Check valve

A check valve is provided, including a first hose connector housing defining an entry passage and a first valve seat, a second hose connector housing engaging the first hose connector housing and defining an exit passage, a generally flexible, perforate membrane disk positioned between the first and second hose connector housings and pretensioned against the first valve seat to selectively sealingly separate the first and second hose connector housings, and a one-way relief valve fluidly connected with the exit passage and configured to permit venting of the exit passage upon overpressurization thereof.

FIELD OF THE INVENTION

This invention relates to a check valve, such as a check valve suited for medical applications.

BACKGROUND

Check valves may be used to selectively fluidly connect a first hose with a second hose. More specifically, check valves known in the art may be used to permit fluid flow in a first direction and to prevent or restrict flow in a second, opposite direction. One such known check valve includes a first hose connector housing, a second hose connector housing, and a membrane disk of flexible material positioned between the two hose connector housings. The membrane disk is selectively sealingly seated on a valve seat to selectively separate the first and second hoses from each other. Specifically, when unaffected by external forces the membrane disk is seated on the valve seat. However, when a sufficient external force acts on the membrane disk, such as fluid pressure from fluid flowing along the first hose, the membrane disk becomes unseated and permits fluid connection between the first and second hoses. More specifically, the membrane disk defines an opening that permits fluid flow therethrough when the membrane disk is unseated from the valve seat, thereby connecting the first and second hoses. Such a design is disclosed in European patent 0 612 537 and U.S. Pat. No. 5,617,897, the entire contents of each of which are incorporated herein by reference.

In some applications, such as medical applications, it may be desirable to limit pressure able to be exerted on the exit side of the check valve. However, check valves are typically designed to permit fluid travel from the entry passage to the exit passage and to prohibit travel in the opposite direction.

It is therefore desirable to provide a check valve that meets applicable standards, that is relatively simple and economical to manufacture, and that limits the maximum pressure able to be exerted on the exit side of the check valve.

BRIEF SUMMARY

This invention seeks to address the above-mentioned shortcomings of the prior art. A check valve is provided, including a first hose connector housing defining an entry passage and a first valve seat, a second hose connector housing engaging the first hose connector housing and defining an exit passage, a generally flexible perforate membrane disk positioned between the first and second hose connector housings and pretensioned against the first valve seat to selectively sealingly separate the first and second hose connector housings, and a one-way relief valve fluidly connected with the exit passage and configured to permit venting of the exit passage upon overpressurization thereof.

In one aspect, a first portion of the membrane disk, such as a central portion thereof, is pretensioned against the first valve seat and a second portion of the membrane disk, such as an outer portion thereof, is pretensioned against a second valve seat. The membrane disk may be pretensioned against the first valve seat to selectively seal a first path between the first and second hose connector housings, thereby functioning as a check valve. The outer portion of the membrane disk may be pretensioned against the second valve seat to selectively seal a second path between the first and second hose connector housings, thereby functioning as a one-way relief valve.

In another aspect, at least one of the first and second hose connector housings defines an annular relief space and the one-way relief valve is positioned within the annular relief space.

In yet another aspect, the membrane disk includes a clamped portion secured between the first and second hose connector housings and the membrane disk further includes an outer portion projecting radially from the clamped portion within the annular relief space. The outer portion may be pretensioned against a second valve seat to selectively divide the annular relief space into an annular entry chamber and an annular exit chamber. The annular entry chamber may be fluidly connected to the exit passage by a connection channel and the annular exit chamber may be fluidly connected to the entry passage by a second connection channel.

In another aspect, the first and second hose connector housings may include opposing webs securing the clamped portion of the membrane disk therebteween. The opposing webs may define a circumferential wall of the annular relief space.

In yet another aspect, the membrane disk may define an opening for selectively fluidly connecting the entry passage and the exit passage when the membrane disk is unseated. For example, the opening may be surrounded by the valve seat. The first hose connector housing may define at least one connection channel extending from the entry passage to an entry space.

In another aspect, the check valve is configured for use with a respiratory tube having an inflatable cuff.

Referring now to preferred embodiments,FIG. 1shows a check valve1in a schematic cross-sectional view. The check valve generally includes a first hose connector housing2, a second hose connector housing4, and a perforate membrane disk6positioned between the housings2,4. The membrane disk6is preferably made of a flexible material such as silicone, silicone rubber, or rubber.

The membrane disk6is pretensioned against a first valve seat10monolithically formed in an entry space8of the first hose connector housing2. When the pressure in the entry passage7of the first hose connector housing2reaches a particular level, the membrane disk6will be lifted from the first valve seat10such that the entry space8is fluidly connected to an exit space12in the second hose connector housing4, as will be discussed further below. Thus, the membrane disk6and the first valve seat10cooperate to function as a check valve.

Additionally, the check valve1includes a relief valve16to prevent the pressure in the exit passage14from reaching an undesirably high pressure. For example, the relief valve16is fluidly connected with the exit passage14and is configured to permit venting of the exit passage14upon overpressurization thereof. InFIG. 1, the relief valve16is fluidly connected to the exit passage14via the exit space12and the relief valve16includes an outer portion of the membrane disk6, as will be discussed in further detail below.

