Patent Description:
Dialysis is a process of removing excess fluid and waste products from blood in individuals whose kidneys have lost the ability to perform these functions in a natural way, for instance due to chronic kidney disease. There are two main types of dialysis: haemodialysis and peritoneal dialysis. The haemodialysis procedure involves pumping the blood of the patient through a disposable dialyser filter on one side of a semi-permeable membrane and pumping clean dialysate fluid through the disposable dialyser filter on the other side of the semi-permeable membrane. This allows the toxins to move across the semi-permeable membrane into the dialysate fluid and be removed from the blood. The blood and dialysate are pumped to and from the dialyser filter along fluid lines.

The operator of a haemodialysis machine must ensure that the key components of the dialysis machine are disinfected, to avoid infecting the patient. More specifically, components which are in direct contact with fluids, for example those forming a dialysate circuit, must be disinfected throughout the duration of the treatment. The connectors and reusable clamps of the haemodialysis machine form part of the dialysate circuit. Typically, these components are disinfected with chemicals and hot water after every treatment.

<CIT> discloses an exemplary dialysate circuit. The dialysate circuit comprises a bicarbonate source that is connected to a purified water source. Purified water is mixed with bicarbonate in a bicarbonate container in a known manner to create a bicarbonate solution, or a dialysate fluid. Known haemodialysis machines utilise dialysate fluid to filter blood as explained above.

It is common for dialysis machines to use powdered sodium bicarbonate as a purifying agent. Typically, sodium bicarbonate is packaged and transported as a dry powder stored inside a dedicated container. These containers have approximately the same form factor and connector stems for attachment to a dialysis machine. These connector stems fit into reusable standard clamp connections on the dialysis machine, and therefore form part of the dialysate circuit.

It is known that standard connectors require frequent disinfection. This increases the cost of treatment, and the duration of preparation for each treatment.

It would be desirable to provide a new connector for the dialysis machine. <CIT> discloses medical push connectors and systems. The medical push connector has a body with lumen (extending between proximal and distal ends of the body) and ports. The medical push connector can be releasably coupled or disposed at a distal end of a syringe. The connector includes first and second release members which are configured to enable releasable coupling.

<CIT> discloses a fitting for releasably and sealingly connecting a conduit to a medical instrument. <CIT> discloses Systems and methods for controlling fluid movement and volumes of fluid between a subject and a controlled compliant flow path.

According to the first aspect of the present invention there is provided a disposable dialysate source container connector as set out in claim <NUM>.

Advantageously, the connector is adapted to permanently mate to the dialysate source container. As such, the connector and the container can be discarded together after use. This removes the need for disinfection of the connector, thus reducing the length and complexity of the dialysis procedure and increasing utilisation factor of the dialysis machine. The resilient nature of the flexible radial protrusions facilitates easier assembly of the connector and also connection of the connector to the container. The annular seal, the o-ring and the grip ring are easily installed into the collar and do not move out of position, as the protrusions keep them in their positions.

The at least two flexible radial protrusions may have a ramp angled toward the first port.

The first ring may include a plurality of circumferentially disposed radially inwardly extending teeth.

Advantageously, upon inserting of the container to the connector, the teeth are embedded into the stem of the container, thus providing an irreversible connection between the connector and the container.

The at least two flexible radial protrusions may comprise a plurality of circumferentially disposed flexible radial protrusions extending from the inner surface of the collar.

The fluid conduit may be formed of a first conduit and a second conduit in fluid communication with the first conduit. The second fluid conduit may be disposed substantially transversely with respect to the first conduit.

The second port may be adapted to receive a flexible tube.

Advantageously, the bend on the fluid conduit prevents kinking of the flexible tube. This ensures unobstructed flow of fluids across the connector.

The connector may be made from a polymeric material.

Advantageously, the connector is cheap to make, light, and given the disposable nature does not require additional disinfection after use.

According to the second aspect of the present invention there is provided a blood purification system as set out in claim <NUM>.

The stem may be received by the annular gap between the fluid conduit and the collar of the connector. The stem may also engage with the annular seal to establish a fluid-tight connection between the connector and the container.

The ramp may be adapted to centre the stem, the grip ring, the retaining ring, and the annular seal within the collar.

The stem engages with the grip ring to establish an irreversible connection between the connector and the container.

In use, the container and the connector may be disposable as a single assembly.

The connector <NUM> comprises a body <NUM>, a collar <NUM>, an annular seal <NUM>, a grip ring <NUM>, and a retaining ring <NUM>.

