Patent Description:
Infusion IV sets are generally used in infusion therapy in order to deliver medication from a pre-filled container, e.g., an IV bottle or bag containing the desired medication, to a patient. Generally, the IV tubing is connected to a catheter and inserted into the localized area to be treated.

Patients are commonly injected with IV solutions that are initially provided in the IV bottle or bag and dripped into the vein of the patient through an IV line. Typically, an injection port is provided along the IV line and adapted to function with a syringe to permit an injectate to be added to the IV solution. A check valve is also commonly included in the IV line to permit fluid flow only in the direction of the patient. This ensures that the injectate flows downstream toward the patient, not upstream toward the IV reservoir.

In order to check for patency of conventional check valves, the IV line currently has to be opened in order to access and examine the check valve.

<CIT> discloses a check valve comprising two rigid body members which cooperate to provide a valve chamber with generally opposed inlet and outlet passageways. One of the body members defines a concave seating surface surrounding the inlet passageway and the other member defines the outlet passageway and an abutment structure confronting but spaced from the center of the concave seating surface. A normally flat elastomeric valve disk, smaller than the seating surface, is located between that surface and the abutment structure, which flexes or dishes the disk to maintain its periphery in sealing contact with the seating surface. Fluid pressure against the face of the disk engaged by the abutment structure increases its sealing engagement with the seating surface, but pressure on the opposite disc face overcomes the resiliency of the disk and allows fluid to flow around its periphery to the outlet passageway.

<CIT> discloses a one-way check valve in an IV system set with structural features to capture contaminant particles and inhibit the particles from adversely impacting the performance of the check valve. A screen can be provided upstream of the valve seat and the valve may be provided with flow channels for accumulating the particles. Modifications of the valve seat provide open volumes for accumulating contaminants.

<CIT> discloses an apparatus to visually indicate a leak from a relief valve are disclosed. In one example, an apparatus is disclosed that includes a pipe plug having a head and a shaft. The pipe plug is to attach to a relief valve. An opening is to extend through the head and shaft. The apparatus also includes a first flexible membrane to cover an end of the opening. In some examples, the first flexible membrane is to expand when fluid is released via the relief valve into the opening of the pipe plug.

The invention lies in the check valve of claim <NUM>, with further embodiments given in the dependent claims.

According to various embodiments of the present disclosure, a check valve includes an upper housing defining an inlet of the check valve, a lower housing comprising a support portion and defining an outlet of the check valve, and a chamber interposed between and defined by the upper and lower housings for fluidly connecting the inlet and the outlet. The check valve further includes a flexible diaphragm mounted in the chamber to selectively permit fluid flow in a first direction, and prevent fluid backflow in a second direction opposite to the first direction. The flexible diaphragm includes a color changing material, in which when the flexible diaphragm is seated on the support portion and bent due to force of the fluid flowing in the first direction, the flexible diaphragm exhibits a color change.

According to various aspects of the present disclosure, a check valve includes a valve chamber comprising an inlet port at an inlet end, an outlet port at an outlet end, and an internal surface defining a ceiling and convex-shaped sidewalls of the chamber. The check valve further includes a flexible diaphragm supported within the valve chamber. The flexible diaphragm includes a plurality of layers of transparent material which exhibits a color change when the flexible diaphragm is seated in the valve chamber and bent due to force of the fluid flowing from the inlet port to the outlet port.

The following figures are included to illustrate certain aspects of the embodiments, and should not be viewed as exclusive embodiments. The subject matter disclosed is capable of considerable modifications, alterations, combinations, and equivalents in form and function, as will occur to those skilled in the art and having the benefit of this disclosure.

The present description relates in general to check valves, and more particularly, for example and without limitation, to check valves capable of changing color to visually indicate patency when subject to pressure from fluid flow.

In accordance with 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 between and defined by the upper and lower housings for fluidly connecting 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 to prevent fluid backflow (reverse flow) from the outlet to the inlet.

