Storage of machines for generation of medical fluid

Abstract

A machine (20) is configured for use in generation of a medical fluid. The machine comprises an inlet connector (21a) for connection to a fluid source, a fluid processing device (25) for processing a first fluid from the fluid source into a second fluid, and an outlet connector (22a) for connection to a receiving device. The fluid processing device comprises a fluid path system (200) and one or more fluid pumps (26a-26c). The machine operates to prepare for storage, in which the machine is inoperable to generate the second fluid, by filling the fluid path system with a storage fluid. During storage, the machine operates the fluid processing device to define, in the fluid path system, one or more recirculation paths that include the fluid pump(s), and operates the fluid pump(s) to displace the storage fluid along the recirculation path(s).

Description

[0001] STORAGE OF MACHINES FOR GENERATION OF MEDICAL FLUID

[0002] Technical Field

[0003] The present disclosure relates to machines for generation of medical fluid and, in particular, to a technique of ensuring operability of such machines when not in use.

[0004] Background Art

[0005] Many medical applications require access to medical fluid. In one example, the medical fluid is purified water, which may be used for cleaning various equipment and / or brought into contact with the body of a patient in connection with a medical treatment. In another example, the medical fluid contains one or more substances which are supplied to a patient for a curative, relieving or other medical purpose.

[0006] One example of a medical treatment is dialysis therapy. Dialysis involves removal of water from the blood of the patient suffering from kidney failure, as well as exchange of solutes with the blood. One type of dialysis therapy is peritoneal dialysis (PD), in which a treatment fluid is infused into the peritoneal cavity of the patient to interface with the blood of the patient through the peritoneal membrane. Another type of dialysis therapy is extracorporeal (EC) blood therapy, in which blood is circulated outside of the patient and interfaced with one or more treatment fluids. Modalities of EC blood therapy include hemodialysis (HD), hemofiltration (HF) and hemodiafiltration (HDF).

[0007] The treatment fluid used in dialysis is an example of a medical fluid. In PD and HD, the treatment fluid is commonly known as dialysis fluid. In HF, the medical fluid is known as replacement fluid, since it is infused into the blood of the patient to replace fluid removed during therapy. In HDF, both dialysis fluid and replacement fluid are used.

[0008] Dialysis therapy is typically automated and performed under control of a dialysis machine. In PD, the machine is known as a cycler, which is connected in fluid communication with the peritoneal cavity and is operated to control the flow of fresh dialysis fluid into the peritoneal cavity and the flow of spent dialysis fluid from the peritoneal cavity. In EC blood therapy, there are two main categories of machines: "chronic machines" for treatment of patient suffering from chronic kidney disease (CKD), and "acute machines" for treatment of patients suffering from acute kidney injury (AKI).

[0009] Over time, dialysis therapy consumes large quantities of treatment fluid. The above-mentioned chronic machines have integrated capability to generate treatment fluid "on-demand" at the point of care, by mixing one or more concentrates with purified water of well-defined quality. It is envisioned that on-demand generation of treatment fluid will be expanded to all types of dialysis therapy in the future.

[0010] Some dialysis machines are in use quite irregularly. For example, dialysis therapy may be performed relatively seldom in an acute setting such as in an intensive care unit (ICU). Thus, the dialysis machine may be stowed away for significant time periods, for example in a storage room. Current acute machines use prefilled bags of ready-made dialysis fluid and a disposable set of fluid paths. When the dialysis machine is no longer to be used, the prefilled bags and the disposable set are simply removed from the dialysis machine and discarded. The dialysis machine is thus configured to never be in direct contact with any fluid and is largely unaffected by the time in the storage room.

[0011] For cost-effectiveness and ease of handling, as well as to reduce the environmental footprint, it may be desirable that a machine for on-demand generation of medical fluid includes re-usable ("permanent") fluid paths, rather than only disposable fluid paths. This also means that pumps and valves will be in direct contact with fluid. Storage of a machine with re-usable fluid paths is more challenging, for example in view of microbiological safety and general operability of the machine after storage.

[0012] Summary

[0013] It is an objective to at least partly overcome one or more limitations of the prior art.

[0014] One objective is to provide a technique of facilitating storage of a machine for generation of medical fluid.

[0015] Another objective is to provide such a technique that ensures at least one of microbiological safety and general operability of the machine after storage.

[0016] One or more of these objectives, as well as further objectives that may appear from the description below, are at least partly achieved by a method of operating a machine, a computer-readable medium, and a machine according to the independent claims, embodiments thereof being defined by the dependent claims.

[0017] The present disclosure proposes a technique of operating a machine for generation of medical fluid. The technique is applicable to the field of dialysis as well as other medical fields. In dialysis, examples of medical fluids include treatment fluids for PD and EC blood therapy, as well as purified water which is used for on-demand generation of treatment fluids. In other medical fields, examples include solutions for intravenous, intramuscular or subcutaneous administration. The proposed technique presumes that the machine includes a fluid processing device for processing a first fluid into a second fluid, which is comprised in the medical fluid, and that the fluid processing device comprises a fluid path system containing one or more fluid pumps. According to the technique, the machine is operated to fill its fluid path system with a storage fluid in preparation for storage. When in storage, the machine is rendered inoperable to generate the second fluid. Storage may, but need not, involve moving the machine from a first location, at which the machine is operated to generate the medical fluid, to a facility that is separated from the first location. The first location may be the point of care, for example at bedside, where the medical fluid is generated and administered to an individual.

[0018] While in storage, the machine operates its fluid processing device to define one or more recirculation paths in the fluid path system, such that the fluid pump(s) are included in the recirculation path(s). For example, the recirculation path(s) may be defined by selective opening and closing of fluid valves in the fluid path system. Also while in storage, the machine operates the fluid pump(s) to displace the storage fluid along the recirculation path(s). If a pump is left stationary in contact with fluid for a longer time the pump may get stuck or its pumping performance may change. This potential problem is mitigated by the pump(s) being activated to pump storage fluid during storage. By defining the recirculation path(s) within the machine, the fluid pump(s) can be activated without any requirement for the machine to be connected to external equipment such as a fluid source, a drain, etc., during storage. This greatly facilitates storage. The operation of the fluid pumps is power efficient and it is possible for the machine to be operated by power from an internal power source, for example a battery. This further facilitates storage by relaxing the need for access to mains power. In some embodiments, the machine also operates to perform a disinfection of at least part of its fluid path system during storage, by operating a disinfection arrangement to process the storage fluid for disinfection as it is circulated in the recirculation path(s). This may be done to prevent or significantly suppress microbiological growth within the machine during storage. A power-efficient disinfection may be achieved by operating one or more irradiation devices in the disinfection arrangement to emit UV radiation onto the circulating storage fluid.

[0019] Still other objectives, aspects, embodiments and technical effects, as well as features and advantages may appear from the following detailed description, from the attached claims as well as from the drawings.

[0020] Brief Description of the Drawings

[0021] FIG. 1 is a schematic diagram of an example dialysis system with on-demand generation of treatment fluid. FIG. 2A is a block diagram of an example machine in the dialysis system of FIG. 1, and FIGS 2B-2C are schematic views of example recirculation paths established in the machine during storage.

[0022] FIG. 3 is a flow chart of an example method of operating a machine before and during storage.

[0023] FIGS 4A-4B are block diagrams of an example water purification machine and an example fluid generation machine.

[0024] FIG. 5 is a block diagram of the machines in FIGS 4A-4B during production of dialysis fluid.

[0025] FIG. 6 is a flow chart of an example method of handling the machines in FIGS 4A-4B between sessions of fluid production.

[0026] FIGS 7A-7B are block diagrams of the machines in FIGS 4A-4B during heat disinfection.

[0027] FIGS 8A-8B are block diagrams of the machines in FIGS 4A-4B during pump activation and UV disinfection.

[0028] FIG. 9 is a block diagram of an alternative to the machine in FIG. 4B during heat disinfection.

[0029] FIG. 10 is a block diagram of a variant of the machine in FIG. 4B during refill of storage fluid.

[0030] FIGS 11A-1 IB are section views of an example port in a connected state and a disconnected state, respectively.

[0031] FIG. 12 is a block diagram of an example control arrangement.

[0032] Detailed Description of Example Embodiments

[0033] Embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all, embodiments are shown. Indeed, the subject of the present disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure may satisfy applicable legal requirements.