The body <NUM> defines a fluid conduit <NUM>. The fluid conduit <NUM> has a first port <NUM> and a second port <NUM> disposed at each end of the fluid conduit <NUM>.

The collar <NUM> surrounds the first port <NUM>. The collar <NUM> defines an inner surface <NUM> which has a stepped profile. The stepped profile provides a surface against which the annular seal <NUM>, the grip ring <NUM>, and the retaining ring <NUM> are seated.

The collar <NUM> further includes a series of circumferentially disposed windows <NUM> and a series of circumferentially disposed protrusions <NUM>. The protrusions <NUM> are aligned with the windows <NUM> such that there is one protrusion <NUM> for each window <NUM>. Each protrusions <NUM> further includes a ramp <NUM>. The ramp <NUM> is angled towards the first port <NUM>.

The annular seal <NUM>, the grip ring <NUM>, and the retaining ring <NUM> are each generally annular. The grip ring <NUM> includes a series of teeth <NUM> extending radially inwards and towards the first port <NUM>. The annular seal <NUM> may be an o-ring, although any suitable shape which fits onto the inner surface <NUM> is possible. The retaining ring <NUM> is disposed on top of the grip ring <NUM> so as to secure the grip ring <NUM> and the annular seal <NUM> to the inner surface <NUM> of the collar <NUM>. The retaining ring <NUM> is held in position by the protrusions <NUM>, as will be explained in more detail below.

A flexible tube <NUM> is received in the second port <NUM> of the fluid conduit <NUM>. The flexible tube <NUM> may be made of PVC. The flexible tube <NUM> may be solvent bonded to the second port <NUM>.

The fluid conduit <NUM> is formed of a first fluid conduit <NUM> and a second fluid conduit <NUM>. The first fluid conduit <NUM> extends substantially along a vertical axis A and the second fluid conduit <NUM> extends substantially along a horizontal axis B. Hence, the second fluid conduit <NUM> is disposed substantially transverse with respect to the first fluid conduit <NUM>.

As shown in <FIG>, the first fluid conduit <NUM> is arranged along a vertical axis A, and encircled by a tube <NUM>. The tube <NUM> is arranged within the collar <NUM> to define an annular gap <NUM> therebetween. The collar has a pair of shims 39a extending vertically away from the collar <NUM>. The shims 39a are disposed opposite to each other on a top surface <NUM> of the collar <NUM>, and disposed circumferentially along a portion of the top surface <NUM> of the collar <NUM>. A ridge <NUM> is disposed on an inside surface of the tube <NUM> and extends radially towards the vertical axis A. The ridge <NUM> may prevent a user from inserting a male connector, for instance a male luer connector, into the tube <NUM>.

Referring to <FIG>, the top surface <NUM> of the connector <NUM> is drafted, to facilitate easier removal of the connector <NUM> from a mould following injection moulding. The shims 39a are disposed on lowermost areas of the drafted top surface <NUM>. The shims 39a stabilise the container <NUM> about the vertical axis A when a fluid under variable pressure flows from the container <NUM> and through the connector <NUM>, as will be explained in more detail below.

In a preferred embodiment, shown in <FIG>, the stepped inner surface <NUM> includes a first inner surface 23a, a second inner surface 23b, a third inner surface 23c, and a fourth inner surface 23d. Each of said inner surfaces (23a to 23d) extend circumferentially around and along the vertical axis A. The annular gap <NUM> is defined between the tube <NUM> and the first inner surface 23a. The second inner surface 23b provides an engaging surface for the annular seal <NUM>. The third inner surface 23c provides an engaging surface for the grip ring <NUM>. The fourth inner surface 23d provides an engaging surface for the retaining ring <NUM>. The retaining ring <NUM> is held between the fourth inner surface 23d and the protrusions <NUM>. The inner surfaces are of varying diameter, such that the first inner surface 23a is the smallest in diameter, and the fourth inner surface is the largest in diameter.

Referring to <FIG>, the collar <NUM> also defines three seats - a first seat 25a, a second seat 25b, and a third seat 25c. Each said seat is disposed perpendicularly to each inner surface, such that each seat forms an annulus disposed circumferentially around the vertical axis A. Each said seat separates two neighbouring inner surfaces, such that the first seat 25a separates the first inner surface 23a and the second inner surface 23b, the second seat 25b separates the second inner surface 23b and the third inner surface 23c, and the third seat 25c separates the third inner surface 23c and the fourth inner surface 23d.

