Patent Application
20230235828
The present disclosure relates generally to a respiratory mask, and in particular to a valve for a respiratory mask.
Respirators are used in contaminated environments where air cannot be inhaled directly because the air may be noxious and/or contain harmful gases or substances. A respirator typically comprises a positive pressure mask which seals around a face of a wearer to define a mask space between the positive pressure mask and the face of the wearer. The wearer inhales the air from the mask space. The positive pressure mask further includes an inlet for introducing breathable air into the mask space and an outlet for ensuring air exhaled by the wearer is expelled from the mask space. The air supply may be sourced from a pressurized air cylinder via one or more filters.
The outlet is usually in the form of a one-way exhalation valve which opens in response to a raised pressure within the mask space because of exhalation and which closes again as the pressure within the mask space lowers. In the positive pressure mask, the mask space is usually maintained at a positive pressure, i.e., a pressure slightly higher than atmospheric pressure, to ensure any leakage around a face seal of the mask is outwards to the environment rather than into the mask space. The positive pressure in the mask space may therefore require that a cracking or an opening pressure of the exhalation valve is also higher than atmosphere pressure. The exhalation valve therefore allows the exhaled air to be rapidly purged from the mask space.
In a first aspect, the present disclosure provides a valve for a respiratory mask. The valve includes a valve housing including a valve seat and an inlet. The valve further includes a valve flap at least partially received within the valve housing. The valve flap is sealingly engaged with the valve seat in a closed configuration and is disengaged from the valve seat in a plurality of open configurations. The valve flap includes a tubular projection extending away from the valve seat along a longitudinal axis. The plurality of open configurations includes a first open configuration and a second open configuration. The valve further includes a pin slidably received through the valve housing and coupled to the tubular projection. The pin and the valve flap are together movable along the longitudinal axis relative to the valve seat. The valve further includes a valve cage coupled to the valve housing. The valve further includes a central limiter coupled to the valve cage and extending towards the tubular projection along the longitudinal axis. The valve further includes a cap disposed on the valve flap opposite to the valve seat. The cap is engaged with the valve flap and movable along the longitudinal axis. The valve further includes a biasing member disposed between and engaged with the cap and the valve cage. The biasing member is configured to normally bias, via the cap, the valve flap to the closed configuration. In response to an inlet pressure applied at the inlet of the valve housing, the valve flap moves linearly, along the longitudinal axis, from the closed configuration to the first open configuration against the biasing of the biasing member. The linear movement of the valve flap from the closed configuration to the first open configuration causes a corresponding linear movement of the cap along the longitudinal axis. In the first open configuration of the valve flap, the central limiter engages with the tubular projection to prevent further movement of the tubular projection along the longitudinal axis, such that the valve flap transitions, in response to the inlet pressure, from the first open configuration to the second open configuration in order to remain disengaged from the valve seat. The valve flap at least partially deforms to transition from the first open configuration to the second open configuration.
In a second aspect, the present disclosure provides a respiratory mask. The respiratory mask includes a seal for sealing against and around a face of a wearer. The respiratory mask further includes a mask inlet adapted to be placed in fluid communication with a supply of air. The respiratory mask further includes a mask outlet through which a wearer's exhaled breath is emitted. The respiratory mask further includes a valve fluidly disposed in the mask outlet. The valve includes a valve housing including a valve seat and an inlet. The inlet is configured to receive the wearer's exhaled breath at an inlet pressure. The valve further includes a valve flap at least partially received within the valve housing. The valve flap is sealingly engaged with the valve seat in a closed configuration and is disengaged from the valve seat in a plurality of open configurations. The valve flap includes a tubular projection extending away from the valve seat along a longitudinal axis. The plurality of open configurations includes a first open configuration and a second open configuration. In each of the plurality of open configurations, the valve is configured to allow discharge of fluid through the mask outlet. The valve further includes a pin slidably received through the valve housing and coupled to the tubular projection. The pin and the valve flap are together movable along the longitudinal axis relative to the valve seat. The valve further includes a valve cage coupled to the valve housing. The valve further includes a central limiter coupled to the valve cage and extending towards the tubular projection along the longitudinal axis. The valve further includes a cap disposed on the valve flap opposite to the valve seat. The cap is engaged with the valve flap and movable along the longitudinal axis. The valve further includes a biasing member disposed between and engaged with the cap and the valve cage. The biasing member is configured to normally bias, via the cap, the valve flap to the closed configuration. In response to the inlet pressure at the inlet of the valve housing, the valve flap moves linearly, along the longitudinal axis, from the closed configuration to the first open configuration against the biasing of the biasing member. The linear movement of the valve flap from the closed configuration to the first open configuration causes a corresponding linear movement of the cap along the longitudinal axis. In the first open configuration of the valve flap, the central limiter engages with the tubular projection to prevent further movement of the tubular projection along the longitudinal axis, such that the valve flap transitions, in response to the inlet pressure, from the first open configuration to the second open configuration in order to remain disengaged from the valve seat. The valve flap at least partially deforms to transition from the first open configuration to the second open configuration.
