U.S. patent application number 12/733592 was filed with the patent office on 2011-12-15 for device and method for treating a medical fluid and medical cassette.
This patent application is currently assigned to Fresenius Medical Care Deutschland GmbH. Invention is credited to Gotz GUNTHER, Jurgen HACKER, Markus KOHLER, Martin LAUER, Ralf MULLER, Hans-Peter SCHNEIDER, Tobias WEBER, Manfred WEIS.
Application Number | 20110303597 12/733592 |
Document ID | / |
Family ID | 40130857 |
Filed Date | 2011-12-15 |
United States Patent
Application |
20110303597 |
Kind Code |
A2 |
GUNTHER; Gotz ; et
al. |
December 15, 2011 |
DEVICE AND METHOD FOR TREATING A MEDICAL FLUID AND MEDICAL
CASSETTE
Abstract
An apparatus for treating a medical liquid is provided which
includes a treatment machine having a coupling surface, with a
cassette made of a hard part having liquid-conducting passages
which are covered by a flexible film being able to be coupled to
the coupling surface of the treatment machine. A corresponding
medical cassette is also provided. An air-free coupling of the
flexible film of the cassette to the treatment machine is ensured
in that air can be sucked out areally along a plane between the
flexible film and the coupling surface during the coupling process
and/or with a coupled cassette. A method for coupling the cassette
and a method for checking the leaktightness of the cassette via the
vacuum control of the air suction is also provided.
Inventors: |
GUNTHER; Gotz; (Bad Homburg,
DE) ; HACKER; Jurgen; (Neu-Anspach, DE) ;
KOHLER; Markus; (Oberursel, DE) ; LAUER; Martin;
(St. Wendel, DE) ; MULLER; Ralf; (Oberursel,
DE) ; SCHNEIDER; Hans-Peter; (Neu-Anspach, DE)
; WEBER; Tobias; (St. Wendel, DE) ; WEIS;
Manfred; (St. Wendel, DE) |
Assignee: |
Fresenius Medical Care Deutschland
GmbH
Else-Kroener-Strasse 1
Bad Homburg
DE ASEA + 49 (0) 6172 609-0 !(0)6172 - 609 2105
info.ip@fmc-ag.com
61352
|
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20100200486 A1 |
August 12, 2010 |
|
|
Family ID: |
40130857 |
Appl. No.: |
12/733592 |
Filed: |
May 16, 2008 |
PCT Filed: |
May 16, 2008 |
PCT NO: |
PCT/EP2008/003978 |
371 Date: |
March 10, 2010 |
Current U.S.
Class: |
210/188; 29/428;
73/1.58 |
Current CPC
Class: |
Y10T 29/49826 20150115;
A61M 2205/122 20130101; A61M 1/14 20130101; A61M 1/1601 20140204;
A61M 1/28 20130101; A61M 1/16 20130101; A61M 1/34 20130101 |
Class at
Publication: |
210/188; 029/428;
073/001.58 |
International
Class: |
B01D 19/00 20060101
B01D019/00; G01L 27/00 20060101 G01L027/00; B23P 11/00 20060101
B23P011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 10, 2007 |
DE |
10 2007 042 964.0 |
Claims
1-60. (canceled)
61. An apparatus for treating a medical liquid which includes a
treatment machine having a coupling surface and a flexible mat
arranged on the coupling surface, with a cassette made of a hard
part having liquid-conducting passages which are covered by a
flexible film being able to be coupled to the coupling surface of
the treatment machine via the flexible mat, characterized in that
the flexible mat comprises an air-permeable material and is
configured such that air is sucked out in a region of the flexible
mat without interruptions during the coupling process and/or with a
coupled cassette, and indeed along the plane of the flexible mat
and/or through the flexible mat.
62. An apparatus for treating a medical liquid which includes a
treatment machine having a coupling surface and a flexible mat
arranged on the coupling surface, with a cassette made of a hard
part having liquid-conducting passages which are covered by a
flexible film being able to be coupled to the coupling surface of
the treatment machine via the flexible mat, characterized in that
the surface of the flexible mat facing the flexible film has a
structuring through which air can be sucked out along the
structuring of the flexible mat during the coupling process and/or
with a coupled cassette.
63. An apparatus in accordance with claim 62, wherein the
structuring has a net structure and/or a meander-like and/or linear
structure.
64. An apparatus in accordance with claim 62, wherein the
structuring is made anisotropoic and/or inhomogeneous.
65. An apparatus in accordance with either claim 62, wherein the
structuring extends along the liquid-conducting passages.
66. An apparatus in accordance with claim 65, wherein the
structuring converges in one or more regions outside the
liquid-conducting passages which form suction points.
67. An apparatus in accordance with claim 62, wherein the
structuring extends substantially perpendicular to the passage web
edge on the transition from the region with liquid-conducting
passages to the region outside the liquid-conducting passages.
68. An apparatus in accordance with claim 65, wherein the
structuring has a spacing from the passage web edges in the regions
in which it does not traverse the passage web edges.
69. An apparatus in accordance with claim 65, wherein the
structuring is made such that there is no direct connection between
regions of the film with different liquid-conducting passages.
70. An apparatus in accordance with claim 62, wherein the cassette
is pressed with the coupling surface in the coupled state, with the
film being pressed in a fluid-tight manner with the
liquid-conducting passages of the hard part of the cassette, but
with the structuring along its plane allowing air transport.
71. An apparatus for treating a medical liquid which includes a
treatment machine having a coupling surface and a flexible mat, in
particular a silicone mat, arranged on the coupling surface, with a
cassette made of a hard part having liquid-conducting passages
which are covered by a flexible film being able to be coupled to
the coupling surface of the treatment machine via the flexible mat,
characterized in that air can be sucked out along a plane between
the flexible film and the surface of the flexible mat facing the
flexible film during the coupling procedure and/or with a coupled
cassette.
72. An apparatus in accordance with claim 61 comprising at least
one suction device.
73. An apparatus in accordance with claim 72, wherein the
air-conducting layer is in communication with a vacuum device at
one or more points outside the region of the liquid-conducting
passages.
74. An apparatus in accordance with claim 61, wherein the suction
takes place via at least one valve arranged in the coupling surface
of the treatment machine.
75. An apparatus in accordance with claim 61, wherein the suction
takes place via one or more suction openings arranged in the hard
part of the cassette.
76. An apparatus in accordance with claim 61, comprising an optical
sensor for the recognition of leaks, in particular by scattered
light wetting detection.
77. An apparatus in accordance with claim 61, comprising a control
which carries out an automatic suction of the air.
78. An apparatus in accordance with claim 77, wherein the control
carries out an automatic check of the leaktightness of the medical
cassette.
79. An apparatus in accordance with claim 61, comprising a medical
cassette in accordance with one of the following claims.
80. A medical cassette made of a hard part having liquid-conducting
passages which are covered by a flexible film, with the cassette
being able to be coupled to the coupling surface of the treatment
machine, the medical cassette comprising at least one suction
opening arranged in the hard part of the cassette.
81. A medical cassette in accordance with claim 80, wherein the
hard part has containment webs which connect the passage rim
sealing webs and form areas sealing pressed closed.
82. A medical cassette in accordance with claim 80, wherein the
suction opening is arranged outside the region of the
liquid-conducting passages.
83. A medical cassette in accordance with claim 80, wherein the
flexible film is welded to the hard part of the cassette around the
suction opening.
84. A medical cassette in accordance with claim 83, wherein the
annular weld seam has a structuring around the suction opening.
85. A medical cassette in accordance with claim 83, wherein the
region of the weld seam is lowered with respect to the pressing
plane of the cassette.
86. A medical cassette in accordance with claim 80, wherein a
hydrophobic filter is arranged at the suction opening.
87. A method for coupling a cassette made of a hard part having
liquid-conducting passages which are covered by a flexible film to
the coupling surface of a treatment machine for treating a medical
fluid comprising the steps: coupling the medical cassette to the
coupling surface of the treatment machine via a flexible mat
arranged on the coupling surface; suction of air between the
flexible film and the flexible mat during the coupling process
and/or with a coupled cassette, characterized in that the suction
takes place in regions of the flexible mat without interruptions,
and indeed along the plane of the flexible mat and/or through the
flexible mat, for which purpose the mat comprises an air-permeable
material.
88. A method for coupling a cassette made of a hard part having
liquid-conducting passages which are covered by a flexible film to
the coupling surface of a treatment machine for treating a medical
fluid comprising the steps: coupling the medical cassette to the
coupling surface of the treatment machine; suction of air between
the flexible film and the coupling surface of the treatment machine
during the coupling process and/or with a coupled cassette,
characterized in that the suction takes place along a structuring
of the surface of the flexible film and/or along a structuring of a
surface of a flexible mat facing the flexible film via which the
cassette is coupled to the coupling surface.
89. A method for coupling a cassette made of a hard part having
liquid-conducting passages which are covered by a flexible film to
the coupling surface of a treatment machine for treating a medical
fluid comprising the steps: coupling the medical cassette to the
coupling surface of the treatment machine via a flexible mat
arranged on the coupling surface; suction of air between the
flexible film and the flexible mat during the coupling process
and/or with a coupled cassette, characterized in that the suction
takes place along the plane between the flexible film and the
surface of the flexible mat facing the flexible film.
90. A method in accordance with claim 87, comprising a medical
cassette and/or an apparatus for treating a medical liquid in
accordance with one of the claims.
91. A method for checking the leaktightness of a medical cassette
made of a hard part having liquid-conducting passages which are
covered by a flexible film, in particular before the filling of the
medical cassette, comprising the steps: coupling the medical
cassette to a coupling surface of a treatment machine; suction of
air between the flexible film and the coupling surface of the
treatment machine, in particular areal suction during the coupling
process and/or with a coupled cassette; checking the leaktightness
of the medical cassette with reference to the created vacuum,
wherein the check of the leaktightness takes place during and/or
after the coupling of the cassette.
92. A method in accordance with claim 91, comprising a medical
cassette and/or an apparatus for treating a medical liquid in
accordance with one of the preceding claims.
