Patent Description:
A dialysis machine filters a patient's blood of toxins by pumping the blood 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.

To connect the fluid lines to the connector ports of the dialyser filter, two types of connectors are used - one is a screw thread and the other is a push fit. The geometries of both of these types of connector ports are detailed in the standard ISO <NUM>-<NUM>.

Typically, dialysis machines use reusable versions of the push fit connectors while the screw fit connectors are part of the disposable blood tube sets. As the push fit connectors form part of the dialysate circuit, they require sterilization using hot water after each treatment and further chemical treatment on a regularly scheduled basis. As the push fit connectors are designed to be used many hundreds or thousands of times, these connectors are also designed to be robust, and are therefore expensive.

It is known to use a disposable cartridge to produce dialysate fluid and pump this through the dialyser filter. As a result, a disposable push fit connector is also required to fluidically connect the cartridge to the dialyser filter. Disposable push fit connectors are already available and are typically moulded as a single component from a flexible material which conforms around one of the connection ports on a dialyser filter. These connectors have the disadvantage of being very difficult to attach and remove and also may be prone to being pushed off by high pressures, especially after use over time. This invention relates to a new design of push fit dialyser connector which is inexpensive enough to be disposable but strong enough to be more reliable and convenient for a user. <CIT> discloses medical devices including vascular access kits and related methods. <CIT> discloses a system (<NUM>; <NUM>) for providing vascular access in a patient's body.

Aspects and embodiments of the invention provide a dialyser connector, a dialysate mixing and pumping cartridge comprising a dialyser connector, a method of assembling a dialyser connector and a method of connecting a dialyser connector to a dialyser filter connector port as claimed in the appended claims.

According to an aspect of the invention, there is provided a dialyser connector comprising a main body and a sliding clip, the main body has a tube end and a dialyser end, the main body defines a cavity, at least one aperture and a pair of ramps, and the sliding clip has a tube end and a dialyser end, the sliding clip defines a spine connecting the tube end and a dialyser end, the sliding clip has a pair of flexible wings extending in an arc from the spine and a pair of arms extending in an arc from the spine, the pair of arms have at least one projection extending radially inward, wherein the dialyser connector has a locked condition in which the at least one projection extends into the cavity of the main body and an unlocked conditions in which the at least one projection is withdrawn from the cavity of the main body, and wherein the at least one projection is biased to the locked condition by resilient abutment of pair of flexible wings on the pair of ramps.

The at least one projection may comprise a pair of projections and the at least one aperture may comprise a pair of apertures.

At least one arm of the pair of arms may have a hook configured to abut a shoulder of the main body to prevent detachment of the sliding clip from the main body when assembled.

The central portion may be bounded toward the tube end by a circumferential flange, preferably the central portion may be partially bounded toward the dialyser end by two arcuate flanges.

The main body may have a projection, preferably wherein the spine has a notch.

The projection may be aligned with the vertical plane and extends from an upper surface of the main body.

The dialyser connector may further comprise a seal, preferably wherein the seal comprises an O-ring seal. Alternatively, the seal may comprise an overmould on the main body.

The dialyser connector may be symmetrical about a centred vertical plane.

The dialyser connector may be single use. The dialyser connector may be plastic.

One of the pair of arms may have a hinged latch. The hinged latch may be connected to the arm by a living hinge. The hinged latch may terminate in a wedge shape and the other of the pair of arms may have a corresponding ledge.

According to another aspect of the invention, there is provided a dialysate mixing and pumping cartridge comprising a dialyser connector as hereinbefore defined.

According to yet another aspect of the invention, there is provided a method of assembling a dialyser connector as hereinbefore defined, the method comprising the steps of: inserting an O-ring seal axially into the main body <NUM> from the dialyser end; mounting the sliding clip over the main body; slotting the pair of arms over the central portion with the at least one projection dropping into the at least one aperture with a snap fit connection, wherein the arm comprises a hook which abuts a shoulder of the main body to prevent detachment of the sliding clip from the main body when assembled.

