GB2547256A

GB2547256A - Waterproof respirator filter

Info

Publication number: GB2547256A
Application number: GB1602560.3A
Authority: GB
Inventors: Langford Graham
Original assignee: Scott Health and Safety Ltd
Current assignee: Scott Health and Safety Ltd
Priority date: 2016-02-12
Filing date: 2016-02-12
Publication date: 2017-08-16
Also published as: GB201602560D0

Abstract

A respirator assembly comprises a respirator having a filter unit attachment port (21 Figure 2). A filter unit 1 is attachable to the filter unit attachment port 21. The filter unit 1 comprises a housing 2 having an air inlet 3, an air outlet 4, and filter material 6 disposed between the air inlet 3 and air outlet 4. A first layer of breathable waterproof material 7 is provided between the inlet 3 and the filter material 6 to prevent moisture at the inlet 3 from reaching the filter material 6 whilst allowing air to pass therethrough. A second layer of breathable waterproof material 8 is associated with the outlet 4 of the housing 2 and is located downstream of the filter material 6. The breathable waterproof layers may be made from polytetrafluoroethylene (PTFE). A filter assembly with the second waterproof layer 8 located within the filter unit 1 and a respirator having a breathable waterproof layer 8 proximate the filter attachment port 21 are also claimed.

Description

Waterproof Respirator Filter

The present invention relates to improvements in relation to the protection of filter material used in APR respirators from the ingress of water or moisture.

Respirators which are generally used in a wide range of applications typically contain activated carbon and particulate media which acts to absorbed or prevent passage of harmful particles entrained in the air entering the filter so as to deliver clean, safe air to the wearer. It is, however, important that the filter material (both the activated carbon and the particulate media) is kept away from water / moisture, since some particulate media which is used, such as glass fibre, will tend to soak up water which then inhibits the passage of air through the media, making breathing for the wearer more difficult. Furthermore, activated carbon will also tend to soak up water, which causes lowering of its efficiency to remove chemical vapours from the atmosphere, and therefore compromises the effectiveness of the carbon in protecting the user.

In order to protect the filter material from moisture in the air of the surrounding atmosphere which is drawn through the filter during normal use, it is known to provide a layer of waterproof particulate material, such as PTFE, in the filter between the filter inlet and the activated carbon / particulate material. The waterproof particulate material provides a layer of low breathing resistance material which allows air to pass through without offering any significant resistance to the flow, but prevents the passage of water, thereby protecting the filter material from water ingress through the filter inlet.

However, this layer of material on the inlet of the filter only protects against moisture ingress through the inlet and users must still protect their respirators and filters from general water ingress both when being carried and also when being worn. In particular, when the filter is being carried in pack or the like, water can enter the filter through the air outlet if, for example, the pack becomes submerged or damp, resulting in the operation of the filter being compromised and necessitating replacement. Equally, if water enters the mask itself, this may leak back through the mask and into the filter through the filter air outlet, again compromising the effectiveness of the filter. Users are therefore recommended to avoid water, or to use a watertight carrier for the mask and filter, which can be very expensive.

According to the present invention there is provided a filter assembly comprising a housing having an air inlet, an air outlet, and filter material disposed between the air inlet and air outlet which, in use, operates to remove harmful particles from air passing from the inlet to the outlet, a first layer of breathable waterproof material being provided between the inlet and the filter material to prevent moisture at the inlet from reaching the filter material whilst allowing air to pass therethrough, and further comprising a second layer of breathable waterproof material associated with the outlet of the housing and located downstream of the filter material, said second layer of breathable waterproof material protecting the filter material from the ingress of water from the outlet side of the housing. A filter assembly in accordance with the invention has the advantage that the filter material is effectively protected from water at both the inlet and the outlet side in a manner which does not require expensive watertight carriers.

Preferably the filter material comprises at least one of a particulate media, in particular glass fibre, and activated carbon.

At least the second layer of breathable waterproof material is preferably a PTFE waterproof membrane material, which is preferably sealed in place to prevent the passage of moisture around said layer.

In one embodiment, the second layer of breathable waterproof material is located within the housing between the filter material and the outlet so as to protect the filter material within the filter assembly as a stand alone unit. This has the advantage that even when the filter assembly is detached from the breathing mask, the filter material is still effectively protected. In this embodiment, the filter material is then sandwiched between first and second layers of breathable waterproof material.

In an alternative embodiment, the second layer of breathable material is provided in a filter assembly attachment port of a breathing mask adjacent to the port so as to prevent moist from passing out of the breathing mask port rather than from entering the outlet port of the filter assembly.

