Degradable valve for endoscopes

Abstract

The present invention relates to a device, system, and method for a valve assembly (140) for a medical device (100). The valve (300) comprises a cap (302), a stem (308) that moves within a valve body (330), and a spring member (306) positioned between the cap and the valve body to move the valve within the body. The valve stem (308) and / or spring member (306) are made from a degradable material, which may be metallic. The degradable material has a higher degradation rate than conventional metallic valve components to reduce the environmental impact of valve disposal.

Description

[Technical Field]

[0001] The present disclosure generally relates to valve assemblies and methods, and more particularly to supply valve assemblies and methods for endoscopes. [Background Art]

[0002] A wide variety of in-vivo medical devices and systems have been developed for medical uses, for example, for endoscopic procedures. Some of these devices and systems include guidewires, catheters, catheter systems, endoscopic instruments, and the like. These devices and systems can be manufactured by any one of a variety of different manufacturing methods and can be used in accordance with any one of a variety of methods. Each of the known medical devices, systems, and methods has certain advantages and disadvantages.

[0003] Some medical devices include components that are "single-use", which are intended to be discarded after a short period of time such as one day or one procedure. These disposable components are often classified as biological waste, thus contributing significantly to the environmental costs associated with procedures. When a component is made of steel or another resilient material, the time and / or energy required to decompose the component can be significant. There is a need for medical device components that decompose more easily in order to reduce the overall environmental burden associated with their disposal. [Summary of the Invention]

[0004] This disclosure provides alternative designs, materials, manufacturing methods, and uses for medical devices and medical systems. In the first example, a valve assembly for a medical device [Oyama 1.1] includes a valve body having an air inlet passage, an air outlet passage, a water inlet passage, and a water outlet passage; a valve cap positioned above the valve body; a spring member positioned between the valve cap and the valve body and configured to apply an upward force to the valve cap when the valve cap is pushed downward relative to the valve body; and a valve stem connected to the valve cap and configured to move between an upper and lower position within the valve body, wherein the valve stem comprises a side wall and a central lumen extending from an air inlet in the side wall of the valve stem to an air hole in the valve cap, and the entire assembly is made of a degradable metal.

[0005] In any of the above examples, the degradable metal may, alternatively or additionally, include magnesium. The degradable metal may be pure magnesium, or an alloy of magnesium having a higher degradation rate than pure magnesium.

[0006] In any of the above examples, the degradable metal may, alternatively or additionally, include zinc. The degradable metal may be pure zinc, or an alloy of zinc having a higher degradation rate than pure zinc.

[0007] In any of the above examples, the degradable metal may, alternatively or additionally, include iron. The degradable metal may be an alloy of iron that degrades at a higher rate than pure iron. In any of the above examples, the spring component may, alternatively or additionally, be made entirely from a degradable metal.

[0008] In another example, a valve assembly for a medical device includes a valve body having an air inlet passage, an air outlet passage, a water inlet passage, and a water outlet passage; a valve cap positioned above the valve body; a spring member, entirely made of a degradable material, positioned between the valve cap and the valve body and configured to apply an upward force to the valve cap when the valve cap is pushed downward relative to the valve body; and a valve stem connected to the valve cap and configured to move between an upper and lower position within the valve body, wherein the valve stem comprises a side wall and a central lumen extending from an air inlet in the side wall of the valve stem to an air hole in the valve cap.

[0009] In any of the above examples, the spring member may, alternatively or additionally, be a spring lever. In any of the above examples, the spring member may, alternatively or additionally, be a laminate of wave washers.

[0010] In any of the above examples, the spring member may, alternatively or additionally, be a stack of disc washers. In any of the above examples, the degradable material may, alternatively or additionally, include at least one of magnesium, zinc, and iron.

[0011] In any of the above examples, the degradable material may, alternatively or additionally, be pure magnesium or an alloy of magnesium having a higher degradation rate than pure magnesium, or pure zinc or an alloy of zinc having a higher degradation rate than pure zinc, or an alloy of iron having a higher degradation rate than pure iron.

