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EP-4739400-A1 - FILTERING UNIT WITH ADSORBENT BED WITH DIFFERENTIATED THICKNESS

EP4739400A1EP 4739400 A1EP4739400 A1EP 4739400A1EP-4739400-A1

Abstract

A filtering unit (1), for gases and particulates, comprises a casing (2) within which a bed of adsorbent material (43) is placed and on which a particulate filter element (30) is placed, on the latter a cover (32) being arranged which is integral with the casing and encloses such particulate filter element (30). The bed made of an adsorbent material (43) has portions with differentiated thickness (49, 50) within the casing.

Inventors

  • KALENSKY, Ondrej
  • HARTROPP, BEN
  • CALLAND, ANDREW

Assignees

  • GVS Filter Technology Uk Ltd

Dates

Publication Date
20260513
Application Date
20240617

Claims (13)

  1. 1. A filtering unit for gases and particulates usable in a respiratory protective device, said filtering unit (1) comprising a casing (2) having an inner cavity (6) containing a bed of adsorbent material (43) , a particulate filter (30) being externally associated with said casing (2) and inserted into a cover (32) of the filtering unit integral with said casing (2) , said cover being provided with at least one through opening (33) , the casing comprising two concave parts (3, 4) , connected to each other and delimiting the inner cavity (6) containing said bed of filtering material (43) , a first part (3) of the casing presenting a through hole (13) adapted to cooperate with a valve member (16) , the second part also having at least one through opening (19) at which the particulate filter (30) is placed, characterized in that the bed of adsorbent material has a differentiated thickness or volume, i.e. it is graduated inside different portions (36, 38) of the cavity (6) of said casing.
  2. 2. The filtering unit according to claim 1, characterized in that the thickness or volume of the bed of adsorbent material (43) is greater in a portion (38) of the cavity (6) of said casing where there is the greatest air flow between said hole (13) and said opening (19) of the parts (3, 4) of the casing.
  3. 3. The filtering unit according to claim 1, characterized in that a part (3) between said parts (3, 4) of the casing (2) comprises a compartment (11) of variable depth between a lower depth at an edge portion (36) and a greater depth at an internal portion (38) where there is a greater air flow between said hole (13) of the first part (3) of the casing and said at least one opening of the second part (4) of the casing, said compartment (11) being adapted to contain the bed of adsorbent material.
  4. 4. The filtering unit according to claim 3, characterized in that said part comprising the compartment (11) is the first part (3) of the casing (2) , the through hole (13) cooperating with the valve member (16) opening in said internal portion (38) of greater depth.
  5. 5. The filtering unit according to claim 3, characterized in that said compartment (11) is delimited by a transversal face (9) and by a wall (10) rising from an edge of said transversal face (9) , said wall (10) being adapted to cooperate with a wall (23) of the second part (4) of the casing protruding from a transverse face (18) of the latter, said transversal face (9) of said first part (3) of the casing having the through hole (13) and said transversal face (18) of said second part (4) having the at least one opening (19) of the latter.
  6. 6. The filtering unit according to claim 1, characterized in that the thickness or volume of the bed of adsorbent material (43) is measured along a longitudinal axis (W) of the hole (13) of the first casing part (3) or is measured parallel to that axis (W) on a plane containing said longitudinal axis.
  7. 7. The filtering unit according to claim 5, characterized in that at least the transversal face (9) of the first part (3) of the casing has a curved shape on two planes containing orthogonal axes (X, Y) .
  8. 8. The filtering unit according to claim 7, characterized in that it has an overall curved shape with respect to two orthogonal axes (X, Y) .
  9. 9. The filtering unit according to claim 1, characterized in that the bed of adsorbent material comprises at least one of activated carbon, zeolite, alumina, silica, a catalyst, or a combination thereof.
  10. 10. The filtering unit according to claim 1, characterized in that said bed of adsorbent material is contained between two sheets (40, 45) of non-woven fabric which are internally integral with said parts (3, 4) of the casing (1) , said constraint between said sheets and said parts being obtained preferably by hot welding, between each sheet (40, 45) and the corresponding part (3, 4) an empty space (11W) being provided.
  11. 11. The filtering unit according to claim 1, characterized in that said parts (3, 4) of the casing are fixed to each other preferably by ultrasonic welding.
  12. 12. The unit according to claim 1, characterized in that said bed of adsorbent material is compressed in the cavity (6) of the casing (2) .
  13. 13. A user's respiratory protective device such as a face mask or half-face mask or respirator, said device comprising a part covering at least the user's mouth and nose or optionally the user' s eyes and entire face, characterized in that said device comprises a filtering unit (1) according to the preceding claims.

