Untitled record

<img file="AT293343B_D0001.tif" />

AUSTRIAN

Class: 12 c₃ 1/10

PATENT OFFICE

Int. Cl .:

B 01 d 13/00

PATENT NUMBER NO. 293343 Issue Date October 11, 1971

DR. MED. JOSEF HOELTZENBEIN IN MÜNSTER (GERMANY) Plate dialyzer made of congruently stacked plates

Registered on November 28, 1969 (A 11155/69); Claimed priority: Claim 1 of 7 December 1968 (G 68 10 380), Claims 2.4-8 of 26 June 1969 (19 38 008.6) and Claim 3 of 27 December 1968 (G 68 13 222) (applications in Germany).

Beginning of the patent period: 15.Feber 1971.

The invention relates to a plate dialyzer with congruently stacked liquid-conducting plates and membranes arranged therebetween.

Dialyzers have a wide range of applications. They are used for the separation of liquids of dissolved substances, in particular for the separation of colloids and therein 5 molecular disperse substances with a smaller particle diameter. In modified embodiments, these plate dialyzers can also for the mass transfer between liquids and gases, eg as artificial lungs, as a guest exchanger, for example in the form of artificial gills, or as a heat exchanger between two fluid media, depending on the choice of the membrane, which separate the mutually exchange in mass transfer or heat exchange media from each other, are used. A particular area of ​​application for plate dialysers is extracorporeal hemodialysis. Hiebei a semipermeable membrane takes over the task of the physiological filter of the glomerulus capillaries. Hiebei takes place according to the laws of osmosis and diffusion, a mass transfer between the one hand applied to the membrane blood film and a flushing on the other side of the membrane rinse instead. This use of the plate dialyzer as an artificial kidney 15 is becoming increasingly important, for which reason special reference is made below to a blood dialyzer.

In artificial kidneys, it is important to keep the one hand, the blood volume as low as possible to save additional aggregates such as pumps or heaters and blood loss largely avoided, and on the other hand make the flow paths within the dialyzer so that a laminar as possible Blood flow and the shortest possible bloodstream can be achieved to prevent blood damage.

It is particularly difficult to seal the dialysis fluid paths of a plate dialyzer against each other. This is not least due to the fact that, especially in blood dialyzers as a material for the membranes, cellophane glass is used which, as a result of softening, does not adhere with water to the dialyzer plates, can be welded or connected in a similar manner. In known Blutdialysatoren simpler design, the blood is introduced via a branched channel system in grooves of the dialyzer plates, which are each covered by membranes. In the grooves of the adjacent plate while the rinse solution flows, so that a mass transfer between blood and rinsing solution can be made only on the one-sided contact surface with the membranes, while the blood is on a much larger surface in foreign contact with the inactive dialyzer plates. The efficiency of such dialyzers is very low in relation to the blood filling volume and, in addition, the resistance to the blood in the branched pathways is great.

It is therefore desirable in blood dialyzers to allow the blood to flow as a thin film between two membranes, so that much larger contact surfaces for the mass transfer 35 are available. With such dialyzers, however, there is still a much greater difficulty, the - 2 -

Nr.293343

To seal blood space between the membranes. This is the case in particular at the points where the blood enters between the membrane, which are each again arranged between two dialyzer plates. Plate dialyzers are known from congruently stacked plates, each with a profiled and a smooth surface, wherein each of the covered by the membranes profiled surfaces on the one hand and the smooth surfaces on the other hand are facing each other, arranged in cover plates at diametrically opposite corners of the plate stack inlet and outlet nozzles for the rinsing liquid and each one located in the end face opposite end plates located inlet and outlet channel for the liquid to be dialyzed and seals on the long sides.

In such known dialyzers therefore special connection and distribution pieces are sealed in the blood space between two adjacent plates. For this purpose, the plates have recesses into which the connection and distribution pieces can be inserted in a form-fitting manner. This arrangement requires above all the disadvantage that such dialyzers have a large height and also the assembly requires tedious operations as a result of inserting the individual connection and distribution pieces. It has also already placed the membrane directly on the profiled plates, but also in these designs special operations for profiling the end edges of the plates are necessary to insert in this the membrane ends under appropriate folds and seal individually.

