Patent Description:
Hemodialysis treatments require an extracorporeal blood circulation. The blood circuit comprises an out-tube intended to supply blood from the patient to the hemodialysis machine, where blood is passed through a filter in order to remove waste products. The blood circuit further comprises an in-tube intended to supply filtered blood from the hemodialysis machine back to the patient.

Most of the recent hemodialysis machines are designed to perform also the so called hemofiltration and/or hemodiafiltration treatments. Hemofiltration treatment implies the removal of some waste water from the blood and, accordingly, it needs also to compensate the removal by means of the addition of saline solution, i.e. the so called substitution liquid. Where such treatment is combined with a traditional hemodialysis, the so called hemodiafiltration treatment is obtained. In the following, for sake of simplicity, with the term "hemofiltration" reference will be made both to the actual hemofiltration and to the hemodiafiltration treatments.

Such recent hemodialysis machines further need a substitution line intended to supply the substitution liquid in the blood flow directed to the patient. According to some machines, for example the one disclosed in <CIT>, the substitution line is obtained from the water system (see <FIG>). In particular, water coming from the water system is subjected to an ultrafiltration treatment by the machine itself, then in the ultrafiltered water salts are dissolved which are needed for making it a physiological solution usable as a substitution liquid. Thus the machine comprises a port (shown in detail in <FIG>) intended to supply the substitution liquid.

The substitution line of the disposable tubing set needs to be connected to the substitution port of the machine by means of a disposable connector. A disposable connector according to the prior art is shown in <FIG> and <FIG>. Such prior art connector, although widely used and appreciated, is not defect-free. It comprises four different components: a main body, a fixing thread, an o-ring seal, and a slotted membrane. In addition, the prior art connector comprises at least one removable cap or, in the most complicated version shown in <FIG>, two removable caps. The main body and the fixing thread are usually obtained from polycarbonate or some other rigid material suitable for medical use. The o-ring seal and the slotted membrane are usually obtained from silicone or some other soft material suitable for medical use.

The assembly of the disposable connector of the known type requires that the membrane is inserted in its seat obtained along the duct of the main body, till it rests on the shoulder. Then also the fixing thread has to be inserted along the same duct, till it contacts the membrane. The main body and the fixing thread are then joined together by means of ultrasound welding, so as to hold the silicone membrane in place. The assembly of the known connector is then finished by slipping the o-ring seal along the main body to its seat and, in case, by putting on the two caps.

As can be easily appreciated by the skilled person, the prior art connector is quite complex and relatively expensive. The relatively high number of pieces, with respect to the overall dimensions of the connector, requires a time-consuming assembly. Moreover, the ultrasound welding step requires both dedicated equipments and qualified personnel.

<CIT> discloses a connector comprising a rigid main body and a soft element. Other similar connectors are disclosed in <CIT>; <CIT>, <CIT>; <CIT> and <CIT>.

The aim of the present invention is therefore to at least partially solve the drawbacks highlighted in relation to known connectors for hemofiltration treatments.

A task of the present invention is to provide a disposable connector having a simple structure, i.e. made of fewer components with respect to the known one.

Another task of the present invention is to reduce the production and assembly costs of the disposable connector.

The aim and the tasks indicated above are accomplished by a disposable connector according to claim <NUM>.

The characteristics and the further advantages of the invention shall become clear from the following description of some embodiments, given for indicating and not limiting purposes with reference to the attached drawings, in which:.

Referring to the enclosed figures, the reference <NUM> indicates a disposable connector suitable for engagement on the substitution port <NUM> of a hemofiltration machine <NUM>. The connector <NUM> comprises: a rigid main body <NUM> defining a duct <NUM>; and a soft element <NUM> fitted on an end of the main body <NUM>. In the connector <NUM> according to the invention, the soft element <NUM> comprises a membrane <NUM> occluding the duct <NUM> and performing a valve function; and a seal portion <NUM> radially expanding outward of the duct <NUM>.

In the attached figures, same references are used for elements which have same or similar functions, both in the connector according to the invention and in the one according to the prior art.