Description
[0001] This is a national stage of PCT/EP08/003,978 filed May 16,
2008 and published in German, which has a priority of German no.
102007 042 964.0 filed Sep. 10, 2007, hereby incorporated by
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an apparatus for treating a
medical liquid which includes a treatment machine having a coupling
surface, with a cassette made of a hard part having
liquid-conducting passages which are covered by a flexible film
being able to be coupled to the coupling surface of the treatment
machine. The present invention further relates to a medical
cassette made of a hard part having liquid-conducting passages
which are covered by a flexible film, with the cassette being able
to be coupled to the coupling surface of the treatment machine. The
present invention further relates to an apparatus for treating a
medical liquid which includes a treatment machine having a coupling
surface, with a cassette made of a hard part having
liquid-conducting passages which are covered by a flexible film.
The present invention further relates to a method for coupling a
cassette made of a hard part having liquid-conducting passages
which are covered by a flexible film to the coupling surface of a
treatment machine for the treatment of a medical liquid as well as
to a method for checking the leaktightness of such a medical
cassette.
[0004] 2. Description of the Related Art
[0005] The treatment machine can be a blood treatment machine such
as is used in hemodialysis or in peritoneal dialysis. In such a
use, the medical cassette includes the blood-conducting or dialysis
liquid-conducting passages and is in communication with actuators
and sensors of the treatment machine via the coupling surface. The
medical cassette can thus be configured as a cost-effective
disposable part, whereas the actuators for the control of the
liquid flow through the cassette and the sensors are integrated
into the treatment machine for the level detection or for the
pressure measurement.
[0006] Such medical cassettes configured as disposable articles
comprise in this connection a thin-walled three-dimensional hard
plastic part having a planar peripheral contact edge and various
recesses (chambers, webs and passages). Medical liquids such as
dialysate or blood can now be conducted in the chambers and
passages formed by these three-dimensional structures of the hard
plastic part. The contact plane of the cassette is closed in a
liquid tight manner by a flexible film, advantageously a polymer
film which is peripherally connected, in particular welded and/or
adhesively bonded, to the contact edge of the hard part. The
medical cassette is pressed onto the coupling surface of the
treatment machine in use with the flexible film so that actuators
and sensors of the treatment machine lie on the polymer film. In
addition, the flexible film is pressed together with the webs of
the cassette by this pressing and thus provides a fluid tight
separation of the liquid-conducting passages in the hard part by
the webs and the flexible film.
[0007] The coupling surface of the treatment machine accordingly
usually has actuators, sensors and pressing force transmission
surfaces. The actuators and sensors of the blood treatment machine
are arranged in this context in the coupled state of the cassette
opposite the liquid-conducting passages of the cassette. The
actuators can hereby form valves by the pressing down of the film
in that the flexible film is pressed into regions of the
liquid-conducting passages and closes them. The sensors e.g.
measure the pressure or temperature of the liquid located in the
liquid-conducting passages. The pressing force transmission
surfaces press the flexible film against sealing webs of the hard
part which surround the liquid-conducting passages to seal them
with respect to one another and toward the rest of the cassette. In
this connection, the coupling surface is usually formed by a planar
surface of a support member which is made e.g. from metal, with
receivers for the sensors and the actuators being provided in said
surface, and by the sensors inserted into these receivers in planar
fashion.
[0008] A flexible mat, made e.g. of silicone or another elastomeric
material, is usually arranged on the coupling surface of the
treatment machine. This has the advantage that the sensor surfaces
are protected against environmental influences and the machine
surface is moreover liquid tight and thus ideally hygienically
cleanable. The flexible mat in this context represents a part of
the treatment machine to which the cassette is coupled as a
disposable part. The operation of the actuators is ensured by the
flexibility of the mat. In addition, the flexible film can be
pressed well to the coupling surface via the flexible mat, which
permits a good contact with the actuators, sensors and pressing
force transmission surfaces. The treatment machine can, however,
also be operated without a flexible mat so that the flexible film
lies directly on the coupling surface and the sensors and actuators
couple directly to the film.
[0009] There is, however, the difficulty with known systems in the
coupling of sensors to the film surface of achieving a good
coupling to obtain correct measured values. In particular air which
is trapped in the transmission path between the flexible film and
the sensor surface on the insertion of the cassette produces a
falsification of the measured results. This applies to pressure
sensors (in particular on the measurement of pressures which are
less than the environmental pressure), but also in level detection
and likewise to actuators such as valves. Unwanted air inclusions
between the outer surface of the flexible film and the mat surface
of the flexible mat lying thereon or, if no mat is used, of the
coupling surface of the treatment machine lying thereon should
therefore be eliminated on the coupling. This usually takes place
by air suction. In this context, however, the fluid contacting of
this space is complicated. There is in particular the problem that
a self-sealing of the film takes place by an application of the
film onto the mat or onto the coupling surface so that air islands
remain.
[0010] It is therefore known from DE 101 57 924 C 1 and DE 102 24
750 A 1 to realize the air transport by means of integrated mat
passages, predetermined in a defined manner, on the rear side of
the machine mat at the machine side. The air line from the surface
of the flexible film through the mat to the air passages arranged
on the machine side takes place locally through uninterrupted slots
in the region of the mat passages. The air transport however,
hereby only takes place at precisely defined points of the flexible
film of the cassette at which the air is sucked off through the
slots in the mat to the mat passages arranged on the machine side.
These mat passages therefore have to be located in the region of
the liquid-conducting passages of the cassette to ensure a good
suction there, which can lead to safety problems. Such a machine
mat having integrated mat passages and slots is moreover
cost-intensive in manufacture and complex and/or costly in
cleaning. The sensor surface is thus also no longer ideally
protected from environmental influences and hermetically sealed by
the mat so that hygienic problems also result. There is moreover
the need to further improve the reliability of the air suction
since the inclusion of air islands can still occur due to the only
local suction through the slots.
SUMMARY OF THE INVENTION
[0011] It is therefore the object of the present invention to
achieve a cost-effective, reliable and hygienic air suction.
[0012] This object is solved in accordance with the invention by an
apparatus for treating a medical liquid in accordance with claim 1.
It includes a treatment machine having a coupling surface, with a
cassette made of a hard part and having liquid-conducting passages
which are covered by a flexible film being able to be coupled to
the coupling surface of the treatment machine. In accordance with
the invention, in this connection, in the coupled state of the
cassette, a layer of an air-permeable porous material is arranged
between the flexible film and the coupling surface, at least in
partial regions, and air can be sucked out areally through said
layer during the coupling process and/or with a coupled cassette.
In accordance with the invention, air is no longer only selectively
sucked out at some points through the slots in the flexible mat so
that air islands may remain, as in the prior art, but is rather
sucked out areally through the layer of an air-permeable porous
material. A full-area suction of the air out of the region between
the flexible film and the coupling surface is thereby possible,
with air inclusions, which can never be precluded with only local
suction, being reliably prevented. In addition, the poorly
cleanable design of the flexible mat having mat passages can be
dispensed with and a flexible mat can be used substantially without
openings or no mat at all can be used.
[0013] It is possible in this context in accordance with the
invention that air can already be sucked out particularly
advantageously during the coupling process, in particular shortly
before the end of the coupling process. The contact pressure is
increased up to a maximum value in this connection on the coupling
of the cassette. The suction can already be begun in this context
as soon as the cassette contacts the coupling surface, but before
the cassette is pressed on with a maximum pressing force. A vacuum
can already be sucked out during this short phase. The porous
material or the structuring is in particular compressed still less
strongly in this phase and thus conducts air better. The suction of
the air can, however, also take place with a completely coupled
cassette.
[0014] The air can advantageously be sucked out through the layer
of an air-permeable porous material along the plane of the layer in
this connection. An air removal along the coupling plane is thereby
made possible, whereas simultaneously the actuators and sensors can
have an effect perpendicular to the coupling plane. It is
sufficient in this connection to have fluid contact to the space
between the film and the coupling surface at one or more suction
points and to connect the space to a suction apparatus, with the
air being sucked out areally from there along the coupling plane.
If a mat is provided, the flexible mat which otherwise has no
perforations can have openings at one or fewer points for fluid
contacting of the air-permeable porous layer.
[0015] Due to the layer made of an air-permeable, in particular
porous material, the vacuum for suction can act in the whole region
of the layer made of an air-permeable porous material, which makes
possible a full area, reliable suction. The material of the layer
is advantageously air-permeable both along the main plane of the
layer and also transversely to the main plane of the layer. The air
transport can hereby in particular also take place in the material
layer along its main plane, whereby the air between the surface of
the flexible film and the coupling surface is reliably sucked
out.
[0016] The layer of an air-permeable porous material is
advantageously arranged directly on the flexible film in the
coupled state of the cassette. A direction suction of the air from
the surface of the flexible film thereby results so that a reliable
coupling is made possible.
[0017] Further advantageously, the layer made of an air-permeable
porous material comprises a nonwoven. Such a nonwoven permits the
air transport described above, with it providing a uniform contact
between the coupling surface and the film and thus between the
sensors and actuators and the film, but simultaneously ensures the
areal suction in the plane between the flexible film and the
coupling surface or the flexible mat.
[0018] Further advantageously, the layer of an air-permeable
material is arranged over the whole area of the flexible film. A
cost-effective and simple possibility thus results to permit the
air suction over a full surface of the layer made of an
air-permeable material. It is, however, also possible for specific
applications only to provide such a layer of an air-permeable
material in part regions.
[0019] Further advantageously, the cassette is pressed with the
coupling surface in the coupled state, with the pressure
transmitted over the layer made of an air-permeable material
orthogonally to its plane during the coupling process and/or with a
coupled cassette pressing the film in a fluid tight fashion with
the liquid-conducting passages of the hard part of the cassette,
but with the layer made of an air-permeable material remaining
air-permeable along its plane. The layer made of an air-permeable
porous material can thus transmit the pressure required for the
sealing of the liquid-conducting passages by the interaction
between the webs of the hard part and the film which is pressed
onto the webs. At the same time, however, it remains gas-permeable
along its plane and thus provides an areal suction of the air
between the film and the coupling surface.