[0034] Also, it will be understood that, where possible, any of the advantages, features, functions, devices, and / or operational aspects of any of the embodiments described and / or contemplated herein may be included in any of the other embodiments described and / or contemplated herein, and / or vice versa. In addition, where possible, any terms expressed in the singular form herein are meant to also include the plural form and / or vice versa, unless explicitly stated otherwise. As used herein, "at least one" shall mean "one or more" and these phrases are intended to be interchangeable. Accordingly, the terms "a" and / or "an" shall mean "at least one" or "one or more", even though the phrase "one or more" or "at least one" is also used herein. As used herein, except where the context requires otherwise owing to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, that is, to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments.

[0035] As used herein, the terms "multiple", "plural" and "plurality" are intended to imply provision of two or more elements, whereas the term "set" is intended to imply a provision of one or more elements. The term "and / or" includes any and all combinations of one or more of the associated listed elements.

[0036] It will furthermore be understood that although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing the scope of the present disclosure.

[0037] Like reference signs refer to like elements throughout.

[0038] Well-known functions or constructions may not be described in detail for brevity and / or clarity. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0039] As used herein, "dialysis therapy" or "dialysis" refers to any therapy that replaces or supplements the renal function of a patient by use of a treatment fluid. Dialysis therapy includes, without limitation, extracorporeal (EC) blood therapy and peritoneal dialysis (PD) therapy.

[0040] As used herein, "medical fluid" refers to any liquid or fluent substance that is intended or applicable for a diagnostic, therapeutic or surgical purpose on or within a human or animal body. The term "medical fluid" includes, without limitation, treatment fluid for use in dialysis therapy, as well as product water.

[0041] As used herein, "treatment fluid" refers to a fluid that is supplied to a patient during dialysis therapy and includes, without limitation, dialysis fluids and replacement fluids.

[0042] As used herein, a "machine" is a unitary device.

[0043] As used herein, "heat disinfection" or "heat treatment" refers to a technique of deactivating bacteria and viruses by subjecting them to a fluid at a required temperature for a required time period. The fluid may be water, optionally in combination with a cleaning agent ("disinfectant"). As used herein, "product water" refers to water that has a purity suitable for medical use. In some embodiments, the product water meets criteria of so-called "water for dialysis" "water for injection", or "ultrapure water". For example, criteria for "water for dialysis" or "dialysis water" may be defined in accordance with ANSI / AAMI / ISO 23500-3:2019.

[0044] As used herein, a "durable" component is a component that is intended to be used over an extended time period and be replaced only when deemed necessary during routine maintenance. A durable component may also be denoted "permanent", "nondisposable" or "re-usable" component.

[0045] The present disclosure relates to a technique of ensuring the operability of a machine that is configured for generation of medical fluid, after long-time storage of the machine. In this context, long-term storage is a plurality of days or longer. As mentioned in the Background section, the present disclosure is particularly, but not exclusively, applicable to machines that include durable fluid paths. Unless care is taken, significant microbial growth may occur in these fluid paths during storage. Further, pumps and valves in the machine may get stuck during storage, either from being in contact with fluid or from drying up. Even if the pumps and valves are not stuck, their performance may be changed, for example as a result of deposits in the pump. These problems are addressed by the present disclosure.

[0046] FIG. 1 shows an example dialysis system that is configured to generate treatment fluid, TF, and supply the treatment fluid to a patient 100 during dialysis therapy. The dialysis system is configured to receive supply water, SW, from a water source 11. In some embodiments, the supply water is tap water (drinking water) or some form of pre- processed tap water. Conceptually, the dialysis system may be separated into a water processing system ("water system") 12, a fluid generation system 13 ("mixing system"), and a therapy system 14.

[0047] The water system 12 is operable to process the supply water, SW, into product water, PW. The water system 12 is configured to perform a purification processing of SW to produce PW. As used herein, "purification" refers to removal of impurities such as undesirable chemicals, biological contaminants, suspended solids, and gases. It does not imply that PW is sterile or substantially free of microbial activity, although this may be the case.

[0048] The mixing system 13 is operable to process the product water, PW, into treatment fluid, TF, by mixing the PW with one or more concentrates, TC. A supply arrangement 13' is fluidly connected to the mixing system 13 to supply the one or more concentrates. For example, the supply arrangement 13' may comprise one or more containers of concentrates. As used herein, a "concentrate" is a substance that contains one or more compounds at a concentration that is higher than at the final use of the substance. A concentrate may be in the form a liquid or a powder. A concentrate is capable of being diluted, if a liquid, or dissolved, if a powder, in a solvent. In the context of the present description, the solvent is product water. Dialysis concentrates are commercially available and well-known to the skilled person.

[0049] The therapy system 14 is fluidly connected to receive the treatment fluid, TF, and configured to perform a conventional dialysis therapy by use of the treatment fluid. The dialysis therapy may be peritoneal dialysis (PD) or any modality of extracorporeal (EC) blood therapy.

[0050] The systems 12, 13, 14 may be implemented as physically separate machines, which are fluidly interconnected during operation, as shown in FIG. 1. According to conventional practice, the therapy system 14 is configured to only include disposable fluid paths. As explained in the Background section, such a machine can be put away for storage over an extended time period without causing problems like microbial growth or lack of operational performance after storage. On the other hand, a machine that implements the water system 12 or the mixing system 13 is likely to include durable fluid paths and may be operated in accordance with the present disclosure during storage. As indicated by dashed lines in FIG. 1, the present disclosure is equally applicable to a machine 10a that contains both the water system 12 and the mixing system 13, a machine 10b that contains the mixing system 13 and the therapy system 14, or a machine 10c that contains the water system 12, the mixing system 13 and the therapy system 14.

[0051] FIG. 2A is a block diagram of an example machine 20 that may be operated in accordance with the present disclosure during storage. In the illustrated example, the machine 20 implements the mixing system 13 and is configured to generate medical fluid in the form of treatment fluid. The machine 20 comprises a first inlet line 21 for a product water, an outlet line 22 for treatment fluid, a second inlet line 23 for concentrate, and a drain line 24 for disposing of discarded fluid. The fluid lines 21-24 extend to a respective port 21a, 22a, 23a, 24a, which is exposed on the exterior of the machine 20. A terminal connector 31a on a first connection line 31 is connected to inlet port 21a to provide product water from a water system (cf. 12 in FIG. 1). A terminal connector 32a on a second connection line 32 is connected to outlet port 22a to provide treatment fluid. A terminal connector 33a on a third connection line 33 is connected to concentrate port 23 a to receive concentrate from a supply arrangement for concentrate (cf. 13' in FIG. 1). A terminal connector 34a on a fourth connection line 34 is connected to drain port 24a to extend to a drain (not shown). The fluid lines 21-24 extend from the respective port 21a-24a to a fluid processing device 25, which is configured to process the product water into the treatment fluid by mixing the product water with the concentrate. The fluid processing device 25 comprises a fluid path system 200 which is fluidly connected to the fluid lines 21-24 and used for fluid distribution within the fluid processing device 25. At least a subset of the fluid paths in the fluid path system 200 includes durable fluid paths. The fluid processing device 25 includes a set of fluid pumps, here represented by pumps 26a, 26b, 26c, and functional equipment 27' for performing the function of the fluid processing device 25, which in this case is to generate treatment fluid. The fluid processing device 25 further comprises a disinfection arrangement 27. In the illustrated example, the disinfection arrangement 27 comprises a heating device 27a and an irradiation device 27b for emission of ultraviolet (UV) radiation. The machine 20 further comprises a control device 28 for operating the machine 20, and a power inlet 29 for mains power. The power inlet 29 is connected to a power cable 40, which forms a main connector for connection to a mains outlet 41. The mains outlet 41 may be a conventional wall socket connected to the mains power grid of a building. The power inlet 29 is configured to distribute electrical power to all electric devices in the machine 20, such as the pumps 26a-26c, the heating device 27a, the irradiation device 27b, etc. In the illustrated example, the machine 20 further includes a local power source 30, for example a battery, capacitor, or fuel cell, which is arranged to selectively supply power to the machine 20. In the illustrated example, electrical power is supplied to the machine 20 from the local power source 30 via the power inlet 29, which thus operates as a power controller for the machine 20. The local power source 30 may be a fixed or removable component of the machine 20.

[0052] Although FIG. 2A shows three fluid pumps, the machine 20 many include any number of fluid pumps, including a single fluid pump. Further, even if the fluid lines 21-24 are shown in FIG. 2A as being outside of the fluid generation device 25, they may actually be part of the fluid path system 200 in the fluid generation device 25. It is also possible that the ports 21a-24a are part of the fluid generation device 25.

