Patent Description:
<CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT> and <CIT> relate to one-way valves for use in medicine.

International publication <CIT> relates to a check valve suitable for use with IV sets, providing an upstream filter for prevention of contamination from affecting the sealing of the check valve membrane. <FIG>, <FIG>, <FIG>, Fig.<NUM>, Fig.7A and Fig.8A of said international publication show that a flat membrane is employed in the check valve.

In general, fluid flow through the one-way valves in the current state of the art mainly occurs at flow paths between their respective flexible members and shells, and the flow is streamed through a substantially closed geometry, e.g. an annular space.

Geometrical details around such spaces are prone to cause dead volumes, purging of the fluids around which is difficult. Fluid flow around such dead zones inevitably occurs with lag and has unacceptably low linear velocity to allow effective cleaning of the wet surfaces of such valves.

This causes difficulty and inefficiency in washing/cleaning of such valves, and blood or drugs in liquid form can remain in such dead zones for unacceptably long times. Especially blood is known to be a fertile medium for rapid bacterial growth, and therefore dead zones are not wanted to be present in valves for medical use.

Therefore it is an intention to make improvements on flow paths inside one way intravenous needle free valve for medical use.

Primary object of the present invention is to overcome the abovementioned shortcomings of the prior art.

Another object of the present invention is to provide a one way intravenous needle free valve in which formation of dead volumes is minimized or eliminated.

A further object of the present invention is to provide a one way intravenous needle free valve with enhanced flow control.

Another object of the present invention is to provide a one way intravenous needle free valve without reflux.

The present invention proposes a one way intravenous needle free valve including a shell providing a fluid flow path along an axis between an inlet and an outlet; a flexible member placed between the inlet and the outlet and constrained throughout a circumferential edge thereof in a liquid-tight manner; an opening with a closed-geometry, in fluid communication with the inlet; the opening being aligned with a substantially impermeable central portion provided on the inlet side; wherein the member includes one or more holes around the central portion, providing a local fluid communication between the inlet side and the outlet side; and the member is shaped and sized to recline onto the opening such that the opening is substantially hermetically covered by the central portion when a fluid pressure at the outlet is equal to or greater than a fluid pressure at the inlet.

The drawings, whose brief explanation is herewith provided, are solely intended for providing a better understanding of the present invention and are as such not intended to define the scope of protection or the context in which said scope is to be interpreted in the absence of the description.

Referring now the drawings outlined before, the present invention proposes a one way intravenous needle free valve (<NUM>) (hereinafter abbreviated as "valve") including a shell (<NUM>) which can be formed from a substantially rigid (i.e. non-flexible) material, providing a fluid flow path along an axis (C) between an inlet (<NUM>) and an outlet (<NUM>).

The valve (<NUM>) according to the present invention further comprises a flexible member (<NUM>) (hereinafter abbreviated as "member") placed between the inlet (<NUM>) and the outlet (<NUM>). The member (<NUM>) is constrained inside the shell (<NUM>), substantially throughout a circumferential edge (<NUM>) (hereinafter abbreviated as "edge") thereof in a liquid-tight manner. Thus, any fluid flow over said edge (<NUM>) is substantially prevented by continuous liquid-tight contact surfaces around the edge. As a result of said contact, the edge (<NUM>) defines an inlet side (<NUM>) of the member (<NUM>) in fluid communication with the inlet (<NUM>), and an outlet side (<NUM>) of the member (<NUM>) opposite to said inlet side, in fluid communication with the outlet (<NUM>).

The valve (<NUM>) includes an opening (<NUM>) with a closed-geometry, said opening (<NUM>) being in fluid communication with the inlet (<NUM>). The opening (<NUM>) is aligned with a substantially impermeable central portion (<NUM>) provided on the inlet side (<NUM>).

The member (<NUM>) includes one or more holes (<NUM>) around the central portion (<NUM>), providing a local fluid communication between the inlet side (<NUM>) and the outlet side (<NUM>).

The member (<NUM>) is shaped and sized to recline onto the opening (<NUM>) such that the opening (<NUM>) is substantially hermetically covered by the central portion (<NUM>) at a "normal state" of the valve (<NUM>).

