GB2599415A

GB2599415A - Improvements to filter cartridges

Info

Publication number: GB2599415A
Application number: GB2015532.1A
Authority: GB
Inventors: Baker Troy
Original assignee: Respiratory Tech Ltd
Current assignee: Respiratory Tech Ltd
Priority date: 2020-09-30
Filing date: 2020-09-30
Publication date: 2022-04-06
Also published as: GB202015532D0

Abstract

A filter cartridge 14’ for a respirator, the cartridge comprising a housing 16 – preferably a clamshell housing - have a base 20 and a cover 18 forming a cavity therebetween, the cavity defining an air inlet 70 and outlet 72 and being capable of receiving a filter disposed between the inlet and outlet. The inlet is closable to undertake fit testing, the inlet being closable by means of a movably mounted inlet closure member 100, the inlet closure member being movably mounted on one end of the housing and is closable by displacement substantially in a direction toward the opposite end of the housing. The inlet closure member is preferably a flap hingedly connected to the housing, preferably mounted to an end wall 30, of the cover of the housing. The filter cartridge may be mounted to a respiratory mask (12, Fig 1) and may be provided in a kit comprising a plurality of filters 60.

Description

IMPROVEMENTS TO FILTER CARTRIDGES

The present invention relates to respiratory protection devices and filter cartridges for such respiratory protection devices.

Respiratory protection devices or respirators filter the air that is supplied to a user from environmental contaminants. Such contaminants might be in the form of particles such as dust or viruses, bacteria and other potentially harmful particles.

Respirators tend to be formed of a tight-fitting sealing portion in the form of a mask that adopts its profile to a user's face through means of a soft pliable material such as TPU/rubber or silicone then a filter or set of filters that prevent the harmful element getting to the user.

The filter is typically made of pleated paper and often located within a clamshell housing which attaches to the mask of the respirator. The filter material is located between the external environment and the user's airways along an airflow path and is intended to remove harmful particulates from the air delivered to a user's airways.

On a daily basis, a user of a respirator should perform a negative fit check. Such as check involves blocking the airflow to the interior of a mask and inhaling. If the seal is good, the mask will pull into the user's face and should remain in situ until a user unblocks the airflow. If the user sees the mask begin to return to its original position over a 10 second period then there is not a good seal between a user's face and the mask. In such a situation the mask is to be removed and refitted to ensure a satisfactory seal between mask and user's face.

In practice the airflow is blocked by a user covering the air inlet with their hands. A problem associated with using hands to cover the air inlet is that a user must orientate their digits or palm of hand to correctly cover the air inlet. Additionally, the air inlet might comprise a plurality of apertures which can be difficult for certain hand sizes to correctly cover and effectively close to the extent that air may leak through and give a user the false impression that the mask is not properly situated.

GB2526390 discloses a filter cartridge having an inner receptacle and an outer cover pivotally mounted to the inner receptacle by means of a fixed pivot at a longitudinal end of the cartridge. To perform a negative fit check, a user pinches the filter cartridge to bring the cover into contact with the inner receptacle. This action, however, levers the cartridge away from the mask which deforms the mask and permits the ingress of air and may incorrectly give rise to a negative fit failure for a mask that adequately fits a user and was correctly worn prior to performing the check.

It would be advantageous to alleviate or overcome one or more of the problems associated with the prior art.

In accordance with a first aspect of the present invention, there is provided a filter cartridge for a respirator comprising a housing having a base and a cover forming a cavity therebetween, said cavity having an inlet and an outlet in fluid communication with one another such that fluid may pass therethrough, said cavity capable of receiving a filter disposed between said inlet and outlet, wherein said inlet is closable by means of a moveably mounted inlet closure member capable of moving between a first configuration in which the inlet is open and fluid may enter therethrough and a second configuration wherein the inlet is closed and fluid may not enter therethrough, wherein the inlet closure member is moveably mounted on one end of the housing and is closable by displacement substantially in a direction towards the opposite end of the housing.

The present invention thus prevents a user from performing a negative fit check that levers the cartridge away from a mask to which it can be mounted and thus prevents deformation of the mask and an incorrect negative fit failure.

The inlet closure member may be hingedly mounted to the housing. In an embodiment, the inlet closure member is hingedly mounted to the cover of the housing.

The outlet may be disposed in the base of the housing in an embodiment or the inlet may be disposed in the base of the housing.

In an embodiment, the housing may be substantially cuboidal, particularly rectangular cuboidal in shape.

