GB2602137A

GB2602137A - Face mask

Info

Publication number: GB2602137A
Application number: GB2020205.7A
Authority: GB
Inventors: Maddison Fox Stewart; Peter Wilsher Simon; David Cauwood Peter; Georg Laitenberger Peter
Original assignee: Rhipsalis Ltd
Current assignee: Rhipsalis Ltd
Priority date: 2020-12-18
Filing date: 2020-12-18
Publication date: 2022-06-22
Also published as: GB202020205D0

Abstract

A face mask 1 for filtering airborne particles, gases and/or microorganisms comprises (i) a cover 2 for positioning over the mouth and nose of a wearer, (ii) one or more filters 6a,6b for filtering airborne particles, gases and/or micro-organisms (e.g. an FFP1 filter), and (iii) one or more inlet ports 7a,7b for allowing air to enter the mask; wherein the size of the one or more inlet ports is adjustable, e.g. in cross-sectional area through insertion or removal of a removable insert 10a,10b . A kit comprising the face mask and a plurality of inserts for adjusting the cross-sectional area of the one or more ports is also provided.

Description

FACE MASK

The present invention relates to a face mask, in particular to a face mask which provides improved levels of comfort.

Face masks, and in particular respirators, are used to prevent particulates, odours and micro-organisms entering the wearer's airway and hence provide protection for the wearer against infection by airborne bacteria and viruses.

Face masks are an important item of personal protective equipment (PPE) in a variety of settings. For example, in hospitals and care homes where controlling the spread of disease is particularly important, the use of face masks can help to protect not only the wearer but also those individuals with whom the wearer comes into contact.

Respirators and face masks have been used for many decades, as a way of protecting wearers and third parties from the inhalation of hazardous particles, gases and organisms. With the exception of PAPRs (Powered Air Purifying Respirators), the wearer of the device is known to suffer from heat, sweating, discomfort and mild feelings of suffocation and these problems are exacerbated when the mask is worn in a hot, humid environment.

PAPRs provide a continuous flow of filtered air to the wearer but require a fan and power supply, so are more expensive and cumbersome than an unpowered respirator.

It is, therefore, an object of the present invention to seek to alleviate the above identified problems.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, there is provided a face mask for filtering airborne particles, gases and/or micro-organisms, the face mask comprising:- (i) a cover for positioning over the mouth and nose of a wearer, (ii) one or more filters for filtering airborne particles, gases and/or microorganisms, and (iii) one or more inlet ports for allowing air to enter the mask, wherein the total cross-sectional area of the one or more inlet ports is less than about 6.5 cm2.

Preferably, the size of the one or more ports is adjustable.

According to another aspect of the present invention, there is provided a face mask for filtering airborne particles, gases and/or micro-organisms, the face mask comprising:- (i) a cover for positioning over the mouth and nose of a wearer, (ii) one or more filters for filtering airborne particles, gases and/or microorganisms, and (iii) one or more inlet ports for allowing air to enter the mask, wherein the size of the one or more inlet ports is adjustable.

Preferably, the total cross-sectional area of the one or more inlet ports is less than about 6.5 cm2.

Preferably, the mask comprises one or more outlet ports for allowing air to exit the mask.

Preferably, the cross-sectional area of the one or more ports is adjustable.

Preferably, the total cross-sectional area of the one or more inlet ports is less than about 3.5 cm2.

Preferably, one or more of the one or more inlet ports allow air to exit the mask. As such, it is preferred that one or more of the inlet ports are also outlet ports for allowing air to exit the mask.

Preferably, one or more of the one or more inlet ports only allow air to enter the mask. That is, they allow one-way airflow only.

Preferably, the mask comprises one or more one-way valves for permitting air to enter the mask therethrough and preventing air from exiting the mask therethrough.

Preferably, the mask comprises one or more one-way valves for permitting air to exit the mask therethrough and preventing air from entering the mask therethrough.

Preferably, the mask comprises one or more inlet ports and one or more outlet ports.

