FILTER BAG

Abstract

The present invention relates to a filter bag (1) for the decontamination of a polluted gas, mainly characterized in that it comprises: - a sealed inner bag (2), comprising a lateral surface (4), a base (5) and a top surface (6) which delimit an internal space (7) adapted to contain a filter medium (24), the inner bag (2) further comprising an inlet sleeve (8) for the polluted gas into the inner bag (2) adapted to be connected to a source of polluted gas, and an outlet sleeve (9) for the purified gas out of the filter bag (1), - an outer casing (3) adapted to receive the inner bag (2), which surrounds at least the base (5) and the lateral surface (4) of the inner bag (2), the outer casing (3) comprising a first opening (18) adapted to be passed through by the inlet sleeve (8) and a second opening adapted to be passed through by the outlet sleeve (9) of the inner bag (2),- an air distributor (21) positioned in the inner bag (2), above the inlet sleeve (8), allowing the incoming polluted gas to be distributed over the cross-section of the inner bag (2). Figure for the abbreviation: Fig. 1,

Description

Title of the invention: FILTER BAG Technical field of the invention

[0001] The present invention relates to a filter bag for the decontamination of a gas, particularly but not exclusively for the decontamination of a gas resulting from the decontamination of soil. Technological background

[0002] Soil remediation consists of making the soil and subsoil of an area suitable for a new use, in particular industrial or residential.

[0003] On-site (in-situ) remediation projects require means to filter pollutants extracted from the soil, which mainly include Volatile Organic Compounds (VOCs).

[0004] These means typically consist of filters filled with a filtering medium, typically activated carbon. The filters, generally made of steel or plastic, are equipped with manholes for filling and emptying. Filling and emptying operations are carried out on site, or upon repatriation of the filters, using lifting equipment and personnel equipped with personal protective equipment (PPE). The filters are generally purchased or leased and then operated on construction sites for periods typically ranging from 1 to 18 months.

[0005] Examples of activated carbon filters are described in particular in documents CN 210905344 and CN 202844823.

[0006] However, activated carbon filters for soil gas purification that are commonly used, particularly those of the preceding documents, have many disadvantages.

[0007] They are heavy, and therefore require handling equipment for their installation and removal, and trucks to transport them from a storage warehouse to the site to be decontaminated.

[0008] The activated carbon itself needs to be transported by truck to be delivered to the site to be decontaminated: supply of new carbon transported in bags and disposal of used carbon in bags.

[0009] Loading new activated carbon into the filter (lifting loads) and emptying used activated carbon require manual handling. These operations pose risks to operators and can sometimes lead to accidents. Furthermore, operators are generally exposed to pollutants and dust, which has a negative impact on their health.

[0010] These risks are aggravated by the fact that current activated carbon filters have a fixed and limited loading capacity, and therefore require activated carbon loading changes, and thus regular manual handling operations. Brief description of the invention

[0011] One object of the invention is to provide a filter bag that overcomes the disadvantages described above.

[0012] The invention aims in particular to provide a filter bag making it possible to do away with the steps of handling bags of filter media, typically activated carbon, loading the filter media into industrial filters, and purging the polluted filter media from these industrial filters at the end of the process.

[0013] In connection with the above, the invention is particularly aimed at reducing the risks due to the handling of the filter medium and the production costs associated with the decontamination of the gas.

[0014] To this end, the invention proposes a filter bag for the decontamination of a polluted gas, mainly characterized in that it comprises: - a sealed inner bag, comprising a lateral surface, a base and a top surface which define an internal space suitable for containing a filter medium, the inner bag further comprising an inlet sleeve for the polluted gas into the inner bag adapted to be connected to a source of polluted gas, and an outlet sleeve for the purified gas out of the filter bag, - an outer casing adapted to receive the inner pouch, which surrounds at least the base and the lateral surface of the inner pouch, the outer casing comprising a first opening adapted to be passed through by the inlet sleeve and a second opening adapted to be passed through by the outlet sleeve of the inner pouch, - an air distributor positioned in the inner bag, above the intake sleeve, allowing the polluted gas entering to be distributed over the section of the inner bag.