[0020] Further advantageously, the treatment machine has a flexible
mat, in particular a silicone mat, arranged on the coupling surface
and the cassette can be coupled to the coupling surface of the
treatment machine via the flexible mat.
[0021] In an advantageous embodiment, the treatment machine has a
flexible mat arranged on the coupling surface, with the cassette
being able to be coupled to the coupling surface of the treatment
machine via the flexible mat and a layer of an air-permeable
material being arranged between the flexible film and the flexible
mat in the coupled state of the cassette. The flexible mat can
hereby seal the coupling surface in a fluid tight manner and thus
provide an arrangement which is particularly simple to clean and is
hygienic, while the suction takes place via the air-permeable layer
arranged between the flexible mat and the flexible film. Silicone
or another suitable elastomer can be used as the material for the
flexible mat in this context. In this connection, a porous material
layer such as a nonwoven in turn proffers itself as an
air-permeable layer.
[0022] In the present invention, it is, however, also possible due
to the areal suction of the air along the coupling plane to
dispense with the flexible mat between the flexible film of the
cassette and the coupling surface of the treatment machine and only
to provide a layer of an air-permeable porous material such as a
nonwoven so that the flexible film of the medical cassette lies
directly on the coupling surface of the treatment machine via the
layer made of an air-permeable material without a mat therebetween
and the air suction takes place directly between the coupling
surface and the flexible film.
[0023] The present invention further includes an apparatus for
treating a medical liquid which includes a treatment machine having
a coupling surface and a flexible mat arranged on the coupling
surface, with a cassette made from a hard part having
liquid-conducting passages, which are covered by a flexible film,
being able to be coupled to the coupling surface of the treatment
machine via the flexible mat, with the flexible mat comprising an
air-permeable material and being configured such that air is sucked
out in a region of the flexible mat without openings during the
coupling process and/or with a coupled cassette, and indeed along
the plane of the flexible mat and/or through the flexible mat. By
the use of a permeable mat material, it is thus possible to
dispense with an additional layer made of an air permeable material
since the areal suction takes place via the flexible mat itself.
The supply of the vacuum can then take place via corresponding
passages in the coupling surface of the treatment machine. Since
thin silicone layers have a certain permeability for air, the
flexible mat can be formed of silicone and can be made very thin in
the regions in which air should be sucked out so that air can be
sucked out directly through the mat by application of a
correspondingly high vacuum. It is thus possible to dispense with
slots through the mat which make cleaning more difficult. The
coupling surface is moreover further sealed in a liquid tight
manner.
[0024] Alternatively or additionally to the layer described above
of an air-permeable porous material or to the flexible mat of an
air-permeable material, however, the surface of the film or the
surface of the flexible mat facing the film can have a structuring
via which air can be sucked out.
[0025] The present invention therefore further includes an
apparatus for treating a medical liquid which includes a treatment
machine having a coupling surface, with a cassette made of a hard
part having liquid-conducting passages which are covered by a
flexible film being able to be coupled to the coupling surface of
the treatment machine. In this connection, in accordance with the
invention, the surface of the flexible film has a structuring
through which air can be sucked out along the structuring of the
film during the coupling process and/or with a coupled cassette. A
secure suction of the air out of the region between the film and
the coupling surface or mat is thus also possible along the
coupling plane in that the air is sucked out through the passages
formed by the structuring of the film surface. The structuring thus
likewise permits an areal suction of the air and thus prevents the
formation of air islands, with it being provided at least in the
regions where an air-free coupling is required. The structuring in
the surface of the film is advantageously small enough in this
context so that no fluctuations, or only minimal fluctuations,
occur in the pressing force between the flexible film and the webs
of the hard part, but is large enough so that the passages arising
through the structuring are not completely closed by the pressure
between the coupling surface or mat and the film, but remain
air-conducting.
[0026] The structuring can take place by stamping of the film
surface in this connection. Alternatively, a structuring can also
be introduced directly on the extrusion of the film.
[0027] It is furthermore possible to apply a structuring to the
side of the flexible material facing the film. The present
invention therefore further includes an apparatus for treating a
medical liquid which includes a treatment machine having a coupling
surface and a flexible mat, in particular a silicone mat arranged
on the coupling surface, with a cassette made of a hard part having
liquid-conducting passages which are covered by a flexible film
being able to be coupled to the coupling surface of the treatment
machine via the flexible mat. In this connection, in accordance
with the invention, the surface of the flexible mat facing the
flexible film has a structuring through which air can be sucked out
along the structuring of the flexible mat during the coupling
process and/or with a coupled cassette. The suction through the
structuring of the surface of the flexible mat takes place in
precisely the same way as the suction through the structuring of
the flexible film such as was described above.
[0028] The structuring of the film, however, has the decisive
advantage with respect to a structuring of the surface of the mat
facing the film that the surface of the mat facing the film can be
made smooth and is thus easy to clean. The cassette is, in
contrast, anyway a disposable part so that it does not have to be
cleaned after use, but is disposed of.
[0029] Advantageous embodiments of the structuring which can be
used both for the structuring of the flexible film and for the
structuring of the mat surface will be described in the
following:
[0030] The structuring advantageously has a net structure and/or a
meander-like and/or a linear structure. The air can be sucked out
simply and reliably areally through a net structure, in particular
advantageously a honeycomb structure. A direct suction in specific
regions can, in contrast be achieved by a meander-like
structure.
[0031] Further advantageously, the structuring is made anisotropic
and/or inhomogeneous. It is thus possible to realize an anisotropic
suction by the selection of the suitable structure in that e.g. the
passages are made larger from left to right than from top to
bottom. The structure on the surface can also be made
inhomogeneous. It is e.g. hereby possible to realize a uniform
suction of the air in the surface, even if the space between the
film and the mat is only in fluid contact with the suction
apparatus at one point.
[0032] The aspect ratio of the channels which arise is important
for the achievable suction power with such a structuring. The width
of the passages is advantageously less than their depth in this
context. The passages are not closed by such narrow, deep passages
on the pressing of film and mat so that the suction remains
possible. The shallower the passages, the larger the risk of
sealing by a partial contact of the film on the mat would be. It
the passages become too wide, the risk moreover increases that the
pressing on the smooth rear side of the film with the webs of the
hard part becomes too inhomogeneous and that leaks occur on this
side between the liquid-conducting passages.
[0033] In a further embodiment, the structuring of the film surface
or of the mat surface can extend along the liquid-conducting
passages. Only a lower volume thereby has to be evacuated so that
the time required for the suction or for an initial leaktightness
test is reduced. In addition, the air is only sucked out where
there is actually a need for an air-free connection between the
film and the flexible mat. Such an air-free coupling is, in
contrast, not necessary in the regions without liquid-conducting
passages. The structuring can therefore advantageously extend along
the liquid-conducting passages in meander-like and/or linear
form.
[0034] In this context, the structuring, however, advantageously
converges in one or more regions outside the liquid-conducting
passages which form suction points. A simple connection, e.g. with
a suction device, can thus take place in these regions outside the
liquid-conducting passages, whereas the structuring extending from
the suction point into the regions of the liquid-conducting
passages provides a reliable suction of the air out of these
regions.
[0035] The structuring advantageously extends substantially
perpendicular to the passage web edge on the transition from the
region with liquid-conducting passages to the region outside the
liquid-conducting passages. A uniform pressing of the film with the
passage web edges is hereby ensured without the structuring losing
its air-conducting function due to the pressing.
[0036] The structuring advantageously has a spacing from the
passage web edges in the regions in which it does not traverse the
passage web edges. The structuring is thus only capable of draining
in the liquid-wetted film areas required from a technical process
aspect. No air suction is necessary in contrast in the other
regions due to the high contact pressure between the film and the
hard part. The structuring is furthermore advantageously made such
that there is no direct connection between regions of the film with
different liquid-conducting passages. This has the advantage on a
rupture of the film that the liquid cannot spread over the whole
cassette along the structuring. Ruptures in a region without
liquid-conducting passages thus in particular also remain without
consequences. Even on a rupture of the film in a region of the
liquid-conducting passages the liquid is only sucked to the suction
point along the structuring, whereas a leak beyond the passage web
edges between the liquid-conducting passages is prevented.
[0037] However, a good and reliable pressing and air suction can
also be achieved on the use of a honeycomb structure which
naturally does not extend along the liquid-conducting passages and
with which the structuring is not always perpendicular on the
passage web edges. The simple and cost-effective manufacture is the
advantage of such a design.
[0038] The cassette in the method in accordance with the invention
is advantageously pressed with the coupling surface in the coupled
state, with the film being pressed in a fluid-tight manner with the
liquid-conducting passages of the hard part of the cassette, but
with the structuring along its plane allowing air transport.
[0039] The present invention further includes an apparatus for
treating a medical liquid which includes a treatment machine having
a coupling surface and a flexible mat, in particular a silicone mat
arranged on the coupling surface, with a cassette made of a hard
part having liquid-conducting passages which are covered by a
flexible film being able to be coupled to the coupling surface of
the treatment machine via the flexible mat. In accordance with the
invention, air can be sucked out along a plane between the flexible
film and the surface of the flexible mat facing the flexible film
during the coupling procedure and/or with a coupled cassette.
Equipping the flexible mat with the complex and/or expensive mat
passages and slots which are difficult to clean can hereby be
dispensed with. The air can rather be sucked out reliably and
simply between the mat surface and the flexible film. The suction
advantageously takes place via a layer of an air-permeable material
arranged at least in part regions or via a structuring of the
flexible film or of the mat surface. The advantages already
described above hereby result.