In a third aspect, the present disclosure provides a valve for a respiratory mask. The valve includes a valve flap configured to prevent fluid flow through the valve in a closed configuration. The valve flap is further configured to allow fluid flow through the valve in each of a first open configuration and a second open configuration. The valve flap includes a tubular projection extending along a longitudinal axis. The valve further includes a central limiter extending towards the tubular projection along the longitudinal axis. The central limiter is stationary within the valve. The valve further includes a biasing member configured to normally bias the valve flap to the closed configuration. In response to an inlet pressure applied on the valve, the valve flap moves linearly, along the longitudinal axis, from the closed configuration to the first open configuration against the biasing of the biasing member. In the first open configuration of the valve flap, the central limiter engages with the tubular projection to prevent further movement of the tubular projection along the longitudinal axis, such that the valve flap transitions, in response to the inlet pressure, from the first open configuration to the second open configuration in order to allow fluid flow through the valve. In response to the inlet pressure, at least a portion of the valve flap deforms and moves non-linearly during the transition of the valve flap from the first open configuration to the second open configuration, such that an excitation frequency of the valve due to the inlet pressure changes and becomes different from a natural frequency of the valve.
The details of one or more examples of the disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the disclosure will be apparent from the description and drawings, and from the claims.
Exemplary embodiments disclosed herein may be more completely understood in consideration of the following detailed description in connection with the following figures. The figures are not necessarily drawn to scale. Like numbers used in the figures refer to like components. However, it will be understood that the use of a number to refer to a component in a given figure is not intended to limit the component in another figure labeled with the same number.
In the following description, reference is made to the accompanying figures that form a part thereof and in which various embodiments are shown by way of illustration. It is to be understood that other embodiments are contemplated and may be made without departing from the scope or spirit of the present disclosure. The following detailed description, therefore, is not to be taken in a limiting sense.
In the following disclosure, the following definitions are adopted.
As used herein, all numbers should be considered modified by the term “about”. As used herein, “a,” “an,” “the,” “at least one,” and “one or more” are used interchangeably.
As used herein as a modifier to a property or attribute, the term “generally”, unless otherwise specifically defined, means that the property or attribute would be readily recognizable by a person of ordinary skill but without requiring absolute precision or a perfect match (e.g., within +/−20% for quantifiable properties).
The term “about”, unless otherwise specifically defined, means to a high degree of approximation (e.g., within +/−5% for quantifiable properties) but again without requiring absolute precision or a perfect match.
As used herein, the terms “first” and “second” are used as identifiers. Therefore, such terms should not be construed as limiting of this disclosure. The terms “first” and “second” when used in conjunction with a feature or an element can be interchanged throughout the embodiments of this disclosure.
As used herein, “at least one of A and B” should be understood to mean “only A, only B, or both A and B”.
As used herein, the term “hazardous or potentially hazardous environmental conditions” may refer to environmental conditions that may be harmful to a human being, such as high noise levels, high ambient temperatures, lack of oxygen, presence of explosives, exposure to radioactive or biologically harmful materials, and exposure to other hazardous substances. Depending upon the type of safety equipment, environmental conditions and physiological conditions, corresponding thresholds or levels may be established to help define hazardous and potentially hazardous environmental conditions.