It has also been proposed, irrespective of one of the two fastenings of the membrane edges, to provide the edges of the profile plates which are adjacent to the plate stacks of channels with bevelled edges.

The invention solves the problem of sealing the dialyzer plates and the membrane directly by simple stacking reliable against each other, so without any help from spacers or special profiling and sealing of the plates or mambranes. The solution to this problem is that in the described type of plate dialyzers, the surface profiles in a conventional manner consist of parallel grooves and each dialyzing membrane is guided around two opposite end faces of a profile plate and the membrane ends in each case between surface parts of two adjacent plates sealing are trapped.

An improvement of this invention is that the plates have chamfered edges per se known per se on their profiled front sides towards the plate stack upstream channels, forming wedge-shaped leading channels to the channels in such a way that the membrane ends wrap around these bevelled edges and their then ends are then sealed in the main plate plane. This new embodiment allows numerous advantageous developments. The sealing of the plates of the stack by means of the elastic membrane ends is further improved by itself in that the membrane ends also swell. The new seal therefore solves the problem of providing a plate dialyzer in which the seal takes no tools and no space to complete.

Basically, it does not matter for the solution of the task, whether the new plate dialyzer is operated in DC, counter or cross-flow.

When assembling the new dialyzer, it follows that, in an advantageous application, the end face of all the plates which adjoin the channels are enclosed by membranes, so that no parting line between plates and membranes adjoins the channels. This is achieved simply by the fact that each plate and a membrane as a prefabricated unit in a conventional manner congruent stacked one above the other, that on the one hand the covered by the membranes front and on the other hand, the covered by the membrane ends at the end backs of the plates are immittelbar to each other ,

It is advantageous if both for guiding the dialysis fluid flowing between adjacent membranes, such as for guiding the dialysis fluid flowing between the membranes and the plates, the profile of the plate front sides is formed by parallel grooves extending from an anteroom to the antechamber arranged at the opposite end of the plate extend. Hiebei the grooves can be both straight and curved arcuate. You can also cross each other diagonally or at right angles. In the latter case, there are no continuous ribs between the grooves on the plates, but separate cusps. With congruent arrangement of adjacent groove fields of the plates, arise capillary paths of approximately flat-oval cross-section.

If a wide, continuous blood film is to be generated between two plates, respectively

No. 293343 advantageously offset the grooves of superimposed plate front sides against each other and support the plates on marginal sealing shoulders from each other.

The thus formed wide, uninterrupted blood film or the corresponding dialysis fluid, if the dialyzer according to the invention is not used for blood dialysis, is passed both on its upper side as on its underside between available for the mass transfer membrane surfaces. This considerably increases the efficiency of the dialyzer. Appropriately, the other dialysis fluid, in the case of hemodialysis, the rinsing solution, initiated by parallel to the vestibules at the edge of the plate ends in the plate front side molded transverse channels, these transverse channels are connected to the grooves and open laterally into vertical channels. Advantageously, the transverse channels change immediately in front of the sealing shoulders of the plate front sides on the plate backs and the channels are passed through the sealing shoulders and membrane.

To seal the vertical channels on the backs of the plates, the clamped membrane ends are advantageously led away inwards to above the vertical channels.

Such a plate dialyzer preferably operates on the principle of direct current or countercurrent; it has the advantage that it can be assembled from only a few parts. If the operation of the dialyzer according to the cross-flow principle is preferred, only the transverse channels need to be laid on the broad sides of the plates and intersecting grooves for connecting the transverse channels and for connecting the antechambers to the plates are arranged. This advantage results from the fact that the stack of plates and membranes is covered on top and bottom with cover plates and at the end faces with terminal plates and the cover plates and the terminal plates are firmly connected.

Advantageously, the vertical, lateral channels end in aligned sockets of the cover plates.

It is advantageous if the plates are chamfered on their longitudinal sides, so that the membranes on the staple longitudinal sides over the sealing shoulders protrude a little outwards.

The invention will be explained in more detail below with reference to the drawings in a preferred embodiment. This relates to a dialyzer for the blood washing, which can operate on both the DC and the countercurrent principle. The drawings show: Fig.l part of the plate-membrane stack, Figure 2 shows an enlarged section of the plate-membrane stack, Figure 3 shows an enlarged section of the plate-membrane stack, partially broken, Figure 4 is an outside view of the invention 5 shows a section through the longitudinal side wall and the adjacent plates and membrane of the dialyzer according to the invention, FIG. 6 shows a horizontal section through the dialyzer, 7 shows a detail of a vertical section through the dialyzer.

