Patent Description:
The treatment of obstructive sleep apnoea (OSA) by continuous positive airway pressure (CPAP) flow generator systems involves the continuous delivery of pressurized air to the airways of a human via a conduit and an interface (for example, a mask). Typically, the interface creates at least a substantial "seal" on or around the nose and/or the mouth. As the patient exhales, carbon dioxide gas can progressively collect in the delivery system. If left unchecked over a period of time, the accumulation of carbon dioxide can have adverse consequences.

<CIT> discloses a flow regulator for aerosol drug delivery device and methods.

One solution to the accumulation of carbon dioxide is to provide a washout vent. The washout vent can be provided within the mask system. The washout vent enables a flow of gas to be constantly exhausted to the atmosphere. The constant exhaust flow provides a mechanism to continually remove carbon dioxide, which counters the increase in carbon dioxide level.

The washout vents, while providing a mechanism for removing carbon dioxide, also have a number of trade-offs. State of art practice currently uses a hole/hole array of fixed dimensions. The fixed dimensions have the effect of enabling a bias flow of gas that increases as the CPAP pressure level increases. This increasing flow has implications for a number of parameters that affect the user.

The bias flow exiting through the washout vents typically creates disturbances for the patient and/or the patient's bed partner. The disturbances typically manifest in two forms: noise and draft. Changes in the bias flow rate, which are caused by changes in the CPAP pressure level, directly affect the magnitude of these disturbances. Thus, if a pressure oscillation exists within the system, then it is possible to produce an oscillating disturbance.

The flow and humidity source (for example, blower and humidifier) also can be impacted. Increasing the bias flow results in an increase in the physical dimension and power consumption to cater to the peak flow demand (that is, the sum of patient requirements and the maximum bias flow at peak pressure).

The creation of practical and not so practical solutions to this has been the subject of considerable development efforts. Yet, there is room for continued improvement in resolving the problems associated with reducing or eliminating the accumulation of carbon dioxide within a CPAP system.

A patient interface has a body portion sized and shaped to surround a nose and/or a mouth of a user and adapted to create at least a substantial seal with a face of the user. The patient interface also has a coupling that permits the patient interface to be coupled to a gas delivery system. The patient interface further has a vent that allows passage of gas from an interior of the body portion of a mask to an exterior of the body portion of the mask wherein a portion of the vent comprises means to regulate a flow of gas based on the applied pressure.

In some configurations, the means to regulate flow comprises an orifice constructed with varying wall section thickness.

In some configurations, the wall section thickness varies in the range of <NUM> to <NUM> microns.

In some configurations, the means to regulate flow operates in a pressure range of <NUM> cmH20 to <NUM> cmH20.

In some configurations, the means to regulate flow occurs without a deformable orifice entirely collapsing.

In some configurations, the means to regulate flow comprises one or more lobes formed by one or more surfaces and the means to regulate occurs without the one or more surfaces coming into contact with itself or themselves.

The present invention relates to a valve for use with a system for delivering CPAP therapy as claimed. The valve comprises a base and a membrane. The membrane has a first end defining an inlet opening. The base has a second end defining an outlet opening. The first end of the membrane has at least one concave portion and at least one convex portion and the first end of the membrane is configured to collapse inwardly to vary a flow path size in response to changes in pressure acting on the membrane.

In some configurations, the at least one concave portion and the at least one convex portion are defined by an inflection on an outer surface of the membrane.

In some configurations, the at least one concave portion and the at least one convex portion are defined by an inflection on an inner surface of the membrane.

In some configurations, the at least one concave portion and the at least one convex portion are defined by a change in membrane thickness.

In some configurations, the at least one concave portion and the at least one convex portion are defined by a change in membrane thickness and an inflection on at least one of an inner surface and an outer surface of the membrane.

In some configurations, the at least one concave portion comprises a lobe and the at least one convex portion comprises a bridging portion.

In some configurations, the valve comprises only two lobes and only two bridging portions.

In some configurations, the valve comprises only three lobes and only three bridging portions.

In some configurations, the valve comprises only four lobes and only four bridging portions.

In some configurations, the valve comprises a triangular base.

In some configurations, the valve comprises a circular base.

In some configurations, the base can have a first geometric shape and the inlet opening defined by the membrane can have a second geometric shape. In some such configurations, the first geometric shape is the same as the second geometric shape. In some such configuration, the first geometric shape is triangular and the second geometric shape is triangular. In some such configurations, the first geometric shape is different from the second geometric shape. In some such configurations, the first geometric shape is circular and the second geometric shape is triangular.

In some configurations, the transition between the base and the inlet opening defined by the membrane is non-linear. In some such configurations, the transition is arcuate. In some configurations, the membrane can have a first portion that transitions in a non-linear manner away from the base but symmetrically to the base and a second portion that transitions from the first portion in a non-linear manner to the inlet but non-symmetrically to the base.

