Color changing and pressure sensing check valve

Abstract

To provide a valve member of a check valve that can change color to visually indicate patency when subjected to pressure from a fluid flow.SOLUTION: The check valve includes an upper housing defining an inlet of the check valve and a lower housing having a support and defining an outlet of the check valve. The check valve further includes a chamber defined interposed between the upper housing and the lower housing for fluidly connecting the inlet and the outlet, and a flexible diaphragm attached to the chamber. The flexible diaphragm selectively permits fluid flow in a first direction and prevents backflow of fluid in a second direction opposite the first direction. The flexible diaphragm includes a color changing material such that when the flexible diaphragm is mounted to the support and flexed by the force of fluid flowing in a first direction, the flexible diaphragm exhibits a color change.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates generally to check valves, and more particularly to a valve member of a check valve that can change color to visually indicate patency when subjected to pressure from a fluid flow. [Background technology]

[0002] Infusion IV sets are generally used in infusion therapy to deliver medication to a patient from a pre-filled container, such as an IV bottle or bag, containing the desired medication. Generally, the IV tubing is connected to a catheter and inserted into the local area to be treated.

[0003] Patients are typically injected with IV solutions that are initially provided in an IV bottle or bag and dripped into the patient's vein through an IV line. An injection port is typically provided along the IV line and adapted to function with a syringe so that the injection solution can be added to the IV solution. A check valve is also typically included in the IV line to allow fluid flow only in the direction of the patient, ensuring that the injection solution flows downstream toward the patient and not upstream toward the IV reservoir.

[0004] To check the patency of a conventional check valve, the IV line currently must be opened to access and inspect the check valve.

[0005] The statements provided in the Background Art section should not be assumed to be prior art merely because they are mentioned in or associated with the Background Art section. The Background Art section may include information that describes one or more aspects of the subject technology. Summary of the Invention [Means for solving the problem]

[0006] According to various embodiments of the present disclosure, a check valve may include an upper housing defining an inlet of the check valve, a lower housing including a support and defining an outlet of the check valve, and a chamber interposed and defined between the upper and lower housings to fluidly connect the inlet and the outlet. The check valve may further include a flexible diaphragm attached to the chamber to selectively permit fluid flow in a first direction and prevent backflow of fluid in a second direction opposite the first direction. The flexible diaphragm may include a color-changing material, and when the flexible diaphragm is mounted to the support and bent by a force of fluid flowing in the first direction, the flexible diaphragm exhibits a color change.

[0007] According to various aspects of the present disclosure, a check valve may include a valve chamber including an inlet port at an inlet end, an outlet port at an outlet end, and an interior surface defining a ceiling and a convex sidewall of the chamber. The check valve may further include a flexible diaphragm supported within the valve chamber. The flexible diaphragm may include multiple layers of transparent material that exhibit a color change when the flexible diaphragm is seated in the valve chamber and flexes due to the force of fluid flowing from the inlet port to the outlet port.

[0008] It is understood that other configurations of the subject technology will be readily apparent to those skilled in the art from the following detailed description, wherein various configurations of the subject technology are shown and described by way of example. As will be realized, the subject technology is capable of other different configurations, and its several details can be modified in various other respects without departing from the scope of the subject technology. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive.

[0009] The following figures are included to illustrate certain aspects of the embodiments and should not be viewed as exclusive examples. The disclosed subject matter is capable of considerable modification, alteration, combination, and equivalents in form and function, as will occur to those skilled in the art and having the benefit of this disclosure. [Brief explanation of the drawings]

[0010] [Figure 1] 1 illustrates an IV extension set including a check valve, according to some embodiments of the present disclosure. [Figure 2] 1 illustrates a cross-sectional view of a check valve in an open state, according to some embodiments of the present disclosure. [Figure 3] 1 shows a cross-sectional view of a check valve coupled to a male luer, according to some embodiments of the present disclosure. [Figure 4] 4 illustrates a cross-sectional view of a check valve taken along line 4-4 of FIG. 3, according to some embodiments of the present disclosure. [Figure 5] 1 illustrates a cross-sectional view of a check valve in a closed state, according to some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] The detailed description set forth below describes various configurations of the subject technology and is not intended to represent the only configurations in which the subject technology may be practiced. The detailed description includes specific details intended to provide a thorough understanding of the subject technology. Thus, dimensions may be provided for particular embodiments as non-limiting examples. However, it will be apparent to those skilled in the art that the subject technology may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form to avoid obscuring the concepts of the subject technology.

