EP4096738A1

EP4096738A1 - Device and method for producing dialysate

Info

Publication number: EP4096738A1
Application number: EP21703380.2A
Authority: EP
Inventors: Stefan Konrad MARTERSTOCK; Torsten Keller; Benedict GLASER
Original assignee: Fresenius Medical Care Deutschland GmbH
Current assignee: Fresenius Medical Care Deutschland GmbH
Priority date: 2020-01-28
Filing date: 2021-01-26
Publication date: 2022-12-07
Also published as: CN115038473A; EP4096737A1; WO2021151875A1; US20230146806A1; WO2021151874A1; CN115023248A; US20230103623A1

Abstract

The invention relates to a device and a method for producing dialysate, the device having a first part and a second part in the form of a circuit, wherein: the first part comprises a water connection, or a water container and the primary side of a filter, the filter being designed to produce purified water, from the water, by forward osmosis; and the second part comprises the secondary side of the filter, a reservoir, a filtrate line, which runs from the secondary side of the filter to the reservoir, and a return line running from the reservoir to the secondary side of the filter; and in addition, an electrodialysis unit comprising a diluate chamber and a concentrate chamber is provided, the concentrate chamber being fluidically connected to the secondary side of the filter.

Description

Device and method for the production of dialysate

The present invention relates to an apparatus and a method for the produc- tion of dialysate.

From the prior art it is known to supply dialysis machines with ready-to-use dialysate, ie with a ready-to-use dialysis solution, for example from a line system which is connected to a central device for producing the dialyzate and which is generally designed, a plurality of To supply dialysis machines with dialysate.

Furthermore, it is known from the prior art to produce the dialysate on the dialysis device itself, ie in a decentralized manner. For this purpose, an RO system (RO = reverse osmosis) can be provided for the production of ultrapure water, which is part of the dialysis machine or can be designed as a separate unit. The ultrapure water is mixed in the dialysis machine with one or more concentrates in order to keep a ready-to-use dialysate for treating the patient. In the production of ultrapure water using the RO process, there is a The disadvantage is that the process requires high pressures in the range from 6 to 15 bar, which is correspondingly energy-intensive.

The present invention is based on the object of providing a device and a method by means of which an energy-efficient dialysate production is possible.

This object is achieved by a device with the features of claim 1 and by a method with the features of claim 15.

It is then provided that the device has a first part and a second part designed as a circuit, the first part comprising a water connection or a water container and the primary side of a filter, the filter being designed to pass purified water through Establish forward osmosis, and wherein the second part comprises the secondary side of the filter, a reservoir, a filtrate line which leads from the secondary side of the filter to the reservoir, and a return line leading from the reservoir to the secondary side of the filter, further comprising a Electrodialysis unit is provided with a diluate chamber and with a concentrate chamber, the concentrate chamber being in fluid communication with the secondary side of the filter.

The combination with the electrodialysis provided according to the invention to increase the (volumetric) concentration of the freely moving electrolytes by applying an electric field leads to an increased concentration of the electrolyte on the filter and thus to an increase in the osmotic pressure.

It is preferably provided that raw water or tap water is obtained from the water tank or from the water connection. The reservoir can contain one or more concentrates from which a dialysate can be produced by dilution or dissolution in permeate.

In the context of the present invention, the term “dialysate” encompasses both a ready-to-use dialysis solution and one or more components of this.

The present invention is thus based on the idea of using the different electrolyte concentrations between raw water and dialysate / concentrate and the associated osmotic pressure in order to produce dialysate with the aid of a suitable forward osmosis membrane of the filter. The forward osmosis is also called FO for short in the following. The electrodialysis unit, the concentrate chamber (s) of which is / are in fluid connection with the secondary side of the filter, is used to increase the osmolarity on the filtrate side of the filter.

For the production of dialysate, the permeate is mixed with one or more concentrates after production until a physiological or the desired electrolyte concentration is reached. At least one of the concentrates is preferably located in the reservoir. It is conceivable that at least one concentrate (or all concentrates) is fed to the second part of the device via a concentrate line.

The substance concentration of electrolytes (and thus the conductivity as a sum parameter for the electrolyte concentration) is significantly higher in dialysate or in dialysate concentrate than in tap water. The electrical conductivity of drinking water (according to the German Drinking Water Ordinance) is a maximum of 2.79 mS / cm, the electrical conductivity of dialysate is usually 12 to 16 mS / cm. This difference (which does not limit the invention) in the electrolyte concentration leads to an osmotic pressure gradient which, according to the invention, is used for the process of dialysis sat production is exploited by FO. The electrodialysis unit increases the osmolarity on the secondary side of the membrane.