The valve further comprises a splint that extends into a mouth defined by the first end of the membrane.

The splint extends from the first end of the membrane to the second end of the base.

In some configurations, the valve further comprises a bias material disposed at the second end of the base.

In some configurations, the bias material comprises a plurality of bias flow holes.

In some configurations, the bias material comprises a diffuser.

In some configurations, a valve array comprises at least two of the valves.

In some configurations, the at least two valves comprise two rows of valves.

In some configurations, the two rows of valves are nested together.

In some configurations, the two rows have valves disposed side by side.

In some configurations, the at least two valves comprise a predetermined pattern of valves.

In some configurations, the valve array is combined with a mask, the valve array being mounted to the mask.

In some configurations, the valve array is disposed on a seal housing of the mask.

In some configurations, the valve array is disposed on a seal of the mask.

In some configurations, the valve array is disposed on a frame of the mask.

In some configurations, the mask comprises an exhaust conduit and the valve array is disposed in the exhaust conduit.

In some configurations, the valve array is combined with an elbow, the valve array being mounted to the elbow.

In some configurations, the valve array is mounted to a cover that is associated with the elbow.

In some configurations, the cover is removable from the elbow.

In some configurations, the valve array is combined with a swivel, the valve array being mounted to the swivel.

The following describes some practical options to improve current designs.

These and other features, aspects and advantages of the present technology will now be described with reference to the drawings of several preferred embodiments, which embodiments are intended to illustrate and not to limit the invention, and in which figures:.

As described above, certain features, aspects and advantages of the present technology relate to providing a bias flow that has significant less variance in flow rate over a normal operating pressure range for CPAP systems.

<FIG> shows the performance of a conventional bias hole array over a variety of CPAP pressure levels. It can be seen that the bias flow increases by approximately <NUM>% (that is, from about <NUM>/min to about <NUM>/min) as the pressure is increased from 4cmH20 to 20cmH20. <FIG> shows the performance of one embodiment of a constant bias flow control system arranged and configured in accordance with certain features, aspects and advantages of the present technology. The illustrated performance is under varying CPAP levels. It can be seen that the bias flow increases by approximately <NUM>% (that is, from about <NUM>/min to about <NUM>/min) as the pressure is increased from 4cmH20 to 20cmH20.

As shown by comparing <FIG>, the constant bias flow control systems that are arranged and configured in accordance with certain features, aspects and advantages of the present technology enable enhanced control over the sound intensity and/or the drafts created as the bias flow exits the CPAP system. Furthermore, the illustrated constant bias flow control systems reduce the flow overhead required in the flow source/CPAP source to accommodate the phenomenon shown in <FIG>. Because the flow source/CPAP must make up for the ever increasing flow that simply exits through the bias flow vents, the flow source/CPAP size and energy requirement of the flow source/CPAP source must be increased relative to an ideally sized unit.

<FIG> illustrates a bias flow control valve <NUM> that is arranged and configured in accordance with certain features, aspects and advantages of the present technology. The bias flow control valve <NUM> advantageously alters the flow opening over a range of pressures. In other words, as the pressure in the system increases, an outlet for gases defined by the bias flow control valve <NUM> constricts, thereby acting to reduce the bias flow as compared to prior bias flow constructions.

In some configurations, the valve <NUM> may be formed of silicone rubber (or other suitable thermoplastic elastomers). Silicone contains hydrophobic characteristics that are beneficial for reducing or eliminating condensation build up in or on the valve <NUM> during use. Any other suitable material or combination of materials can be used. In some configurations, a less flexible portion of the valve <NUM> may be formed of a first material and a more flexible portion of the valve <NUM> may be formed of a second, less resilient, material when compared to the first material.

The illustrated bias flow control valve <NUM> comprises a base <NUM>. The base <NUM> can include a flange or a rim. In the arrangement of <FIG>, for example, the base <NUM> is ring-like and can define an outer ring. In other words, in the arrangement of <FIG>, the base is generally circular in configuration. As shown in <FIG>, the base <NUM> does not have to be circular but can have any other desired shape. In some configurations, the base <NUM> can be a smooth, non-circular or non-cylindrical shape, such as the triangular shape of <FIG>. The shape of the base can vary from configuration to configuration. By varying the shape of the base, different geometries of surrounding structures can be accommodated. In some configurations, multiple valves are used and, by having the base <NUM> have a triangular shape, for example but without limitation, an increased number of valves <NUM> can be mounted over a predetermined surface area. The shape of the base <NUM> can vary between two or more valves in a single multi-valve configuration or the shape of the base <NUM> can be consistent between all valves in a single multi-valve configuration.

