WO2017167998A1

WO2017167998A1 - Filtration element for a domestic air purification system

Info

Publication number: WO2017167998A1
Application number: PCT/EP2017/057776
Authority: WO
Inventors: Raphaël AEBISCHER; Sébastien AEBISCHER
Original assignee: Swissair Aps S.A.
Priority date: 2016-04-01
Filing date: 2017-03-31
Publication date: 2017-10-05
Also published as: CN107281826A; FR3049473A1; CN206121332U

Abstract

A filtration element (1, 1a) for a domestic air purification system comprises at least one layer of filtration material (10) of the type of a high-efficiency particulate air filter (HEPA) according to the European EN 1822:2009 standard having a first and a second filtration faces (11, 14), through which moves an air flow to be purified, and an outer side surface (13), the filtration element being characterised in that it comprises a resin (7) that covers at least part of the outer side surface of the layer of HEPA filtration material in order to protect the layer of HEPA filtration material mechanically and/or chemically.

Description

Filtration element for a domestic air purification system

The present invention generally relates to domestic air purification systems. More particularly, the present invention relates to a filter element for a domestic air purification system. The present invention further relates to a filter cartridge containing such a filter element.

Air pollution is a major problem in many cities around the world. It originates from car traffic, heating, agriculture or electricity production and is the cause of many diseases, including respiratory, as well as a large number of premature deaths.

It is known in the prior art domestic purification systems to be installed in a residential area or in a business premises to purify the indoor air and thus promote a healthy atmosphere. However, these devices generally have poor purification performance, thus giving the impression of a healthy indoor atmosphere while high levels of pollution are actually present.

The document US8062403B2 discloses a filtration element comprising several layers or thicknesses of different filtering materials. However, if a filter material layer of the high efficiency particulate air filter (HEPA) type is provided, manufacturing problems may arise due to the great fragility of this type of filtration material. The aforementioned document does not propose any solution to allow easy and safe manufacture, that is to say without deteriorating the filtering material of the high efficiency particulate air filter (HEPA) type. In addition, WO96 / 04063 discloses an ULPA filter, i.e., an ultra-low particulate air filter.

An object of the present invention is to meet the disadvantages of the prior art and in particular to provide a filter element capable of providing optimum purification performance when used in a domestic air purification system, while not posing no additional constraints during manufacture.

An additional object of the present invention is to provide a filter cartridge complying with standard NF 536 concerning the performance of domestic air purifiers.

For this purpose, a first aspect of the invention relates to a filtration element for a domestic air purification system, said filtration element comprising:

A first filtration stage provided with at least a first layer of filtering material of the high efficiency particulate air filter (HEPA) type according to the European standard EN 1822: 2009 having:

a first and a second filtration face each arranged to be traversed by an air stream to be purified, an external lateral surface,

A second filtration stage comprising a second layer of filtration material (20) arranged to be traversed by the stream of air to be purified, that is to say arranged facing one of the filtration faces of the first stage; ,

wherein the second layer of filtration material comprises activated carbon and

wherein the filter element comprises a resin at least partially covering said outer side surface of the first stage material layer so as to mechanically and / or chemically protect said first stage filter material layer. By For example, the resin can form a 4 mm thick layer and ideally covers the entire outer side surface of the first stage filtration material layer or HEPA.

Advantageously, the lateral face connects the two filtration faces. The manipulations carried out during the production of the filter element according to the present invention are without risk for the filter material layer of the HEPA type, because the resin arranged between, or still connecting, the first and the second filtration face protects the lateral surface of the mechanical and / or chemical attacks, even if an operator directly touches this lateral surface with bare hands. As a result, the layer of HEPA material is preserved from physical damage during manufacture of the filter element, such as punctures or tears that directly affect filtration performance. In addition, the layer of HEPA filtration material is also protected from chemical and / or biological contamination, especially in the event of improper storage before or during the manufacture of the filter element, which prevents secondary contamination of the purified air by the release of contaminants when the filter element is used. Moreover, such a resin layer also makes it possible to prevent air leakage by the external lateral surface and thus to force air through the entire thickness of the filter material. The presence of resin is therefore advantageous to allow optimal air purification by the filter element.

