Pressure relief device and method for opening an airway

Abstract

The apparatus and method are for regulating the vacuum level within a chamber apparatus having a housing enclosing an interior chamber volume through the use of one or more pressure relief valve elements that open at a predetermined vacuum level to create an opening through the housing and close at a lower, second, predetermined vacuum level within the chamber volume.

Description

[Technical field]

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 159,355, filed March 10, 2021, which is incorporated by reference in its entirety, including all tables, figures, and claims to which priority is claimed. [Background technology]

[0002] The following discussion of the background of the invention is provided merely to aid the reader in understanding the invention and is not admitted to describing or constituting prior art to the invention.

[0003] The application of external negative pressure to a patient for palliative or therapeutic purposes is well established in the medical field.

[0004] US Patent Nos. 5,343,878, 7,182,082, and 7,762,263 describe various devices that are intended to apply negative pressure externally to the outer surface of a patient's neck. The therapeutic devices are generally provided with a surface configured to encapsulate the outer region of the pharynx (as used herein, the term "pharynx" refers to the anterior portion of the neck extending laterally from approximately the chin to the top of the sternum and to a point posterior to the external jugular vein), which overlies a portion of the upper airway. In certain embodiments, the devices may provide a chamber (e.g., a hollow space filled with air molecules) between the inner surface of the chamber and the pharynx. The therapeutic devices are operably connected to an air pump configured to create a partial vacuum within the chamber. Applying a therapeutic level of negative pressure within the chamber induces movements that maintain the patency of the upper airway by drawing the soft tissues of the neck region outward, which may alleviate conditions such as snoring, sleep apnea, and complete or partial airway collapse.

[0005] Topical negative pressure ("TNP") therapy, also called continuous negative pressure suction therapy, negative pressure wound therapy, or reduced pressure wound therapy, is widely recognized as a beneficial mechanism for improving the healing rate of wounds. Such therapy is applicable to a wide range of wounds, such as incisions, open wounds, and abdominal puncture wounds. TNP therapy aids in wound closure and healing by reducing tissue edema, promoting blood flow, stimulating granulation tissue formation, removing excess exudate, and may reduce bacterial load, thereby reducing wound infection. Furthermore, TNP therapy allows for less external disturbance of the wound, promoting more rapid healing. Devices for negative pressure treatment of wounds are known in the state of the art. Thus, for example, WO1993 / 009727A1 describes a device for promoting healing by applying negative pressure to the skin area presenting the wound and around the wound. The apparatus according to WO1993 / 009727A1 comprises a vacuum device for generating a negative pressure, a hermetic wound cover operatively connected to the vacuum device, and a dressing for positioning the wound within the hermetic cover.

[0006] Cupping therapy is a conventional physical therapy in traditional Chinese medicine. According to the theory of traditional Chinese medicine, people are associated with diseases related to meridians. It is said that "the general rule is that there should be no pain, but pain is unacceptable." Cupping therapy is to introduce the negative pressure formed by cupping into the acupuncture points of the treatment area of ​​the human body, and guide it to the meridians to achieve the medical effects of treating injuries and regulating the normal functions of the human body. Cupping has been respected by people since ancient times because of its excellent therapeutic effect. WO2007128163 discloses a cupping therapy device in which a vacuum is created by a vacuum pump.

[0007] In these "negative pressure" treatment devices and methods, when applying negative pressure, when the value reaches a value above or below the value required for optimal treatment, body movements may cause the chamber to compress and / or expand, the chamber volume to fluctuate due to leakage, causing the pressure outside the device to change, and / or electrical / mechanical / software malfunctions may induce the vacuum source to continue to operate outside the predetermined hysteretic control range. This term is defined later in the detailed description of the invention. This is especially true when the device is intended for use over time, under various conditions that may cause changes in the pressure inside the device. Therefore, in order to precisely maintain the therapeutic level of negative pressure, it is necessary to quickly sense any changes in the pressure inside the device so that either an active or passive system can increase or decrease the negative pressure. Furthermore, when sensing and correcting the pressure change, it is beneficial that the necessary adjustments are obtained smoothly so as not to detect the event(s) or confuse the user. This can be achieved by designing one or more components of the pressure regulation system to achieve and maintain the hysteretic control range. Summary of the Invention

[0008] It is an object of the present invention to provide a pressure relief system for assisting in therapeutic control of negative pressure in a therapeutic device. The therapeutic device includes a seal chamber and a seal adapted to form a conforming seal between the device intended to be attached and sealed to the external tissue of a patient, such as the face, neck, wound surrounding area, etc. The therapeutic device is particularly suitable for forming a seal chamber, configured to provide a negative pressure to a target treatment on the external tissue of an individual without exceeding a maximum vacuum value using an active control system, i.e. a pressure sensor and a vacuum control system, and / or a passive type system, i.e. a mechanically actuated pressure relief valve(s). It can also be understood that the device can be used in reverse to prevent excessive positive pressure in devices such as ventilators or resuscitator masks that deliver respiratory gas to the lungs of a patient. The device is exclusively adapted to function passively in low pressure environments (pressures between 9 hPa and 140 hPa) where conventional valve systems tend to be bulky, unreliable, and cost prohibitive.

[0009] The present invention can be used in at least three different negative pressure operating scenarios, as shown in FIG. 1. The first scenario (FIG. 1a) is when the negative vacuum source is a vacuum pump operating at or near the therapeutic negative pressure. In this case, since the vacuum source has a controlled and limited flow rate (and therefore pressure) range, the present invention does not need to utilize a critical orifice to control the gas flow rate (not exceeding the valve's operating capacity), and the pressure relief valve can function primarily as a pop-off valve with hysteretic pressure control in the event that the vacuum pump or other event creates a sufficient negative pressure level to open the valve. In the second scenario (FIG. 1b), the negative vacuum source is a relatively high flow rate vacuum source (such as a hospital vacuum or other external vacuum source) capable of creating a higher than desired vacuum in the vacuum chamber. Such a vacuum source may be unregulated or operably connected to a pressure regulator set to a negative pressure level at, near, or below the targeted therapeutic negative pressure. In this second scenario, the device of the present invention may use a critical orifice in combination with one or more pressure relief valves to maintain a negative pressure level within the device, the critical orifice regulating the flow rate through the device to a maximum level, and the pressure relief valve selected to be within this desired operating flow rate range so that the pressure control system again functions as a reliable over-vacuum pressure relief valve. In a third operating scenario (FIG. 1c), the negative vacuum source operates at a vacuum level above the targeted vacuum level in the vacuum chamber. In this scenario, the pressure control system may utilize a flow control critical orifice to control the flow rate through the system and may utilize one or more pressure relief valves acting as pressure regulators to continuously maintain the operating vacuum near the targeted pressure level. As will be described below, a two valve system, with or without a critical orifice, may be used to provide a controlled "spike" in the vacuum when one of the valves closes. This may be necessary, for example, to reopen a collapsed airway. In a similar manner to these negative pressure scenarios, the pressure control system may be used in positive pressure applications, such as external ventilation scenarios, to prevent lung injury from excessive positive pressure.

[0010] In a related aspect, the invention relates to a method of applying negative pressure therapy to an individual in need thereof, comprising fitting the individual with a treatment device as described herein and applying a therapeutic level of negative pressure within a chamber to increase the patency of the individual's airway. These methods can be for the treatment of sleep apnea, the treatment of snoring, the treatment of complete or partial upper airway collapse, the treatment of complete or partial upper airway obstruction, negative pressure treatment of wounds caused by, for example, trauma or surgery, etc.

[0011] Thus, in a first aspect, the present invention provides a negative pressure therapy device, comprising: This negative pressure therapy device is a chamber element having a housing configured to fit over a portion of the solid to enclose an interior chamber volume over the covered portion of the solid, the housing isolating the interior chamber volume from an ambient gas phase atmosphere exterior to the chamber apparatus; The housing is a vacuum aperture configured to be mated to a vacuum source to evacuate gas from within an interior chamber volume formed upon mating of the chamber element to the solid body; a valve that opens at a first predetermined vacuum level within the interior chamber volume to create an opening through the housing to allow gas to enter the interior chamber volume from the ambient gas phase atmosphere through the opening and that closes at a second predetermined vacuum level within the interior chamber volume, the second predetermined vacuum level being lower than the first predetermined vacuum level; Including, The valve is a semi-elliptical valve head having a peripheral edge, an inner portion facing the interior chamber volume, and an outer portion facing the ambient gas atmosphere; an elastic sleeve on its peripheral edge; and a valve aperture in the valve head that reversibly opens to permit fluid flow therethrough; Including, when the valve is in a closed position, the valve head has a generally convex orientation relative to the housing, and the resilient sleeve is constructed and arranged to fold and extend in a rolling manner to apply a torque to the valve head such that the valve head flips to a generally concave orientation, the concave orientation assisting in opening the valve aperture above a first predetermined vacuum level, and to return it to a generally convex orientation below a second predetermined vacuum level; The chamber apparatus optionally includes a compression element configured and arranged to create a compressed state by applying a compressive force to an outer portion of the valve head when the pressures in the interior chamber volume and the ambient gas phase atmosphere are equal and the valve is closed, the compression force deflecting the outer portion of the valve head inwardly such that the valve aperture is open at the inner portion of the valve head but closes at the outer portion of the valve head in the compressed state.