[0053] In a variant, corresponding to the dashed box 10b in FIG. 1, the machine 20 additionally includes the therapy system 14.

[0054] In a first alternative example, the fluid processing device 25 is instead configured to implement the functionality of the water system 12. Thus, the machine 20 is configured to generate medical fluid in the form of product water. In the first alternative example, the first inlet line 21 is arranged to receive supply water, the outlet line 22 is arranged to supply product water, the second inlet line 23 is omitted, and the fluid processing device 25 is configured to process supply water into product water.

[0055] In a second alternative example, corresponding to the dashed box 10a in FIG. 1, the fluid processing device 25 implements the functionalities of the water system 12 and the mixing system 13. Thus, the machine 20 is configured to generate medical fluid in the form of treatment fluid. In the second alternative example, the first inlet line 21 is arranged to receive supply water, the outlet line 22 is arranged to supply treatment fluid, the second inlet line 23 arranged to receive concentrate, and the fluid processing device 25 is configured to process supply water into product water and mix the product water with the concentrate.

[0056] In a variant the second alternative example, corresponding to the dashed box 10c in FIG 1, the machine 20 additionally includes the therapy system 14.

[0057] Generally, the machine 20 may be seen to include an inlet connector or port 21a for releasable connection to a source of a first fluid, a fluid processing device 25 for processing the first fluid into a second fluid, which is comprised in the medical fluid, and an outlet connector or port 22a for releasable connection to a device for receiving the second fluid.

[0058] FIG. 3 is a flowchart of an example method Ml of operating a machine for generation of medical fluid. The method Ml will be described in the context of dialysis and with reference to the machine 20 in FIG. 2A. The method Ml may be performed by the control device 28 of the machine 20. Optional steps are indicated by dashed lines.

[0059] The method Ml implements a technique of ensuring operability of the machine 20 after long-time storage. During storage, the machine 20 is inoperable to perform its ordinary operation of generating and supplying the second fluid. In this context, "inoperable" implies that the machine 20 is rendered unable to perform its ordinary operation, for example through lack of proper fluid connections and / or by being reconfigured structurally. The time period during which the machine 20 is placed in storage is denoted "storage period" herein. The method Ml is performed before and during the storage period. For example, the method Ml may be started after completion of a dialysis therapy when it is known that the machine 20 will no longer be needed. The method Ml may be particularly, but not exclusively, useful in acute settings, in which the machine 20 may not be needed for extended time periods.

[0060] In step S10, the machine is prepared for the storage. As shown, step S10 includes a step S 10a of operating the machine to fill the fluid path system 200 with a storage fluid. In some embodiments, the storage fluid is supply water, SW, product water, PW, treatment fluid, TF, or one or more concentrates, TC. In some embodiments, the storage fluid is generated by the machine 20 to include a cleaning agent, presuming that the machine 20 is connected to or includes a supply of cleaning agent. Non-limiting examples of cleaning agents include acetic acid, citric acid, or peracetic acid. In some embodiments, the storage fluid is bacteriostatic. A bacteriostatic fluid may comprise a bacteriostatic agent, which is a biological or chemical agent that stops bacterial growth, or even kills bacteria (also known as bactericidal agent). In some embodiments, the bacteriostatic fluid includes at least one concentrate that is available to the machine via the supply arrangement (cf. 13' in FIG. 1). For example, electrolyte concentrates and glucose concentrates proposed for generation of treatment fluid for PD may be designed such that they are inherently bacteriostatic. Similarly, many concentrates for use in generation of treatment fluid for EC blood dialysis are bacteriostatic, for example acid (A) concentrates.

[0061] In step Si l, which is performed during the storage period, the fluid processing device 25 is operated to define or establish one or more recirculation paths in the fluid path system 200, so that the fluid pumps 26a-26c are included in the one or more recirculation paths. The respective recirculation path is typically defined by operating a system of valves ("valve arrangement") in the fluid processing device 25 to open a selected pathway through the fluid path system 200. As used herein, a recirculation path is defined to allow the storage fluid to circulate within the machine 20. Step Si l is performed by the machine 20 without user interaction. Thus, the user is not required to perform any action during step Si l such as connect dedicated tubing to extend between ports on the machine 20 so as to establish the recirculation path(s). In other words, the machine 20 is operable to autonomously establish the respective recirculation path.

[0062] In step S12, which is performed during the storage period, the fluid pumps 25a- 25c are operated to displace the storage fluid along the recirculation path(s). Thereby, the storage fluid is circulated within the machine 20 during the storage period. It is realized that step S12 presumes that the respective recirculation path defines a flow path that extends from an outlet of a fluid pump to an inlet of the same fluid pump.

[0063] Steps S11-S12 will ensure that the fluid pumps 25a-25c are "exercised" during the storage period. This will mitigate the risk that the fluid pumps do not operate properly after the storage period. It is to be understood that the fluid pumps need only be activated by step S12 for a short time period during the storage period. In some embodiments, the respective fluid pump is activated repeatedly during the storage period, for example at a predefined time interval. For example, steps SI 1-S12 may be performed at least once every 24 hours or 48 hours.

[0064] In some embodiments, steps SI 1-S12 are performed to activate all fluid pumps that are used by the fluid processing device 25 when performing its function of processing the first fluid into the second fluid. This may or may not involve all fluid pumps in the machine 20. For example, as described below with reference to FIG. 4B, the machine may include a fluid pump for handling spent treatment fluid and this fluid pump may or may not be exercised during the storage period. The fluid pumps in the machine 20 may be of any type, including but not limited to piston pumps, rotary vane pumps, gear pumps, screw pumps, centrifugal pumps, etc.

[0065] It is realized that steps SI 1-S12 may be performed to exercise other devices with one or more moveable parts in the machine 20, in addition to fluid pumps, such as on / off valves, 3-way valves, adjustable restrictors, etc. In this context, "exercise" implies that the one or more moveable parts are set in motion.

[0066] The control device 28 may be configured to detect the start of the storage period in many different ways. In one example, the user may enter a dedicated command to the machine 20, for example via a user interface on the machine 20. In another example, the storage period may be inferred based on one or more actions performed by the user, for example that the machine 20 is disconnected from mains power and / or that some or all connectors are detached from the ports of the machine 20, assuming that the machine 20 includes sensors for detection of such detachment. It is also conceivable that output data from a motion or position sensor in the machine 20 is used for detecting that the machine 20 is moved into a storage facility. Generally, the control device 28 may be seen to set the machine 20 in a storage mode upon detection of a first event that is indicative of the start of the storage period. In the storage mode, the machine 20 is configured to perform steps S11-S12, and optionally step S13 (below). Correspondingly, the control device 28 may been seen to terminate the storage mode upon detection of a second event that is indicative of the end of the storage period. The second event may be a dedicated command, one or more dedicated actions performed by the user, output data from the motion or position sensor, etc.

[0067] FIG. 2B is a schematic view of a single recirculation path la that is established within the fluid processing device 25 to include the fluid pumps 26a-26c. In the drawings, a filled triangle indicates that a fluid pump is operating. Thus, in FIG. 2B, the fluid pumps 26a-26c are jointly operated to circulate the storage fluid in the recirculation path la.

[0068] If plural recirculation paths are to be defined during the storage period, step S12 may be performed after establishment of the respective recirculation path by step Si l. FIG. 2C is a schematic view of three recirculation paths la, lb, 1c that are sequentially established within the fluid processing device 25. A respective one of the fluid pumps 26a-26c is included each of the recirculation paths la-lc and operated to circulate the storage fluid in the respective recirculation path la-lc.

[0069] As shown in FIG. 3, step S10 may include one or more additional steps SlOb- SlOd to prepare the machine 20 for the storage period.

[0070] In step SlOb, one or more of the fluid pumps 26a-26c and the heating device 27a are jointly operated to perform a heat treatment ("heat disinfection") of at least part of the fluid path system 200. The heat disinfection aims at inactivating microbes in the machine 20.