In addition, such a configuration of the filtration element, comprising a first filtration stage and a second filtration stage makes it possible to integrate a large quantity of activated carbon into the second filtration stage, thus enabling filtration and optimal purification. air passing through the filter. This allows to provide more activated carbon compared to the inclusion in the first stage high efficiency, HEPA type.

Advantageously, a periphery of the first face and / or the second filtration face is also covered with said resin. This allows easy handling of the HEPA filtration material layer before and during the manufacture of a filter element containing said layer, while preserving mechanical and chemical degradations. In addition, the arrangement of the resin on the periphery of the filtration faces makes it possible to limit the phenomena of reflux which can disturb the purification operation of the air flow.

Advantageously, the second filtration stage is positioned upstream of said first filtration stage comprising said at least one layer of HEPA filtration material in the direction of the air stream to be purified. This arrangement makes it possible to retain the molecules, bacteria and viruses without causing secondary pollution of the air filtered by particles emitted by the activated carbon, the latter being filtered by the layer of HEPA filtration material.

Advantageously, the second stage consists of a layer of compacted active carbon, said activated carbon being for example of C3 or C5 type.

Advantageously, the filtration element according to the present invention also comprises a third layer of filtration material having two filter faces and disposed upstream of the second layer of filtration material in the direction of the airflow to be purified, said third layer of filtration material being for example F7 type according to the European standard EN 779: 2012. This makes it possible to carry out a prefiltration step with respect to said second layer of filtration material, in order to avoid a rapid saturation of the second filtration layer composed of activated carbon and thus to increase the service life of the filtration element.

Similarly, the filter element according to the present invention may comprise a fourth layer of filtration material having two filter faces and disposed upstream of the third layer of filtration material in the direction of the air flow to be purified, said fourth layer of filtration material being for example of the M5 type according to the standard European EN 779: 2012. This layer makes it possible to carry out a first filtration step with respect to the other filtration layers and is particularly advantageous in the case of the purification of a highly charged particulate atmosphere, in order to further increase the service life of the filter element. filtration.

Advantageously, the resin forms a seal between the adjacent peripheries of the filter faces of at least two layers of filtration material to at least partially provide a radial seal with respect to the air stream to be purified. The resin thus limits the radial air leaks, to or from outside the filter element, between the two layers of filtration material, which maintains the volume of filtered air and optimizes the quality of the purification.

Advantageously, the resin forms a seal between a periphery of a filtration face of said at least one layer of HEPA filtration material and an adjacent periphery of a filtration face of said second layer of filtration material. to at least partially ensure a radial seal with respect to the flow of air to be purified.

Similarly, said resin may also form a seal between a periphery of a filtration face of said fourth layer of filtration material and a periphery of a filtration face of said third layer of filtration material to ensure at least partially a radial seal with respect to the air stream to be purified.

A second aspect of the invention relates to a filter cartridge for a domestic air purification system, characterized in that it comprises a sealed housing having a first and a second face each arranged to be perforated during installation in said domestic air purification system, and in that said sealed housing contains a filter element. This sealed case may include a coated tape on its outer side surface. It preserves the filter element from pollution present in the storage environment before its use as well as mechanical damage related to the transport and handling of the filter cartridge. In particular, in the case where the filter element contains activated carbon, it can be preserved oxygen for a much longer period, which is advantageous when the cartridge is stored for several months before being used . The pierceable faces may be perforated during the introduction of the cartridge into a domestic air purification system by perforation elements included in this system, to allow the flow of air to pass through said filter cartridge. air. Such a filter cartridge allows, in addition, a facilitated implementation in a domestic air purification system. After use, such a cartridge can be easily removed without any contact with the filtration materials soiled by the pollution particles.

