US20240400176A1

US20240400176A1 - Breathable mask and body thereof

Info

Publication number: US20240400176A1
Application number: US18/678,349
Authority: US
Inventors: Chih-Cheng Shiue
Original assignee: QBAS Co Ltd
Current assignee: QBAS Co Ltd
Priority date: 2023-05-31
Filing date: 2024-05-30
Publication date: 2024-12-05
Also published as: US20240400177A1; CN118529230A; TWM661221U; CN222539002U; CN222272324U; TWM660082U

Abstract

A breathable mask and a body thereof are provided. The body includes a main frame, a lens and a waterproof skirt. The waterproof skirt has a partition which divides the interior of the body into an upper chamber and a lower chamber. When the user wears the breathable mask, the partition is seated above the user's nose, the user's eyes are accommodated in the upper chamber, and the user's nose and mouth are accommodated in the lower chamber. The waterproof skirt also includes a bridge disposed across the lower chamber and divides the lower chamber into a nasal chamber and a mouth chamber below the nasal chamber. The bridge has an opening and an orinasal one-way valve adjacent to the opening. The orinasal one-way valve only allows a unidirectional fluid communication from the nasal chamber to the mouth chamber.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS

This patent application claims the benefit of U.S. Prov. Ser. No. 63/505,238 filed on May 31, 2023, which is incorporated in its entirety by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a full-face mask for water activities, particularly a mask for snorkeling that allows a user to breathe through both of his/her nose and mouth.

Descriptions of the Related Art

Some of the current full-face snorkel masks (FFSMs) have adopted a shunting design for an intake and an exhaust of airflows. In this design, the lower chamber of the mask (the chamber that covers the user's mouth and nose) will communicate with the exhaust tunnel provided along the periphery of the body of the mask. During snorkeling underwater, if the user wants to discharge the accumulated water in the mask, the user must exhale heavily through the mouth to overcome the strong external water pressure in order to successfully force the accumulated water through the drain valve.
However, because the lower chamber of the mask needs to accommodate the user's nose and mouth, it inevitably occupies a considerable volume, and is also in communication with the exhaust tunnel. In addition, the actual path of the exhaust tunnel is quite long, which further increases the actual space of the lower chamber. Therefore, the actual space of the lower chamber is still unable to be effectively controlled as anticipated. Therefore, when the user attempt to drain the accumulated water by exhaling heavily using the mouth, the exhalation pressure created in this space is obviously insufficient. Not only does it fail to overcome the water pressure and drain the accumulated water successfully, but the accumulated water is brought into and stays within the exhaust tunnel at the periphery of the body of the mask. After the user finishes exhaling, the accumulated water naturally flows back into the body of the mask. As a matter of fact, the accumulated water is not fully discharged outward as desired.
In other words, the design of FFSMs generally lacks efficient drainage during underwater activities. The user must surface and discharge the accumulated water outward, or take off the mask to pour out the accumulated water, which is quite troublesome and significantly reduces the enjoyment of snorkeling.
In view of this, the industry is striving to design a snorkeling equipment that can solve some or all of the above problems.