Preferably, one or more of the one or more outlet ports only allow air to exit the mask. That is, they allow one-way airflow only.

Preferably, the one or more inlet ports comprise a one-way valve for permitting air to enter the mask through the port and preventing air from exiting the mask through the port.

Preferably, the one or more outlet ports comprise a one-way valve for permitting air to exit the mask through the port and preventing air from entering the mask through the port.

Preferably, the cross-sectional area of the one more ports is adjustable to increase the cross-sectional area thereof.

Preferably, one or more of the one or more ports comprise a removable insert for adjusting the cross-sectional area of the port when removed therefrom.

Preferably, the cross-sectional area of the one or more ports is adjustable between a first cross-sectional area and a second cross-sectional area.

Preferably, the port is of a first cross-sectional area without the insert positioned therein and of a second cross-sectional area with the insert positioned therein, wherein the first cross-sectional area is greater than the second cross-sectional area.

Preferably, the mask comprises two inlet ports with removable inserts and the second cross-sectional area of each port is less than about 3.25 cm2.

Preferably, the mask comprises two inlet ports with removable inserts and the second cross-sectional area of each port is less than about 1.75 cm2.

Preferably, the mask comprises two inlet ports with removable inserts and the first cross-sectional area of each port is greater than about 3.25 cm2.

Preferably, the one or more removable inserts comprise a channel formed therein and/or therethrough.

Preferably, the channel is shaped to direct the passage of air flowing therethrough.

Preferably, the channel is shaped to direct air flowing therethrough onto the face of a wearer.

Preferably, the channel is shaped to direct air flowing therethrough onto an inside surface of the cover.

Preferably, the channel is curved.

As will be appreciated, an inside surface of the cover is the surface of the cover which is on the inside of the face mask, in use, facing towards the wearer.

Preferably, the position and/or orientation of the one or more inserts is adjustable.

Preferably, the position and/or orientation of the one or more inserts is adjustable to change the direction of airflow exiting the insert, for example the channel.

Preferably, the one or more inserts are rotatable to change the direction of airflow exiting the insert, for example the channel.

Preferably, the one or more ports comprise a passage and the one or more inserts are positioned within the passage.

Preferably, the mask comprises one or more baffles for directing the flow of air within the mask.

Preferably, the one or more baffles are shaped and/or positioned to direct air onto the face of a wearer.

Preferably, the one or more baffles are shaped and/or positioned to direct air onto an inside surface of the cover.

Preferably, the position and/or orientation of the one or more baffles is adjustable.

Preferably, the position and/or orientation of the one or more baffles is adjustable to change the direction of airflow within the mask.

Preferably, one or more of the one or more baffles are provided on one or more of the one or more inserts.

Preferably, the one or more inserts comprise one or more baffles for directing the flow of air within the mask.

Preferably, the cross-sectional area of one or more of the one or more ports is adjustable by constricting a flexible part thereof.

Preferably, the rate of airflow through one or more of the one or more ports is adjustable via an adjustable valve, for example a butterfly valve or a gate valve.

Preferably, the rate of airflow through one or more of the one or more ports is adjustable via a flap.

Preferably, in use, the one or more inlet ports are positioned near the surface of the face of a wearer.

Preferably, in use, the one or more inlet ports are positioned within about 5 cm from the surface of the face of a wearer, preferably within about 3 cm.

Preferably, the mask comprises one or more inlet ports at or near a first side thereof and one or more outlet ports at or near a second side thereof.

Preferably, the cover comprises an air impermeable material.

Preferably, the cover comprises a flexible material.

Preferably, the cover is contoured to match the shape of the face of a wearer.

Preferably, the cover comprises a transparent material.

Within this specification, reference to a transparent material means a material which can be seen through. For example, in the context of the present invention, it is possible to see part of a person's face through a transparent material.

Preferably, the cover comprises a material selected from silicone, polyvinyl chloride (PVC), thermoplastic elastomers (TPE) or polyurethane.

