EP3848094A1

EP3848094A1 - Face mask

Info

Publication number: EP3848094A1
Application number: EP20151482.5A
Authority: EP
Inventors: Yifei YANG
Original assignee: Koninklijke Philips NV
Current assignee: Koninklijke Philips NV
Priority date: 2020-01-13
Filing date: 2020-01-13
Publication date: 2021-07-14

Abstract

A face mask with an outlet valve comprising a first disk and a second disk configured to rotate relative to each other. Each disk contains at least one opening. The outlet valve is configured to open when the relative rotation between the first and second disks is such that the at least one opening in the first disk is aligned with the at least one opening in the second disk, and to close when the relative rotation is such that the at least one opening in each disk is blocked by the other disk.

Description

FIELD OF THE INVENTION

The invention relates to the field of face masks, and in particular to face masks with valves.

BACKGROUND OF THE INVENTION

Face masks (or breathing masks) are used in a range of applications to filter the air inhaled by a wearer.
For example, face masks are commonly worn in cities with high levels of air pollution to filter particulate matter from the air inhaled by users. Small particulate matter can penetrate the lungs if inhaled, with the smallest particles able to enter the blood stream, and can cause a number of health conditions. The World Health Organization (WHO) estimates that air pollution leads to 4.2 million premature deaths each year.
Many face masks include a valve to regulate the air flow through the mask. This is typically a check valve that opens during exhalation, to reduce breathing resistance and improve the comfort of wearing the mask, and closes during inhalation, to ensure that only filtered air is inhaled.
Check valves used in face masks typically comprise a flap that opens in one direction when there is sufficient air pressure and closes when the air pressure falls below a certain threshold. A disadvantage of these check valves is that the flap does not open fully, meaning that breathing resistance is not reduced enough to make breathing through the mask easy and comfortable. The resistance of these valves may be reduced further by increasing the size of the valve; however, a larger valve flap requires a larger clearance space, making the face mask bulky.
Some face masks additionally incorporate a fan to improve air flow through the mask. In face masks with flap check valves, the resistance of the check valve reduces the effectiveness of the fan ventilation, and increasing the size of the valve increases the distance between the valve and the fan, since a larger clearance space is required, also reducing the ventilation efficiency. In addition to this, the fan pulls against the flap of the valve, preventing the valve from closing completely.
Check valves in which the operation of the valve is pressure driven are known as passive check valves; check valves may also be operated by a power source. Power-operated check valves are known as active check valves. Current active check valves are too large to be suitable for use in face masks and consume a large amount of electricity, and the respiratory sensors that are required to trigger the operation of active check valves are expensive and also require a large amount of battery power.
There is therefore a need for a face mask comprising a valve with reduced resistance that requires little or no power consumption to operate and is suitable for use in fan-assisted face masks.