The inlet closure member may comprise at least a portion of an end wall of the housing.

In an embodiment, the outlet may comprise one member of a mating pair for mating with and securing the filter cartridge to a mask. Advantageously, the outlet may comprise a male member of a mating pair for securing the filter cartridge to a mask.

In an embodiment, the cartridge may comprise a biassing member to bias the closure member in an open configuration to permit the flow of fluid therethrough.

A suitable filter for use in the present invention may comprises a pleated matrix. In an embodiment, the filter comprises a pleated cellulosic material.

Advantageously, there may be provided a baffle associated with the inlet to exclude larger contaminants to prevent entry into the cavity of the housing.

In an embodiment, the cover and base members of the housing may be substantially rigid members of the cartridge. Advantageously, the base and cover of the housing are fixedly connected to one another to prevent the housing from disassembling accidentally.

In an embodiment, the only moveable member of the cartridge is the moveably mounted inlet closure member, mounted on the cover of the housing or the base of the housing.

In accordance with a further aspect of the present invention, there is provided a respiratory protection device comprising a mask to fit a user's face respiratory airways and a filter cartridge as described hereinabove.

The present invention will now be described, by way of example only, with reference to the following drawings, in which: Fig. 1 a and b show a respiratory protection device in accordance with the present invention; Fig. 2 shows an exploded view of a cartridge in accordance with the present invention; Fig. 3 shows the base of a housing in accordance with the present invention; Fig. 4 a and b are cross sectional views of a cartridge in accordance with the present invention; and Fig. S a and b show a respirator in accordance with the present invention being subjected to a negative fit check.

Fig. 1 a and b show a respirator 10 consisting of a mask 12 ergonomically shaped to fit a user's face to which are releasably mounted two filter cartridges 14', 14".

Fig. 2 shows one filter cartridge 14' in exploded view. The cartridge has a clamshell housing 16 comprising upper cover 18 overlying a lower base member 20.

The cover 18 has a substantially rectangular face 22 having two side walls 24,26 and a first and second end walls 28, 30, each depending downwardly and extending substantially perpendicularly to the general plane of the face 22 to form a cover.

The base member 20 (see Fig. 2 and 3) has a substantially rectangular body 40 having a rectangular base 42 and upwardly depending side walls 46,46' and first end wall 48, each extending substantially perpendicularly from the base 42 with second end wall 50 extending at an incline form base 42 to form an open substantially rectangular box having a recess 44 which is shaped to receive a complementarily shaped cuboidal pleated paper filter 60. The filter 60 is secured in the recess 44 by a bead of adhesive around the four quadrants to hold it in place. Substantially planar and rectangular seal 62 sits on top of the perimetral upper edge 64 of the side walls and end walls 46, 46, 48, SO of the base member 20 and co-operates with the underside of the cover member 14' to prevent air from entering the cartridge via the side walls.

At the second end 50 of base member 20 is located an air inlet 70 and located proximal to the first end 48 in the rectangular base 42 is an air outlet 72 in fluid communication with the inlet 70 such that air may pass from the inlet through the cartridge body and out of the outlet 72.

S

The outlet 72 is a circular aperture in the rectangular base 42 and has a male member 90 of a mating pair to releasably secure the cartridge to a complementarily shaped female mating member 92 disposed on the mask 12.

The mating members may in an embodiment comprise bayonet attachment or a complementarily shaped threaded shaft and hole.

Located at the second end 30 of the cover 18 proximal to the air inlet 70 is a hinged substantially planar rectangular flap 100 moveable between a first configuration in which the flap is flush with the face of the second end of the cover and the air inlet is therefore open to permit the flow of air therethrough and a second configuration in which the flap 100 is moved to pivot about its hinge 102 to close the air inlet to prevent the flow of air therethrough.

The free end 104 of the flap has a perpendicularly extending wall 106 that extends outwardly and provides a grip for a user to engage with to actuate the flap 100. Adjacent to the wall 106 but extending inwardly, perpendicular to the plane of the flap 100 is a lip 108 that co-operates with and overlies an inclined wall 110 having apertures therethrough to permit the flow of air. The lip 106 ensures an airtight seal when the flap is closed to prevent airflow through the inlet 70.

Located downstream of the inlet is a baffle 120 which assists in retaining the filter 60 and prevent in the ingress of larger particles or material into the interior of the cartridge.