As used herein, the term “hazardous or potentially hazardous environments” may refer to environments that include hazardous or potentially hazardous environmental conditions. The hazardous or potentially hazardous environments may include, for example, chemical environments, biological environments, nuclear environments, fires, industrial sites, construction sites, agricultural sites, mining sites, or manufacturing sites.
As used herein, the term “an article of personal protective equipment (PPE)” may include any type of equipment or clothing that may be used to protect a user from hazardous or potentially hazardous environmental conditions. In some examples, one or more individuals, such as the users, may utilize the article of PPE while engaging in tasks or activities within the hazardous or potentially hazardous environment. Examples of the articles of PPE may include, but are not limited to, respiratory protection equipment (including disposable respirators, reusable respirators, powered air purifying respirators, self-contained breathing apparatus and supplied air respirators), facemasks, and any other suitable gear configured to protect the users from injury.
As used herein, the term “integral” means that the parts in are joined together as a single continuous part and are not separated from each other by other structures.
As used herein, the term “contaminants” refers to gases, vapors, and particles (including dusts, mists, and fumes) and/or other substances which may be present in air and may be harmful to a person.
As used herein, the term “exhaled breath” is air that is exhaled by a wearer wearing a respiratory mask.
As used herein, the term “exhalation valve” refers to a valve that is adapted for use on a respiratory mask to allow a fluid to exit an interior gas space of the respiratory mask when the valve is operatively disposed on the respiratory mask.
As used herein, the term “valve flap” refers to a sheet-like article that is capable of bending or flexing in response to a force exerted from a moving fluid.
As used herein, the term “unidirectional valve” refers to a valve that allows a fluid to pass through it in one direction but not the other.
The present disclosure relates to a valve for a respiratory mask. The respiratory mask may be a positive pressure mask. Further, the respiratory mask may be a part of an article of personal protective equipment (PPE), such as a respiratory protective equipment (RPE), a self-contained breathing apparatus (SCBA), a powered air purifying respirator (PAPR), a supplied air respirator (SAR), a pressure-demand supplied air respirator (PDSAR), and the like. The respiratory mask may be used in hazardous environmental conditions.
In some applications, an excitation frequency of an exhalation valve of a respiratory mask (e.g., a positive pressure full face mask) may be same at its natural frequency during an exhalation cycle (i.e., when a wearer exhales). The excitation of the exhalation valve at the natural frequency may lead to excessive fluttering in the exhalation valve. The excessive fluttering may cause discomfort to the wearer wearing the respiratory mask. In other words, the excessive fluttering in the exhalation valve may be annoying for the wearer. The excessive fluttering is more prominent around exhalation pressures generated during a speech of the wearer.
Further, the fluttering in the exhalation valve may occur predominantly around pressures generated during normal breathing. This does not conform to protocols of safety standards, such as EN 136, EN 137 which list the requirements of respiratory protective devices. Moreover, in some applications, for conventional respiratory masks, upon plotting a graph between facepiece pressure (i.e., a pressure inside the respiratory mask maintained by a demand valve) and time during normal breathing, many pressure peaks (i.e., excessive fluttering) or sharp peaks may be noticed in an exhale side of the graph because of the excessive fluttering in the exhalation valve. Presence of such sharp peaks in the exhale side may lead to discomfort for the wearer donning the respiratory mask.
One of the conventional techniques for reducing the fluttering in the exhalation valve comprises a use of two valve flaps (instead of a single valve flap) in total. The two valve flaps are arranged in such a way that the fluttering is reduced by damping vibrations produced in the exhalation valve during the exhalation cycle. However, a design of the exhalation valve comprising the two valve flaps is non-compliant with breathing resistance requirements in accordance with the safety standards.