For example, the filter element contained in the filter cartridge may be a filter element according to the first aspect of the invention.

Advantageously, the filter cartridge comprises resin arranged so as to provide a seal between said sealed housing and the filter element and / or a retention of said filter element in said sealed housing. This allows optimal purification performance, since the filtered airflow can not pass between the filter element and the inner surface of the sealed housing and therefore can not escape the purification operation performed by the filter cartridge.

Advantageously, the filter cartridge may be provided with an identification device, for example a radio identification device (RFID), so as to ensure its origin and to control its storage time before use.

The cartridge may also be provided with a mechanical positioning device on its outer surface, such as pins or fingerprints, so as to ensure the origin of the filter cartridge as well as than its positioning within the domestic air purification system. Such a mechanical keying system also helps the user to correctly position the cartridge and can avoid positioning it upside down, for example. Advantageously, the filter cartridge may be provided on its outer wall with sealing elements intended to ensure a seal such as a seal or a rim or shoulder of elastic material, with complementary elements of the domestic purification system. when the filter cartridge is inserted into such a system. A final aspect of the invention relates to a domestic air purification system, arranged to receive a cartridge and / or a filter element according to the preceding aspects. The system may also include a mechanism for punching and / or fooling the cartridge.

Other features and advantages of the present invention will appear more clearly on reading the following detailed description of an embodiment of the invention given by way of non-limiting example and illustrated by the appended drawings, in which:

1 represents a filtration element according to the present invention, FIG. 2 represents a filtration cartridge comprising a filtration element according to FIG. 1.

Figure 1 shows a filter element 1 comprising a layer of filtration material 10 of the high efficiency aerial particle type (HEPA), also called very high efficiency filter (THE). This layer of HEPA filtration material 10 is provided with a first filtration face 11 having a periphery 12, an outer lateral surface 13 and a second filtration face 14 having a non-visible periphery in FIG. For example, the air to be purified enters the filter through the first filtration face 1 1, which is then the upstream filtration face, and leaves it through the second filtration face 14, which is then the downstream filtration face. Preferably, the filter faces 11 and 14 have a surface area of 250 to 350 cm ² , for example approximately 325 cm ² . These filter faces January 1 and 14 may be circular as shown in Figure 1 or square. In this case, the width of the square may be 200 to 400 mm, preferably 350 mm. In addition, the layer of HEPA filtration material preferably has a thickness of 30 to 50 mm, preferably 35 to 45 mm and more preferably 40 mm.

The outer lateral filtration surface 13 is covered with a resin that mechanically and / or chemically protects the layer of HEPA filtration material 10. This resin thus protects the layer of HEPA filtration material during its manufacture and storage and allows it to be handled completely. by preserving physical degradations and chemical contaminations. In addition, this resin also has the function of limiting or preventing the flow of air from passing through the outer lateral surface 13. Alternatively, the periphery 12 of the first filtration face 11 and / or the periphery of the second filtration face 14 are also covered with said resin.

The high efficiency aerial particle type (HEPA) filtration material is typically a material made of an intermingled fiber arrangement. For example, the fibers may be composed of optionally obtained glass fibers from recycled glass or alternatively natural fibers such as cellulose, as supplied by Unifil AG, Niederlenz, Switzerland.

For example, the HEPA type filtration material layer is made of fiberglass and has a high porosity, from 70% to more than 99% and preferably more than 90%, for example more than 95%. In addition, the fiber size is 100 nanometers to 100 microns. Many filters of this type are known from the prior art and are part of the general knowledge of the skilled person. This layer of filtration material is also preferably pleated and an example of such a layer is described in US5993501 which is incorporated by reference, and in particular columns 4 and 5.