In some embodiments, the flexible diaphragm is in the form of a disc or any other circular plate and may be formed of a color changing material. When the flexible diaphragm is seated on a support portion of the lower housing and bent or bowed due to pressure of the fluid flowing in the direction from the inlet to the outlet, the flexible diaphragm may change color. Structurally, the flexible diaphragm is formed of a plurality of stacked layers of transparent material. When the flexible diaphragm is exposed to an upstream pressure (i.e., a pressure applied by a fluid flowing from the inlet to the outlet), the flexible diaphragm bends, bows, or is otherwise deformed such that light reflects off each interface between adjacent layers of the flexible diaphragm. The reflected light produces colors in the visible spectrum on the flexible diaphragm that may be observed by a user/caregiver as an indication of fluid flow, thereby signaling patency of the check valve.

In some embodiments, the upper housing includes an internal surface defining sidewalls of the chamber. The sidewalls have a convex shape which acts as a magnifying lens and allows for the color change of the flexible diaphragm to be magnified and more easily viewable.

Advantageously, due to the convex-shaped structure of the inner walls of the upper housing forming a magnifying lens, the color change of the flexible diaphragm can be easily viewed from the exterior without having to open the fluid line. The color change indicates patency of the check valve and may 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 a net upstream pressure (thereby indicating there is flow through the check valve) by simply observing the visual color change of the flexible diaphragm. As such, the need for a separate pressure sensor to confirm fluid flow is removed.

<FIG> illustrates an IV extension set that includes a check valve <NUM>, in accordance with some embodiments of the present disclosure. As depicted, IV set <NUM> includes a primary fluid system <NUM> and a secondary fluid system <NUM>. An IV pump (not shown) receives fluid from primary fluid system <NUM> and secondary fluid system <NUM> via a primary IV line <NUM> and may control and dispense the fluids therefrom to a patient <NUM>.

In some embodiments, primary fluid system <NUM> includes a primary fluid source such as a primary fluid bag <NUM> which may include or contain saline solution or other medicinal fluid or drug to be administered to the patient <NUM>. As illustrated, primary IV line <NUM> carries primary fluid from a drip chamber <NUM> to check valve <NUM>. As shall be described further with respect to the following figures, check valve <NUM> is disposed in primary IV line <NUM> and allow fluid flow from primary fluid bag <NUM> to the IV pump (not illustrated) while preventing reverse flow (backflow) of fluid from secondary fluid system <NUM> toward primary fluid bag <NUM>. In accordance with some embodiments, secondary fluid system <NUM> includes secondary fluid source such as a secondary fluid bag <NUM>, which contains drugs or other secondary fluid to be supplied to the patient <NUM> for treatment. As depicted, the IV set <NUM> further includes a secondary IV line <NUM> which carries flow from drip chamber <NUM> to the check valve <NUM>.

<FIG> illustrates a cross-sectional view of a check valve in an open state, in accordance with some embodiments of the present disclosure. Referring to <FIG>, the check valve <NUM> includes an axially extending body <NUM> defining a central longitudinal axis X. In some embodiments, the body <NUM> is formed of a chemical resistant material which may have magnifying properties. The body <NUM> is formed of a material capable of providing superior light transmittance and clarity. For example, in some embodiments, the material of the body is formed of an acrylic polymer. The body <NUM> is a generally cylindrical (or tubular) structure and may include an upper housing <NUM> and a lower housing <NUM>. The upper housing <NUM> includes a first end portion <NUM> and an axially opposite second end portion <NUM>. As illustrated, a radial extent of the upper housing <NUM> at the second end portion <NUM> is greater than the radial extent thereof at the first end portion <NUM>. The lower housing <NUM> includes an upstream internal surface <NUM>, and the second end portion <NUM> and the upstream internal surface <NUM> of the lower housing <NUM> axially contact each other to co-operatively form a chamber <NUM> of the check valve <NUM>.

In some embodiments, the upper housing <NUM> includes an inlet <NUM> of the check valve <NUM> at the first end <NUM>, and the lower housing <NUM> may include an outlet <NUM> of the check valve <NUM>. The body <NUM> defines an internal flow passage <NUM> axially extending between the inlet <NUM> and the outlet <NUM> and in fluid communication therewith. As is understood, the check valve <NUM> permits fluid to flow from the inlet <NUM> to the outlet <NUM> (as indicated by the arrows in <FIG>), and minimize, or otherwise limit, fluid flow from the outlet <NUM> to the inlet <NUM> (as indicated by the arrows in <FIG>). As depicted, the upper housing <NUM> and the lower housing <NUM> define the chamber <NUM> for fluidly connecting the inlet <NUM> and the outlet <NUM>.