Description

FILTERING UNIT WITH ADSORBENT BED WITH DIFFERENTIATED THICKNESS The present invention relates to a filtering unit according to the preamble of the main claim . Various embodiments of filtering units are known, for example for full-face masks , half-face masks or other respiratory protective devices which are adapted to filter the inhaled air of a user wearing such a device . In particular, the present invention relates to a gas and particulate filtering unit comprising a casing containing a bed of adsorbent material, a particulate filter, for example a pleated one, being arranged on said casing and externally thereto . The bed made of an adsorbent material is generally obtained by using at least one of an activated carbon, alumina, zeolite, silica, a catalyst ( such as goldbased catalyst capable of removing CO) or combinations thereof . In order to contain this "adsorbent bed" , the casing comprises two parts or shells defining a cavity inside the casing . Openings are provided in said parts for the passage of air through the casing . The adsorbent bed is introduced into the cavity, usually in granular form, for example by means of an angled hopper which is made to vibrate and from which the granules pass into the cavity or by means of the " snowstorm" technique . In the cavity, the granules are compacted so as to perform their function of filtering the air which crosses them and passes through the openings of the two parts or shells of the casing . The air comes to the aforesaid casing through the external, pleated filter and from openings provided within a cover of the aforesaid casing . In known solutions , the casing may take various shapes , often cylindrical or rectangular to suit the product form of the manufacturer and the connections to the respirator comprising said filtering unit . Furthermore, the cavity containing the adsorbent bed has a constant depth . US2013/ 0298775 relates to a replaceable filter canister used with purifying respirators . In particular, this prior document relates to a replaceable filter canister shaped to conform to the face of a user . This known kind of filter canister may be considered as conformal filter canister, which is different to the traditional flat outlet wall canister . Since some purchasers of respirators prefer the conformal filter canister while other purchasers prefer the traditional canisters , the suppliers have to make and inventory both types of canister . The solution that the US patent application offers is a single filter assembly which may provide both planar and conformal filter canister functionality . This is obtained by coupling in a removable way a conformal filter canister with a connector piece which connects the canister to the respirator . US2013/ 0298775 describes that the conformal filter has a body having an input end with a convex inlet wall and an output end with a concave outlet wall . These walls are in parallel, spaced-apart relationship joined by a peripheral outside wall to define an enclosed filter chamber in which filter elements (a particulate filter element and an adsorption filter bed) are retained . Both the description and the drawings only describe that the filter chamber is defined by parallel input and output walls and the outside wall, and the drawings clearly only describe that the filter chamber has a continuous thickness or volume : the prior US document does not disclose or suggest that the thickness of the filter chamber changes (i . e . , it is not differentiated or graduated) in different portions of it : the thickness of the filter chamber is the same in any portion of said filter chamber, both where there is the greatest air flow between the inlet and outlet ends and in chamber portions which are on the side of the portion . The prior document does not give any hint to the skilled person to have a filter chamber where the absorption filter bed has a graduated thickness i . e . different thicknesses in different portions of said filter chamber . These known solutions therefore have a relatively high quantity of adsorbent material defining the corresponding adsorbent bed in order to have a suitable filtering capacity . This leads to relatively large filtering unit s with a consequent increase in weight and a reduction in the comfort of use of the respirator by a user . The object of the present invention is to provide a filtering unit with a bed made of an adsorbent material which is improved with respect to known solutions . In particular, the object of the present invention is to provide a filtering unit of the aforementioned type containing a volume of said adsorbent material which allows to optimize the filtering capacity of the unit ; all this without however increasing the overall dimensions of the filtering unit . Another object is to provide a filtering unit of the cited type the production of which involves a reduced use of plastic material . A further object is to provide a filtering unit which o