[0071] In step SlOc, the operator is caused to disconnect the upstream source from the inlet connector 21a and / or to disconnect the downstream device from the outlet connector 22a. Step SlOc may be performed by providing an instruction on a user interface on the machine 20. Step SlOc implies that the machine 20 will remain disconnected from the upstream source and / or the downstream device throughout the storage period. Step SlOc also implies that the machine 20 is operable to perform subsequent steps SI 1-S13 while it is fluidly disconnected from the upstream source and / or the downstream device. Step SlOc eliminates the need for the upstream source and / or the downstream device to be present or available in the storage facility where the machine 20 is to be stored. For example, if the machine 20 includes the water system 12 (FIG. 1), it may be desirable for the machine 20 to be disconnected from the water source (11 in FIG. 1) during the storage period. This will eliminate the requirement for the storage facility to provide access to tap water. The same applies if the machine 20 is configured to include the mixing system 13 (FIG. 1). Disconnecting the machine 20 from the downstream device will also increase the flexibility of storing the machine 20.

[0072] Step SlOc may also involve causing the operator to disconnect the connection line 34 from the drain port 24a. Again, this implies that the drain port 24a will remain disconnected throughout the storage period, which will eliminate the requirement for the storage facility to have a drain. As part of step SlOc, the operator may also be instructed to disconnect the supply arrangement (13' in FIG. 1) from the machine 20.

[0073] In some embodiments, step SlOc is performed so that the machine 20 is freestanding and independent of any other device, whether it is a water source, another machine, a drain, etc.

[0074] Step SlOd involves causing the machine 20 to switch from using mains power to using local power. In the example of FIG. 2A, instead of obtaining electrical power via the power cable 40, the machine 20 obtains its electrical power from the local power source 30. Step SlOd may be automatically performed as the operator unplugs the power cable from the mains power outlet 41. Alternatively, step SlOd may be performed by the operator actively instructing the machine 20 to switch to local power, for example via a user interface on the machine.

[0075] Step SlOd implies that the machine 20 will remain on local power throughout the storage period. Step SlOd also implies that the machine 20 is operable to perform subsequent steps S11-S13 while on local power. Step SlOd will eliminate the need for the storage facility to provide access to mains power. As shown in FIG. 3, the method Ml may further include a step S13, in which the disinfection arrangement 27 is operated, during the storage period, to process the storage fluid for disinfection while the storage fluid is circulated in the one or more recirculation paths. Step S13 presumes that the respective recirculation path to be disinfected extends through the disinfection arrangement 27, for example as shown in FIGS 2B-2C. Step S13 will result in a disinfection of the recirculation path(s).

[0076] Depending on implementation, step S13 may be performed so that all of the fluid path system 200 is disinfected. This may be achieved by step Si l defining the recirculation path(s) to include all parts of the fluid path system 200. With reference to FIG. 2A, it may be noted that the inlet and outlet lines 21, 22 and the associated ports 21a, 22a may be included in the recirculation path(s). Thereby, these parts will also be subjected to the disinfection by S13, resulting in a more complete disinfection of the fluid paths in the machine 20. Further, if present, the inlet line 23 and the associated concentrate port 23a may be included in the recirculation path(s). Examples of how to include a port in a recirculation path will be given with reference to machines shown in FIGS 4A-4B below.

[0077] In one embodiment, step S13 results in a heat disinfection and is performed by operating the heating device 27a to heat the storage fluid to a disinfection temperature while the storage fluid is circulated in the respective recirculation path la-lc through the pumping action of one or more of the fluid pumps 26a-26c. It is understood that more than one heating device 27a may be used in step S13. The use of heat disinfection is likely to result in large power consumption during the storage period and may require the machine 20 to be connected to mains power.

[0078] As noted above, it may be desirable for the machine 20 to be operable only on local power throughout the storage period. By insightful reasoning, the Applicant has found that this may be achieved by irradiating the storage fluid with UV radiation in step S13. Power consumption for generation of UV radiation is quite limited. Thus, in some embodiments, step S13 involves operating the irradiation device 27b to emit UV radiation onto the storage fluid while the storage fluid is circulated in the respective recirculation path la-lc through the pumping action of one or more of the fluid pumps 26a-26c. It is understood that more than one irradiation device 27b may be used in step S13.

[0079] Heat disinfection not only disinfects the fluid but also uses the heated fluid as a medium for disinfecting the fluid paths. UV irradiation only disinfects the fluid itself. Thus, compared to heat disinfection, UV irradiation is less efficient in disinfecting the fluid paths inside the machine 20. However, the use of UV irradiation is sufficient to suppress the microbial activity in the storage fluid during the storage period, for example to prevent the microbial activity in the storage fluid from exceeding a predefined limit.

[0080] If step S13 involves heat disinfection, the duration of step S13 for the respective recirculation path may be predefined. Alternatively, the duration may be dynamically determined in accordance with the AO concept. This means that the heat disinfection is performed to achieve a predefined AO value. An AO value may be calculated according to: AO = 1Q(7’_80) / Z■ At , where T is the fluid temperature (in °C), z is a bacteria coefficient, and At is the exposure time at the fluid temperature. By use of this equation, a value of the microbial deactivation may be calculated, by summation or integration, during heat-up, holding, and cooling of any moist heat disinfection process. For example, a condition for sufficient heat disinfection may be that the AO value is at least 500, 600, 700, 800 or 900. Generally, the fluid temperature needs to exceed 65°C to be effective. The use of the A0 concept presumes that the fluid temperature in the fluid path system 200 is measured during heat disinfection, so that the fluid temperature at the coldest location in the respective recirculation path is known or estimated.

[0081] If step S13 involves UV irradiation, the duration of step S13 for the respective recirculation path may be predefined. For example, the duration may be selected to that N times the fluid volume in the respective recirculation path is pumped through the irradiation device 27b with a predefined residence time or dwell time in the irradiation device 27b. The predefined residence time may be set so that a complete or at least significant microbial deactivation is achieved. The value of N is at least 1. To provide a safety margin, N may be set to at least 2 or at least 3.

[0082] The irradiation device 27b comprises at least one source of UV radiation. The UV source may comprise any element capable of generating UV radiation, including but not limited to a light-emitting diode (LED), a laser diode, a fluorescent lamp, an incandescent lamp, a gas-discharge lamp, etc. To reduce power consumption and cost, the UV source may comprise one or more LEDs or laser diodes. LEDs and laser diodes also have a small footprint, long operative life, and a well-defined emission spectrum. The irradiation device 27b may be configured to generate UV radiation in the UV-C range (200-280 nm). In a non-limiting example, UV-C radiation at one or more wavelengths in the range of 260-270 nm is used.

[0083] Step S13 is typically performed for a limited time period during the storage period. Step S13 may be performed repeatedly, at multiple instances, during the storage period. Step S13 is performed while step S12 is being performed. It is conceivable that step S13 is performed more seldom than step S12. In some embodiments, steps S11-S13 are jointly performed at least once every 24 hours or 48 hours. In some embodiments, during the storage period, one or more instances of step S13 involve heat disinfection and one or more instances of step S13 involve UV irradiation. It is also conceivable that one or more instances of step S13 include both heat disinfection and UV irradiation.

[0084] The method Ml will be further exemplified with reference to machines shown in FIGS 4A-4B. It is to be understood that the machines in FIGS 4A-4B are non-limiting examples, which are provided for the purpose of describing the method Ml in a more specific context. In the following, the treatment fluid is denoted "dialysis fluid".

[0085] FIG. 4A is a block diagram of a first machine ("water machine") that is configured to generate product water from supply water. Specifically, the first machine contains a water system 12, which is confined within a chassis or casing 12'. Three ports P1-P3 are exposed on the outside of the chassis 12'. Pl is arranged for connection to a water source, P2 is arranged for connection to a downstream device that receives the product water, and P3 is arranged for connection to a drain. The first machine is operated by a control device (not shown), which corresponds to the control device 28 in FIG. 2A.

[0086] FIG. 4B is a block diagram of a second machine ("mixing machine") that is configured to generate dialysis fluid from product water. Specifically, the machine contains a mixing system 13, which is confined within a chassis or casing 13'. Five ports P4-P8 are exposed on the outside of the chassis 13'. P4 is arranged for connection to a source of product water, for example the first machine in FIG. 4A, P5 is arranged for connection to a therapy system (cf. 14 in FIG. 1) that receives the dialysis fluid, P6 is arranged for connection to a supply arrangement for concentrate, P7 is arranged for connection to the therapy system to receive spent dialysis fluid, and P8 is arranged for connection to a drain. As used herein, "spent dialysis fluid" refers to dialysis fluid that has been used in a dialysis therapy. The first machine is operated by a control device (not shown), which corresponds to the control device 28 in FIG. 2A.