The base <NUM> facilitates coupling or connection to the component to which the bias flow control valve <NUM> is mounted. Any suitable configuration can be used keeping in mind a desire to join the valve <NUM> to the component in or to which it is mounted. In some configurations, the valve <NUM> is not removable from the component in or to which it is mounted without significant destruction to the valve <NUM> and/or the component. In some such configurations, the base <NUM> forms an integral portion with a surrounding structure.

A membrane <NUM> can be connected to the base <NUM> in any suitable manner. In some configurations, the membrane <NUM> can be integrally formed with the base <NUM>. The membrane <NUM> is relatively more flexible than the base <NUM>. With reference to <FIG>, in the illustrated configuration, an outlet <NUM> can be defined by the base <NUM> and an inlet <NUM> can be defined by the membrane <NUM>. The inlet <NUM> and the outlet <NUM> are axially offset from each other in the direction of flow (that is, along the central axis of the valve <NUM>). In some configurations, the inlet <NUM> and the outlet <NUM> can be axially offset by different distances at different operating pressures. In some configurations, the inlet <NUM> moves toward the outlet <NUM> as pressure within the system increases.

In some configurations, such as shown in <FIG>, the base <NUM> and the inlet <NUM> defined by the membrane <NUM> can have different geometries (for example, a circular base <NUM> with a triangular inlet <NUM>). In some configurations, such as shown in <FIG>, the base <NUM> and the inlet <NUM> can have similar geometries (for example, a triangular base <NUM> and a triangular inlet <NUM>). In some configurations, the transition between the base <NUM> and the inlet <NUM> is non-linear (that is, even when transitioning from a triangular base to a triangular opening, the wall has an arc in cross-section instead of a linear progression). Such a non-linear configuration, for example, can be seen in <FIG>, <FIG>, and <FIG>. In some configurations, the membrane <NUM> can have a first portion that transitions in a non-linear manner away from the base <NUM> but symmetrically to the base and a second portion that transitions from the first portion in a non-linear manner to the inlet <NUM> but non-symmetrically to the base.

In terms of flow path size, the inlet <NUM> is a first size in a first condition and the inlet <NUM> is smaller in a second condition. That is, under a first operating pressure in the system, the inlet <NUM> can have a first size and, under a second operating pressure in the system that is higher than the first operating pressure, the inlet <NUM> can have a second size that is smaller than the first size. In other words, the outlet <NUM> can have a first inner perimeter length and the inlet <NUM> can be defined by a rim <NUM> formed on the membrane <NUM> with the inlet <NUM> having a second inner perimeter length. The second inner perimeter length can be less than the first inner perimeter length. In some configurations, the inlet has an opening with three lobes <NUM> and an opening area of <NUM> mm2. In such configurations, the valve <NUM> can be used alone as a single valve and transmit an initial flow of <NUM>/min at a CPAP pressure of <NUM> cmH2O.

As shown in <FIG>, the inlet <NUM> is disposed into the direction from which the flow originates. Thus, the membrane <NUM> is positioned on the higher pressure side of the base <NUM> in the illustrated configuration. As shown in <FIG>, at least a portion of the membrane <NUM> can deflect with the application of pressure (for example, the dotted lines show the deflection of the valve <NUM>). The deflection of the membrane <NUM> serves to constrict at least a portion of the flow passage through the valve. In the illustrated configuration, the deflection of the membrane <NUM> serves to constrict the inlet <NUM> to the valve <NUM>. In some configurations, the membrane <NUM> deflects in two directions (that is, one or more of the walls surrounding the opening of the inlet <NUM> deflect inwardly to decrease the flow path through the opening and the inlet <NUM> moves axially toward the outlet).

As shown in <FIG>, the rim <NUM> can define two or more lobes <NUM>. Each lobe <NUM> can be connected to an adjacent lobe <NUM> with a bridging portion <NUM>. The lobes present themselves as concave regions (that is, concave with respect to the center axis of the passageway defined through the valve <NUM>). The bridging portions <NUM> can present themselves as convex regions (that is, convex with respect to the center axis of the passageway defined through the valve <NUM>).

Any number of lobes can be used. More than one lobe has been found to be easier to design and manufacture that a single lobe in order to get the desired repeatability and controllable closing of the opening. <FIG> shows a three lobe configuration. Each of <FIG> and <FIG> shows a two lobe configuration. <FIG> shows a four lobe configuration. From a stability standpoint and an ease of design and manufacture standpoint, the three lobe configuration has been a favored configuration.

In some configurations, the lobes <NUM> can be symmetrically disposed about the central axis CA. In some configurations, the apex of each lobe <NUM> can be equidistant from the central axis CA. In other words, the apex of each lobe <NUM> is spaced from the central axis CA the same distance at the apex of each of the other lobes <NUM>. In some configurations, the apex of each lobe <NUM> can be equidistant from the central axis CA with respect to the apex of any diametrically opposed lobe <NUM>. In some configurations, the apex of each lobe <NUM> is equidistant from the central axis CA and an included angle between each of the lobes is equal for all of the lobes <NUM>. In other words, the lobes <NUM> are symmetrically spaced about the central axis CA. In some configurations, the lobes <NUM> are not all symmetrically spaced about the central axis CA but are spaced in one or more symmetrical patterns. Other configurations also are possible.