[0012] It should be understood that the present disclosure includes examples of the subject technology and does not limit the scope of the appended claims. Various aspects of the subject technology are disclosed herein by way of specific, but non-limiting, examples. The various embodiments described in the present disclosure may be implemented in different ways and with modifications according to the desired application or implementation.

[0013] The present description relates generally to check valves and more particularly to check valves that can change color to visually indicate patency when subjected to pressure from, for example, but not by way of limitation, a fluid flow.

[0014] According to some embodiments, a check valve includes an upper housing defining an inlet of the check valve, a lower housing defining an outlet of the check valve, and a chamber interposed and defined between the upper and lower housings to fluidly connect the inlet and the outlet. A flexible diaphragm may be mounted in the chamber to selectively permit fluid flow from the inlet to the outlet and prevent reverse flow of fluid from the outlet to the inlet.

[0015] In some embodiments, the flexible diaphragm may be in the form of a disk or any other circular plate and may be formed of a color-changing material. When the flexible diaphragm is mounted to a support in the lower housing and bent or bowed by the pressure of fluid flowing in a direction from the inlet to the outlet, the flexible diaphragm may change color. Structurally, the flexible diaphragm may be formed of multiple stacked layers of transparent material. When the flexible diaphragm is exposed to upstream pressure (i.e., pressure exerted by fluid flowing from the inlet to the outlet), the flexible diaphragm bends, bows, or otherwise deforms such that light is reflected at each interface between adjacent layers of the flexible diaphragm. The reflected light creates a color in the visible spectrum on the flexible diaphragm that is observed by the user / caregiver as an indication of fluid flow, thereby indicating the patency of the check valve.

[0016] In some embodiments, the upper housing includes an inner surface that defines a sidewall of the chamber, and the sidewall may have a convex shape that acts as a magnifying lens, magnifying and making the color change of the flexible diaphragm more easily visible.

[0017] Advantageously, due to the convex structure of the inner wall of the upper housing that forms a magnifying lens, the color change of the flexible diaphragm can be easily seen from the outside without opening the fluid line. The color change indicates the patency of the check valve and can confirm to the user or caregiver that fluid is actually flowing through the check valve as intended. Further advantageously, the user or caregiver can confirm that there is net upstream pressure (thereby indicating flow through the check valve) by simply observing the visual color change of the flexible diaphragm. This eliminates the need for a separate pressure sensor to confirm fluid flow.

[0018] 1 illustrates an IV extension set including a check valve 100, according to some embodiments of the present disclosure. As shown, the IV set 1 includes a primary fluid system 11 and a secondary fluid system 25. An IV pump (not shown) may receive fluid from the primary fluid system 11 and the secondary fluid system 25 via a primary IV line 5 and control and distribute the fluid therefrom to a patient 50.

[0019] In some embodiments, primary fluid system 11 may include a primary fluid source, such as primary fluid bag 10, which contains or contains saline, other medical fluid, or medication to be administered to patient 50. As shown, primary IV line 5 carries the primary fluid from drip chamber 13 to check valve 100. As further described with respect to the following figures, check valve 100 may be disposed in primary IV line 5 to allow fluid flow from primary fluid bag 10 to an IV pump (not shown) while preventing reverse flow of fluid from secondary fluid system 25 toward primary fluid bag 10. According to some embodiments, secondary fluid system 25 includes a secondary fluid source, such as secondary fluid bag 20, which contains medication or other secondary fluid to be delivered to patient 50 for treatment. As shown, IV set 1 may further include secondary IV line 7, which carries flow from drip chamber 22 to check valve 100.