It can be seen in Fig.l the example of four superimposed plates -1- with the associated membranes -3- the structure of the plate-membrane stack of a plate dialyzer according to the invention. The plates -1- are made of plastic, while the membrane -3- are usually made of a cellophane film. The plates -1- have a ribbed top -7-, are formed by the lines for guiding the dialysis fluids. The back -8- of the plates -1- is smooth. The membranes -3- are made the same width as the plates -1- and cover their entire top -7-. However, they are longer than the plates -1- and the end herumgefuhrt around the ends -2-, so that they rest on the edge also on the back -8- of the plates -1-.

One plate -1- and one membrane -3- are combined to form a unit, a plurality of which are joined together to form a plate-membrane stack. The plates -1- are stacked so congruent to each other that each of the front -7- and the backs -8- of the plates -1- lie directly on top of each other. As a result, the diaphragm -3- covering the front sides -7- of the plates -1- directly adjoin one another, and the diaphragm ends -4- which are wrapped around the plate ends -2- are likewise congruent one above the other and are clamped between the plate rear sides -8-. For easier installation, the membrane -3- can be attached to the plates -1- with adhesive.

The drawings do not properly reflect the relationships between membranes and plates, due to a clear presentation. The ratio of the membrane thickness to the plate thickness is about 1: 100, it is therefore not essential that the membrane ends -4- be inserted into special recesses on the Plattenrückseiten -8-. It is important that the membrane ends

-4No.293343 -4- are firmly wedged between the backs -8-, which is still favored by a swelling of the membrane -3- when moistening.

The blood is guided between two membranes -3-. These bulge hiebei in the profiling of the Plattenvorderseiten -7-, which can be advantageously favored by suppression of the directly in the profiling rinsing solution. The blood is introduced via antechambers -10- at the Plattenstirnseiten -6- between the membrane -3-, this is illustrated in Fig.2.

3 shows the internal structure of the plate-membrane stack. It can be seen that the vestibule -10- is formed by a bevelled edge -9- between the end faces -6- and the front sides --7- of the plates -1-. The beveled edge -9- runs in the same width as the profiling, which is formed by grooves -11- in the Plattenvorderseiten -7-. The grooves -11 - are preferably designed trapezoidal and arranged parallel to each other. They run out on both sides of the plates -1- in the vestibule -10-. However, they are not in immittelbarer connection with this, since the antechamber -10- is bounded on all sides by membranes -3-. Parallel to the grooves -11- is on both sides of the plates -1- each provided a sealing shoulder -12-, via which a sealing of the liquid paths to the longitudinal sides of the dialyzer out.

In addition, two immediately adjacent plates -1- rely on the sealing shoulders -12- from, especially if the grooves -11-- adjacent plates are offset from each other. Therefore, the crests of two superimposed plates -1 between the grooves do not stand on top of each other. This has the advantage that the flow path between the membranes -3- is not divided into a plurality of individual channels, but allows the formation of a wide, eroded blood film. This has an advantageous effect on a laminar blood flow.

Shortly before the leakage of the grooves -11- in the antechambers -10- is formed at both respective ends of each dialyzer plate -1- a transverse channel -13-, which serves to supply the rinse solution, which is guided directly into the grooves -11- and with all grooves -11- is therefore connected. Laterally change the transverse channels -13- immediately in front of the sealing shoulders -12- from the front of the plate on the back of the plate and open there in vertical channels -14--. The membrane -3- are on the backs -8- of the plates -1- out over the channels -14 - away inwards, so that by this seal of the

Channels -14 - no liquid can penetrate between the plate backs -8-. Since all

Plates -1- aligned, are formed by these vertical channels -14- at each corner of the plate-membrane stack vertically through these passing channels by the membrane, for example, after being pierced with a tool.

In this embodiment, the grooves -11- of the plate dialyzer perform a dual function. Once you direct the rinsing liquid, which is guided in the through the membrane -3- covered grooves. At the same time they also form the flow path for the blood between the membranes -3- by these under the pressure of the blood bulge in the grooves -11-, so that in this embodiment, the blood and the rinsing liquid are guided parallel to each other, which in the DC or countercurrent is possible.