[0040] In accordance with the invention, air is thus no longer only
sucked out selectively through the slots in the flexible material
as in the prior art, but rather areally along the plane between the
film and the mat. It is hereby sufficient to have fluid contact to
the space between the film and the coupling surface at one or more
points and to connect the space to a suction apparatus, with the
air being sucked out areally from there along the coupling plane
between the film and the mat. The cost-intensive design of the
flexible mat with mat passages can thus be dispensed with. In
addition, a secure air-free coupling is ensured between the film
and the mat without the mat having to have slots so that a
liquid-tight and thus ideally hygienically cleanable machine
surface again becomes possible.
[0041] The suction of the air advantageously takes place via a
structure which is arranged in the region between the flexible film
and the flexible mat. An air conduction along the coupling plane is
thus made possible, whereas simultaneously the actuators and
sensors can have an effect perpendicular to the coupling plane. It
is in particular advantageously a case of an areal structure such
as the layer already named above made of an air-permeable material
or a structuring of the surface of the film or of the mat. A
full-area suction of the air out of this region is thereby
possible, with air inclusions, which can never be precluded with
only local suction, being reliably prevented.
[0042] Further advantageously, the apparatus in accordance with the
invention has at least one suction device. A vacuum can be made
available via this suction device, said vacuum being connected to
the region between the flexible film and the flexible mat or the
coupling surface and thus making the suction possible. It can be of
advantage in this context to implement the suction device in a
multiple fashion to improve the test capability of the suction
device.
[0043] Further advantageously, with the apparatus in accordance
with the invention, the air conducting layer is in fluid connection
with the suction device at one or more points outside the region of
the liquid-conducting passages independently of via which structure
the areal suction is realized. Since the suction takes place along
the coupling plane, it is no longer necessary in the present
invention to make a fluid connection with a vacuum apparatus
available directly in the region of the liquid-conducting
passages.
[0044] Further advantageously, in the apparatus in accordance with
the invention, the suction takes place via at least one valve
arranged in the coupling surface of the treatment machine. Said
valve is opened e.g. by pressing the cassette onto the coupling
surface of the treatment machine by means of a plunger and then
automatically sucks the air out of the air-conducting layer.
[0045] Alternatively, the suction can also take place through the
cassette. In this connection, a suction opening with a hydrophobic
membrane can be provided on the cassette. The suction therefore
advantageously takes place via one or more suction openings which
are arranged in the hard part of the cassette and which are
advantageously provided with a hydrophobic membrane. A simple fluid
contacting of the air-conducting layer is hereby possible.
[0046] Further advantageously, the apparatus in accordance with the
invention has an optical sensor for the recognition of leaks, in
particular by scattered light wetting detection. A simplified
contactless leak detection hereby results, in particular in
conjunction with a structuring of the film surface which varies its
reflection properties by discharge of liquid, which can be detected
by the optical sensor. Further advantageously, the apparatus in
accordance with the invention has a control which carries out an
automatic suction of the air. In this context, the control controls
the suction device and thus automatically provides an air-free
coupling of the medical cassette.
[0047] Further advantageously, the control carries out an automatic
check of the leaktightness of the medical cassette. This can be
carried out, as will be described further below, by a check of the
vacuum on the air suction.
[0048] Further advantageously, a medical cassette, which will be
shown in the following, is used in the apparatus in accordance with
the invention such as have already been described.
[0049] The medical cassette of the present invention in this
context includes a hard part having liquid-conducting passages
which are covered by a flexible film, with the cassette being able
to be coupled to a coupling surface of a treatment machine. In this
connection, in accordance with the invention, a structure is
arranged on the flexible film through which air can be sucked out
along the plane of the film surface during the coupling process
and/or with a coupled cassette. As already shown in detail with
respect to the apparatus for treating a medical liquid, it is
hereby possible to ensure a secure and reliable suction of the air
between the flexible film and the mat or the coupling surface of
the treatment machine. It is of particular advantage in this
context for the structure to form a component of the medical
cassette since this is a disposable part and therefore does not
have to be cleaned after use. The structure for the air suction
thus also does not have to satisfy any special conditions with
respect to cleanability.
[0050] A layer of air-permeable material, in particular porous
material, through which air can be sucked out areally along the
plane of the material layer in the coupled state of the cassette is
advantageously arranged on the flexible film at least in part
regions. The advantages of such an arrangement have already been
shown above with respect to the apparatus. The layer of an
air-permeable material, in particular a porous material, which is
arranged on the flexible film allows a reliable and uniform areal
suction of the air.
[0051] The layer of an air-permeable material is advantageously
arranged over the whole area of the flexible film. An inexpensive
and simple arrangement can thus be realized in which air can be
sucked out over the whole area between the flexible film and the
coupling surface of the treatment machine.
[0052] The layer of an air-permeable material is advantageously
welded to the cassette in a peripheral marginal region. The layer
of an air-permeable material thereby forms a unit with the cassette
and is securely held thereon. Further advantageously, the welding
of the layer of an air-permeable material takes place in a single
workstep together with the welding of the film with the hard part.
A cost-effective production can thus be realized.
[0053] Further advantageously, the weld forms a gas-tight barrier
along the plane of the material layer. It is hereby ensured by the
welding that air is only sucked out along the plane of the material
layer in the region in which the cassette is pressed with the
treatment machine. Otherwise air could be sucked out of side
regions and thus prevent a venting of the region between the
flexible film and the treatment machine. The fact can be utilized
in this context that on the welding of the layer of an
air-permeable material onto the film, the structure of the
advantageously porous material layer is modified such that a
gas-tight barrier is created. Sealing is therefore effected with
the flexible mat or the coupling surface at this point against a
material layer made air-impermeable. The layer of an air-permeable
material is advantageously welded to the hard part of the cassette.
For this purpose, the layer of an air-permeable material
advantageously comprises a material which can be welded to the
plastic from which the hard part of the cassette is produced.
[0054] Alternatively or additionally, the hard part of the cassette
can have a peripheral marginal region into which the structure, in
particular the layer of an air-permeable material, does not extend
so that this marginal region forms a sealing web on pressing. This
sealing web formed by the marginal region without structure
therefore ensures that the space between the film and the mat or
the coupling surface of the treatment machine can be reliably
vented. For this purpose, the layer of an air-permeable material or
a structuring can in particular be dispensed with in the marginal
region of the cassette.
[0055] Further advantageously, the flexible film is welded to the
hard part of the cassette in the peripheral marginal region. This
peripheral marginal region can thus be used for the welding to the
flexible film as in the prior art and can moreover serve as a
sealing web for the structure.
[0056] Further advantageously, in the present invention the layer
of an air-permeable material is connected, in particular adhesively
bonded and/or spot welded and/or pasted and/or laminated and/or
tacked to the film. A reliable grip of the layer of an
air-permeable material on the flexible material is hereby ensured,
e.g. even if the layer is not welded to the hard part in the
marginal region.
[0057] Further advantageously, with the medical cassette of the
present invention, the pressure transmitted during the coupling
process and/or with a coupled cassette via the structure, in
particular via the layer of an air-permeable material, orthogonally
to its plane presses the film with the liquid-conducting passages
of the hard part of the cassette in a fluid-tight manner. The
structure, in particular the layer of an air-permeable material, in
contrast remains gas-permeable along its plane. A reliable pressing
of the film and the hard part is thus possible in which no leaks
occur between the liquid-conducting passages, with nevertheless,
however, a reliable air suction via the areal structure remaining
possible. This is achieved by a corresponding configuration of the
material layer, e.g. of a nonwoven, or by the corresponding
configuration of the structuring of the surface of the flexible
film. Further advantageously, the layer made of an air-permeable
material comprises a non-woven. Such a nonwoven is ideally suited
for the uniform transmission of pressure and for the suction along
its plane.
[0058] In a further embodiment, the surface of the flexible film of
the medical cassette of the present invention can advantageously
have a structuring through which air can be sucked out along the
plane of the film in the coupled state of the cassette. It can
hereby be achieved in a simple manner that the air can be reliably
removed from the region between the film and the mat or between the
film and the coupling surface of the treatment machine without air
inclusions or air islands being formed. The arrangement of the
structuring on the surface of the film is of particular advantage
in this connection since the cassette is anyway disposed of after
use and thus does not have to be cleaned.
[0059] As already shown with respect to the apparatus for treating
a medical liquid, the structuring advantageously has a net
structure and/or a meander-like structure and/or a linear
structure. Further advantageously, the structuring is made
anisotropic and/or inhomogeneous. It is equally further of
advantage for the width of the passages formed by the structuring
to be less than the depth of these passages since they thereby do
not close on the pressing with the treatment machine and
nevertheless permit a uniform pressing of the smooth rear of the
film with the webs of the hard part.
[0060] In a further advantageous embodiment, the structuring
extends along the liquid-conducting passages, with use in
particular being made of a meander-like and/or a linear structure.
The volume which has to be evacuated can hereby be reduced. Further
advantageously, the structuring converges in one or more regions
outside the liquid-conducting passages which form suction points. A
simple suction can hereby take place in this region, whereas an
air-free coupling is ensured in this region along the
liquid-conducting passages via the structuring.
[0061] The structuring advantageously extends substantially
perpendicular to the passage web edge on the transition from the
region with liquid-conducting passages to the region outside the
liquid-conducting passages. A uniform pressing of the film with the
passage web edge is hereby ensured with a simultaneously good air
suction. The structuring advantageously has a spacing from the
passage web edges in the regions in which it does not traverse the
passage web edges. It can hereby be prevented that the liquid
spreads over the whole cassette along the structuring in the event
of a rupture. A better pressing of the film with the passage web
edges is moreover achieved.
[0062] The structuring is furthermore advantageously made such that
there is no direct connection between regions of the film with
different liquid-conducting passages.
[0063] This has the advantage on a rupture of the film that the
liquid cannot spread over the whole cassette along the structuring.
Ruptures in a region without liquid-conducting passages thus in
particular also remain without consequences. Even on a rupture of
the film in a region of the liquid-conducting passages the liquid
is only sucked to the suction point along the structuring, whereas
a leak beyond the passage web edges between the liquid-conducting
passages is prevented. Further advantageously, the hard part of the
medical cassette in accordance with the invention has containment
webs which connect the passage rim sealing webs and form closed
areas in a press-tight manner. The suction point is advantageously
disposed in such an area closed in a press-tight manner such that
on a film rupture the leak liquid only reaches this area and no
direct contact is possible between the individual liquid-conducting
regions.