<FIG> illustrates a cross-sectional view of a check valve coupled to a male luer, in accordance with some embodiments of the present disclosure. <FIG> illustrates a cross-sectional view of the check valve of <FIG> along line <NUM>-<NUM>, in accordance with some embodiments of the present disclosure. The check valve <NUM> of the various embodiments described herein is positioned at different locations on the IV set <NUM>, depending on the desired purpose. For example, in some embodiments the check valve <NUM> is positioned below the drip chamber <NUM> to prevent any potential backflow into the primary IV line <NUM>. In some embodiments, as depicted in <FIG>, the check valve <NUM> is built into or otherwise coupled to a connector, e.g., male luer connector <NUM> at the end of the IV set, closer to the patient <NUM>. When coupled to the connector <NUM>, the check valve <NUM> is used to prevent backflow of the patient's blood into the IV set <NUM>.

In the depicted embodiments, a flexible diaphragm <NUM> is mounted in the chamber <NUM> to selectively permit fluid flow from the inlet <NUM> to the outlet <NUM>, and prevent fluid backflow (reverse flow) from the outlet <NUM> to the inlet <NUM>.

In accordance with some embodiments, the flexible diaphragm <NUM> is in the form of a disc or any other circular plate. As depicted, the flexible diaphragm <NUM> is mounted on a support portion <NUM> of the lower housing <NUM>. In particular, the support portion <NUM> includes a central aperture <NUM> and a plurality of axially extending slots <NUM> through which fluid flowing from the inlet <NUM> and into the cavity <NUM> may enter the outlet <NUM> in the open state of the check valve <NUM>.

As depicted, the flexible diaphragm <NUM> is formed of a color changing material. As referred to herein a color changing material is defined as a material that, when subject to an axial load, is capable of reflecting light to exhibit vibrant colors in the visible spectrum. Accordingly, when the flexible diaphragm <NUM> is seated on the support portion <NUM> and bent due to force of the fluid flowing in the direction from the inlet <NUM> to the outlet <NUM>, the flexible diaphragm <NUM> changes or otherwise exhibits color. In particular, in some embodiments, the flexible diaphragm <NUM> is formed of a plurality of layers of transparent material. For example, the flexible diaphragm <NUM> is formed of a plurality of ultrathin layers of the transparent materials, which are periodically stacked to form the disc-shaped flexible diaphragm <NUM>. In some embodiments, each layer of transparent material within the disc-shaped flexible diaphragm is on the order of a few hundred nanometers thick. In some embodiments, the transparent material is a transparent rubber material or any other similar material capable of bending or otherwise deforming under a load.

In some embodiments, the flexible diaphragm <NUM> is formed of a resistive pressure sensing material having a hollow sphere microstructure such as, but not limited to an elastic, micro-structured conducting polymer thin film material.

In some embodiments, the flexible diaphragm <NUM> is formed of a tactile pressure indicating sensor film. In yet other embodiments, the flexible diaphragm <NUM> is formed of a material having hollow spheres in its structure, where the hollow spheres are pressed together under pressure, causing the flexible diaphragm <NUM> to change color.

In some embodiments, the upper housing <NUM> includes an internal surface having a first portion defining a ceiling <NUM> and a second portion defining sidewalls <NUM> of the chamber <NUM>. As depicted, the portion of the internal surface defining the sidewalls <NUM> has a convex shape. Additionally, in embodiments herein -a the sidewalls <NUM> are formed of a transparent material to allow for visual observation of the color change. Advantageously, the convex shape of the sidewalls <NUM> acts as a magnifying lens and allows for the color change of the flexible diaphragm <NUM> to be magnified and more easily observed.