[0087] The various components of the machines in FIGS 4A-4B will now be described, followed by a description of how the machines are interconnected and jointly operated to produce dialysis fluid, with reference to FIG. 5. Then, the handling and operation of the machines before, during and after storage will be described with reference to FIGS 6-8.

[0088] With reference to FIG. 4A, the water system 12 comprises a fluid line LI, which extends from the port Pl to a tank or reservoir 104. It is assumed that the incoming supply water is sufficiently pressurized to flow along LI into the tank 104. In the flow direction along LI, there is a one-way valve 101, an on / off valve VI, a filtration device 102, a flow restrictor 103, and an on / off valve V2. The valve VI is operable to selectively open and close LI to control admission of supply water. The one-way valve 101 is included to prevent flow reversal in LI and thus backflow through the filtration device 102. The filtration device 102, denoted pre-filter package (PFP) herein, is configured to perform both removal of particles and dechlorination. In the illustrated example, the PFP 102 comprises activated carbon (AC) filters 102a, 102b, which are connected in series. Each AC filter 102a, 102b is formed by a container that holds a bed of activated carbon. The bed of activated carbon is arranged to remove chemical compounds of chlorine, and to absorb toxic substances and pesticides. In an example embodiment, the bed of activated carbon is arranged to remove free and combined forms of chlorine. In a further example embodiment, the bed of activated carbon is also arranged to reduce organic compounds (TOC, total organic carbon) including pesticides. The bed of activated carbon also inherently filters out particles. The flow restrictor 103 creates a backing pressure in LI to limit the flow rate of water through the PFP 102 and also serves to maintain an approximately constant flow rate of water into the tank 104 even if the inlet pressure of supply water fluctuates.

[0089] The tank 104 is arranged to receive and collect the water from LI. The tank 104 comprises a level sensor 105, which is configured to indicate at least one fluid level in the tank 104, via an output signal SI. The level sensor 105 may thus signal when the water reaches one or more discrete levels, or indicate the fluid level along a continuous scale. The signal SI allows the control device to control the level of water in the tank 104. The tank 104 comprises a plurality of ports 104a- 104d. An inlet port 104a is defined in the top portion of the tank 104 and connected to LI. An outlet port 104b is defined in the bottom portion of the tank 104 and connected to a fluid line L2. An inlet port 104c is defined in the top portion of the tank 104 and connected to a fluid line L7. In some embodiments, at least one of the inlet ports 104a, 104c is connected to a spray nozzle (not shown) inside the tank 104 to disperse the incoming water. A gas outlet or vent 104d is defined in the top portion of the tank 104. The vent 104d allows gases to escape from the tank 104, and also allows air to enter the tank as needed. The water is thus held in the tank 104 at atmospheric pressure.

[0090] In the illustrated example, an irradiation device 106 ("UV generator") for generation of UV radiation is arranged in the tank 104 above the maximum fluid level. The UV generator 106 is thus never immersed in water. The UV generator 106 corresponds to device 27b in EIG. 2A. The UV generator 106 may be operated to disinfect the inner surfaces of the tank 104 above the water level in the tank 104, and any water stuck on these inner surfaces.

[0091] The fluid line L2 extends from the outlet port 104b on the tank 104 to the port P2. In the flow direction along L2, there is an irradiation device ("UV generator") 107, a heating device ("heater") 108, a fluid pump EPl, a reverse osmosis (RO) unit 109, an irradiation device ("UV generator") 111 and a sensor arrangement 112. The UV generators 107, 111 correspond to device 27b in FIG. 2A. Depending on implementation, the sensor arrangement 112 is configured to measure at least one of a temperature, pressure, flow rate or conductivity. The output of the sensor arrangement 112 is designated S2 and may include a plurality of separate output signals. The heater 108 is operable to electrically heat the water, for example during heat disinfection. In some embodiments, the heater 108 is a flow-through electrical heater. In some embodiments, the control device operates the heater 108 by feedback control based on a temperature measured by the sensor arrangement 112 (cf. signal S2).

[0092] The RO unit 109 is of conventional structure and comprises a semi-permeable filter or membrane 109'. RO units are well-known in the art and will not be described in detail. The membrane 109' separates the body of the RO unit 109 into a feed side or chamber and a permeate side or chamber. The RO unit 109 is interposed in the fluid line L2 to define a flow path from the feed side to the permeate side via the membrane 109'. A fluid line L3 is connected to a retentate outlet on the feed side of the RO unit 109. The fluid line L3 extends from the RO unit 109 to the fluid line L2, at a junction upstream of FP1. A fixed flow restrictor 110 is arranged in L3. A fluid line L4 extends between locations in L3 upstream and downstream of the flow restrictor 110. A flow control valve V5 is arranged on L4 and is operable, by the control device, to change the flow resistance in L4. The flow control valve V5 may also be denoted motorized valve, motorized restrictor, variable restrictor, or adjustable restrictor. Downstream of the flow restrictor 110 in L3, there is a 3-way valve V3, which is operable to either direct fluid along L3 or from L3 into a fluid line L3' that extends to the drain port P3. An on / off valve V4 is arranged in L3 downstream of V3.

[0093] A return path L5 extends from the outlet port P2 via an on / off valve V6 to a 3- way valve V7, which is operable to either establish fluid communication between L5 and a fluid line L6 that extends to Pl, or a fluid line L7 that extends to the inlet port 104c on the tank 104.

[0094] With reference to FIG. 4B, the mixing system 13 comprises a fluid line L8, which extends from the inlet port P4 to an inlet on a lumen side of an ultrafilter 120. Ultrafilters are well-known in the art and will not be described in detail. A 3-way valve V8 and an on / off valve V9 are arranged in sequence in L8. The valve V8 is connected to a fluid line LI 4. A fluid line L9 extends to a heating chamber 123 from an outlet on a permeate side of the ultrafilter 120. A fluid line L10 extends to P4 from an outlet on the lumen side of the ultrafilter 120 via an on / off valve V10.

[0095] The heating chamber 123 comprises a heating device 124, which is arranged to be submerged in fluid within the chamber 123. The heating device 124 is an electrical heater. In the illustrated example, a UV generator 125 is arranged in the chamber 123 above the maximum fluid level. The UV generator 125 corresponds to device 27b in FIG. 2A. The UV generator 125 may be operated to disinfect the inner surfaces of the chamber 123 above the fluid, and any fluid stuck on the inner walls. A level sensor 126 is arranged to indicate at least one fluid level in the chamber 123, via an output signal S3. The level sensor 126 may be configured by analogy with the level sensor 105 in FIG. 4A. The chamber 123 is a closed vessel. A fluid line LI 1 is connected to a top portion of the chamber 123 and extends to a filter 127, for example a hydrophobic filter, via an on / off valve VI L A fluid line L12 extends from a bottom portion of the chamber 123 to the outlet port P5. The purpose of the heating chamber 123 is to heat incoming product water to effectively deactivate any microorganisms that may be present in the product water, while also causing gases to be released from the product water. In some embodiments, the product water in the chamber 123 is heated to at least 85°C, given by a temperature sensor (not shown). A heat transfer arrangement 122 is arranged to selectively transfer heat between L9 and L12. In the flow direction along L12, downstream of the heat transfer arrangement 122, there is a junction to a fluid line L16, a junction to a fluid line L15, a mixing chamber 128, a fluid pump ("main pump") FP2, a first sensor arrangement 129, a junction to a fluid line L17, an on / off valve V13, and second sensor arrangement 130. The fluid line L15 extends from the concentrate port P6 to L12 and includes a fluid pump ("concentrate pump") FP3. The fluid line L16 extends from the port P6 to L12 and includes an on / off valve V15. The mixing chamber 128 is configured to have the additional function of capturing and accumulating gas from passing fluid. A fluid line L13 extends from the top of the chamber 128 to a junction on L12 downstream of the chamber 128. An on / off valve V12 is arranged in LI 3. The sensor arrangement 129 is configured to at least measure the conductivity and the temperature of the passing fluid and generate corresponding signals, collectively represented by signal S4. The sensor arrangement 130 may be configured to at least measure fluid pressure and generate a corresponding signal S5.

[0096] Reverting to the heat transfer arrangement 122, this is operated to lower the temperature of the product water in L12 so as to achieve a target temperature at the sensor arrangement 129 during production of dialysis fluid. The target temperature may be in the range of 30-37°C. In some embodiments, the heat transfer arrangement 122 comprises a combination of a heat exchanger and a heat pump.