[0012] In certain embodiments, the device may further include a vacuum source operably coupled to the vacuum aperture and configured to evacuate gas from the internal chamber volume when energized. Such a vacuum source may be a bedside vacuum pump, a vacuum pump provided as an integral component of the housing, a "home" vacuum (e.g., in a facility where vacuum is available as part of the infrastructure of a hospital or other medical facility), or the like. Preferably, the vacuum source provides a gas flow rate at the vacuum source sufficient to generate a vacuum level in the internal chamber volume that is higher than a predetermined first vacuum level when the valve is open. "Vacuum level" refers to a condition lower than the ambient gaseous atmosphere outside the chamber device, and is typically measured in pressure units such as Pascal, mmHg, or mmH2O. An "increase" in vacuum level refers to an increase in the pressure difference between the ambient gaseous atmosphere and the internal chamber volume. Thus, the term "pressure" refers to this pressure difference, and an increase in pressure refers to an increase in this difference.

[0013] In certain embodiments, the device includes a restriction between the internal chamber volume and the vacuum source that creates a critical orifice type gas flow rate. In such devices, the gas flow rate through the vacuum aperture is limited by a critical orifice (creating a choked flow condition) positioned between the internal chamber volume and the vacuum source. Preferably, the dimensions of the critical orifice are selected to provide a vacuum level between a first predetermined vacuum level and a second predetermined vacuum level in the internal chamber volume when the valve is open. As described hereinafter, the choked flow condition prevents the flow rate of the vacuum source from becoming so large as to exceed the valve capacity, preventing an "over-vacuum" condition in the internal chamber volume. That is, if air is removed by the vacuum source at a rate greater than the air that can enter through the valve, the vacuum level may rise to a level that is damaging to the tissue receiving the vacuum. Throttling the gas flow rate in this manner prevents an over-vacuum condition. In various embodiments, the gas flow rate is limited by a "critical orifice" or "choked flow" type gas flow rate to a rate of about 0.2, 0.5, 1, 2, 3, 4, 5, or 10 liters per minute.

[0014] In certain embodiments, the housing further includes a second valve that opens at a third predetermined vacuum level within the internal chamber volume to create a second opening through the housing through which gas can enter the internal chamber volume from the ambient gas phase atmosphere, the third predetermined vacuum level being higher than the first predetermined vacuum level. As described hereinafter, the device can create a temporary vacuum level within the internal chamber volume in preparation for closure of the first valve, the vacuum level being controlled by the second valve. Once unblocked, the second valve closes and the vacuum level is again controlled by the first valve.

[0015] In various embodiments, the first predetermined vacuum level and the second predetermined vacuum level are between about 5 hPa and about 75 hPa, more preferably between about 25 hPa and about 55 hPa, and even more preferably between about 31.3 hPa and about 47.1 hPa. As noted above, the third predetermined vacuum level is higher than the first predetermined vacuum level. In various embodiments, the third predetermined vacuum level is between about 47.1 hPa and 137 hPa.

[0016] As used herein, the term "about" refers to + / - 10% of a given value.

[0017] In certain embodiments, the device is a medical device, and most preferably a negative pressure chamber configured to cover an external portion of the human body. Examples of such medical devices include, but are not limited to, Negative Pressure Wound Closure (NPWT) devices and Continuous Negative Pressure (cNEP) therapy devices for maintaining airway patency by applying a vacuum to the exterior of a human.

[0018] In a related aspect, the invention provides a method of adjusting a vacuum using the devices described herein. In certain embodiments, the method is for NPWT or cNEP. As an example, these methods include: providing a chamber apparatus having a housing enclosing an interior chamber volume containing gas that is evacuated from within the chamber apparatus by application of a vacuum, the housing isolating the interior chamber volume from an ambient gas phase atmosphere exterior to the chamber apparatus, the housing including a valve that opens at a first predetermined vacuum level within the interior chamber volume to create an opening through the housing through which gas from the ambient gas phase atmosphere can enter the interior chamber volume, and the valve that closes at a second predetermined vacuum level within the interior volume, the second predetermined vacuum level being lower than the first predetermined vacuum level; The valve is a semi-elliptical valve head having a peripheral edge, an inner portion facing the interior chamber volume, and an outer portion facing the ambient gas atmosphere; an elastic sleeve on its peripheral edge; and a valve aperture in the valve head that reversibly opens to permit fluid flow therethrough; Including, when the valve is in a closed position, the valve head has a generally convex orientation relative to the housing, and the resilient sleeve is constructed and arranged to fold and extend in a rolling manner to apply a torque to the valve head such that the valve head flips to a generally concave orientation, the concave orientation assisting in opening the valve aperture above a first predetermined vacuum level, and to return it to a generally convex orientation below a second predetermined vacuum level; the chamber apparatus optionally includes a compression element, the compression element configured and arranged to create a compressed state by applying a compressive force to an outer portion of the valve head when the pressures in the interior chamber volume and the ambient gaseous atmosphere are equal and the valve is closed, the compression force being configured and arranged to bias the outer portion inwardly such that the valve aperture is open at the inner portion of the valve head but closes at the outer portion of the valve head in the compressed state; To provide and operably connecting the chamber apparatus to a vacuum source to evacuate gas from the interior volume, where opening and closing of the valve adjusts the vacuum level within the interior volume to a range between a first predetermined vacuum level and a second predetermined vacuum level; Includes. [Brief description of the drawings]