Another conventional technique for reducing the fluttering in the exhalation valve proposes to increase a size of the exhalation valve. However, due to compact design requirements of the respiratory mask, the size of the exhalation valve cannot be increased to such an extent which can be useful in limiting the fluttering in the exhalation valve. Moreover, considering the compact design requirements, it may also be difficult to increase a size of a valve seat of the exhalation valve to reduce the fluttering.
Another conventional technique for reducing the fluttering in the exhalation valve proposes to adjust natural frequency of the exhalation valve. The natural frequency of the exhalation valve can be adjusted by varying characteristics of a biasing member. On one hand, with a low strength biasing member, the fluttering may further increase causing the discomfort to the wearer. On the other hand, with a high strength biasing member, the breathing resistance requirements may not be acceptable in accordance with the safety standards.
The present disclosure provides a valve for a respiratory mask. The valve includes a valve housing including a valve seat and an inlet. The valve further includes a valve flap at least partially received within the valve housing. The valve flap is sealingly engaged with the valve seat in a closed configuration and is disengaged from the valve seat in a plurality of open configurations. The valve flap includes a tubular projection extending away from the valve seat along a longitudinal axis. The plurality of open configurations includes a first open configuration and a second open configuration. The valve further includes a pin slidably received through the valve housing and coupled to the tubular projection. The pin and the valve flap are together movable along the longitudinal axis relative to the valve seat. The valve further includes a valve cage coupled to the valve housing. The valve further includes a central limiter coupled to the valve cage and extending towards the tubular projection along the longitudinal axis. The valve further includes a cap disposed on the valve flap opposite to the valve seat. The cap is engaged with the valve flap and movable along the longitudinal axis. The valve further includes a biasing member disposed between and engaged with the cap and the valve cage. The biasing member is configured to normally bias, via the cap, the valve flap to the closed configuration. In response to an inlet pressure applied at the inlet of the valve housing, the valve flap moves linearly, along the longitudinal axis, from the closed configuration to the first open configuration against the biasing of the biasing member. The linear movement of the valve flap from the closed configuration to the first open configuration causes a corresponding linear movement of the cap along the longitudinal axis. In the first open configuration of the valve flap, the central limiter engages with the tubular projection to prevent further movement of the tubular projection along the longitudinal axis, such that the valve flap transitions, in response to the inlet pressure, from the first open configuration to the second open configuration in order to remain disengaged from the valve seat. The valve flap at least partially deforms to transition from the first open configuration to the second open configuration.
In some cases, the valve may be an exhalation valve in the respiratory mask. Due to the at least partial deformation of the valve flap during the transition from the first open configuration to the second open configuration, at least a portion of the valve flap moves non-linearly during the transition of the valve flap from the first open configuration to the second open configuration. Due to the non-linear movement of at least the portion of the valve flap, an excitation frequency of the valve due to the inlet pressure is different from a natural frequency of the valve. This prevents the valve from exciting at the natural frequency during an exhalation cycle. As the valve is not excited at its natural frequency, the fluttering in the valve may be reduced. The reduced fluttering may further provide an improved comfort to a wearer donning the respiratory mask. Moreover, in contrast to some conventional positive pressure respiratory masks, the respiratory mask of the present disclosure may not be annoying for the wearer because of the reduced fluttering in the valve (i.e., the exhalation valve).
For the respiratory mask including the valve of the present disclosure, upon plotting the graph between the facepiece pressure and time during normal breathing, there are no sharp pressure peaks in the exhale side of the graph. Absence of sharp pressure peaks in the exhale side signifies the reduced fluttering in the valve and may therefore lead to improved comfort for the wearer donning the respiratory mask. For reducing the fluttering in the valve, the valve of the present disclosure includes only one valve flap in contrast to some conventional valves including two valve flaps. In other words, excessive vibrations may be damped in the valve by using only one valve flap. Moreover, to reduce the fluttering in the valve, the use of only one valve flap may reduce a cost of manufacturing the valve as compared to conventional valves having two valve flaps. The valve of the present disclosure is also compliant with the breathing resistance requirements in accordance with the safety standards.