[0012] In any of the above examples, the valve stem may, alternatively or additionally, be made entirely from a degradable metal. These features and advantages of the present disclosure, and other features and advantages, will be readily apparent from the following detailed description, and the scope of the claimed invention is defined in the appended claims. [Brief explanation of the drawing]

[0013] The accompanying drawings, incorporated into and constituting parts of this specification, illustrate various embodiments and, together with the specification, illustrate the principles of this disclosure. [Figure 1] Figure 1 shows a schematic diagram of the components of an exemplary endoscope. [Figure 2] Figure 2 shows a schematic diagram of the components of an exemplary endoscopic system. [Figure 3] Figure 3 shows a perspective view of an equivalent supply valve. [Figure 3A] Figure 3A shows a schematic cross-sectional view of an exemplary supply valve in which the valve is in the first configuration. [Figure 3B] Figure 3B shows a schematic cross-sectional view of an exemplary supply valve in which the valve is in the second configuration. [Figure 3C] Figure 3C shows a schematic cross-sectional view of an exemplary supply valve in which the valve is in the third configuration. [Figure 3D] Figure 3D shows a schematic cross-sectional view of the top of an exemplary supply valve having a spring member. [Figure 4A] Figure 4A shows a perspective view of an equivalent spring member. [Figure 4B] Figure 4B shows a schematic cross-sectional view of the upper part of an exemplary supply valve having the spring member shown in Figure 4A. [Figure 5A] Figure 5A shows a perspective view of an equivalent spring member. [Figure 5B] Figure 5B shows a schematic cross-sectional view of the upper part of an exemplary supply valve having the spring member shown in Figure 5A. [Figure 6A] Figure 6A shows a perspective view of an equivalent spring member. [Figure 6B] Figure 6B shows a schematic cross-sectional view of the top of an exemplary supply valve having the spring member shown in Figure 6A.

[0014] While various modifications and alternative forms can be made to the present disclosure, specific embodiments thereof are shown by way of example in the drawings and will be described in detail below. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternative forms falling within the spirit and scope of the present disclosure. MODE FOR CARRYING OUT THE INVENTION

[0015] The present disclosure will now be described with reference to exemplary medical systems that may be used in endoscopic medical procedures. It should be noted, however, that the reference to this specific procedure is provided for convenience only and is not intended to limit the present disclosure. Those skilled in the art will recognize that the concepts underlying the disclosed devices and related methods of use may be utilized in any suitable procedure, whether medical or otherwise. The present disclosure may be understood with reference to the following description and the accompanying drawings, in which like elements are referred to by the same reference numerals.

[0016] All numerical values herein, whether explicitly indicated or not, shall be deemed to be modified by the term "about". In the context of numerical values, the term "about" generally means a range of numerical values that a person skilled in the art would consider substantially equivalent to the stated value (e.g., a range having the same function or result). In many cases, the term "about" may include numerical values rounded to the nearest significant figure. Unless otherwise specified, other usages of the term "about" (e.g., usage in contexts other than numerical values) may be considered to have ordinary and conventional definitions understood from and consistent with the context of the present specification.

[0017] A description of a numerical range with endpoints includes all numerical values within the range including the endpoints (for example, 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5). Although some suitable dimensions, ranges and / or values regarding various components, features and / or specifications are disclosed, those skilled in the art contemplated by the present disclosure will understand that the desired dimensions, ranges and / or values may deviate from those explicitly disclosed herein.

[0018] As used in the present specification and the appended claims, the singular forms "a", "an" and "the" are intended to include plural referents unless the content clearly dictates otherwise. As used in the present specification and the appended claims, the term "or" is generally intended to be used in the sense that includes "and / or", unless the content clearly dictates otherwise. It should be noted that, for ease of understanding, certain features of the present disclosure may be described in the singular form even if such features may exist in multiples or repeatedly within the disclosed embodiments. Unless explicitly stated to the contrary, each instance of such a feature is included in and / or encompassed by the singular disclosure. For purposes of brevity and clarity, not all elements of the present disclosure are necessarily illustrated in each drawing or discussed in detail below. However, it will be understood that unless explicitly stated to the contrary, the following description is equally applicable to any and / or all components that exist in plural. Furthermore, for clarity, not all instances of certain elements or features are shown in each drawing.