[0097] A fluid line L14 extends from the outlet port P5 to the 3 -way valve V8. An on / off valve V14 and a UV generator 131 are arranged in LI 4. The UV generator 131 corresponds to device 27b in FIG. 2A. The fluid line L17 extends to a 3-way valve V16, which is further connected to fluid line LI 8 and fluid line L22. Fluid line LI 8 extends to a junction on LI 4, and fluid line L22 extends to a junction on fluid line LI 9.

[0098] In the illustrated example, the mixing machine may be seen to include a main fluid system 200a for use in generating the dialysis fluid, and an auxiliary fluid system 200b for handling spent dialysis fluid.

[0099] The auxiliary fluid system 200b is connected to the ports P7, P8. The fluid line LI 9 extends between P7 and P8, via a UV generator 132, an on / off valve VI 7, a bubble trap 133, the junction to L22, and a fluid pump ("drain pump") FP4. The bubble trap 133 is arranged to capture and dispose of gas bubbles before they reach FP4. To this end, a fluid line L20 extends from top of the bubble trap 133, via an on / off valve VI 8 to a junction in a fluid line L21, which extends between P7 and P8 in parallel to LI 9.

[0100] In the illustrated example, a heat exchanger (HX) 121 is arranged to transfer heat between L9 and L19. The HX 121 is interposed in L9 upstream of the heat transfer arrangement 122. The HX 121 is provided to reduce the power consumption of the mixing system 13, based on the understanding that to the extent that spent dialysis fluid and product water co-exist in the HX 121, the spent dialysis fluid is generally warmer than the product water.

[0101] FIG. 5 is block diagram of the machines in FIGS 4A-4B during operation for production of dialysis fluid. In these and subsequent figures, thick lines indicate fluid lines with flowing fluid, and arrows indicate the flow direction. Further, a closed valve is unfilled, an open valve is filled, an inactive pump is indicated by an open triangle, and an operating pump is indicated by a filled triangle.

[0102] In FIG. 5, the water machine and the mixing machine are fluidly connected by a connecting line CL23. A first terminal connector C2 on CL23 is connected to the outlet port P2 of the water machine, and a second terminal connector C3 on CL23 is connected to the inlet port P4 of the mixing machine. A connecting line CL1 is connected via a connector Cl to provide supply water to the inlet port Pl of the water machine. A connecting line CL3 is connected via a connector C3 to the drain port P3 of the water machine to direct fluid to a drain. A connecting line CL5 is connected via a connector C5 to the outlet port P5 of the mixing machine to provide dialysis fluid to a therapy system. A connecting line CL6 is connected via a connector C6 to the concentrate port P6 on the mixing machine. The connecting line CL6 extends to a container CB that holds a concentrate. The container CB corresponds to the supply arrangement 13' in FIG. 1. A connecting line CL7 is connected via a connector C7 to port P7 to provide spent dialysis fluid, and a connecting line CL8 is connected via a connector C8 to direct the spent dialysis fluid to a drain. In FIG. 5, the tank 104 contains supply water that has passed the PFP 102, as well as filtered water that is recirculated back to the tank 104 via L5, L7. The feed pump FP1 is operating to pump water into the feed side of the RO unit 109. Thereby, filtered water ("permeate") passes through the membrane 109', and reject water ("retentate") exits the RO unit 109 on L3. The reject water flows back to L2 via L3, L4. The fluid pressure on the feed side of the RO unit 109 is defined by the feed pump FP1 and the flow control valve V5. The pumping rate of the feed pump FP1 is typically held constant. The fluid pressure on the feed side may be monitored via a pressure sensor (not shown) and controlled by adjustment of the valve V5. Although not shown in FIG. 5, a conductivity sensor may be arranged in L3 or L4. Based on the measured conductivity, the valve V3 is intermittently operated to direct reject water to drain as indicated by a dashed arrow. The filtered water from the RO unit 109 flows back to the tank via P2, L5 and L7. This filtered water is product water that is made available to the mixing machine, which is operated to divert a desired flow of product water via CL23. Since product water is diverted from the water machine, and since reject water is intermittently directed to drain, the fluid level in the tank 104 will decrease over time. The valve VI is intermittently opened to admit supply water into the tank 104 via the PFP 102, as indicated by dashed arrows.

[0103] The mixing machine is operated to receive a flow of product water from the water machine. The product water flows via the ultrafilter 120 into the heating chamber 123, where the product water is heated and degassed. The pressure in the chamber 123 is atmospheric, since the valve VI 1 is open. The product water then passes the heat transfer arrangement 122, in which it is cooled to achieve a target temperature of the dialysis fluid that leaves the mixing machine. The flow rate of the dialysis fluid is set by the speed of the main pump FP2. The flow rate of the concentrate is set by the speed of the concentrate pump FP3. The flow rate of product water is given by the difference in flow rates between FP2 and FP3. The mixing ratio of concentrate and product water is given by the speeds of FP2 and FP3. These speeds may be determined in a start-up procedure, in which the fluid flow is diverted to drain via L17, V16 and L19, while the main pump FP2 is operated to generate a target flow rate and the speed of the concentrate pump FP3 is adjusted until the conductivity at the sensor arrangement 129 meets a target conductivity. The speeds of FP2 and FP3 are then used during operation for production of dialysis fluid.

[0104] During fluid production, the mixing chamber 128 may be gradually filled with gas. This gas is released by diverting the fluid flow to drain and opening valve V12.

[0105] In the illustrated example, the mixing machine is operated to receive spent dialysis fluid while it is being operated to generate dialysis fluid. This situation may, for example, be relevant during EC blood treatment by HF or HDF. The flow of spent dialysis fluid is set by the drain pump FP4, which is operated to pump the spent dialysis fluid from P7 along E19 and via P8 to drain. Over time, the bubble trap 133 may be gradually filled with gas. This gas is released by opening valves V18, V19. The pumping action of FP4 will drive this gas together with spent dialysis fluid along E20, E21 and via P8 to drain.

[0106] FIG. 6 is a flow chart of an example method M2 of handling the machines in FIGS 4A-4B between uses. The method M2 may be initiated while the machines are operated in accordance with FIG. 5. In step S20, the production of dialysis fluid is stopped. Step S20 results in both machines being stopped. Step S20 may be performed manually by an operator, for example via a user interface on the respective machine, or automatically based on internal or external control signals. The external control signals may be generated by an overall control system or by the therapy system that receives and uses the dialysis fluid. In step S21, the patient is disconnected from the therapy system. In step S22, the container CB (FIG. 5) with concentrate is disconnected from the mixing machine. An optional step S23 is performed to remove one or more functional components from the respective machine before storage. For example, such functional components may be known to promote excessive microbiological growth during storage, be difficult to effectively disinfect during storage, or be damaged if exposed to heat disinfection. In the machines of FIGS 4A-4B, the PFP 102, the RO unit 109, and the ultrafilter 120 may be such components. Each such component may be replaced with a bypass device, which is installed to provide the same flow path(s) as the respective component. The removed components are suitably discarded. FIG. 7A shows bypass devices 102a, 109a that are installed in the water machine to replace the PFP 102 and the RO unit 109, respectively. FIG. 7B shows a bypass device 120a that is installed in the mixing machine to replace the ultrafilter 120.

[0107] Then, the method Ml is performed. Returning to FIG. 3, the fluid paths of respective machine are filled ("primed") with a storage fluid (step SlOa). In the following examples, it is assumed that storage fluid is product water. For example, the mixing machine may be first filled with product water provided by the water machine, and the water machine may then be operated to fill its fluid paths with product water. During this priming, the machines are suitably connected to drain.

[0108] Then, in accordance with step SlOb, the machines may be operated to perform a heat disinfection. The heat disinfection may be performed while the machines are still connected to each other (cf. FIG. 5), or when the connecting line CE23 has been disconnected from the machines in step S 10c. If performed while the machines are connected, the heat disinfection may be performed jointly for both machines, or in each machine separately. The preparatory heat treatment by step SlOb is optional but may be beneficial for microbial safety. An example of the heat disinfection in step SlOb is given further below with reference to FIGS 7A-7B.

[0109] Then, in accordance with an embodiment of step SlOc, the operator removes fluid connections from the respective machine. The water machine is disconnected from the water source (at port Pl), the mixing machine (at port P2), and the drain (at port P3). This renders the water machine fluidly self-contained. The mixing machine is disconnected from the water machine (at port P4), the therapy system (at ports P5, P7), and the drain (at port P8). This renders the mixing machine fluidly self-contained.