The water, which is preferably tap water, is preferably warmed to generate dialysate or concentrate (preferably to 37 ° C.). If this happens right at the beginning of the process, the efficiency of the FO process improves, since the osmotic pressure gradient is directly dependent on temperature.

An essential part of the invention is the use of forward osmosis for the preparation of dialysate. This treatment can be done by using used dialysate or raw water. The use of raw water, e.g. from the house supply, is preferred. The FO membrane is therefore preferably also a sterile barrier, so that good home dialysis is possible for both HD (hemodialysis) and PD (peritoneal dialysis) from concentrates (dry, liquid, etc.).

The concentrate or the dialysate is preferably circulated on the secondary side until the desired final concentration, conductivity, etc. is reached.

The second part of the device is a circuit. In a preferred embodiment of the invention, the first part of the device is also designed as a circuit, i.e. the water is circulated on the primary side of the filter and the dialysate or dialysate concentrate is circulated past the secondary side of the filter. The electrodialysis unit is part of the circuit.

The diluate chamber of the electrodialysis unit is preferably in fluid connection with the reservoir. It is also conceivable if a conductivity measuring cell or a concentration measuring cell is arranged upstream of the diluate chamber in the flow direction of the dialysate. In the context of the invention, this is to be understood as any measuring devices by means of which conclusions can be drawn about the conductivity and / or concentration.

It is conceivable if a pump is arranged between the conductivity measuring cell or the concentration measuring cell and the electrodialysis unit.

In a further embodiment of the invention, a conductivity measuring cell or a concentration measuring cell is arranged in the flow direction of the dialyzate after the diluate chamber.

The conductivity measuring cell or the concentration measuring cell can be arranged between the diluate chamber and the reservoir.

It is also conceivable that the conductivity measuring cell or the concentration measuring cell is arranged between the reservoir and the filter. It is conceivable that a pump is arranged between the conductivity measuring cell or the concentration measuring cell and the filter. The pump can also be arranged elsewhere in the secondary circuit, for example also in front of the conductivity measuring cell or concentration measuring cell.

In a further embodiment of the invention, a line section is provided which leads from the concentrate chamber to the return line, which in turn leads from the reservoir to the secondary side of the filter 4.

A dialysate concentrate can be located in the reservoir, which is preferably designed as a bag or other container. A plurality of reservoirs can be provided and a valve arrangement can be provided which is designed to switch the plurality of reservoirs alternately in fluid connection with the second part of the device.

A bicarbonate concentrate and / or an acidic concentrate, which is designed for the production of dialysate, can be present in the reservoir.

It is also conceivable if several compartments are provided in the reservoir, in each of which one or more concentrates are present.

The concentrate can be present in the reservoir as powder, granules, slurry or in liquid form.

The concentrate can also be fed in via separate lines.

The present invention also relates to a method for producing dialysate with a device according to one of claims 1 to 14, wherein the primary side of the filter is supplied with water, that the permeate is supplied to the secondary side by forward osmosis and that the secondary side of the filter a dialysate concentrate is fed from the reservoir and / or from another source and is mixed with the permeate. The dialysate present on the secondary side of the filter is concentrated by means of electrodialysis.

The dialysate or dialysate concentrate can be conveyed on the secondary side of the filter in the circuit until the conductivity and / or a concentration or some other parameter representative of these parameters corresponds to a target value or is in a target value range.

A plurality of reservoirs can be present in the second part of the device, one reservoir being filled with the dialysate or with the dialysate concentrate and the other reservoir being emptied for use in a dialysis machine. Furthermore, it is conceivable according to the invention that to further increase the osmotic pressure on the secondary side of the filter, a physiologically compatible substance, in particular glucose, or a substance to be separated before use as dialysate, in particular magnetic nano iron particles, are added.

With a device according to the present invention, for example, one or better two small chambers or reservoirs can be filled with ready-to-use dialysate, so that one chamber is always available for the removal of dialysate. This device is also called a “micro-batch”. But it can also be provided to create a large supply of, for example, 2-5 I (typical for PD) or 70-100 I (typical for HD), for example in a reservoir, in particular a special bag. Such a device or method is also called “macro-batch”.