[0015] The filter bag according to the invention allows for the conditioning of the filter medium, typically activated carbon, and the decontamination of gases using said filter medium with a single device, thus eliminating the steps of handling bags of filter media, loading the filter media into industrial filters, and purging the contaminated filter media from these industrial filters at the end of the process. The risks associated with handling the filter media and the production costs related to gas decontamination are therefore reduced.

[0016] Indeed, the inner bag contains a charge of filter media, and the inlet sleeve of the inner bag can connect directly to the gas source at The filter bag is ready for use at the remediation site. At the end of the process, the filter bag can be transported to a treatment center where the filter media is disposed of or regenerated, meaning it is rid of pollutants for later reuse. In other words, the filter media arrives at and leaves the treatment site in its filter, i.e., in the filter bag. This eliminates the need for filling and purging the filter media, which is required with a fixed purification system. Remediation costs are also reduced, particularly because remediation companies or industrial operators no longer need to rent filters.

[0017] In practice, the cross-section of the inner bag covered by the air distributor is as large as possible. Preferably, the air distributor extends over the entire cross-section of the inner bag, at the level of a lower part thereof, near its base.

[0018] In other respects, the filter bag according to the invention has the following different characteristics taken alone or in technically possible combinations:

[0019] - the inlet sleeve is arranged on a lower part of the inner bag, and the outlet sleeve is arranged on an upper part of the inner bag, the gas flowing in the filter bag from the lower part to the upper part of the inner bag. In other words, the inlet sleeve is arranged near the base of the inner bag, and the outlet sleeve is arranged near the upper surface of the inner bag; - the filter bag also includes a skirt positioned in the inner bag, in contact with the air distributor, preferably above the air distributor, allowing to improve the seal between the air distributor and the inner bag; - the filter bag is such that: - the lateral surface of the inner pouch includes openings arranged at different heights, - the lateral surface of the outer casing includes openings, arranged at different heights corresponding to the openings of the inner pouch, - the filter bag further includes conduits adapted to be inserted into the openings of the inner bag and the outer envelope, the conduits being adapted to circulate condensate of the purified gas from the interior space of the inner bag to the outside of the filter bag; - The air distributor includes a plate that extends across the entire cross-section of the inner bag, and feet that support the plate. The plate is therefore sen possibly parallel to the base of the inner bag. Preferably, the feet rest on the base of the inner bag, and leave a space between said air distributor and said base which the incoming gas can occupy before passing through the air distributor, which further promotes the distribution of the gas; - the outer casing includes an open upper surface adapted to allow loading of the inner bag and insertion of the air distributor into the inner bag; - the intake sleeve for the polluted gas and / or the exhaust sleeve for the purified gas is flexible; - the outer casing includes carrying handles for transporting the filter bag; - the filter bag also includes a protective support to protect the inner bag and / or outer casing against puncture, adapted to rest against the ground when the filter bag is placed on the ground; - The filter medium includes activated carbon. Preferably, the filter medium consists solely of activated carbon; - the second opening adapted to be passed through by the evacuation sleeve of the inner bag is the upper surface of the outer envelope.

[0020] The invention also relates to a method for decontaminating a polluted gas using a filter bag as described above, mainly characterized in that it comprises the following steps: - connection of the intake manifold to a source of polluted gas, - gas depollution by admitting the polluted gas into the inner bag of the filter bag via the inlet sleeve, passing the polluted gas through the air distributor, circulating the polluted gas from the air distributor to the upper part of the inner bag through the filter medium to purify the gas, - evacuation of purified gas from the filter bag via the evacuation sleeve.

