Methods for optimizing the utilization of filter modules

Abstract

The invention relates to a method for the optimized operation of a number of filter modules connected in series or parallel, comprising the steps of filtering a medium through a first filter module of the filter modules connected in series, conveying the filtrate or retentate to a downstream second filter module of the filter modules connected in series or parallel, and filtering the filtrate through the downstream filter module, wherein, upon reaching a predetermined operating time or a predetermined failure behavior of a filter module, the filter modules are replaced, with one filter module being discarded and the others being replaced by another filter module of the series.

Description

Field of invention

[0001] The invention relates to a method for optimizing the utilization of filter modules and a filter module for the application of this method. State of the art

[0002] Filter modules are used for various purposes; for example, there are filter modules for dialysis or large filters used in industrial water purification. The basic design of these filters is similar, differing mainly in the filter membranes used.

[0003] Especially in dialysis, ultrapure fluid is required for hemodiafiltration as a replacement fluid for the purified blood that is added to the bloodstream before or after dialysis. To produce this ultrapure fluid, two or more filter modules with identical or very similar properties are operated in series, so that the inlet of the subsequent filter is connected to the filtrate outlet of the preceding filter.

[0004] After a predetermined period of use, the filter modules are heavily stressed by both the filtration and disinfection processes. The formation of filter cakes of varying thickness leads to altered filter permeability, while filters subjected to uneven chemical or physical stress develop undesirable changes in their sieving coefficients or retention capacity. Therefore, the filters must be replaced after a certain period.

[0005] Similarly, due to the pressure profile during filtration with tangential or dead-end flow and the resulting longitudinal position-dependent filtration flow in a hollow fiber, the inlet areas of the filters are subjected to greater stress by both the filtration process and the disinfection process than the retentate or dead-end area.

[0006] This varying stress can result in uneven filtration behavior of the individual filter modules over time. For example, the formation of filter cakes of varying thickness leads to altered filter permeability, while filters subjected to uneven chemical or physical stress develop undesirable changes in sieve coefficients or retention rates relative to each other. Description of the invention

[0007] The object of the invention is therefore to improve the utilization of the individual filter modules.

[0008] The invention relates to a method for the optimized operation of a number of filter modules connected in series or parallel, comprising the steps of filtering a medium through a first filter module of the filter modules connected in series, conveying the filtrate or retentate to a downstream second filter module of the filter modules connected in series or parallel, and filtering the filtrate through the downstream filter module, wherein, upon reaching a predetermined operating time or a predetermined failure behavior of a filter module, the filter modules are replaced, with one filter module being discarded and the others being replaced by another filter module of the series.

[0009] To extend filter lifespan—that is, the time until changes lead to undesirable filtering or retention behavior, or an undesirable change in the overall system's performance—regular filter cycling from the outlet to the inlet side is proposed. The first filter is discarded, each subsequent filter is moved forward one position in the opposite direction of flow, and the resulting vacant space at the outlet is filled with a fresh filter. This can be done manually or automatically using appropriate valves. The method is applicable to inside-out and outside-in filtration, as well as to tangential and dead-end filtration, and also to using the filtrate or retentate side of the preceding filter as feed for the subsequent filter, or combinations thereof.Specifically, a method for the optimized operation of a series-connected number of filter modules comprises the following steps: filtering a medium through the first filter module of the series, conveying the filtrate from the first filter module to a downstream second (adjacent) filter module of the series, and filtering the medium through the downstream filter module. Upon reaching a predetermined operating time or a predetermined failure behavior of the first filter module, the last filter module in the series is replaced by a new one, and the replaced filter module replaces the preceding one in the series, and the first filter module is removed from the filtration system. This continuous switching ensures a more even load on the filter modules and stabilizes the performance and characteristics of the filters over the operating period.The existing and defined application period of the filters (replacement interval) can also remain in place.

[0010] Preferably, after the filtrate has passed through the second downstream filter module, it is conveyed to a third downstream filter module, and the process is repeated, if necessary, up to a final filter module. This ensures optimal utilization of the filter modules even with a large number of purification stages.