SUMMARY OF THE INVENTION

The applicant has made significant improvement in addressing the aforementioned problems in U.S. patent application Ser. No. 18/128,677. Specifically, that US patent application is to further divide the lower chamber into a nasal chamber and a mouth chamber by providing a bridge to form a nasal chamber and a mouth chamber. In some embodiments, an orinasal one-way valve can be provided on the bridge, allowing only one-way fluid communication from the nasal chamber to the mouth chamber. Furthermore, the exhaust channel communicates with the nasal chamber, but not with the mouth chamber. This design enables the mouth chamber to function as an independent chamber with a small volume. Therefore, when the user exhales heavily to drain the accumulated water using the mouth, this small independent chamber will provide a large pressure, which can easily overcome the water pressure and successfully do the water drainage. Moreover, because the mouth chamber and the exhaust tunnel do not communicate with each other, there is no way for the accumulated water to be brought into the exhaust tunnel and then to flow back into the mouth chamber However, with this design, although the user can inhale through the mouth (bringing fresh air from the nasal chamber to the mouth chamber), the user is restricted in exhaling and must use the nose to exhale instead. For users who are accustomed to breathing through their mouths, this may cause some inconvenience, necessitating further consideration and improvement.
Based on the above reasons, an objective of the present invention is to provide a breathable mask. The breathable mask is provided with an additional bridge in the lower chamber, accommodating the mouth and nose, to further divide the lower chamber into a nasal chamber and a mouth chamber. The intake airflow is guided to the nasal chamber, and the exhaust airflow is also guided out of the nasal chamber. In addition, there is a conditional communication between the nasal chamber and the mouth chamber. For example, the bridge is allowed to be provided with an opening and an orinasal one-way valve which only allows fluid communication from the nasal chamber to the oral chamber. Under this shunting structure for intake and exhaust of airflows, on top of that the user can still breathe naturally through the nose, furthermore, when the user wishes to inhale using the mouth, fresh air can be brought from the outside into the nasal chamber via the intake conduit, the upper chamber and the intake one-way valve in sequence, and then continuously into the mouth chamber through the opening and the orinasal one-way valve on the bridge for inhalation through the mouth. In addition, when the user wishes to exhale using the mouth, the dirty air can reversely enter the nasal chamber through the opening of the bridge and then quickly enter the exhaust passage to be discharged outward through the exhaust conduit.
In the case that when the user wants to drain the accumulated water within the mask by exhaling heavily through the mouth, given that the exhaust airflow presenting high pressure and speed, and running in a short time, it tends not to escape through the opening with a “limited open area” on the bridge. Instead, it tends to overcome the water pressure and is discharged outward along with the accumulated water through the drain valve. Therefore, even if a little accumulated water splashes upward from the opening into the nasal chamber, it will not cause discomfort to the user's nose.
To achieve the above objective, the present invention discloses a breathable mask, which includes a body and a breathing tube. The breathing tube is in fluid communication with an interior of the body. The breathing tube includes an intake conduit and an exhaust conduit independent of each other. The body includes a main frame, a lens, a waterproof skirt, an intake passage and an exhaust passage. The lens is embedded within the main frame. The waterproof skirt is at least partially embedded with the main frame and the lens. The waterproof skirt is configured to suitably fit a face of a user. The waterproof skirt has a partition to divide the interior of the body into an upper chamber and a lower chamber, whereby when the user wears the breathable mask through a fastening device, the partition is seated above a nose of the user, eyes of the user are accommodated in the upper chamber, and the nose and a mouth of the user are accommodated in the lower chamber. The intake passage is formed from the intake conduit to the lower chamber. The exhaust passage is formed from the lower chamber to the exhaust conduit; The waterproof skirt further includes a bridge disposed across the lower chamber and dividing the lower chamber into a nasal chamber and a mouth chamber below the nasal chamber, whereby when the user wears the breathable mask, the nose of the user is accommodated in the nasal chamber, and the mouth of the user is accommodated in the mouth chamber. The intake passage is in fluid communication with the nasal chamber, the exhaust passage is in fluid communication with the nasal chamber, and the nasal chamber and the mouth chamber are suitably in fluid communication with each other through the bridge. The bridge has an opening and an orinasal one-way valve adjacent to the opening. The orinasal one-way valve only allows a unidirectional fluid communication from the nasal chamber to the mouth chamber.
Also, to achieve the above objective, the present invention further discloses a body of a breathable mask. The body includes a main frame, a lens and a waterproof skirt. The lens is embedded within the main frame. The waterproof skirt is at least partially embedded with the main frame and the lens. The waterproof skirt is configured to suitably fit a face of a user. The waterproof skirt has a partition to divide the interior of the body into an upper chamber and a lower chamber, whereby when the user wears the breathable mask through a fastening device, the partition is seated above a nose of the user, eyes of the user are accommodated in the upper chamber, and the nose and a mouth of the user are accommodated in the lower chamber. The waterproof skirt further includes a bridge disposed across the lower chamber and dividing the lower chamber into a nasal chamber and a mouth chamber below the nasal chamber, whereby when the user wears the breathable mask, the nose of the user is accommodated in the nasal chamber, and the mouth of the user is accommodated in the mouth chamber. The bridge has an opening and an orinasal one-way valve adjacent to the opening, and the orinasal one-way valve only allows a unidirectional fluid communication from the nasal chamber to the mouth chamber.
In an example, when the user wears the breathable mask, the opening is adapted to be distal from nostrils of the user, relative to the orinasal one-way valve which is adapted to be proximal to the nostrils of the user.
In an example, a total open area of the opening ranges between 60 and 200 square millimeters (mm²).
In an example, the opening has an inner boundary, and the bridge is formed with a central inner edge, in which the inner boundary and the central inner edge define a distance therebetween ranging from 20 to 80 millimeters (mm).
In an example, the distance between the inner boundary and the central inner edge ranges between 20 and 50 millimeters (mm).
In an example, the opening is formed by a plurality of holes spaced apart from each other.
In an example, the orinasal one-way valve has a central fixed portion and two diaphragms extending outward from the central fixed portion, the central fixed portion is fixed to the bridge, and the two diaphragms are only opened when airflows pass therethrough from the nasal chamber to the mouth chamber.
In an example, the exhaust passage includes an exhaust tunnel jointly defined by the waterproof skirt and an inner surface of the lens, and the exhaust tunnel extends along a periphery of the body.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a front schematic view of the breathable mask according to an embodiment of the present invention.