In contrast to a conventional technique for reducing the fluttering in a valve by increasing a size of the valve, there is no requirement for increasing a size of any component in the valve of the present disclosure. Therefore, while reducing the fluttering in the valve of the present disclosure, compact design requirements of the respirator mask may also be met. This may further reduce a complexity in designing the valve for the respiratory mask.
In contrast to another conventional technique for reducing the fluttering in a valve by adjusting characteristics of a biasing member, there is no need to adjust the characteristics of the biasing member for reducing the fluttering in the valve of the present disclosure. In other words, to achieve the reduced fluttering in the valve, there may be no requirement to have the biasing member with a relatively lower strength or a relatively higher strength. Therefore, while providing an adequate strength of the biasing member, the proposed valve may have the reduced fluttering along with acceptable breathing resistance requirements in accordance with the safety standards.
Referring now to Figures,
The respiratory mask 100 may be attachable to hoses for delivering oxygen or other breathable gas, as well as adapters to accept hoses, filters and/or regulators specific to particular functions or to be used in particular environments.
The respiratory mask 100 further includes a mask inlet 110 adapted to be placed in fluid communication with a supply of air. In some cases, the mask inlet 110 is adapted to be placed in fluid communication with an outlet of an air filter (not shown). In some cases, the mask inlet 110 is adapted to be placed in fluid communication with an outlet of a pressurized air supply from a compressor. In some cases, a demand valve or a regulator valve (not shown) is provided and mounted on the mask inlet 110 for supplying breathing air under pressure in the respiratory mask 100 (i.e., a positive pressure mask). The mask inlet 110 may include one or more inhalation valves through which the wearer inhales the air.
The respiratory mask 100 further includes a mask outlet 112 through which a wearer's exhaled breath is emitted. The respiratory mask 100 further includes a valve 200 fitted on the mask outlet 112. The valve 200 is fluidly disposed in the mask outlet 112. In the illustrated embodiment of
The valve 200 further includes a valve flap 212 at least partially received within the valve housing 202. In some embodiments, the valve flap 212 is made of a deformable material. In some embodiments, the deformable material is an elastomer. Elastomers, which may be either thermoplastic elastomers or crosslinked rubbers, may include rubber materials such as polyisoprene, poly(styrene-butadiene) rubber, polybutadiene, butyl rubber, ethylene-propylene-diene rubber, ethylene-propylene rubber, nitrile rubber, polychloroprene rubber, chlorinated polyethylene rubber, chloro-sulphonated polyethylene rubber, polyacrylate elastomer, ethylene-acrylic rubber, fluorine containing elastomers, silicone rubber, polyurethane, epichlorohydrin rubber, propylene oxide rubber, polysulfide rubber, polyphosphazene rubber, and latex rubber, styrene-butadiene-styrene block copolymer elastomer, styrene-ethylene/butylene-styrene block copolymer elastomer, styrene-isoprene-styrene block copolymer elastomer, ultra-low density polyethylene elastomer, co-polyester ether elastomer, ethylene methyl acrylate elastomer ethylene vinyl acetate elastomer, and polyalphaolefin elastomers. Blends or mixtures of these materials may also be used.
The valve flap 212 may be constructed from materials that are deformed elastically over an actuation range of the valve flap 212. The valve flap 212 may be a monolayer flap constructed of only one material. Alternatively, the valve flap 212 may include two or more different materials dispersed throughout the bulk of the valve flap structure such that the composition of the valve flap 212 is uniform. The valve flap 212 may preferably be constructed from a material that has a modulus of elasticity that is preferably about 0.7 MPa or higher, more preferably about 0.8 MPa or higher, and potentially more preferably about 0.9 MPa or higher.
Referring again to
The valve 200 further includes a valve cage 222 coupled to the valve housing 202. In some embodiments, the valve cage 222 is coupled to the valve housing 202 via a push-fit connection arrangement. The valve cage 222 further includes an intermediate portion 224 extending along the longitudinal axis LA. For example, the valve housing 202 and the valve cage 222 may include complementary tongues and openings for providing a snap-fit coupling between the valve housing 202 and the valve cage 222.