A FO process uses the osmotic pressure gradient to filter water, preferably tap water. The energy-consuming production of permeate by RO does not take place according to the invention and dialysate or concentrate is produced directly. Since the treatment process preferably takes place immediately before the fluid is used, i.e. there is no pipeline network in between, the effort required to maintain the necessary hygiene is simplified. Constant miniaturization means that new possibilities in terms of portability are also conceivable. In addition, the process is significantly quieter than that of an RO system with the associated pump for generating pressure.

The reservoir is preferably a bag which has partially or entirely flexible walls. A reservoir that has entirely or partially rigid walls, such as a cartridge, is also conceivable and encompassed by the invention. In a preferred embodiment of the invention, the reservoir has connection means for fluidic connection to a dialysis machine. It is preferred that several, preferably two, reservoirs are provided and that there is a valve arrangement which is designed to alternately connect the reservoirs to the second circuit. The reservoir that is not connected to the second circuit can be removed and used for dialysis. At the same time, the other reservoir is filled with the ready-to-use dialysate or concentrate.

The named means of the reservoir can be a connector or a hose or a connection for a hose or other means by which a fluid connection can be established between the interior of the reservoir and a dialysis machine. By means of a connector, the reservoir, which is preferably designed as a bag, can preferably be fixed directly to a counterpart on a dialysis machine. It is also conceivable that the reservoir has a hose or an adapter for a hose, by means of which the ready-to-use dialysate or dialysate concentrate can be used, e.g. in the area of peritoneal dialysis.

The concentrate preferably located in the reservoir can be, for example, a bicarbonate concentrate and / or an acidic concentrate that is designed for the production of dialysate.

The concentrate can be in the reservoir, for example, as a powder, granulate, slurry or in liquid form.

A pump is preferably arranged in the first part and / or in the second part of the device, which is also referred to as the “second circuit”. If the pump is in the first part, the pump can generate a sufficiently high transmembrane pressure to increase the permeate flow on the primary side of the filter. The pump on the secondary side has the advantage that the dialysate or dialysate concentrate can be repeatedly fed past the filter membrane until the desired concentration or conductivity etc. is achieved. In addition, the pump on the secondary side can be used to maintain a high dialysate flow, for example during priming.

In order to detect the end time of the production of the dialysate or the dialysate concentrate, a sensor, preferably a conductivity measuring cell, can be arranged in the second circuit. If this has a measured value that lies in a target value range, the production of the dialysate or dialysate concentrate can be regarded as finished and the reservoir can be removed for use in the dialysis treatment. For example, the reservoir can also be designed to be rigid in terms of volume and the sensor can be filled with a filling level probe. It is also conceivable that a gravimetric end time determination is carried out.

It is conceivable that a concentrate line opens into the second circuit, which in turn is connected to a reservoir for dialysate concentrate, so that a further concentrate can be introduced into the second circuit by means of the concentrate line. This is useful in the event that the reservoir does not contain all of the concentrates required, but only some of them.

The reservoir can have exactly one compartment in which there are one or more concentrates that are dissolved in the context of the present invention by means of the permeate. It is also conceivable that the reservoir has several compartments, in each of which one or more concentrates are present. In this case, it is possible for the compartments to be arranged and designed in such a way that they open in a staggered manner so that certain osmolarities are staggered in time.

The present invention further relates to a method for producing a dialysate with a device according to one of claims 1 to 14, wherein the primary side of the filter water, preferably tap water, is supplied, the permeate is supplied to the secondary side by forward osmosis and wherein the Secondary side of the filter from the reservoir and / or from another Source a dialysate or a dialysate concentrate is supplied, which is mixed with the per meat and that an increase in the concentration of the dialysate on the secondary side is made by electrodialysis.

It is preferably provided that the dialysate or the dialysate concentrate is conveyed on the secondary side in the circuit until the conductivity and / or a concentration or some other parameter correlated therewith corresponds to a target value or is in a target value range.

It is conceivable that if there are several reservoirs, one reservoir in the second circuit is filled with the dialysate or with the dialysate concentrate and the other reservoir is emptied for use in a dialysis machine, i.e. as part of a dialysis treatment.

It is advantageous if, to increase the osmotic pressure on the secondary side of the filter, a physiologically compatible substance, in particular glucose, or a substance to be deposited before use as a dialysis solution, in particular magnetic nano iron particles, is added.

At this point it should be noted that the terms “a” and “an” do not necessarily refer to exactly one of the elements, although this represents a possible embodiment, but can also designate a plurality of the elements. The use of the plural also includes the presence of the element in question in the singular and, conversely, the singular also includes several of the elements in question.

Further details and advantages of the invention will be explained in more detail using an exemplary embodiment shown in the drawing.