Here, the term "normal state" refers to a case where a fluid pressure at the inlet (<NUM>) does not exceed a fluid pressure at the outlet (<NUM>), thus the central portion (<NUM>) is not subjected to a net fluid pressure, therefore the member (<NUM>) is not pushed away from the opening (<NUM>) (or, in other words, towards the outlet (<NUM>)).

As a result, as long as the normal state is maintained, the opening (<NUM>) is kept covered by the central portion (<NUM>), such that any fluid communication between the opening (<NUM>) and the outlet side (<NUM>) is substantially prevented. Thus in the normal state, any occurrence fluid leakage from the outlet (<NUM>) to the inlet (<NUM>) is likewise prevented.

With the above disclosed features of the valve (<NUM>) according to the present invention, the following behavior of the valve (<NUM>) is achieved:.

With the valve according to the present invention, fluid flow in the direction (emphasized with a bold arrow in <FIG>) towards the outlet (<NUM>), is only allowed in the case where the fluid pressure at the inlet (<NUM>) (thus at the opening (<NUM>)) is higher than the pressure at the outlet (<NUM>) (thus at the outlet side (<NUM>)).

<FIG> is a detail (D) taken from the <FIG>, showing a normal state of an exemplary valve (<NUM>) according to the present invention. Here, an exemplary way to ensure that the central portion (<NUM>) abuts/reclines against the opening (<NUM>) such that fluid communication between the opening (<NUM>) and the outlet side (<NUM>) is substantially prevented.

<FIG> also shows the detail (D) from the <FIG>, showing an activated state of the same exemplary valve (<NUM>). Here, the central portion (<NUM>) is pushed away from the opening (<NUM>) by a net pressure force exerted by a fluid onto the central portion (<NUM>), which resulted in a reversible deformation of the member (<NUM>). Thus, fluid communication between the opening (<NUM>) and the outlet side (<NUM>) through the holes (<NUM>) is reversibly established.

In <FIG>, directions in which a fluid flow is possible (i.e. any flow direction) are symbolized with bold white arrows; and directiopns in which any fluid flow is prevented are symbolized with white arrows each being scored out with a dark line.

In a preferred embodiment as depicted in the <FIG>, <FIG>; the edge (<NUM>) can be sized and shaped to, in the normal state, prevent the member (<NUM>) from spreading in radial directions with regard to the axis (C), and to maintain the inlet side (<NUM>) substantially convex, such that the central portion (<NUM>) reclines against the opening (<NUM>) and thereby exerts an increased amount of mechanical pressure against the opening (<NUM>). This can be arranged by provision of an increased thickness to the member throughout its edge (<NUM>).

In other words, the member (<NUM>) can be arranged in the form of a membrane which has a substantially convex inlet side (<NUM>) for more effectively reclining against the opening (<NUM>) in the normal state. In this embodiment, the pressure exerted by the member (<NUM>) onto the opening (<NUM>) in the normal state is inherently higher when compared to a element (<NUM>) with a substantially flat inlet side (<NUM>). This embodiment thus provides an enhanced sealing of the opening (<NUM>) at the normal state. An inlet side perspective view of a member (<NUM>) according to such embodiment is shown in <FIG>. The member (<NUM>) exemplified in the <FIG> is provided with a plurality of holes (<NUM>) around the central portion (<NUM>). Yet, even though the member (<NUM>) would be provided with a single hole between the central portion (<NUM>) and the edge (<NUM>), such member (<NUM>) would still function as described above.

The member (<NUM>) being provided with a plurality of holes (<NUM>) substantially uniformly distributed around the central portion (<NUM>) is preferable, since the flexion of such member at transitions between the normal and active states, has an enhanced symmetry around the axis (C). Thus, the fluid flowing through the holes (<NUM>) causes a uniform drag force distribution thereto, providing an enhanced service life to the valve (<NUM>).