The flap 100 is biased into its first configuration such that the air inlet is open by means of a live hinge in the material from which the cover, hinge and flap are made such that a user must overcome the bias to close the air inlet. On the downstream side of the flap 100 is located a seal 108 made from a resiliently deformable material, such as foam, such that when compressed to close the air inlet and seal to prevent air ingress into the cavity, the flap wants to adopt its open configuration when a closing force is removed.

Associated with the air outlet 72 is an optional one way valve 80 to prevent exhaled air going out through the filter and inlet 70 but allows a user to breath in through it. In such an embodiment, there would be an exhale valve in the mask. In an embodiment there may not be an exhale valve in the mask and the user will breath in and out through the filter.

Fig. 4 a and b show the cartridge in its open and closed configurations respectively. The arrows in Fig. 4a illustrate the flow path of air through the inlet across the filter and through the outlet. The flap is in its closed configuration in Fig. 4b such that no air may enter the cartridge through the air inlet.

In use (see Fig. 5 a and b) the cartridge is orientated on the mask in such a fashion that a user is able to grip the cartridge either side of the mask and use its fingers to engage with and actuate the flap, by depressing the flap so that the bias is overcome and the flap pivots about its hinge to move into its closed configuration obstructing the air inlet.

Since the direction of the force applied is generally in a direction parallel to the longitudinal axis of the cartridge as shown by the arrows in Fig. 5 b, a user is not pressing the underside base and top cover and thus not pulling the filter away from the mask and potentially breaking the seal that the mask makes with a user's face.

Claims

CLAIMS1. A filter cartridge for a respirator comprising a housing having a base and a cover forming a cavity therebetween, said cavity having an inlet and an outlet in fluid communication with one another such that fluid may pass therethrough, said cavity capable of receiving a filter disposed between said inlet and outlet, wherein said inlet is closable by means of a moveably mounted inlet closure member capable of moving between a first configuration in which the inlet is open and fluid may enter therethrough and a second configuration wherein the inlet is closed and fluid may not enter therethrough, wherein the inlet closure member is moveably mounted on one end of the housing and is closable by displacement substantially in a direction towards the opposite end of the housing. 2. 3. 4. 5. 6.
A filter cartridge as claimed in claim 1 wherein the inlet closure member is hingedly mounted to the housing.
A filter cartridge as claimed in claim 2 wherein the inlet closure member is hingedly mounted to the cover of the housing.
A filter cartridge as claimed in any of the previous claims wherein the outlet is disposed in the base of the housing.
A filter cartridge as claimed in any previous claim wherein the inlet is disposed in the base of the housing.
A filter cartridge as claimed in any previous claim wherein the housing is substantially rectangular in shape.
7. A filter cartridge as claimed in claim 6 wherein the inlet closure member comprises at least apportion of an end wall of the housing.
8. A filter cartridge as claimed in any previous claim wherein the outlet comprises one member of a mating pair for mating with and securing the filter cartridge to a mask.
9. A filter cartridge as claimed in claim 8 wherein the outlet comprises a male member of a mating pair for securing the filter cartridge to a mask.
10. A filter cartridge as claimed in any previous claim having a biassing member to bias the closure member in an open configuration to permit the flow of fluid therethrough.
11. A filter cartridge as claimed in any one of the previous claims wherein the filter comprises a pleated matrix.
12. A filter cartridge as claimed in claim 11 wherein the filter comprises pleated cellulosic material.
13. A filter cartridge as claimed in any previous claim further comprising a baffle associated with the inlet to exclude larger contaminants to prevent entry into the cavity of the housing.
14. A filter cartridge as claimed in any previous claim wherein the cover and base members of the housing are substantially rigid.
15. A filter cartridge as claimed in any previous claim wherein the base and cover of the housing are fixedly connected to one another.
16. A filter cartridge as claimed in any one of the previous claims wherein the only moveable member of the cartridge is the moveably mounted inlet closure member, mounted on the cover of the housing.
17. A filter cartridge as claimed in any one of the previous claims wherein the only moveable member of the cartridge is the moveably mounted inlet closure member, mounted on the base of the housing.
18. A filter cartridge as claimed in any one of the previous claims wherein the cover overlies the base of the housing.
19. A respiratory protection device comprising a mask to fit at least a portion of a user's respiratory airways and a filter cartridge as described hereinabove.
20. A kit of parts comprising a respiratory protection device and/or filter cartridge as claimed in any previous claims and a plurality of filters.