[0110] Then, in accordance with step SlOd, the operator may unplug the machines from mains power, causing the machines to operate on local power only. This renders the machines electrically self-contained. It is preferable to perform the heat disinfection of step SlOb before step SlOd, to ensure that the local power source (30 in FIG. 2A) is fully charged when the respective machine starts to operate on local power.

[0111] At this stage, the machines are moved into a storage facility, which does not need to have a water tap, a drain or a mains power outlet.

[0112] While in the storage facility, steps S11-S13 are performed intermittently to both exercise the fluid pumps and perform a disinfection of the fluid paths in the respective machine. An example of the in-storage operation according to steps S11-S13 is given further below with reference to FIGS 8A-8B.

[0113] When the machines are later needed once again, they are collected from the storage facility and moved to the point of care. Then, in accordance with step S24 (FIG. 6), the operator establishes fluid connections to the respective machine. The water machine is connected to the water source (at port Pl), the mixing machine (at port P2), and the drain (at port P3). The mixing machine is connected to the water machine (at port P4), the therapy system (at ports P5, P7), and the drain (at port P8). In step S25, the operator connects the water machine and the mixing machines to mains power. In step S26, the water machine and the mixing machine are operated by their control devices to flush the storage fluid to drain. This removes any endotoxins that may be present in the storage fluid as result of the disinfection performed during storage. Endotoxins are known to be released from bacteria when they are killed. For example, the water machine may be first flushed by admitting supply water and processing the supply water into product water, while diverting reject water to drain. The product water is suitably circulated through all fluid paths of the water machine to completely expel all storage fluid. When the water machine has been flushed, the mixing machine may obtain product water from the water machine and circulate the product water while diverting water to drain. The product water is suitably circulated through all fluid paths of the mixing machine to completely expel all storage fluid. In the example of FIG. 4B, the mixing machine may or may not be operated to expel storage fluid from the auxiliary fluid system 200b. In step S27, the machines may be operated to perform a heat disinfection by analogy with step SlOb. The heat treatment by step S27 is optional but may be beneficial for microbial safety. In step S28, any bypass devices that were installed in step S23 are removed and replaced with new functional components. In the machines of FIGS 4A-4B, a new PFP 120 and a new RO unit 109 may be installed in the water machine, and a new ultrafilter 120 may be installed in the mixing machine. In step S29, a new container CB of concentrate is connected to the mixing machine (at port P6). In step S30, the therapy system is connected to the mixing machine (at ports P5 and P7). In step S31, the production of dialysis fluid is started. As noted above, the mixing machine may perform a start-up procedure before starting to supply dialysis fluid.

[0114] FIG. 7A shows the water machine of FIG. 4A during an example heat disinfection. As noted above, the PFP 102 and the RO unit 109 have been replaced with a respective bypass device 102a, 109a. The valves V1-V7 are set to define a recirculation path that includes the heater 108. The fluid pump FP1 is operated to circulate the storage fluid along the recirculation path while the heater 108 is operated to heat the passing storage fluid. It may be noted that the tank 104 is open to the surroundings via port 104d. The tank 104 thereby provides compliance to the water system 12, by allowing the storage fluid to expand when heated without changing the pressure in the water system 12. As seen, some flow paths are not subjected to the heated storage fluid, including fluid lines L4, L7. To heat disinfect fluid line L4, another recirculation path may be defined by opening V5 and closing V4. To heat disinfect fluid line L7, yet another recirculation path may be defined by switching V7 to be open towards L7 and closed towards L6.

[0115] FIG. 7B shows the mixing machine of FIG. 4B during an example heat disinfection. As noted above, the ultrafilter 120 has been replaced with a bypass device 120a. For heat disinfection of the main fluid system 200a, the valves V8-V16 are set to define a recirculation path that includes the heating chamber 123. The fluid pumps FP2, FP3 are operated to circulate the storage fluid along the recirculation path while the heater 124 in the heating chamber 123 is operated to heat the storage fluid therein. During the heat disinfection, Vl l is open. The heating chamber 123 thereby provides compliance to the mixing system 13, by allowing the storage fluid to expand when heated without changing the pressure in the mixing system 13. Like in FIG. 7A, some flow paths are not subjected to the heated storage fluid, including fluid lines L10, L13, L17, L18. To heat disinfect these fluid lines, further recirculation paths may be defined. It may be desirable to fluidly separate the auxiliary fluid system 200b from the main fluid system 200a during the heat disinfection. The auxiliary fluid system 200b is, via the spent dialysis fluid, exposed to a larger microbial load than the main fluid system 200a. It may therefore be undesirable to pump fluid from the auxiliary fluid system 200b into the main fluid system 200a, even during heat disinfection. In FIG. 7B, to heat disinfect the auxiliary fluid system 200b, the valves V17-V19 are set to define a recirculation path that includes the heat exchanger 121. The fluid pump FP4 is operated to circulate storage fluid along the recirculation path while heated storage fluid is circulated in the main fluid system 200a, so that heat is transferred to the auxiliary fluid system 200b via the heat exchanger 121. In an alternative embodiment, not shown, a separate electrical heater is installed in the auxiliary fluid system 200b. It is believed that the use of a heat exchanger 121 reduces cost and complexity of the mixing machine.

[0116] FIG. 8A shows the water machine of FIG. 4A during an in-storage operation according to an embodiment of steps S11-S13. Like in FIG. 7A, the PFP 102 and the RO unit 109 have been replaced with a respective bypass device 102a, 109a. The valves V1-V7 are set to define a recirculation path that includes a plurality of UV generators 106, 107, 111. The fluid pump FP1 is operated to circulate the storage fluid along the recirculation path while the UV generators 106, 107, 111 are activated to emit UV radiation. The activation of the UV generators 107, 111 will disinfect the passing storage fluid, and the activation of UV generator 106 will disinfect the exposed walls of the tank 104. During the in-storage operation, the port 104d on the tank 104 may be closed to the surrounding atmosphere, for example by an on / off valve (not shown), to prevent potential ingress of microorganisms into the tank 104. The UV generator 106 is optional but may improve the microbial status of the water machine after the in-storage operation. Any number of UV generators with any placement may be used. Some flow paths are not included in the recirculation path, including fluid lines L4, L7. To disinfect the storage fluid in these fluid lines, further recirculation paths may be defined, as described with reference to FIG. 7 A.

[0117] FIG. 8B shows the mixing machine of FIG. 4B during an in-storage operation according to an embodiment of steps S11-S13. Like in FIG. 7B, the ultrafilter 120 has been replaced with a bypass device 120a. The valves V8-V16 are set to define a recirculation path that includes a plurality of UV generators 125, 131. The fluid pumps FP2, FP3 are operated to circulate the storage fluid along the recirculation path while the UV generators 125, 131 are activated to emit UV radiation. The activation of the UV generator 131 will disinfect the passing storage fluid, and the activation of UV generator 125 will disinfect the exposed walls of the heating chamber 123. During the in-storage operation, VI 1 may be closed to prevent potential ingress of microorganisms. The UV generator 125 is optional but may improve the microbial status of the mixing machine after the in- storage operation. Any number of UV generators with any placement may be used. Like in FIG. 7A, some flow paths are not subjected to the heated storage fluid, including fluid lines LIO, L13, L17, L18. To disinfect the storage fluid in these fluid lines, further recirculation paths may be defined.

[0118] As shown in FIG. 8B, the in-storage operation may also be performed for the auxiliary fluid system 200b. To this end, the valves V17-V19 are set to define a recirculation path that includes the UV generator 132. The fluid pump FP4 is operated to circulate storage fluid along the recirculation path while the UV generator 132 is activated to emit UV radiation.

[0119] FIG. 9 shows a variant of a mixing machine during heat disinfection. The mixing machine in FIG. 9 differs from the mixing machine in FIG. 4B in that fluid lines L17, LI 8, L22 and valve V16 are removed. A fluid line L23 is added to extend between L12 and L21 via an on / off valve V20. A fluid line L24 is added to extend between V8 in L8 and a 3-way valve V21 in L21. By this change, the main and auxiliary fluid systems 200a, 200b may be jointly heat disinfected, if desired. The recirculation path shown in FIG. 9 presumes that the flow rate generated by FP2 exceeds the flow rate generated by FP4. A similar recirculation path may be used to disinfect the storage fluid by activation of the UV generators 125, 132.