[0019] [Figure 1a] 2 is a schematic diagram of one embodiment of the present invention illustrating an exemplary treatment device 200. An air pump 119 removes air along a path 117 from the portion of the device's vacuum chamber 100 that includes the main chamber 104 and the protected volume 105 separated by a physical structure 107. This air 210 is exhausted through the pump to the outside atmosphere. A pressure relief valve 103 opens at a first predetermined vacuum level within the vacuum chamber 100 to allow air into the vacuum chamber 100 to prevent an overpressure condition from occurring and closes at a second, lower predetermined vacuum level to maintain a desired vacuum level within the vacuum chamber 100 within a desired range. [Figure 1b]1 is a schematic diagram of a second embodiment of the present invention showing an exemplary treatment device 300. An air pump 119 removes air along a path 117 from the portion of the vacuum chamber 100 of the device that includes the main chamber 104 and the protected volume 105 separated by a physical structure 107. This air 210 is exhausted through the pump to the outside atmosphere. A pressure relief valve 103 opens at a first predetermined vacuum level within the vacuum chamber 100 to allow air to enter the vacuum chamber 100 to prevent an overpressure condition from occurring and closes at a second lower predetermined vacuum level to maintain a desired vacuum level within the vacuum chamber 100 within a desired range. A critical orifice 120 is disposed in-line with the air pump 119 to remove the airflow created by the air pump 119 and thereby limit the rate of airflow exiting the vacuum chamber 100 so as not to exceed the inward airflow through the pressure relief valve 103. [Figure 1c] 1 is a schematic diagram of a third embodiment of the present invention showing an exemplary treatment device 400. An air pump 119 removes air along a path 117 from the portion of the vacuum chamber 100 of the device that includes the main chamber 104 and the protected volume 105 separated by a physical structure 107. This air 210 is exhausted through the pump to the outside atmosphere. A pressure relief valve 103 opens at a first predetermined vacuum level within the vacuum chamber 100 to allow air to enter the vacuum chamber 100 to prevent an overpressure condition from occurring and closes at a second lower predetermined vacuum level to maintain a desired vacuum level within the vacuum chamber 100 within a desired range. A critical orifice 120 is disposed in-line with the air pump 119 to remove the airflow created by the air pump 119 and thereby limit the rate of airflow exiting the vacuum chamber 100 so as not to exceed the inward airflow through the pressure relief valve 103. A second pressure relief valve 113 is provided which opens at a predetermined third vacuum level within the vacuum chamber 100 which is different from the first predetermined vacuum level and closes at a lower predetermined fourth vacuum level, providing the ability to temporarily change the vacuum level within the vacuum chamber 100 by selecting which pressure relief valve is allowed to operate. [Diagram 2] 1 is a graphical representation of airflow through critical orifices having different diameters as a function of vacuum source pressure. [Diagram 3] FIG. 1 is an exemplary diagram illustrating an exemplary vacuum control element 101 of the present invention. A physical structure 107, shown as a series of discontinuous air passages, creates a space 105, referred to herein as a "protected volume," that prevents the skin surface or other materials from blocking the underside of the vacuum source connector 110 and the pressure relief valves 103 and 113. In this view, the leaflets of the pressure relief valves 103 and 113 are not shown because they are blocked by the walls of the aperture structure 250 and the compression element 145, respectively. The direction of outward air flow 200 from the vacuum side of the vacuum control element through the vacuum source connector is shown by an arrow, similar to what is the inward direction of air flow from the ambient side of the device 203 to the vacuum side of the device 101 in negative pressure treatment when one or more of the pressure relief valves are open. The dashed line represents the boundary between the ambient side of the device and the vacuum side of the device. Each of the first pressure relief valve element 103 and the second pressure relief valve 113 is slightly compressed by the compression elements 135 and 145, respectively. [Figure 4] An exemplary cross-sectional view of an exemplary vacuum control element 101 of the present invention as shown in Figure 3. Pressure relief valves 103 and 113 each include a dome-shaped semi-elliptical valve element 130 and 140, the domes of which are slightly compressed by compression structures 135 and 145, respectively. [Diagram 5] 1 is an exemplary cross-sectional view of a dome-shaped semi-elliptical valve element 125 corresponding to elements 130 and 140 of FIG. 4. Each is shown in its compressed state, with dashed line 155 indicating the uncompressed state of the valve head. The semi-elliptical valve element 125 includes a resilient sleeve 160 at the peripheral edge 165 of the valve head. Upon compression, the leaflets forming the opening or valve aperture of the valve head 163 remain sealed at the top but open slightly at the bottom. This is also shown in the enlarged view for emphasis. The direction of air flow 210 from the peripheral side of the valve to the negative pressure device chamber when the semi-elliptical pressure relief valve is open is indicated by arrows. [Figure 6]Photograph of the semi-elliptical valve head 125 in a compressed (or "preloaded") state, showing the inner surface of the valve aperture 170, with the valve leaflets partially open toward the inside of the valve head, but remaining closed on the outside of the valve head so that the valve seals against airflow. [Figure 7] An exemplary diagram of an exemplary second vacuum control element 115 of the present invention showing the minimum protected volume 105 protected from obstruction by physical structure 107, the integral vacuum pump 121, the direction of air flow through the vacuum pump housing 200, the direction of air flow 210 through the pressure relief valve 103 and into the negative pressure therapy device chamber, and the compression element 135 of the relief valve 103. [Figure 8] FIG. 8 is an exemplary cross-sectional view of the pressure relief valve device 115 shown in FIG. 7, illustrating the first pressure relief valve element 103, the minimum protected volume 105, the physical structure 107, the integral vacuum pump 121, the direction of air flow 210 exiting the negative pressure therapy device 200, the air flow direction 210 when the pressure relief valve 103 is open, the first semi-elliptical valve head 130, and the first compression element 135. [Figure 9] 1 is a graphical representation of a 20 second pressure relief flow cycle showing the flow rate (in liters / minute) through the pressure relief valve as a function of time (top trace 300) and the corresponding vacuum level (in cmH2O) (bottom trace 320). At 325, the flow rate through the pressure relief valve is near zero as the vacuum begins to build. After reaching a "cracking pressure" 330, the pressure relief valve opens. For a period of time, the flow rate through the pressure relief valve remains nearly constant (315) and the change in the negative pressure level within the device remains nearly flat (325). As the leaflets of the pressure relief valve begin to close, a corresponding decrease in the flow rate through the pressure relief valve begins at 335, and the flow rate decays until the valve closes at 350 (340). [Figure 10]7 is a graphical representation of the vacuum level (in cmH2O) as a function of time for the dome-shaped semi-elliptical valve element lacking compression shown in FIG. 6 during three flow cycles of the same valve element. The lower trace 360 ​​is the first cycle of the valve, showing that as the vacuum level begins to increase at 325, a steady increase in vacuum occurs (320) until a "cracking" pressure 375 (i.e., valve opening) is achieved at approximately 57 cmH2O, and the valve exhibits a somewhat non-linear pressure relief profile until a steady flow of air through the valve is achieved at approximately 7.5 minutes. The second flow cycle then results in pressure traces 365 and 370 as the valve is allowed to return to a fully closed position for a short period of time. These subsequent flow cycles show a lower, repeatable cracking vacuum level 380 and earlier stable air flow, resulting in a steady loss vacuum level 345 until the leaflets of the pressure relief valve element begin to close (350). [Figure 11] 10 is a graph of vacuum level (in cmH2O) as a function of time for a dome-shaped semi-elliptical valve element operated by compression element 135 shown in FIG. 7 during multiple flow cycles of the same valve element. As the vacuum level begins to increase at 325, a steady increase in vacuum occurs (320) until a "cracking" pressure 390 (i.e., valve opening) is achieved at approximately 50 cmH2O, and the valve exhibits a repeatable pressure relief profile over the entire life of use. Valve pre-compression substantially eliminates the variation in initial cracking pressure seen in FIG. [Figure 12] 1 is a graphical representation of air flow through a pressure relief valve apparatus with two pre-compressed dome-shaped semi-elliptical valve elements. The flow cycle graph includes several overlapping traces, with the upper trace 300 showing the flow rate through the pressure relief valve apparatus in liters / minute as a function of time and the lower trace 305 showing the resulting change in vacuum level in cmH2O as a function of time. The first valve cracking pressure 330 occurs at approximately 4 seconds. The first valve element maintains a stable vacuum level 310 at approximately 42 cmH2O, the second valve element maintains a stable vacuum level 385 at approximately 47 cmH2O, and the critical orifice maintains regulated control at approximately 37 cmH2O. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The present invention and its various features and advantageous details will be more fully described with reference to the non-limiting embodiments shown in the accompanying drawings and detailed in the following description. It should be noted that the features shown in the drawings are not necessarily drawn to scale. Descriptions of well-known components and processing techniques are omitted so as not to unnecessarily obscure the invention. The examples used herein are merely intended to facilitate an understanding of how the invention can be implemented and further enable those skilled in the art to implement the invention. Thus, these examples should not be construed as limiting the scope of the invention. Similar reference numerals in the drawings designate corresponding parts in the several views.

[0021] In negative pressure therapy devices and methods, the negative pressure may reach vacuum levels in excess of those required for optimal treatment, or even dangerous to living tissue exposed to such vacuum levels. These undesirable values ​​may be caused by the vacuum source itself being an unregulated high flow source, by electrical / mechanical / software failure of either the external flow regulator or the vacuum source itself resulting in sufficient vacuum flow to create excessive vacuum levels, by bodily movement causing fluctuations in chamber volume due to compression and / or expansion of the chamber and / or movement of tissue entering the chamber during application of negative pressure, leakage in excess of any designed airflow (e.g., for ventilation or cooling) and / or leakage due to momentary seal failure, changes in pressure due to temperature changes, changes in pressure external to the device, etc.

[0022] In a device intended for extended use over many hours while the user is partially sedated, sedated, and / or asleep under a variety of conditions where changes in pressure inside the device may occur, the device itself must be able to respond to such changes in vacuum so as to limit the pressure changes for the safety of the user. Thus, any changes that cause a pressure change inside the device need to be rapidly sensed and responded to by the vacuum source, control system, and / or one or more features of the device so that an increase or decrease in negative pressure can be made to closely maintain a therapeutic level of negative pressure.

[0023] It is an object of the present invention to provide a pressure regulation and / or relief device as a component of a negative pressure device. In various embodiments, the device is configured to establish a desired negative pressure and maintain a desired vacuum level within the vacuum chamber of the device. In other embodiments, the device is configured to release undesired excess vacuum. In particular, a valve is provided that opens when a first negative pressure is reached and reseals when a second (lower) negative pressure is reached, thereby providing for maintaining a desired therapeutic pressure range within the vacuum chamber of the negative pressure device. In various aspects described below, the pressure regulation / relief device can be in the form of one or more pressure relief valve element(s) integrated into the negative pressure therapy device. The valve element(s) are configured to open when the upper limit of the desired vacuum range is reached, thereby allowing outside air to enter the vacuum chamber of the device, thereby preventing the vacuum source from causing an overpressure condition, and to close when the lower limit of the desired vacuum range is reached, thereby preventing an underpressure condition. The valve element(s) thus limit the vacuum level within the vacuum chamber to the desired range.