FIG. 1B is a rear schematic view taken along the line 1 b-1 b in FIG. 1A.

FIG. 2 is a sagittal cross-sectional view of the breathable mask of FIG. 1B, showing the spatial relationship between the breathable mask and the user wearing that breathable mask.

FIG. 3A is a coronal cross-sectional view of the breathable mask of FIG. 1B, showing the intake airflow when the user inhales through the mouth and/or nose.

FIG. 3B is a further coronal cross-sectional view of the breathable mask of FIG. 1B, showing the exhaust airflow when the user exhales through the mouth and/or nose.

FIG. 3C is a sagittal cross-sectional view of the breathable mask of FIG. 1B, showing the exhaust airflow when the user exhales naturally through the mouth.

FIG. 4A is a coronal cross-sectional view of the breathable mask of FIG. 1B, showing the exhaust airflow when the user exhales heavily through the mouth.

FIG. 4B is a sagittal cross-sectional view of the breathable mask of FIG. 1B, showing that when the user exhales heavily through the mouth, only a small amount of air passes through the opening, and most of the air and accumulated water is discharged outward through the drain valve.

FIG. 5 is a sagittal cross-sectional view of the breathable mask of FIG. 1B, showing the spatial structure of the opening and the orinasal one-way valve of provided on bridge.