[0019] References in this specification to “certain embodiments,” “some embodiments,” and “other embodiments” indicate that the embodiments described may include certain features, structures, or characteristics, but it should be noted that not all embodiments necessarily include those specific features, structures, or characteristics. Furthermore, such expressions do not necessarily refer to the same embodiments. Moreover, when certain features, structures, or characteristics are described in relation to an embodiment, it should be within the knowledge of those skilled in the art to realize those features, structures, or characteristics in relation to other embodiments, whether or not they are explicitly described, unless otherwise explicitly stated. In other words, the various individual elements described below, even if not explicitly shown in a particular combination, are still intended to be combined or arranged in a manner understandable to those skilled in the art to form other additional embodiments or to complement and / or enhance the embodiments described.

[0020] For the purpose of clarity, specific identifying numerical names (e.g., 1st, 2nd, 3rd, 4th, etc.) may be used throughout the specification and / or claims to name and / or distinguish the various features described and / or claimed. These numerical names should be understood as illustrative only and not limiting. In some embodiments, changes and deviations from conventionally used numerical names may be made for brevity and clarity. That is, a feature identified as the "1st" element may subsequently be referred to as the "2nd" element, the "3rd" element, and so on, or may be omitted entirely, and / or a different feature may be referred to as the "1st" element. The meaning and / or designation in each case will be obvious to those skilled in the art.

[0021] The detailed description is intended to illustrate the disclosure and not to limit it. Those skilled in the art will recognize that the various elements described may be arranged in various combinations and configurations without departing from the scope of the disclosure. The detailed description illustrates exemplary embodiments of the disclosure.

[0022] Referring to Figure 1, an exemplary endoscope 100 is shown, and Figure 2 shows an exemplary endoscope system 200. The endoscope 100 may include a long tube or shaft 100a configured to be inserted into a subject (e.g., a patient).

[0023] The light source 205 of the endoscope system 200 can supply illumination light to the distal end 100b of the endoscope 100. The distal end 100b of the endoscope 100 may house an imager (e.g., a CCD or CMOS imager) (not shown). The light source 205 (e.g., a lamp) may be located within a video processing unit 210 that processes the signal input from the imager and outputs the processed video signal to a video monitor (not shown) for observation. The video processing unit 210 may also function as a component of an air / water supply circuit by housing a pressurizing pump 215, such as an air supply pump, within the unit 210.

[0024] The endoscope shaft 100a may include a distal tip 100c (e.g., a distal tip unit) located at the distal end 100b of the shaft 100a, and a flexible bending section 105 proximal to the distal tip 100c. The flexible bending section 105 may include an articulated joint (not shown) to assist in steering the distal tip 100c. The end face 100d of the distal tip 100c of the endoscope 100 has a gas / lens cleaning nozzle 220 for supplying gas to inflate the inside of the patient in the treatment area and for supplying water to clean the lens covering the imager. An irrigation port 225 at the end face 100d supplies irrigation fluid to the patient's treatment area. An illumination window (not shown) for transmitting illumination light to the treatment area, and an opening 230 to a working channel 235 extending along the shaft 100a for passing instruments into the treatment area, may also be included on the surface 100d of the distal tip 100c. The working channel 235 may extend along the shaft 100a to a proximal channel opening 110 located distal to the operating handle 115 of the endoscope 100 (e.g., the proximal handle). A biopsy valve 120 may be used to seal the channel opening 110 to prevent unwanted fluid leakage.

[0025] The operating handle 115 may be provided with knobs 125 for remote four-way steering of the distal end via wires connected to the articulation joint of the flexible curved section 105 (for example, one knob controls up-and-down steering, and another controls left-and-right steering). Multiple video switches 130 for remotely operating the video processing unit 210 may be located on the proximal end side of the handle 115.

[0026] The handle 115 may be provided with two valve positions 135. One of the valve positions 135 may receive a gas / water valve 140 for operating the supply of expansion gas and lens water. The gas supply line 240a and the lens cleaning supply line 245a extend distally from the gas / water valve 140 along the shaft 100a and merge at the distal tip 100c, which is proximal to the gas / cleaning nozzle 220 (Figure 2).

[0027] The other valve position 135 can accommodate a suction valve 145 for activating the suction action. The suction supply line 250a may extend distally from the suction valve 145 along the shaft 100a to a junction that fluidly communicates with the working channel 235 of the endoscope 100.