According to a further aspect of the invention, there is provided a method of connecting a dialyser connector to a dialyser filter connector port, the method comprising the steps of providing a dialyser connector as hereinbefore defined, depressing the spine of the sliding clip relative to the main body so as to withdraw the at least one projection from the recess of a dialyser filter connector port, connecting the dialyser connector to the dialyser filter connector port, releasing the spine of the sliding clip relative to the main body so that the dialyser connector automatically assumes a locked condition in which the at least one projection engages a recess of a dialyser filter connector port under the biasing action of the pair of flexible wings on the pair of ramps.

The method may further comprise the step of disconnecting the dialyser connector from the dialyser filter connector port by depressing the spine of the sliding clip relative to the main body so as to withdraw the at least one projection from the recess of a dialyser filter connector port, and withdrawing the dialyser connector from the dialyser filter connector port.

The dialyser connector <NUM> comprises a main body <NUM>, a sliding clip <NUM> and an O-ring seal <NUM>.

The dialyser connector <NUM> has a tube end <NUM> configured for connection to flexible dialysate tubing <NUM> and a dialyser end <NUM>, configured for connection to a dialyser filter connector port <NUM>, as will be described in more detail below. Looking end-on, in the orientation shown in all figures, the dialyser connector <NUM> is symmetrical about a vertical plane passing between the tube end <NUM> and the dialyser end <NUM>.

The main body <NUM> is a single piece. The main body <NUM> defines a cylindrical cavity. The main body <NUM> has a tube end <NUM> and a dialyser end <NUM>. Looking end-on, the main body <NUM> is symmetrical about a vertical plane passing between the tube end <NUM> and the dialyser end <NUM>.

The tube end <NUM> and the dialyser end <NUM> are separated by a central portion <NUM>. The tube end <NUM> terminates in a tube connector <NUM>. The dialyser end <NUM> includes a shoulder <NUM> on each side. The dialyser end <NUM> terminates in an annulus <NUM>. The annulus <NUM> is separated from the central portion <NUM> by two apertures <NUM>. The two apertures <NUM> being provided on either side of the vertical plane.

The central portion includes a ramp <NUM> on either side, increasing a wall thickness of the central portion <NUM>. The central portion <NUM> is bounded toward the tube end <NUM> by a circumferential flange <NUM>. The central portion <NUM> is partially bounded toward the dialyser end <NUM> by two arcuate flanges <NUM>.

A projection <NUM> extends from an upper surface of annulus <NUM>. The projection is aligned with the vertical plane.

The sliding clip <NUM> is a single piece. The sliding clip <NUM> has an arcuate form, having a tube end <NUM> and a dialyser end <NUM>. Looking end-on, the sliding clip <NUM> is symmetrical about a vertical plane passing between the tube end <NUM> and the dialyser end <NUM>.

The tube end <NUM> and the dialyser end <NUM> are connected by a spine <NUM> running along the top of the sliding clip <NUM>. The spine <NUM> has a depression <NUM>. The spine has a notch <NUM>, centrally aligned and toward the dialyser end <NUM>. The tube end <NUM> comprises a pair of flexible wings <NUM> which extend in approximately <NUM> degree arcs from the spine <NUM>, along either side of the sliding clip <NUM>. The dialyser end <NUM> comprises a pair of arms <NUM> which extend in approximately <NUM> degree arcs from the spine <NUM>, along either side of the sliding clip <NUM>. The pair of flexible wings <NUM> are separated from the pair of arms <NUM> by respective cut-outs <NUM>.

A dialyser end portion of an inside surface of each of the pair of arms <NUM> includes a cut-out <NUM> which defines a hook <NUM> adjacent the end of each arc. A tube end portion of the inside surface of each of the pair of arms <NUM> has a projection <NUM> adjacent the cut-outs <NUM>. The projections <NUM> extend radially inward, along a portion of each arc. The projections <NUM> have a chamfer <NUM> facing the dialyser end <NUM>.

The O-ring seal <NUM> is inserted axially into the main body <NUM> from the dialyser end <NUM>, and retained in an annular recess <NUM> of an inside surface of the main body <NUM>, adjacent the tube end <NUM>.

The dialyser connector <NUM> is assembled with the sliding clip <NUM> mounted over the main body <NUM>.