[0020] FIG. 2 illustrates a cross-sectional view of a check valve in an open state, according to some embodiments of the present disclosure. Referring to FIG. 2 , check valve 100 may include an axially extending body 101 defining a central longitudinal axis X. In some embodiments, body 101 may be formed of a chemically resistant material that may have expansion properties. Body 101 may be formed of a material that can provide excellent light transmission and transparency. For example, in some embodiments, the body material may be formed of an acrylic polymer. Body 101 may be a generally cylindrical (or tubular) structure and may include an upper housing 10 and a lower housing 15. Upper housing 10 may include a first end 12 and an axially opposed second end 14. As illustrated, the radial extent of upper housing 10 at second end 14 may be greater than its radial extent at first end 12. The lower housing 15 may include an upstream inner surface 16, and the second end 14 and the upstream inner surface 16 of the lower housing 15 may be in axial contact with each other to cooperatively form the chamber 30 of the check valve 100.

[0021] In some embodiments, the upper housing 10 may include the inlet 20 of the check valve 100 at the first end 12, and the lower housing 15 may include the outlet 25 of the check valve 100. The body 101 may define an internal passage 18 extending axially between and in fluid communication with the inlet 20 and the outlet 25. As will be appreciated, the check valve 100 may allow fluid to flow from the inlet 20 to the outlet 25 (as shown by the arrows in FIG. 2 ) and minimize or otherwise restrict fluid flow from the outlet 25 to the inlet 20 (as shown by the arrows in FIG. 5 ). As depicted, the upper housing 10 and the lower housing 15 may define a chamber 30 to fluidly connect the inlet 20 and the outlet 25.

[0022] FIG. 3 shows a cross-sectional view of a check valve coupled to a male luer according to some embodiments of the present disclosure. FIG. 4 shows a cross-sectional view of a check valve along line 4-4 of FIG. 3 according to some embodiments of the present disclosure. The check valve 100 of various embodiments described herein may be positioned in different locations on the IV set 1 depending on the desired purpose. For example, in some embodiments, the check valve 100 may be positioned below the drip chamber 13 to prevent any potential backflow into the primary IV line 5. In some embodiments, as depicted in FIG. 3, the check valve 100 may be incorporated into or otherwise coupled to a connector at the end of the IV set closer to the patient 50, such as a male luer connector 23. When coupled to the connector 23, the check valve 100 may be used to prevent the backflow of the patient's blood into the IV set 1.

[0023] In the depicted embodiment, flexible diaphragm 35 may be attached to chamber 30 to selectively allow fluid flow from inlet 20 to outlet 25 and prevent reverse flow of fluid from outlet 25 to inlet 20.

[0024] According to some embodiments, flexible diaphragm 35 may be in the form of a disk or any other circular plate. As depicted, flexible diaphragm 35 may be attached to support 28 of lower housing 14. In particular, support 28 may include a central opening 44 and a plurality of axially extending slots 46 through which fluid entering cavity 30 from inlet 20 can enter outlet 25 when check valve 100 is in an open state.

[0025] As depicted, flexible diaphragm 35 may be formed of a color-changing material. As referred to herein, a color-changing material is defined as a material that can reflect light to exhibit vibrant colors in the visible spectrum when subjected to an axial load. Thus, when flexible diaphragm 35 is mounted to support 28 and bent by the force of fluid flowing in a direction from inlet 20 to outlet 25, flexible diaphragm 35 changes color or otherwise exhibits color. Notably, in some embodiments, flexible diaphragm 35 may be formed of multiple layers of transparent material. For example, flexible diaphragm 35 may be formed of multiple ultra-thin layers of transparent material, which may be periodically stacked to form disk-shaped flexible diaphragm 35. In some embodiments, each layer of transparent material in the disk-shaped flexible diaphragm may be on the order of several hundred nanometers thick. In some embodiments, the transparent material may be a transparent rubber material or any other similar material that can bend or otherwise deform under load.