Preferably, the thickness of the cover is between about 0.1 mm and about 5 mm.

Preferably, one or more of the one or more ports comprise a filter for filtering airborne particles, gases and/or micro-organisms.

Preferably, the mask comprises one or more filter cartridges connected to one or more of the one or more ports.

Preferably, the one or more filter cartridges comprise a filter.

Preferably, the filter is removable.

Preferably, one or more of the one or more ports comprises a first mating part for engagement with a second mating part on the filter cartridge.

Preferably, the first mating part is a female mating part, for example an aperture, and the second mating part is a male mating part, for example a protrusion.

Alternatively, the first mating part is a male mating part, for example a protrusion and the second mating part is a female mating part, for example an aperture.

Preferably, the filter is at least an FFP1 filter and more preferably an FFP2 or FFP3 filter, for example comprising interlaced layers of polypropylene fibres.

FFP1, FFP2 and FFP3 are different types of filter materials, classified according to filtration performance in BS EN149.

Preferably, the filter comprises an electret.

Preferably, the filter comprises a non-woven fibrous material.

Preferably, the filter comprises a laminate, preferably a laminate of spun-bonded and melt-bonded non-woven material.

Preferably, the filter comprises polypropylene (PP), polyethylene, polyethylene terephthalate (PET) or a fluoropolymer.

Preferably, the one or more filter cartridges are removable.

Preferably, the one or more filter cartridges comprise a plurality of apertures in an outer surface thereof.

Preferably, the one or more ports are positioned at or near the sides of the cover.

Preferably, the one or more inlet ports are positioned at or near the sides of the cover.

In the context of the present invention, the sides of the cover are adjacent in use to a wearer's cheeks, the top proximal to the bridge of the nose and the base proximal to the chin of the wearer.

Preferably, the one or more filter cartridges protrude in a rearward direction from the cover.

In the context of the present invention, it will be appreciated that "a rearward direction" is with reference to the face of a wearer of the mask. That is, with the mask positioned on the face of a wearer, it is preferred that the one or more filter cartridges protrude in the opposite direction to the forward-facing position of the face of the wearer. Put another way, it is preferred that the filter cartridges protrude in a direction pointing behind the wearer of the mask.

Preferably, in use, the one or more filter cartridges are positioned at the sides of a wearer's neck.

Preferably, in use, the one or more filter cartridges are positioned against a wearer's neck.

Preferably, in use, the one or more filter cartridges are positioned below the ears of a wearer.

Preferably, one or more of the one or more filter cartridges comprise a one-way valve for permitting air to enter the mask through the port and preventing air from exiting the mask through the port.

Preferably, one or more of the one or more filter cartridges comprise a one-way valve for permitting air to exit the mask through the port and preventing air from entering the mask through the port.

Preferably, the filter is removably attached to the filter cartridge.

This allows the filter to be replaced with a clean filter after use.

This is particularly advantageous because it means that the filter cartridges can be re-used.

Preferably, the filter comprises one or more folds and/or pleats. This increases the surface area of the filter and increases the filtering capacity of the filter.

Preferably, the mask comprises a fan for increasing the flow rate of air entering the face mask through one or more of the one or more ports.

Preferably, the face mask comprises one or more straps for securing the face mask on a wearer's head.

Preferably, the mask comprises a head strap for positioning around the head of a wearer and/or a neck strap for positioning behind the neck of a wearer.

Preferably, one or more of the one or more filter cartridges are attached to the neck strap.

Preferably, one or more of the one or more filter cartridges are attached to the neck strap via a mechanical fastening, such as hook and look material or via a channel formed within the filter cartridge for passage of the neck strap therethrough.

Preferably, the reusable parts of the face mask are UV stable.

Preferably, the reusable parts of the face mask are washable.

Preferably, the reusable parts of the face mask comprise the cover and the filter cartridge, excluding the filter.

Preferably, the face mask is a respirator.

According to another aspect of the present invention, there is provided a kit comprising a face mask as described herein and a plurality of inserts as described herein.

