Biodegradable valves for endoscopes

Abstract

This invention relates to apparatus, systems, and methods for a valve assembly (140) for a medical device (100). The valve (300) has a cap (302), a rod (308) movable within a valve body (330), and a spring member (306) between the cap and the valve body to move the valve within the valve body. The valve rod (308) and / or the spring member (306) are made of a biodegradable material, which may be a metal. The biodegradable material has a higher degradation rate than conventional metal valve components to reduce the environmental impact of valve disposal.

Description

Cross-references to related applications

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 581,041, filed September 7, 2023, the disclosure of which is incorporated herein by reference. Technical Field

[0002] This disclosure relates generally to valve assemblies and methods, and particularly to valve assemblies and methods for use with endoscopes. Background Technology

[0003] A wide variety of in-body medical devices and systems have been developed for medical applications, such as endoscopic surgery. Some of these devices and systems include guidewires, catheters, catheter systems, endoscopic instruments, etc. These devices and systems are manufactured using any of a variety of different methods and can be used according to any of these methods. Each of these medical devices, systems, and methods is known to have certain advantages and disadvantages.

[0004] Some medical devices include “single-use” components that are intended to be discarded after a short window of time, such as a single day or a single surgery. These single-use components significantly increase the environmental costs associated with surgery because they are typically classified as biological waste. When components are made of steel or another flexible material, the time and / or energy required to decompose them can be significant. There is a need for medical device components that are easier to decompose in order to reduce the overall environmental burden associated with their disposal. Summary of the Invention

[0005] This disclosure provides designs, materials, manufacturing methods, and alternative uses for medical devices and systems. In a first embodiment, a valve assembly for a medical device may include a valve body, a valve cover located above the valve body, a spring member positioned between the valve cover and the valve body, and a valve stem connected to the valve cover; the valve body has an air inlet passage, an air outlet passage, a water inlet passage, and a water outlet passage; the spring member applies an upward force against the valve cover when the valve cover is pushed downward relative to the valve body; the valve stem is configured to translate between an upper position and a lower position within the valve body, the valve stem including sidewalls and a central lumen extending from an air inlet in the valve stem sidewall to an air hole in the valve cover, and the valve stem is integrally made of a biodegradable metal.

[0006] As an alternative to or addition to any of the above examples, the degradable metal may include Mg. The degradable metal may be pure Mg or a Mg alloy having a higher degradation rate than pure Mg.

[0007] As an alternative to or addition to any of the above examples, the biodegradable metal may include Zn. The biodegradable metal is pure Zn or a Zn alloy having a higher degradation rate than pure Zn.

[0008] As an alternative to or addition to any of the above examples, the biodegradable metal may include Fe. The biodegradable metal may be an Fe alloy having a higher degradation rate than pure Fe.

[0009] As an alternative to or addition to any of the above examples, the spring component may be made entirely of biodegradable metal.

[0010] In another example, a valve assembly for a medical device may include a valve body, a valve cover located on the valve body, a spring member, and a valve stem connected to the valve cover; the valve body has an air inlet passage, an air outlet passage, a water inlet passage, and a water outlet passage; the spring member is integrally made of a biodegradable material and is positioned between the valve cover and the valve body such that when the valve cover is pushed downward relative to the valve body, the spring member applies an upward force against the valve cover; the valve stem is configured to translate within the valve body between an upper position and a lower position, and the valve stem includes sidewalls and a central lumen extending from an air inlet in the valve stem sidewall to an air hole in the valve cover.

[0011] As an alternative to or addition to any of the above examples, the spring member may be a spring bar.

[0012] As an alternative to or addition to any of the above examples, the spring component may be a wave washer assembly.

[0013] As an alternative to or addition to any of the above examples, the spring component may be a disc washer assembly.

[0014] As an alternative to or addition to any of the above examples, biodegradable materials may include at least one of Mg, Zn, and Fe.

[0015] As an alternative or addition to any of the above examples, the biodegradable material may be pure Mg, a Mg alloy having a higher degradation rate than pure Mg, pure Zn, a Zn alloy having a higher degradation rate than pure Zn, or an Fe alloy having a higher degradation rate than pure Fe.

[0016] As an alternative to or addition to any of the above examples, the valve stem may be made entirely of biodegradable metal.