In operation, when the flexible diaphragm <NUM> formed of the plurality of transparent layers is exposed to an upstream fluid pressure (i.e., a pressure applied by a fluid flowing from the inlet <NUM> to the outlet <NUM>), the flexible diaphragm <NUM> bends, bows or be otherwise deformed such that light reflects off each interface between adjacent layers of the flexible diaphragm. The reflected light produces colors in the visible spectrum on the flexible diaphragm <NUM> that dependents on the geometric properties and material composition of the transparent layers of the flexible diaphragm <NUM>. For example, with layers of consistent thickness, the light reflected off the interfaces between the adjacent layers of the flexible diaphragm <NUM> interacts to strengthen some colors in the visible spectrum, for example red, while diminishing the brightness of other colors. Accordingly, when bent due to the upstream fluid pressure, the flexible diaphragm <NUM> formed of transparent layers appears or otherwise exhibits a certain color, depending on the thickness of the layers within the flexible diaphragm <NUM>.

In accordance with various embodiments, the flexible diaphragm <NUM> is formed of a pressure sensing material. For example, the flexible diaphragm <NUM> is made of a plurality of layered pressure-sensing photonic fibers such that when subject to the upstream pressure, for a specific desired pressure, the fibers of the flexible diaphragm <NUM> reflect an easily distinguished color. To this effect, the flexible diaphragm <NUM> is designed such that it changes color when the fluid flow from the inlet port to the outlet port exerts a pressure normal to the flexible diaphragm that is greater than or equal to a predetermined threshold pressure.

Accordingly, various embodiments of the present disclosure provide a check valve <NUM> having a flexible diaphragm <NUM> that changes color when bent, bowed, or otherwise deformed due to an upstream fluid pressure that is oriented substantially perpendicularly or normal to the flexible diaphragm <NUM>. The upstream pressure causes the flexible diaphragm <NUM> to bend or bow outwards towards the outlet <NUM>. As depicted, the flexible diaphragm <NUM> bows outwards most at a central portion thereof where the fluid pressure is most concentrated or stronger. Once the flexible diaphragm <NUM> is bent or bowed while seated on the support portion <NUM>, light reflects off each interface between adjacent layers of the flexible diaphragm <NUM>. The reflected light produces colors in the visible spectrum on the flexible diaphragm <NUM>.

In some embodiments, as illustrated in the figures, the color change is most intense at a central portion of the flexible diaphragm where the fluid pressure is most concentrated and become less intense towards the outer periphery of the flexible diaphragm <NUM>. For example, a caregiver sees different colors of different intensities depending on the magnitude of the upstream fluid pressure.

Advantageously, due to the convex-shaped structure of the inner walls <NUM> of the upper housing <NUM> which form a magnifying lens, the color change of the flexible diaphragm <NUM> can be easily viewed from the exterior without having to open the fluid line. The color change indicates patency of the check valve <NUM> and may confirm to the user or caregiver that fluid is actually flowing through the check valve <NUM> as intended. Further advantageously, the user or caregiver can confirm that there is a net upstream pressure (thereby indicating there is flow through the check valve <NUM>) by simply observing the visual color change of the flexible diaphragm <NUM>. As such, the need for a separate pressure sensor to confirm fluid flow is obviated.

<FIG> illustrates a cross-sectional view of a check valve <NUM> in a closed state, in accordance with some embodiments of the present disclosure. As depicted, and as previously described above, the upper housing <NUM> includes an internal surface having a first portion defining a ceiling <NUM> and a second portion defining sidewalls <NUM> of the chamber <NUM>. In some embodiments, the ceiling <NUM> defines a sealing surface of the check valve <NUM>. As illustrated in <FIG>, in the closed state of the check valve <NUM>, the flexible diaphragm <NUM> contacts the ceiling <NUM>. Because the flexible diaphragm <NUM> contacts the internal surface defining the ceiling <NUM>, reverse flow (backflow) of fluid from the outlet <NUM> to the inlet <NUM> is restricted or prevented.

During operation, when a downstream pressure (i.e., a pressure applied by a fluid flowing from the outlet <NUM> to the inlet <NUM>) is applied to the flexible diaphragm <NUM>, the flexible diaphragm <NUM> may be moved towards and contact the ceiling <NUM> to block fluid communication between the inlet <NUM> and the chamber <NUM>, thereby restricting backflow of the fluid from the outlet <NUM> into the inlet <NUM>. Preventing or restricting backflow of the fluid is advantageous in that it restricts undesirable particulate matter, for example, contained in a drug dispensed from a secondary path from flowing back through the flexible diaphragm <NUM>, thereby preventing the patient from receiving the proper drug dosage concentration or from timely delivery of the drug.