Show it: Figure 1: a schematic flow diagram of a device according to the invention in a first embodiment,

FIG. 2: a schematic flow diagram of a device according to the invention in a second embodiment,

FIG. 3: a schematic flow diagram of a device according to the invention in a third embodiment and

Figure 4:. a schematic flow diagram of a device according to the invention in a fourth embodiment.

Figure 1 shows with the reference numeral 1, a heat exchanger running on the raw water supply. The heating of the raw water supplied to the filter 4 increases the effectiveness of the osmosis process. The raw water inlet chamber, which has a ventilation and / or a level sensor, is identified by the reference numeral 2.

As can be seen from FIG. 1, the device comprises a first part in the form of the raw water circuit and a second part in the form of the mixing circuit.

The reference number 3 denotes the circulation pump in the raw water circuit, i.e. in the first circuit according to the invention. The FO filter is identified with 4, 5 designates the conductivity temperature measuring cell for raw water and "back flow" control. The reference number 6 denotes the raw water circulation valve and 7 the flush valve for flushing the filter 4.

The raw water circulation valve 6 can be designed to adjust and / or regulate the transmembrane pressure. If the trans- membrane pressure, the raw water circulation valve is fully or partially opened or closed.

The drain is marked with 8 and an A-concentrate pump (dialysis concentrate / acid concentrate) (A-concentrate can also be added later) and with 10 a B-concentrate pump (dialysis concentrate / bicarbonate concentrate) is marked.

The reference number 17 is a degassing device and 15 is a device for heating the water supplied to the filter 4 on the primary side.

13 identifies the circulation pump in the mixing circuit, i.e. in the second circuit according to the invention. The reference number 14 denotes a concentrate bag which serves as a collecting chamber and can be designed with ventilation and a level sensor (here the filtrate is accumulated). Two parallel collecting chambers, preferably concentrate bags, are preferably provided. But it can also be provided rigid reservoirs. This means that one chamber can always be filled with dialysate and the other chamber can always be emptied or used as part of the dialysis treatment.

Reference 16 is a conductivity-temperature measuring cell for monitoring the dialysate quality and composition (filtrate + bicarbonate mixing ratio or filtrate + bicarbonate + acid concentrate - mixing ratio). Alternatively, a second measuring cell can be used to readjust the B concentrate. The measuring cell 16 is arranged upstream of the pump 13.

A heat exchanger 1, which is arranged upstream of the filter 4, is provided for heating the raw water. The heat exchanger is flowed through on the one hand by raw water to be heated and on the other hand by the dialysate present on the secondary side, which heats the raw water in the heat exchanger 1. The heat exchanger can alternatively also between the flush valve 7 and the drain 8, so that the heat of the water that is fed to the drain can be transferred to the raw water to be heated.

The pump 13 conveys the dialysate into the electrodialysis unit 18, which has at least one anion and at least one cation exchanger membrane between two electrodes. Usually there is a stack of alternating anion and cation exchange membranes. Each pair of ion exchange membranes or a pair of ion exchange membrane and electrode forms a separate chamber. When an electrical direct voltage is applied to the electrodes, salts accumulate in the concentrate chamber or chambers and low-salt solutions are formed in the diluate chamber or chambers.

The pump 13 conveys the dialysate of the secondary circuit into the electrodialyse unit 18, which in the simplified embodiment shown here consists of a central diluate chamber D and two peripheral concentrate chambers K1, K2. From the concentrate chambers K1, K2 the concentrate reaches the secondary side of the filter 4. This is done via a line L1 in which the shut-off valve 19 is located and which opens from the chamber K1, K2 into the return line R, which in turn contains the bag 14 etc. fluidly connects to the secondary side of the filter 4.

The shut-off valve 21 is located downstream of the bag 14.

A line L2, which leads to the bag 14, extends from the diluate chamber D of the electrodialysis unit 18. The shut-off valve 20 is located in this line and, downstream of this, a conductivity measuring cell 22.

The process for producing dialysate or dialysis concentrate is exemplified as follows:

0. (initial preparation) The FO filter 4 is on the raw water side, that is, on the side of the first circuit, filled with raw water (tap water).

The FO filter 4 is filled with physiological solution on the filtrate side or raw water or permeate (= filtrate) is pressed onto the filtrate side by a slight overpressure on the raw water side.

1. Add concentrate to the mixing circuit

Example: Volume in the mixing circuit: 800 ml (400 ml in the filter / 400 ml in the circuit) Addition of concentrate: 11.4 ml A concentrate and 14 ml B concentrate.