[0028] The operating handle 115 can be electrically and fluidly connected to the video processing unit 210 via a flexible umbilical 260 and connector section 265 extending between them. The flexible umbilical 260 has a gas (e.g., air or CO2) supply line 240b, a lens cleaning supply line 245b, a suction supply line 250b, a perfusion supply line 255b, a light guide (not shown), and an electrical signal cable (not shown). When the connector section 265 is plugged into the video processing unit 210, it connects the light source 205 in the video processing unit to the light guide. The light guide extends along the entire length of the umbilical 260 and the endoscope shaft 100a to transmit light to the distal tip 100c of the endoscope 100. When the connector section 265 is plugged into the video processing unit 210, it also connects the air pump 215 to the gas supply line 240b in the umbilical 260.

[0029] A water reservoir or container 270 (e.g., a water bottle) may be fluidly connected to the endoscope 100 through the connector section 265 and the umbilical 260. A gas supply tube 240c of some length passes from one end positioned in the gap 275 between the top 280 of the reservoir 270 (e.g., the bottle cap) and the residual water 285 in the reservoir to a removable gas / lens cleaning connection 290 located outside the connector section 265. A gas supply line 240b from the umbilical 260 branches at the connector section 265 to fluidly communicate with the gas supply tube 240c and the air pump 215 at the removable gas / lens cleaning connection 290. A lens cleaning tube 245c of some length, with one end positioned at the bottom of the reservoir 270, may pass through the top 280 of the reservoir 270 to the same removable connection 290 as the gas supply tube 240c at the connector section 265. In other embodiments, these connections may be separate and / or isolated from one another. The connector section 265 may also have a removable perfusion connection section 293 for a perfusion supply tube (not shown) extending from a perfusion water source (not shown) to the perfusion supply line 255b of the umbilical 260. In some embodiments, the perfusion water is supplied from a water source (not shown) independent of the water reservoir 270 via a pump (e.g., a peristaltic pump). In other embodiments, the perfusion supply tube and the lens cleaning tube 245c may be supplied with water from the same reservoir. The connector section 265 may also include a removable suction connection section 295 for suction supply lines 250b and 250a, which fluidly connect a vacuum source (e.g., a hospital suction device) (not shown) to the umbilical 260 and the endoscope 100.

[0030] The gas supply line 240b and the lens cleaning supply line 245b may be fluidically connected to valve position 135 for the gas / water valve 140, and the operation of the gas / water valve in the well may be configured to control the supply of gas or lens cleaning fluid to the distal tip 100c of the endoscope 100. The suction supply line 250b is fluidically connected to valve position 135 for the suction valve 145, and the operation of the suction valve 145 in the well may be configured to control the suction applied to the working channel 235 of the endoscope 100.

[0031] An example of a removable gas / water valve 300 is illustrated in Figures 3 and 3A to 3C. The valve cap 302 includes an air vent 304 and a spring member 306. The valve stem 308 includes a central lumen 310 and an air inlet 312 connected to the air vent 304.

[0032] Valve 300 is inserted into a body 330, such as in one of the positions 135 shown in Figures 1 and 2 and described above. The body 330 may be sized and shaped to accommodate the stem 308 of 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 the gas supply line 240a. Similarly, an air outlet passage 334 communicates with the gas supply line 240b.

[0033] Figure 3A shows the valve in an open configuration, where the air outlet 304 is not blocked, and air passes through the air inlet 312, upward through the central lumen 310, and out into the chamber. Figure 3B shows a second configuration of the valve, where the air outlet 304 is blocked. In some embodiments, the user may place their finger over the hole 304. In other embodiments, a flap or other device for positioning over the air outlet 304 may also be included. When the air outlet 304 is blocked, air alternatively flows through a path defined by the outer recess 314 of the valve stem 308 and the inner side wall of the body 330. The air passes through the air inlet passage 332 and the air outlet passage 334, and enters the endoscope for use in air delivery, as described.

[0034] The three seals 320a–320c surround the valve stem 308 along their entire length, each including one or two wiper flanges configured to obstruct fluid flow when stationary without obstructing the vertical movement of the valve 300 within the body 330. The upper seal 320a is located below the valve cap 302 and above the outer recess 314, obstructing flow in the valve well above the location of the air outlet passage 334. The intermediate seal 320b intersects the outer recess 314 in the valve stem 308 but does not obstruct airflow when the valve 300 is in the upper position shown in Figures 3A and 3B. The lower seal 320c includes two wiper flanges.