At the dialyser end <NUM>, the pair of arms <NUM> are slotted over the central portion <NUM>, with the projections <NUM> dropping into the respective apertures <NUM>. This is a snap fit connection, the pair of arms <NUM> must flex outwardly when contacting the central portion <NUM>, given that the gap G between the innermost points of the projections <NUM> is smaller than the distance D on the main body <NUM> between the apertures <NUM>. Furthermore, each hook <NUM> of the pair of arms <NUM> abuts the shoulder <NUM> of the main body <NUM> to prevent detachment of sliding clip <NUM> from the main body <NUM>. At the tube end <NUM>, the pair of flexible wings <NUM> contact the ramp <NUM> on either side. The projections <NUM> impinge radially inwards through the apertures <NUM>, and into the cavity of the main body, such that they are visible when viewing the dialyser connector <NUM> from the dialyser end <NUM>.

The projection <NUM> extends through the notch <NUM> so that the projection is visible on the spine <NUM> of the sliding clip <NUM>.

Once assembled, the dialyser connector <NUM> may be manipulated between a locked condition in which the projections <NUM> engage a circumferential recess <NUM> of a dialyser filter connector port <NUM> and an unlocked conditions in which the projections <NUM> are withdrawn from the circumferential recess <NUM> of a dialyser filter connector port <NUM>.

The contact of the ramps <NUM> on the pair of flexible wings <NUM> biases the dialyser connector <NUM> to the locked condition. Thus the projections <NUM> are biased to engage the circumferential recess <NUM> of the dialyser filter connector port <NUM>.

Finger pressure upon the depression <NUM> of the spine <NUM> of the sliding clip <NUM> overcomes the biasing force as the pair of flexible wings <NUM> flex progressively up the inclined plane described by each ramp <NUM>, allowing downward movement of the sliding clip <NUM> relative to the main body <NUM>. The downward movement withdraws the projections <NUM> from impinging radially inwards through the apertures <NUM>, and thus out of engagement with the circumferential recess <NUM> of a dialyser filter connector port <NUM>. This allows removal of the dialyser connector <NUM> from the dialyser filter connector port <NUM>.

Because of the resilient nature of the flexible wings <NUM>, the dialyser connector <NUM> returns to the locked condition when the finger pressure is removed as the flexible wings <NUM> slide down the inclined plane described by each ramp <NUM>, thus returning the flexible wings <NUM> to an un-flexed condition.

The projection <NUM> acts as an alignment feature to ensure that the dialyser connector <NUM> remains aligned vertically as it slides downwards. This also gives a visual indication to a user that the dialyser connector <NUM> has been fully depressed or that the dialyser connector <NUM> has fully sprung back to the locked condition.

Referring to <FIG>, the O-ring seal <NUM> retained in an annular recess <NUM> of an inside surface of the main body <NUM>, and abuts an outer end surface of the dialyser port <NUM>. This provides a fluid tight seal between the dialyser connector <NUM> and the dialyser <NUM>. The dialyser port <NUM> could be an inlet or and outlet of the dialyser <NUM>.

The chamfer <NUM> on the projections <NUM> forces the sliding clip <NUM> downwards as it is pushed onto a dialyser port <NUM>. This allows the connector <NUM> to be attached to a dialyser port <NUM> without pushing the sliding clip <NUM> down manually. The right angle on the rear of the projections <NUM> prevents the connector <NUM> from being removed without first pushing the sliding clip <NUM> down. Furthermore, the projection <NUM> maintains the sliding clip <NUM> straight as it slides down relative to the main body <NUM>.

The dialyser connector <NUM> or the sliding clip <NUM> may be colour-coded to aid differentiation of the inlet and outlet connectors.