[0011] Another method for the optimized operation of a parallel-connected number of filter modules comprises the steps of filtering a medium through a first filter module of the parallel-connected filter modules, conveying the retentate of the first filter module and preferably additional medium to a downstream second filter module of the parallel-connected filter modules, and filtering the retentate of the first filter module through the downstream filter module. Upon reaching a predetermined operating time or a predetermined failure behavior of the last filter module, the first filter module in the series is replaced by a new filter module, the replaced filter module replaces the next one in the series, and the last filter module is removed from the filter system. This method also achieves better utilization of all filter modules used.

[0012] Another method according to the invention for the optimized operation of a tangential or dead-end flow filter module comprises the steps of filtering a medium in the tangential or dead-end flow filter module, which has a first and a second end. The medium to be filtered is introduced into the filter at the first end, and the filtrate is discharged from the filter at the second end, or the dead end is located there. Upon reaching a predetermined runtime or a predetermined fault behavior of the filter module, the filter module is rotated so that the first and second ends of the filter module are interchanged, or the filter module inputs are reversed. To achieve a more uniform load or utilization of the membrane in the longitudinal direction, a one-time or regular alternation of the inlet and retentate or dead-end region is proposed.This can be done by manually rotating the filter or automatically using appropriate valves. The alternating stress over a longer period maintains the desired performance and characteristics of the filter, and both sides of the filter module are evenly loaded and unloaded.

[0013] Another method according to the invention relates to the operation of a dialysis machine which provides two different filtrate solutions. Exactly two filter modules are connected in series, wherein the first filtrate is used to produce a dialysate comprising water and electrolytes, and wherein the first filtrate is further used to provide the feed water for the second filter module, and furthermore, the second filtrate is used to produce a substitution solution comprising water and electrolytes to be infiltrated into the blood of a dialysis patient. The method further comprises the following steps: - Filtering a medium through the first filter module of the filter modules connected in series; - Conveying the filtrate from the first filter module to a dialysate preparation unit and to a downstream second filter module of the series-connected filter modules; and - Filtering the filtrate through the downstream filter module and conveying the downstream filtrate to a substitute manufacturing device; characterized by the fact that Upon reaching a predetermined runtime or a predetermined fault behavior of the first filter module, the second filter module is replaced by a new filter module, and the second filter module replaces the first filter module, and the first filter module is removed from the filter system.

[0014] This method enables optimal filter utilization in the dialysate and substitution unit of a dialysis machine suitable for hemodiafiltration. Hemodiafiltration involves the removal of a greater amount of water than the desired ultrafiltrate volume during the flow of patient blood. This excess water must then be diluted with a substitution solution before or after the blood passes through the dialyzer. This method achieves a particularly high removal rate of high-molecular-weight uremic toxins, and the method according to the invention enables particularly cost-effective and resource-optimized operation of hemodialysis. Brief description of the characters Fig. Figure 1 shows a schematic arrangement of n filter modules connected in series; Fig. 2 shows an application of a filter arrangement in which the method according to the invention is applicable; Fig. Figure 3 shows a series of filter modules where the feed / retentate ports are connected in series; Fig. Figure 4a schematically shows a tangential or dead-end flow filter module (inside-out filtration) during a filter module rotation; Fig. Figure 4b schematically shows a tangential or dead-end flow filter module (outside-in filtration) during a filter module rotation; Fig. Figure 4c schematically shows a tangential or dead-end flow filter module (inside-out filtration) with a port swap; and Fig. Figure 4c schematically shows a tangential or dead-end flow filter module (outside-in filtration) with a connection swap. Description of preferred embodiments

[0015] Fig. Figure 1 shows a schematic arrangement of 100 of n filter modules connected in series.