The main body <NUM> is preferably obtained from polycarbonate (PC), acrylonitrile-butadienestyrene (ABS), unplasticized polyvinyl chloride (uPVC) or some other rigid material suitable for medical use. The soft element <NUM> is preferably obtained from silicone, thermoplastic elastomer (TPE) or some other soft material suitable for medical use.

According to the embodiments shown in the attached <FIG>, <FIG>, <FIG> and <FIG>, the connector <NUM> according to the invention is, as a whole, L-shaped. Specifically, duct <NUM> defined by the main body <NUM> is L-shaped, having a main axis X and a secondary axis Y, see in particular <FIG>. Conversely, according to the embodiment shown in the attached <FIG>, the connector <NUM> according to the invention has a straight development. Specifically, duct <NUM> defined by the main body <NUM> has a straight development, having one axis X only. In the following description reference will be made principally to axis X. Consequently, except in case of explicit contrary indication, the term "axial" refers to the direction of a straight line parallel to axis X, the term "radial" refers to the direction of a half-line having its origin on axis X and perpendicular thereto, the term "circumferential" refers to the direction of a circumference having its centre on axis X and laying on a plane perpendicular thereto.

As can be noticed in <FIG>, the port <NUM> of the machine <NUM> comprises an inner cone <NUM> and a coaxial outer sleeve <NUM>. The inner cone <NUM> defines a supply channel for the substitution liquid, while the outer sleeve <NUM> defines a protected interspace <NUM> around the inner cone <NUM>. The outer sleeve <NUM> further defines a drain channel <NUM> which is used during the preparatory step for the hemofiltration treatment. Such step is schematically shown in <FIG> where the port <NUM> is closed by a proper plug. In such condition the substitution liquid coming from the machine <NUM> is forced to circulate between the outer wall of the inner cone <NUM> and the inner wall of the outer sleeve <NUM>, and then to flow out through the drain channel <NUM>. Such circulation allows an accurate washing of the port <NUM>, so as to assure hygiene of the connection.

According to some embodiments of the disposable connector <NUM>, the membrane <NUM> is suitable for alternatively assuming a closed configuration or an open configuration. In particular, membrane <NUM> preferably assumes the closed configuration in a spontaneous manner, or at rest, i.e. in absence of any force directly acting upon it. See in this regard <FIG> wherein connector <NUM> is shown isolated, disengaged from the machine <NUM>.

Conversely, membrane <NUM> assumes the open configuration after engagement of the connector <NUM> on the machine <NUM>, in particular because of the specific conformation of the port <NUM> on which connector <NUM> is engaged. See in this regard <FIG> wherein connector <NUM> is shown engaged with port <NUM>; it can be noticed that the inner cone <NUM> pushes the membrane <NUM>, forcing it to the open configuration. In such condition duct <NUM> of connector <NUM> becomes an extension of the supply channel defined by the inner cone <NUM>. Moreover, in the open configuration, the membrane <NUM> adheres on the outer wall of the inner cone <NUM>, thus sealing the supply channel from the interspace <NUM>. A successive disengagement of the connector <NUM> from the port <NUM>, removing all the forces acting on the membrane <NUM>, entails that the latter spontaneously assumes back its closed configuration, thus closing duct <NUM>.

According to some embodiments of the invention, e.g. the one shown in <FIG>, <FIG>, <FIG> and <FIG>, the membrane <NUM> comprises a simple diametrical slot <NUM>. According to other embodiments of the invention, e.g. the one shown in <FIG>, the membrane <NUM> comprises a Y-shaped slot <NUM>, i.e. a slot formed of three cuts extending radially from the center of the membrane and spaced by <NUM>° one from the other.