The third seat 25c includes a series of flats <NUM> disposed circumferentially around the vertical axis A and between the windows <NUM> of the collar <NUM>. In a preferred embodiment, the connector <NUM> comprises at least two flats <NUM>. Each flat <NUM> defines a surface for the retainer ring <NUM> to sit on. The flats <NUM> prevent the ring <NUM> from rocking side to side, causing leakage. A combination of flats <NUM> and shims 39a prevents the rocking of the connector <NUM>, thereby significantly reducing the risk of fluid leakage from the connector <NUM>.

The annular seal <NUM> engages the second inner surface 23b and is disposed on the first seat 25a. The grip ring <NUM> engages the third inner surface 23c and is disposed on the second seat 25b. The retaining ring <NUM> engages the fourth inner surface 23d and is disposed on the third seat 25c.

The connector <NUM> is assembled as follows:
First the annular seal <NUM> is inserted through the collar <NUM> and disposed on the first seat 25a, and such that the seal <NUM> engages the second inner surface 23b. Second, the grip ring <NUM> is inserted into the collar <NUM>, such that it engages the third inner surface 23c and the second seat 25b. Third, the retaining ring <NUM> is inserted through the collar <NUM> and disposed on the third seat 25c, and such that the retaining ring <NUM> engages the fourth inner surface 23d. The diameters of both the annular seal <NUM> and the grip ring <NUM> is less that the collar <NUM> and less that the space provided between radially opposing protrusions <NUM>, such that the annular seal <NUM> and the grip ring <NUM> fit easily between the protrusions <NUM>.

The diameter of the retaining ring <NUM> is larger than the space provided by the radially opposed protrusions <NUM>. Due to the presence of the windows <NUM>, the protrusions <NUM> are flexible and are able to resile in the radial direction. The protrusions <NUM> have ramps <NUM> which are angled towards the first port <NUM> of the connector <NUM>. Therefore, during the insertion of the retaining ring <NUM>, the ramps <NUM> are the first component which contacts the retaining ring. Advantageously, the ramps <NUM> facilitate easier insertion of the retaining ring <NUM> into the connector <NUM>.

The flexible nature of the protrusions <NUM> is utilised in order to place the retaining ring <NUM> in position. The retaining ring <NUM> is forcibly inserted past the protrusions <NUM>, which resile in the radial direction. Once the retaining ring <NUM> has passed the protrusions <NUM>, the protrusions elastically return to their initial position. The retaining ring <NUM> is thus held in place on top of the grip ring <NUM> and under the protrusions <NUM>. In this position, the retaining ring <NUM> is stacked upon the annular seal <NUM> and grip ring <NUM>, and holds the annular seal <NUM> and grip ring <NUM> securely in place.

<FIG> shows a schematic representation of two connectors <NUM> as part of a dialysate circuit <NUM> of a dialysis machine. The dialysate circuit <NUM> includes a disposable cartridge <NUM>, for example the dialysate mixing and pumping cassette of <CIT>, or the dialysate mixing and pumping cassette of <CIT>.

The disposable cartridge <NUM> is responsible for pumping and mixing dialysate and has a clean dialysate outlet port <NUM>, a spent dialysis inlet port <NUM>, a water inlet port <NUM>, a water outlet port <NUM> and a bicarbonate solution inlet port <NUM>. Ports <NUM>, <NUM> are fluidically connected to dialyser <NUM>. Dialyser <NUM> has a blood inlet port <NUM> for receiving blood from arterial blood line <NUM> and blood outlet port <NUM> for sending blood to venous blood line <NUM>.

Purified water is admitted into the cartridge <NUM> from a purified water supply <NUM> via the water inlet port <NUM>. The purified water passes through the cartridge <NUM> and exits the cartridge <NUM> at the water outlet port <NUM>. The bicarbonate container <NUM> has a purified water inlet port <NUM> and a bicarbonate solution outlet port <NUM>. Purified water is passed from the water outlet port <NUM> of the cartridge <NUM> to the purified water inlet port <NUM> of the bicarbonate container <NUM> via flexible tubing <NUM> and connector <NUM>. Similarly, bicarbonate solution is passed from the bicarbonate solution outlet port <NUM> of the bicarbonate container <NUM> via flexible tubing <NUM> and connector <NUM>. The bicarbonate solution enters the cartridge <NUM> via bicarbonate solution inlet port <NUM>. The flexible tubing <NUM> may be made from PVC. The flexible tubing <NUM> may be solvent bonded to the connectors <NUM>.

Therefore, the connector <NUM> is used to provide an irreversible fluid tight connection from a purified water supply (via the disposable cartridge <NUM>) to a container <NUM>, or to provide an irreversible fluid tight connection from the container <NUM> to the dialysis machine, or both.