[0016] A filter module 10 has a cylindrical main body 11 with a cap 32, 34 at each end. Feed, filtrate, and retentate connections 12, 14, 16 are provided in the caps 32, 34 and are connected to the corresponding connections in a connection device. The feed connections 12, 12-n, the retentate connections 14, 14-n, and the filtrate connections 16, 16-n are separated within the filter module 10 and connected only via the filter membrane, so that the retentate is filtered and thus becomes filtrate. This occurs, for example, via hollow fiber membranes arranged along the cylindrical body 11. Fig. The filters 10, 10-2, 10-n shown in Figure 1 each have one feed port, one retentate output 14 and two filtrate outputs 16, but the number of different ports can be adjusted as needed.

[0017] The filter modules are connected in series, so that the fluid to be filtered is introduced into a first filter module 10 via the feed port 12 and filtered there. The retentate is conveyed from filter module 10 via a retentate outlet 14 and the filtrate from a filtrate outlet 16. The filtrate outlet 16 is then connected to a feed port 12-2 of a subsequent filter module, so that the already filtered filtrate is filtered a second time through the second filter module 10-2. This process can then be repeated as many times as desired, so that N filter modules can be used. The retentate is in the Fig. In the embodiment shown in 1, the air is discharged from the filter modules.

[0018] After a predetermined usage period, or if the first filter module 10 in the series exhibits a predetermined fault behavior, which can be detected, for example, by measuring certain parameters, filter modules 10 to 10-n are replaced. For this purpose, the first filter module 10 is removed and disposed of, and the downstream filter module 10-2 is inserted as the new first filter module. If there are further filter modules, the third filter module is then used as the new second, and so on, until the nth filter module replaces the (n-1)th filter module, and a new filter module replaces the last filter module 10-n.

[0019] In Fig. Figure 2 describes an application of the above-described procedure for a dialyzer. The first filtration of the fluid to be filtered is carried out, and the filtrate is pumped from the filtrate outlet to the second filter 10-2. There, the fluid is filtered a second time, resulting in the ultrapure fluid. This can then be administered to the patient as a replacement fluid to replace the fluid removed from the blood during dialysis. This is indicated by the two arrows 18 in Fig. Figure 2 shows that the ultrafiltrate that is not removed is fed into the retentate line downstream of the dialysis device. The retentate from the second filter module can then be used for dialysis.

[0020] In Fig. Figure 3 shows another filter module arrangement 100 in which the filter modules are arranged in parallel. Parallel here means that the filtrate from all filter modules 10 to 10-n is discharged without further filtration. In this embodiment, the retentate is passed on to the adjacent filter module 10-2, where it is filtered again. If desired, additional medium can be added to the retentate from the preceding filter module 10 and fed into the adjacent filter module 10-2. Here too, any number N of filter modules can be arranged in parallel.

[0021] If the last filter module 10-n exhibits a predetermined fault behavior, which can be detected, for example, by measuring certain parameters, filter modules 10 to 10-n are replaced. For this purpose, the first filter module 10 is replaced with a new one, and the second filter module 10-2 is replaced with the first filter module 10, up to the last filter module 10-n, which is then disposed of.

[0022] Fig. Figure 4a shows a method for the uniform loading of a tangential or dead-end flow filter module 10. In such a filter module, the inlet side 1 is subjected to significantly higher stress than the other side 2. The in Fig. The filter module 10 shown in Figure 4a is used for inside-out filtration and has a feed port 12, a filtrate port 16, and a retentate port 14, or dead end. After a predetermined usage time, or if the filter module 10 exhibits a fault, which can be detected, for example, by measuring certain parameters, the filter module 10 is removed, reversed, and reconnected so that the initially more heavily used end 1 is now on the dead end side. The initially less heavily used end 2 is then on the inlet side and is subjected to more stress from the moment the filter module 10 is reoriented. This filter rotation improves the utilization of the filter modules.

[0023] Fig. Figure 4b also shows a method for the uniform loading of a tangential or dead-end flow filter module 10. The in Fig. The filter module 10 shown in Figure 4b is used for outside-in filtration and also has a feed port 12, a filtrate port 16, and a retentate port 14, or dead end. After a predetermined usage time, or if the filter module 10 exhibits a fault behavior that can be detected, for example, by measuring certain parameters, the filter module 10 is removed, reversed, and reconnected so that the initially more heavily stressed end 1 is now on the dead end side. The initially less stressed end 2 is then on the inlet side and is subjected to more stress from the moment the filter module 10 is reoriented.