[0017] These and other features and advantages of this disclosure will become apparent from the following detailed description, and the scope of the claimed invention is set forth in the appended claims. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various embodiments and, together with the description, serve to explain the principles of this disclosure.

[0019] Figure 1 A schematic diagram of the components of an exemplary endoscope is shown;

[0020] Figure 2 A schematic diagram of the components of an exemplary endoscope system is shown;

[0021] Figure 3 A perspective view of an exemplary supply valve is shown;

[0022] Figure 3A A schematic cross-sectional view of an exemplary supply valve is shown, in which the valve is in a first configuration;

[0023] Figure 3B A schematic cross-sectional view of an exemplary supply valve is shown, in which the valve is in a second configuration;

[0024] Figure 3C A schematic cross-sectional view of an exemplary supply valve is shown, in which the valve is in a third configuration;

[0025] Figure 3D A schematic cross-sectional view of the upper portion of an exemplary supply valve and the spring member is shown;

[0026] Figure 4A A perspective view of an exemplary spring component is shown;

[0027] Figure 4B It shows having Figure 4A A schematic cross-sectional view of the upper part of an illustrative supply valve for a spring component;

[0028] Figure 5A A perspective view of an exemplary spring component is shown;

[0029] Figure 5B It shows having Figure 5A A schematic cross-sectional view of the upper part of an illustrative supply valve for a spring component;

[0030] Figure 6A A perspective view of an exemplary spring component is shown;

[0031] Figure 6B It shows having Figure 6A A schematic cross-sectional view of the upper part of the spring component of the supply valve.

[0032] Although this disclosure can be modified in various ways and alternatives, its details have been shown by way of example in the drawings and will be described in detail. However, it should be understood that it is not intended to limit the invention to the specific embodiments described. Rather, it is intended to cover all modifications, equivalents, and alternatives that fall within the spirit and scope of this disclosure. Detailed Implementation

[0033] This disclosure is now described with reference to an exemplary medical system that can be used in endoscopic medical procedures. However, it should be noted that the reference to this particular procedure is for convenience only and is not intended to limit the scope of this disclosure. Those skilled in the art will recognize that the basic ideas of the disclosed apparatus and related methods of use can be applied to any suitable procedure, medical or otherwise. This disclosure may be understood with reference to the following description and accompanying drawings, wherein similar elements are designated by the same reference numerals.

[0034] All numerical values ​​herein are assumed to be modified by the term “about”, whether explicitly indicated or not. In the context of numerical values, the term “about” generally refers to a range of numbers that a person skilled in the art would consider equivalent to the stated value (e.g., having the same function or result). In many cases, the term “about” may include numbers rounded to the nearest significant figure. Other uses of the term “about” (e.g., in contexts other than numerical values) are assumed to have their common and conventional definitions, as understood and consistent with the context of the specification, unless otherwise specified.

[0035] Numerical ranges expressed by endpoints include all numbers within that range, including the endpoints (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5). Although some suitable dimensions, ranges, and / or values ​​relating to various components, features, and / or specifications are disclosed, those skilled in the art will understand, inspired by this invention, that desired dimensions, ranges, and / or values ​​may deviate from those explicitly disclosed.

[0036] As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly indicates otherwise. As used in this specification and the appended claims, the term “or” is generally used in its meaning to include “and / or” unless the context clearly indicates otherwise. It should be noted that, for ease of understanding, certain features of this disclosure may be described in the singular form, even if such features may be plural or repeated within one or more disclosed embodiments. Each of these features may include and / or be covered by the singular disclosure, unless expressly stated to the contrary. For purposes of simplicity and clarity, not all elements of this disclosure are necessarily shown in every figure or discussed in detail below. However, it will be understood that the following discussion can be applied equivalently to any and / or all of more than one component, unless expressly stated to the contrary. Furthermore, for clarity, not all instances of some elements or features are shown in every figure.

[0037] It should be noted that references to "one embodiment," "some embodiments," "other embodiments," etc., in the specification indicate that the described embodiments may include specific features, structures, or characteristics, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Additionally, when a specific feature, structure, or characteristic is described in conjunction with one embodiment, those skilled in the art will understand that the specific feature, structure, or characteristic is implemented in conjunction with other embodiments, whether explicitly described or not, unless clearly stated to the contrary. That is, the various individual elements described below, even if not explicitly shown in a specific combination, are contemplated as combinable or arrangeable to form other additional embodiments or to supplement and / or enrich the described embodiments, as will be understood by those skilled in the art.