[0064] Further advantageously, the medical cassette in accordance
with the invention has at least one suction opening arranged at the
hard part of the cassette. The space between the film and the mat
or the coupling surface can have a fluid contact for suction via
this suction opening. The flexible mat can hereby be made
throughgoing and thus ideally cleanable on the machine side.
[0065] The suction opening is advantageously arranged outside the
region of the liquid-conducting passages in this context. Security
is hereby increased since a failure of the weld only results in a
contamination of the suction device or of the hydrophobic membrane
arranged in the suction passage on a simultaneous rupture of the
film at a passage point or on a simultaneous failure of a sealing
web.
[0066] The flexible film is advantageously welded to the hard part
of the cassette around the suction opening.
[0067] In this context, the annular weld seam around the suction
opening advantageously has a structuring so as not to impair the
air suction by the weld seam. This is in particular important with
a structuring of the film surface and can e.g. be achieved via a
corresponding structure of the welding stamp.
[0068] Alternatively or additionally, the region of the weld seam
can also be lowered with respect to the pressing plane of the
cassette. An impairment of the air suction by the weld seam can
also be prevented by this. This is in particular also of particular
advantage on the use of a layer of air-permeable material.
[0069] Further advantageously, a hydrophobic filter is arranged at
the suction opening. In this context, the suction opening or the
suction openings are advantageously closed by one or more
hydrophobic filters in a liquid-tight manner. Hydrophobic filters
are liquid-tight and simultaneously gas-permeable.
[0070] The present invention further includes methods for coupling
a cassette to a treatment machine which permit a reliable air-free
coupling.
[0071] The present invention in this context includes a method for
coupling a cassette made of a hard part having liquid-conducting
passages which are covered by a flexible film to the coupling
surface of a treatment machine for treating a medical fluid
comprising the steps: coupling of the medical cassette to the
coupling surface of the treatment machine and suction of air
between the flexible film and the coupling surface of the treatment
machine during the coupling process and/or with a coupled cassette,
with the suction taking place areally via a layer of an
air-permeable porous material arranged at least in part regions
between the flexible film and the coupling layer. The steps of
coupling and of suction can be carried out either sequentially in
this process or at least partly simultaneously in that the suction
is started while the coupling process is still ongoing.
[0072] Alternatively, the suction can also take place along a
structuring of the surface of the flexible film and/or along a
structuring of a surface of a flexible mat facing the flexible film
via which the cassette is coupled to the coupling surface. The
advantages already shown with respect to the apparatus, in
particular a reliable suction of the air from the region between
the flexible film and the coupling surface of the treatment
machine, hereby result.
[0073] The invention furthermore includes a method for coupling a
cassette made of a hard part having liquid-conducting passages
which are covered by a flexible film to the coupling surface of a
treatment machine for treating a medical fluid comprising the
steps: coupling of the medical cassette to the coupling surface of
the treatment machine via a flexible mat arranged on the coupling
surface, suction of air between the flexible film and the flexible
mat during the coupling process and/or with a coupled cassette,
with the suction taking place in regions of the flexible mat
without interruptions, and indeed along the plane of the flexible
mat and/or through the flexible mat, for which purpose the mat
comprises an air-permeable material.
[0074] The present invention furthermore includes a method for
coupling a cassette made of a hard part having liquid-conducting
passages which are covered by a flexible film to the coupling
surface of a treatment machine for treating a medical fluid
comprising the steps: coupling of the medical cassette to the
coupling surface of the treatment machine via a flexible mat, in
particular a silicone mat, arranged on the coupling surface and
suction of air between the flexible film and the flexible mat
during the coupling process and/or with a coupled cassette, with
the suction taking place along the plane between the flexible film
and the surface of the flexible mat facing the flexible film. The
advantages already described above also hereby result. The flexible
material can in particular be made inexpensively and easy to clean
in this context.
[0075] In this context, in the method in accordance with the
invention, a medical cassette and/or an apparatus for treating a
medical liquid such as was/were already shown above is/are
advantageously used.
[0076] The present invention further relates to a method for
checking the leaktightness of a medical cassette made of a hard
part having liquid-conducting passages which are covered by a
flexible film, in particular before the filling of the medical
cassette, comprising the steps: coupling a medical cassette to a
coupling surface of a treatment machine, suction of air between the
flexible film and the coupling surface of the treatment machine
during the coupling process and/or with a coupled cassette, in
particular area suction, checking the leaktightness of the medical
cassette using the vacuum which arises, with the check of the
leaktightness taking place during and/or after the coupling of the
cassette. Since no vacuum can be built up in the case of a film
leak on the suction of the air, it is possible in accordance with
the invention to determine and to display too high a leak rate via
the vacuum monitoring and vacuum evaluation of the air suction. A
leak in the disposable film can thus above all be recognized
initially before the filling of the disposable and before starting
treatment. The defective disposable can thereby be replaced by an
intact one. There is thus the possibility due to the continuous
evacuation of determining leaks in the film and of replacing
defective disposables.
[0077] This is in particular facilitated by the areal suction of
the present invention. In contrast, self-sealings would occur
between the film and the mat without the areal suction, which would
make a check more difficult. With such a process, a medical
cassette and/or an apparatus for treating a medical liquid such as
have been described above can advantageously be used.
[0078] The applicant reserves the right to file divisional
applications to any aspect of the present invention described in
this application, and in particular also to those aspects which are
not the subject matter of the claims of the present application. In
particular, the present invention comprises the following aspects,
which are subject matter of the present application also on their
own and independently of the preceding description:
[0079] 1. An apparatus for treating a medical liquid which includes
a treatment machine having a coupling surface, with a cassette made
of a hard part having liquid-conducting passages which are covered
by a flexible film being able to be coupled to the coupling surface
of the treatment machine, characterized in that,
[0080] in the coupled state of the cassette, a layer of an
air-permeable porous material is arranged between the flexible film
and the coupling surface, at least in partial regions, and air can
be sucked out areally through said layer during the coupling
process and/or with a coupled cassette.
[0081] 2. An apparatus in accordance with aspect 1, wherein the air
can be sucked out through the layer of an air-permeable porous
material along the plane of the layer.
[0082] 3. An apparatus in accordance with either of aspects 1 or 2,
wherein the layer of an air-permeable porous material is arranged
directly on the flexible film in the coupled state of the
cassette.
[0083] 4. An apparatus in accordance with one of the aspects 1 to
3, wherein the layer of an air-permeable porous material includes a
nonwoven.
[0084] 5. An apparatus in accordance with one of the aspects 1 to
4, wherein the layer of an air-permeable porous material is
arranged over the whole area on the flexible film.
[0085] 6. An apparatus in accordance with one of the aspects 1 to
5, wherein the cassette is pressed with the coupling surface in the
coupled state, with the pressure transmitted over the layer made of
an air-permeable material orthogonally to its plane during the
coupling process and/or with a coupled cassette pressing the film
in a fluid tight fashion with the liquid-conducting passages of the
hard part of the cassette, but with the layer made of an
air-permeable material remaining air-permeable along its plane.
[0086] 7. An apparatus in accordance with anyone of the aspects 1
to 6, wherein the treatment machine has a flexible mat arranged on
the coupling surface, with the cassette being able to be coupled to
the coupling surface of the treatment machine via the flexible mat
and a layer of an air-permeable material being arranged between the
flexible film and the flexible mat in the coupled state of the
cassette.
[0087] 8. An apparatus for treating a medical liquid which includes
a treatment machine having a coupling surface and a flexible mat
arranged on the coupling surface, with a cassette made of a hard
part having liquid-conducting passages which are covered by a
flexible film being able to be coupled to the coupling surface of
the treatment machine via the flexible mat, characterized in
that
[0088] the flexible mat comprises an air-permeable material and is
configured such that air is sucked out in a region of the flexible
mat without interruptions during the coupling process and/or with a
coupled cassette, and indeed along the plane of the flexible mat
and/or through the flexible mat.
[0089] 9. An apparatus for treating a medical liquid which includes
a treatment machine having a coupling surface, with a cassette made
of a hard part having liquid-conducting passages which are covered
by a flexible film being able to be coupled to the coupling surface
of the treatment machine, characterized in that
the surface of the flexible film has a structuring through which
air can be sucked out along the structuring of the film during the
coupling process and/or with a coupled cassette.
[0090] 10. An apparatus for treating a medical liquid which
includes a treatment machine having a coupling surface and a
flexible mat arranged on the coupling surface, with a cassette made
of a hard part having liquid-conducting passages which are covered
by a flexible film being able to be coupled to the coupling surface
of the treatment machine via the flexible mat, characterized in
that
the surface of the flexible mat facing the flexible film has a
structuring through which air can be sucked out along the
structuring of the flexible mat during the coupling process and/or
with a coupled cassette.
[0091] 11. An apparatus in accordance with either of aspects 9 or
10, wherein the structuring has a net structure and/or a
meander-like and/or linear structure.
[0092] 12. An apparatus in accordance with either of aspects 9 or
10, wherein the structuring is made anisotropoic and/or
inhomogeneous.
[0093] 13. An apparatus in accordance with either of aspects 9 or
10, wherein the structuring extends along the liquid-conducting
passages.
[0094] 14. An apparatus in accordance with aspect 13, wherein the
structuring converges in one or more regions outside the
liquid-conducting passages which form suction points.
[0095] 15. An apparatus in accordance with one of the aspects 9 to
14, wherein the structuring extends substantially perpendicular to
the passage web edge on the transition from the region with
liquid-conducting passages to the region outside the
liquid-conducting passages.
[0096] 16. An apparatus in accordance with one of the aspects 13 to
15, wherein the structuring has a spacing from the passage web
edges in the regions in which it does not traverse the passage web
edges.