[0024] As used herein, pressure relief valve element(s) are defined as a component(s) of a vacuum device used to control pressure within the device when it exceeds one or more predetermined negative pressure levels. In certain embodiments, the opening and closing of the pressure relief valve element(s) provides hysteretic control so that the vacuum level is controlled within a range by the flow rate entering the vacuum chamber from the ambient side of the device, most preferably maintaining the vacuum level within a range approximately mid-range of the open and closed values ​​of the pressure relief valve(s).

[0025] In certain embodiments, the device of the present invention can be used with a vacuum source that, if not properly adjusted, may exceed the compensation capacity of the valve element(s). That is, the vacuum source removes air from the vacuum chamber faster than the valve element(s) can admit air. As used herein, an "elevated vacuum source" refers to such a negative pressure source that has an air flow rate greater than the air flow rate that can be accommodated by one or more pressure relief valve elements. To protect against such high vacuum sources, the device of the present invention may optionally include a restriction known as a "critical orifice" in the flow path between the vacuum chamber and the vacuum source. The critical orifice converts the variable flow rate into a downstream controlled flow rate to help achieve the desired negative pressure level in the treatment device, approximately matching the operating range(s) of the one or more pressure relief valve element(s).

[0026] A schematic illustration of an embodiment of the pressure control system(s) can be seen in Figures 1a, 1b, and 1c, which respectively show three possible negative pressure adjustment scenarios. In one embodiment of the invention in the first scenario as shown in Figure 1a, the device 200 comprises a system pump 119, which preferably includes an associated processor, sensors, and pre-programmed parameters. The system pump 119 is operably connected to the vacuum chamber 100 along a flow path 117. The vacuum chamber 100 has a minimum volume 105 and a chamber volume 104. Each of these is operably connected to a first pressure relief valve element 103. The minimum volume 105 is fluidly connected to the chamber volume 104 such that the system pump 119 evacuates air from both volumes under normal operation. A barrier 107 separates the minimum volume 105 from the chamber volume 104 in the sense that it prevents an object (e.g., the skin surface of a patient being treated using negative pressure) from blocking the vacuum pump and the pressure relief valve 103. This provides a separate area where the airflow rate (i.e., vacuum source) and pressure relief valve(s) can create an airflow loop independent of the chamber volume, preventing damage to the skin surface due to excessive pressure conditions. Thus, in this preferred embodiment, continuous application of vacuum is avoided if the minimum volume and pressure relief valve system are inadvertently blocked.

[0027] During normal operation, the pressure relief valve element 103 can function as a "pop-off" type valve that operates in response to any changes in pressure within the chamber element, thus providing a safety element in the unlikely event of the pump being "unbound." During operation of the device, the system pump 119 creates a flow of air through the device, the minimum volume 105 and the chamber volume 100 and out of the device 210 until a desired negative pressure level is achieved within the device. If the negative pressure exceeds the selected pressure relief valve tolerance, the pressure relief valve element 103 opens, allowing airflow from the ambient air outside the pressure relief valve into the minimum volume 105 and the chamber volume 104 until the vacuum pressure drops to a level at which the pressure relief valve element 103 closes.

[0028] In FIG. 1a, the system pump is shown as an element of the device 200. This is for illustrative purposes only. The system pump may be a vacuum source separate from the device itself, such as a bedside or tabletop unit, or a home vacuum in a medical facility, without changing the functionality of the device. The system pump may be an unregulated vacuum source, or may be regulated either within the system pump itself or by providing a vacuum regulator separate from the system pump.

[0029] In a further embodiment of the invention, shown diagrammatically in FIG. 1b, the second scenario involves flow originating from a vacuum source 119 (e.g., a hospital suction vacuum source or vacuum pump) separate from the device 300. In this embodiment, a critical orifice element 120 is used to limit the ability of the vacuum source to exceed the ability of the pressure relief valve 103 to compensate for an overpressure situation. The vacuum flow rate exiting the device 300 is regulated by an aperture in the critical orifice element, which is selected to provide approximately a desired level of airflow from the vacuum source to achieve a controlled level of negative pressure within the device. In a preferred embodiment, this desired level of airflow is approximately at the midpoint of the airflow into the device that the pressure relief valve 103 can provide.

[0030] As an example, the dome-shaped semi-elliptical valve element described herein can open at a first vacuum level but close at a second, lower vacuum level ("hysteresis"). This hysteresis creates a range in airflow through the valve when the valve is open to airflow due to valve leaflet movement ("flutter"). This airflow range can create a vacuum level in the hysteresis range that is managed by the vacuum chamber 100. Using a critical orifice type airflow exiting the vacuum side device to create airflow within this hysteresis range provides an additional level of regulation, thus stabilizing the vacuum level.

[0031] In a further embodiment of the invention, shown diagrammatically in FIG. 1c, a third scenario involves flow occurring from an external high vacuum source 119 operating at a vacuum flow rate above a desired flow rate through a critical orifice 120 operably connected to a minimum volume 105, a chamber volume 104, and one or more pressure relief valves (103, 113). In this scenario, the critical orifice 120 controls the flow rate through the device to create a desired level of negative pressure within the device. In this embodiment, the first pressure relief valve 103 opens at a first vacuum level to allow gas to enter the device so that a first negative pressure level can be maintained, and the second pressure relief valve 113 opens at a different vacuum level to allow gas to enter the device so that a different negative pressure level can be maintained. In various embodiments, the selection between the first and second pressure relief valves can be manually controlled or electronically controlled by a controller within the device 400. In certain embodiments, the pressure relief valve (103 or 113) that opens at the lower vacuum level acts as a default valve, and the negative pressure level provided by that pressure relief valve provides the operating negative pressure level. When the default valve is forced closed, either manually or electronically, a second pressure relief valve that opens at the higher vacuum level becomes functional and is enabled by the negative pressure level provided by the second pressure relief valve. When the forced closure is released and the default valve opens, the operating negative pressure level is resumed.

[0032] The vacuum level adjustment and relief device may further be configured to apply different types of therapeutic target vacuum levels during use due to body movement, device / user position, or onset or relief of upper airway narrowing or obstruction. This approximately constant target negative vacuum level may have a target vacuum level with a predetermined range, upper and lower limits, i.e., a target vacuum level range including a maximum, a minimum and a midpoint value, the maximum and minimum values ​​being within about 5 hPa, and more preferably within about 2 hPa, respectively (+ / - about 5 hPa, and preferably about 2 hPa), and the midpoint value being between about 10 hPa and 60 hPa. It may be appreciated that the range of target vacuum levels accommodates material and manufacturing variations of the vacuum level relief valve, which may range up to less than about 25%, less than about 20%, less than about 10%, and more preferably less than about 5% of the targeted value, or less.

[0033] In one embodiment of the present invention utilizing a high vacuum source and a critical orifice, negative pressure in the chamber element is achieved by using the size of the critical orifice in combination with the flow rate provided by the design pressure range of one or more of the pressure valve element(s). By way of example, the high vacuum source may have an operating flow rate of more than 5 liters per minute, and the critical orifice is selected to regulate the flow rate of air leaving the chamber element to about 2 liters per minute. In one embodiment of the pressure regulation and relief device utilizing a high vacuum source and operably connected to the critical orifice, the critical orifice has a diameter of about 0.6 millimeters and a length of about 1.3 millimeters, thus providing a flow rate of about 2 liters per minute, providing an approximate negative pressure of between about 31 hPa and about 48 hPa in the vacuum chamber when the pressure valve element(s) opens and closes.

[0034] A graphical representation of how the selection of the critical orifice(s) results in limited achievable vacuum levels is shown in FIG. 2. The operating characteristics of the critical orifices can be shown as the flow rate through the critical orifice versus the pressure of the vacuum source. As the vacuum pressure increases, the flow rate through each critical orifice increases until it reaches a maximum flow rate through the critical orifice. This is called a choked flow condition. As shown in FIG. 2, as the vacuum pressure increases from 0 psi to about 7 psi, each critical orifice (0.015 inch, 0.020 inch, and 0.025 inch diameter) reaches a maximum flow rate (approximately 1.0 lpm, 1.5 lpm, and 2.5 lpm, respectively), after which any further increase in vacuum pressure will not increase the flow rate through the critical orifice. The critical orifices may be as simple as holes in a surface, often referred to as an orifice plate, or may take the form of an elongated tube, and in either case may provide a flow path that throttles the flow to a flow rate less than would occur if the flow path were not so throttled. Methods for determining the critical orifice size required to achieve a desired choke flow rate are well known in the art.