The valve 200 further includes a central limiter 226 coupled to the valve cage 222 and extending towards the tubular projection 214 along the longitudinal axis LA. Specifically, the intermediate portion 224 of the valve cage 222 is coupled to the central limiter 226. Therefore, the central limiter 226 extends from the valve cage 222 along the longitudinal axis LA. The central limiter 226 is stationary within the valve 200. In some embodiments, the central limiter 226 is a component that is separate from the valve cage 222. In some embodiments, the central limiter 226 is an integral part of the valve cage 222. In that case, the valve cage 222 including the central limiter 226 may be a single piece molded component. In some embodiments, the central limiter 226 includes a solid cylindrical component made of a rigid material. In some embodiments, the central limiter 226 may be made of a material comprising glass-filled nylon. The central limiter 226 has a maximum width W1 (also illustrated in
The valve 200 further includes a cap 228 disposed on the valve flap 212 opposite to the valve seat 204. The cap 228 is engaged with the valve flap 212 and movable along the longitudinal axis LA. In some embodiments, the cap 228 is made of a rigid material having an elastic modulus greater than an elastic modulus of the deformable material of the valve flap 212. Therefore, in response to a given load, the valve flap 212 may be deformed and the cap 228 is not deformed.
The cap 228 further includes a frustoconical portion 234 extending from the annular shoulder 232 and a cylindrical portion 236 disposed at an end of the frustoconical portion 234. The frustoconical portion 234 is proximal to the tubular projection 214 and the cylindrical portion 236 is distal to the tubular projection 214. The cylindrical portion 236 engages with the valve flap 212. Specifically, the cylindrical portion 236 of the cap 228 engages with one annular step 216 from the plurality of annular steps 216 of the valve flap 212. Further, the one annular step 216 from the plurality of annular steps 216 is at least partially disposed radially inwards of the cylindrical portion 236 of the cap 228.
Referring again to
The valve flap 212 is disengaged from the valve seat 204 in a plurality of open configurations. The plurality of open configurations includes a first open configuration and a second open configuration.
With reference to
A linear movement of the valve flap 212 from the closed configuration to the first open configuration is depicted by an arrow M1 (shown in
Referring now to
The valve flap 212 at least partially deforms to transition from the first open configuration to the second open configuration. Specifically, as the elastic modulus of the rigid material of the cap 228 is greater than the elastic modulus of the deformable material of the valve flap 212, the engagement between the cap 228 and the valve flap 212 causes the valve flap 212 to at least partially deform in order to transition from the first open configuration to the second open configuration. A deformed state of the valve flap 212 is illustrated in
In response to the inlet pressure, at least a portion of the valve flap 212 deforms and moves non-linearly during the transition of the valve flap 212 from the first open configuration to the second open configuration. Specifically, the plurality of annular steps 216 of the valve flap 212 deform and move non-linearly during the transition of the valve flap 212 from the first open configuration to the second open configuration. A non-linear movement of at least the portion of the valve flap 212 from the first open configuration to the second open configuration is depicted by an arrow M2 (shown in
Due to the non-linear movement of the valve flap 212 from the first open configuration to the second open configuration, an excitation frequency of the valve 200 due to the inlet pressure changes and becomes different from a natural frequency of the valve 200.
As the valve 200 is not excited at its natural frequency, the fluttering in the valve 200 may be reduced. The reduced fluttering may provide an improved comfort to the wearer donning the respiratory mask 100. Moreover, in contrast to some conventional positive pressure respiratory masks, the respiratory mask 100 may not be annoying for the wearer because of the reduced fluttering in the valve 200 (i.e., the exhalation valve).
To achieve the reduced fluttering in the valve 200, only one valve flap (i.e., the valve flap 212) is being used in the valve 200 in contrast to sone conventional respiratory masks comprising two valve flaps for achieving the reduced fluttering in an exhalation valve. In other words, excessive vibrations may be damped in the valve 200 by using only one valve flap (i.e., the valve flap 212). Moreover, as compared to some conventional valves with two valve flaps, the use of only one valve flap in the valve 200 may reduce a cost of manufacturing the valve 200 and the respiratory mask 100.
