Technical Domain

The present invention relates to a plant-based air filtration device (100) and its use for filtering ambient air for example a† road walls, train walls or on building fagades, parking slopes, funnel exits or building inferiors as well as a method for filtering ambient air using such a device (100).

Prior art

Air pollution associated with combustion processes of fossil fuels and other chemical processes is a concern of increasing importance in particular in urban areas and city centers. Many solutions have been proposed †o control air pollution, for example through filtration of exhaust gases. However, recently, a new type of solution has been proposed: filtration of air pollutants through wall greening.

For example, US 2017/0273256 to Purdue Research Foundation proposes solutions for cleaning the air within buildings through a device that is fully integrated in the air conditioning system of buildings. In particular, this document describes an indoor bio wall which includes four plan† filter beds arranged one above the other a† four filter levels or tiers†o achieve an overall filter area. Each filter bed and its plants are located in a modularized tray installed in one of the four filter tiers, and each filter bed is preferably removable†o enable plan† and growth media maintenance. The four removable trays fit into a plenum. A back due† is located behind the plenum and draws air through the plenum and its trays. The back due† can be hidden in a wall, close†, or utility area. The air flow through each tier is preferably a combination of horizontal and vertical flows across and through plants located in each tray, and the back due† is configured†o combine the individual air flows (indicated with arrows) from the plan† filter beds into a single outlet including a fan which draws air flow through the bio wall. The structure focuses on applying symmetries†o the back due† which preferably promotes equal air flow through every filter tier. To enable vertical flow through the horizontal filter beds and plants' rhizospheres, the trays are equipped with holes on the bottom surface thereof so that the back due† is able†o draw air downward through each tray and through the plants and growth media contained therein. However, this bio wall is particularly designed for indoor applications which typically involve high manufacturing and high maintenance costs.

Solutions for filtering ambient outdoor air are proposed for example in FR2967550 B1†o Circeo Partners. This document describes an apparatus for producing a wall intended †o be covered with vegetation, comprising a liquid storage tank, in particular of rainwater, a cage extending vertically for holding a substrate in order†o power plants, means for securing the cage on a vertical wall of the reservoir; and means for watering plants cultivated on a substrate, the means for watering being supplied with water by the water tank. However, this document does no† disclose any active airflow management for example by means of a ventilator or a fan.

DEI 02013107786 to Stefan Brandhors† relates †o a wall greening system with moss on a fibrous support. I† suggests also the use of a temperature sensor†o optimize irrigation. However, this document does no† disclose any active airflow management for example by means of a ventilator or a fan. DE 20 201 7 104 038 U 1 †o Freund GmbH filed on 06.07.201 7 discloses a wall greening system with one or more support multi-layer materials using moss on a nonwoven support of 10-50 mm thickness, for example polyester or polyamide fibers and an irrigation system in view of an even distribution of the water to the moss on the nonwoven support. However, this document does not disclose any active airflow management for example by means of a ventilator or a fan.

NL2005218 to Kluiver Pieter Paul is directed at a treatment device for purifying air and/or water comprising an active airflow management for example by means of a ventilator or a fan. In particular, this document discloses a device comprising one or more modules and a framework, a module coupling means for coupling the individual modules to form a structure of modules, and attachment coupling means for coupling at least a part of the modules to a wall, roof and/or a ground surface. A fan generates an airflow which enters from the top, moves down and exits laterally through the plant support. The plant support thereby distributes the air pressure of the airflow. However, it is not shown, how the active airflow is managed.

There is therefore a general need to provide improved air filtration devices for outdoor applications that show an improved filtration capacity of ambient air for example at road walls, train walls or on building fagades, parking slopes, tunnel exits or building interiors, whilst having favorable production and maintenance costs.

Brief summary of the invention

The present inventors have found an improved way of irrigating and ventilating moss walls in particular for outdoor wall greening and air filtration by using air distribution ducts with openings covered by a plant-based multi-layer material. The air distribution duct is coupled with an airflow generation component in the form of a symmetric frustrum that is tapered towards bottom part. Symmetries in the tapered design allow for improved vertical and lateral distribution of the air thereby also improving the distribution of the wafer from the wafer irrigation system.