[0035] Although described herein with respect to an apparatus configured to provide a negative pressure environment, it should be understood that the present invention may be used in a similar manner with a positive pressure source, such as a ventilator or resuscitator that may operate at a target gas flow rate, e.g., up to 100 liters per minute.

[0036] In one embodiment of the present invention, the regulated vacuum source may be configured as an integral part of the device and configured to provide a substantially constant target negative pressure in the chamber element when the treatment device is fitted to an individual and a therapeutic level of negative pressure is applied in the chamber element. As used herein, "substantially constant" means that the negative pressure is maintained within a predetermined range during normal intended use without perturbations due to short-term transient spikes or losses (increases or decreases) in negative pressure due to movement, swallowing, sneezing, etc. In a preferred embodiment, "substantially constant" is within + / - 25% of the design value during use of the device, more preferably within + / - 20%, even more preferably within + / - 10%, and most preferably within + / - 5%. As described hereinafter, the pressure control system of the regulated vacuum source is also preferably configured to adapt to pressure changes due to unintended leaks into the vacuum chamber by rapidly increasing the pump airflow when pressure loss characteristics indicate a loss of seal integrity, and then return to normal airflow when the operating vacuum level is restored.

[0037] The term "pressure relief component" refers to an element designed to open only when a first (e.g., excessive or undesirable) negative pressure threshold is exceeded and to close when a second (lower or desired) level is achieved again (using a "pop-off valve" type), or a dynamic element designed to open and close to allow a constant flow of air in one direction and to maintain a desired hysteretic control pressure range (using a "regulator" type). "Hysteretic control" refers to a control system whose output reacts less quickly than it would otherwise, taking into account recent system history. For example, a thermostat controlling a heater may switch the heater on when the temperature falls below A, but not turn it off until the temperature exceeds B (e.g., if one wishes to maintain the temperature at 20°C, one may set the thermostat to turn the heater on when the temperature falls below 18°C ​​and to turn it off when the temperature rises above 22°C). In this case, if one wishes to maintain a vacuum level of 25 hPa, the pressure valve may open when the vacuum level reaches 27 hPa, but close when the pressure reaches 23 hPa.

[0038] In certain embodiments, the pressure relief component can be in the form of a separate pressure relief valve element or a pressure relief valve element integrated with the air pump element, the control element, or any aspect of the negative pressure device. In a preferred embodiment, the pressure relief valve element is housed within a protective housing, i.e., a minimum volume to avoid inadvertent blocking. The minimum volume is created by a physical structure isolating a portion of the vacuum side of the device, so that if the physical structure becomes blocked, such as by tissue intrusion, the minimum volume is maintained and directs the flow of vacuum through the pressure relief valve.

[0039] In certain embodiments, the pressure relief component may comprise one or more check valves, diaphragm valves, pinch valves, pop-off valves, solenoid valves, slit valves, or any suitable valve for controlling and regulating pressure within the negative pressure device. The pressure relief valve device is designed to be functionally operable over the entire vacuum range, with preferred vacuum pressures between about 10 hPa and about 140 hPa, whether or not a vacuum above these levels is applied.

[0040] In certain embodiments, as shown in Figures 1c, 3 and 4, the pressure relief component may include multiple pressure relief valves, including, for example, a first pressure relief valve 103 having an initial operating vacuum value, and at least a subsequent second pressure relief valve 113 having the same or higher operating vacuum value as the first pressure relief valve 103, to provide redundancy in case the first pressure relief valve 103 is inadvertently blocked, or to provide different operating vacuum values ​​when the first pressure relief valve 103 is manually blocked. In further embodiments, the first pressure relief valve 103 includes a sealable aperture 250 that can be physically blocked, for example with a finger, to engage the second pressure relief valve 113, allowing the operating pressure value(s) of the second pressure relief valve to achieve a higher vacuum range of the second pressure relief valve 113. Higher levels of negative pressure in the negative pressure device may be used to restore patency of, for example, a collapsed upper airway.

[0041] Although described herein for use in negative pressure applications, in a similar manner, the present invention may also be used in positive pressure applications, such as mechanical ventilation of a patient, to avoid overpressure situations that may damage the patient's airway.

[0042] In certain embodiments, the pressure relief valve element is a one-way valve for relieving excess negative pressure within the negative pressure device and includes an elastomeric slit valve having an inner surface positioned facing the inside of the negative pressure device and an outer surface positioned facing the outside of the device.

[0043] In certain embodiments, the pressure relief valve is a "slit valve" that includes one or more slits that are located on and extend perpendicular to a central axis to create an aperture when the slit valve opens and reseal when the slit valve closes. In certain embodiments, the slit valve is made of a deformable elastomeric material and may be composed of any type of elastomeric material, including, but not limited to, linear low density polyethylene (LLDPE), thermoplastic elastomer (TPE), polyurethane (PUR), and EPDM or rubber (e.g., silicone rubber).

[0044] 5, the pressure relief valve is a dome-shaped semi-elliptical valve element including a semi-elliptical valve head 125 having a peripheral edge 165, an inner portion 163 facing the low pressure side of the vacuum apparatus, an outer portion facing the ambient gaseous atmosphere, a resilient sleeve 160 at the peripheral edge, and a valve aperture 175 that reversibly opens to allow flow therethrough. As used herein, a "semi-elliptical valve head" is defined as a valve in the form of a flexible material in the shape of a planar curve that initially includes a partially compressed convex surface facing the outside of the chamber volume 100 and a concave surface facing the low pressure side of the apparatus, such that when the valve opens, fluid flow 205 proceeds from the ambient pressure side of the apparatus toward the low pressure side. As used herein, the "elastic sleeve" at the peripheral edge of the semi-elliptical valve head is defined as a flexible sidewall portion of the semi-elliptical valve head that is configured and arranged to bend and extend in a rolling manner such that the valve head flips into a generally concave orientation to apply torque to the valve head, which concave orientation assists in opening the valve aperture(s) at the apex of the valve head when the vacuum in the chamber element reaches a first predetermined vacuum level. Examples of suitable valves, processes for manufacturing them, etc. can be found, for example, in U.S. Patent Nos. 1,739,871, 2,147,16, 5,115,950, 5,839,614, 5,927,566, 6,273,305, 6,405,901, and 7,784,652, each of which is incorporated herein by reference in its entirety.

[0045] In a preferred embodiment, the semi-elliptical valve head is made from silicone rubber and the valve aperture includes one or more slits (FIG. 6, 170) at the apexes of the semi-elliptical surface, thereby forming the valve leaflets. When a vacuum is applied and exceeds a predetermined vacuum level within the vacuum chamber, the elastic sleeve moves inward toward the inside of the vacuum chamber and the valve leaflets open, allowing air to pass and relieving the vacuum within the interior of the chamber. The valve head leaflets remain open until a desired range of negative pressure is reached within the chamber, at which point the valve head leaflets relax, the leaflets reseal, and the elastic sleeves of the semi-elliptical valve head return to their original state.

[0046] In preferred embodiments, the valve leaflets have a substantially consistent "cracking" or "opening" level of vacuum pressure throughout all uses. As used herein, "cracking pressure" is defined as the pressure level required to open the valve leaflets to allow air flow. As used herein, substantially consistent cracking pressure is defined as a variation in repeat opening that is preferably less than about 25%, less than about 20%, less than about 15%, less than about 10%, and most preferably less than about 5%, regardless of the time the leaflets are maintained in a closed position.

[0047] A graphical representation of one embodiment of the device operation can be shown in FIG. 9. FIG. 9 shows the operation of the pressure relief valve during an exemplary 20 second flow cycle. It is worth noting that the operation of the valve can and may be performed for shorter or longer periods as needed. The upper trace 300 shows the flow rate in liters / minute as a function of time, and the lower trace 320 shows the corresponding pressure as a function of time after a vacuum perturbation beyond a desired vacuum level. The flow rate 325 gradually increases to the flow rate that the critical orifice assumes to result in a constant flow rate 315. At the same time, a pressure loss can be shown until the cracking pressure 330 of the first pressure relief valve element is reached (FIGS. 3, 4, 7, 8; 103). The pressure relief valve element opens, allowing excess negative pressure to be released until a balance between flow rate and pressure is achieved, as seen in the flow rate trace 315 and the corresponding pressure trace 325. The operation of the pressure relief valve can be dynamic in that it may be fully open or partially open and closed during operation to stabilize the pressure in the device to a predetermined value. In the operation shown in FIG. 9, there is a decay in flow rate 340 and a corresponding increase in pressure 345 is observed until the pressure relief valve closes at 350 .