Preferably, the kit comprises at least two different inserts.

Preferably, the kit comprises one or more inserts comprising channels of different shapes and/or cross-sectional areas.

It will be appreciated that reference to "one or more" includes reference to "a plurality".

Within this specification, the term "about" means plus or minus 20%, more preferably plus or minus 100/0, even more preferably plus or minus 5%, most preferably plus or minus 2%.

Within this specification embodiments have been described in a way which enables a clear and concise specification to be written, but it is intended and will be appreciated that embodiments may be variously combined or separated without parting from the invention. For example, it will be appreciated that all preferred features described herein are applicable to both aspects of the invention.

DETAILED DESCRIPTION

Example embodiments of the present invention will now be described with reference to the accompanying Figures, in which:-Figure 1 shows a face mask as described herein positioned against the face of a wearer; Figure 2 shows a cross-sectional view of a face mask as described herein through the line C-C shown in Figure 1; Figure 3 shows an enlarged view of a port of the mask shown in Figures 1 and 2; Figure 4 shows a face mask provided with one-way valves; Figure 5 shows an enlarged view of a filter cartridge attached to the mask; Figure 6 shows a cross-sectional view of a face mask as described herein showing the filter cartridges attached to the neck strap; and Figure 7 shows an example of a mask in which a baffle is provided on one of the inserts.

The present invention relates to a mask which provides more comfort for a wearer.

In particular, the present invention provides a mask which is lightweight and easy to wear and provides the wearer with a cool, comfortable experience when wearing the mask.

With reference to the Figures, the face mask 1 includes a cover 2 made from an air-impermeable material, which extends over the wearer's nose and mouth and is contoured to match the shape of the face.

In the example shown, the cover 2 is made from a flexible material, so that it can deform to match the contours of the wearer's face without needing an additional, deformable component between the cover 2 and the face. Suitable materials for the cover include silicone, polyvinyl chloride (PVC), thermoplastic elastomers (TPE) or polyurethane and the thickness of the cover is typically be in the range 0.1 mm to 5 mm.

Whilst the mask 1 shown in the examples includes a transparent cover 2, it will be appreciated that non-transparent covers 2 could alternatively be used.

In the example shown, the edge of the cover is moulded into a lip 3, so that the lip 3 deforms when the mask 1 is fitted to the face and an air-tight seal is made between the mask 1 and the wearer's face.

Filter cartridges 4a, 4b containing a filter 6a, 6b are attached to ports 7a, 7b, either side of the cover 2, to filter the air that is inhaled and exhaled by the wearer 5. In the examples shown in Figures 1 to 3 and 5 to 7, each port 7a, 7b functions as both an inlet port and an outlet port. The cartridges 4a, 4b may be removable, so that they may be replaced once the filter 6a, 6b has become clogged or contaminated. The filters 6a, 6b include folds or pleats to increase the surface area that is in contact with the air flow.

In order to allow air to flow into and out of the filter cartridges 4a, 4b, each filter cartridge includes a plurality of apertures 17 in an outer surface thereof.

As shown with reference to Figure 2, the ports 7a, 7b are positioned next to the wearer's cheek.

The cartridges 4a, 4b form a leak-tight seal with the cover 2 when fitted to the ports 7a, 7b. Alternatively, the cartridges 4a, 4b may be firmly attached to the cover 2 and designed so that they can be opened by a user, to allow access to and replacement of a filter 6a, 6b therein.

In the examples shown, the filter cartridges 4a, 4b connect to the cover 2 via the insertion of the filter cartridges into the ports 7a, 7b on either side of the cover 2.

With particular reference to Figure 3, each port 7a, 7b comprises an opening 8a, 8b which leads to the interior of the mask 1 via a passage 9a, 9b.

At the inner end of each passage 9a, 9b an insert 10a, 10b is provided. Each insert 10a, 10b includes a channel 11a, 11b which is shaped to direct incoming air onto the wearer's face.