In some configurations, an inner member <NUM> can be positioned within the valve <NUM>. The inner member <NUM> can be used with any valve configuration described herein. The inner member <NUM> can be positioned in the region of the inlet <NUM>. The inner member <NUM> can be a rigid tube in some configurations. The inner member <NUM> provides a minimum flow passage such that, if the membrane <NUM> were to collapse fully around the inner member <NUM>, the inner member would maintain a flow path. As such, in some configurations, the inner member <NUM> is a single tube with an inner lumen <NUM>. In some configurations, the inner member <NUM> is a plurality of posts that maintain a flow path through the valve <NUM> by reducing or eliminating the likelihood of a total closure of the valve <NUM>. In effect, the inner member <NUM> can be any component that acts as a splint to hold open at least a portion of the valve <NUM> when the valve is in an otherwise closed position. The opening that is preserved can be related to a desired flow at the maximum operating pressure of the CPAP machine or other flow generator.

With reference to <FIG>, the illustrated inner member <NUM> is mounted to a support structure <NUM>. The support structure <NUM> can support the inner member <NUM> in position without significantly impacting flow through the valve <NUM>. The illustrated support structure <NUM> comprises one or more cross members <NUM>. In the illustrated configuration, the inner member <NUM> can extend from the inlet <NUM> to the outlet <NUM> and can be supported at any desired location along the length of the inner member <NUM>. In some configurations, the support structure <NUM> can be positioned within the base <NUM>. In some configurations, the support structure <NUM> can be positioned adjacent to the outlet <NUM>.

One or more of the adjacent regions of the valve can close off against an outer surface of the inner member <NUM> as the flow generator increases the pressure. Through the use of the inner member <NUM>, a flow path through the valve <NUM> can be maintained. Such configurations can reduce or eliminate the likelihood of the valve <NUM> inverting, closing off completely at high pressures or overly limiting flow at higher pressures, which may occur, for example, when a user coughs. In some configurations, the inner member <NUM> can be formed of the same material as the rest of the valve <NUM>. In some configurations, the inner member <NUM> can be formed of different materials relative to the rest of the valve <NUM>. In some configurations, the inner member <NUM> can have a wall thickness of the same material as used for the membrane but with a wall thickness sufficient to maintain an open flow path through the membrane. In some configurations, the inner member <NUM> can be formed of the same material used to form the base <NUM>.

In configurations now featuring the inner member <NUM>, the shape and/or the varying thicknesses and/or stiffnesses surrounding the opening defined by the inlet <NUM> can help reduce or eliminate the likelihood of the valve <NUM> entirely collapsing and can help reduce or eliminate the likelihood of the valve <NUM> sticking shut in use. In constructions without the inner member <NUM> as well as those with the inner member <NUM>, the wall thickness can change around a given cross section (see <FIG>); the wall thickness also can change along the principal axis of the valve <NUM> (see <FIG>). The illustrated changes in wall thickness help to provide a smooth constricting mechanism across the operating pressure range for treating sleep apnoea or other respiratory care patents.

With reference again to <FIG>, in some configurations, the wall thickness of the membrane can be varied at and/or near the rim <NUM>. In some configurations, the wall thickness of the membrane can be varied at the rim <NUM> and axially along at least a portion of the membrane in the direction of the outlet outer rim <NUM>. Such a wall thickness variance is shown in the cross section of <FIG>, where the wall tapers from the base <NUM> to the inlet <NUM>. As also illustrated in <FIG> and <FIG>, for example, the wall defined by the membrane <NUM> can be relatively thicker in the lobes <NUM> and relatively thinner in the bridging portions <NUM>. Such a configuration increases the likelihood of controlled collapsing of the inlet <NUM> when pressure is applied to the outer wall of the membrane <NUM>.

If the thickness in the bridging portions <NUM> is too thick, then the valve <NUM> may be less deformable and may not close enough and, if the thickness in the bridging portions <NUM> is too thin, then the valve <NUM> may be too deformable and may close too much. In some silicone rubber configurations, the wall sections of the constructed valve <NUM> can be in the range of <NUM> to <NUM> microns for the relatively thicker portions and <NUM> to <NUM> microns for the relatively thinner portions. In the configuration of <FIG>, the apexes of the lobes <NUM> can have a thickness of <NUM> microns while the middle region of the bridging portions <NUM> can have a thickness of <NUM> microns. A transition between the thicker lobes <NUM> and the thinner portion of the bridging portion <NUM> (that is, a transition between the concave lobes <NUM> and the convex bridging portions <NUM>) can assist in resisting collapse of the valve <NUM>. If the outer radius of the lobes <NUM> is reduced from <NUM> to <NUM> or <NUM>, the valve <NUM> of <FIG> collapses too easily. The centres of the inner and outer radii of the concave portions <NUM> in the valve <NUM> of <FIG> are offset by <NUM> along radial axes that extend from the centre of the opening.

