0001] The present invention relates to an air filter unit, in particular a HEPA filter unit, comprising a filter body for separating substances from the air and a filter frame enclosing the filter body, as well as an air filter system comprising a ventilation pipe and the aforementioned air filter unit. The present invention further relates to a method for manufacturing the aforementioned air filter unit and to the use of a layer arrangement for a filter frame of an air filter unit, in particular a HEPA filter unit. State of the art

[0002] HEPA filters are commonly found with a filter body enclosed within a filter frame. Depending on the requirements, the filter body is designed to be antimicrobial. The filter frame is typically made of MDF, a metal (e.g., aluminum), or a plastic (e.g., polypropylene). HEPA filters with such frames are relatively heavy. Furthermore, MDF frames are susceptible to swelling upon contact with emulsions, while aluminum frames are expensive and more complex to manufacture.

[0003] Also known are fittings made of a "sandwich construction" with a rigid polyurethane foam core and aluminum lamination on both sides, which have an antimicrobial coating on the outer surfaces. Such fittings are used for the manufacture of ventilation ducts.

[0004] DE 10 2012 007 625 A1 discloses a filter device with a filter body and a filter frame enclosing the filter body, wherein the edge region of the filter body is connected to the filter frame via a cured bonding medium.

[0005] DE 10 2020 007 515 A1 discloses an air purifier platform with high-performance antiviral and antibacterial filters.

[0006] US 2017 / 0368488 A1 and US 2022 / 0065494 A1 reveal a filter with a filter frame.

[0007] The object of the present invention is therefore to provide an air filter which is easy to manufacture and has a low weight with good resistance. Description of the invention

[0008] Against this background, the approach presented here introduces an air filter unit, in particular a HEPA filter unit, with a filter body for separating substances from the air and a filter frame enclosing the filter body, wherein the filter frame has a layer arrangement comprising a rigid foam layer and at least one flexible outer layer on an outer side of the filter frame, wherein the outer layer comprises or is made of aluminium.

[0009] Furthermore, an air filtration system with a ventilation pipe and an air filter unit of the aforementioned type is presented, which is arranged in the ventilation pipe for the separation of substances from the flowing air.

[0010] Furthermore, a method for manufacturing an air filter unit, in particular of the aforementioned type, is presented, comprising the following steps: Providing a layer arrangement, in particular a plate-shaped one, comprising a rigid foam layer and at least one flexible outer layer, which has or consists of aluminium, on an outer surface of the layer arrangement; cutting at least two, in particular three, V-shaped grooves into the layer arrangement to obtain at least three, in particular four, layer sections which are / remain connected to each other by means of the flexible outer layer; cutting chamfers at two opposite layer ends of the layer arrangement; applying an adhesive to an inner surface of the layer arrangement; and arranging a filter body for separating substances from the air onto one of the layer sections and connecting the two opposite layer ends by folding the layer arrangement at the V-shaped grooves to form a filter frame that encloses the filter body and thus obtains the air filter unit;or joining the two opposite layer ends by folding the layer arrangement at the V-shaped grooves to form a filter frame, and arranging a filter body for separating substances from the air in the filter frame such that the filter frame encloses the filter body to obtain the air filter unit.

[0011] Finally, the present invention relates to the use of a layer arrangement comprising a rigid foam layer and at least one flexible outer layer, which has or consists of aluminium, on an outer side of the layer arrangement for a filter frame of an air filter unit, in particular a HEPA filter unit.

[0012] The present invention provides an air filter unit which, due to the layer arrangement according to the invention, is lightweight, durable, robust, and easy to manufacture. This is achieved, firstly, by the fact that the layer arrangement includes a rigid foam layer that is easy to work with and process, allowing for the realization of a filter frame with both sufficient stability and reduced weight. The flexible outer layer, in turn, provides mechanical protection for the filter frame and prevents the ingress of fluids. Furthermore, the flexible outer layer facilitates easy cleaning of the filter frame.

[0013] The air filter unit is preferably designed or configured for use or installation in air filter systems and air purification systems.

[0014] The air filter unit is preferably designed as a HEPA filter unit, e.g., an EPA, HEPA, or ULPA HEPA filter unit. For this purpose, the air filter unit has a filter body for separating substances, especially particulate matter, from the air. The filter body can, for example, comprise or consist of a filter fabric and / or a filter fleece and / or a filter mat. The filter body can have an antimicrobial coating.