Accordingly, the present invention is directed a† a plant- based air filtration device ( 100) comprising a. One or more plant-based modules ( 10) comprising a module frame ( 1 1 , no† shown) and one or more plant- based multi-layer materials ( 12) , the multilayer material ( 12) comprising

• A support layer ( 13) and a substrate layer ( 14), or

• An integrated substrate and support layer ( 14) and a plant-based layer ( 15);

b. An irrigation system (20) comprising a water supply (21 ) and a plurality of water distributing means (22) configured in operational mode†o distribute water†o each of the plant- based multi-layer materials;

c. An air distribution due† (30) having one or more front openings (320) that in operational mode are covered by the plant-based multi-layer materials ( 12) allowing for the air†o travel laterally from the air distribution due††o and through the plant-based layer ( 15);

d. An airflow generation component (40) in the form of a symmetric frustrum that is tapered towards the bottom par† (41 ) of the airflow generation component (40); e. An airflow generation means (60) optionally being covered by a sediment filtration means (70) and preferably being located a† the bottom par† (41 ) of the airflow generation component (40) ;

Wherein in operational mode, - in a firs† step, ambient air (90) enters optionally through the sediment filtration means (70) ,

- In a second step, ambient air (90) is accelerated by the airflow generation means (60) vertically towards the air distribution duct (30) to obtain a vertical airflow (92) in a way to create overpressure in the air distribution duct as compared to ambient air pressure (30) and

- In a third step, the vertical airflow (92) exits the air distribution duct (30) through the front openings (320) to obtain a lateral airflow (93) thereby distributing the water from the water distribution means (22) laterally to and within the substrate layer ( 14) and the plant-based layer ( 1 5) and exits the plant-based air filtration device ( 100) to obtain a filtered airflow (94) .

According to an aspect of the invention, there is provided a plant-based air filtration device ( 100) comprising a. One or more plant-based modules ( 10) comprising a module frame ( 1 1 ) and one or more plant-based multi layer material ( 12) comprising

• a support layer ( 13) , a substrate layer ( 14) , or

• an integrated support and substrate layer ( 14) and a plant-based layer ( 1 5) wherein said plant- based layer ( 1 5) is a moss layer;

b. An irrigation system (20) comprising a water supply means (21 ) and a plurality of water distributing means (22) configured†o distribute water to each of the one or more plant-based multi-layer materials ( 12) ;

c. An air distribution duct (30) having one or more front openings (320) which are adapted to be covered by the one or more plant-based multi-layer materials ( 12) allowing for the air to travel essentially laterally or laterally from the air distribution duct to and through the plant-based layer ( 1 5) ;

d. An airflow generation component (40) in the form of a symmetric frustrum that is tapered towards the bottom part (41 ) of the airflow generation component (40); e. An airflow generation means (60) optionally being covered by a sediment filtration means (70) and being located in the airflow generation component (40);

wherein said airflow generation component (40) is configured to allow ambient air (90) to enter, optionally though said sediment filtration means (70) , wherein said airflow generation means (60) are configured to accelerate said ambient air (90) substantially vertically or vertically towards said air distribution duct (30) to obtain a substantially vertical or vertical airflow (92) thereby creating overpressure in said air distribution duct (30) as compared to ambient air pressure, and wherein said air distribution duct (30) is configured to exit said substantially vertical or vertical airflow (92) through said front openings (320) to obtain a substantially lateral or lateral airflow (93) thereby distributing the water from the water distribution means (22) substantially laterally or laterally thereto and within the substrate layer ( 14) and the plant-based layer ( 1 5) and to exit the plant-based air filtration device ( 100) to obtain a filtered airflow (94) . In another embodiment, the air distribution duct (30) is formed by a one or more air distribution modules (300) having one or more front openings (320) and one or more fop openings (310), the openings being covered by a one or more plant-based multi-layer materials.

In another embodiment, 80 volume% or more of the airflow generated by the airflow generation means (60) exits the plant-based air filtration device ( 100) through the front openings of the distribution due† (30) .