Preferably, a member (<NUM>) can be provided with a substantially convex inlet side (<NUM>), and further preferably, such member is further provided with a substantially concave outlet side (<NUM>); thus providing of a substantially uniform thickness around the central portion (<NUM>) and around the through hole(s) (<NUM>), thereby having an enhanced flexibility for reversible transitions between the normal state and the activated state of the valve (<NUM>).

As also exemplified in <FIG>, the shape and size of a section of the opening (<NUM>) can be arranged to remain within a projection of the central portion (<NUM>). Said section can be substantially perpendicular to a flow direction from the inlet (<NUM>) to the outlet (<NUM>), and said projection can be substantially parallel to said flow direction. In such embodiment, the hole(s) (<NUM>) inherently remain outside said projection, by being positioned around the central portion (<NUM>) (Le. between the central portion (<NUM>) and the edge (<NUM>).

In a further embodiment, the edge (<NUM>) of the member (<NUM>) can be constrained at the inlet side (<NUM>) by a support (<NUM>) (which is preferably formed from a substantially rigid/inflexible material), and by a further surface provided in the valve (<NUM>) circumferentially supporting the edge (<NUM>) outlet side (<NUM>). This feature ensures that the member (<NUM>) is better secured in place in case of where the pressure at the outlet (<NUM>) exceeds the fluid pressure at the inlet (<NUM>). The <FIG>, <FIG> visually exemplify such embodiment.

The member (<NUM>) can be provided with a lip (<NUM>) extended adapted by its shape and size to circumferentially surround a projection of the opening (<NUM>) substantially parallel to the axis (C). This embodiment enables exertion of an increased pressure around the opening (<NUM>) at the normal state, enhancing the sealing thereof.

The inlet (<NUM>) of the valve (<NUM>) according to the present invention can be provided with a swabbable connector (<NUM>). Swabbable connectors are widely used in the medical technology. Such swabbable connector (<NUM>) can be a luer connector, e.g. a male luer connector. Thus, the present invention further provides a reflux-resistant highly compact one-way valve (<NUM>) with a luer connector. Said compactness provides a decreased total size and weight to the valve (<NUM>), which in use enhances the comfort for a patient, in particular for pediatric use. Furthermore, the compactness has a favorable impact on production costs.

The one-way valve (<NUM>) according to the above mentioned preferred embodiment being also swabbable allows an enhanced minimization of a catheter occlusion effect prior to use. Thus a safe and effective anti-microbial barrier can be established and thereby catheter-related bloodstream infections (CRBSI) are effectively avoided.

One or more of the (substantially) rigid materials mentioned in the present description can comprise a thermoset resin.

The member (<NUM>) can be substantially formed from an organosilicon polymer. Polydimethyl siloxane (PDMS) can be considered highly suitable for being employed as a material to form the member (<NUM>) since it is highly compatible with bodily fluids.

Claim 1:
A one way intravenous needle free valve (<NUM>) including a shell (<NUM>) providing a fluid flow path along an axis (C) between an inlet (<NUM>) and an outlet (<NUM>); a flexible member (<NUM>) placed between the inlet (<NUM>) and the outlet (<NUM>) and constrained throughout a circumferential edge (<NUM>) thereof in a liquid-tight manner; an opening (<NUM>) with a closed-geometry, in fluid communication with the inlet (<NUM>); the opening (<NUM>) being aligned with a substantially impermeable central portion (<NUM>) provided on the inlet side (<NUM>); the member (<NUM>) includes one or more holes (<NUM>) around the central portion (<NUM>), providing a local fluid communication between the inlet side (<NUM>) and the outlet side (<NUM>); and the member (<NUM>) is shaped and sized to recline onto the opening (<NUM>) such that the opening (<NUM>) is substantially hermetically covered by the central portion (<NUM>) when a fluid pressure at the outlet (<NUM>) is equal to or greater than a fluid pressure at the inlet (<NUM>); the member (<NUM>) has an increased thickness around the edge (<NUM>),
characterised in that
the edge (<NUM>) has a size and shape to provide the member (<NUM>) with a substantially convex inlet side (<NUM>) and a substantially concave outlet side (<NUM>).