As illustrated in, for example, <FIG>, the wall of the membrane <NUM> that defines the lobes <NUM> and the bridging portion <NUM> can have a uniform thickness about the entire periphery of the rim <NUM>. In some such configurations, the geometry can be tuned to obtain the desired collapsing characteristics. In some such configurations, the material can be varied to provide a stiffer portion in the lobes <NUM> and a more flexible portion in the bridging portions <NUM>. Any other suitable combination of these or any other suitable configuration can be used to obtain a valve that at least partially collapses upon itself as described herein.

The lobes <NUM> provide stiffness to reduce or eliminate the likelihood of the valve inverting under high pressures. In general, however, the stiffness of the membrane <NUM> is defined by the thickness in the lobes <NUM>, the profile of the wall, the height of the valve <NUM> and the properties of the material used to make the valve. As shown in <FIG>, the valve <NUM> deforms in a way that narrows the flow passage and, thereby, reduces the level of flow that can be passed through the valve <NUM>. In <FIG>, the valve is shown with no operating pressure (that is, <NUM> cmH2O) while, in <FIG>, for example, the valve is shown under a pressure of greater than <NUM> cmH2O. As shown in <FIG>, under the application of pressure to the membrane <NUM>, the thinned wall section deforms, which results in changes to the flow passage defined through the lobe <NUM> cross sectional area changing, which in turn changes the flow rate that is possible through the flow passage defined through the lobe <NUM> based on the pressure differential that exists across the valve <NUM>. By varying the relative portions of the thick to thin (or more stiff to more flexible), the performance of the valve <NUM> can be tuned for specific operating pressure ranges. In some configurations, one or more deformable orifice does not entirely collapse within the range of normal operating pressures. In some configurations, each lobe can include one or more surface and the one or more surfaces do not come into contact with itself or themselves within the range of normal operating pressures. Thus, one or more of the lobes, the bridging portions and the varied thicknesses, at least in part, can define means to regulate a flow of gas based on the applied pressure.

As shown in <FIG>, using multiple small valves <NUM> can approximate the flow characteristics of a single larger valve, but using multiple small valves <NUM> can reduce the noise relative to using a single valve <NUM> having the same throughput. This is because the multiple small flow restrictions will result in small pressure drops across each valve resulting in less turbulence and less noise generation. This is demonstrated in the graphical depiction of <FIG>. As illustrated, within increasing pressures, a single large valve arranged and configured in accordance with certain features, aspects and advantages of the present technology is demonstratively louder than two small valves. Moreover, the data shows that the increase in loudness for two smaller valves increases significantly less over the illustrated larger valve.

With reference now to <FIG>, any configuration of the valve <NUM> described above can be used in a valve array <NUM>. The valves <NUM> used in an array can be miniaturized relative to a single valve <NUM>. To be clear, the valves <NUM> that make up the valve array <NUM> can be uniform in configuration or can be assorted in configuration. In some valve arrays <NUM>, the valves <NUM> are configured to have the same operating characteristics uniformly across the field of the array <NUM>. In some valve arrays <NUM>, one or more of the valves <NUM> may be configured to behave differently relative to others at the same operating pressures. In some configurations, twenty valves will be used to provide an approximate cross sectional area of about <NUM> mm2. Other numbers of valves can be used and other cross sectional areas can be used.

With reference to <FIG>, a multivalve component <NUM> is illustrated. The multivalve component <NUM> comprises an array <NUM> of valves <NUM>. The valves <NUM> are configured as described above. A common base <NUM> connects the valves <NUM> in the illustrated configuration. In some configurations, the common base <NUM> can be formed in multiple pieces that are connected or interconnected. In some configurations, the base <NUM> of each valve can be received within a receptacle or opening of a plate that serves as the common base. Any other configurations can be used.

With continued reference to <FIG>, the valves <NUM> in the illustrated configuration are spaced in a symmetrical pattern. The rotational orientation of the valves <NUM> is such that two of the valves <NUM> are rotated <NUM> degrees relative to two of the other valves <NUM>. In other words, the apex of the lobes <NUM> of two of the valves <NUM> points toward the apex of the lobes <NUM> of the other two of the valves <NUM>. In some configurations, the four valves <NUM> can be orientated such that one of the lobes <NUM> of each of the valves <NUM> points toward a center of the multivalve component. Other orientations of the valves <NUM> also are possible.