[0026] In some embodiments, flexible diaphragm 35 may be formed of a resistive pressure sensitive material having a hollow sphere microstructure, such as, but not limited to, an elastic, microstructured conductive polymer thin film material.

[0027] In some embodiments, flexible diaphragm 35 may be formed of a tactile pressure-indicating sensor membrane. In yet other embodiments, flexible diaphragm 35 may be formed of a material that has hollow spheres in its structure that can be pressed together under pressure to cause flexible diaphragm 35 to change color.

[0028] In some embodiments, upper housing 10 includes an interior surface having a first portion that defines ceiling 40 of chamber 30 and a second portion that defines sidewall 42. As depicted, the portion of the interior surface that defines sidewall 42 may have a convex shape. Additionally, in some embodiments, sidewall 42 is formed of a transparent material to allow visual observation of the color change. Advantageously, the convex shape of sidewall 42 acts as a magnifying lens, allowing the color change of flexible diaphragm 35 to be magnified and more easily observed.

[0029] In operation, when flexible diaphragm 35 formed of multiple transparent layers is subjected to upstream fluid pressure (i.e., pressure exerted by fluid flowing from inlet 20 to outlet 25), flexible diaphragm 35 may bend, bow, or otherwise deform such that light reflects at each interface between adjacent layers of the flexible diaphragm. The reflected light produces colors in the visible spectrum on flexible diaphragm 35, which may depend on the geometric properties and material composition of the transparent layers of flexible diaphragm 35. For example, with layers of consistent thickness, light reflected at interfaces between adjacent layers of flexible diaphragm 35 may interact to enhance some colors in the visible spectrum, such as red, while reducing the brightness of other colors. Thus, when bent by upstream fluid pressure, flexible diaphragm 35 formed of transparent layers may appear or otherwise exhibit a certain color, depending on the thickness of the layers within flexible diaphragm 35.

[0030] In various embodiments, flexible diaphragm 35 may be formed of a pressure-sensitive material. For example, flexible diaphragm 35 may be made of multiple layers of pressure-sensitive photonic fiber such that, when subjected to upstream pressure, the fibers of flexible diaphragm 35 reflect an easily identifiable color for a specified desired pressure. To this effect, flexible diaphragm 35 may be designed to change color when fluid flow from the inlet port to the outlet port exerts a pressure perpendicular to the flexible diaphragm above a predetermined threshold pressure.

[0031] Accordingly, various embodiments of the present disclosure provide a check valve 100 having a flexible diaphragm 35 that changes color when bent, bowed, or otherwise deformed by upstream fluid pressure oriented generally perpendicular or perpendicular to the flexible diaphragm 35. The upstream pressure causes the flexible diaphragm 35 to bend or bow outward toward the outlet 25. As depicted, the flexible diaphragm 35 may bow most outward at its center, where the fluid pressure is most concentrated or strongest. As the flexible diaphragm 35 is bent or bowed when mounted to the support 28, light reflects off each interface between adjacent layers of the flexible diaphragm 35. The reflected light produces colors in the visible spectrum on the flexible diaphragm 35.

[0032] In some embodiments, as shown, the color change may be strongest at the center of the flexible diaphragm where the fluid pressure is most concentrated, and weaker toward the periphery of the flexible diaphragm 35. For example, a caregiver may see different colors of different intensities depending on the amount of upstream fluid pressure.

[0033] Advantageously, due to the convex structure of the inner wall 42 of the upper housing 10 forming a magnifying lens, the color change of the flexible diaphragm 35 can be easily viewed from the outside without opening the fluid line. The color change indicates the patency of the check valve 100 and may confirm to a user or caregiver that fluid is indeed flowing through the check valve 100 as intended. Further advantageously, a user or caregiver can confirm that there is net upstream pressure (thereby indicating flow through the check valve 100) simply by observing the visual color change of the flexible diaphragm 35. This eliminates the need for a separate pressure sensor to confirm fluid flow.