[0097] 17. An apparatus in accordance with one of the aspects 13 to
16, wherein the structuring is made such that there is no direct
connection between regions of the film with different
liquid-conducting passages.
[0098] 18. An apparatus in accordance with one of the aspects 9 to
17, wherein the cassette is pressed with the coupling surface in
the coupled state, with the film being pressed in a fluid-tight
manner with the liquid-conducting passages of the hard part of the
cassette, but with the structuring along its plane allowing air
transport.
[0099] 19. An apparatus for treating a medical liquid which
includes a treatment machine having a coupling surface and a
flexible mat, in particular a silicone mat, arranged on the
coupling surface, with a cassette made of a hard part having
liquid-conducting passages which are covered by a flexible film
being able to be coupled to the coupling surface of the treatment
machine via the flexible mat, characterized in that
air can be sucked out along a plane between the flexible film and
the surface of the flexible mat facing the flexible film during the
coupling procedure and/or with a coupled cassette.
[0100] 20. An apparatus in accordance with one of the preceding
aspects comprising at least one suction device.
[0101] 21. An apparatus in accordance with aspect 20, wherein the
air-conducting layer is in communication with a vacuum device at
one or more points outside the region of the liquid-conducting
passages.
[0102] 22. An apparatus in accordance with one of the preceding
aspects, wherein the suction takes place via at least one valve
arranged in the coupling surface of the treatment machine.
[0103] 23. An apparatus in accordance with one of the preceding
aspects, wherein the suction takes place via one or more suction
openings arranged in the hard part of the cassette.
[0104] 24. An apparatus in accordance with one of the preceding
aspects, comprising an optical sensor for the recognition of leaks,
in particular by scattered light wetting detection.
[0105] 25. An apparatus in accordance with one of the preceding
aspects, comprising a control which carries out an automatic
suction of the air.
[0106] 26. An apparatus in accordance with aspect 25, wherein the
control carries out an automatic check of the leaktightness of the
medical cassette.
[0107] 27. An apparatus in accordance with one of the preceding
aspects, comprising a medical cassette in accordance with one of
the following aspects.
[0108] 28. A medical cassette made of a hard part having
liquid-conducting passages which are covered by a flexible film,
with the cassette being able to be coupled to the coupling surface
of the treatment machine, characterized in that
a structure is arranged on the flexible film through which air can
be sucked out along the plane of the film surface during the
coupling process and/or with a coupled cassette.
[0109] 29. A medical cassette in accordance with aspect 28, wherein
a layer of an air-permeable material, in particular porous
material, through which air can be sucked out areally along the
plane of the material layer in the coupled state of the cassette is
arranged on the flexible film at least in part regions.
[0110] 30. A medical cassette in accordance with aspect 29, wherein
the layer of an air-permeable porous material is arranged over the
whole area on the flexible film.
[0111] 31. A medical cassette in accordance with either of aspects
29 or 30, wherein the layer of an air-permeable material is welded
to the cassette in a peripheral marginal region.
[0112] 32. A medical cassette in accordance with aspect 31, wherein
the weld forms a gas-tight barrier along the plane of the layer of
an air-permeable material.
[0113] 33. A medical cassette in accordance with one of the aspects
28 to 32, wherein the layer of an air-permeable material is welded
to the hard part of the cassette.
[0114] 34. A medical cassette in accordance with either of aspects
28 or 29, wherein the hard part of the cassette has a peripheral
marginal region into which the structure, in particular the layer
of an air-permeable material, does not extend so that this marginal
region forms a sealing web on pressing.
[0115] 35. A medical cassette in accordance with aspect 34, wherein
the flexible film is welded to the hard part of the cassette in the
peripheral marginal region.
[0116] 36. A medical cassette in accordance with aspect 29, wherein
the layer of an air-permeable material is connected, in particular
adhesively bonded and/or spot welded and/or pasted and/or laminated
and/or tacked to the film.
[0117] 37. A medical cassette in accordance with either of aspects
28 or 29, wherein the pressure transmitted during the coupling
process and/or with a coupled cassette via the structure, in
particular via the layer of an air-permeable material, orthogonally
to its plane presses the film with the liquid-conducting passages
of the hard part of the cassette in a fluid-tight manner, but the
structure, in particular the layer of an air-permeable material
remains gas-permeable along its plane.
[0118] 38. A medical cassette in accordance with aspect 29, wherein
the layer of an air-permeable porous material includes a
nonwoven.
[0119] 39. A medical cassette in accordance with aspect 28, wherein
the surface of the flexible film has a structuring through which
air can be sucked out along the plane of the film in the coupled
state of the cassette.
[0120] 40. A medical cassette in accordance with aspect 39, wherein
the structuring has a net structure and/or a meander-like structure
and/or a linear structure.
[0121] 41. A medical cassette in accordance with either of aspects
39 or 40, wherein the structuring is made anisotropic and/or
inhomogeneous.
[0122] 42. A medical cassette in accordance with either of aspects
39 or 40, wherein the structuring extends along the
liquid-conducting passages.
[0123] 43. A medical cassette in accordance with aspect 42, wherein
the structuring converges in one or more regions outside the
liquid-conducting passages which form suction points.
[0124] 44. A medical cassette in accordance with one of the aspects
28 to 43, wherein the structuring extends substantially
perpendicular to the passage web edge on the transition from the
region with liquid-conducting passages to the region outside the
liquid-conducting passages.
[0125] 45. A medical cassette in accordance with one of the aspects
42 to 44, wherein the structuring has a spacing from the passage
web edges in the regions in which it does not traverse the passage
web edges.
[0126] 46. A medical cassette in accordance with one of the aspects
42 to 45, wherein the structuring is made such that there is no
direct connection between regions of the film with different
liquid-conducting passages.
[0127] 47. A medical cassette in accordance with one of the
preceding aspects, wherein the hard part has containment webs which
connect the passage rim sealing webs and form areas sealing pressed
closed.
[0128] 48. A medical cassette in accordance with one of the
preceding aspects, comprising at least one suction opening arranged
in the hard part of the cassette.
[0129] 49. A medical cassette in accordance with aspect 48, wherein
the suction opening is arranged outside the region of the
liquid-conducting passages.
[0130] 50. A medical cassette in accordance with aspect 48, wherein
the flexible film is welded to the hard part of the cassette around
the suction opening.
[0131] 51. A medical cassette in accordance with aspect 50, wherein
the annular weld seam has a structuring around the suction
opening.
[0132] 52. A medical cassette in accordance with aspect 50, wherein
the region of the weld seam is lowered with respect to the pressing
plane of the cassette.
[0133] 53. A medical cassette in accordance with aspect 48, wherein
a hydrophobic filter is arranged at the suction opening.
[0134] 54. A method for coupling a cassette made of a hard part
having liquidconducting passages which are covered by a flexible
film to the coupling surface of a treatment machine for treating a
medical fluid comprising the steps: [0135] coupling the medical
cassette to the coupling surface of the treatment machine; [0136]
suction of air between the flexible film and the coupling surface
of the treatment machine during the coupling process and/or with a
coupled cassette, characterized in that the suction takes place
areally via a layer of an air-permeable porous material arranged at
least in part regions between the flexible film and the coupling
surface.
[0137] 55. A method for coupling a cassette made of a hard part
having liquid-conducting passages which are covered by a flexible
film to the coupling surface of a treatment machine for treating a
medical fluid comprising the steps: [0138] coupling the medical
cassette to the coupling surface of the treatment machine via a
flexible mat arranged on the coupling surface; [0139] suction of
air between the flexible film and the flexible mat during the
coupling process and/or with a coupled cassette, characterized in
that the suction takes place in regions of the flexible mat without
interruptions, and indeed along the plane of the flexible mat
and/or through the flexible mat, for which purpose the mat
comprises an air-permeable material.
[0140] 56. A method for coupling a cassette made of a hard part
having liquid-conducting passages which are covered by a flexible
film to the coupling surface of a treatment machine for treating a
medical fluid comprising the steps: [0141] coupling the medical
cassette to the coupling surface of the treatment machine; [0142]
suction of air between the flexible film and the coupling surface
of the treatment machine during the coupling process and/or with a
coupled cassette, characterized in that the suction takes place
along a structuring of the surface of the flexible film and/or
along a structuring of a surface of a flexible mat facing the
flexible film via which the cassette is coupled to the coupling
surface.
[0143] 57. A method for coupling a cassette made of a hard part
having liquidconducting passages which are covered by a flexible
film to the coupling surface of a treatment machine for treating a
medical fluid comprising the steps: [0144] coupling the medical
cassette to the coupling surface of the treatment machine via a
flexible mat arranged on the coupling surface; [0145] suction of
air between the flexible film and the flexible mat during the
coupling process and/or with a coupled cassette, characterized in
that the suction takes place along the plane between the flexible
film and the surface of the flexible mat facing the flexible
film.
[0146] 58. A method in accordance with anyone of the aspects 54 to
57, comprising a medical cassette and/or an apparatus for treating
a medical liquid in accordance with one of the aspects.
[0147] 59. A method for checking the leaktightness of a medical
cassette made of a hard part having liquid-conducting passages
which are covered by a flexible film, in particular before the
filling of the medical cassette, comprising the steps: [0148]
coupling the medical cassette to a coupling surface of a treatment
machine; [0149] suction of air between the flexible film and the
coupling surface of the treatment machine, in particular areal
suction during the coupling process and/or with a coupled cassette;
[0150] checking the leaktightness of the medical cassette with
reference to the created vacuum, wherein the check of the
leaktightness takes place during and/or after the coupling of the
cassette.
[0151] 60. A method in accordance with aspect 59, comprising a
medical cassette and/or an apparatus for treating a medical liquid
in accordance with one of the preceding aspects.