[0021] In other aspects, the process according to the invention has the following different characteristics taken alone or in technically possible combinations:

[0022] - the process further includes, prior to connecting the inlet sleeve to a source of polluted gas, a step of loading the inner bag filled with a filter medium into the outer casing; - the process is a decontamination process for a polluted gas resulting from the decontamination of soil. Description of the figures

[0023] Other advantages and features of the invention will become apparent from the following description, given by way of illustrative and non-limiting example, with reference to to the following attached figures:

[0024] [Fig.1] is a perspective view of the filter bag of the invention according to one embodiment;

[0025] [Fig.2] [Fig.2] is a perspective view of the filter bag of the invention according to a another mode of implementation;

[0026] [Fig.3] is a longitudinal cross-sectional view of the filter bag of [Fig.1];

[0027] [Fig.4] is a longitudinal cross-sectional view of the filter bag of [Fig.2];

[0028] [Fig. 5] is an exploded view of the filter bag of [Fig. 1] which illustrates its different constituent elements;

[0029] [Fig.6] is an exploded view of the filter bag of [Fig.2] which illustrates its different constituent elements;

[0030] [Fig.7] is another exploded view of the filter bag of [Fig.2];

[0031] [Fig.8] is a schematic longitudinal cross-sectional view of the filter bag.

[0032] Detailed description of embodiments of the invention

[0033] The invention relates to a filter bag for the decontamination of a gas. Preferably, the filter bag is used for the decontamination of a gas resulting from soil remediation. The filter bag can also be used in other fields, such as the filtration of paint booth effluents, filtration in petrochemical or pharmaceutical processes, filtration during tank degassing, or filtration in the manufacturing industry.

[0034] In general, the filter bag according to the invention is usable in areas that may require the capture of Non-Methane Volatile Organic Compounds (acronym NMVOCs).

[0035] Two embodiments of the filter bag are shown in Figures 1 to 8. Figures 1, 3, and 5 illustrate a first embodiment in which the filter bag has a cylindrical cross-section, and Figures 2, 4, 6, and 7 illustrate a second embodiment in which the filter bag has a square cross-section. Figure 8 is common to both the first and second embodiments.

[0036] The filter bag 1 mainly comprises an inner sealed bag 2 and an outer envelope 3.

[0037] The outer casing 3 preferably has a cylindrical shape according to the first embodiment or a parallelepiped shape (square or rectangular) according to the second embodiment, which extends along an axis X. The outer casing 3 comprises a lateral surface 11, a base 12, and a top surface 13, which delimit an interior space 14. Preferably, the top surface 13 is open.

[0038] The outer casing 3 preferably includes carrying handles 15, allowing the filter bag to be transported manually or with the aid of a lifting machine. It It is advantageously flexible, meaning it is capable of deforming slightly under mechanical stress. The relative flexibility of the outer casing 3 facilitates the transport of the filter bag 1 by the handles 15, particularly its lifting, by allowing a slight variation in the distance between the handles and providing a tolerance for the lifting machine. The handles 15 themselves are preferably flexible and able to pivot relative to their attachment to the outer casing.

[0039] The inner pouch 2 preferably has a cylindrical shape according to the first embodiment or a parallelepiped shape (square or rectangular) according to the second embodiment, which extends along the X axis, and is housed in the interior space 14 of the outer casing 3. In general, the inner pouch 2 has a shape similar to that of the outer casing 3. It comprises a lateral surface 4, a base 5, and a top surface 6, which define an interior space 7 adapted to contain a filter medium 24.

[0040] Preferably, the filter medium 24 comprises activated carbon.

[0041] The inner bag 2 further comprises an inlet sleeve 8 adapted for connection to a source of contaminated gas and allowing the gas to be decontaminated to enter the inner bag 2. The inlet sleeve 8 is preferably integrated into the inner bag 2, i.e., it is manufactured as a single unit with the inner bag, or is attached to and fixed to it. It is advantageously flexible to facilitate its connection with the source of contaminated gas. A hose clamp 17 may be provided to secure the connection between the inlet sleeve 8 and the source of contaminated gas.

[0042] The inlet sleeve 8 of the inner bag 2 passes through an opening 18 provided at the level of a lower part 27 of the outer envelope, in order to open onto the outside of the filter bag 1.