[0034] FIG. 5 shows a cross-sectional view of a check valve 100 in a closed state, according to some embodiments of the present disclosure. As depicted and as described above, the upper housing 10 may include an inner surface having a first portion that defines the ceiling 40 of the chamber 30 and a second portion that defines the sidewall 42. In some embodiments, the ceiling 40 defines a sealing surface of the check valve 100. As shown in FIG. 5 , in the closed state of the check valve 100, the flexible diaphragm 35 contacts the ceiling 40. Because the flexible diaphragm 35 contacts the inner surface that defines the ceiling 40, reverse flow of fluid from the outlet 25 to the inlet 20 is restricted or prevented.

[0035] During operation, when downstream pressure (i.e., pressure exerted by fluid flowing from outlet 25 to inlet 20) is applied to flexible diaphragm 35, flexible diaphragm 35 may move toward and contact ceiling 40, obstructing fluid communication between inlet 20 and chamber 30 and thereby restricting the backflow of fluid from outlet 25 into inlet 20. Preventing or restricting the backflow of fluid is advantageous, for example, in restricting undesirable particulate matter contained in medication dispensed from the secondary pathway from flowing back through flexible diaphragm 35 and thereby preventing a patient from receiving a concentrated dose of the appropriate medication or preventing the timely delivery of the medication.

[0036] In one or more embodiments of the present disclosure, the check valve includes an upper housing defining an inlet of the check valve, a lower housing including a support and defining an outlet of the check valve, a chamber interposed and defined between the upper and lower housings to fluidly connect the inlet and the outlet, and a flexible diaphragm attached to the chamber to selectively allow fluid flow in a first direction and prevent backflow of fluid in a second direction opposite the first direction, the flexible diaphragm including a color-changing material, and when the flexible diaphragm is mounted on the support and bent by the force of fluid flowing in the first direction, the flexible diaphragm exhibits a color change.

[0037] In an embodiment of the present disclosure, the flexible diaphragm includes multiple periodically stacked layers of transparent material. In an embodiment of the present disclosure, the upper housing includes an inner surface having a first portion defining a ceiling of the chamber 30 and a second portion defining a sidewall, the portion of the inner surface defining the sidewall of the chamber having a convex shape. In an embodiment of the present disclosure, the sidewall having a convex shape includes a transparent material to enable visual observation of the color change. In an embodiment of the present disclosure, the convex shape of the sidewall forms a magnifying material to enhance visual observation of the color change.

[0038] In an embodiment of the present disclosure, the flexible diaphragm has a disk shape. In an embodiment of the present disclosure, the flexible diaphragm includes a pressure sensor. In an embodiment of the present disclosure, the flexible diaphragm includes a pressure-sensing photonic fiber. In an embodiment of the present disclosure, the flexible diaphragm changes color when a fluid flow in a first direction has a pressure equal to or greater than a predetermined pressure. In an embodiment of the present disclosure, the flexible diaphragm changes color when subjected to a compressive force oriented substantially perpendicular to the flexible diaphragm. In an embodiment of the present disclosure, the flexible diaphragm includes a transparent rubber material.

[0039] In one or more embodiments of the present disclosure, a check valve includes a valve chamber including an inlet port at an inlet end, an outlet port at an outlet end, an inner surface defining a ceiling of the chamber and a convex-shaped sidewall of the chamber, and a flexible diaphragm supported within the valve chamber, the flexible diaphragm including multiple layers of transparent material that exhibits a color change when the flexible diaphragm is seated in the valve chamber and is bent by the force of fluid flowing from the inlet port to the outlet port.