[0038] For clarity, certain identifying numerical names (e.g., first, second, third, fourth, etc.) may be used throughout the specification and / or claims to name various described and / or claimed features and / or to distinguish them. It should be understood that the numerical names are not intended to be restrictive and are merely illustrative. In some embodiments, for brevity and clarity, changes and deviations may be made to the previously used numerical names. That is, a feature identified as a “first” element may subsequently be referred to as a “second” element, a “third” element, etc., or may be omitted entirely, and / or different features may be referred to as a “first” element. In each case, the meaning and / or designation will be apparent to those skilled in the art.

[0039] The detailed description is intended to be illustrative and does not limit the scope of this disclosure. Those skilled in the art will recognize that the various elements described can be arranged in various combinations and configurations without departing from the scope of this disclosure. The detailed description illustrates exemplary embodiments of this disclosure.

[0040] refer to Figure 1 An exemplary endoscope 100 is shown; and Figure 2 An exemplary endoscope system 200 is shown. Endoscope 100 may include an elongated tube or shaft 100a configured for insertion into a subject (e.g., a patient).

[0041] The light source 205 of the endoscope system 200 can supply illumination light to the distal portion 100b of the endoscope 100. The distal portion 100b of the endoscope 100 can house an imager (e.g., a CCD or CMOS imager) (not shown). The light source 205 (e.g., a lamp) can be located in a video processing unit 210, which processes signals input from the imager and outputs the processed video signal to a video monitor (not shown) for observation. By housing a pressure pump 215 (such as an air supply pump) in the video processing unit 210, the unit 210 can also serve as a component of an air / water supply circuit.

[0042] The endoscope axis 100a may include a distal end 100c (e.g., a distal end unit) disposed at a distal portion 100b of the axis 100a, and a flexible bend 105 proximal to the distal end 100c. The flexible bend 105 may include a hinge joint (not shown) to assist in the swivel of the distal end 100c. A gas / lens cleaning nozzle 220 is located on the end face 100d of the distal end 100c of the endoscope 100 for supplying gas to blow into the patient at the treatment area and for supplying water to clean the lens covering the imager. An irrigation opening 225 in the end face 100d supplies irrigation fluid to the patient's treatment area. An illumination window (not shown) and an opening 230 leading to a working channel 235 may also be included on the end face 100d of the distal end 100c, the illumination window delivering illumination light to the treatment area, and the working channel 235 extending along the axis 100a to deliver tools to the treatment area. The working channel 235 may extend along axis 100a to a channel opening 110 located distal to the operating handle 115 (e.g., proximal handle) of endoscope 100. Biopsy valve 120 may be used to seal the channel opening 110 to prevent unwanted fluid leakage.

[0043] The operating handle 115 may be provided with a knob 125 to provide remote four-way steering at the distal end via a cable (e.g., one knob controls up-and-down steering, and another knob controls left-and-right steering), the cable being connected to a hinge joint in the flexible portion 105. A plurality of video switches 130 for remotely operating the video processing unit 210 may be arranged on the proximal side of the handle 115.

[0044] The handle 115 may be provided with a dual-valve position 135. One of the valve positions 135 may receive a gas / water valve 140 for operating the blow-in gas and lens water supply operations. The gas supply line 240a and the lens cleaning supply line 245a travel distally from the gas / water valve 140 along the axis 100a and converge at the distal end 100c near the gas / cleaning nozzle 220. Figure 2 ).

[0045] Another valve position 135 can receive a suction valve 145 for operating a suction operation. A suction supply line 250a can travel distally from the suction valve 145 along axis 100a to a junction that is in fluid communication with the working passage 235 of the endoscope 100.