In addition, as shown in Figure 7, baffles 13 can be used to direct the air flow onto specific parts of the wearer's face or onto parts of the mask 1, to help clear condensation that may have formed on the inside surface 12 of the cover 2. Multiple ports 7 can be used to direct air in different directions. The baffles 13 can be user-adjustable, so that the wearer can choose where the air is directed. As shown in Figure 7, in one example a baffle 13 can be provided on an insert 10a. In this example, the insert forms part of an inlet port 7b so that air which enters the mask through the port 7b is directed on to the face of a wearer. Alternatively, or in addition, the baffles 13 can be provided elsewhere, for example positioned within or at the end at the passages 9a, 9b. Baffles 13 can be provided in or near one or both of the ports 7a, 7b.

With reference to the enlarged image of the port shown in Figure 3, each port has a cross-sectional area between the insert 10a and the opening 8a taken along line A-A. In the example shown, the cross-sectional area of each port along line A-A is 5 cm2 which means that, without the insert 10a positioned therein, the cross-sectional area of each port is 5 cm2. As a result, if the inserts 10a, 10b were removed, the total cross-sectional area of all ports in the mask 1 shown in the examples would be 10 cm2, although it will be appreciated that in other examples, the total cross-sectional area of all ports without inserts could be in the range of about 7 cm2 to about 20 cm2.

With the inserts 10a, 10b positioned within the ports, the cross-sectional area of each port is reduced to the cross-sectional area of the channel 11a, 11b taken along the line B-B. In the example shown, the cross-sectional area along line B-B is 3 cm2 which means that, with the insert 10a positioned therein, the cross-sectional area of each port is 3 cm2. As a result, if the inserts 10a, 10b are in place, the total cross-sectional area of all ports in the mask 1 shown in the examples would be 6 cm2 At a total cross-sectional area of 6.5 cm2, if air is entering the mask at 6 1/mm, the ports 7a, 7b will have air flowing through them at a velocity of 15.4 cm/s. This is sufficient to provide a significant cooling to the face of a wearer. The cooling can be improved further by directing the incoming air to a wearer's face, for example by the use of baffles 13 or an insert 10a, 10b with a shaped channel 11a, 11b, as discussed further below.

This cooling can also be improved by reducing the total cross-sectional area of the ports further. For example, this can be achieved by the use of the inserts 10a, 10b which have a cross-sectional area taken along line B-B of only 1.5 cm2. This means that, in a mask with two inlet ports, the total cross-sectional area of all channels 11a, lib in the mask 1 would be 3 cm2. As noted elsewhere herein, for maximum cooling effect, it is preferred that the total cross-sectional area of the channels 11a, 11b is less than 3.5 cm2.

With a total cross-sectional area of 3.5 cm2, if air is entering the mask at 6 1/mm, the channels 11a, 11b, and thus the ports 7a, 7b, will have air flowing through them at a velocity of 28.6 cm/s. The cooling effect is aided further by the shaped nature of the channels 11a, 11b, which direct air onto a wearer's face.

The provision of the inserts 10a, 10b, which are removable, is particularly advantageous, because it means that the cross-sectional area of the ports can be adjusted. This is beneficial, for example, to optimise the functionality of the face mask to different conditions. For example, if limited cooling is required, the inserts 10a, 10b can be removed. If more cooling is required, the inserts 10a, 10b can be positioned within the ports 7a, 7b. It will also be appreciated that only a single insert 10a, 10b could be provided, resulting in an intermediate cooling effect.

It will further be appreciated that the mask 1 could be provided as a kit with inserts having channels of different sizes and shapes according to the different cooling requirements of the mask.

Further, the inserts themselves can be adjusted, for example rotated, within the ports to change the direction of airflow. For example, whilst in the examples shown air is directed onto the face of a wearer, air could, instead, be directed onto the inside surface 12 of the cover 2 to prevent the build-up of condensation on the mask. In one example, a first insert 7a could be orientated to direct air onto the wearer's face and a second insert 7b could be orientated to direct air onto the inside surface of the cover 2.