[0040] In an embodiment of the present disclosure, the convex-shaped sidewall comprises a transparent material to allow visual observation of the color change. In an embodiment of the present disclosure, the convex shape of the sidewall forms a magnifying material to enhance visual observation of the color change. In an embodiment of the present disclosure, the flexible diaphragm has a disk shape. In an embodiment of the present disclosure, the flexible diaphragm comprises a pressure sensor. In an embodiment of the present disclosure, the flexible diaphragm comprises a pressure-sensing photonic fiber. In an embodiment of the present disclosure, the flexible diaphragm changes color when fluid flow from the inlet port to the outlet port exceeds a predetermined pressure. In an embodiment of the present disclosure, the flexible diaphragm changes color when subjected to a fluid force oriented perpendicular to the flexible diaphragm. In an embodiment of the present disclosure, the transparent material comprises a transparent rubber material.

[0041] This disclosure is provided to enable those skilled in the art to practice the various aspects described herein. While this disclosure provides various illustrative examples of the subject technology, the subject technology is not limited to these examples. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects.

[0042] Reference to an element in the singular is not intended to mean "only one" but rather "one or more" unless specifically stated otherwise. The term "some" refers to one or more unless specifically stated otherwise. Masculine pronouns (e.g., his) include the feminine and neuter genders (e.g., her and its), and vice versa. Headings and subheadings, if any, are used merely for convenience and do not limit the invention.

[0043] The word "exemplary" is used herein to mean "serving as an example or illustration." Any aspect or design described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects or designs. In one aspect, various alternative configurations and operations described herein are construed as at least equivalent.

[0044] As used herein, the phrase "at least one of," preceding a list of items, along with the word "or" separating any of the items, modifies the list as a whole rather than each item in the list. The phrase "at least one of," does not require the selection of at least one item; rather, the phrase allows for a meaning including at least one of any of the items, and / or at least one of any combination of the items, and / or at least one of each of the items. By way of example, the phrase "at least one of A, B, or C" may refer to A only, B only, or C only, or any combination of A, B, and C.

[0045] The use of a phrase such as "aspect" does not imply that the aspect is essential to the subject technology or that the aspect applies to all configurations of the subject technology. Disclosure of one aspect may apply to all configurations, or to one or more configurations. An aspect may provide one or more examples. A phrase such as "aspect" may refer to one or more aspects, and vice versa. A phrase such as "embodiment" does not imply that the embodiment is essential to the subject technology or that the embodiment applies to all configurations of the subject technology. Disclosure of one embodiment may apply to all embodiments, or to one or more examples. An embodiment may provide one or more examples. A phrase such as "embodiment" may refer to one or more examples, and vice versa. A phrase such as "configuration" does not imply that the configuration is essential to the subject technology or that the configuration applies to all configurations of the subject technology. Disclosure of one configuration may apply to all configurations, or to one or more configurations. A configuration may provide one or more examples. A phrase such as a configuration may refer to one or more configurations, and vice versa.

[0046] In one aspect, unless otherwise specified, all measurements, values, estimates, locations, dimensions, sizes, and other specifications set forth herein, including those in the following claims, are approximate and not exact, and are intended to have a reasonable range consistent with the function to which they relate and that which is customary in the art to which they pertain.

[0047] It is understood that the specified order or hierarchy of steps or acts in the disclosed processes or methods is an illustration of a sample approach. Based on implementation preferences or scenarios, it is understood that the specified order or hierarchy of steps, acts, or processes may be rearranged. Some of the steps, acts, or processes may occur simultaneously. In some implementation preferences or scenarios, certain acts may or may not be performed. Some or all of the steps, acts, or processes may occur automatically, without user intervention. The accompanying method claims present elements of the various steps, acts, or processes in a sample order, and are not meant to be limited to the specified order or hierarchy presented.

[0048] All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later become known to those skilled in the art are intended to be expressly incorporated herein by reference and encompassed by the claims. Furthermore, nothing disclosed herein is intended to be a public offering, regardless of whether that disclosure is explicitly recited in the claims. No claim element is to be construed under 35 U.S.C. § 112(f) unless the element is expressly recited using the phrase "means for," or, in the case of a method claim, unless the element is recited using the phrase "step for." Furthermore, to the extent the terms "comprise," "have," and the like are used, these terms are intended to be as inclusive as the term "having" when "having" is employed as a transitional term in a claim.

