Cassette module

Abstract

The present invention relates to a cassette module for controlling fluid flows, in particular for use in blood treatment systems or in infusion systems, wherein the cassette module has at least one first functional layer and at least one second functional layer, wherein the first functional layer has means for the flow guidance of at least one fluid flow, and wherein the cassette module furthermore has at least two membranes of which the first is in contact with the means for the flow guidance of a fluid flow, and wherein the second functional layer is arranged between the two membranes and has means for generating an underpressure between the membranes.

Claims

1. A cassette module for guidance of fluid flows, the cassette module comprising a first functional layer, a second functional layer, and a third functional layer, wherein each of the first, second, and third, functional layers comprises a flexurally stiff material, and wherein the first functional layer has means for guidance of a fluid flow, a first membrane having at least one layer and a second membrane having at least one layer, wherein the second functional layer is arranged between the first and second membranes, wherein each of the first and second membranes is an elastic membrane, and wherein the first membrane cooperates with the means for guidance of a fluid flow, wherein the second functional layer is arranged between the first and second membranes and has means for generating an underpressure between the first and second membranes, and wherein the third functional layer has means for actuating the second membrane and with which the second membrane cooperates, and a movable plunger or plunger disk present between the first and second membranes for transmitting force from the first membrane to the second membrane.

2. A cassette module in accordance with claim 1, characterized in that the means for actuating the second membrane are pneumatic means or hydraulic means in which excess pressure or underpressure is present or can be generated.

3. A cassette module in accordance with claim 1, characterized in that the means for guidance of fluid flow has one or more channels, valve sections and pump sections.

4. A cassette module in accordance with claim 1, characterized in that the means for generating an underpressure between the first and second membranes comprises one or more channels which are or can be connected to a vacuum pump.

5. A cassette module in accordance with claim 1, characterized in that the first membrane directly or indirectly contacts the first functional layer, and the first and second membranes directly or indirectly contact the second functional layer.

6. A cassette module in accordance with claim 1, characterized in that the at least one second membrane directly or indirectly contacts the second and the third functional layers.

7. A cassette module in accordance with claim 1 characterized in that the plunger or plunger disk is configured such that it cooperates with the means for guidance of a fluid flow in at least one position.

8. A cassette module in accordance with claim 1, characterized in that at least one of (a) the cassette module has at least two edges arranged opposite or adjacent to one another, into which the means for generating an underpressure between the first and second membranes opens, and (b) the cassette module has at least one sensor intended for measurement of pressure present between the first and second membranes.

9. A machine, comprising at least one slot in which at least one cassette module in accordance with claim 1 is located, respectively, such that blood flow through the means for guidance of a fluid flow is controlled by deflection of the first and second membranes.

10. A machine in accordance with claim 9 further comprising at least one of underpressure generating means in communication with the means for generating an underpressure between the first and second membranes and at least one sensor present in at least one of the machine and the cassette module for measuring pressure between the first and second membranes or a parameter correlated therewith.

11. A cassette module in accordance with claim 1, characterized in that the means for actuating the second membrane are chambers or channels in which excess pressure or underpressure is present or can be generated.

Description

(1) Further details and advantages of the invention will be explained in more detail with reference to an embodiment shown in the drawing.

(2) The only FIGURES shows a longitudinal sectional view through a cassette module in accordance with the invention.

(3) The first functional layer is marked by the reference numeral 7 and the second functional layer is marked by the reference numeral 2.

(4) Reference numeral 1 marks the third functional layer.

(5) As can be seen from the FIGURE, the second functional layer 2 is located between the first functional layer 7 and the third functional layer 1.

(6) Furthermore, a first membrane 6 is located between the second functional layer 2 and the first functional layer 7 and a second membrane 5 is located between the third functional layer 1 and the second functional layer 2.

(7) Reference numeral 8 marks vacuum channels which extend through the second functional layer 2 and which have the purpose of providing or maintaining a vacuum between the two membranes 5, 6.

(8) As can furthermore be seen from the FIGURE, a respective one plunger or a respective one plunger plate 3 is located between the membranes 5, 6 in both chambers shown which equally serves as a valve for closing or releasing an opening 70, 70 in the first functional layer 7.

(9) In the state of the cassette module inserted into a machine, a vacuum is applied to the channel 8 by a vacuum pump or the like of the machine so that the two membranes 5, 6 tightly contact one another or tightly contact the plunger or the plunger plate 3.

(10) As can further be seen from the FIGURE, means for the flow guidance of at least one liquid flow such as blood, dialyzate, an infusion solution, etc. are located in the first functional layer 7, wherein in the embodiment shown here, the means are configured in the form of a valve which allows or prevents a throughflow of the chambers 14, 14 of the cassette module.

(11) As can further be seen from the FIGURE, the valve block or the cassette module designed as a valve block has two such valves, wherein the valve having the opening 70 in the chamber 14 of the cassette module shown at the left being open and the valve having the opening 70 in the chamber 14 of the cassette module shown at the right being closed.

(12) The opening of the valve takes place in that underpressure is generated in the pneumatic chamber 12 as shown by an arrow. This has the result that the second membrane 5 and, due to the vacuum present between the membranes, also the first membrane 6 as well as also the plunger plate 3 are moved upwardly, whereby the opening 70 is released by the membrane 6. A fluid flow through the fluid chamber 14 is thereby made possible. As already stated above, the terms excess pressure and overpressure do not necessarily mean absolute values relative to atmospheric pressure, but can also be understood as values relative to one another.