SUMMARY OF THE INVENTION

The invention is defined by the claims.
According to examples in accordance with an aspect of the invention, there is provided a face mask comprising: an air chamber; a filter that forms a boundary between the air chamber and outside the air chamber; and an outlet valve that is adapted to vent the air chamber to the outside, the outlet valve comprising: a first disk; and a second disk, wherein the first and second disks are configured to rotate relative to each other, wherein each disk contains at least one opening, and the outlet valve is configured to open when the first and second disks are in relative positions such that the at least one opening in the first disk is aligned with the at least one opening in the second disk, and to close when the first and second disks are in relative positions such that the at least one opening in each disk is blocked by the other disk.
This valve structure enables the outlet valve to allow a higher air flow through it than a check valve which uses a flap that does not open fully. This structure therefore reduces the resistance of the valve, making breathing out through the face mask easier and more comfortable.
Since the opening mechanism of the outlet valve does not require clearance space, unlike valve structures that involve a flap, the size of the outlet valve can be increased to allow more air through without increasing the size of the outlet valve in the direction of the air flow. This improves the ease and comfort of breathing out, without making the face mask bulkier.
When the face mask also comprises a fan for ventilation, the reduced resistance means that the fan ventilation is more effective. Since the valve design does not necessitate clearance space for a flap, the fan may be placed closer to the outlet valve, further increasing the ventilation efficiency of the fan. Furthermore, unlike flap check valves that may be prevented from closing properly by the fan pulling against the flap, the operation of the outlet valve of the present invention is not affected by the fan.
In some embodiments, the at least one opening has a tear shape. This shape maximizes the opening area for a given valve surface area, thus decreasing the resistance of the outlet valve. This shape also allows minimal relative rotation of the disks to open and close the outlet valve, reducing power usage when an electrical actuation system is used to open and close the valve.
In some embodiments, the first and second disks each contain a plurality of openings at intervals in the range 8 degrees to 30 degrees.
In this way, only a small amount of relative rotation is required to open and close the outlet valve. This reduces the size of the battery required when an electrical actuation system is used to open and close the outlet valve, making the face mask lighter and more comfortable to wear, and requires less pressure when the relative rotation of the disks is pressure-driven, reducing the effort required when breathing out.
The first and second disks may each contain a plurality of openings at 20 degree intervals.
This spacing is designed to minimize the relative rotation required to open or close the outlet valve while allowing each opening to be large enough that the air flow is not restricted. This means that, in examples where the relative rotation of the disks is pressure-driven, the pressure required to fully open the outlet valve is lower, and in examples where the relative rotation of the disks is battery-powered, a smaller battery can be used.
In some embodiments, the surface of each disk that faces the other disk comprises a set of ridges, the number of ridges on each disk corresponding to the number of openings in each disk, and wherein the at least one ridge on the first disk is configured to align with the at least one ridge on the second disk, such that each aligned pair of ridges provides a barrier between an opening in the first disk and an adjacent opening in the second disk when the outlet valve is closed.
In this way, air is prevented from leaking through the outlet valve when the valve is closed.
The aligned ridges may interlock to limit the range of relative rotation. This prevents too much relative rotation from occurring when the outlet valve is opening or closing, making sure that the openings do not start to realign when the outlet valve is closing and that each disk does not start to block the at least one opening in the other disk again when the outlet valve is opening.
In some embodiments, at least one of the first and second disks has a fan-like structure that is adapted to allow air flow to cause the relative rotation of the first and second disks.
This structure means that a source of electricity is not required to cause the relative rotation of the disks, making the face mask lighter and reducing the costs of manufacturing and using the face mask.
In some embodiments, the face mask further comprises a flow sensor and a controller for controlling the relative rotation of the first and second disks in response to a signal generated by the flow sensor.
In this way, the amount of relative rotation is not dependent on the air pressure, reducing the effort required when breathing out through the mask.
The flow sensor may comprise a flap valve and an electric switch, and the controller may comprise an electromagnet circuit which is actuated by the electric switch.
In some embodiments, the flap valve has a conductive flap portion which forms the contact of the electric switch.
The conductive flap portion may provide electrical contact between first and second contacts of the electric switch when the flap valve is open.
In this way, the outlet valve uses a second valve to quickly detect when air flow is in a particular direction. The outlet valve is thus able to quickly respond to changes in the direction of air flow, opening when the air flow is in one direction and closing when the air flow is in the opposite direction.
This detection system has the additional advantage of not requiring expensive and complex circuitry to detect the direction of air flow, keeping the cost of manufacturing and using the face mask low.
In some embodiments, the electromagnet circuit of the controller comprises: a solenoid; a power source connected to the solenoid; and a permanent magnet attached to either the first disk or the second disk, wherein relative rotation between the first and second disks is caused by the magnetic force between the solenoid and the permanent magnet.
In this way, the relative rotation of the disks may be caused using a relatively low amount of power. This means that a small battery may be used, keeping the mask light and comfortable to wear.
In some embodiments, the solenoid is configured to generate linear motion perpendicular to the first and second disks, and the controller further comprises: a grooved structure perpendicular to the first and second disks and adapted to convert linear motion to rotational motion and rotate one of the first and second disks; and a spring adapted to return said one of the first and second disks to its original position.
In some embodiments, the face mask further comprises a printed circuit board, wherein the outlet valve is configured to have a detachable interface with the printed circuit board.
In this way, the filter and outlet valve may be manufactured and sold separately from the more expensive printed circuit board. This reduces the cost of replacing the filter and reduces waste by avoiding the need to replace the printed circuit board when the filter needs replacing.
These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings, in which:

FIG. 1 is a diagram of a face mask, according to an embodiment of the invention;
FIG. 2 is a diagram of a valve for a face mask in an open position, according to an embodiment of the invention;
FIG. 3 is a diagram of a valve for a face mask in a closed position, according to an embodiment of the invention;
FIG. 4 is a diagram of a valve for a face mask, according to an embodiment of the invention;
FIG. 5 is a diagram of an open valve for a face mask in which the relative rotation of the valve disks is controlled by a flow sensor and controller, according to an embodiment of the invention;
FIG. 6 is a diagram of a closed valve for a face mask in which the relative rotation of the valve disks is controlled by a flow sensor and controller, according to an embodiment of the invention;
FIG. 7 is a diagram of a mechanism that converts linear motion to rotational motion and rotates the disk of a valve for a face mask, according to an embodiment of the invention;
FIG. 8 is another diagram of a face mask, according to an embodiment of the invention; and
FIG. 9 shows a magnetic circuit and one possible magnet arrangement configuration.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The invention will be described with reference to the Figures.
It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the apparatus, are intended for the purposes of illustration only, and are not intended to limit the scope of the invention. These and other features, aspects and advantages of the apparatus of the present invention will become better understood from the following description, appended claims and accompanying drawings. It should be understood that the same reference numerals are used throughout the Figures to indicate the same or similar parts.
According to a concept of the invention, there is proposed a face mask with an outlet valve comprising a first disk and a second disk configured to rotate relative to each other. Each disk contains at least one opening. The outlet valve is configured to open when the relative rotation between the first and second disks is such that the at least one opening in the first disk is aligned with the at least one opening in the second disk, and to close when the relative rotation is such that the at least one opening in each disk is blocked by the other disk.
Embodiments are at least partly based on the realization that an outlet valve comprising two disks that rotate relative each other to allow or block air flow through openings in the disks provides less resistance than check valve designs currently used in face masks. The lower resistance makes breathing through the face mask easier and more comfortable.
Illustrative embodiments may, for example, be employed in face masks worn to filter particulate matter from inhaled air in places with high levels of air pollution.
Figure 1 illustrates a face mask 10 according to an embodiment of the invention. The face mask 10 comprises an air chamber 12, a filter 14 that forms a boundary between the air chamber 12 and outside the air chamber, and an outlet valve 16.
The face mask 10 is configured to allow air to pass out of the air chamber 12 to the outside through the outlet valve 16, but to only allow air to enter the air chamber 12 from the outside through the filter 14. This ensures that inhaled air is filtered, for example to remove pollutants, while quickly ventilating exhaled air to reduce breathing resistance and reduce the humidity and temperature of the air inside the air chamber 12.
Figure 2 illustrates an example of the outlet valve 16 in an open position, according to an embodiment of the invention.
The outlet valve comprises a first disk 20 and a second disk (not visible in Figure 2), wherein the first and second disks are configured to rotate relative to each other. The disks in Figure 2 are circular, but other shaped disks may be used.
Each disk contains openings 25: in Figure 2 there are eighteen openings 25 in each disk, but any number of openings may be used. The openings 25 may be placed at regular intervals around each disk; the size of these intervals may be chosen in order to minimize the rotation required to open and close the valve. In some embodiments, the intervals at which the openings 25 are placed are in the range 8 degrees to 30 degrees, but any interval angle up to 180 degrees may be used.
In some embodiments, the openings 25 are at intervals of 20 degrees, such that a rotation of just 10 degrees is required to open or close the valve. In Figure 2, the openings 25 are tear shaped, extending out from the center of the disk 20, but other shapes, such as a slice shape or a triangle, may be used.
As shown in Figure 2, when the valve is in an open position, the disks are in relative positions such that the openings 25 in the first disk 20 are aligned with the openings in the second disk, allowing air to pass through the openings.
Figure 3 illustrates an example of the outlet valve 16 in a closed position, according to an embodiment of the invention.
When the outlet valve is in a closed position, the openings 25 in the first disk 20 are blocked by a second disk 30. The openings in the second disk 30 are not shown in Figure 3, as they are blocked by the first disk 20. The outlet valve may be opened and closed by rotating one of the first disk 20 and the second disk 30 to align or block the openings 25.
The disks 20 and 30 may be made of a lightweight material, such as a polymer or a porous material, in order to minimize the force required to cause relative rotation of the disks.
Figure 4 illustrates another example of an outlet valve 16, according to an embodiment of the invention. The outlet valve 16 comprises a first disk 20 and a second disk 30, containing openings 25 as described above, and further comprising a set of ridges 40 on the surface of each disk that faces the other disk. The number of ridges 40 on each disk may correspond to the number of openings 25 in each disk, such that each ridge 40 is between two openings. Each ridge 40 may extend radially outwards from the center of the disk.