[0049] The title, background, summary, brief description of the drawings, and abstract of the disclosure are hereby incorporated into this disclosure and are provided as illustrative examples of the disclosure, not as a limiting description. They are submitted with the understanding that they will not be used to limit the scope or meaning of the claims. Furthermore, in the detailed description, it will be appreciated that the description provides illustrative examples, and that various features are grouped together in various embodiments for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed subject matter requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed structure or operation. The following claims are incorporated into this more detailed description, with each claim standing on its own as separately claimed subject matter.

[0050] The claims are not intended to be limited to the embodiments described herein, but are to be accorded the full scope consistent with the claim language and encompass all legal equivalents. Nevertheless, no claim is intended to, and should not be construed to, encompass subject matter that does not comply with the requirements of 35 U.S.C. §§ 101, 102, or 103.

Claims

1. an upper housing defining an inlet of the check valve; a lower housing including a support and defining an outlet of the check valve; a chamber interposed and defined between the upper housing and the lower housing for fluidly connecting the inlet and the outlet; a flexible diaphragm attached to the chamber to selectively permit fluid flow in a first direction and prevent backflow of fluid in a second direction opposite the first direction, the flexible diaphragm comprising a color-changing material, the flexible diaphragm being mounted to the support and exhibiting a color change when bent by a force of the fluid flowing in the first direction; A check valve comprising:

2. The check valve of claim 1 , wherein the flexible diaphragm comprises a plurality of periodically stacked layers of transparent material.

3. the upper housing includes an inner surface having a first portion defining a ceiling of the chamber and a second portion defining a sidewall; The check valve of claim 1 , wherein the portion of the inner surface defining the sidewall of the chamber has a convex shape.

4. The check valve of claim 3 , wherein the sidewall having the convex shape includes a transparent material to allow visual observation of the color change.

5. The check valve of claim 4 , wherein the convex shape of the sidewall creates an enlarged area to enhance visual observation of the color change.

6. The check valve of claim 1 , wherein the flexible diaphragm has a disk shape.

7. The check valve of claim 1 , wherein the flexible diaphragm includes a pressure sensor.

8. 10. The check valve of claim 1, wherein the flexible diaphragm includes a pressure-sensing photonic fiber.

9. 10. The check valve of claim 1, wherein the flexible diaphragm changes color when the fluid flow in the first direction has a pressure equal to or greater than a predetermined pressure.

10. 10. The check valve of claim 1, wherein the flexible diaphragm changes color when subjected to a compressive force oriented generally perpendicular to the flexible diaphragm.

11. The check valve of claim 1 , wherein the flexible diaphragm comprises a transparent rubber material.

12. a valve chamber including an inlet port at an inlet end, an outlet port at an outlet end, and an interior surface defining a ceiling and a convex sidewall of the chamber; a flexible diaphragm supported within the valve chamber, the flexible diaphragm including multiple layers of transparent material that exhibits a color change when the flexible diaphragm is seated in the valve chamber and deflected by a force of fluid flowing from the inlet port to the outlet port; A check valve comprising:

13. The check valve of claim 12 , wherein the convex sidewall comprises a transparent material to allow visual observation of the color change.

14. The check valve of claim 12 , wherein the convex shape of the sidewall creates an enlarged material to enhance visual observation of the color change.

15. The check valve of claim 12 , wherein the flexible diaphragm has a disk shape.

16. 16. The check valve of claim 15, wherein the flexible diaphragm includes a pressure sensor.

17. 17. The check valve of claim 16, wherein the flexible diaphragm includes a pressure-sensitive photonic fiber.

18. 13. The check valve of claim 12, wherein the flexible diaphragm changes color when fluid flow from the inlet port to the outlet port exceeds a predetermined pressure.

19. 13. The check valve of claim 12, wherein the flexible diaphragm changes color when subjected to a fluid force directed perpendicular to the flexible diaphragm.

20. The check valve of claim 12 , wherein the transparent material comprises a transparent rubber material.

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