[0046] The operating handle 115 is electrically and fluidly connected to the video processing unit 210 via a flexible umbilicus 260 extending therebetween and a connector portion 265. The flexible umbilicus 260 has a gas (e.g., air or CO2) supply line 240b, a lens cleaning supply line 245b, a suction supply line 250b, an infusion supply line 255b, a light guide (not shown), and an electrical signal cable (not shown). When inserted into the video processing unit 210, the connector portion 265 connects the light source 205 in the video processing unit to the light guide. The light guide travels along the length of the endoscope axis 100a and the umbilicus 260 to transmit light to the distal end 100c of the endoscope 100. When inserted into the video processing unit 210, the connector portion 265 also connects an air pump 215 to the gas supply line 240b in the umbilicus 260.

[0047] A water reservoir or container 270 (e.g., a water bottle) is fluidly connected to the endoscope 100 via a connector portion 265 and an umbilicus 260. A gas supply line 240c extends from one end located in an air gap 275 to a detachable gas / lens cleaning connection 290 on the outside of the connector portion 265, the air gap 275 being located between the top 280 (e.g., a bottle cap) of the reservoir 270 and the remaining water 285 in the reservoir. A gas supply line 240b of the umbilicus 260 branches in the connector portion 265 to fluidly communicate with the gas supply line 240c and an air pump 215 at the detachable gas / lens cleaning connection 290. A lens cleaning line 245c (with one end located at the bottom of the reservoir 270) extends through the top 280 of the reservoir 270 to the same detachable connection 290 on the connector portion 265 as the gas supply line 240c. In other embodiments, the connections may be separate and / or separable from each other. Connector portion 265 may also have a detachable infusion connection 293 for an infusion supply line (not shown) that runs from an infusion water source (not shown) to an infusion supply line 255b in the umbilicus 260. In some embodiments, infusion water is supplied via a pump (e.g., a peristaltic pump) from a water source (not shown) independent of the water reservoir 270. In other embodiments, the infusion supply line and the lens cleaning line 245c may draw water from the same reservoir. Connector portion 265 may also include a detachable suction connection 295 for suction supply lines 250b and 250a, which fluidly connects a vacuum source (e.g., a hospital suction device) (not shown) to the umbilicus 260 and the endoscope 100.

[0048] Gas supply line 240b and lens cleaning supply line 245b are fluidly connected to valve position 135 for gas / water valve 140 and are configured such that operation of the gas / water valve in the well controls the supply of gas or lens cleaning to the distal end 100c of endoscope 100. Suction supply line 250b is fluidly connected to valve position 135 for suction valve 145 and is configured such that operation of suction valve 145 in the well controls suction applied to the working channel 235 of endoscope 100.

[0049] Figure 3 and Figures 3A to 3C An example of a removable gas / water valve 300 is shown. The valve cover 302 includes an air vent 304 and a spring member 306. The valve stem 308 includes a central cavity 310 connected to the air vent 304 and an air inlet 312.

[0050] Valve 300 is inserted into valve body 330, as described above, and Figure 1 and Figure 2 The position 135 shown is one of them. The valve body 330 is sized and shaped to receive the valve stem 308 of the valve 300, as well as alternative valve designs (including each of those shown and described below). The valve body 330 includes an air inlet passage 332 communicating with an air source, as described above with respect to gas supply line 240a. An air outlet passage 334 similarly communicates with gas supply line 240b.

[0051] Figure 3A The diagram shows the valve in its open configuration when the air outlet 304 is not blocked, with air passing through the air inlet 312, moving upwards along the central cavity 310, and being discharged into the room. Figure 3B A second configuration of the valve is shown, in which the air vent 304 is blocked. In some embodiments, a user may place a finger on the vent 304. In other embodiments, a flap or other means for placement on the air vent 304 may also be included. When the air vent 304 is blocked, air alternatively flows through a path defined by the external recess 314 of the valve stem 308 and the internal sidewalls of the valve body 330. The air passes through the air inlet passage 332, through the air outlet passage 334, and into the endoscope for the described blowing.

[0052] Three seals 320a-c surround the valve stem 308 along its length. Each seal includes one or two scraper flanges configured to impede fluid flow when stationary without hindering vertical movement of the valve 300 within the valve body 330. The upper seal 320a is positioned below the valve cover 302 and above the external recess 314, thereby impeding flow in the valve well above the air outlet passage 334. The middle seal 320b intersects the external recess 314 of the valve stem 308, but when the valve 300 is in position... Figure 3A and Figure 3B The upper position shown does not obstruct airflow. The lower seal 320c includes two scraper flanges.