[0035] The valve body 330 further includes a water inlet passage 336 connected to a water supply source and a water outlet passage 338 connected to a water supply line at the bottom of the valve well. When the valve 300 is in the upper position as shown in Figures 3A and 3B, the lower of the two wiper flanges of the lower seal 320c is located above the water inlet passage 336, preventing water from moving upward through the valve well or into the water outlet passage 338.

[0036] Figure 3C shows a third configuration in which the valve 300 is positioned lower on the body 330. A downward force on the valve cap 302 creates and maintains this position, and when the valve cap 302 is released, the spring member 306 returns the valve 300 to its previous position. In this configuration, the outer recess 314 is no longer aligned with the air inlet passage 332 and the air outlet passage 334 of the valve body 330. The intermediate seal 320b is positioned along the inner wall of the body 330 and obstructs the airflow above the air inlet passage 334. The two wiper flanges of the lower seal 320c are positioned above the water outlet passage 338 and below the water inlet passage 336 in this configuration, forming an annular passage between the valve stem 308 and the valve body 330 through which water can flow from the water inlet passage 336 to the water outlet passage 338. When the downward force is released and the valve cap 302 returns to its previous position, the arrangement of the lower seal 320c again prevents additional water from entering the supply section through the annular passage. Figure 3D shows the upper part of the valve 300 where the cap 302 is connected to the valve body 330 by a spring member 306. As shown, the spring member 306 is a coil spring of steel wire that pushes the valve body 330 and lifts the valve 300 to an upward position.

[0037] The valve stem 308 can be coupled to the cap 302 in any suitable manner. In some cases, a portion of the valve stem 308 extending proximal to the air vent 304 (e.g., the proximal portion) can be coupled to the cap 302 via one or more suitable coupling mechanisms. Examples of suitable coupling mechanisms include, but are not limited to, adhesives, screw connections, Luer lock connections, snap connections, ball detent connectors, friction fits, and / or additional or alternative coupling mechanisms.

[0038] The valve stem 308 may have any suitable configuration configured to adjust its position within the valve well, adjust the flow paths to the air and water supply sources and supply sections, and connect to the cap 302.

[0039] The valve 300 may be formed in any suitable manner. In some cases, the valve 300 may be formed by, or using, a molding process, an injection molding process, a casting process, a finishing process, polishing, and / or one or more additional or alternative manufacturing techniques, although this is not essential. In one exemplary example, the valve 300 may be formed using an injection molding process.

[0040] The valve stem 308 may be formed from a first material, and the seals 320a-320c may be formed from a second material, where the second material may be the same as or different from the first material. The valve stem 308 may be formed from a rigid or stiff polymer, and the seals 320a-320c may be formed from a flexible polymer, although this is not mandatory. The valve stem 308 will typically be formed from a polymer, acrylonitrile butadiene styrene (ABS), or polycarbonate. Alternatively, the valve stem 308 may be formed from steel or aluminum. The seals 320a-320c may be formed from one or more of the following materials: polymer, thermoplastic elastomer (TPE), thermoplastic polyurethane (TPU), liquid silicone rubber (LSR), and / or other suitable materials.

[0041] The material of seals 320a-320c may have any suitable durometer value. In one example, the material of seals 320a-320c when formed on the valve stem 308 may have any other suitable durometer value within the range of about 20-80 Shore A, about 30-60 Shore A, and / or one or more other suitable durometer values, but may be softer or harder depending on the geometric structure used for the seal and the desired amount of interference with the inner wall of the valve body 330. In one example, seals 320a-320c may be formed from silicone having a durometer value in the range of 40-50 Shore A, but this is not required.

[0042] In this specification, “degradation” is defined as the physical and / or chemical changes of a component that occur over time due to its exposure to the environment. Weathering, corrosion, and decomposition are three common examples of degradation.

[0043] Steel and aluminum are frequently chosen as materials for mechanical devices due to their long lifespan and resistance to degradation. Furthermore, certain alloys of steel and / or aluminum are often preferred over other alloys due to their superior resistance to degradation.