The at least one ridge 40 on the first disk is configured to align with the at least one ridge on the second disk, such that each aligned pair of ridges provides a barrier between an opening 25 in the first disk 20 and an opening in the second disk.
In some embodiments, the first disk 20 and second disk 30 are positioned close enough to one another that the aligned ridges 40 are able to interlock. This limits the range of relative rotation of the first disk 20 and second disk 30: the disks are only able to rotate in either direction until a ridge 40 on one disk comes into contact with a ridge on the other disk.
In some embodiments, at least one of the first disk 20 and second disk 30 has a fan-like structure that is adapted to allow air flow to cause the relative rotation of the first and second disks.
Thus, an air flow is against the valve is converted by the fan-like structure into a rotational torque which then rotates one of the discs relatively to the other. Fan blades which are angularly offset from the air flow direction may be used to generate this torque.
In other embodiments, the face mask 10 comprises a flow sensor and a controller for controlling the relative rotation of the first disk 20 and second disk 30 in response to a signal generated by the flow sensor.
In some embodiments, the flow sensor comprises a flap valve and an electric switch, and the controller comprises an electromagnet circuit which is actuated by the electric switch. The flap valve may have a conductive flap portion that forms the contact of the electric switch. Other types of flow sensor and controller will be apparent to the skilled person.
Figure 5 illustrates an example of an outlet valve 16 in which the relative rotation of the first disk 20 and second disk 30 is controlled by a flow sensor and controller, according to an embodiment of the invention. The outlet valve 16 is in an open position.
Figure 6 illustrates the same outlet valve 16 in a closed position.
The flow sensor comprises an electric switch 51 and a flap valve 52. The flap valve 52 has a conductive flap portion that forms the contact of the electric switch 51 when the flap valve 52 touches the electric switch 51, by providing electrical contact between first and second contacts of the electric switch 51.
The flap valve 52 is configured to be actuated by the air pressure caused by exhalation, such that the flap valve 52 opens when the wearer of the face mask 10 breathes out. When the flap valve 52 opens, the conductive flap portion forms the contact of the electric switch 51. When the wearer of the face mask 10 breathes in, the flap valve 52 closes, such that it no longer provides contact between first and second contacts of the electric switch 51.
The controller comprises an electromagnet circuit which is actuated by the electric switch 51, and a permanent magnet 53 attached to either the first disk or the second disk. The electromagnet circuit comprises a solenoid and a power source connected to the solenoid. An iron core may be added to the solenoid to increase the strength of the solenoid's magnetic field without increasing the power consumption. The solenoid is configured such that the magnetic force between the solenoid and the permanent magnet 53 causes relative rotation between the first disk 20 and the second disk 30. For example, the permanent magnet 53 may be attached to the first disk 20, as shown in Figures 5 and 6, and the solenoid may be positioned on the second disk 30, or the permanent magnet may be attached to the second disk 30, and the solenoid may be positioned on the first disk 20.
In some embodiments, the electric switch 51 is part of the electromagnet circuit, such that the solenoid produces a magnetic field when the switch is closed. In other embodiments, the electric switch may be part of a circuit that, when closed, acts as a trigger to switch off an electromagnet circuit.
A spring may provide a bias to the closed state so that when the electromagnet circuit is turned off, the bias closes the valve. Alternatively, a magnetic bias (of permanent magnets) may be used to close the valve, and this magnetic bias is overcome by the electromagnet circuit, which generates a stronger magnetic force.
In yet other embodiments, a first closed electromagnet circuit is formed when the flap valve 52 opens to touch the electric switch 51, and a second closed electromagnet circuit, with a reverse current to the first electromagnet circuit, is formed when the flap valve 52 is closed. This means that the magnetic force between the solenoid and the permanent magnet 53 acts in a first direction when the flap valve 52 is open and in a second direction when the flap valve 52 is closed.
In some embodiments, the motion generated by the magnetic force between the solenoid and the permanent magnet 53 is the rotation of either the first disk 20 or the second disk 30; in other embodiments, the solenoid is configured to generate linear motion perpendicular to the first and second disks, and the controller is adapted to convert linear motion to rotational motion and rotate one of the first and second disks. For example, a grooved structure perpendicular to the first and second disks may be used to convert the linear motion generated by the solenoid to rotational motion and rotate one of the first and second disks. A mechanism, such as a spring, may then be used to return the disk rotated by the grooved structure to its original position. Other mechanisms for converting linear to rotational motion and for returning a rotated disk to its original position will be apparent to the skilled person.