[0015] The air filter unit further comprises a filter frame in which the filter body is enclosed. The filter frame is preferably rectangular, and in particular square. However, the filter frame can have any suitable or technically advantageous shape without departing from the scope of the present invention.

[0016] According to the invention, the filter frame has a layered arrangement comprising a rigid foam layer and at least one flexible outer layer on an outer surface of the filter frame or the layered arrangement. In other words, the frame wall of the filter frame, particularly its circumference, has a layered arrangement comprising a rigid foam layer and at least one flexible outer layer on an outer surface of the filter frame. Therefore, the layered arrangement constitutes the frame wall of the filter frame.

[0017] The layer arrangement is designed to be pressure-resistant. The layer arrangement can have a thickness of 5 mm or greater than or equal to 50 mm or less.

[0018] The rigid foam layer is designed to be pressure-resistant. The rigid foam layer preferably comprises a plastic, in particular polyurethane, or preferably consists of a plastic, in particular polyurethane. However, the rigid foam layer can also comprise or consist of polystyrene or polyvinyl chloride, or any suitable plastic known to those skilled in the art. Polyurethane, as well as polystyrene or polyvinyl chloride, are very well suited because the respective rigid foam layers are advantageously lightweight, pressure-resistant, thermally insulating, and sound-insulating.

[0019] The outer layer is preferably arranged on the rigid foam layer. Furthermore, the outer layer is preferably arranged directly on the rigid foam layer.

[0020] Preferably, the outer layer is designed as a lamination. In other words, the outer layer is bonded to the rigid foam layer by means of lamination.

[0021] Preferably, the outer layer is designed to be waterproof.

[0022] Preferably, the outer layer has an antimicrobial and / or antibacterial and / or antiviral coating, in particular a silver ion coating.

[0023] Accordingly, the outer layer is preferably designed as an antimicrobial coated aluminum layer.

[0024] In a preferred embodiment, the outer layer is formed in one piece and completely encloses the filter frame on the outside. In other words, the outer layer extends around the filter frame in the circumferential direction, being formed in one piece. This design increases the sealing effect of the outer layer, since it only needs to be sealed at one joint, if at all. Furthermore, this significantly simplifies the manufacture of the filter frame and thus the entire filter unit, as the filter frame can be machined in one piece, in particular coated with an adhesive, and then folded or bent.

[0025] In a preferred embodiment, the layer arrangement further comprises an inner layer on an inner side of the filter frame. The inner layer is preferably flexible.

[0026] Analogous to the outer layer, the inner layer is preferably arranged on the rigid foam layer. Furthermore, the inner layer is preferably arranged directly on the rigid foam layer.

[0027] Preferably, the outer and inner layers are arranged directly on opposite sides of the rigid foam layer to form a sandwich structure. In other words, the layer arrangement is preferably designed as a sandwich structure, with the rigid foam layer as the core and the outer and inner layers as the facing layers.

[0028] Preferably, the inner layer is designed as a lamination. In other words, the inner layer is bonded to the rigid foam layer by means of lamination.

[0029] Preferably, the inner layer is designed to be waterproof.

[0030] Preferably, the inner layer contains or consists of aluminium.

[0031] Preferably, the inner layer has an antimicrobial and / or antibacterial and / or antiviral coating, in particular a silver ion coating. This measure can further increase the filtering effect of the filter unit against microbes, since the air flowing through it may also pass by the inner layer.

[0032] Accordingly, the inner layer is preferably designed as an antimicrobial coated aluminum layer.

[0033] In a preferred embodiment, the air filter unit has an end frame arranged on one end face of the filter frame. The end frame is preferably L-, U-, or F-shaped. Alternatively, the air filter unit has two end frames arranged on opposite end faces of the filter frame. The end frames are preferably L-, U-, and / or F-shaped. The end frame is an end-face frame. It preferably covers the entire end face of the filter frame. In the case of an L-profile, one leg of the profile is preferably arranged on the inside of the filter frame. In the case of a U-profile, the end frame is preferably inserted into the filter frame, so that the filter frame is located within the U-profile.In the case of an F-profile, the same applies as with a U-profile, except that the additional leg is positioned on the outside to provide a stop for the air filter unit. The front frame can be made of or consist of aluminum.