[0053] The valve body 330, at its lowest position in the valve well, also includes a water inlet passage 336 connected to the water supply and a water outlet passage 338 connected to the water supply pipeline. When the valve 300 is in... Figure 3A and Figure 3B When in the upper position, the lower one of the two scraper flanges of the lower seal 320c is above the water inlet passage 336, thereby preventing water from traveling upward along the valve well or entering the water outlet passage 338.

[0054] Figure 3C A third configuration is shown in which valve 300 is located in the lower part of valve body 330. A downward force on valve cover 302 causes and maintains this position; when valve cover 302 is released, spring member 306 returns valve 300 to its previous position. In this configuration, the outer recess 314 is no longer aligned with air inlet 332 and air outlet 334 in valve body 330. Middle seal 320b is positioned along the inner wall of valve body 330 to prevent airflow above air inlet 334. In this configuration, the two scraper flanges of lower seal 320c are located above water outlet passage 338 and below water inlet passage 336, thereby forming an annular passage between valve stem 308 and valve body 330, through which water can flow from water inlet passage 336 to water outlet passage 338. When the downward force is released and valve cover 302 returns to its previous position, the placement of lower seal 320c again prevents additional water from entering the supply line through this annular passage. Figure 3D The upper portion of valve 300 is shown, wherein cover 302 is mated to valve body 330 via spring member 306. As shown, spring member 306 is a wire coil spring that pushes valve body 330 to raise valve 300 to the upper position.

[0055] The valve stem 308 can be coupled to the cover 302 in any suitable manner. In some cases, a portion of the valve stem 308 extending proximally from the air port 304 (e.g., the proximal portion) can be coupled to the cover 302 via one or more suitable coupling mechanisms. Examples of suitable coupling mechanisms include, but are not limited to, adhesives, threaded connections, Luer lock connections, snap-fit ​​connections, ball-and-socket connectors, friction fits, and / or additional or alternative coupling mechanisms.

[0056] The valve stem 308 may have any suitable configuration for adjusting its position within the valve well, adjusting to the flow path of air and water supply and feed, and connecting to the cover 302.

[0057] Valve 300 can be manufactured in any suitable manner. In some cases, although not essential, valve 300 may be manufactured using molding, injection molding, casting, finishing, polishing, and / or one or more additional or alternative manufacturing techniques. In one exemplary example, valve 300 may be manufactured using injection molding.

[0058] The valve stem 308 may be made of a first material, and the seals 302a-c may be made of a second material; wherein the second material may be the same as or different from the first material. The valve stem 308 may be made of a rigid or hard polymer, and the seals 302a-c may be made of a flexible polymer material, but this is not mandatory. The valve stem 308 will typically be made of a polymer, acrylonitrile-butadiene-styrene (ABS), or polycarbonate. Alternatively, the valve stem 308 may be made of steel or aluminum. The seals 320a-c may be made of one or more of polymers, thermoplastic elastomers (TPE), thermoplastic polyurethanes (TPU), liquid silicone rubber (LSR), and / or other suitable materials.

[0059] The material of seals 320a-c can have any suitable hardness value. In one example, the material of seals 320a-c, when formed on valve stem 308, can have a hardness value in the range of about 20 to 80 Shore A, about 30 to 60 Shore A, and / or other suitable values ​​in one or more other suitable hardness value ranges; however, it can be softer or harder depending on the geometry of the seal and the amount of interference required for the inner wall of valve body 330. In one example, seals 320a-c can be made of silicone resin with a hardness value in the range of 40 to 50 Shore A, but this is not mandatory.

[0060] In this specification, we define “degradation” as the physical and / or chemical changes that occur to a component over time due to exposure to the environment. Weathering, corrosion, and decomposition are three common examples of degradation.

[0061] Steel and aluminum are commonly chosen as materials for mechanical devices due to their durability and resistance to degradation. Furthermore, certain alloys of steel and / or aluminum are often preferred over other alloys due to their excellent resistance to degradation.

[0062] Alternatively, metals can be selected to have particularly high degradation rates, meaning they will degrade within a shorter timeframe under the same conditions. Magnesium, zinc, and iron alloys are known to decompose more rapidly and have therefore been used as biodegradable materials for temporary insertion into the human body. Their higher degradation rates also make alloys of these metals good candidates for reducing the environmental impact of disposable components. Both metallic and non-metallic materials with high degradation rates are considered "degradable" materials.