Preferably, the layer of HEPA filtration material meets the European standard EN 1822: 2009. According to this standard, the filter is preferably class "high efficiency particulate air filter" or higher, that is to say at least class H13 having a purification efficiency of 99.95% and a penetration of 0, 05% in integral values measured with particles of diameter greater than or equal to 0.3 μιτι. The initial pressure drop caused by this filtration layer may be 120 Pa for a nominal flow rate of 300 m ³ / h or 160 Pa for a nominal flow rate of 500 m ³ / h. This HEPA filtration material can filter particles up to 10 nm. This type of filtration class thus contributes to efficient purification when the filter element is used within a domestic air purification system. The resin covering the outer lateral surface 13 and possibly the peripheries of the filtration faces 11 and 14 is preferably a resin impervious to air and resistant to at least abrasion. For example, such a resin can be obtained from natural products such as propolis, Candelilla wax, Canauba wax or coniferous resin such as maritime pine or cypress. Alternatively, the resin may also be an artificial resin including, for example, paraffin, acrylic, polyester, polyvinyl chloride or preferably silicone such as a resin 732 from the manufacturer Dow Corning Corporation. Such a resin may be crosslinked or not. It is applied to the outer lateral surface 13 and possibly to the peripheries of the filtration faces 11 and 14 by a known method, such as soaking or depositing. The thickness of the resin layer is 2 to 6 mm and preferably 4 mm.

Figure 2 shows a filter cartridge 2 having a filter element 1a comprising the filter material layer HEPA 10 described in Figure 1. The filter element 1a of the filter cartridge 2 comprises a second filter material layer 20 located upstream of the layer of HEPA filter material 10, a third layer of filter material 30 upstream of the layer filtration material 20, as well as a fourth layer of filtration material 40 placed upstream of the third filtration layer 30, each filter layer having two filter faces as shown in FIG. 2. Thus, each filtration layer represents an individual or independent filtration stage, or an individual filtration chamber, that is to say not integrated with another filtration layer.

The terms "downstream" and "upstream" refer to the flow of air to be purified. The filter cartridge 2 further comprises a housing 3 comprising a lateral surface 7, a first face 4 and a second face 5, both faces being made of a perforable material. The filter element 1a comprising the filter material layers 10, 20, 30, 40 is contained in the housing 3.

The second layer of filtration material 20 is an activated carbon layer. This active carbon is of the C3 or preferably C5 type, as supplied by Unifil AG, Niederlenz, Switzerland and its role is to retain molecules, viruses and bacteria up to nanometer sizes. Activated carbon is compacted here to provide optimum filtration performance.

Preferably, this second layer of filtration material 20 has a surface similar to the layer of HEPA material and a weight of coal 400 and 600 g, preferably 500 g. For example, the thickness of this second layer of filtration material 20 is 8 to 12 mm and preferably 10 mm. Thus, having active carbon in compacted form in a second filtration stage, i.e. in the form of a second and different filtration layer 20 not integrated with the first filtration layer 10 comprising the layer of material filtration HEPA type, can significantly increase the amount of activated carbon and thus achieve filtration and air purification much more.

The third layer of filtration material 30 is a fine filter capable of filtering fine particles according to the European standard EN 779: 2012, for example of the F7 type as supplied by Unifil AG, Niederlenz, Switzerland, that is to say having a mean efficiency (Em) of 80 to 90% and a minimum efficiency of 35%, these two values being measured with particles of 0.4 μιη. In addition, this third layer of filtration material 30 causes an initial pressure drop of 39 Pa at a flow rate of 12.7 m / s.

This third layer of optional filtration material 30 has for example a surface similar to the surface of the filtration faces of the layer of HEPA material and a thickness of 2 to 8 mm and preferably 5 mm.

The fourth layer of filtration material 40 is a fine filter capable of filtering the average particles according to the European standard EN 779: 2012, for example of the M5 type, as supplied by Unifil AG, Niederlenz, Switzerland, that is to say having a mean efficiency (Em) of 40 to 60% with mean particle sizes of 0.4 μιη. In addition, this fourth filtration layer 40 causes an initial pressure drop of 90 Pa at a flow rate of 1.5 m / s.