[0044] However, as an alternative, metals may be selected to have a particularly high degradation rate, meaning that the metal will degrade in a shorter period of time in the same environment. Magnesium, zinc, and iron alloys are known to decompose more quickly 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 nonmetallic materials with higher degradation rates are considered "degradable" materials.

[0045] The degradation properties of magnesium, zinc, and iron, as well as their respective alloys, have been studied. Much of the discussion of these materials is found in Li et al., "Progress of biodegradable metals," Progress in Natural Science: Materials International 24(2014)414-422, which is incorporated herein by reference in its entirety. Other alloys are known to those skilled in the art.

[0046] With respect to magnesium, the degradation rates of pure magnesium and alloys such as Mg-Zn-Mn, Mg-Ca, Mg-Sr, Mg-Si, Mg-Zr, AZ91D, AZ31, LAE442, and WE43, along with some or all of them, can be suitable substitutes for slower-degrading materials, along with other alloys currently known in the art, or later alloys with similar properties.

[0047] With respect to iron, the degradation rates of alloys such as Fe-3C, Fe-3S, Fe-3W, Fe-10Mn, Fe-10Mn-1Pd, Fe-30Mn (forged), Fe30Mn (cast), Fe-30Mn-1C, and Fe-30Mn-6Si, along with some or all of them, may be suitable substitutes for slower-degrading materials, along with other alloys currently known in the art, or later alloys with similar properties.

[0048] With respect to zinc, the degradation rates of pure zinc and alloys such as Zn-Mg, Zn-Mg-Ca, Zn-Mg-Sr, Zn-Al, Zn-Mn, Zn-Ca, Zn-Sr, and Zn-Ag, along with some or all of them, can serve as suitable substitutes for slower-degrading materials, along with other alloys currently known in the art, or later alloys with similar properties.

[0049] Returning to the valve 300 described and illustrated above, in some embodiments the valve stem 308 may be made from a degradable metal. The differences in hardness, stiffness, and elasticity of the degradable metal alloy compared to those of steel or aluminum will not substantially hinder the function of the stem 308 as described above. For the alloy of choice, if the rate of degradation upon exposure to water is faster than acceptable for a particular treatment or service life, the surface of the valve stem 308 may be coated with another substance, such as a degradable polymer. In some embodiments, PHA or similar bio-based hydrocarbon polymers may be used.

[0050] In some embodiments, the spring member 306 may be made from a degradable material, which may be a degradable metal as described above, or a degradable polymer. In some embodiments, the degradable spring member may have significantly lower strength and / or modulus than steel wire. Therefore, different geometric structures may be used for the member.

[0051] Degradable spring levers, wave washer laminates, and disc washer laminates are described below. These spring members may be used with degradable materials that are less ductile than steel and more difficult to manufacture as coil springs, or when coil springs or similar structures made from degradable materials do not have a sufficient spring constant to allow for the smooth operation of a valve. For example, a coil spring made from a degradable thermoplastic material may not have a sufficient spring constant to move a valve stably as required, while a spring lever made from a degradable thermoplastic material provides sufficient force. As another example, a degradable iron alloy may not be ductile enough to be formed into a coil spring using standard techniques, but that degradable iron alloy can be efficiently fixed into a disc washer. Each spring member may be manufactured by forming, pressing, tooling, drawing, rolling, cutting, and / or by any manufacturing technique or combination thereof appropriate to its material and structure.

[0052] Figures 4A and 4B show a degradable spring member in the form of a spring lever 406. Multiple spring levers 406 may be included circumferentially around the cap 302. As with other forms of spring members, the spring lever 406 may be attached to or fixed to the cap 302 in various manners known in the art. The spring lever 406 may flex when the valve 300 moves downward against the valve body 330 and may press upward to return the valve 300 to its upper position. The spring lever 406 may be made from a degradable polymer such as a thermoplastic resin having a high degradation rate. The spring lever 406 may also be made from a magnesium, zinc, or iron alloy, or any other degradable metal.

[0053] Figures 5A and 5B show a degradable spring member in the form of a wave washer laminate 506. The wave washer laminate 506 may be made from multiple wave washers of similar shape, but the upper and lower portions of the wave are offset so that they come into contact when the laminate is compressed to provide the basis for a restoring force. Downward pressure on the valve cap 302 compresses the wave washer laminate 506, and when released, the wave washer laminate 506 exerts an upward force on the cap 302, returning the valve 300 to its upper position. The wave washer laminate 506 may be made from a degradable polymer such as a thermoplastic resin with a higher degradation rate. The laminate 506 may also be made from magnesium, zinc, or iron alloys, or any other degradable metal.