With reference now to <FIG>, the illustrated array <NUM> of valves <NUM> is shown on a multivalve insert <NUM>. The multivalve insert <NUM> can comprise any desired number of valves <NUM> to provide a desired level of flow. In the illustrated configuration, the multivalve insert <NUM> comprises twenty valves <NUM>. The valves are arranged in four rows and five columns in the illustrated configuration. In the illustrated configuration, the valves <NUM> also are oriented in a single direction. Other configurations are possible.

The multivalve insert <NUM> can be formed in any suitable manner of any suitable material. For example, in some configurations, the multivalve insert <NUM> can be formed of a single material. In some such configurations, the entire multivalve insert <NUM> can be formed of a material such as silicone or any suitable thermoplastic elastomer. The configuration of <FIG> is completely formed of a single such material.

With reference to <FIG>, the illustrated multivalve insert <NUM> is the same as the multivalve insert <NUM> illustrated in <FIG> except the multivalve insert <NUM> in <FIG> comprises a substrate material <NUM>. The substrate material <NUM> can be the same material used to form the valves <NUM> or can be a different material. In some configurations, the substrate material <NUM> provides a rigid base for the valves <NUM> of the multivalve insert <NUM>.

<FIG> schematically illustrates another multivalve component <NUM>. The multivalve component <NUM> illustrated in <FIG> comprises a plurality of rows of valves <NUM>. The valves <NUM> have one row with a first orientation and a second row with an opposite orientation; the two adjacent rows of valves <NUM> are nested. By nesting the valves <NUM>, a greater valve density can be obtained.

With reference now to <FIG>, a further valve array <NUM> on a multivalve component <NUM> is illustrated. The valves <NUM> in the illustrated configuration are arranged in a pattern of rows having unequal numbers of valves <NUM>. The illustrated configuration features three rows of valves <NUM> with the center row having more valves <NUM> than the outer rows. In particular, the center row has one additional valve <NUM> at each end of the row.

<FIG> illustrates a valve array <NUM> on a multivalve component <NUM>. The valves <NUM> in the valve array <NUM> have a non-linear layout. The valves <NUM> may be arranged in a manner that can be predetermined by the designer.

<FIG> illustrates another valve array <NUM> on a multivalve component <NUM>. In the illustrated configuration, the valves <NUM> are arranged in different rows. The center two rows have nine valves <NUM> arranged side-by-side. Each of the center rows is flanked by an intermediate row that is in turn flanked by an outside row. Each intermediate row includes seven valves <NUM>. Each outside row includes three valves <NUM>. The valves <NUM> in the outside rows can be aligned with the valves <NUM> in the center rows while the valves <NUM> in the intermediate rows can be offset from the valves in the center rows and the outside rows.

<FIG> shows a further valve array <NUM> on a multivalve component <NUM>. In the illustrated configuration, the valves <NUM> form two staggered lines. The valves <NUM> can be used to like the periphery of a component of a mask system or the like.

Any of the valve configurations described herein can be incorporated into a breathing mask or related component. For example, the valve arrays <NUM> can be incorporated into a nasal mask, a pillows mask, a full face mask, a conduit, an elbow, or the like. In addition, it is possible to integrate traditional bias flow holes into the valve arrays such that the bias flow holes and the valves <NUM> are used together in a single array or component. In some configurations, a line of valves can be flanked by a row of bias flow holes. In some configurations, a line can contain valves and bias flow holes. Any other suitable configuration can be used.

In the following discussion, the term "valve" will include "valve array" unless otherwise apparent. The bias flow control valve <NUM> can be positioned in any suitable location keeping in mind a desire to allow evacuation of carbon dioxide from within the system where the carbon dioxide is introduced through exhalation. The valve <NUM> preferably is not the only flow path between the patient and the flow generator (for example, CPAP). In other words, the air flow must have a path to travel from the flow generator to the patient without passing through the valve <NUM>. Without the alternative flow path, the pressure drop through the valve <NUM> would mean that the patient was not receiving the prescribed pressure. The valve <NUM> can be placed anywhere in the system that a bias vent arrangement could be placed. In some configurations, the valve <NUM> can be placed in front of or behind or as a replacement for the bias vent arrangement. Further, the valve <NUM> can be placed so that the axis of the valve <NUM> is perpendicular to the surface or can be on an angle to the surface in order to better provide directional control to the flow emanating from the valve <NUM>.

In some configurations, the valve <NUM> can be positioned between the patient and the bias flow holes. In some configurations, however, such a positioning may lead to increased noise and/or decreased or impaired valve performance. For example, a system with a larger pressure drop across the bias flow holes (for example, a smaller cross sectional area of the holes) than across the valve <NUM> could decrease the performance of the valve <NUM>. To address such an issue, the valve <NUM> could be provided with less stiffness. In some configurations, a system with a pressure drop that is higher across the valve than the bias flow holes could result in increased noise generation as the air jets onto the surface and through the bias flow holes. This can be reduced by having a larger chamber between the bias flow holes and the valve and by minimizing the pressure drops between the two parts. In some configuration, this can be addressed by providing a hollow frame or shroud through which venting can occur.