[0034] Depending on its design, the end frame offers a variety of advantages. First, it provides mechanical protection for the rigid foam layer and thus the filter frame. Furthermore, the end frame can provide an internal stop for a handle guard and / or the filter body. Since the air filter unit must be sealed on the inlet side of, for example, a ventilation duct—usually by pressing it against a rubber gasket—the end frame can also serve as a clamping surface for the screws on the opposite end. Additionally, the end frame can serve as a mounting surface for, for example, a carrying handle.

[0035] In a preferred embodiment, the air filter unit has at least one carrying handle which is attached to the front frame or the two front frames.

[0036] In a preferred embodiment, the air filter unit has at least one RFID chip which is arranged on / in the filter frame, in particular on / in the layer arrangement. Information about the air filter unit, in particular the filter body and / or the filter frame, can be stored on the RFID chip.

[0037] According to the invention, the air filter unit is first manufactured by providing a layered arrangement comprising a rigid foam layer and at least one flexible outer layer on an outer surface of the layered arrangement. The layered arrangement is preferably plate-shaped or designed as a plate / panel. The layered arrangement is pressure-resistant. During processing, the outer surface can, in particular, be the underside of the layered arrangement.

[0038] Depending on the planned design and shape of the filter frame, at least two V-shaped grooves are cut or milled into the layer arrangement to create at least three layer sections, which are connected to each other by the flexible outer layer. The angle and spacing of the V-shaped grooves also depend on the planned design and shape of the filter frame. In the case of a rectangular filter frame, three V-shaped grooves at a 90° angle would be cut or milled into the layer arrangement to create four layer sections. In the case of a square filter frame, the V-shaped grooves would be equidistant.

[0039] Depending on the planned design or shape of the filter frame, appropriately shaped slopes are also added to two opposite layer ends of the

[0040] Layer arrangement cut or milled. In the case of a rectangular or square filter frame, the bevels would have an angle of 45°.

[0041] Furthermore, an adhesive, in particular glue, is applied to an inner side of the layered assembly opposite the outer side. This inner side is the side of the layered assembly with the V-shaped grooves. During processing, this inner side can, in particular, be a top surface of the layered assembly.

[0042] In a first alternative, a filter body for separating substances from the air is placed on one of the layer sections, and then the two opposite layer ends are connected by folding the layer arrangement at the V-shaped grooves to form a filter frame that encloses the filter body and thus creates the air filter unit.

[0043] Alternatively, in a second alternative, the two opposite layers are connected by folding the layer arrangement at the V-shaped grooves to form a filter frame, and then a filter body for separating substances from the air is arranged in the filter frame in such a way that the filter frame encloses the filter body to obtain the air filter unit.

[0044] In a preferred embodiment of the first alternative, after the step of joining the two opposite layer ends, a handle protection element is arranged in the filter frame adjacent to the filter body, and subsequently an end frame, in particular L-, U- or F-shaped, is arranged on an end face of the filter frame adjacent to the handle protection element.

[0045] In a preferred embodiment of the second alternative, prior to the step of arranging the filter body, an end frame, in particular an L-, U- or F-shaped profile, is arranged on an end face of the formed filter frame and a handle protection element is arranged in the filter frame adjacent to the end frame, wherein the filter body is then arranged adjacent to the handle protection element.

[0046] In both alternatives, a further grid protection element can then be arranged on the opposite side in the filter frame adjacent to the filter body, as well as a further end frame, in particular L-, U- or F-shaped, adjacent to the further grid protection element. Drawings

[0047] The invention is explained in more detail below with reference to the accompanying drawings. These show: Figure 1 is a perspective view of an air filter unit according to the invention; Figure 2 is a sectional view AA of the air filter unit made of Fig. 1 Figure 3 shows an intermediate step for the production of an air filter unit; and Figure 4 shows a flowchart of a method according to the invention for the production of an air filter unit.

[0048] Fig. 1 Figure 1 shows a perspective view of an air filter unit according to the invention, which is designated in its entirety by the reference numeral 10. The air filter unit 10 is designed here as a HEPA particulate filter unit 10.

[0049] The air filter unit 10 comprises a filter body 12, or a HEPA filter body 12, for separating airborne particles from the air and a filter frame 14 enclosing the filter body 12. The filter body 12 and the filter frame 14 are rectangular and square, respectively.

[0050] The air filter unit 10 also has a handle protection element 20 on an air inlet side 16 and on an air outlet side 18.