[0054] Figures 6A and 6B show a degradable spring member in the form of a disc washer laminate 606. The disc washer laminate 606 may be made from a plurality of disc washers, each disc washer having a shape similar to a frustocone or sphere (sometimes referred to as a "Belleville" washer). The laminated disc washers provide a substantially linear composite spring force, which is the sum of the individual spring forces of the washers. Downward pressure on the valve cap 302 compresses the disc washer laminate 606, and when released, the disc washer laminate 606 exerts an upward force on the cap 302, returning the valve 300 to its upper position. The disc washer laminate 606 may be made from a degradable polymer, such as a thermoplastic resin, which has a higher degradation rate. The laminate 606 may also be made from an alloy of magnesium, zinc, or iron, or any other degradable metal. The overall diameter of the washer, the distance by which the inner diameter of the washer is lifted to form a frustocone, and the corresponding angle of each washer with respect to the horizontal plane can be selected according to the properties of the degradable material and the requirements of the resulting valve.

[0055] It should be understood that this disclosure is illustrative in many respects. Detailed modifications may be made without exceeding the scope of this disclosure, particularly in terms of shape, size, and step arrangement. This includes, to an appropriate extent, using any feature of one exemplary embodiment in other embodiments. Naturally, the scope of the invention is defined in the language set forth in the appended claims.

Claims

1. A valve body having an air inlet passage, an air outlet passage, a water inlet passage, and a water outlet passage, A valve cap positioned above the valve body, A spring member disposed between the valve cap and the valve body, configured to apply an upward force to the valve cap when the valve cap is pushed downward relative to the valve body, A valve stem connected to the valve cap and configured to move between an upper position and a lower position within the valve body, the valve stem comprising a side wall and a central lumen extending from an air inlet in the side wall of the valve stem to an air hole in the valve cap, the entire valve stem being made of a degradable metal, Valve assembly for medical devices.

2. The aforementioned degradable metal includes magnesium, The valve assembly according to claim 1.

3. The aforementioned degradable metal is pure magnesium or a magnesium alloy having a higher degradation rate than pure magnesium. The valve assembly according to claim 2.

4. The aforementioned degradable metal includes zinc, The valve assembly according to claim 1.

5. The aforementioned degradable metal is pure zinc or a zinc alloy having a higher degradation rate than pure zinc. The valve assembly according to claim 2.

6. The aforementioned degradable metal includes iron, The valve assembly according to claim 1.

7. The aforementioned degradable metal is an iron alloy that has a higher degradation rate than pure iron. The valve assembly according to claim 2.

8. The aforementioned spring member is made entirely from a degradable metal. The valve assembly according to any one of claims 1 to 7.

9. A valve body having an air inlet passage, an air outlet passage, a water inlet passage, and a water outlet passage, A valve cap positioned above the valve body, A spring member made entirely of a degradable material, positioned between the valve cap and the valve body, and configured to apply an upward force to the valve cap when the valve cap is pushed downward relative to the valve body, A valve stem connected to the valve cap and configured to move between an upper position and a lower position within the valve body, the valve stem comprising a side wall and a central lumen extending from an air inlet in the side wall of the valve stem to an air hole in the valve cap, Valve assembly for medical devices.

10. The aforementioned spring member is a spring lever. The valve assembly according to claim 9.

11. The spring member is a laminate of wave washers. The valve assembly according to claim 9.

12. The spring member is a stack of disc washers. The valve assembly according to claim 9.

13. The aforementioned degradable material includes at least one of magnesium, zinc, and iron. The valve assembly according to any one of claims 9 to 12.

14. The aforementioned degradable material is pure magnesium, or a magnesium alloy having a higher degradation rate than pure magnesium, or pure zinc, or a zinc alloy having a higher degradation rate than pure zinc, or an iron alloy having a higher degradation rate than pure iron. The valve assembly according to claim 13.

15. The valve stem is entirely made from a degradable metal. The valve assembly according to any one of claims 9 to 14.

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