[0043] The inner bag 2 also includes a purified gas discharge sleeve 9, located at its upper portion 26. Preferably, the discharge sleeve 9 is arranged on the upper surface 6 of the inner bag 2. The discharge sleeve 9 acts as a chimney and allows the purified gas to be discharged to the outside, possibly for recovery. The purified gas, or effluent, is channeled at the outlet, which allows for measurement of the flow rate and / or pollutant concentration of the purified gas. For this purpose, the discharge sleeve 9 can optionally be connected to a gas collector separate from the filter bag.

[0044] The exhaust sleeve 9 is preferably integrated into the inner bag 2, i.e., it is manufactured as a single unit with the inner bag, or is attached to and fixed to the latter. It is advantageously flexible to facilitate its connection with an external device, such as the gas manifold.

[0045] In practice, the inner pouch 2 containing a filter media charge is positioned in the inner space 14 of the outer casing 3 via the upper surface 13 of this last. The inner pouch 2 is then covered by the outer casing 3, except at least at the level of the inlet sleeve 8 and the outlet sleeve 9, which remain in communication with the external environment. Preferably, the upper surface 6 of the inner pouch is free, in that it is not covered by the outer casing 3.

[0046] The inner bag 2 is sealed, in that neither the filter medium nor the gases or liquids present in the inner bag during the purification of the gas to be depolluted can pass through its constitutive wall, except of course via the inlet sleeve 8 for the entry of the gas to be depolluted and the outlet sleeve 9 of the purified gas.

[0047] The filter bag 1 optionally includes a puncture-resistant protective support 16. In one embodiment, the protective support 16 is positioned between the base 5 of the inner bag 2 and the base 12 of the outer casing 3, thus protecting the inner bag 2 from tearing that may be caused by uneven ground, particularly rocks. This embodiment is illustrated in [Fig. 5], where the protective support 16 comprises a plate. In another embodiment, the protective support 16 is positioned under the base 12 of the outer casing 3, and thus rests on the ground and supports the filter bag 1, thereby protecting the base 12 of the outer casing 3 from tearing. This embodiment is illustrated in [Fig. 6], where the protective support 16 comprises a pallet.

[0048] The filter bag may optionally include a plurality of conduits 19 which pass through openings 10 provided in the lateral surface 4 of the inner bag 2 and respective openings 20 provided in the lateral surface 11 of the outer casing 3. The conduits 19 are thus in fluidic communication between the interior space 7 of the inner bag 2 and the exterior of the filter bag 1.

[0049] The conduits 19 allow condensates of purified gas to circulate from the interior space 7 of the inner bag to the exterior of the filter bag 1, for collection and analysis. These samples of treated gas at different locations within the filter media load allow, in particular, monitoring of the saturation of said filter media load, and therefore monitoring of the quantity of filter media consumed.

[0050] The conduits 19 are preferably separate parts from the inner pouch 2 and the outer envelope 3, and are adapted to be assembled or removed from the latter via their openings 10, 20.

[0051] The conduits 19 are advantageously flexible, in order to facilitate their insertion into the openings 10, 20 of the inner bag 2 and the outer envelope 3, and the recovery of purified gas samples.

[0052] As illustrated in Figures 1 and 3, the conduits 19 are arranged at different heights relative to the X-axis. They are preferably arranged in a straight line along an axis parallel to the X-axis. Alternatively, they can be distributed at different heights, at different locations on the circumference of the inner pouch 2 and the outer envelope 3.

[0053] The distribution of the openings 10, 20 on the lateral surfaces 4, 11 of the inner pouch 2 and the outer casing 3 corresponds to the distribution of the conduits 19. The openings 10, 20 are therefore arranged at different heights, relative to the X axis. They are preferably arranged in a straight line along an axis parallel to the X axis. Alternatively, they can be distributed, at different heights, at different locations on the circumference of the inner pouch 2 and the outer casing 3 respectively.