Figure 7 illustrates an example mechanism 70 for converting linear motion to rotational motion to rotate a disk and for returning a rotated disk to its original position.
The mechanism comprises a grooved structure 72, a linear slider 74 and a spring 76. The grooved structure is connected to the first disk 20 in Figure 7, but may instead be connected to the second disk 30, and is perpendicular to the first and second disks. In Figure 7, the grooved structure is a cylinder with a spiral groove, but other shapes may be used.
When the electromagnet circuit is switched on, the magnetic force between the solenoid and the permanent magnet 53 causes the linear slider 74 to move either towards or away from the first disk 20. Part of the linear slider 74 sits in the groove of the grooved structure 72, such that the linear motion of the linear slider 74 causes the grooved structure 72, and the first disk 20 connected to the grooved structure 72, to rotate.
The spring 76 is attached to the linear slider 74 and positioned between the grooved structure 72 and the linear slider 74, such that the motion of the linear slider compresses the spring 76 if the linear slider 74 moves towards the first disk 20 and extends the spring if the linear slider 74 moves away from the first disk 20. When the electromagnet circuit is switched off, the magnetic force between the solenoid and the permanent magnet 53 is no longer present, and the spring 76 returns to its original length, moving the linear slider 74 away from the first disk 20. The motion of the linear slider 74 rotates the grooved structure 72 and first disk 20 back to their original positions.
Figure 8 illustrates an example of a face mask 10 including a printed circuit board 80. The printed circuit board 80 controls the opening and closing of the outlet valve 16 using any of the methods described above and may comprise a power control module. The power control module may comprise an amplifier, a capacitor and resistors. Designs for the printed circuit board 80 will be apparent to the skilled person. The printed circuit board 80 may use the same power supply as the outlet valve 16.
In some embodiments, the printed circuit board 80 has a detachable interface with the outlet valve 16, and the outlet valve 16 is integrated with the filter 14. This allows the filter 14 and outlet valve 16 to be sold separately from the printed circuit board 80. Methods of constructing a detachable interface between the outlet valve 16 and the printed circuit board 80 will be apparent to the skilled person.
In other embodiments, the printed circuit board 80 is integrated with one of the disks of the outlet valve 16, while the other disk of the outlet valve 16 is integrated with the filter 14, and the two disks of the outlet valve 16 may be detached from each other. This allows the filter 14 and one disk of the outlet valve 16 to be sold separately from the printed circuit board 80 and the other disk of the outlet valve 16.
In yet other embodiments, the printed circuit board 80 is integrated with the outlet valve 16, and the printed circuit board 80 and outlet valve 16 may be detached from the filter 14. This allows the filter 14 to be sold separately from the printed circuit board 80 and outlet valve 16.
There are various magnet configurations that can be used to provide the rotational control.
Figure 9 shows a permanent magnet 53 attached to one of the discs which is to be rotated, e.g. the first disc 20. A second permanent magnet 54 holds the disc in the position for closing the valve. An electromagnet circuit comprises a solenoid 80 which implements an electromagnet and a power source 82. The solenoid is coupled to the power source by the switch 51. The switch 51 is formed by the flap valve as explained above. This flap valve can be a small valve as it does not need to allow a large flow of air; it is only used to detect a pressure difference, and hence the direction of air flow, i.e. to detect inhalation or exhalation.
In the left image, the switch 51 is open so the solenoid is not powered. The permanent magnets 53,54 align (as they have opposite poles) to hold the valve in the closed state. The switch 51 being open may correspond to the flap valve being closed (i.e. with no flow to open the flap, as explained above). This is represented schematically in Figure 9.
In the right image, the switch 51 is closed (the flap valve is open) so the solenoid is powered. The magnetic force overcomes the magnetic force of the permanent magnet 54 and the disc rotates to cause a new alignment. In some embodiments, the permanent magnet 53 and the disk it is attached to are configured to be rotated by 10 degrees relative to the permanent magnet 54.
Instead of using a permanent magnet to define the default closed valve position, a torsional spring or linear spring (e.g. pushing against a control tab) may be used.
The permanent magnet may be in the center of the disc (e.g. mounted on about a rotation shaft) or at the periphery.
There may instead be first and second electromagnets, one for each position of the disc.
To reduce power consumption, light weight materials may be used for the valve, such as polymers or porous materials.
This invention relates only to the detection of flow and opening of a valve in response. The invention may be used in combination with any known mask control scheme. It may be used in active masks (with a fan) or passive masks. When used with active masks, any known control approach for the fan may be used.
Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality.
The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.
If the term "adapted to" is used in the claims or description, it is noted the term "adapted to" is intended to be equivalent to the term "configured to".
Any reference signs in the claims should not be construed as limiting the scope.