The present invention further therefore provides a respirator having a filter unit attachment port to which, in use, is attached a filter unit operable to filter contaminants from gas which enters the respirator through the attachment port, a layer of breathable waterproof material being provided in the respirator proximate the filter unit attachment port which operates to prevent moisture from passing from inside the respirator out of the filter unit attachment port.

Preferably, the layer of breathable waterproof material is a PTFE waterproof membrane material, which is preferably sealed in place to prevent the passage of moisture around said layer. IN one embodiment, the layer of breathable waterproof material is mounted in a respirator inhalation filter attachment which acts as an adaptor between the respirator and as filter unit.

The present invention still further provides a respirator assembly comprising a respirator having a filter unit attachment port, a filter unit attachable to the filter unit attachment port and operable to filter contaminants from gas which enters the respirator through the attachment port, the filter unit comprising a housing having an air inlet, an air outlet, and filter material disposed between the air inlet and air outlet which, in use, operates to remove harmful particles from air passing from the inlet to the outlet, a first layer of breathable waterproof material provided between the inlet and the filter material to prevent moisture at the inlet from reaching the filter material whilst allowing air to pass therethrough, and a second layer of breathable waterproof material associated with the outlet of the housing and located downstream of the filter material, said second layer of breathable waterproof material protecting the filter material from the ingress of water from the outlet side of the housing.

Preferably, at least the second layer of breathable waterproof material is a PTFE waterproof membrane material, which is preferably sealed in place to prevent the passage of moisture around said layer.

In one embodiment, the second layer of breathable waterproof material is mounted in the filter unit between the filter material and the outlet port. Alternatively, the second layer of breathable waterproof material may be located in the filter unit attachment port of the respirator.

In order that the invention may be well understood, there will now be described some embodiments thereof, given by way of example, reference being made to the accompanying drawings, in which:

Figure 1 a partially cut away view of a filter unit according to a first embodiment of the invention; and

Figure 2 is a sectional view of an inhalation assembly of a respirator modified in accordance with a second embodiment of the invention.

Referring first to Figure 1, there is shown a filter unit 1 of the type which is removably attachable to a respirator in a manner which is well known in the art. The unit 1 is formed of a canister housing 2 which has an air inlet opening 3 at one end and an air outlet opening 4 at the other end. The air outlet opening 4 is formed with a thread on its outer surface for removably attaching the housing to a respirator port in a manner well known in the art. A filter cavity 5 is formed in the canister housing 2, which is in fluid communication with both the inlet 3 and outlet 4 openings such that air entering the housing 2 through the inlet 3 passes through the cavity 5 and out through the outlet opening 4. Filter material 6 of the type which is well known in the art is disposed in the filter cavity and operates to filter unwanted species from air passing between the inlet and outlet openings. In particular, the filter material 6 may comprise activated carbon and particulate media such as glass fibre, but other filter material may also be used within the scope of the invention.

In order to protect the filter material 6 from compromise from the ingress of moisture through the inlet opening 3, a layer of breathable waterproof particulate material 7 is also provided in the cavity 5 between the inlet opening 3 and the filter material 6. Preferably the waterproof particulate material is PTFE but other materials are also possible. The layer of breathable waterproof particulate material 7 is mounted in the cavity so as to be sealed to the inside of the canister housing 2 such that all air entering the filter unit 1 through the inlet opening 3 passes through the breathable waterproof particulate material 7. This material 7 operates to allow air to pass therethrough with low resistance, but prevents the passage of water molecules, such that it protects the filter material 6 from the ingress of water through the inlet 3.

In accordance with the present invention, a second layer of breathable waterproof particulate material 8 is provided on the outlet side 4 of the filter material 6, so as to prevent contamination of the filter material by moisture entering through the outlet opening. In this embodiment, this second layer of breathable waterproof particulate material 8 is also mounted within the canister housing 2 and is located between the filter material 6 and the outlet opening 4, being in sealed relationship with the inner surface of the canister housing 2 so as to prevent moisture passing around the second layer 8 and reaching the filter material. The material of the second layer of breathable waterproof particulate material 8 is preferably PTFE but other materials which prevent the ingress of water whilst affording a low breathing resistance are also possible.

In the illustrated embodiment, the filter material is shown sandwiched between the two layers of breathable waterproof particulate material, but it will be understood that the layers of breathable waterproof particulate material may be spaced apart from the filter material without departing from the invention.

According to a second embodiment of the invention, instead of the second layer of breathable waterproof particulate material being disposed in the canister housing 2, it may instead be located proximate a filter canister attachment port provided on a respirator mask for attaching a filter unit 1 of the type illustrated in Figure 1 to the respirator mask.