This fourth layer of optional but preferred filtration material 40 has for example a surface similar to the surface of the filtration faces of the layer of HEPA material and a thickness of 10 to 20 mm, preferably 15 mm. Each layer of filtration material is separated from the other layers of filter material by separating members 6. These separating members 6 further retain the layer of HEPA filtration material 10 located at the bottom of the filter element 1a. (Downstream layer) as well as the fourth filtration layer 40 located at the top of the filter element 1a (upstream layer), as shown in FIG. 2. The function of the separating elements 6 is therefore to physically retain each layer of filtration material in order to avoid damage caused by shocks or friction between filter layers. The separating elements 6 consist of a sheet of mesh material or openwork, such as a mesh of plastic or metal, a canvas or a sheet of perforated paper. Preferably, the separating elements 6 are made of recycled and / or recyclable material, such as polypropylene mesh.

The filtration cartridge 2 further comprises a resin 7 as described above. This resin mechanically and chemically protects the layers of filtration material 10, 20, 30, 40 before assembly in the filtration cartridge 2. In addition, the resin 7 ensures a fixation of each filtration layer to the housing 3. Finally, the resin provides a radial seal to each layer of filtration material and a radial seal between each layer of filtration material. The presence of the resin 7 around the second filtration layer 20 is not mandatory because it contains compacted activated carbon.

The housing 3 is made of a rigid material, preferably airtight. For example, the housing 3 may be made of cardboard or plastic, preferably recycled, such as polypropylene, polyethylene terephthalate and high density polyethylene. The first face 4 and the second face 5 are made of a perforable material, for example of the same nature as that of the housing 3, or aluminum. Preferably, the housing 3 is sealed, that is to say that it can not be opened without physical degradation, for example using tools. The housing 3 helps to protect the filter element 1a before it is used in a domestic purification system. The casing 3 further comprises a 148 mesh woven support fabric tape with a natural rubber and acrylic coated adhesive mass. This adhesive tape helps to seal the housing 3 and to mechanically protect the housing 3 so as to prevent any air leakage caused by perforation or tearing of the housing 3. In operation, when a domestic purification system is equipped with a filtration cartridge 2, a perforation of the first face 4 and the second face 5 of the housing 3 is performed by perforation elements, for example hollow needles or tubes. hollow of said purification system (not shown). The flow of air to be purified is represented in FIG. 2 by the two vertical arrows above the housing 3. The flow of air is conveyed by the purification system to the first face 4 or upstream face of the housing 3. The airflow first enters the fourth layer of filtration material 40 (upstream layer), which retains the medium-sized particles, and then enters the third filtration layer 30 which retains the fine-sized particles. The air flow then passes through the second filter layer 20 retaining the molecules, viruses and bacteria. Finally, the airflow passes through the layer of HEPA filtration material retaining the finest particles. The air flow is then routed outside the filter cartridge 2 through the second face 5 or downstream face by the domestic air purification system.

The arrangement of the layers of filter material within the filter cartridge 2 allows filtering of smaller and smaller particles to the layer of HEPA filter material. The fact of inserting the second filtration layer comprising activated carbon between the layer of HEPA filtration material and the third layer of filtration material makes it possible to retain molecules, viruses and bacteria without polluting the air filtered by particles. emitted by activated carbon. Optimal purification of the air is therefore possible while avoiding clogging a filter material layer too quickly, in order to maintain the service life of the filtration cartridge 2. In addition, the layers of filtration material are also arranged in order of increasing pressure drop in the direction of the air flow, this avoiding reflux phenomena detrimental to the quality of the purification. The resin 7 makes it possible to avoid leaks between the layers of filtration material and thus to contain the flow of air through all the layers of filtration material, which contributes to an optimal purification of the air flow.