DESCRIPTION OF THE PREFERRED EMBODIMENT

It shall be appreciated that the following description of the embodiments is only to explain the contents of the present invention, but not to limit the invention as claimed. Elements not directly related to the present invention, such as the head strap that secures the mask to the user's head, are omitted from the description, and the dimensions as depicted for all elements in the drawings are just for easy understanding and do not intend to limit their actual scales.
An embodiment of the present invention is shown in FIG. 1A, FIG. 1B and FIG. 2 . FIG. 1A is a front schematic view of the breathable mask 1 of the present invention. FIG. 1B is a rear view taken along the line 1 b-1 b of FIG. 1A. FIG. 2 is a sagittal cross-sectional view of the breathable mask 1 of FIG. 1A.
The breathable mask 1 includes a breathing tube 11 and a body 13. The breathing tube 11 is in fluid communication with the interior of the body 13. The breathing tube 11 has an interior which is longitudinally partitioned into an intake conduit 112 and at least one exhaust conduit 114. The breathing tube 11 of this embodiment is illustrated by two exhaust conduits 114 formed and longitudinally separated on both sides of the intake conduit 112, respectively. However, any variation in the number and position of the exhaust conduits 114 of the breathing tube 11 shall be applicable to the present invention.
The body 13 includes a main frame 13 a, a lens 13 b, a waterproof skirt 13 c, an intake passage, an exhaust passage and a drain valve 13 f. The lens 13 b is embedded within the main frame 13 a. The waterproof skirt 13 c is at least partially embedded with the main frame 13 a and the lens 13 b.
The waterproof skirt 13 c is capable of suitably fitting on the face of a user UR. The waterproof skirt 13 c has a partition 13 c 1. The partition 13 cl is provided to divide the interior of the body 13 into an upper chamber 202 and a lower chamber 204. The waterproof skirt 13 c further includes a bridge 13 c 2 disposed across the lower chamber 204 to divide the lower chamber 204 into a nasal chamber 204 a and a mouth chamber 204 b below the nasal chamber 204 a. When the user wears the breathable mask 1 through a fastening device (which is usually an elastic head strap connecting two sides of the main frame 13 a, not shown), the partition 13 cl is seated above the nose of the user UR so that the eyes of the user UR are accommodated in the upper chamber 202, the nose of the user UR is accommodated in the nasal chamber 204 a, and the mouth of the user UR is accommodated in the mouth chamber 204 b.
The intake passage is formed from the intake conduit 112 to the lower chamber 204, more specifically, is formed between the lower end portion of the breathing tube 11 and the nasal chamber 204 a. Preferably, the body 13 has two intake one-way valves 13 d symmetrically provided on both outer sides of the partition 13 c 1, allowing the inhaled air to unidirectionally pass through the intake passage and enter the lower chamber 204. In this aspect, the intake passage is defined by the upper chamber 202 and the intake one-way valves 13 d, and is in fluid communication with the nasal chamber 204 a. The positions of the two intake one-way valves 13 d are not limited, and they can be provided on the partition 13 cl instead.
With further reference to FIGS. 3A to 3C, the exhaust passage is formed from the lower chamber 204 to the exhaust conduits 114. More specifically, the exhaust passage is in fluid communication with nasal chamber 204 a. The exhaust passage mainly includes two exhaust tunnels 132, which are formed between the lower end portion of the breathing tube 11 and the nasal chamber 204 a. Each exhaust tunnel 132 may extend along the periphery of the body 13 and may be jointly defined by the waterproof skirt 13 c and an inner surface of the lens 13 b. In this embodiment, the main frame 13 a does not form parts of the exhaust tunnels 132.
In addition, the bridge 13 c 2 has an opening 20 and an orinasal one-way valve 13 e adjacent to the opening 20 so that the nasal chamber 204 a and the mouth chamber 204 b is capable of being in fluid communication through the opening 20 and the adjacent orinasal one-way valve 13 e on the bridge 13 c 2. The orinasal one-way valve 13 e only allows a unidirectional fluid communication from the nasal chamber 204 a to the mouth chamber 204 b.
Preferably, when the user UR wears the breathable mask 1, the opening 20 is adapted to be relatively distal from nostrils of the user UR, while the orinasal one-way valve 13 e is adapted to be proximal to the nostrils of the user UR. Specifically, the opening 20 is located in front of the orinasal one-way valve 13 e. When the user UR wears the breathable mask 1, the nostrils of the user UR are more proximal to the orinasal one-way valve 13 e and are distal from the opening 20. The total open area of the opening 20 may range between 60 and 200 square millimeters (mm²). The opening 20 may be formed by a plurality of holes spaced apart from each other. In each figure, the opening 20 is shown to be composed of two holes spaced apart from each other. The sum of the open areas of the two holes is the total open area of the opening 20. However, in other embodiments, the opening 20 may be composed of a single hole or more than two holes spaced apart from each other. In this case, the open area of the single hole or the total open area of those holes still remains between 60 and 200 mm². That is to say, although the opening 20 shown in each figure is composed of two rectangular holes, in practice, the number and shape of holes of the opening 20 are not limited, and can even be designed as an opening with a mesh or grid shape containing many holes, which is also feasible.
With further reference to FIG. 5 , the opening 20 has an inner boundary. The distance d between the inner boundary and a central inner edge of the bridge 13 c 2 ranges between 20 and 80 millimeters (mm), preferably between 20 and 50 millimeters (mm).