[0048] Silicone rubber is highly resistant to sterilization methods (e.g., including but not limited to, temperature, chemicals, and radiation) used in the preparation and processing of medical and food processing equipment. However, a known property of silicone rubber is its ability to partially or substantially "self-heal," regaining most or all of its original mechanical properties and shape over time after being distorted. When opposing faces of separated surfaces come into contact with one another, the surfaces that regain contact with one another have demonstrated the ability to re-adhere. The longer the surfaces remain in contact with one another, the greater the adhesion observed. In medical devices, the risk resulting from this repair property is that the increased resistance to the first perturbation or distortion will impede and / or reduce the accuracy of the initial liquid or fluid flow rate or delivery (i.e., cracking pressure in valve-type applications). Stated differently, if the leaflets of a silicone rubber valve are left in contact with one another in the closed position, the initial vacuum pressure required to open the leaflets can be higher compared to the second, third, etc. openings that immediately follow. This presents a challenge to manufacturers, who often must add non-stick surface treatments to facilitate separation of the leaflet surfaces or provide handling and storage instructions specific to opening the valve. These pre-treatments aid but do not completely remove the self-healing properties of the silicone rubber. This not only increases costs for manufacturers, but also increases the risk of product contamination.

[0049] In addition to the pre-adjustment by mechanical design, if the pressure relief valve is made of a material with self-healing adhesive properties such as silicone rubber, the cracking pressure required to open the pressure relief valve can be standardized to avoid inconsistencies in the initial cracking pressure, further eliminating the cracking pressure variation. In one embodiment of the device shown in FIG. 4, the pressure relief valve element(s) (103, 113) comprises a compression element (135, 145) that exerts a compression force on the outside of the valve head in a closed state (i.e., when the pressures of the vacuum side and the ambient gas phase atmosphere are equal). A compression element as used herein is defined as a structural element that exerts a compression force on the convex surface of the semi-elliptical valve head. A compression force is defined as a physical force that exerts pressure on an object to make it more compact. In an embodiment of the present invention, to substantially eliminate the variation in the opening of the leaflets, a compression force is exerted by the compression element (135, 145) on the convex surface of the semi-elliptical valve head (130, 140) to urge the flexible material toward the inside of the vacuum chamber, but can close on the outside of the valve head. The contact surface of the compression element can be flat, raised, or textured as needed to create the desired bias of the valve head.

[0050] In one embodiment of the pressure relief valve, the preloading of the semi-elliptical valve head increases the initial cracking pressure by helping to reduce the combined resealing and adhesion properties of the silicone rubber flap. This preloading is shown in Figures 5 and 6 and ensures that the pressure relief device achieves a reasonably consistent smooth initial opening and fairly consistent subsequent operating cracking pressure regardless of storage time or interval between uses.

[0051] By way of example, FIG. 10 shows a graphical representation of a series of three consecutive flow cycles using a semi-elliptical pressure relief valve that has not been compressed in this manner. For each cycle, as the vacuum begins to increase (325), it increases until it reaches the cracking pressure of the valve. In the trace corresponding to the first cycle of the valve 360, it can be observed that this first cracking pressure 375 is substantially lower than that seen in the second trace 365 and the third trace 370 (corresponding to the second and third flow cycles of the pressure relief valve). Notably, following the first cracking pressure 375 during the first cycle, it is further observed that the pressure relief valve operates in an erratic and unstable manner as a result of the higher pressure required to crack / open the semi-elliptical pressure relief valve. Also notably, the cracking pressures for the second and third cycles are substantially indistinguishable (380) and the trace after the cracking pressure is smooth, indicating a smooth operation of the valve. As the flow terminates, a decay in pressure can be observed (345) until the valve closes (350).

[0052] In a preferred embodiment, the semi-elliptical pressure relief valve is compressed (or "preloaded") (as shown in FIG. 5) to eliminate any fluctuations seen in the cracking pressure (e.g., as shown at 375 in FIG. 10). FIG. 11 shows a graphical representation of a series of consecutive flow cycles using a preloaded semi-elliptical pressure relief valve. With each cycle, as the vacuum level begins to increase (325), the vacuum increases until it reaches the cracking pressure 390 of the pressure relief valve. In the traces corresponding to the first cycle of the valve and subsequent cycles, it can be observed that this cracking pressure 390 is nearly the same throughout.

[0053] In certain embodiments of the invention, the pressure relief device may include more than one pressure relief valve element. When the negative pressure exceeds the tolerances of both the first and second pressure relief valve elements, both valves open continuously, allowing flow 210 to enter the device. Each pressure relief valve element remains open until the pressure returns to a value below the operating pressure of the second pressure relief valve, and subsequently to a value below the operating pressure of the first pressure relief valve. FIG. 12 is a graphical representation showing several flow cycles and corresponding (overlapping) traces of a pressure relief device with two pre-compressed pressure relief valve elements (as seen in FIGS. 3 and 4). Here, when a vacuum is applied through the vacuum aperture 110 and the critical orifice 120, air flows out of the device 200, creating a negative pressure in the internal chamber volume 105 and the chamber volume 100. The lower line 385 shows the opening pressure value of the second pressure relief valve, the middle line 310 shows the opening pressure of the first pressure relief valve, and the upper line 340 shows the pressure provided by the flow from the external regulated source.

[0054] In the graph of Figure 12, the top trace 300 shows the flow rate (in liters / minute as a function of time) through the relief valves, and the bottom trace 305 shows the vacuum level as a function of time. In this example, both the first pressure relief valve element 103 and the second pressure relief valve element 113 open in response to the cracking pressure 330, allowing flow 210 into the device until the pressure within the device increases sufficiently to allow the second pressure relief valve 113 to close. At this point, flow is only through the first pressure relief valve element 103.

[0055] In embodiments of the pressure relief valve with a semi-elliptical valve head made of silicone rubber, the leaflet deflection can be changed, increased or decreased by modifying the physical properties of the valve to maintain the desired operating therapeutic pressure range(s). As used herein, deflection is the degree to which the pressure relief valve is displaced by the load generated by the negative pressure within the device.

[0056] By way of example, a silicone rubber semi-elliptical pressure relief valve may include two mutually perpendicular slits extending radially from the center of a silicone rubber valve dome. In one example device, the semi-elliptical valve head is approximately 28 mm high and approximately 6 mm in diameter, with compression by the compression element of between about 0.25 mm and 0.8 mm to achieve a consistent cracking pressure of approximately 48 hPa, and a natural control range of resealing pressure for the relief valve of approximately 32 hPa.

[0057] Hysteretic control can be particularly useful in providing a range of operating pressures and times to reach those pressures that eliminates abrupt opening and closing (fluttering) of the pressure relief valve caused by open and closed values ​​and times to reach those states that are too short. In embodiments of the invention, the hysteretic control range is between about 5 hPa and about 15 hPa, 5 hPa to 10 hPa or less of the operating pressure of the device. In embodiments of the invention where the pressure relief device comprises more than one pressure relief valve element, the hysteretic control ranges of the pressure relief valve elements can overlap to further enhance, for example, a smooth transition between a first predetermined pressure control value and a second predetermined pressure control value.

[0058] The following examples are included to support preferred embodiments of the invention.

[0059] Embodiment 1. A method for adjusting a vacuum level, comprising: providing a chamber apparatus having a housing enclosing an interior chamber volume containing gas that is evacuated from within the chamber apparatus by application of a vacuum, the housing isolating the interior chamber volume from an ambient gas phase atmosphere external to the chamber apparatus, the housing including a valve that opens at a first predetermined vacuum level within the interior chamber volume to create an opening through the housing through which gas from the ambient gas phase atmosphere can enter the interior chamber volume, the valve closing at a second predetermined vacuum level within the interior volume, the second predetermined vacuum level being lower than the first predetermined vacuum level; The valve is a semi-elliptical valve head having a peripheral edge, an inner side facing said interior chamber volume, and an outer side facing said ambient gas atmosphere; an elastic sleeve on said peripheral edge thereof; and a valve aperture in the valve head that reversibly opens to permit fluid flow therethrough; Including, when the valve is in a closed position, the valve head has a generally convex orientation relative to the housing, and the resilient sleeve is constructed and arranged to fold and extend in a rolling manner to apply a torque to the valve head such that the valve head flips to a generally concave orientation, the concave orientation assisting in opening the valve aperture above the first predetermined vacuum level, and to return it to a generally convex orientation below the second predetermined vacuum level. The providing; operatively connecting the chamber apparatus to a vacuum source to evacuate the gas from the interior volume, wherein opening and closing of the valve adjusts the vacuum level within the interior volume to a range between the first predetermined vacuum level and the second predetermined vacuum level; The method comprising:

[0060] Embodiment 2. The method of embodiment 1, wherein the chamber apparatus includes a compression element configured and arranged to create a compressed state by applying a compressive force to the outer portion of the valve head when the pressure in the internal chamber volume and the ambient gas phase atmosphere are equal and the valve is closed, the compression force deflecting the outer portion of the valve head inwardly such that the valve aperture is open at the inner portion of the valve head but closes at the outer portion of the valve head in the compressed state.