Finally, the housing 3 comprising perforable faces 4 and 5 makes it possible to preserve the layers of filtration material before using the filtration cartridge. In particular, the second layer of filtration material composed of activated carbon is preserved from oxygen, which maintains its filtration performance even in the case where the filter cartridge is stored for a long time before use, for example several months .

It will be understood that various modifications and / or improvements obvious to those skilled in the art can be made to the various embodiments of the invention described in the present description without departing from the scope of the invention defined by the appended claims. In particular, reference is made to the shape of the layers of filter material which may be of any suitable shape, such as rectangular or oval. Similarly, the number of filter material layers is not limited to one or four and may include a number of layers of filter material adapted to the air to be purified. For example, a prefilter may be provided above the fourth filtration layer or in the domestic air purification system. Finally, filtration classes and their performance are given only as an example and may be adapted to the air to be purified and the capabilities of the domestic air purification system.

Claims

R EVE NDI CATI ON S

1. A filter element (1, 1 a) for a domestic air purification system, said filter element comprising:

A first filtration stage provided with at least a first layer of filtration material (10) of the high efficiency particulate air filter (HEPA) type according to the European standard EN 1822: 2009 having:

o a first and a second filtration face (1 1, 14) each arranged to be traversed by a stream of air to be purified,

an outer lateral surface (13),

A second filtration stage comprising a second layer of filtration material (20) arranged to be traversed by the flow of air to be purified, wherein the second layer of filtration material (20) comprises activated carbon, and wherein the filter element comprises a resin (7) at least partially covering said outer lateral surface of the filter layer of the first stage so as to mechanically and / or chemically protect said layer of filtration material of the first stage.

Filtration element (1, 1 a) according to claim 1, characterized in that a periphery (12) of the first face (1 1) and / or the second filter face (14) is also covered with said resin (7).

3. Filter element (1 a) according to one of the preceding claims, characterized in that the second filtration stage is positioned upstream of said first stage in the direction of the air flow to be purified.

Filtration element (1 a) according to one of the preceding claims, characterized in that the second stage consists of a layer of compacted activated carbon, said activated carbon being for example of C3 or C5 type.

5. Filtration element (1 a) according to the preceding claim, comprising a third layer of filtration material (30) having two filter faces and disposed upstream of said second layer of filtration material (20) in the flow direction. of air to be purified, said third layer of filter material (30) being for example F7 type according to the European standard EN 779: 2012.

6. Filtration element (1 a) according to the preceding claim, comprising a fourth layer of filtration material (40) having two filter faces and disposed upstream of the third layer of filtration material (30) in the flow direction. of air to be purified, said fourth layer of filtration material (40) being for example of the M5 type according to the European standard EN 779: 2012.

Filtration element (1 a) according to any one of claims 5 and 6, characterized in that said resin (7) forms a seal between the adjacent peripheries of the filter faces of at least two layers of filtration material (10, 20, 30, 40) for at least partially providing a radial seal with respect to the air stream to be purified.

Filtration element (1 a) according to any one of claims 5 and 6, characterized in that said resin (7) forms a seal between a periphery (12) of a filtration face (1 1 ) of said at least one layer of HEPA filtration material (10) and an adjacent periphery of a filtration face of said second layer of filtration material (20) to at least partially provide a radial seal with respect to the flow of air to be purified.

9. Filtration cartridge (2) for a domestic air purification system, characterized in that it comprises a sealed casing (3) having a first and a second face (4,5) each arranged to be perforated during an installation in said domestic purification system of air, and in that said sealed housing (3) contains a filter element (1, 1 a) according to any one of the preceding claims.

10. Filter cartridge (2) according to the preceding claim, characterized in that said resin (7) is arranged so as to ensure a seal between said sealed housing (3) and the filter element (1, 1 a) and / or maintaining said filter element (1, 1 a) in said sealed housing (3).