[0054] According to the invention, the filter bag 1 includes an air distributor 21 arranged in the inner bag 2. The air distributor 21 is arranged above the inlet sleeve 8, along the X axis, when the filter bag 1 is in its operating position in which the base 12 of the outer casing 3 faces the ground.

[0055] The air distributor 21 captures the incoming airflow from the intake sleeve 8 and distributes it over the cross-section of the inner bag 2. For this purpose, the air distributor 21 includes orifices 31 through which the polluted gas can flow to reach the filter medium. The cross-section of the inner bag refers to its transverse section, which is perpendicular to the X-axis. The air distributor extends over the cross-section of the inner bag.

[0056] Furthermore, the air distributor 21 is arranged at a distance from the base 5 of the inner pouch 2, so as to provide a space 33 between said air distributor 21 and said base 5 which the incoming gas can occupy before passing through the air distributor. In doing so, the gas passes through the air distributor vertically, that is to say along the X-axis, which improves its distribution over the cross-section of the inner pouch 2. The space 33 can be obtained, for example, by fixing the air distributor against the lateral surface 4 of the inner pouch 2, or, as particularly illustrated in [Fig. 4], by equipping the air distributor with feet 32 ​​on which it rests.

[0057] The air distributor 21 advantageously creates a relative seal between the inner bag 2 of the effluent conduit and said air distributor 21, thus preventing the gas flow entering the inner bag from passing through only a small portion of the filter medium, for example circulating only at the periphery of the inner bag 2 and thus passing through only a peripheral part of the filter medium, resulting in heterogeneity of the consumption of the filter medium and therefore in degraded gas purification.

[0058] The air distributor 21 therefore forces the polluted gas to pass through the filter media charge over its entire cross-section (which corresponds to the cross-section of the inner bag), and thus improves the purification of the gas.

[0059] The air distributor 21 is adapted to support the load of filter media 24 contained in the inner bag 2, and for this purpose has a rigid structure.

[0060] The filter bag 1 optionally includes a skirt 29 positioned in the inner bag 2.

[0061] The skirt 29 improves the seal between the air distributor 21 and the inner bag 2. It is positioned above and in contact with the air distributor 21, and has a central opening 30 so as not to obstruct the orifices of the air distributor.

[0062] The operation of the filter bag 1 will now be described with particular reference to [Fig.8].

[0063] The filter bag 1 is first connected to a source line of polluted gas via the inlet sleeve 8. The optimal seal between the line bringing the polluted gas and the inlet sleeve 8 is preferably achieved by means of a hose clamp 17 which clamps said inlet sleeve 8 without damaging it.

[0064] The incoming polluted gas, symbolized by arrow 22, enters the filter bag 1 via the inlet sleeve 4, then passes through the air distributor 21 which distributes the gas over the entire cross-section of the base of the inner bag 2. The gas rises along the X axis towards the top of the inner bag 2, i.e. from the lower part 25 to the upper part 26 of the inner bag 2, passing through the filter media charge over its entire cross-section, which has the effect of depolluting the gas.

[0065] When the filter bag 1 is equipped with conduits 19, several fractions of the gas being purified are collected at the outlet of the conduits 19 at different heights of the filter bag 1.

[0066] The purified gas, or effluent, is channeled out through the discharge sleeve 9, which advantageously allows for measurement of the flow rate and / or concentration of pollutants in the purified gas. The flow of the purified gas out is illustrated by arrow 23.

[0067] At the end of the operation of the filter media load, the filter bag 1 is disconnected from the source of polluted gas by removing the hose clamp 17 where applicable. The filter media load is then isolated by closing the inlet sleeve 8 and the outlet sleeve 9, for example by making a knot or by means of a suitable closure system, for example a wire, a removable clip, or a plastic hose clamp (preferably of the Rilsan® or Colson® type).

[0068] The filter bag can then be transported to a treatment center where the filter media is disposed of or regenerated. The filter bag is then opened to empty its contents, or incinerated.