[0024] Fig. Figure 4c also shows a method for the uniform loading of a tangential or dead-end flow filter module 10. This is shown in Fig. The filter module 10 shown in Figure 4c is used for inside-out filtration and has a feed port 12, a filtrate port 16, and a retentate port 14 (or dead end). After a predetermined operating time, or if the filter module 10 exhibits a fault, which can be detected, for example, by measuring certain parameters, the ports of the filter module 10 are reversed. This means that the original retentate or closed dead-end port 14 is connected to the feed, and the original feed port 12 is used as the dead end or retentate port. Similarly, the filtrate port 16 is reversed. This port reversal ensures that the filter module 10 is subjected to a more even load.

[0025] Fig. Figure 4d shows the method for uniformly loading a tangential or dead-end flow filter module 10. Fig. 4c, where the filter module is used for outside-in filtration. The in Fig.The filter module 10 shown in Figure 4d has a feed port 12, a filtrate port 16, and a retentate port 14 (or dead end). After a predetermined operating time, or if the filter module 10 exhibits a fault, which can be detected, for example, by measuring certain parameters, the ports of the filter module 10 are reversed. This means that the original retentate or closed dead end port 14 is connected to the feed, and the original feed port 12 is used as a dead end or retentate port. The filtrate port 16 is also reversed. Reference symbol list 1 original entry page 2 original dead ends 10 Filter module 10-2 Filter module 10-n filter module 11 cylindrical main bodies 12 Feed connection 12-2 Feed connection 12-n feed port 14 Retentate connection 14-2 Retentate connection 14-n Retentate connection 16 Filtrate connection 16-2 Filtrate connection 16-n filtrate connection 18 Replacement fluid connection 100 filter module arrangement

Claims

Method for the optimized operation of a series-connected number of filter modules (10, 10-2, 10-n), comprising the steps of: - filtering a medium through a first filter module of the series-connected filter modules (10, 10-2, 10-n); - conveying the filtrate of the first filter module (10) to a downstream second filter module (10-2) of the series-connected filter modules; and - filtering the filtrate through the downstream filter module (10-2); characterized in that, upon reaching a predetermined operating time or a predetermined fault behavior of the first filter module (10), the last filter module (10-2) in the series is replaced by a new filter module, and the replaced filter module (10-2) replaces the preceding one in the series, and the first filter module (10) is removed from the filter system. Method according to claim 1, wherein after the step of conveying through the second downstream filter module (10-2) the filtrate is conveyed further to a downstream filter module (10-n) and the process is optionally repeated up to a final filter module (10-n). Method for the optimized operation of a parallel-connected number of filter modules (10, 10-2, 10-n), comprising the steps of: - filtering a medium through a first filter module of the parallel-connected filter modules (10, 10-2, 10-n); - conveying the retentate of the first filter module (10) and preferably additional medium to a downstream second filter module (10-2) of the parallel-connected filter modules; and - filtering the retentate of the first filter module (10) through the downstream filter module (10-2); characterized in that, upon reaching a predetermined runtime or a predetermined fault behavior of the last filter module (10-2), the first filter module (10) in the series is replaced by a new filter module, and the replaced filter module replaces the next one in the series, and the last filter module is removed from the filter system. Method for the optimized operation of a tangential or dead-end flow filter module comprising the steps of: filtering a medium in the tangential or dead-end flow filter module (10) having a first (1) and a second end (2), wherein the medium to be filtered is introduced into the filter (10) at the first end (1) of the filter module (10) and the filtrate is discharged from the filter (10) or the dead-end is located at the second end (2); characterized in that, upon reaching a predetermined runtime or a predetermined fault behavior of the filter module (10), the filter module (10) is rotated so that the first (1) and the second (2) end of the filter module (10) are interchanged, or the filter module inputs are reversed.

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