BRIEF DESCRIPTION OF THE DRAWINGS
[0152] The present invention will now be shown in more detail with
reference to embodiments and to drawings. There are shown:
[0153] FIG. 1: an apparatus for treating a medical liquid in
accordance with the prior art;
[0154] FIG. 2: an apparatus for treating a medical liquid in
accordance with a first embodiment of the present invention;
[0155] FIG. 3: an apparatus for treating a medical liquid in
accordance with a second embodiment of the present invention;
[0156] FIG. 4: a plan view as well as a sectional view of a
structuring in accordance with a third embodiment of the present
invention;
[0157] FIG. 5a: a plan view of a medical cassette in accordance
with a fourth embodiment of the present invention;
[0158] FIG. 5b: a sectional view through a structuring in a region
with sealing webs;
[0159] FIG. 5c: a sectional view through an embodiment of a suction
opening in accordance with the invention; and
[0160] FIG. 6: an apparatus for treating a medical liquid in
accordance with a fifth embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0161] Further scope of applicability of the present invention will
become apparent from the detailed description given hereinafter.
However, it should be understood that the detailed description and
specific examples, while indicating preferred embodiments of the
invention, are given by way of illustration only, since various
changes and modifications within the spirit and scope of the
invention will become apparent to those skilled in the art from
this detailed description.
[0162] FIG. 1 shows an apparatus for treating a medical liquid such
as is used in the prior art, e.g. for hemodialysis or peritoneal
dialysis. Such apparatus can, however, also be used in a plurality
of other fields of application in which a disposable cassette,
which is also called a disposable, is used and is coupled to
sensors and actuators of a treatment machine via a coupling
surface.
[0163] The treatment machine 1 has a coupling surface 10 on which a
sensor 11 is arranged by way of example. The cassette 2 includes a
hard part 20 having a liquid-conducting passage 21 which is covered
by a flexible film 25, with the liquid-conducting passage being
separated in fluid-tight manner inside the cassette via laterally
arranged sealing webs 22 which are pressed with the flexible film
25. In this connection, the sensor 11 is disposed opposite the
liquid-conducting passage 21 which thus forms a measuring chamber,
in the case of a pressure sensor a pressure measuring chamber.
[0164] Furthermore, a flexible silicone mat 15 is arranged between
the film 25 and the coupling surface 10 of the treatment machine 1
on the machine side to protect the sensor surfaces of the sensor 11
from environmental influences. In addition, the machine surface is
hereby hermetically sealed and thus ideally hygienically cleanable.
Alternatively, however, the silicone mat 15 can also be dispensed
with so that the film 25 directly contacts the coupling surface 10
of the treatment machine 1.
[0165] The difficulty exists with the coupling of sensors to the
film disposable 2, however, of coupling the film 25 to the sensor
surface of the sensor 11 such that correct measured values are
obtained. In particular air which is enclosed in the transmission
path between the disposable film 25 and the sensor surface on the
insertion of the cassette produces a falsification of the measured
results. This applies to pressure sensors, but also e.g. in level
detection and likewise to actuators such as valves which control
the liquid flows inside the cassette via a pressing of the flexible
film 25 into the liquid-conducting passages 21 of the hard part
20.
[0166] A first embodiment of the present invention is now shown in
FIG. 2. In this context, an areal structure between the film 25 and
the mat 15 permits an areal air suction along the coupling plane.
It can hereby be ensured that the space between the film 25 and the
mat 15 is reliably vented without air islands remaining enclosed
and falsifying the measured results due to a self-sealing by
applying the film 25 to the mat 15.
[0167] In the embodiment shown in FIG. 2, the areal suction is
achieved in that a layer 30 of an air-permeable, in particular
porous, material, in this case a nonwoven layer, is inserted
between the film 25 and the mat 15. Such a nonwoven layer is porous
due to its structure, that is air can flow in the surface in this
layer even if the total composite of film 25, nonwoven 30 and mat
15 is strongly pressed e.g. by the sealing webs 22.
[0168] A connection is thus obtained between the film 25 and the
hard part 20 which is pressed in a fluid-tight manner, with the
layer 30 of an air-permeable material, in particular porous
material, nevertheless remaining permeable for air. It is thus
sufficient to contact the space between the film 25 and the mat 15
at a single point with a vacuum system 13 in a fluid manner via a
suction opening 28 to vent the total space between the film 25 and
the mat 15 reliably and areally. A plurality of sensors 11 or
actuators can hereby be coupled reliably and air-free to the film
25. The connection of the nonwoven space with the vacuum system can
in this manner also be used directly after the pressing for a film
leaktightness test such as would not be possible without such an
air conducting layer.
[0169] The suction opening 28 is integrated in the hard part 20 of
the cassette in the first embodiment and has a hydrophobic membrane
24 in the suction passage which is likewise integrated into the
hard part. A contamination of the machine can hereby be prevented
in the defect case of a film rupture. The suction opening 28 in the
hard part 20 of the cassette is connected via a sealing element 14
to suction channels which are integrated in the machine door 12 and
are in turn in communication with a vacuum system 13 on the
insertion of the cassette into the treatment machine. The films has
a peripheral weld with the hard part around the suction opening 28.
In this context, the region of the peripheral weld is lowered with
respect to the pressing level of the cassette so that the weld of
the nonwoven 30 with the hard part does not represent a barrier for
the air suction.
[0170] The fluid contacting of the nonwoven space takes pace
outside the liquidconducting areas of the passage structure 21. A
failure of the weld between the film and the hard part around the
suction opening thus only results in a contamination of the
hydrophobic membrane 24 on a simultaneous film rupture on a passage
point or a simultaneous failure of a sealing web 22.
[0171] A second embodiment of the present invention is shown in
FIG. 3 in which the fluid contacting does not take place starting
from the hard part 20, but rather from the mat side. In this
connection, an opening is provided in the mat 15 and is in fluid
communication with the vacuum system 13 via a valve 16. The
contacting of the air-conducting layer 30 also takes place outside
the region of the liquid-conducting areas of the passage structure
21 here. The hard part 20 has a plunger 29 which opens the valve 16
on the insertion of the cassette into the treatment machine. The
cassette has a peripheral sealing web 27 at which no nonwoven layer
30 is provided so that an outwardly closed space arises between the
film 25 and the mat 15 from which the air can be sucked out without
leak air flowing in from the outside. Alternatively to the
arrangement shown in FIG. 3, an excessive intrusion of leak air
into the system can also take place by other designs of a
peripheral sealing rim. The fact can e.g. be utilized in this
context that the nonwoven structure is modified on the welding of
the nonwoven 30 to the film 25 such that a gas-tight barrier is
created. A nonwoven 30 made air-impermeable can therefore be
pressed with the silicone mat 15 at this point in an airtight
manner. This welding ideally takes place in a single workstep
together with the welding of the film with the hard part 20. For
this purpose, it is advantageous to produce the nonwoven 30 from a
material, e.g. from PP, which can welded with the hard part 20.
[0172] A further possibility comprises cutting out the nonwoven to
be smaller than the film so that a seal can be provided
peripherally directly between the film and the silicone mat. The
fastening of the nonwoven 30 to the film can take place in this
case e.g. by adhesive bonding and/or spot welding and/or pasting
and/or laminating and/or tacking. It is moreover possible to
connect the film and the nonwoven in a first workstep and then to
establish the connection to the hard part in a second step.
[0173] Alternatively to the use of the nonwoven shown in the first
and second embodiments, the air transport in the desired plane can
be achieved in that the surface of the film 25 is structured such
that an air-conducting layer arises in the film itself. This can
take place, for example, by stamping a structure into the film.
[0174] In this context, in a third embodiment, a grid-like
structure can be pressed into the film so that a network of
passages arises in the film which are separated from one another by
regions of thicker material. Different geometries are conceivable,
with FIG. 4 showing a honeycomb structure by way of example. It is
also possible to realize an anisotropic suction by the selection of
the suitable structure in that e.g. the passages are made larger
from left to right than from top to bottom. The structure on the
surface can also be inhomogeneous in design. The structure can
likewise be of meander shape.
[0175] In this context, the geometry of the passages being created
is important for the achievable suction power. Narrow, deep
passages are not closed by the silicone mat on pressing so that a
suction through the passages remains possible. The shallower the
passages are, the higher the risk of sealing by a partial
application of the film to the mat in the passages. If the passages
become too wide, the risk increases that the pressing on the smooth
side of the film (toward the blood side and the hard part) becomes
too inhomogeneous and that leaks arise on this side. Further
production processes for the manufacture of the structurings of the
surface of the film are available in addition to stamping. A
structure can e.g. also be introduced into the film surface
directly in the extrusion of the film.
[0176] Alternatively, such a structuring could also be arranged in
the surface of the mat 15 facing the film 30. A reliable air
suction could also hereby be made possible. However, it is a
disadvantage of such an arrangement that the surface of the mat is
then no longer smooth and so a cleaning of the mat surface is made
difficult.
[0177] It is alternatively likewise possible to dispense with the
silicone mat 15 on the use of a nonwoven 30 or of a structuring of
the film surface so that the nonwoven 30 is arranged directly
between the film 25 and the coupling surface 10 of the treatment
machine or the structured surface of the film 25 directly contacts
the coupling surface 10 of the treatment machine.
[0178] On the full area structuring of the cassette film or by
generating a full area drainage layer between the film plane and
the coupling plane, the total film area of the cassette up to the
peripheral film weld seam A or up to the outer peripheral sealing
web B (produced at the cassette side or at the machine side) is
made passable for gases and liquids beyond all the regular passage
rim sealing webs C. On the initial integrity test, it is therefore
necessary to evacuate the whole area and the leaktightness of the
peripheral sealing web must also be ensured parallel to the
actually desired leaktightness of the passage rims so that the
treatment can be enabled. The air quantity to be sucked out
initially for this purpose and the time required for this purpose
are thereby increased and the detection reliability for the
relevant film ruptures is lowered.
[0179] A fourth embodiment of the present invention is therefore
shown in FIG. 5a in which an internal structure of the structured
surface of the film is used. Only the liquid-wetted film areas
required from a technical process aspect are made capable of
drainage in the internal structure. The pressing between the outer
side of the film and the coupling plane is significantly lower than
the pressing on the passage rim sealing webs and in the non-liquid
areas G and H. In these latter areas, the cassette has flat sealing
bases parallel to the film. Whereas the passage rim sealing webs
are configured such that the liquid cannot overflow in the normal
case, the areas G and H are configured such that liquid which has
penetrated does not find any space since the pressing of the rubber
mat effects an approximately full contact of the film both to the
cassette plane and to the lowered rubber plane.