[0061] Embodiment 3. A negative pressure therapy device comprising a chamber element having a housing, the housing is configured to fit over a portion of an individual to enclose an interior chamber volume over the covered portion of the individual, the housing isolating the interior chamber volume from an ambient gas phase atmosphere external to the chamber apparatus; The housing includes: a vacuum aperture configured to be mated to a vacuum source to evacuate gas from within the interior chamber volume formed upon mating of the chamber element to the solid body; a valve that opens at a first predetermined vacuum level within the internal chamber volume to create an opening through the housing such that gas can enter the internal chamber volume from the ambient gas phase atmosphere through the opening and that closes at a second predetermined vacuum level within the internal chamber volume, the second predetermined vacuum level being lower than the first predetermined vacuum level; Including, The valve is a semi-elliptical valve head having a peripheral edge, an inner side facing said interior chamber volume, and an outer side facing said ambient gas atmosphere; an elastic sleeve on said peripheral edge thereof; and a valve aperture in the valve head that reversibly opens to permit fluid flow therethrough; Including, when the valve is in a closed position, the valve head has a generally convex orientation relative to the housing, and the resilient sleeve is constructed and arranged to fold and extend in a rolling manner to apply a torque to the valve head such that the valve head flips to a generally concave orientation, the concave orientation assisting in opening the valve aperture above the first predetermined vacuum level, and to return it to a generally convex orientation below the second predetermined vacuum level. The negative pressure therapy device.

[0062] Embodiment 4. A negative pressure therapy device as described in embodiment 3, wherein the chamber device includes a compression element configured and arranged to create a compressed state by applying a compressive force to the outer portion of the valve head when the pressure in the internal chamber volume and the ambient gas phase atmosphere are equal and the valve is closed, the compression force deflecting the outer portion of the valve head inwardly such that the valve aperture opens at the inner portion of the valve head but closes at the outer portion of the valve head in the compressed state.

[0063] Embodiment 5. A negative pressure treatment device as described in embodiment 3 or 4, further comprising a vacuum source operably connected to the vacuum aperture and configured to evacuate the gas from the internal chamber volume when energized.

[0064] Embodiment 6. A negative pressure treatment device as described in embodiment 5, wherein the vacuum source supplies a gas flow rate sufficient to generate a vacuum level within the internal chamber volume higher than the predetermined first vacuum level when the valve is open.

[0065] Embodiment 7. A negative pressure therapy device as described in embodiment 6, wherein the gas flow rate through the vacuum aperture is restricted by a cross-sectional area of ​​a flow path positioned between the internal chamber volume and the vacuum source, the flow path providing a critical orifice type gas flow rate, and the gas flow rate is restricted by the critical orifice type gas flow rate to a flow rate that maintains a vacuum level in the internal chamber volume that is between the first predetermined vacuum level and the second predetermined vacuum level when the valve is open.

[0066] Embodiment 8. A negative pressure therapy device as described in any one of embodiments 3 to 7, wherein the housing further includes a second valve that opens at a predetermined third vacuum level within the internal chamber volume to create a second opening through the housing, and gas can enter the internal chamber volume from the ambient gas phase atmosphere through the opening, and the predetermined third vacuum level is higher than the predetermined first vacuum level.

[0067] Embodiment 9. The method of embodiment 1 or 2, wherein the vacuum source supplies a gas flow rate to the vacuum source sufficient to generate a vacuum level in the interior chamber volume that is higher than the first predetermined vacuum level when the valve is open.

[0068] Embodiment 10. The method of embodiment 9, wherein the vacuum source is coupled to a vacuum aperture in the housing, and the gas flow rate through the vacuum aperture is restricted by a cross-sectional area of ​​a flow passage positioned between the internal chamber volume and the vacuum source, the flow passage providing a critical orifice type gas flow rate, and the gas flow rate is restricted by the critical orifice type gas flow rate to a flow rate that maintains a vacuum level in the internal chamber volume that is between the first predetermined vacuum level and the second predetermined vacuum level when the valve is open.

[0069] Embodiment 11. The method of any one of embodiments 1, 2, 9 or 10, wherein the housing further includes a second valve that opens at a predetermined third vacuum level within the internal chamber volume to create a second opening through the housing, and gas can enter the internal chamber volume from the ambient gas phase atmosphere through the opening, the third predetermined vacuum level being higher than the first predetermined vacuum level.

[0070] Embodiment 12. The method of embodiment 11, wherein the valve is configured to selectively and reversibly block from allowing fluid flow therethrough such that blocking of the valve causes the second valve to open until the vacuum level within the interior chamber volume reaches the predetermined third vacuum level and the blocking is reversed.

[0071] Embodiment 13. A negative pressure therapy device as described in embodiment 7, wherein the gas flow rate is limited to a flow rate of approximately 2 liters per minute by the critical orifice type gas flow rate.

[0072] Embodiment 14. A negative pressure treatment device described in any one of embodiments 3 to 8 or 13, wherein the first predetermined vacuum level and the second predetermined vacuum level are between about 31.3 hPa and about 47.1 hPa.

[0073] Embodiment 15. A negative pressure therapy device as described in embodiment 8, wherein the third predetermined vacuum level is between approximately 47.1 hPa and 137 hPa.

[0074] Embodiment 16. A negative pressure therapy device described in any one of embodiments 3-8 or 13-15, wherein the device is a medical device.

[0075] Embodiment 17. A negative pressure treatment device described in any one of embodiments 3 to 8 or 13 to 16, wherein the medical device is a negative pressure chamber configured to cover the outside of the human body.

[0076] Embodiment 18. A negative pressure therapy device as described in embodiment 17, wherein the negative pressure chamber is a negative pressure wound closure (NPWT) device.

[0077] Embodiment 19. A negative pressure therapy device as described in embodiment 17, wherein the negative pressure chamber is a continuous external negative pressure (cNEP) therapy device adapted to maintain airway patency by applying a vacuum external to a human.

[0078] Embodiment 20. The method of embodiment 10, wherein the gas flow rate is limited by the critical orifice type gas flow rate to a flow rate of about 2 liters per minute.

[0079] Embodiment 21. The method of any one of embodiments 8, 1, 2, 9-12, or 20, wherein the first predetermined vacuum level and the second predetermined vacuum level are between about 31.3 hPa and about 47.1 hPa.

[0080] Embodiment 22. The method of embodiment 11, wherein the third predetermined vacuum level is between about 47.1 hPa and 137 hPa.

[0081] Embodiment 23. The method of any one of embodiments 1, 2, 9-12, or 20-22, wherein the device is a medical device.

[0082] Embodiment 24. The method of embodiment 23, wherein the medical device is a negative pressure chamber configured to cover the exterior of the human body.

[0083] Embodiment 25. The method of embodiment 24, wherein the negative pressure chamber is a NPWT device.

[0084] Embodiment 26. The method of embodiment 24, wherein the negative pressure chamber is a cNEP treatment device adapted to maintain airway patency by applying a vacuum external to a human.

[0085] Those skilled in the art will appreciate that the conception underlying the present disclosure may be readily utilized as a basis for the design of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.

[0086] The structural embodiments of the device may vary based on the size of the device, and the description provided herein is a guide to the functional aspects and implementations.

[0087] It will be readily appreciated by one skilled in the art that the present invention is well adapted to carry out the objects and obtain the ends and advantages mentioned, as well as those inherent therein. The present examples described herein are illustrative and are not intended to limit the scope of the invention.

[0088] It will be apparent to those skilled in the art that various modifications and variations can be made in the invention disclosed herein without departing from the spirit or scope of the invention.

[0089] All publications and patent applications mentioned in this specification are indicative of the level of those skilled in the art to which this invention pertains. All publications and patent applications are herein incorporated by reference to the same extent as if each individual publication was specifically and individually indicated to be incorporated by reference.