Claims

A face mask (10) comprising:
an air chamber (12);

a filter (14) that forms a boundary between the air chamber and outside the air chamber; and

an outlet valve (16) that is adapted to vent the air chamber to the outside, the outlet valve comprising:
a first disk (20); and

a second disk (30), wherein the first and second disks are configured to rotate relative to each other,

wherein each disk (20, 30) contains at least opening (25), and the outlet valve (16) is configured to open when the first and second disks are in relative positions such that the at least one opening (25) in the first disk (20) is aligned with the at least one opening (25) in the second disk (30), and to close when the first and second disks are in relative positions such that the at least one opening in each disk is blocked by the other disk.
The face mask (10) of claim 1, wherein the at least one opening (25) has a tear shape.
The face mask (10) of claim 1 or 2, wherein the first and second disks (20, 30) each contain a plurality of openings (25) at intervals in the range 8 degrees to 30 degrees.
The face mask (10) of claim 3, wherein the first and second disks (20, 30) each contain a plurality of openings (25) at 20 degree intervals.
The face mask (10) of any preceding claim, wherein the surface of each disk (20, 30) that faces the other disk comprises a set of ridges (40), the number of ridges on each disk corresponding to the number of openings (25) in each disk, and wherein the at least one ridge (40) on the first disk (20) is configured to align with the at least one ridge (40) on the second disk (30), such that each aligned pair of ridges provides a barrier between an opening in the first disk and an adjacent opening in the second disk when the outlet valve is closed.
The face mask (10) of claim 5, wherein the aligned ridges (40) interlock to limit the range of relative rotation.
The face mask (10) of any preceding claim, wherein at least one of the first and second disks (20, 30) has a fan-like structure that is adapted to allow air flow to cause the relative rotation of the first and second disks.
The face mask (10) of any preceding claim, comprising a flow sensor and a controller for controlling the relative rotation of the first and second disks in response to a signal generated by the flow sensor.
The face mask (10) of claim 8, wherein the flow sensor comprises a flap valve (52) and an electric switch (51), and the controller comprises an electromagnet circuit which is actuated by the electric switch (51).
The face mask (10) of claim 9, wherein the flap valve (52) has a conductive flap portion which forms the contact of the electric switch (51).
The face mask (10) of claim 10, wherein the conductive flap portion provides electrical contact between first and second contacts of the electric switch (51) when the flap valve (52) is open.
The face mask (10) of any one of claims 8 to 11, wherein the electromagnet circuit of the controller comprises:
a solenoid;

a power source connected to the solenoid; and

a permanent magnet (53) attached to either the first disk (20) or the second disk (30),

wherein relative rotation between the first and second disks is caused by the magnetic force between the solenoid and the permanent magnet.
The face mask (10) of claim 12, wherein the solenoid is configured to generate linear motion perpendicular to the first and second disks (20, 30), and wherein the controller further comprises:
a grooved structure (72) perpendicular to the first and second disks and adapted to convert linear motion to rotational motion and rotate one of the first and second disks (20, 30); and

a spring (76) adapted to return said one of the first and second disks (20, 30) to its original position.
The face mask (10) of any preceding claim, further comprising:
a printed circuit board (80),
wherein the outlet valve (16) is configured to have a detachable interface with the printed circuit board (80).