[0180] Since the pressing between the film and the rubber mat is
significantly lower in the liquid-wetted internal areas S1, S2 and
S3 than the pressing in all other areas of the film zone, a much
less pronounced drainage structure is sufficient in this area both
to ensure the complete film coupling and to ensure the complete
detection of the relevant film surface with respect to possible
ruptures. A safety spacing E of the structure 0 of approximately up
to 1 mm can therefore be provided in the internal structure to the
passage web edges C.
[0181] The areas G and H are covered by the sterilization process
and hermetically sealed toward the outer world. If now a rupture
nevertheless occurs in the region of the area G during the
treatment, that is after an initial integrity test without
findings, this as a rule remains without consequence for the
treatment since the relevant areas S are not affected and since
there is no possibility of the liquid entering into the area G. If
a rupture occurs at a passage sealing web and beyond it, as
sketched by F, the functions of the self-sealing come into effect
due to the high pressings between the smooth film and the smooth
rubber mat and furthermore due to the additional pressing on the
peripheral rim. If a rupture occurs in the internal areas 8 during
the treatment, the leak fluid penetrates into the space between the
film and the rubber mat, further reduces the pressing and is
finally pressed up to and onto the suction point K along the
anisotropic structure D. Even the collection area H is only
insignificantly filled with leak fluid in this context since the
path over the direct conducting paths I to the suction point K
offers the lowest flow resistance.
[0182] The internal structure provides less detection time and
higher detection accuracy in the integrity test before the filling
with treatment liquid. The internal structure provides redundant
passive leak protection in the first defect case of the film
rupture during treatment. The internal structure provides a much
smaller area of the film and rubber mat which can be wetted on film
rupture and which can, vice versa, contribute to the contamination
of the treatment surface in the treatment liquid. The internal
structure can increase the reliability and reduces the detection
time of an occurring film rupture during the treatment and thus
increases the security against contamination and
cross-contamination. The internal structure can reduce the
probability and the extent of possible liquid losses to the
outside.
[0183] The possibility of an anisotropic structure furthermore
results: An anisotropic film structure or an anisotropic design of
interspersed drainage layers means designing the intensity, the
direction, the functionality and the non-presence of the drainage
effect locally differently. This includes the previously described
internal structure with an unstructured marginal region toward the
passage sealing webs.
[0184] The next possibility is the deliberate provision of separate
structure areas 81 . . . 83 with a minimized number of crossings I
of passage sealing web regions. I also shows how a minimum of
volume has to be sucked out or wetted due to the optimized
structure in the case of the initial test and in the case of a
leak.
[0185] The sectional representation FIG. 5b shows the optimized
effect of linear structures which cross the passage rim sealing
webs in perpendicular manner. An optimum of pressing leaktightness
on the liquid side can be linked with an optimum obtaining of
drainage structure depth on the machine side by this arrangement.
The two basically negative designs of structures are shown with
extreme exaggeration in the Figure, namely a partial squeezing
closure U of the structure passages 0 and a pressing V interrupted
by the inhomogeneous force conduction at the passage rim sealing
webs C. Structures crossing the sealing webs in parallel or
obliquely would penetrate further into the web and into the rubber
mat and thus more greatly reduce the drainage effect and the
pressing effect.
[0186] It must also be considered that it may be necessary at
certain points, for example for the optical measurement of the
liquid turbidity, or at passage points for ultrasound, that the
film remains smooth and/or translucent. In this case, a window is
provided by omission of structure or of drainage layers.
[0187] Possibilities furthermore result by the use of containment
webs. If connection webs J are added between the passage rim
sealing webs at suitable points of the passage and chamber layout,
new areas H sealing pressed closed are obtained. If the drainage
structures converge in this area, this area H forms the total area
together with the liquid areas S1 . . . S3 which is detected for
film rupture before and during the treatment and which has a
passively sealing pressed passage rim as an areal boundary for the
conceivable leak fluid or for the conceivable contamination and
cross-contamination. Each leak must finally reach this area H and
this is the preferred location for suction points K with leak
detectors and with hydrophobic contamination membranes.
[0188] Containment webs furthermore provide the possibility of
somewhat reducing the pressing sealing effect at the points of the
crossings I of the drainage structures over the passage sealing
rims in favor of a better drainage effect (for example by a
widening of the passage rim sealing webs) without outwardly
reducing the effect of the reliable pressing leaktightness.
[0189] The present invention furthermore provides the possibility
of a non-invasive blood leak detection: The decision to cover the
coupling plane of the machine with a closed protective layer, for
instance of rubber, requires the consequence of also making a leak
detector for the early discovery of film ruptures during the
treatment as a device working in a non-invasive manner. This is,
for example, possible through a thin rubber mat via capacitive
sensors, via ultrasonic sensors or via the detection of the vacuum
collapsing on a leak. This is possible via optical sensors with a
reflection arrangement on the side of the mating coupling plane (to
the nonfilm side of the cassette). A color sensor can, for example,
distinguish in this context whether blood has exited or whether it
is a normal moisture. The structure of the film can be utilized
here to install a scattered light wetting detection. With a dry
film, scattered light is reflected back at the structure which is
absent if the structure is liquid-wetted. With such an arrangement
on the non rubber mat side, the necessity for a sensor-sensitive
special design of the rubber mat is therefore dispensed with.
[0190] Possibilities furthermore result due to specially structured
weld seams and rubber mats: The problem in particular arises at the
suction point K due to the annular weld seams required for this
purpose around the hydrophobic membrane and around the hydrophobic
membrane cut-out or the suction hole cut-out in the film that both
a structure of the film and a welding on a drainage layer (for
instance made of a nonwoven) disposed thereabove are leveled by an
annular weld seam and thereby form annular barriers between the
areas H and K.
[0191] To cancel these barrier possibilities, FIG. 5c shows a
combination of four possible measures. A dent Q in the rubber mat
equally reduces the sealing pressing against the annular weld seam
as a dent R in the cassette surface. A further similar effect is
achieved by the local structure S of the rubber mat in the region
of the dent with grooves and patterns which radially bridge the
weld seam at a plurality of points with a drainage effect.
[0192] The disadvantage of a worsened cleaning capability of the
rubber mat results with both rubber mat measures. The counterpart
to a structure of the rubber mat in the region of the suction point
is a structure of the annular weld seam. For this purpose, the
welding stamp is configured to be annular, but this ring is made
more pronouncedly conically than the associated weld surface of the
cassette. The annular surface M is furthermore equipped with
radially arranged drainage ribs which leave a common structure of
the cassette base and the film during welding, said common
structure having a serrated annular surface with radially outwardly
facing linear structures which extend up to and into the unwelded
film regions after the welding due to the conical shape of the
annular surface association, said linear structures form a total
structure together with the radial structures already present there
which is no longer interrupted by the annular sealing weld
zone.
[0193] FIG. 6 now shows a fifth embodiment of the apparatus for
treating a medical liquid of the present invention in which the
suction does not take place by an additional nonwoven between the
flexible film 25 and the flexible mat 15 or by a corresponding
structuring, but rather by the suitable choice of the mat material
via the flexible mat 15 itself. For this purpose, the flexible mat
comprises an air-permeable material (e.g. silicone) such that the
air between the flexible mat 15 and the flexible film 25 can be
sucked out directly through the mat 15 itself via the vacuum
applied to the suction passages 40. The wide area distribution of
the vacuum takes place in this context via the air passages 40 in
the machine plate, whereas the permeable mat then permits an areal
suction over the total surface. A complete closure of the suction
is also practically precluded by this areal design.
[0194] In this embodiment, an already known medical cassette 2 made
of a hard part 20 having liquid-conducting passages 21 can be used
which is sealed by the flexible film 25. For this purpose, as in
known systems, the medical cassette 2 is pressed with the flexible
mat 15 of the treatment machine so that the sealing webs 22 provide
a seal. In accordance with the invention, however, an areal suction
is now possible which takes place via the vacuum passages 40 and
via the permeable mat material on the machine side.
[0195] The mat material is advantageously air-permeable, but
liquid-tight, in this context to avoid contamination of the
coupling surface and to facilitate cleaning.
[0196] The possibility of determining leaks in the film moreover
results by the possibility in accordance with the invention of
sucking out air continuously between the flexible film 25 and the
coupling surface 10. No vacuum can be built up after the pressing
of the door in the case of a sufficiently large film leak due to
the areal evacuation.
[0197] Accordingly, air is constantly sucked out of the still
unfilled disposable into the intermediate space between the film
and the mat or the coupling surface. The too high leak rate can
then be determined and registered via the vacuum monitoring and the
vacuum evaluation. The check of the leaktightness can take place
during and/or after the coupling to the cassette.
[0198] A leak in the disposable film can thus above all be
recognized initially before the filling of the disposable and
before starting treatment. The defective disposable can thereby be
replaced by an intact one.
[0199] Without the areal suction, in contrast, such a check would
be less reliable since a self-sealing can arise between the film
and the mat and film leaks could still be present in regions with
enclosed air islands, which leaks would not be detected via the
vacuum monitoring and the vacuum evaluation. Basically, the check
in accordance with the invention can, however, be carried out with
any type of evacuation.
[0200] In this connection, the central idea of the invention is the
areal suction of the air between the flexible film and the coupling
surface, which is made possible by the different embodiments in
that an air-permeable layer, a structuring of the surface of the
flexible film and/or mat, a suction in the plane between the
flexible mat and the flexible film and/or a suction through a
permeable mat material is/are provided.
[0201] The invention being thus described, it will be apparent that
the same may be varied in many ways. Such variations are not to be
regarded as a departure from the spirit and scope of the invention,
and all such modifications as would be recognized by one skilled in
the art are intended to be included within the scope of the
following claims.
* * * * *