With reference to <FIG>, the valve <NUM> can be placed in line with one or more bias flow holes <NUM>. By positioning the valve <NUM> in line with the bias flow holes <NUM>, the holes <NUM> can quiet the sound of a larger valve <NUM>. This is particularly advantageous because a larger valve <NUM> is easier to manufacture than the smaller valves used in the valve arrays <NUM> discussed above. It is possible to place a valve array <NUM> in line with the bias flow holes <NUM> as well. It also is possible to use a diffuser in place of or further in line with the bias flow holes <NUM>.

In some configurations, the bias flow control valve <NUM> can be positioned on an interface. In some configurations, the bias flow control valve <NUM> can be positioned on a mask. In some configurations, the bias flow control valve <NUM> can be positioned on a connector that is positioned between a conduit and a mask. In some configurations, the bias flow control valve <NUM> can be positioned on a conduit that connects to the mask. The bias flow control valve <NUM> can be used with any suitable mask configuration (not shown). The mask can include a body portion sized and shaped to surround the nose and/or mouth of the user. The mask can be adapted to create at least a substantial seal with the user's face. The body portion of the mask can have an interior and an exterior. The mask can include a coupling that permits the patient interface to be coupled to the gas delivery system. The bias flow control valve <NUM> allows the passage of gas from the interior of the body portion of the mask to the exterior of the body portion of a mask.

With reference now to <FIG>, the valve <NUM> can be mounted to a connector structure, such as an elbow <NUM>. As illustrated, the elbow <NUM> can include an opening <NUM>. The opening can receive at least a portion of the valve <NUM>. In some configurations, the valve <NUM> is mounted to a cover <NUM>. The cover <NUM> can be permanently secured or removably connected to the elbow <NUM>. In some configurations, the valve <NUM> and the cover <NUM> can be connected by overmoulding or the like. In some configurations, a bias material <NUM> can be mounted to the cover <NUM> or otherwise be positioned such that flow through the valve <NUM> also flows through the bias material <NUM>. The bias material can be a group of bias flow holes or a diffuser scrim material or the like. While the illustrated configuration is on an elbow, a similar configuration can be used elsewhere on the mask, on the conduit or on a connector, for example.

With reference now to <FIG>, a mask <NUM> is illustrated that integrates a valve array <NUM> that is arranged and configured as described above. The mask <NUM> generally comprises a seal housing <NUM> and a cushioning seal <NUM>.

In the illustrated configuration, the seal housing <NUM> comprises a multivalve insert <NUM> such as that described above, for example but without limitation. The multivalve insert <NUM> can be removable in some configurations (for example, clipped into position). The multivalve insert <NUM> can be moulded into the mask <NUM> (for example, moulded into the seal housing <NUM>). As described above, the valves <NUM> can be supported by a flexible base or can be supported by a more rigid substrate material. In some configurations, instead of the multivalve insert <NUM> featuring multiple valves <NUM>, a single valve <NUM> can be used. In some configurations, instead of one valve array <NUM>, more than one valve array <NUM> can be used (that is, more than one group of valves).

In the event that no biasing material is used such that the valve <NUM> or valves <NUM> vent directly to atmosphere, then multiple valves <NUM> are preferred. In the illustrated configuration, however, a plenum chamber <NUM> is defined between the multivalve insert <NUM> and a biasing material <NUM>. The plenum chamber <NUM> can be larger than illustrated in some configuration. In addition, it is possible to include a hollow frame that the valve or valve array vents into.

With reference to <FIG>, a graphical depiction is provided that shows various flows at various pressures for embodiments of the mask <NUM> that include: (<NUM>) a large valve with bias flow holes; (<NUM>) a large valve; (<NUM>) bias flow holes; and (<NUM>) a large valve with a diffuser material. These configurations are illustrated in <FIG>. As illustrated in the graphical depiction, having the bias flow holes changes the performance of the mask <NUM>. The maximum flow rate is approximately the same as when there are no holes in line with the valve, but the flow does not drop away until a higher pressure is applied. Having the bias flow holes in line with the valve would therefore be improved by changing the valve configuration, but does not necessarily result in a reduction of performance of the mask <NUM>.

With reference to <FIG>, a graphical depiction is provided that shows various loudness data points at various pressures for the same embodiments of the mask <NUM> as discussed directly above. As can be seen, in order to reduce the noise of the valve <NUM>, it is best to incorporate a diffuser material after the valve.