Claims

Claims

1. Filter bag (1) for the decontamination of a polluted gas, comprising: - a sealed inner bag (2), comprising a lateral surface (4), a base (5) and an upper surface (6) which delimit an interior space (7) adapted to contain a filter medium (24), the inner bag (2) further comprising an intake sleeve (8) for the polluted gas in the inner bag (2) adapted to be connected to a source of polluted gas, and an evacuation sleeve (9) for the purified gas from the filter bag (1), - an outer casing (3) adapted to receive the inner bag (2), which surrounds at least the base (5) and the lateral surface (4) of the inner bag (2), the outer casing (3) comprising a first opening (18) adapted to be crossed by the intake sleeve (8) and a second opening (13) adapted to be crossed by the evacuation sleeve (9) of the inner bag (2),the filter bag (1) being characterized in that it further comprises an air distributor (21) positioned in the internal bag (2), above the intake sleeve (8), making it possible to distribute the polluted gas entering over the section of the internal bag (2).,

2. The filter bag (1) according to claim 1, wherein the inlet sleeve (8) is arranged on a lower portion (25) of the inner bag (2), and the outlet sleeve (9) is arranged on an upper portion (26) of the inner bag (2), the gas flowing in the filter bag (1) from the lower portion (25) to the upper portion (26) of the inner bag (2).

3. Filter bag (1) according to claim 1 or claim 2, further comprising a skirt (29) positioned in the inner bag (2), in contact with the air distributor (21), making it possible to improve the seal between the air distributor (21) and the inner bag (2).

4. Filter bag (1) according to any one of the preceding claims, wherein: - the lateral surface (4) of the inner bag (2) comprises openings (10), arranged at different heights, - the lateral surface (11) of the outer casing (3) comprises openings (20), arranged at different heights in correspondence with the openings (10) of the inner bag (2), - the filter bag (1) further comprises conduits (19) adapted to be inserted into the openings (10, 20) of the inner bag (2) and the outer casing (3), the conduits (19) being adapted to circulate condensates of the purified gas from the interior space (7) of the inner bag (2) to the outside of the filter bag (1).

5. A filter bag (1) according to any preceding claim, wherein the air distributor (21) comprises a plate which extends over the entire section of the inner bag (2), and feet (32) which support the plate.

6. Filter bag (1) according to any one of the preceding claims, wherein the outer casing (3) comprises an open upper surface (6) adapted to allow loading of the inner bag (2) and insertion of the air distributor (21) into the inner bag (2).

7. Filter bag (1) according to any one of the preceding claims, wherein the inlet sleeve (8) for the polluted gas and / or the outlet sleeve (9) for the purified gas is flexible.

8. A filter bag (1) according to any preceding claim, wherein the outer casing (3) comprises carrying handles (15) for carrying the filter bag (1).

9. A filter bag (1) according to any preceding claim, further comprising a protective support (16) for protecting the inner bag (2) and / or the outer casing (3) against puncture, adapted to rest against the ground when the filter bag (1) is placed on the ground.

10. A filter bag (1) according to any preceding claim, wherein the filter media (24) comprises activated carbon.

11. Method for decontaminating a polluted gas using a filter bag (1) according to any one of claims 1 to 10, characterized in that it comprises the following steps: - connection of the intake sleeve (8) to a source of polluted gas, - decontamination of the gas by admission of the polluted gas into the internal bag (2) of the filter bag (1) via the intake sleeve (8), passage of the polluted gas through the air distributor (21), circulation of the polluted gas from the air distributor to the upper part (26) of the internal bag (2) through the filter medium (24) to purify the gas, - evacuation of the purified gas from the filter bag via the evacuation sleeve (9).

12. A decontamination method according to claim 11, further comprising, prior to connecting the intake sleeve (8) to a source of polluted gas, a step of loading the internal bag (2) filled with a filter medium (24) in the outer casing (3).

13. A decontamination method according to claim 11 or claim 12, which is a method of decontaminating a polluted gas resulting from the decontamination of soil.

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