The check valve1shown inFIG. 1may be particularly suited for medical applications. For example, referring toFIG. 2. the check valve1may be coupled with a respiratory tube101for inflating an inflatable cuff108of the respiratory tube101. Respiratory tubes101typically include a breathing tube104for delivering air to a patient's lungs, an inflatable cuff108inserted within a patient's trachea102to prevent back-flow of the air delivered to the patient's lungs, and a connection line110for inflating the inflatable cuff108. The breathing tube104includes a proximal end112for connection with an air supply and a distal end106for insertion within the patient's trachea102. inflatable cuffs108are typically inserted into the patient's trachea102in a deflated state and are then filled with air to form a generally air-tight seal with the trachea102inner walls, thereby preventing the air delivered to the patient's trachea102from flowing back towards the patient's mouth. A respiratory tube device is disclosed in U.S. patent application Ser. No. 11/633,271, now published as Publication No. 2007/0163599, entitled “APPARATUS FOR CONNECTING A RESPIRATORY DEVICE WITH A PATIENT,” naming Jan W. M. Mijers as an inventor and filed Dec. 4, 2006, the entire contents of which is herein incorporated by reference.

The check valve1shown inFIG. 1may be connected to respiratory tube101shown inFIG. 2by fluidly connecting the exit passage14of the second hose connector housing4to the connection line110of the inflatable cuff108. Then, the inflatable cuff108may be inflated by an air source connected to the entry passage7. For example, a 50 ml syringe may be connected to the entry passage7of the first hose connector housing4. After the inflatable cuff108is inflated to a desired pressure, the syringe is removed so the pressure at the entry passage7of the first hose connector housing2is the atmospheric pressure. Therefore, if the air pressure within the inflatable cuff108reaches an undesirably high level, for example due to movement of the patient or due to a change of air pressure within the patient's lungs, air from the inflatable cuff108is able to be vented from the exit passage14to the entry passage7and into the atmosphere via the relief valve16, as will be discussed further below.

The first and second hose connector housings2,4cooperate to define an annular relief space18positioned radially outwardly of the entry space8. More specifically, inFIG. 1, the annular relief space18is formed by corresponding, opposing annular recesses in the first and second hose connector housings2,4.

The outer portion of the membrane disk6includes an annular marginal strip22radially exterior of its clamping point20that projects into the annular relief space18such that the outer edge23of the membrane disk can move upwardly and downwardly in a cantilever-like fashion. A second annular valve seat24is located within the annular relief space18and projects in the direction of the first hose connector housing2, i.e. in the direction of the entry space8. The second valve seat24pretensions the marginal strip22of the membrane disk in the direction of the entry space8such that the section of the membrane disk6between the clamping point20and the second valve seat24divides the relief space18into an annular entry chamber26and an annular exit chamber28. The second valve seat24may be monolithically formed with the second hose connector housing4.

The annular entry chamber26is connected with the exit space12of the second hose connector housing4by one or more connection channels30and the annular exit chamber28is connected with the entry space8of the first hose connector housing2by one or more connection channels32.

The membrane disk6includes a clamped portion for securing the membrane disk6between the first and second hose connector housings2,4. For example, as shown inFIG. 1, the membrane disk6includes an annular protrusion34radially inwardly of the marginal strip22. The annular protrusion34may be monolithically formed with the membrane disk6by a suitable method, such as injection molding. The first hose connector housing2and the second hose connector housing4inFIG. 1are each provided with opposing annular webs36,38for securing the annular protrusion34. For example, the annular webs38,38each include an annular groove40and42for securing the annular protrusion34. The annular grooves40and42receive the annular protrusion34to clamp the membrane disk6between the two hose connector housings2,4, thereby pretensioning the center section of the membrane disk6against the first valve seat10.

As shown inFIG. 1, the annular webs36and38define the circumferential wall44of a cavity46that is divided Into the entry space8and the exit space12by the membrane disk6. Additionally, the annular webs36,38define the connection channels30,32. Furthermore, the annular webs36,38define the radial inner wall48of the relief space18.

As also shown inFIG. 1, the membrane disk6includes a central opening50which is selectively sealingly separated from the entry space8by the first valve seat10. The entry space8is fluidly connected with the entry passage7of the first hose connector housing2by one or more connection channels52. Therefore, incoming air is able to flow from the entry passage7to the entry space8by the connection channels52and the air pressure differential between the entry space8and the exit space12causes the membrane disk6to become unseated from the first valve seat10, thereby fluidly connecting the entry space8to the exit space12via the opening50.

The radial outer wall54defining the relief space18includes an upwardly projecting annular skirt56that engages a corresponding annular groove58of the second hose connector housing4. The annular skirt56and the annular groove58cooperate to form a connection between the two hose connector housings2,4. The annular skirt56and the annular groove58may also be fixedly connected by a suitable method, such as welding, ultrasonic welding, by use of medically approved adhesives (e.g. ultra-violet curing adhesives), or by a combination thereof. The housings may be comprised of polymeric materials that are generally medically accepted, e.g. polystyrenes, styrenic copolymers (A.B.S.) or polycarbonates.

During use of the check valve1, when the pressure differential between the exit space12and the entry space8reaches a particular level, air is able to be vented from the exit space12to the entry space8by airflow through the connection channels30,32and by downward movement of the marginal strip22. More specifically, the marginal strip22is able to be lifted from the second valve seat24such that air flows from the entry chamber26above the marginal strip22to the exit chamber28below the marginal strip22.

It is therefore intended that the foregoing detailed description be regarded as illustrative rather than limiting, and that it be understood that it is the following claims, including all equivalents, are intended to define the spirit and scope of this invention. More particularly, the apparatus and assembly described are merely an exemplary apparatus and assembly, and they are not intended to be limiting.