In another embodiment, the 95 volume% or more of the airflow generated by the airflow generation means (60) exits the plant- based air filtration device ( 100) through the front openings of the distribution due† (30) .

In another embodiment, the plant-based air filtration device ( 100) further comprises a remote-control system allowing for remote control of airflow and irrigation.

In another embodiment, each of the plant-based modules comprises two or more moss multi-layer materials rotatably fixed†o the module frame in a way that they are openable like doors.

In another embodiment, the airflow generation component (40) is a square or rectangular frustrum.

In another embodiment, the support layer ( 13) of the plant- based multi-layer material is a grid.

In another embodiment, the substrate ( 14) layer is a nonwoven or woven textile.

In another embodiment, the airflow generation means (40) is a centrifugal fan or ventilator.

In another embodiment, the water distributing means (22) is a droplet irrigation or soaker hose.

In another embodiment, the plant-based air filtration device ( 100) further comprises an air flow control system for controlling the air moving through the air distribution duct (30) , and adjusting air flow based on air qualify, pressure within the plant-based air filtration device, and health of the plant-based layer.

In another embodiment, the air distribution due† (30) further comprises means for adjusting airflow substantially laterally or laterally through the plant-based multi-layer materials.

A further object of the invention is the use of a plant-based air filtration device ( 100) to filter ambient air for example a† road walls, train walls or on building fagades, parking slopes, tunnel exits, or building interiors, wherein ambient air entering through the sediment filtration means (70) is accelerated by the airflow generation means (60) substantially vertically or vertically towards the air distribution due† (30) thereby pushing the air through the front openings of the air distribution due† (30) and distributing the water from the water distribution means (22) substantially laterally or laterally†o and within the plant-based layer ( 1 5) of the plant-based multi-layer materials ( 12) .

A further object of the present invention is a method of filtering air in need of filtration, the method comprising: a. Providing a plant-based air filtration device ( 100) comprising

- One or more plant-based modules ( 10) comprising a module frame ( 1 1 ) and one or more plant-based multi-layer materials ( 12) the multilayer material ( 12) comprising

- a support layer ( 13) , a substrate layer ( 14) , or

- an integrated support and substrate layer ( 14) and a plant-based layer ( 15) - An irrigation system (20) comprising a water supply (21 ) and a plurality of wafer distributing means (22) configured in operational mode†o distribute wafer †o each of the plant-based multi-layer materials;

- An air distribution due† (30) having one or more front openings (320) that in operational mode are covered by the plant-based multi-layer materials ( 12) allowing for the air†o travel substantially laterally or laterally from the air distribution due† †o and through the plant-based layer ( 15);

- An airflow generation component (40) in the form of a symmetric frustrum that is tapered towards the bottom par† (41 ) of the airflow generation component (40) ;

- An airflow generation means (60) optionally being covered by a sediment filtration means (70) and being located a† the bottom par† (41 ) of the airflow generation component (40) ; b. Accelerating ambient air entering through the opening of the airflow generation component, preferably covered by the sediment filtration means (70) by the airflow generation means (60) substantially vertically or vertically towards the air distribution due† (30) in a way†o create overpressure in the air distribution due† as compared†o the ambient air pressure (30) thereby pushing the air through the front openings of the air distribution due† (30) and distributing the water from the water distribution means (22) substantially laterally or laterally†o and within the plant-based layer ( 1 5) of the plant-based multi-layer materials ( 12) . Other embodiments according to the present invention are mentioned in the appended claims.

Detailed description of the invention

Other characteristics and advantages of the present invention will be derived from the non-limitative following description, and by making reference to the drawings and the examples.

For the purpose of the invention, the wording "substantially vertical" refers herein -depending on the application- to a direction which may deviate from the vertical axis by an angle up to 10°, up to 20°, up to 35° and even up to 45° with reference to said vertical axis. Similarly, the wording "substantially lateral" refers herein -depending on the application- to a direction which may deviate from the lateral direction by an angle up to 10°, up to 20°, up to 35° and even up to 45° with reference to said lateral direction.