2. Addition of permeate to the mixing circuit

Permeate (filtrate) flows through the FO membrane until the correct mixing ratio is established. This is relevant for the osmotic pressure and thus for the permeate flow through the membrane.

Check the mixing ratio (target Na concentration in the dialysate typically 138 mmol / L) by measuring the dialysate conductivity (typically 12 to 16 mS / cm).

3. Removal of the finished dialysate

New cycle starts with the addition of concentrate (1 -> 2 -> 3)

The voltage of the electrodes (anode, cathode) of the electrodialysis unit 18 can be set so that the conductivity measuring cells 22 and 16 each measure the desired conductivities. However, it is also conceivable that during the mixing process of filling the bag 14, the conductivity deviates from the expected value for completely mixed dialysate up to the end.

As part of the production of dialysate, a cycle is started with 9 and / or 10, i.e. concentrate (A and / or B) is added. The concentrate diluted by the filter 4 is repeatedly concentrated by the electrodialysis unit 18 without necessarily maintaining the correct, relative mixing ratio of the electrolytes for dialysate in the return via the valve 19.

At the end of the process, however, the entire volume of the circuit with components 4, 18 and 14 ends up in reservoir 14, which means that all electrolytes from the circuit with components 18, 19 and 4 are pumped into reservoir 14 and the composition is ultimately correct .

In this case, it is particularly advantageous if a conductivity measuring cell for sampling is arranged upstream or downstream of the valve 21, which is arranged downstream of the reservoir 14, and after the reservoir 14, in addition to or instead of the conductivity measuring cell 22 according to FIG. 1 Such an exemplary embodiment is shown in FIG. There, the conductivity measuring cell 22 is arranged between tween the valve 21 and a pump 13, which is in the Rückführungslei device R before the confluence of the line L1 in the return line R angeord net. The pump 24, which is arranged at the position of the pump 13 in FIG. 1, is also present in the secondary circuit.

In the exemplary embodiment according to FIG. 2, a degassing device 25 is arranged upstream of the filter 4 in the raw water circuit, from which a degassing line E, in which a shut-off valve 23 is located, leads to the raw water inlet chamber 2. The degassing has the advantage that no air bubbles can get into the filter 4, so that the effectiveness of the FO process is further increased. Otherwise, with regard to the exemplary embodiment according to FIG. 2, reference is made to the embodiment according to FIG.

Other components are only shown as examples. For example, instead of the 13th pump, a pump between 14th and 21st and another pump between 18th and 19th could be provided.

FIG. 3 shows an exemplary embodiment largely corresponding to FIG. 2, with the difference that the pump 24 upstream of the electrodialysis unit 18 is omitted and the pump 13 downstream of the reservoir 14 in the flow direction not before, as in FIG. 2, but after the confluence of the line L1 into the return line R. is arranged.

FIG. 4 corresponds to the exemplary embodiment according to FIG. 3 with the difference that the heat exchanger 1 for heating the raw water flowing into the container 2 is heated by the fluid that runs out of the container 2 into the outlet 8. As can be seen from FIG. 4, the line running to the heat exchanger 1 can branch off downstream of the flush valve 7, for example.

It should be noted that all components of the exemplary embodiments, with the exception of the core components (4, 14, 18), are optional and are drawn in by way of example in order to illustrate a possible application.

It would also be conceivable to return the used dialysate to chamber 2 in order to carry out reprocessing in accordance with patent DE102018105120 and thus save energy and water.

It is also conceivable to support the FO process in the filter 4 by an additional hydraulic pressure or negative pressure from a pump. The entire process can also be designed as a continuous process with continuous concentrate addition, permeate production and dialysate removal.

In addition, it is possible to install a second collection chamber or reservoir and preferably a bag that is filled alternately with the first chamber. Dialysate can thus be withdrawn from one chamber while the other chamber is being filled. This ensures a quasi-continuous production of dialysate.

The following options for increasing the osmolarity on the product side of the filter 4 should preferably be mentioned:

In order to increase the osmotic gradient between tap water and dialysate and thus the efficiency of the osmosis process, it is possible on the product side, i.e. in the second circuit: a. Add a physiologically compatible additive. Glucose would be a possible substance that is already contained in HD dialysate in concentrations of up to 1 g / l. b. Add a substance that does not remain in the dialysate, but is physically or chemically deposited beforehand (or is retained by the dialyzer). Magnetic nano iron particles would be suitable for this. The particles are added upstream of the filter and deposited after the filter with the aid of a magnetic field.