[0063] The degradation properties of Mg, Zn, and Fe, and their respective alloys, have been investigated. A discussion of these materials can be found in Li et al., “Advances in Biodegradable Metals,” Progress in Natural Sciences: Materials International (Vol. 24 (2014), pp. 414-422), the full text of which is incorporated herein by reference. Other alloys are known to those skilled in the art.

[0064] Regarding magnesium, the degradation rates of pure magnesium and its alloys (such as Mg-Zn-Mn, Mg-Ca, Mg–Sr, Mg–Si, Mg–Zr, AZ91D, AZ31, LAE442, and WE43) make them suitable, in part or in whole, alternatives to slower-degrading materials, as well as other alloys currently known in the art or those to be discovered in the future with similar properties.

[0065] Regarding iron, the degradation rates of alloys (such as Fe–3C, Fe–3S, Fe–3W, Fe–10Mn, Fe–10Mn–1Pd, Fe–30Mn (forged), Fe–30Mn (cast), Fe–30Mn–1C, and Fe–30Mn–6Si) make them, in part or in whole, suitable alternatives to slower-degrading materials, as well as other alloys currently known in the art or future alloys with similar properties.

[0066] Regarding zinc, the degradation rates of pure zinc and its alloys (such as Zn-Mg, Zn-Mg-Ca, Zn-Mg-Sr, Zn-Al, Zn-Mn, Zn-Ca, Zn-Sr, and Zn-Ag) make them suitable alternatives, in whole or in part, to slower-degrading materials, as well as other alloys currently known in the art or future alloys with similar properties.

[0067] Returning to the valve 300 described and illustrated above, in some embodiments, the valve stem 308 may be made of a biodegradable metal. The differences in hardness, stiffness, and elasticity between the biodegradable metal alloy and steel or aluminum will not significantly impair the function of the valve stem 308 as described above. Regarding the selected alloy, if the degradation rate upon exposure to water exceeds an acceptable range for a specific surgical or usage period, the surface of the valve stem 308 may be coated with another material, such as a biodegradable polymer. In some embodiments, PHA or similar bio-based hydrocarbon polymers may be used.

[0068] In some embodiments, the spring member 306 may be made of a biodegradable material, which may be a biodegradable metal as described above, or a biodegradable polymer. In some embodiments, the biodegradable spring member may have significantly lower strength and / or modulus compared to steel wire; therefore, different geometries of the member can be used.

[0069] Degradable spring rods, wave washer assemblies, and disc washer assemblies are described. These spring components can be used with degradable materials that are less malleable than steel and more difficult to manufacture into helical springs, or where helical springs or similar structures made of degradable materials would not have a sufficient spring constant to allow for easy valve operation. For example, helical springs made of degradable thermoplastics may not have a sufficient spring constant to allow the valve to move continuously as required, while degradable thermoplastic spring rods provide sufficient force. As another example, degradable ferroalloys may be insufficiently malleable for standard techniques to be manufactured into helical springs; however, degradable ferroalloys can be effectively riveted into disc washers. Each spring component can be molded, stamped, tooled, stretched, rolled, cut, and / or any manufacturing technique or combination thereof suitable for the material and structure.

[0070] Figure 4A and Figure 4B A biodegradable spring member in the form of a spring rod 406 is shown. Multiple spring rods 406 may be arranged around the circumference of a cover 302. Like other types of spring members, the spring rods 406 may be attached to or attached to the cover 302 in various ways known in the art. When the valve 300 moves downward against the valve body 330, the spring rods 406 may flex, thereby pushing upward to return the valve 300 to its upper position. The spring rods 406 may be made of biodegradable polymers, such as thermoplastics with a high degradation rate. The spring rods 406 may also be made of magnesium, zinc, or iron alloys, or any other biodegradable metal.

[0071] Figure 5A and Figure 5BA biodegradable spring member in the form of a wave washer assembly 506 is shown. The wave washer assembly 506 may be made of multiple wave washers of similar shape, but when the assembly is compressed, the upper and lower portions of the wave are offset to contact and provide a base for the restoring force. Pressing down on the valve cover 302 compresses the wave washer assembly 506, and when released, the wave washer assembly 506 applies an upward force to the cover 302 to move the valve 300 back to the upper position. The wave washer assembly 506 may be made of a biodegradable polymer, such as a thermoplastic with a high degradation rate. The assembly 506 may also be made of magnesium, zinc, or iron alloys, or any other biodegradable metal.