The plant-based air filtration device ( 100) comprises a one or more of plant-based modules ( 10) , for example 2, 4, 6, 8, 10, 12, 14 or more plant-based modules. The number and size of plant-based modules may vary widely according to the size and performance of the airflow generation means, and dimensions of the air distribution duct and of the airflow generation component as well as the airflow resistance created by the plant-based multi-layer materials. Preferably, the plant-based air filtration device ( 100) consists of 4 plant-based modules. Several plant-based modules are coupled to a module frame with coupling means.

The plant-based module comprises one or more plant- based multi-layer materials ( 12) , for example 1 , 2, 3 or four plant-based multi-layer materials, preferably 2 plant-based multi-layer materials. Each plant-based multi-layer material comprises a support layer ( 13), a substrate layer ( 14) , preferably being a polymeric nonwoven material, and a plant-based layer ( 15) , the plant-based layer preferably being a moss layer. In another embodiment, each of the plant-based modules comprises one or more, preferably two plant-based multi-layer materials in the form of panels rotatably fixed†o the module frame in a way that they are openable like doors. In this way, maintenance of the plant-based air filtration system ( 100) is facilitated through easier local access†o for example the wafer distribution means or the electronic parts.

An irrigation system (20) ensures the supply of the plant- based multi-layer materials with wafer. The irrigation system comprises a wafer supply (21 ) and a plurality of wafer distributing means (22) , preferably a drip irrigation system or soaker hose. The irrigation system (20) is configured in operational mode†o distribute wafer†o each of the plant-based multi-layer materials. In case of drip irrigation system, a plurality of perforated wafer hoses or wafer-permeable soaker hoses are distributed a† the fop or within the plant-based multi-layer materials or within the substrate layer in order†o ensure correct watering of the plant-based layer and the substrate layer.

The air distribution due† (30) comprises one or more front openings (320) that in operational mode are covered by the plant- based multi-layer materials ( 12) and allow for the air †o travel substantially laterally or laterally from the air distribution due††o and through the plant-based layer ( 15) . The air distribution due† is preferably formed of two or more air distribution modules. In a preferred embodiment, the air distribution due† is formed of four air distribution modules.

The air distribution modules are connected with each other using coupling means, for example a coupling frame.

The air distribution modules have one or more front openings, for example 1 , 2, 3 or 4 front openings, preferably one front opening and one or more top openings for example 1 , 2, 3 or 4 top openings, preferably one fop opening and one or more bottom openings for example 1 , 2, 3 or 4 bottom openings, preferably one bottom opening. Preferably, the air distribution modules have closed or air-tight side walls and closed or air-tight back walls. When assembled, the air distribution modules form one or more air distribution ducts. The size of the top openings, the front openings and the bottom openings may vary according to the size and performance of the airflow generation means, and dimensions of the air distribution duct and of the airflow generation component as well as the airflow resistance by created by the plant-based multi-layer materials. For example, the size of the top, the bottom and of the front openings may be 50 surface area% or more, 60 surface area% or more, 70 surface area% or more, 90 surface area% or more, or 95 surface area% or more as compared to the surface of the top wall, the bottom wall or the front wall of the air distribution module.

The plant-based air filtration device further comprises an airflow generation component (40) in the form of a symmetric frustrum that is tapered towards the bottom part (41 ) of the airflow generation component (40) . The term frustrum describes a geometric form whose top wall has a bigger surface area than the bottom wall, the bottom and top wall being essentially parallel. The term symmetric also comprises essentially symmetric embodiments with variations around the symmetry axis as long as the even airflow management of the present invention is not materially impacted by the asymmetry. The symmetry is important for the even distribution of the substantially vertical or vertical airflow and substantially lateral or lateral airflow across the plant-based modules. The frustrum preferably is square, i.e. angular or polygonal. However, round embodiments are also possible. The airflow generation component is closed at the bottom wall and the side walls preferably in an essentially air-tight manner. However, the front wall of the airflow generation component has an opening. The opening is preferably covered by a sediment filtration means and that allows ambient air to enter. The top wall of the airflow generation component has one or more openings, preferably one opening. The dimension of the opening of the top wall may vary according to the required airflow. For example, the opening may be 50 surface area% or more, 60 surface area% or more, 70 surface area% or more, 90 surface area% or more, or 95 surface area% or more as compared to the surface of the top wall of the airflow generation component.