Figure 2 shows an inhalation assembly 20 of a respirator of a type which is known in the art. The inhalation assembly 20 has an inlet end which is formed as a threaded inlet port 21 by means of which a filter unit may be screwingly attached to the assembly 20 for filtering air drawn into the respirator through the assembly. As is well known in the art, a control valve 22 is provided in the assembly 20 for controlling the flow of air through the assembly 20 A membrane of breathable waterproof material 23 is mounted in the inhalation assembly adjacent the inlet port 21 such that any fluid travelling from the respirator towards the inlet port 21 passes through the membrane 23. The membrane 23 is sealed in place by means of a suitable seal 24, such as a rubber gasket, which prevents any material such as water, particles or chemicals from passing between the edge of the membrane 23 and the inhalation assembly.

The membrane 23 thereby prevents moisture from passing out of the inlet port and thereby prevents the filter material housed within a filter unit attached to the inlet port from being contaminated by water from the outlet side of the filter unit.

It will be further recognised that it is within the scope of the invention to provide a layer of breathable waterproof material both within the filter unit on the outlet side of the filter material as well as in the respirator by combining the configurations shown in Figures 1 and 2.

Claims

1. A filter assembly comprising a housing having an air inlet, an air outlet, and filter material disposed between the air inlet and air outlet which, in use, operates to remove harmful particles from air passing from the inlet to the outlet, a first layer of breathable waterproof material being provided between the inlet and the filter material to prevent moisture at the inlet from reaching the filter material whilst allowing air to pass therethrough, and further comprising a second layer of breathable waterproof material associated with the outlet of the housing and located downstream of the filter material, said second layer of breathable waterproof material protecting the filter material from the ingress of water from the outlet side of the housing.

2. A filter assembly according to claim 1, wherein at least the second layer of breathable waterproof material is a PTFE waterproof material.

3. A filter assembly according to claim 1 or claim 2, wherein the second layer of breathable waterproof material is preferably sealed in place to prevent the passage of moisture around the edge of said layer.

4. A filter assembly according to any of the preceding claims, wherein the second layer of breathable waterproof material is located within the housing between the filter material and the outlet so as to protect the filter material within the filter assembly as a stand alone unit.

5. A filter assembly according to claim 4, wherein the filter material is then sandwiched between first and second layers of breathable waterproof material.

6. A filter assembly according to any of claims 1 to 3, wherein the second layer of breathable material is provided in a filter assembly attachment port of a respirator to which the filter assembly is attached.

7. A respirator having a filter unit attachment port to which, in use, is attached a filter unit operable to filter contaminants from gas which enters the respirator through the attachment port, a layer of breathable waterproof material being provided in the respirator proximate the filter unit attachment port which operates to prevent moisture from passing from inside the respirator out of the filter unit attachment port.

8. A respirator according to claim 7, wherein the layer of breathable waterproof material is a PTFE waterproof material.

9. A respirator according to claim 8, wherein the layer of breathable waterproof material is a PTFE waterproof membrane.

10. A respirator according to any of claims 7 to 9, wherein the layer of breathable waterproof material sealed in place to prevent the passage of moisture around said layer.

11. A respirator assembly comprising a respirator having a filter unit attachment port, a filter unit attachable to the filter unit attachment port and operable to filter contaminants from gas which enters the respirator through the attachment port, the filter unit comprising a housing having an air inlet, an air outlet, and filter material disposed between the air inlet and air outlet which, in use, operates to remove harmful particles from air passing from the inlet to the outlet, a first layer of breathable waterproof material provided between the inlet and the filter material to prevent moisture at the inlet from reaching the filter material whilst allowing air to pass therethrough, and a second layer of breathable waterproof material associated with the outlet of the housing and located downstream of the filter material, said second layer of breathable waterproof material protecting the filter material from the ingress of water from the outlet side of the housing.

12. A respirator assembly according to claim 11, wherein at least the second layer of breathable waterproof material is a PTFE waterproof material.

13. A respirator assembly according to claim 11 or claim 12, wherein the second layer of breathable waterproof material is mounted in the filter unit between the filter material and the outlet port.

14. A respirator assembly according to claim 11 or claim 12, wherein the second layer of breathable waterproof material is located in the filter unit attachment port of the respirator.

15. A filter assembly substantially as herein described with reference to the accompanying drawings.

16. A respirator substantially as herein described with reference to the accompanying drawings.

17. A respirator assembly substantially as herein described with reference to the accompanying drawings.