It would also be conceivable to return the used dialysate to chamber 2 in order to carry out reprocessing and thus save energy and water. It is also conceivable to support the FO process in the filter 4 by an additional hydraulic pressure or negative pressure from a pump.

The following should be mentioned as a supplementary idea: To test the forward osmosis filter 4 in operation to ensure that the retention function is still guaranteed.

With the use of forward osmosis technology in sensitive areas, such as dialysis technology, it becomes necessary to ensure or at least monitor the correct functioning of the FO membrane.

Possible solutions are:

1. Measurement of the resulting osmotic pressure when the FO membrane is functioning correctly. If the membrane is OK, a transmembrane pressure is built up over the FO membrane (the osmotic pressure). The inlets and outlets of the FO filter can be blocked with valves and the osmotic pressure can be measured with a pressure sensor. The filter is filled accordingly beforehand (with concentrate on the secondary side and with e.g. tap water on the primary side). The resulting pressure must then remain constant over a certain period of time, otherwise it can be assumed that a direct mixing of the liquids normally separated by the FO membrane takes place.

2. Priming the FO filter by pressing tap water onto the permeate side and then measuring the conductivity of the permeate.

3. Determination of the inflow and the withdrawn fluid quantities (on the FO filter) as well as their conductivity. The values can then be used to check the plausibility of the dilution using the FO process. 4. Fill the filter on the secondary side with air. Apply liquid on the primary side and measure the pressure from which the filter “breaks through”, ie liquid flows onto the secondary side (so-called bubble point test).

According to the macro-batch approach, the forward osmosis-supported dialysate generation takes place as follows:

The solution is prepared in one or more batches. The batch can, for example, be a bag that contains the concentrates for preparing the solution in solid or liquid form. It is advantageous if the amount of dialysate is sufficient to carry out a dialysis treatment (60L to 250L).

A description of a possible embodiment of the method is as follows:

Primary side

The primary side (“feed” side) of the FO membrane is connected to a raw water source (tap water connection). The pressure of the raw water sources or a separate pressure booster (pump or hydrostatic pressure storage tank) ensure that raw water flows over the primary side. The same pressure source can also be used to initially fill the primary side.

Secondary side / secondary circuit

The secondary side ("product" side) of the FO membrane is connected to the batch, i.e. to the reservoir, preferably to the bag. A separate pressure boosting device (pump or hydrostatic pressure accumulator) ensures that the secondary side of the solution is overflowed.

The solution is preferably repeatedly led along the FO membrane. This means that the batch is connected to the FO filter via a circuit. Priming (filling)

At the beginning only the concentrates are in dry form or slightly diluted in the batch (as powder, granulate, "slurry" or in liquid form). The concentrations are dissolved / diluted with a little solvent (usually tap water). The dilution must be carried out in such a way that the FO membrane used is not damaged by the still greatly increased electrolyte concentration (no crystallization on the membrane or the like). All concentrates can be in the concentrate solution right from the start or added to the batch over time.

If the concentrates are added with a delay, the osmotic pressure gradient can be kept in a range that is optimal for the effectiveness of the FO membrane.

Options for the initial dilution / solution of the concentrates and for priming (filling) the secondary side:

• The filter is pre-filled and / or the batch is sufficiently pre-filled to start the process and fill the secondary side / secondary circuit

• Priming (filling) the secondary side / secondary circuit by generating negative pressure -> the pump on the secondary side sucks in the filtrate and fills the batch bag and the secondary side of the filter (control of the transmembrane pressure by means of a pressure sensor).

• Priming (filling) the secondary side / secondary circuit by overpressure on the primary side -> pressure source primary side presses filtrate and fills the batch bag and the secondary side of the filter (control of the transmembrane pressure by pressure sensor) • Use liquid to prime the filter from the previous filling process as a priming solution

It is possible to initially operate / fill only the filtrate side with minimal i.e. reduced circulation -> reduced secondary volume (suitable, small bag shape, FO filter with reduced secondary volume.

Subsequent addition of water e.g. by volume from FO membrane or by manual addition point on the batch. Objective: lower priming volume

Making the solution

The concentrated solution is passed past the secondary side of the FO membrane. The high osmotic pressure gradient between raw water and solution leads to a sustained flow of filtrate over the FO membrane into the batch. With a closed batch, the osmotic pressure gradient and thus the production of permeate decrease over time. However, a gradient is maintained until an electrolyte concentration that is typical for a physiological solution is reached (electrolyte concentration approx. 0.15 mol / L in the finished dialysate).