[0072] Figure 6A and Figure 6B A biodegradable spring member in the form of a disc washer assembly 606 is shown. The disc washer assembly 606 may be made of multiple disc washers, each of which is similarly shaped as a truncated cone or truncated sphere (sometimes referred to as a "Belleville" washer). The stacked disc washers provide a combined spring force, which is substantially linear and is the sum of the individual spring forces of the washers. Pressing down on the valve cover 302 compresses the disc washer assembly 606, and when released, the disc washer assembly 606 applies an upward force to the cover 302, causing the valve 300 to move back to the upper position. The disc washer assembly 606 may be made of a biodegradable polymer, such as a thermoplastic with a high degradation rate. The assembly 606 may also be made of magnesium, zinc, or iron alloys, or any other biodegradable metal. The total diameter of the washers, the distance by which the inner diameter of each washer rises to form the truncated cone shape, and the corresponding angle of each washer above the horizontal plane can be selected according to the properties of the biodegradable material and the requirements of the resulting valve.

[0073] It should be understood that this disclosure is illustrative in many respects. Variations may be made in detail without departing from the scope of this disclosure, particularly concerning the arrangement of shapes, dimensions, and steps. Where appropriate, this may include using any feature used in one exemplary embodiment in other embodiments. Of course, the scope of the invention is defined by the language of the appended claims.

Claims

1. A valve assembly for a medical device, comprising: The valve body has an air inlet passage, an air outlet passage, a water inlet passage, and a water outlet passage; The valve cover located above the valve body; A spring member located between the valve cover and the valve body applies an upward force against the valve cover when the valve cover is pushed downward relative to the valve body. and A valve stem, connected to the valve cover and configured to translate between an upper and a lower position within the valve body, includes a sidewall and a central cavity extending from an air inlet in the sidewall of the valve stem to an air hole in the valve cover. The valve stem is integrally made of a biodegradable metal.

2. The valve assembly of claim 1, wherein the degradable metal comprises Mg.

3. The valve assembly according to claim 2, wherein the degradable metal is pure Mg or a Mg alloy having a higher degradation rate than pure Mg.

4. The valve assembly of claim 1, wherein the biodegradable metal comprises Zn.

5. The valve assembly according to claim 2, wherein the degradable metal is pure Zn or a Zn alloy having a higher degradation rate than pure Zn.

6. The valve assembly of claim 1, wherein the degradable metal comprises Fe.

7. The valve assembly according to claim 2, wherein the degradable metal is an Fe alloy having a higher degradation rate than pure Fe.

8. The valve assembly according to any one of claims 1 to 7, wherein the spring member is made entirely of a biodegradable metal.

9. A valve assembly for a medical device, comprising: The valve body has an air inlet passage, an air outlet passage, a water inlet passage, and a water outlet passage; A valve cover located on top of the valve body; A spring member, the spring member being made entirely of a biodegradable material, is positioned between the valve cover and the valve body such that when the valve cover is pushed downward relative to the valve body, the spring member applies an upward force against the valve cover; and A valve stem connected to the valve cover and configured to translate between an upper and a lower position within the valve body, the valve stem including a sidewall and a central cavity extending from an air inlet in the sidewall of the valve stem to an air hole in the valve cover.

10. The valve assembly according to claim 9, wherein the spring member is a spring rod.

11. The valve assembly of claim 9, wherein the spring member is a wave washer assembly.

12. The valve assembly of claim 9, wherein the spring member is a disc washer assembly.

13. The valve assembly according to any one of claims 9 to 12, wherein the degradable material comprises at least one of Mg, Zn and Fe.

14. The valve assembly according to claim 13, wherein the degradable material is pure Mg, a Mg alloy having a higher degradation rate than pure Mg, pure Zn, a Zn alloy having a higher degradation rate than pure Zn, or an Fe alloy having a higher degradation rate than pure Fe.

15. The valve assembly according to any one of claims 9 to 14, wherein the valve stem is integrally made of a biodegradable metal.

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