The airflow generation component is coupled to the air distribution duct through coupling means, for example a coupling frame, in a way that the top opening is attached to the bottom opening of the air distribution duct.

The coupling of airflow generation component and air distribution duct is preferably essentially airtight in order to avoid air loss other than the front openings of the air distribution duct.

The airflow generation component comprises an airflow generation means (60) . Preferably the airflow generation means is a ventilator or fan or any other means capable of accelerating air.

The airflow generation means is preferably covered by a sediment filtration means (70) . The sediment filtration means may be a grid that filters objects, for examples leaves of trees, insects or stones from entering the airflow generation component. The airflow generation means preferably is located at the bottom part (41 ) of the airflow generation component (40) . However, the airflow generation means may be located at other parts of the airflow generation component (40) as long as the location allows for the building up of pressure in the air distribution duct (30) in operational mode.

In operational mode, ambient air (90) enters through the opening, preferably covered by said sediment filtration means (70) , is accelerated by the airflow generation means (60) substantially vertically or vertically towards the air distribution due† (30) to obtain a substantially vertical or vertical airflow (92) in a way †o create overpressure in the air distribution due† as compared†o ambient air pressure and exits the air distribution due† (30) through the front openings (320) to obtain a substantially lateral or lateral airflow (93) thereby distributing the water from the water distribution means (22) substantially lateral or laterally†o and within the substrate layer ( 14) and the plant-based layer ( 1 5) and exits the plant-based air filtration device ( 100) to obtain a filtered airflow (94) .

I† is important that the plant-based air filtration device is essentially airtight in the sense that 80 volume% or more, preferably 90 volume%, even more preferably 95 volume% or more, of the airflow generated by the airflow generation means (60) exits the plant-based air filtration device ( 100) through the front openings of the distribution due† (30) .

In another embodiment, the plant-based air filtration device ( 100) further comprises an air flow control system for controlling the air moving through the air distribution due† (30) , and adjusting air flow based on air quality, pressure within the plant-based air filtration device, humidity, wind, temperature and health of the plant-based layer. I† can also be activated or controlled remotely.

In another embodiment, the air distribution due† (30) further comprises means for adjusting airflow substantially laterally or laterally through the plant-based multi-layer materials.

A further object of the invention is the use of a plant-based air filtration device ( 100) to filter ambient air for example a† road walls, train walls or on building fagades, parking slopes, tunnel exits, or building interiors, wherein ambient air entering through the opening of the airflow generation component, preferably covered by the sediment filtration means (70) is accelerated by the airflow generation means (60) substantially vertically or vertically towards the air distribution duct (30) thereby pushing the air through the front openings of the air distribution duct (30) and distributing the water from the water distribution means (22) substantially laterally or laterally to and within the plant-based layer ( 1 5) of the plant-based multi-layer materials ( 12) .

Detailed description of the drawings

Figure 1 shows a schematic front view of the plant-based air filtration device ( 100) wherein the sediment filtration means (70) is removed in order to make the airflow generation means (60) visible. Figure 1 shows an embodiment with four plant-based modules consisting each of two plant-based multi-layer materials. The airflow generation means is a fan. The fan or ventilator accelerates the pre filtered ambient air that entered the device ( 100) through the sediment filtration means (not shown in Figure 1 ) . The accelerated air is pushed through the symmetric frustrum using symmetries to optimize airflow management. The symmetric frustrum is coupled with the air distribution duct. The air distribution duct is constituted of four air distribution modules. Each air distribution module presenting top and bottom openings to allow for the airflow to move vertically up the air distribution duct. As the top opening of the upper air distribution module is essentially closed, the vertical airflow is forced to pass through the front openings of the air distribution modules. The front openings have essentially the same size as the front wall, thereby allowing a maximum of the airflow to pass vertically through the plant-based modules. The plant-based modules consist of a grid, covered by a moss on a nonwoven. Though Figure 1 shows a support layer and a substrate layer, these two layers may also be integrated into one substrate and support layer. The airflow resistance of the plant-based modules is kept sufficiently low†o allow for the lateral airflow. A drop or drip irrigation system is placed within the plant-based multi-layer materials. As the vertical airflow passes through the plant-based multi-layer materials, the water droplets formed by the drop irrigation system may be distributed through the substrate layer and the plant-based layer, here a moss on a nonwoven substrate layer.