In one or more embodiments of the disclosure, a check valve comprises an upper housing defining an inlet of the check valve; a lower housing comprising a support portion and defining an outlet of the check valve; a chamber interposed between and defined by the upper and lower housings for fluidly connecting the inlet and the outlet; and a flexible diaphragm mounted in the chamber to selectively permit fluid flow in a first direction, and prevent fluid backflow in a second direction opposite to the first direction, the flexible diaphragm comprising a color changing material, wherein when the flexible diaphragm is seated on the support portion and bent due to force of the fluid flowing in the first direction, the flexible diaphragm exhibits a color change.

In aspects of the disclosure, the flexible diaphragm comprises a plurality of periodically stacked layers of a transparent material. In aspects of the disclosure, the upper housing comprises an internal surface having a first portion defining a ceiling and a second portion defining sidewalls of the chamber; and the portion of the internal surface defining the sidewalls of the chamber comprises a convex shape. In aspects of the disclosure, the sidewalls having the convex shape comprise a transparent material to allow for visual observation of the color change. In aspects of the disclosure, the convex shape of the sidewalls forms a magnifying material to enhance visual observation of the color change.

In aspects of the disclosure, the flexible diaphragm comprises a disc shape. In aspects of the disclosure, the flexible diaphragm comprises a pressure sensor. In aspects of the disclosure, the flexible diaphragm comprises pressure-sensing photonic fibers. In aspects of the disclosure, the flexible diaphragm changes color when the fluid flow in the first direction that has a pressure greater than or equal to a predetermined pressure. In aspects of the disclosure, the flexible diaphragm changes color when subject to a compressive force oriented substantially perpendicular to the flexible diaphragm. In aspects of the disclosure, the flexible diaphragm comprises a transparent rubber material.

In one or more embodiments of the disclosure, a check valve comprises a valve chamber comprising an inlet port at an inlet end, an outlet port at an outlet end, and an internal surface defining a ceiling and convex-shaped sidewalls of the chamber; and a flexible diaphragm supported within the valve chamber, wherein the flexible diaphragm comprises a plurality of layers of transparent material which exhibits a color change when the flexible diaphragm is seated in the valve chamber and bent due to force of the fluid flowing from the inlet port to the outlet port.

In aspects of the disclosure, the convex-shaped sidewalls comprise a transparent material to allow for visual observation of the color change. In aspects of the disclosure, the convex shape of the sidewalls forms a magnifying material to enhance visual observation of the color change. In aspects of the disclosure, the flexible diaphragm comprises a disc shape. In aspects of the disclosure, the flexible diaphragm comprises a pressure sensor. In aspects of the disclosure, the flexible diaphragm comprises pressure-sensing photonic fibers. In aspects of the disclosure, the flexible diaphragm changes color when the fluid flow from the inlet port to the outlet port is greater than or equal to a predetermined pressure. In aspects of the disclosure, the flexible diaphragm changes color when subject to a fluid force oriented normal to the flexible diaphragm. In aspects of the disclosure, the transparent material comprises a transparent rubber material.

Claim 1:
A check valve (<NUM>), comprising:
an upper housing (<NUM>) defining an inlet (<NUM>) of the check valve (<NUM>), sidewalls (<NUM>) of the upper housing (<NUM>) being transparent;
a lower housing (<NUM>) comprising a support portion (<NUM>) and defining an outlet (<NUM>) of the check valve (<NUM>);
a chamber (<NUM>) interposed between and defined by the upper and lower housings (<NUM>, <NUM>) for fluidly connecting the inlet (<NUM>) and the outlet (<NUM>); and
a flexible diaphragm (<NUM>) mounted in the chamber (<NUM>) to selectively permit fluid flow in a first direction, and prevent fluid backflow in a second direction opposite to the first direction,
characterized by the flexible diaphragm (<NUM>) comprising a color changing material, wherein when the flexible diaphragm (<NUM>) is seated on the support portion (<NUM>) and bent due to force of the fluid flowing in the first direction, the flexible diaphragm (<NUM>) exhibits a color change.