In addition, as shown in FIGS. 2 and 5 , the orinasal one-way valve 13 e has a central fixed portion 13 e 1 and two diaphragms 13 e 2 extending outward from the central fixing portion 13 e 1. The central fixed portion 13 e 1 is fixed to the bridge 13 c 2, and the two diaphragms 13 e 2 are only opened when the airflows pass therethrough from the nasal chamber 204 a to the mouth chamber 204 b. It shall be appreciated that although the one-way valves shown in the figure (for example, the intake one-way valves 13 d and the orinasal one-way valve 13 e) are all wing-type one-way valves, the actual shapes and numbers are not limited. In other embodiments, mushroom-type or pivot-type one-way valves may also be feasible.
Reference is made to FIG. 3A now, in which the intake path is depicted by the airflow shown in the solid lines. When the user UR wears the breathable mask 1 and inhales through the nose, fresh air will enter the intake conduit 112 of the breathing tube 11, pass through the upper chamber 202, and then enter the nasal chamber 204 a through the intake one-way valves 13 d for the nose of the user UR to inhale. In addition, when the user UR inhales through the mouth, the fresh air in the nasal chamber 204 a will mainly pass through the orinasal one-way valve 13 e provided on the bridge 13 c 2, and then enter the mouth chamber 204 b for the mouth of the user UR to inhale.
On the other hand, the exhaust path can be referred to by the airflow shown in the dotted lines of FIG. 3B and FIG. 3C. Because the drain valve 13 f is kept closed due to water pressure, the mouth chamber 204 b is substantially an enclosed space. When the user UR chooses to exhale through the nose, the exhaust airflow naturally proceeds through the path of least resistance, that is, the dirty air as exhaled will flow upwards along the two exhaust tunnels 132, which are independently provided between the two exhaust conduits 114 and the nasal chamber 204 a, and then will be discharged outwards through the exhaust conduits 114 provided in the breathing tube 11. Furthermore, when the user UR exhales naturally through the mouth, the dirty air as exhaled will enter the nasal chamber 204 a from the mouth chamber 204 b through the opening 20 on the bridge 13 c 2. Then, it will flow upward along the two exhaust tunnels 132 and be discharged outwards through the exhaust conduits 114 provided in the breathing tube 11.
In addition, when the user UR exhales heavily through the mouth, the exhaust path can be referred to by the airflow shown in the dotted lines of FIG. 4A and FIG. 4B. Due to the barrier of the bridge 13 c 2 and the limited open area of the opening 20, the accumulated water in the mouth chamber 204 b will be discharged outward through the drain valve 13 f, and will not significantly splash back into the nasal chamber 204 a. Therefore, the vicinity of the nose of the user UR can be kept relatively dry and comfortable. Through the structure of the aforementioned breathable mask 1, the user UR can freely inhale and exhale through the nose and/or mouth. Moreover, the space of the mouth chamber 204 b is very small, and the drain valve 13 f can be specifically designed to face the user's mouth. This enables the user UR to more easily overcome the water pressure to drain water underwater without surfacing, thus significantly saving the user's physical energy.
In other implementations, an additional exhaust one-way valve (not shown) can be provided at, for instance, the connection between the exhaust tunnel 132 and the nasal chamber 204 a to further prevent the dirty air staying in the exhaust tunnel 132 from flowing back to the nasal chamber 204 a.
The technical content of the present invention mainly lies in a full-face mask that has an upper chamber and a lower chamber, wherein the lower chamber is further divided into a nasal chamber and a mouth chamber by a bridge. Additionally, this bridge is provided with opening(s) and an orinasal one-way valve. This technical concept can be applied to any form of full-face masks, and the disclosed figures only illustrate one type of breathable mask as an example. In other words, the structure of the main frame 13 a, the lens 13 b (i.e., the viewing window) and the waterproof skirt 13 c in the disclosed figures are only for illustration, and should not be misunderstood as limiting the scope of the present invention, whereby any type of mask modified based on the concept of the present invention also belongs to the scope of the present invention.
Furthermore, in the present invention, the lens 13 b is preferably a single-piece lens design, and the breathing tube is composed of a single intake conduit 112 and two exhaust conduits 114. In other embodiments, it is also feasible for the lens to be of a separated dual-lens design (i.e., a left-right separated dual-lens design). The exhaust conduits, exhaust tunnels or exhaust passages mentioned in the above embodiments are preferably designed to be bilaterally symmetrical. However, for the sake of clarity and conciseness, some descriptions only refer to one of them, which do not limit their number.
The design of other portions of the mask, such as the formation of the intake and exhaust conduits (whether integrated into a single breathing tube or separated into two or more tubes), as well as variations in the number, shapes and/or types of lens(es), frame(s) and intake and exhaust valves, are not the focus. The so-called breathing tube can be in the form extending directly outward from the top of the body of the mask, or can have the lower end portion being integrally extending from the lens 13 b, and then connected to the main portion of the breathing tube, as shown in FIG. 1B, to allow the main portion of the breathing tube and the interior of the body to achieve the desired fluid communication.
Therefore, the above embodiments are used only to illustrate the implementations of the present invention and to explain the technical features of the present invention, and are not used to limit the scope of the present invention. Any modifications or equivalent arrangements that can be easily accomplished by those skilled in the art (e.g., the number of the intake passages, the number of the exhaust passages, etc.) are considered to fall within the present invention, and the scope of the present invention should be limited by the claims of the patent application.