In an alternate embodiment, the seal is provided as an overmould on the main body <NUM>. The overmould seal seals against the dialyser in the same manner as the O-ring seal <NUM>. <FIG> shows a schematic representation of the dialyser connector <NUM> in use with 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> and a spent dialysis inlet port <NUM>. These 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>. Dialyser <NUM> further has dialyser filter connector ports <NUM>, in this case identified by dialysate inlet port <NUM> and dialysate outlet port <NUM>. Two dialyser connectors <NUM> are used. One dialyser connector <NUM> fluidically connects clean dialysate outlet port <NUM> to the dialysate inlet port <NUM> using flexible dialysate tubing <NUM>. Another dialyser connector <NUM> fluidically connects spent dialysate inlet port <NUM> to the dialysate outlet port <NUM> using flexible dialysate tubing <NUM>. The flexible dialysate tubing <NUM> may be made from PVC. The flexible dialysate tubing <NUM> may be solvent bonded to the tube connector <NUM>. In one embodiment, an outer surface of the PVC dialysate tubing <NUM> is coated with a mix of butanone and cycolohexanone and pushed into the tube connector <NUM>. The solvent melts the two surfaces together, then evaporates to form a bond.

In an alternate embodiment, the tube end <NUM> of the dialyser connectors <NUM> terminate in a cartridge connector (not shown). The cartridge connector connects directly to the disposable cartridge <NUM>, without the need for flexible dialysate tubing <NUM>.

<FIG> show an alternate embodiment of a dialyser connector generally designated <NUM>. The dialyser connector <NUM> includes many of the features of dialyser connector <NUM> described above, only the main differences shall be described in detail.

Similar reference numbers are used to designate similar features as with respect to dialyser connector <NUM>.

In the dialyser connector <NUM>, one of the pair of arms <NUM> of the dialyser end <NUM> of the sliding clip <NUM> comprises a hinged latch <NUM>. The hinged latch <NUM> extends from an end <NUM> of one the pair of arms <NUM> by means of a living hinge <NUM>. The hinged latch <NUM> terminates in a wedge shape <NUM>. The wedge shape <NUM> includes a projection <NUM>. The other of the pair of arms <NUM> terminates in a corresponding ledge <NUM>. The ledge <NUM> has a corresponding recess <NUM>.

During use, the hinged latch <NUM> folds up and locks in place by means of the projection <NUM> engaging with recess <NUM>, as the wedge shape <NUM> hooks over ledge <NUM>.

The sliding clip <NUM> is still able to be moved relative to the main body <NUM>, as per the dialyser connector <NUM> (see <FIG>).

The hinged latch <NUM> maintains the dialyser connector <NUM> firmly attached to the dialyser filter connector port <NUM>. Furthermore, the hinged latch <NUM> prevents the pair of arms <NUM> from flexing outwards under excess pressure. The projection <NUM> and corresponding recess <NUM> provides an alignment feature which prevents the hinged latch <NUM> from axial movement relative to the ledge <NUM>.

The hinged latch <NUM> may be released from engagement with the other of the pair of arms <NUM> by squeezing the pair of arms <NUM> together whilst stretching the hinged latch <NUM> to disengage the wedge shape <NUM> from ledge <NUM>.

Claim 1:
A dialyser connector (<NUM>,<NUM>) comprising:
a main body (<NUM>) and
a sliding clip (<NUM>),
the main body (<NUM>) has a tube end (<NUM>) and a dialyser end (<NUM>),
the main body (<NUM>) defines a cavity, at least one aperture (<NUM>) and a pair of ramps (<NUM>), and
the sliding clip (<NUM>) has a tube end (<NUM>) and a dialyser end (<NUM>),
the sliding clip (<NUM>) defines a spine connecting the tube end (<NUM>) and a dialyser end (<NUM>),
the sliding clip (<NUM>) has a pair of flexible wings (<NUM>) extending in an arc from the spine and a pair of arms (<NUM>) extending in an arc from the spine,
the pair of arms (<NUM>) have at least one projection (<NUM>) extending radially inward,
wherein the dialyser connector (<NUM>,<NUM>) has a locked condition in which the at least one projection extends into the cavity of the main body (<NUM>) and an unlocked conditions in which the at least one projection (<NUM>) is withdrawn from the cavity of the main body (<NUM>), and
wherein the at least one projection (<NUM>) is biased to the locked condition by resilient abutment of pair of flexible wings (<NUM>) on the pair of ramps (<NUM>).