Production stop:

• Volume stiff system is filled -> target volume is reached / static pressure increases -> measure pressure or the process comes to a standstill by itself (p_static = p_osmose)

• Shutdown via LF (conductivity) or LF only protection system

• Shutdown via weight determination

• Time-controlled

• Measure TMP (transmembrane pressure) / measure filtrate flow • The process ends as soon as the mixing ratio of A concentrate to permeate is, for example, 1:35 (= mixing ratio for finished concentrate).

• Tank (volume stiff)

Advantages of the present invention are in a preferred embodiment:

• A FO process (especially FO membranes with Auqaporin technology) uses the osmotic pressure gradient to filter tap water. The energy-intensive production of permeate is “left out” and dialysate is produced directly. Nevertheless, comparatively high filtration rates are achieved:

FO filter (e.g. Aquaporin Inside HFF02): 22.60 liters / m ² / hour (25 ° C / 5.8% NaCI solution vs. tap water) RO filter e.g. 50 liters / m ² / hour at 15 bar

• Since the treatment process takes place immediately before the fluid is used, i.e. there is no pipeline network in between, the effort required to maintain the necessary hygiene is simplified. Constant miniaturization means that new possibilities in terms of portability are also conceivable.

• In an FO process, the energy-intensive production of filtrate (permeate) is omitted and a physiological solution (dialysate) is produced directly.

• The production of permeate via an FO membrane, compared to all the processes mentioned, is technically less complex (only one FO membrane instead of several adsorber cartridges, no piping systems (designed for high pressures)) and is therefore suitable for home systems such as they are common in PD dialysis.

• The entire system is space and cost-saving, less complex and easier to clean. • In addition, better filtrate quality is to be expected compared to adsorber technology, since the retention rates of the FO membranes almost approach the retention rates of RO membranes (RO technology currently realizes the maximum retention rate in filtration processes) especially critical PD solutions that are infiltrated directly into a patient's abdomen.

• Dispatch of dry concentrate bags or highly concentrated concentrates instead of the current ready-to-use liquid solutions (lower transport weight, better shelf life and sterility)

• Overall, the technology is suitable for the decentralized, needs-based provision of physiological and hygienic solutions

• The process is significantly quieter than an RO system with an associated pump for generating pressure -> better suited for the home environment.

FIG. 2 shows a device in a schematic view for producing a macro batch:

The reference number 1 shows the water connection, 2 the circulation pump of the mixing circuit, 3 the FO filter, 4 the conductivity-temperature measuring cell for raw water and "back-flow" control (could also be arranged between 5 and 2 in the suction line ), 5 the reservoir, preferably a bag with concentrate) and 22 the drain. As can be seen from Figure 2, in this embodiment, for example, the first part of the device is not designed as a circuit.

The FO filter is preferably disposable / semi-disposable and is replaced as required (fixed interval, according to a certain volume of filtrate, “bubble point test” / “pressure maintenance test fails). The following options / expansion options are to be mentioned:

• Air separation in the circuit to avoid air on the filter

• Pressure increase on the raw water side in order to increase the raw water flow or to superimpose a hydrostatic pressure on the FO process (-> increase of the filtration rate)

• Introduction of a physiologically neutral substance to increase the osmotic pressure

• Introduction of a substance that can be separated in a further step (FO agent) - Subsequent separation of the agent from the product (as is common today), e.g. via a thermal process, filtration or by separation in a magnetic field (when using a ferrofluid as agent).

• Reuse of already used dialysate, by feeding the used dialysate on the primary side / bag emptying -> waste weight and volume lower.

• Used dialysate is reused throughout the entire dialysis session

• Used dialysate is used to start the process (fill the secondary circuit)

• Monitoring of the transmembrane pressure (limit values specific for FO filters) in order to avoid damage to the FO filter (-> important for aquaporin filters)

• FO membrane tests to monitor the integrity of the filter

• Filling / emptying of several bags at the same time.

• Monitoring of the conductivity in the batch, in the suction line before the FO filter or after the FO filter to control the filtrate production process

• Heating and / or heat exchanger in the primary or secondary circuit (preferred) to bring the raw water / filtrate to a temperature that is optimal for the FO process (25 to 50 ° C)

• Additional ultrafilter in the feed line upstream of the FO circuit in order to hold back high levels of microbiological, chemical or physical contamination and thus to reduce “fouling” of the FO filter and to achieve a longer service life • Additional ultrafilter after the FO circuit to hold back any microbiological (endotoxins), chemical or physical contamination that is still present

• Test of the FO filter (e.g. measurement of osmotic pressure) before and after the batch filling in order to ensure the filter effect and thus the validity of the batch. Release of the batch only after a successful test (e.g.)