[0051] The air filter unit 10 also has two U-shaped end frames 22, which are arranged on opposite end faces 24 of the filter frame 14. The end frames 22 are inserted into the filter frame 14, so that the filter frame 14 is arranged within the U-profile.

[0052] The air filter unit 10 also has a carrying handle 26, which is attached to the two end frames 22.

[0053] According to the invention, the filter frame 14 has a layer arrangement 28, which is shown in the sectional view AA of Fig. 2 The layer arrangement 28 has a rigid foam layer 30, a flexible outer layer 32 on an outer surface 34 of the filter frame 14 and a flexible inner layer 36 on an inner surface 38 of the filter frame 14.

[0054] The rigid foam layer 30 consists of polyurethane. The outer layer 32 is formed in one piece and completely encloses the filter frame 14 on the outside 34.

[0055] The outer layer 32 and the inner layer 36 are arranged on opposite sides of the rigid foam layer 30, thus forming a sandwich structure with the rigid foam layer 30 as the core and the outer layer 32 and the inner layer 36 as the cover layers.

[0056] The outer layer 32 and the inner layer 36 are designed as a lamination. Both the outer layer 32 and the inner layer 36 are waterproof. The outer layer 32 and the inner layer 36 are formed as aluminum layers 32, 36 and have an antimicrobial coating or silver ion coating (not shown).

[0057] In Fig. 3 A schematic intermediate step 108 for the production of an air filter unit 10 according to the invention is shown. It illustrates how, in a provided plate-shaped layer arrangement 28 with a rigid foam layer 30 and a flexible outer layer 32 (step 102), three equidistant V-shaped grooves 40 at an angle of 90° were cut or milled to obtain four layer sections 42, which are connected to each other by means of the flexible outer layer 32 (step 104). Furthermore, a chamfer 44 at an angle of 45° was cut or milled at two opposite layer ends of the layer arrangement 28 (step 106). Subsequently, an adhesive 46 was applied to an inner surface 38, i.e., the side of the layer arrangement 28 with the V-shaped grooves 40 (step 108).

[0058] Fig. 4Disclosing a method 100 for manufacturing an air filter unit 10, the method 100 comprises a step 102 of providing a layer arrangement 28, in particular a plate-shaped one, with a rigid foam layer 30 and at least one flexible outer layer 32 on an outer surface 32 of the layer arrangement 28. The method 100 further comprises a step 104 of cutting at least two, in particular three, V-shaped grooves 40 into the layer arrangement 28 to obtain at least three, in particular four, layer sections 42, which are / remain connected to one another by means of the flexible outer layer 32. The method 100 also comprises a step 106 of cutting chamfers 44 at two opposite layer ends of the layer arrangement 28. The method 100 further comprises a step 108 of applying an adhesive 46 to an inner surface 38 of the layer arrangement 28.

[0059] In a first alternative, the method 100 comprises a further step of arranging 110 a filter body 12 for separating substances from the air onto one of the layer sections 42 and a subsequent step of connecting 112 the two opposite layer ends by folding the layer arrangement 28 at the V-shaped grooves 40 in order to form a filter frame 14 which encloses the filter body 12 and thus obtains the air filter unit 10.

[0060] In a second alternative, the method 100 further comprises a step of joining 110' the two opposite layer ends by folding the layer arrangement 28 at the V-shaped grooves 40 to form a filter frame 14, and a step of subsequently arranging 112' a filter body 12 for separating substances from the air in the filter frame 14 such that the filter frame 14 encloses the filter body 12 to obtain the air filter unit 10.

[0061] If an embodiment includes an "and / or" connection between a first feature and a second feature, this should be interpreted to mean that, according to one embodiment, the embodiment has both the first feature and the second feature, and according to another embodiment, either only the first feature or only the second feature.

Claims

1. Air filter unit (10), in particular a HEPA filter unit (10), comprising: - a filter body (12) for separating suspended matter from the air; and - a filter frame (14) enclosing the filter body (12); characterized in that the filter frame (14) comprises a layer arrangement (28) having a rigid foam layer (30) and at least one flexible outer layer (32) on an outer side (34) of the filter frame (14).

2. Air filter unit (10) according to claim 1, characterized in that the outer layer (32) is formed in one piece and circumferentially surrounds the filter frame (14) on the outer side (34).

3. Air filter unit (10) according to claim 1 or 2, characterized in that the layer arrangement (28) further comprises an in particular flexible inner layer (36) on an inner side (38) of the filter frame (14).