The seal between the groove spaces and the membrane interstices takes place essentially by pressing the membrane ends -4- on the backs -8- of the plates -1-. The rinsing solution has no opportunity to penetrate into the bloodstreams of the dialyzer by the complete coverage of the beveled edges -9- and the end faces -6- of the plates -1-. On the other hand, it is not possible for the blood to squeeze into the gap between the membrian ends.

4 shows a dialyzer, which is equipped with the above-described plate-membrane stack. The plate-membrane stack is completed on top and bottom with one pressure plate -15- and is covered at its two end faces, each with a connection plate -18-. The cover plates -15- are provided with corner sockets -16-, which are aligned with the vertical channels -14- (Fig.l) in the plate stack. Usually only one socket 16 is needed on the top and on the bottom of the stack, so that the other sockets are closed in the cover plates -15-. This can be done with plugs that fit tightly into the sockets -16-. To produce a vertical channel, the membranes -3-, which are not originally provided with corresponding holes, must be pierced. This can, as already stated, be done by means of a suitable tool. Conveniently, the two sockets -16-, on

- 5 —

No. 293343 of the top and on the underside of the plate dialyzer are put into operation, diagonally associated with each other, so that all passing through the plate dialysis current strands of the introduced through the sockets -16- or derived rinsing liquids are the same length; If the flow rate of the rinsing liquid is to be increased and also for the purpose of uniform pressure distribution in the rinsing liquid system, in particular if the rinsing liquid is sucked through the dialyzer with negative pressure, two jacks 16 can also be operated on diagonally opposite edges of the stack. The cover plates -15- also have ribs -17-, which are mounted for stiffening.

The long sides of the new plate dialyzer are potted with potting compound -22-. For this purpose, the plates -1- be chamfered on their longitudinal sides -21- so that they jump back to the membranes -3- something. Therefore, the membrane -3- on the long sides of the dialyzer are slightly outward. The potting compound therefore encloses the protruding ends of the diaphragm -3-, as particularly clearly illustrated in FIG. The sealing compound -22- thus ensures a firm bond of all components of the dialyzer by connecting the plates -1-, the diaphragm -3-, the cover plates -15- and the terminal plates -18- together and holds together. Further, by welding or gluing the cover plates -15- and the terminal plates -18- are firmly connected.

Fig. 6 illustrates how through recesses -20- in the terminal plates -18- the channels -5- upstream of the plate-membrane stack are formed. The connecting pieces -19- lead into the channels -5-; these can have a tapering cross-section from the mouth of the connection piece 19 to achieve the most uniform distribution of the flow filaments. Basically, an approximately semicircular recess -20-, which connects the nozzle -19- starting in the vertical direction all the antechambers -10- of the plate stack with each other, would be sufficient. The two connecting pieces -19- at the front-side connecting plates -18- are also diagonally offset against each other so that all the current strands of the passing through the connecting piece -19- blood, or in the event that the dialyzer is not used as an artificial kidney, the corresponding dialysis fluid, from a connecting piece -19- to the other are largely the same length. The grooves -11- shown in Fig. 6 are of course not reproduced to scale, but shown enlarged with respect to a clear representation.

FIG. 7 shows, in a sectional view of the dialyzer, how the vestibules -10- open in a wedge shape against the channels -5-. Thus, a slight, unhindered inflow of blood between the membrane -3- is possible. The cross-sections of the channels -5- and the vestibules -10- can be kept so low that they have no appreciable influence on the Blutfüllvolumen the plate dialyzer. Of course, in practice, the transverse channels -13- are arranged as far as possible to the end faces of the plates -1-, in order to wash the membrane -3- with washing liquid on the longest possible path.

The construction of the new plate dialyzer is extremely simple. It consists essentially of three basic elements, namely the plate-membrane units, the cover plates and the connection plates. The assembly of these parts is very simple, in particular, since the new arrangement of the membrane allows effective sealing of the dialysis liquid webs with very simple tools. By this means there is the possibility of a very cheap mass production of such plate dialyzers, whereby this device can be given at the same time in the hands of many patients, especially when used as an artificial kidney.