• In principle, analogous to all the versions described in the context of the micro-batch approach

Possible areas of application of the invention are:

• Prepare FID solution / batch for a treatment e.g. 70L

• Produce PD solution / batch for one treatment or several bags (e.g. 5 L bags)

• Mobile production of NaCI solution (after disasters, emergencies or in the event of poor energy supply)

• Fill the Genius tank with the FO system, manufacture the acute bag

Claims

Device and method for producing dialysate claims

1. Device for the production of dialysate, the device having a first part and a second part designed as a circuit, the first part comprising a water connection or a water container (2) as well as the primary side of a filter (4), the Filter (4) is ausgebil det to produce purified water from the water by forward osmosis, and wherein the second part is the secondary side of the filter (4), a reservoir (14), a filtrate line that leads from the secondary side of the filter (4 ) leads to the reservoir (14), and comprises a return line (R) leading from the reservoir (14) to the secondary side of the filter (4), furthermore an electrodialysis unit (18) with a diluate chamber (D) and with a concentrate chamber (K1, K2) is provided, the concentrate chamber (K1, K2) being in fluid connection with the secondary side of the filter (4).

2. Device according to claim 1, characterized in that the diluate chamber of the electrodialysis unit (18) is in fluid connection with the reservoir (14).

3. Device according to claim 1 or 2, characterized in that a conductivity measuring cell (16) or a concentration measuring cell is arranged upstream of the diluate chamber (D) in the flow direction of the dialysate.

4. Apparatus according to claim 3, characterized in that a pump (13, 24) is arranged between the conductivity measuring cell (16) or the concentration measuring cell and the electrodialysis unit (18).

5. Device according to one of the preceding claims, characterized in that a conductivity measuring cell (22) or a concentration measuring cell is arranged in the flow direction of the dialysate after the diluate chamber (D).

6. Device according to one of the preceding claims, characterized in that a conductivity measuring cell (22) or the concentration measuring cell between the diluate chamber (D) and the reservoir (14) is arranged.

7. Device according to one of the preceding claims, characterized in that the conductivity measuring cell (22) or the concentration measuring cell is arranged between the reservoir (14) and the filter (4).

8. The device according to claim 7, characterized in that a pump (13) is arranged between the conductivity measuring cell (22) or the concentration measuring cell and the filter (4).

9. Device one of the preceding claims, characterized in that a line section (L1) is provided which leads from the concentration chamber to the return line (R).

10. Device according to one of the preceding claims, characterized in that there is dialysate concentrate in the reservoir (14).

11. Device according to one of the preceding claims, characterized in that a plurality of reservoirs (14) are provided and that a valve arrangement is present which is designed to switch the plurality of reservoirs alternately in fluid connection with the second part of the device.

12. Device according to one of the preceding claims, characterized in that a bicarbonate concentrate and / or an acidic concentrate is present in the reservoir (14), which is designed for the production of dialysate.

13. Device according to one of the preceding claims, characterized in that a plurality of compartments are provided in the reservoir (14), in each of which one or more concentrates are present.

14. Device according to one of the preceding claims, characterized in that the concentrate in the reservoir (14) is present as powder, granules, slurry or in liquid form.

15. A method for producing dialysate with a device according to any one of claims 1 to 14, characterized in that the primary side of the filter (4) is supplied with water, that the permeate is supplied to the secondary side by forward osmosis and that the secondary side of the filter (4) from the reservoir (14) and / or from another source a dialysate concentrate is supplied, which is mixed with the permeate and that an increase in the concentration of the dialysate on the secondary side is made by electrodialysis.

16. The method according to claim 15, characterized in that the dialysate or the dialysate concentrate on the secondary side of the filter (4) is circulated until the conductivity and / or a concentration or another parameter representative of these parameters corresponds to a target value or lies in a setpoint range.

17. The method according to claim 15 or 16, characterized in that several reservoirs (14) are present in the second part of the device, one reservoir (14) being filled with the dialysate or with the dialysate concentrate and the other reservoir (14) for use is emptied in a dialysis machine.

18. The method according to any one of claims 15 to 17, characterized in that to increase the osmotic pressure on the secondary side of the filter (4) a physiologically compatible substance, in particular glucose, or a substance to be deposited before use as dialysate, in particular magnetic nano Iron particles are added.