The use of connector <NUM> at the purified water inlet port <NUM> of the bicarbonate container <NUM> and the use of the connector <NUM> at the bicarbonate solution outlet port <NUM> of the bicarbonate container <NUM> are similar, such that only the later shall be described in detail.

With reference to <FIG>, the blood purification system comprises the connector <NUM> as set forth above, and the container <NUM> for storing bicarbonate powder, or any other suitable source of dialysate.

The container <NUM> has a substantially cylindrical body <NUM>, and a stem <NUM> extending from at least one end of the container <NUM>. The body <NUM> defines an interior <NUM>, where the dialysate powder is stored. The stem <NUM> has a bicarbonate solution outlet port <NUM> disposed at the free end of the stem <NUM>. The stem <NUM> further includes a chamfered edge <NUM> on the wall of the stem <NUM> that faces away from the port <NUM>.

The stem <NUM> is received in the annular gap <NUM> of the connector <NUM>. The port <NUM> of the stem <NUM> partially receives the first fluid conduit <NUM> thus fluidly connecting the first fluid conduit <NUM> to the container <NUM>. The stem <NUM> receives the entirety of the port <NUM> of connector <NUM>.

When inserted into the connector <NUM>, the stem <NUM> of the container <NUM> engages the grip ring <NUM> and the annular seal <NUM>.

The annular seal <NUM> provides a fluid tight connection between the container <NUM> and the connector <NUM>. On the other hand, the grip ring <NUM> provides an irreversible connection between the container <NUM> and the connector <NUM>.

The annular seal <NUM> engages the second inner surface 23b and the first seat 25a of the collar <NUM>, as well as the wall of the stem <NUM> facing away from the port <NUM>. As such, the system can remain pressurized upon passing fluid from the interior <NUM> of the container <NUM> into the fluid conduit <NUM>, or vice versa.

Upon inserting the stem <NUM> into the annular gap <NUM> between the fluid conduit <NUM> and the collar <NUM>, the teeth <NUM> bend further towards the annular gap, thus exerting a reaction force on the wall of stem <NUM> facing away from the port <NUM>.

During the insertion of the container <NUM> into the connector <NUM>, or vice versa, the chamfered edge <NUM> is the first element of the container <NUM> engages the grip ring <NUM>.

In use, the operator of the dialysis machine can only insert the container <NUM> into the annular gap <NUM> in the direction in which the teeth <NUM> of the ring <NUM> are pointing. Once the teeth <NUM> of the grip ring <NUM> engage the stem <NUM>, the connector <NUM> firmly grips the container <NUM>, and both components become irreversibly connected.

The retaining ring <NUM> reacts the forces due to the spring back of the teeth <NUM> of the grip ring <NUM>, thus the retaining ring <NUM> is constrained axially by the protrusions <NUM>. This constraint further ensures that the container <NUM> cannot be removed from the connector <NUM>.

In use, upon completing the treatment, the container <NUM> and the connector <NUM> are disposed of as a single assembly.

Claim 1:
A disposable dialysate source container connector (<NUM>) comprising:
a body defining a fluid conduit (<NUM>), the fluid conduit (<NUM>) having a first port (<NUM>) at one end and a second port (<NUM>) at another end, the body having a collar (<NUM>) disposed around the first port (<NUM>), defining an annular gap (<NUM>) between the fluid conduit (<NUM>) and the collar (<NUM>), and having a stepped inner surface (<NUM>) and a radially inwardly extending seat (<NUM>), wherein the collar (<NUM>) comprises at least two flexible radial protrusions (<NUM>) extending from the inner surface (<NUM>);
an annular seal (<NUM>);
a grip ring (<NUM>); and
a retaining ring (<NUM>);
wherein the annular seal (<NUM>), the grip ring (<NUM>) and the retaining ring (<NUM>), are disposed around the fluid conduit (<NUM>) on the inner surface (<NUM>), and wherein the annular seal (<NUM>) engages the seat (<NUM>) of the collar (<NUM>), and wherein the retaining ring (<NUM>) is stacked on the grip ring (<NUM>) which, in turn, is stacked on the annular seal (<NUM>), and wherein the at least two radial protrusions (<NUM>) engage the retaining ring (<NUM>) to retain the grip ring (<NUM>) and the annular seal (<NUM>) within the body of the connector (<NUM>); wherein in use the connector (<NUM>) attaches to the container (<NUM>) via the stem (<NUM>) so as to provide an irreversible and fluid-tight connection between the connector (<NUM>) and the container (<NUM>).