As disclosed above, the soft element <NUM> comprises also a seal portion <NUM>, intended to cooperate with the port <NUM> of the machine <NUM>. In particular, the seal portion <NUM> is intended to make contact with the inner wall of the outer sleeve <NUM> so as to seal the interspace <NUM> from the outer environment. Engagement between connector <NUM> and port <NUM> of the machine <NUM> entails a slight interference between the seal portion <NUM> and the inner wall of the outer sleeve <NUM>. As can be noticed in <FIG> and <FIG>, wherein the seal portion <NUM> is free from any contact, the seal portion <NUM> radially extends outward and has a substantially semicircular cross section. On the contrary in <FIG>, wherein the seal portion <NUM> is constricted by the inner wall of the outer sleeve <NUM>, the seal portion <NUM> has a smaller radial extension and a squashed cross section.

According to the embodiments shown in the attached figures, see in particular <FIG>, the main body <NUM> comprises an undercut <NUM> and an axial shoulder <NUM> which radially extends outward. The undercut <NUM> is placed near the end of the main body <NUM> upon which the soft element <NUM> is fitted. Complementarily, the soft element <NUM> comprises a radial step <NUM> which protrudes inward. When the soft element <NUM> is forcedly fitted on the end of the main body <NUM>, the axial end <NUM> of the soft element <NUM> contacts the shoulder <NUM> and the radial step <NUM> engages the undercut <NUM>. In such a manner a shape coupling is established between the soft element <NUM> and the main body <NUM>.

The shape coupling assures that the connector <NUM> remains firmly assembled during its use. According to some embodiments, such coupling is further strengthened by the specific shape of the soft element <NUM>, or by the finish of the contact surfaces, or by both of them.

In particular, the coupling can be strengthened by the reciprocal positions of the radial step <NUM> and of the seal portion <NUM> with respect to the axial end <NUM>. As can be noticed in <FIG>, the distance D between the radial step <NUM> and the axial end <NUM> is longer than or equal to the distance d between the seal portion <NUM> and the axial end <NUM>. When the connector <NUM> is engaged on the port <NUM>, the specific relationship between D and d allows to exploit the radial pressure exerted by the outer sleeve <NUM> on the seal portion <NUM> in order to prevent the radial step <NUM> from any possible disengagement from the undercut <NUM> due to its deformation.

The coupling between the main body <NUM> and the soft element <NUM> can also be strengthened by the finish of the respective surfaces which contact each other. In particular, a very smooth surface finish entails a strong adhesion between the two surfaces. Accordingly, the contact zone <NUM> of the main body <NUM> (see <FIG>) and the contact zone <NUM> of the soft element <NUM> (see <FIG>) have very smooth surfaces, i.e. polished or lapped surfaces. As the skilled person will appreciate, since both the main body <NUM> and the soft element <NUM> are made of plastic materials, polishing and/or lapping treatments are actually carried out on the respective areas of the moulds, rather than on each single plastic piece.

According to some embodiments, connector <NUM> further comprises one or two caps referenced to with <NUM> and <NUM> respectively. Such caps, which are suitable for plugging the ends of the duct <NUM>, are intended to be removed before use. <FIG> shows the connector <NUM> with both caps <NUM> and <NUM>. <FIG> shows the same connector <NUM> of <FIG> engaged on the port <NUM> and still having its cap <NUM> on. <FIG> shows a different embodiment of the connector <NUM> wherein only cap <NUM> is provided. Accordingly the other end of duct <NUM> is open and, in particular, is suitable for receiving a delivery tube to be glued therein.

Claim 1:
Connector (<NUM>) configured for engagement on the substitution port (<NUM>) of the hemofiltration machine (<NUM>) of claim <NUM> for carrying out a hemofiltration or a hemodiafiltration treatment of a patient's blood, wherein the connector (<NUM>) comprises:
- a rigid main body (<NUM>) defining a duct (<NUM>); and
- a soft element (<NUM>) fitted on an end of the main body (<NUM>), the soft element (<NUM>) comprising:
- a membrane (<NUM>) occluding the duct (<NUM>) and performing a valve function; and
- a seal portion (<NUM>) radially expanding outward of the duct (<NUM>)
wherein the membrane (<NUM>) is suitable for alternatively assuming a closed configuration or an open configuration, the connector being characterized in that the seal portion (<NUM>), when free from any contact, radially extends outward and has a substantially semicircular cross section.