<FIG> illustrates another configuration in which the multivalve insert <NUM> is positioned on the elbow <NUM>. The configuration can be similar to that shown in <FIG> and can incorporate the same elements: the valves <NUM>, the valve array <NUM>, the multivalve insert <NUM>, the bias material <NUM>, and the plenum chamber <NUM>. In the illustrated configuration, the elbow <NUM> comprises the multivalve insert <NUM>, such as that described above, for example but without limitation. The multivalve insert <NUM> can be removable in some configurations (for example, clipped into position). The multivalve insert <NUM> can be moulded into the elbow <NUM>. As described above, the valves <NUM> can be supported by a flexible base or can be supported by a more rigid substrate material. In some configurations, instead of the multivalve insert <NUM> featuring multiple valves <NUM>, a single valve <NUM> can be used. In some configurations, instead of one valve array <NUM>, more than one valve array <NUM> can be used (that is, more than one group of valves).

In the event that no biasing material is used, such that the valve <NUM> or valves <NUM> vent directly to atmosphere, then multiple valves <NUM> are preferred. In the illustrated configuration, however, a plenum chamber (not shown but similar to that of the mask embodiment) is defined between the multivalve insert <NUM> and a biasing material <NUM>. It is possible to include a hollow frame that the valve or valve array vents into.

<FIG> illustrates a configuration in which a secondary exhaust tube <NUM> can be provided to the mask <NUM>. The secondary exhaust tube <NUM> can include a valve <NUM> at the end of the exhaust tube <NUM>. The valve <NUM> can restrict exhaust flow. The secondary exhaust tube <NUM> with the valve <NUM> provides a benefit of venting remotely from the user. In such remote locations, the noise of the valve is perceived to be less of a concern, for example. In some configurations, the secondary exhaust tube <NUM> can travel along at least a portion of a supply tube <NUM>. In some configurations, the exhaust tube <NUM> can travel alongside of the intake tube <NUM>. In some configuration, the exhaust tube <NUM> can be positioned coaxially within the intake tube <NUM>. In some configurations, the exhaust tube <NUM> can surround at least a portion of the intake tube <NUM>. Other configurations are possible.

With reference to <FIG>, a further configuration for a mask <NUM> is shown. The mask <NUM> includes a frame <NUM> to which a mask seal <NUM> can be secured. The mask frame <NUM> can include a ring <NUM>. The ring <NUM> can at least partially encircle a socket <NUM> that receives an elbow, connector, conduit or the like. The ring can be provided with one or more valves <NUM>. In some configurations, several small valves <NUM> can be disposed around the ring <NUM>. By separating the valves, interference between the air flowing out of adjacent valves can be reduced, which thereby reduces turbulence and noise. In some configurations, the valves can be integrally formed with the ring <NUM> or other mounting structure. In some configurations, the ring <NUM> or other mounting structure can be integrally formed (for example, overmoulded) with the frame <NUM>. In some configurations, the ring or other mounting structure can be removably attached to the frame <NUM>. In some configurations, the ring or other mounting structure can be separately formed from the frame <NUM> and can be secured to the frame in any suitable manner.

With reference to <FIG>, a configuration of the mask <NUM> is shown in which the valves <NUM> are positioned on the mask seal <NUM>. Because the mask seal <NUM> generally is formed of silicone or another similar material, the valves <NUM> can be integrated into the mask seal <NUM> and thereby reduce manufacturing steps. In some embodiments, the valves <NUM> can be grouped together on particular regions of the mask seal <NUM>. In some configurations, there may be a group of valves <NUM> on each lateral side of the mask seal <NUM>. In some configurations, there may be a group of valves <NUM> on the top of the mask seal <NUM>. In some configurations, there may be a group of valves <NUM> on the bottom of the mask seal <NUM>. Any combination of these groups also can be used. In some configurations, each of the valves <NUM> in any single group may be aligned in a single direction such that the flow from the valves <NUM> is in the same direction. In addition, aligning groups of valves advantageously simplifies manufacturing by providing a single draw plane for simplified moulding.

Claim 1:
A valve (<NUM>) for use with system for delivering CPAP therapy, the valve (<NUM>) comprising a base (<NUM>) and a membrane (<NUM>), the membrane (<NUM>) having a first end defining an inlet (<NUM>) opening, the base (<NUM>) having a second end defining an outlet (<NUM>) opening, the first end of the membrane (<NUM>) having at least one concave portion and at least one convex portion and the first end of the membrane (<NUM>) being configured to collapse inwardly to vary a flow path size in response to changes in pressure acting on the membrane (<NUM>) wherein the valve (<NUM>) further comprises a splint to hold open at least a portion of the valve (<NUM>) when the valve (<NUM>) is in an otherwise closed position, the splint extending into the inlet (<NUM>) defined by the first end of the membrane (<NUM>), the splint extending from the first end of the membrane (<NUM>) to the second end of the base (<NUM>).