The cross-sectional area of the ports 7a, 7b could also be adjusted in other ways, for example by constriction of a flexible part of the air passage 9a, 9b adjacent to the opening 8a, 8b of the port 7a, 7b, or by movement of a restricting flap, in a similar way to a butterfly valve or gate valve.

Adjustment of the total cross-sectional area of the ports 7a, 7b allows the mask 1 to be configured either as a mask which provides a low pressure drop during high flow rates, or as a mask that provides enhanced comfort from a noticeable stream of air striking the face.

To provide noticeable cooling, the ports 7a, 7b are positioned relatively near the surface of the face of a wearer; otherwise the air flow will decelerate as it enters the mask and lose its effect. In the example shown, the inner end of the ports 7a, 7b, as defined in the example shown by the inner end 14a, 14b of the channels 11a, 11b of the inserts 10a, 10b is about 2cm from the face.

It is preferred that the inner end of the ports should be less than 5 cm from the face and more preferably, less than 3 cm from the face.

In the examples shown in Figures 1 to 3 and 5 to 7, each port 7a, 7b operates as both an inlet port for the passage of fresh air into the mask as a wearer inhales and as an outlet port for the passage of exhaled air out of the mask 1 as the wearer exhales. However, it will be appreciated that the ports 7a, 7b could be provided with one-way valves such that they operate as either inlet or outlet ports. For example, as shown in Figure 4, the first port 7a could be provided as an inlet port and the second port 7b could be provided as an outlet port.

In this way, one port 7b can be used as an exhalation valve, which, when used in combination with a less restrictive filter 6, or without a filter 6, allows exhaled air to pass out of the mask freely 1 but prevents the flow of inhaled air through the less restrictive route.

With the use of two valves, one allowing the through-flow of inhaled air through a first port and one allowing the through-flow of exhaled air through a second port, the inhaled air follows a different route to the exhaled air. This allows different filter materials to be used for inhaled and exhaled air and reduces the amount of exhaled air which is inhaled at the beginning of each breath.

Whilst the ports 7a, 7b in the examples shown herein are to the side of the mask, it will be appreciated that a port and/or valve for the exit of inhaled air out of the mask could be placed in front of the wearer's mouth, so that the minimum amount of warm, exhaled air passes over the wearer's face and the inside surface 12 of the cover 2.

As shown in Figure 4, in which the cartridges 4a, 4b are provided with valves 15a, 15b, these can take the form of a flap valve using a disc or small sheet of elastomeric or silicone material as the 'flap'. In the example shown, the first cartridge 4a is provided with a valve 15a to prevent exit of exhaled air but allow entry of fresh air into the mask 1. The second cartridge is provided with a valve 15b to prevent entry of fresh air but to allow exit if exhaled air from the mask 1.

Whilst the valves 15a, 15b are incorporated into the filter cartridges 4a, 4b in Figure 4, it will be appreciated that they could, alternatively be fitted within the ports 7a, 7b, for example at the connection points for the filter cartridges 4a, 4b.

The mask 1 may also include a fan (not shown), to provide a larger flow rate of air for cooling and comfort than is provided by inhalation alone. In this example, the fan would be placed upstream of the port(s), to accelerate the air passing through the port(s) and onto the face. Separate routes into and out of the mask 1 would be required for inhaled and exhaled air, respectively.

The mask 1 includes a first elastic strap 16a attached to it, via heat bonding or adhesive bonding or mechanical fastening, to secure the mask 1 onto the wearer's head. The mask also includes a second elastic strap 16b which passes around the wearer's neck. The second strap 16b can also be attached to the mask via heat bonding or adhesive bonding or mechanical fastening.

Conveniently, in one example, the filter cartridges 4a, 4b can be attached to the strap 16b. As shown in Figure 6, this can, for example, be via hook and loop material 18a, 18b or via a channel (not shown) in the filter cartridge 4a, 4b for passage of the strap 16b therethrough.