4. Air filter unit (10) according to any one of the preceding claims, characterized in that: - the outer layer (32) is arranged in particular directly on the rigid foam layer (30); or - the inner layer (36) is arranged in particular directly on the rigid foam layer (30); or - the outer layer (32) and the inner layer (36) are arranged in particular directly on opposite sides of the rigid foam layer (30) to form a sandwich structure.

5. Air filter unit (10) according to any one of the preceding claims, characterized in that the outer layer (32) and / or the inner layer (36) of the layer arrangement (28) is / are designed as a lamination.

6. Air filter unit (10) according to any one of the preceding claims, characterized in that the outer layer (32) and / or the inner layer (36) of the layer arrangement (28) is / are designed to be water-impermeable.

7. Air filter unit (10) according to any one of the preceding claims, characterized in that the outer layer (32) and / or the inner layer (36) of the layer arrangement (28) comprise aluminum or consist of aluminum.

8. Air filter unit (10) according to any one of the preceding claims, characterized in that the outer layer (32) and / or the inner layer (36) of the layer arrangement (28) has / have an antimicrobial and / or antibacterial and / or antiviral coating, in particular a silver ion coating.

9. Air filter unit (10) according to any one of the preceding claims, characterized in that the rigid foam layer (30) comprises a plastic, in particular polyurethane, or consists of a plastic, in particular polyurethane.

10. Air filter unit (10) according to any one of the preceding claims, characterized by: - one front frame (22), in particular L-, U-, or F-profiled, which is arranged on a front side (24) of the filter frame (14); or - two front frames (22), in particular L- and / or U- and / or F-profiled, which are arranged on opposite front sides (24) of the filter frame (14).

11. Air filter unit (10) according to claim 10, characterized by at least one carrying handle (26) which is attached to the front frame (22) or the two front frames (22).

12. Air filter unit (10) according to any one of the preceding claims, characterized by at least one RFID chip which is arranged on / in the filter frame (14), in particular on / in the layer arrangement (28).

13. Air filter system comprising a ventilation pipe and an air filter unit (10) according to any one of the preceding claims, which is arranged in the ventilation pipe for separating substances from the air flowing through.

14. Method (100) for producing an air filter unit (10), in particular according to any one of claims 1 to 12, comprising the steps: - providing (102) an in particular plate-shaped layer arrangement (28) having a rigid foam layer (30) and at least one flexible outer layer (32) on an outer side (34) of the layer arrangement (28); - cutting (104) at least two, in particular three, V-shaped grooves (40) into the layer arrangement (28) to obtain at least three, in particular four, layer sections (42) which are / remain connected to each other by means of the flexible outer layer (32); - cutting (106) bevels (44) at two opposite layer ends of the layer arrangement (28); - applying (108) an adhesive (46) to an inner side (38) of the layer arrangement (28); and - arranging (110) a filter body (12) for separating substances from the air on one of the layer sections (42) and subsequently connecting (112) the two opposite layer ends by folding the layer arrangement (28) at the V-shaped grooves (40) to form a filter frame (14) enclosing the filter body (12), thereby obtaining the air filter unit (10); or connecting (110') the two opposite layer ends by folding the layer arrangement (28) at the V-shaped grooves (40) to form a filter frame (14), and subsequently arranging (112') a filter body (12) for separating substances from the air in the filter frame (14) such that the filter frame (14) encloses the filter body (12), to obtain the air filter unit (10).

15. Method (100) according to claim 14, characterized in that: - after the step of connecting (112) the two opposite layer ends, a handle protection element (20) is arranged in the filter frame (14) adjacent to the filter body (12), and subsequently an in particular U- or F-profiled front frame (22) is arranged on a front side (24) of the filter frame (14) adjacent to the handle protection element (20); or - before the step of arranging (112') the filter body (12), an in particular U- or F-profiled front frame (22) is arranged on a front side (24) of the formed filter frame (14), and a handle protection element (20) is arranged in the filter frame (14) adjacent to the front frame (22), wherein the filter body (12) is subsequently arranged adjacent to the handle protection element (20).

16. Use of a layer arrangement (28) having a rigid foam layer (30) and at least one flexible outer layer (32) on an outer side (34) of the layer arrangement (28) for a filter frame (14) of an air filter unit (10), in particular a HEPA filter unit (10).