[0090] The present invention illustratively described herein can be suitably practiced without any element(s) or limitation(s) not specifically disclosed herein. Thus, for example, in each example herein, any of the terms "comprising," "consisting essentially of," and "consisting of" can be replaced with either of the other two terms. Furthermore, the terms and expressions employed herein have been used as terms of description and not of limitation, and the use of such terms and expressions is not intended to exclude any equivalents of the features shown and described or portions thereof, but rather, it is recognized that various modifications are possible within the scope of the technology of the claims. Thus, although the present invention has been specifically disclosed by preferred embodiments and optional features, it will be understood that modifications and variations of the concepts disclosed herein can be utilized by those skilled in the art, and that such modifications and variations are within the scope of the present invention, as defined by the appended claims.

[0091] Other embodiments are within the scope of the following claims.

Claims

1. 1. A method for adjusting a vacuum level, comprising the steps of: providing a chamber apparatus having a housing enclosing an interior chamber volume containing gas that is evacuated from within the chamber apparatus by application of a vacuum, the housing isolating the interior chamber volume from an ambient gas phase atmosphere external to the chamber apparatus, the housing including a valve that opens at a first predetermined vacuum level within the interior chamber volume to create an opening through the housing through which gas from the ambient gas phase atmosphere can enter the interior chamber volume, the valve closing at a second predetermined vacuum level within the interior volume, the second predetermined vacuum level being lower than the first predetermined vacuum level; The valve is a semi-elliptical valve head having a peripheral edge, an inner side facing said interior chamber volume, and an outer side facing said ambient gas atmosphere; an elastic sleeve on said peripheral edge; a valve aperture in said valve head that reversibly opens to permit fluid flow therethrough; Including, when the valve is in a closed position, the valve head has a generally convex orientation relative to the housing, and the resilient sleeve is constructed and arranged to fold and extend in a rolling manner to apply a torque to the valve head such that the valve head flips to a generally concave orientation, the concave orientation assisting in opening the valve aperture above the first predetermined vacuum level, and to return it to a generally convex orientation below the second predetermined vacuum level; operably connecting the chamber apparatus to a vacuum source to evacuate the gas from the interior volume, wherein opening and closing the valve adjusts a vacuum level within the interior volume to a range between the first predetermined vacuum level and the second predetermined vacuum level; A method comprising:

2. 2. The method of claim 1, wherein the chamber apparatus includes a compression element configured and arranged to create a compressed state by applying a compressive force to an exterior portion of the valve head when pressures in the interior chamber volume and the ambient gas phase atmosphere are equal and the valve is closed, the compression force biasing the exterior portion of the valve head inwardly such that the valve aperture is open at the interior portion of the valve head but closes at the exterior portion of the valve head in the compressed state.

3. A negative pressure therapy device, a chamber element having a housing configured to fit over a portion of a solid body, thereby enclosing an interior chamber volume over the covered portion of the solid body, the housing isolating the interior chamber volume from an ambient gaseous atmosphere external to the chamber apparatus; A negative pressure therapy device comprising: The housing includes: a vacuum aperture configured to be mated to a vacuum source to evacuate gas from within an interior chamber volume formed upon mating of the chamber element to the solid body; a valve that opens at a first predetermined vacuum level within the interior chamber volume to create an opening through the housing such that gas can enter the interior chamber volume from the ambient gas phase atmosphere through the opening and that closes at a second predetermined vacuum level within the interior chamber volume, the second predetermined vacuum level being lower than the first predetermined vacuum level; Including, The valve is a semi-elliptical valve head having a peripheral edge, an inner side facing said interior chamber volume, and an outer side facing said ambient gas atmosphere; an elastic sleeve on said peripheral edge; a valve aperture in said valve head that reversibly opens to permit fluid flow therethrough; Including, 1. A negative pressure therapy device configured and arranged such that when the valve is in a closed position, the valve head has a generally convex orientation relative to the housing, and the elastic sleeve is folded and extended in a rolling manner to apply a torque to the valve head such that the valve head flips to a generally concave orientation, the concave orientation assisting in opening the valve aperture above the first predetermined vacuum level and returning it to the generally convex orientation below the second predetermined vacuum level.

4. 4. The negative pressure therapy device of claim 3, wherein the chamber apparatus includes a compression element configured and arranged to create a compressed state by applying a compressive force to an outer portion of the valve head when pressures in the internal chamber volume and the ambient gas phase atmosphere are equal and the valve is closed, the compression force biasing the outer portion of the valve head inward such that the valve aperture opens at the inner portion of the valve head but closes at the outer portion of the valve head in the compressed state.

5. 5. The negative pressure therapy device of claim 3 or 4, further comprising a vacuum source operably coupled to the vacuum aperture and configured to evacuate the gas from the internal chamber volume when energized, optionally the vacuum source providing a gas flow rate to the vacuum source sufficient to generate a vacuum level in the internal chamber volume higher than the first predetermined vacuum level when the valve is open, optionally the gas flow rate through the vacuum aperture is restricted by a cross-sectional area of ​​a flow path positioned between the internal chamber volume and the vacuum source, the flow path providing a critical orifice type gas flow rate, the gas flow rate being limited by the critical orifice type gas flow rate to a flow rate that maintains a vacuum level in the internal chamber volume that is between the first predetermined vacuum level and the second predetermined vacuum level when the valve is open, optionally the gas flow rate being limited by the critical orifice type gas flow rate to a flow rate of about 2 liters per minute.

6. The negative pressure therapy device of any one of claims 3 to 5, wherein the housing further comprises a second valve that opens at a predetermined third vacuum level within the internal chamber volume to create a second opening through the housing, wherein gas can enter the internal chamber volume from the ambient gas phase atmosphere through the opening, the predetermined third vacuum level being higher than the predetermined first vacuum level, and optionally the predetermined first vacuum level and the predetermined second vacuum level being between about 31.3 hPa and about 47.1 hPa.

7. 3. The method of claim 1 or 2, wherein the vacuum source supplies a gas flow rate sufficient to generate a vacuum level in the internal chamber volume that is higher than the first predetermined vacuum level when the valve is open, and optionally the vacuum source is coupled to a vacuum aperture in the housing, the gas flow rate through the vacuum aperture being restricted by a cross-sectional area of ​​a flow passage positioned between the internal chamber volume and the vacuum source, the flow passage providing a critical orifice type gas flow rate, the gas flow rate being restricted by the critical orifice type gas flow rate to a flow rate that maintains a vacuum level in the internal chamber volume that is between the first predetermined vacuum level and the second predetermined vacuum level when the valve is open, and optionally the gas flow rate being restricted by the critical orifice type gas flow rate to a flow rate of about 2 liters per minute.

8. 8. The method of claim 1, wherein the housing further comprises a second valve that opens at a predetermined third vacuum level within the internal chamber volume to create a second opening through the housing, wherein gas can enter the internal chamber volume through the opening from the ambient gas phase atmosphere, the predetermined third vacuum level being higher than the predetermined first vacuum level, and the valve is configured to selectively and reversibly block from permitting flow therethrough such that blocking of the valve causes the second valve to open until the vacuum level within the internal chamber volume reaches the predetermined third vacuum level and the blocking is reversed.

9. The negative pressure therapy device of any one of claims 3 to 6, wherein the first predetermined vacuum level and the second predetermined vacuum level are between about 31.3 hPa and about 47.1 hPa.

10. The negative pressure therapy device of any one of claims 3 to 6 and 9, wherein the device is a medical device.

11. A negative pressure therapy device according to any one of claims 3 to 6 and 9 to 10, wherein the medical device is a negative pressure chamber configured to cover the exterior of a human body, and optionally the negative pressure chamber is a negative pressure wound closure (NPWT) device or the negative pressure chamber is a continuous external negative pressure (cNEP) therapy device adapted to maintain airway patency by applying a vacuum to the exterior of a human body.

12. 9. The method of claim 1, 2, 7, or 8, wherein the first predetermined vacuum level and the second predetermined vacuum level are between about 31.3 hPa and about 47.1 hPa.

13. The method of claim 8, wherein the third predetermined vacuum level is between about 47.1 hPa and 137 hPa.

14. The method of any one of claims 1, 2, 7-8, and 12-13, wherein the device is a medical device.

15. 15. The method of claim 14, wherein the medical device is a negative pressure chamber configured to cover the exterior of a human body, and optionally the negative pressure chamber is a NPWT device or the negative pressure chamber is a cNEP therapy device adapted to maintain airway patency by applying a vacuum to the exterior of a human.

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