(13) It is thus conceivable, for example, that an underpressure in the chamber 12 does not only mean that vacuum is applied by a pump in the chamber. It can also mean that a liquid is flowed into the chamber 14 by the operation of the cassette without, however, actuation taking place against this in the chamber 12.

(14) The membranes 5, 6 are also deflected in this case and the chamber 12 represents the underpressure side with respect to the chamber 14 without vacuum necessarily having to be present in the chamber 12.

(15) The pressure in the functional layer 2 is lower than in the layers 1 and 14.

(16) In the chamber 12 of the cassette module shown at the left, in contrast, an excess pressure is generated, as is symbolized by the arrow shown which symbolizes the inflow of a pneumatic fluid, in particular of compressed air. The two membranes 5, 6 as well as also the plunger plate 3 shown at the right are thereby urged downwardly and the opening 70 is closed by means of the first membrane 6. The chamber 14 can thus not be flowed through by a fluid, as is indicated by the dashed arrows.

(17) The cassette module shown in the FIGURE is a valve block. Any desired other functionalities are generally also covered by the invention such as a pump function or the like.

(18) The functional layers 1, 2, 7 comprise a flexurally stiff plastic, i.e. a stable-shape plastic, whereas the membranes 5, 6 are designed as flexible, preferably elastic membranes so that the desired flow guidance can be set.

(19) It can further be seen from the FIGURE that both the first functional layer 7 and the third functional layer 1 have flared portions which form chambers 12, 14, 12, 14 which serve, on the one hand, for controlling the membranes via an actuator medium such as compressed air and, on the other hand, for controlling a fluid flow such as blood, dialyzate, infusate, etc.

(20) The cassette module shown is naturally not only suitable for controlling a liquid flow, but also, for example, to control a gas flow.

(21) The control via the chambers 12, 12 also does not necessarily have to take place using a gas or compressed air, but can rather likewise take place via a fluid, i.e. hydraulically.

(22) The valve shown or the plunger plate 3 is brought into the one or other end position by the excess pressure or underpressure in the chambers 12, 12 and closes or opens a fluid circuit or the opening 70, 70 with its side opposite the pneumatic system or hydraulic system in dependence on its instantaneous position.

(23) The end positions can, for example, be formed by surfaces or functional layers such as by the second functional layer. In the right chamber, the plate-shaped region of the plunger plate abuts the second functional layer so that an end position is thereby defined.

(24) The control circuit, for example the pneumatic circuit, and the fluid circuit, for example a circuit for conveying blood, dialyzate, etc., are reliably separated by the presence of two membranes 5, 6 so that no contamination can occur on the tearing of a membrane.

(25) Due to the fact that there is a vacuum present between the membranes 5, 6 and the one membrane thus follows the movement of the other membrane, a reliable opening of the valve or of the opening 70, 70 can also be achieved when underpressure is present on the fluid side, i.e. on the side of the chamber 14, 14 or of the opening 70, 70. Otherwise, the case could occur that, with a closed valve and an applied underpressure, the passage 70, 70 could no longer be opened by applying underpressure in the chamber 12, 12.

(26) The two membranes 5, 6 are preferably only connected to one another by the application of an underpressure.

(27) The membrane 5 is preferably in direct contact with the functional layers 1 and 2 and the membrane is preferably in direct contact with the functional layers 2 and 7.

(28) It is generally also possible to provide additional coupling means, such as a weld, via which the membranes can be connected to one another. A preferred embodiment of the invention, however, comprises fully dispensing with the named weld.

(29) At least one sensor is preferably provided in the channel 8 or in a line element connected thereto and said sensor can measure the pressure and/or the flow in the channel. It is thus possible to be able to recognize a rupture of either the membrane 5 or the membrane 6 or of both membranes at an early stage, preferably by the machine, and particularly preferably directly after the upgrading and still before the start of treatment. A rupture can, however, also be recognized via a variable power pick-up of the vacuum pump means which is connected to the functional layer.

(30) If it is, for example, found that the desired vacuum cannot be maintained in the channel 8 and thus also not in the regions located between the membranes 5, 6, this can be due to the fact that a rupture is present in one or both of the membranes 5, 6. In this case, the cassette module preferably designed as a disposable is to be replaced with a functional module.

(31) It is pointed out at this point that the term membrane is to be understood widely and covers any areal and movable material which can carry out the named functions. The membranes can, for example, be configured as films.

(32) They are preferably not permeable for the fluid or also for the actuator medium. There are furthermore preferably largely impermeable for gas so that the vacuum can be easily maintained.

(33) Further advantages of the invention comprise an increased security of the valve function shown also being present on possible welding defects on the connecting of the membranes 5, 6, no partial closure of the fluid channel by a sagging film being able to be present in the case of underpressure and a complete omission of the welding process of the films to the valves being possible.

(34) The movement or valve function exerted by the second membrane 5 takes place faster and more precisely due to the plunger disk 3 located between the membranes 5, 7. This allows higher clock rates of the valve switching, which is desirable.