In contrast to a conventional technique for reducing the fluttering in a valve by increasing a size of that valve, there is no requirement for increasing a size of any component in the valve 200 of the present disclosure. Therefore, while reducing the fluttering in the valve 200, compact design requirements of the respirator mask 100 may also be met. This may further reduce a complexity in designing the valve 200 for the respiratory mask 100.
As compared to another conventional technique for reducing the fluttering in a valve by adjusting characteristics of a biasing member, there is no need to adjust the characteristics of the biasing member 238 for reducing the fluttering in the valve 200 of the present disclosure. In other words, to achieve the reduced fluttering in the valve 200, there may be no requirement to have the biasing member 238 with a relatively lower strength or a relatively higher strength. Therefore, the valve 200 may have the reduced fluttering along with an adequate strength of the biasing member 238.
A pressure inside the respiratory mask 100 maintained by the demand valve (not shown) is also termed as “facepiece pressure”.
The plot 302 illustrates an inhale side 306 and an exhale side 304. In the graph 300, there are no sharp pressure peaks in the exhale side 304 of the plot 302. In other words, as the excitation frequency of the valve 200 (i.e., the exhalation valve) is different from the natural frequency, the plot 302 does not comprise any sharp pressure peak in the exhale side 304. Therefore, the reduced fluttering in the valve 200 depicted by absence of the sharp pressure peaks in the exhale side 304 is due to the fact that the excitation frequency of the valve 200 is different from its natural frequency.
Moreover, for the breathing rate at 25 strokes/min and 2 liters/stroke, the facepiece pressure (i.e., breathing resistance requirements) according to safety standards should be less than 7 mbar. As shown in the graph 300, the facepiece pressure is about 6 mbar and less than 7 mbar. For the breathing rate at 25 strokes/min and 2 liters/stroke, the reduced fluttering in the valve 200 along with conformation of the respiratory mask 100 to acceptable breathing resistance requirements may therefore provide an improved comfort to the wearer donning the respiratory mask 100.
The plot 402 illustrates an inhale side 406 and an exhale side 404. In the graph 400, there are no sharp pressure peaks in the exhale side 404 of the plot 402. In other words, as the excitation frequency of the valve 200 (i.e., the exhalation valve) is different from the natural frequency, the plot 402 does not comprise any sharp pressure peak in the exhale side 404. Therefore, the reduced fluttering in the valve 200 depicted by absence of the sharp pressure peaks in the exhale side 404 is due to the fact that the excitation frequency of the valve 200 is different from its natural frequency.
Moreover, for the breathing rate at 40 strokes/min and 2.5 liters/stroke, the facepiece pressure (i.e., breathing resistance requirements) according to safety standards should be less than 10 mbar. As shown in the graph 400, the facepiece pressure is about 9 mbar and less than 10 mbar. For the breathing rate at 40 strokes/min and 2.5 liters/stroke, the reduced fluttering in the valve 200 along with conformation of the respiratory mask 100 to acceptable breathing resistance requirements may therefore provide an improved comfort to the wearer donning the respiratory mask 100.
For the respiratory mask 100 (shown in
From the outcome of the results in Table 1, it was evident that the facepiece pressures (i.e., breathing resistance requirements) according to safety standards were acceptable in upward facing as well as in forward facing. For the breathing rate at 40 strokes/min and 2.5 liters/stroke, as the facepiece pressure was below 10 bar, the safety requirements according to EN136 were met. Further, for the breathing rate at 25 strokes/min and 2 liters/stroke, as the facepiece pressure was below 7 bar, the safety requirements according to EN136 were met.
Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the specification and claims are to be understood as being modified by the term “about”. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein.
Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations can be substituted for the specific embodiments shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this disclosure be limited only by the claims and the equivalents thereof.
This application claims priority from U.S. Provisional Application Ser. No. 63/303,213, filed Jan. 26, 2022, the disclosure of which is incorporated by reference in its entirety herein.
| Number | Date | Country | |
|---|---|---|---|
| 63303213 | Jan 2022 | US |