Claims

What is claimed is:

1. A breathable mask, comprising:

a body; and

a breathing tube in fluid communication with an interior of the body, the breathing tube including an intake conduit and an exhaust conduit independent of each other;

wherein the body comprises:

a main frame;

a lens embedded within the main frame;

a waterproof skirt, at least partially embedded with the main frame and the lens, the waterproof skirt being configured to suitably fit a face of a user, the waterproof skirt having a partition to divide the interior of the body into an upper chamber and a lower chamber, whereby when the user wears the breathable mask through a fastening device, the partition is seated above a nose of the user, eyes of the user are accommodated in the upper chamber, and the nose and a mouth of the user are accommodated in the lower chamber;

an intake passage formed from the intake conduit to the lower chamber; and

an exhaust passage formed from the lower chamber to the exhaust conduit;

characterized in that:

the waterproof skirt further comprises a bridge disposed across the lower chamber and dividing the lower chamber into a nasal chamber and a mouth chamber below the nasal chamber, whereby when the user wears the breathable mask, the nose of the user is accommodated in the nasal chamber, and the mouth of the user is accommodated in the mouth chamber; and

the intake passage is in fluid communication with the nasal chamber, the exhaust passage is in fluid communication with the nasal chamber, and the nasal chamber and the mouth chamber are suitably in fluid communication with each other through the bridge; and

the bridge has an opening and an orinasal one-way valve adjacent to the opening, and the orinasal one-way valve only allows a unidirectional fluid communication from the nasal chamber to the mouth chamber.

2. The breathable mask of claim 1, wherein when the user wears the breathable mask, the opening is adapted to be distal from nostrils of the user, relative to the orinasal one-way valve which is adapted to be proximal to the nostrils of the user.

3. The breathable mask of claim 2, wherein a total open area of the opening ranges 60 and 200 square millimeters (mm²).

4. The breathable mask of claim 3, wherein the opening has an inner boundary, and the bridge is formed with a central inner edge, in which the inner boundary and the central inner edge define a distance therebetween ranging from 20 to 80 millimeters (mm).

5. The breathable mask of claim 4, wherein the distance between the inner boundary and the central inner edge ranges between 20 and 50 millimeters (mm).

6. The breathable mask of claim 2, wherein the opening is formed by a plurality of holes spaced apart from each other.

7. The breathable mask of claim 2, wherein the orinasal one-way valve has a central fixed portion and two diaphragms extending outward from the central fixed portion, the central fixed portion is fixed to the bridge, and the two diaphragms are only opened when airflows pass therethrough from the nasal chamber to the mouth chamber.

8. The breathable mask of claim 1, wherein the exhaust passage includes an exhaust tunnel jointly defined by the waterproof skirt and an inner surface of the lens, and the exhaust tunnel extends along a periphery of the body.

9. A body of a breathable mask, comprising:

a main frame;

a lens embedded within the main frame;

characterized in that:

10. The body of claim 9, wherein when the user wears the breathable mask, the opening is adapted to be distal from nostrils of the user, relative to the orinasal one-way valve which is adapted to be proximal to the nostrils of the user.

11. The body of claim 10, wherein a total open area of the opening ranges between 60 and 200 square millimeters (mm²).

12. The body of claim 11, wherein the opening has an inner boundary, and the bridge is formed with a central inner edge, in which the inner boundary and the central inner edge define a distance therebetween ranging from 20 to 80 millimeters (mm).

13. The body of claim 12, wherein the distance between the inner boundary and the central inner edge ranges between 20 and 50 millimeters (mm).

14. The body of claim 10, wherein the opening is formed by a plurality of holes spaced apart from each other.

15. The body of claim 10, wherein the orinasal one-way valve has a central fixed portion and two diaphragms extending outward from the central fixed portion, the central fixed portion is fixed to the bridge, and the two diaphragms are only opened when airflows pass therethrough from the nasal chamber to the mouth chamber.