Figure 2 is a schematic front view of the plant-based air filtration device (100) shown in Figure 1 wherein the sediment filtration means (70) is covering the airflow generation means (60).

Figure 3 is a schematic perspective view of the plant-based air filtration device (100) shown in Figure 1. Whilst each of the modules has top openings so that when arranged vertically, an airduct is formed, the top openings of the upper modules usually are closed to force the air laterally through the plant-based multi-layer materials. Flowever, in some embodiments, parts of the top openings of the upper module may be partially open, for example, the top opening of the upper module may be 50 surface area % or more closed, preferably, 75 surface area % closed, even more preferably 90 surface area % closed, even more preferably 99 surface area % closed.

Figure 4 is a schematic top view of the plant-based air filtration device (100) shown in Figure 1 , where the top openings of the upper modules are open.

Figure 5 is a schematic side view of the plant-based air filtration device (100) shown in Figure 1. The side walls and the back walls (not shown) of the air distribution duct are closed in order to force the airflow generated by the airflow generation means through the plant-based multi-layer materials.

Figure 6 is a schematic view of the airflow through the plant-based multi-layer material (12). Ambient air (90) enters through the opening of the airflow generation component, preferably covered by sediment filtration means (70), is accelerated by the airflow generation means (60) vertically towards the air distribution due† (30) to obtain a vertical airflow (92) and exits the air distribution due† (30) through the front openings (320) to obtain a lateral airflow (93) thereby distributing the water from the water distribution means (22) laterally†o and within the substrate layer (14) and the plant-based layer (15) and exits the plant-based air filtration device (100) to obtain a filtered airflow (94).

The following reference numerals are used in the drawings and throughout the description for facilitating claim interpretation and are by no means mean††o limit the scope of the present invention†o the embodiments shown in the drawings and the dimensions and technical design choices shown therein.

100 Plant-based air filtration device according†o the invention

10 Plant-based module

1 1 Module frame (no† shown)

12 Plant-based multi-layer material

13 Support layer

14 Substrate layer

15 Plant-based layer

20 Irrigation system

21 Water supply means (no† shown)

22 Water distribution means

30 Air distribution due†

31 Back wall of air distribution due† (30)

32 Side wall of air distribution due† (30)

300 Air distribution module

310 Top opening of the air distribution module (300)

320 Front opening of the air distribution module (300), no† shown

40 Airflow generation component 41 Bottom part of the airflow generation component

50 Power supply means

60 Airflow generation means

70 Sediment filtration means

80 Stabilization means

90 Ambient air

92 Vertical airflow

93 Lateral airflow

94 Filtered air

Drawinqs.-

Figure 1 is a schematic front view of the plant-based air filtration device (100) wherein the sediment filtration means (70) is removed in order†o make the airflow generation means (60) visible.

Figure 2 is a schematic front view of the plant-based air filtration device (100) wherein the sediment filtration means (70) is covering the airflow generation means (60).

Figure 3 is a schematic perspective view of the plant-based air filtration device (100).

Figure 4 is a schematic fop view of the plant-based air filtration device (100).

Figure 5 is a schematic side view of the plant-based air filtration device (100).

Figure 6 is a schematic view of the airflow through the plant-based multi-layer material (12).

In the drawings, the same reference numbers have been allocated†o the same or analog element I† should be understood that the present invention is not limited to the described embodiments and that variations can be applied without going outside of the scope of the appended claims.