The materials of construction of the re-usable parts of the mask 1 are selected to be resistant to cleaning and disinfection techniques, including rinsing in alcohol or bleach and exposure to strong UV light.

It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present invention and without diminishing its attendant advantages. It is therefore intended that such changes and modifications are covered by the appended claims.

Claims

CLAIMS1. A face mask for filtering airborne particles, gases and/or micro-organisms, the face mask comprising:- (i) a cover for positioning over the mouth and nose of a wearer, (ii) one or more filters for filtering airborne particles, gases and/or microorganisms, and (iii) one or more inlet ports for allowing air to enter the mask, wherein the total cross-sectional area of the one or more inlet ports is less than about 6.5 cm2.
2. A face mask according to claim 1, wherein the size of the one or more portsis adjustable.
3. A face mask for filtering airborne particles, gases and/or micro-organisms, the face mask comprising:- (i) a cover for positioning over the mouth and nose of a wearer, (ii) one or more filters for filtering airborne particles, gases and/or microorganisms, and (iii) one or more inlet ports for allowing air to enter the mask, wherein the size of the one or more inlet ports is adjustable.
4. A face mask according to any preceding claim, wherein the cross-sectional area of the one or more ports is adjustable.
5. A face mask according to any preceding claim, wherein one or more of the one or more ports comprise a removable insert for adjusting the cross-sectional area of the port when removed therefrom.
6. A face mask according to any preceding claim, wherein the cross-sectional area of the one or more ports is adjustable between a first cross-sectional area and a second cross-sectional area.
7. A face mask according to claim 5 or 6, wherein the port is of a first cross-sectional area without the insert positioned therein and of a second cross-sectional area with the insert positioned therein, wherein the first cross-sectional area is greater than the second cross-sectional area.
8. A face mask according to claim 7, wherein the mask comprises two inlet ports with removable inserts and the second cross-sectional area of each port is less than about 3.25 cm2.
9. A face mask according to claim 7 or 8, wherein the mask comprises two inlet ports with removable inserts and the second cross-sectional area of each port is less than about 1.75 cm2.
10. A face mask according to any of claims 5 to 9, wherein the one or more removable inserts comprise a channel formed therein and/or therethrough.
11. A face mask according to claim 10, wherein the channel is shaped to direct the passage of air flowing therethrough.
12. A face mask according to claim 10 or 11, wherein the channel is shaped to direct air flowing therethrough onto the face of a wearer and/or onto an inside surface of the cover.
13. A face mask according to any of claims 10 to 12, wherein the channel is curved.
14. A face mask according to any of claims 5 to 13, wherein the position and/or orientation of the one or more inserts is adjustable.
15. A face mask according to any of claims 5 to 14, wherein the one or more ports comprise a passage and the one or more inserts are positioned within the passage.
16. A face mask according to any preceding claim, wherein the mask comprises one or more baffles for directing the flow of air within the mask.
17. A face mask according to claim 16, wherein the position and/or orientation of the one or more baffles is adjustable.
18. A face mask according to claim 16 or 17, wherein one or more of the one or more ports comprise a removable insert for adjusting the cross-sectional area of the port when removed therefrom and wherein one or more of the one or more baffles are provided on one or more of the one or more inserts.
19. A face mask according to any preceding claim, wherein the mask comprises one or more inlet ports at or near a first side thereof and one or more outlet ports at or near a second side thereof.
20. A face mask according to any preceding claim, wherein the cover comprises a transparent material.
21. A face mask according to any preceding claim, wherein the mask comprises one or more filter cartridges connected to one or more of the one or more ports.
22. A face mask according to claim 21, wherein the mask comprises a neck strap for positioning behind the neck of a wearer and wherein one or more of the one or more filter cartridges are attached to the neck strap.
23. A face mask according to any preceding claim, wherein the filter is at least an FFP1 filter.
24. A kit comprising a face mask according to any preceding claim and a plurality of inserts as described in any of claims 5, 7 to 15 or 18.
25. A kit according to claim 24, wherein the kit comprises at least two different inserts.