[0120] It is conceivable that some of the storage fluid may escape from the mixing machine during storage, for example a result of transport of vapor through tubings or connectors or release of vapor from the heating chamber 123, especially during heat disinfection. This may cause the amount of storage fluid in the mixing machine to decrease over time. If the mixing machine is placed in storage for a long time and / or if the mixing machine is heat disinfected during storage, the amount of storage fluid may decrease to such an extent that disinfection by UV radiation is rendered ineffective. FIG. 10 shows an arrangement for refilling fluid into the mixing machine during storage. In FIG. 10, the mixing machine is provided with an additional port P9, which is exposed on the chassis 13'. A fluid line LI 1' extends from the port P9 to the heating chamber 123 via an on / off valve VI 1'. A container WB with storage fluid is provided. In this example, the container WB may hold product water. A connection line CL9 extends from the container WB to a terminal connector C9. The container WB is fluidly connected to the port P9 via the connector C9. The control device of the mixing machine may be configured to, during storage, ensure that the mixing machine contains an adequate amount of storage fluid. To this end, the control device may monitor the fluid level in the heating chamber 123 based on the signal S3 from the level sensor 126. If the fluid level falls below a predefined first level, the control device may open the valve VI 1' to admit storage fluid from the container WB into the heating chamber 123 until the fluid level reaches a predefined second level above the predefined first level. In the illustrated example, the refilling operation is performed during heat disinfection, but it may be performed at any time during storage. One advantage of performing the refill operation during heat disinfection is that the incoming storage fluid from the container WB will be automatically heat disinfected. It is to be noted that the fluid line LI 1' need not extend to the heating chamber 123 by may be connected to the main fluid system 200a at any location.

[0121] The water machine in FIG. 4A may be modified in correspondence with FIG. 10 to enable the refill operation. A lack of storage fluid may be detected based on the signal SI from the level sensor 105 of the tank 104.

[0122] In the examples of FIGS 7-9, ports are included in the one or more recirculation paths that are established during disinfection. In other words, the storage fluid is directed through the respective port. This will minimize the risk of microbial growth as a result of stagnant storage fluid in the ports. In the example of FIGS 7-9, all ports except the drain port P3 are included in a recirculation path. This is a matter of choice, and the configuration of the water machine may be modified to include also the drain port in a recirculation path.

[0123] There are many ways of including a port in a recirculation path. A non-limiting example is shown in FIGS 11A-1 IB, which are section views of the port P5 as installed in the mixing machine. FIG. 11 A depicts a connected state, in which the port P5 is connected to the terminal connector C5 on the connecting line CL5 (FIG. 5). FIG. 1 IB depicts a disconnected state, in which the port P5 is closed off and thus disconnected from the connecting line CL5. The port P5 comprises a main body 70 and a lid or cap 71, which is joined to the main body 70 for rotation around a hinge 72. The main body 70 defines a cavity or hole 73. The cavity 73 defines an opening for receiving the connector C5. In the machine (FIG. 4B), fluid lines L12, L14 extends to / from the port P5. As seen in FIGS 11A-1 IB, both fluid lines L12, L14 open into the internal cavity 73. In the connected state (FIG. 11A), the lid 71 is swung away from the main body 70 to expose the opening to the cavity 73, and the connector C5 is engaged with the opening. Thereby, CL5 is in fluid communication with L12, L14 via the cavity 73. In the disconnected state (FIG. 1 IB), the lid 71 is swung into contact with the main body 70 so that a recess 74 in the lid 71 mates with the opening to the cavity 73. The cavity 73 and the recess 74 thereby defines an internal chamber, which is closed to the surroundings and directs incoming fluid to pass from L12 to L14, and vice versa. The lid 71 may be biased towards the main body 70, so that the port P5 is automatically brought into the state in FIG. 1 IB when the connector C5 is disengaged from the cavity 73.

[0124] All ports in the water machine and the mixing machine may be configured in correspondence with FIGS 11A-11B.

[0125] FIG. 12 is a block diagram of an example control arrangement 80, which may be configured to control the operation of any machine as described herein. The control arrangement 80 may thus correspond to the control device 28 in FIG. 2A. The functionality of the control device 80 may be defined by a combination of software and hardware circuitry, or exclusively by specific hardware circuitry. In FIG. 12, the control arrangement 80 comprises processor circuitry 81, which may be or include a central processing unit (CPU), graphics processing unit (GPU), microcontroller, microprocessor, ASIC, FPGA, or any other specific or general processing device. The control arrangement 80 may operate by executing instructions stored in a computer memory, such as memory 82. The instructions when executed by the processor circuitry 81 may cause the control arrangement 80 to perform any of the methods, procedures and functions described herein, or part thereof. The memory 82 may comprise one or more of a buffer, flash memory, hard drive, removable media, volatile memory, nonvolatile memory, random access memory (RAM), or another suitable data storage device. Such a memory 82 is considered a non-transitory computer readable medium. The instructions may be supplied to the control arrangement 80 on a computer-readable medium, which may be a tangible (non-transitory) product (e.g., magnetic medium, optical disk, read-only memory, flash memory, etc.) or a propagating signal. The control arrangement 80 includes an I / O interface 83a, which may include any conventional communication interface for wired or wireless communication. As shown, the control arrangement 80 is arranged to receive input signals SSi and to output control signals CSj. For example, the input signals may include any one of signals S1-S5 described with reference to FIGS 4A-4B. The control signals may be provided to valves, fluid pumps, heaters, UV generators, etc., in the respective machine. The control arrangement 80 may comprise a further interface 83b for connection to a feedback device 84 for user interaction. The feedback device 84 defines a user interface and may include one or more of a display, a touch screen, a speaker, one or more signaling lamps, one or more control buttons, a keyboard / keypad, a microphone, a computer mouse, a projector, a camera, etc.

[0126] Although the foregoing examples have been directed to production of dialysis fluid, the technique presented herein is generally applicable to any machine that is operable to generate any type of medical fluid. Examples include machines for generating medical fluids for infusion into the circulatory system of a human or animal individual. These machines may also include an infusion pump for administering the medical fluid to the individual. Such medical fluids include IV (intravenous) solutions. Non-limiting examples of IV solutions include sodium chloride solution 0.9 w / v%, glucose 5% w / v solution, Ringer's solution, Hartman's solution, antibiotics, anticancer drugs, etc. The presented technique is likewise applicable to machines for generating medical fluids for intramuscular or subcutaneous administration.

[0127] While the subject of the present disclosure has been described in connection with what is presently considered to be the most practical embodiments, it is to be understood that the subject of the present disclosure is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.

[0128] Further, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results.

[0129] In the following, clauses are recited to summarize some aspects and embodiments as disclosed in the foregoing.

[0130] Cl. A method of operating a machine (20) configured for generation of a medical fluid, said machine (20) comprising: an inlet connector (21a) for releasable connection to a source of a first fluid, a fluid processing device (25) for processing the first fluid into a second fluid, which is comprised in the medical fluid, and an outlet connector (22a) for releasable connection to a receiving device for receiving the second fluid, wherein the fluid processing device (25) comprises a fluid path system (200) in fluid communication with the inlet and outlet connectors (21a, 22a), and one or more fluid pumps (26a-26c) arranged in the fluid path system (200), said method comprising: preparing (S10) the machine (20) for storage, in which the machine is inoperable to generate the second fluid, by operating (SlOa) the machine to fill the fluid path system (200) with a storage fluid; operating (Si l), during the storage, the fluid processing device (25) to define, in the fluid path system (200), one or more recirculation paths (la-lc) that include the one or more fluid pumps (26a-26c); and operating (S12), during the storage, the one or more fluid pumps (26a-26c) to displace the storage fluid along the one or more recirculation paths (la-lc).

[0131] C2. The method of Cl, wherein the one or more recirculation paths (la-lc), for a respective fluid pump among the one or more fluid pumps (26a-26c), define a flow path from an outlet of the respective fluid pump to an inlet of the respective fluid pump. C3. The method of C2, wherein the one or more fluid pumps include all fluid pumps in the fluid processing device (25) that are used for processing the first fluid into a second fluid.

[0132] C4. The method of any preceding clause, wherein said preparing (S10) the machine further comprises: causing (SlOc) an operator to disconnect the inlet connector (21a) from the source and / or to disconnect the outlet connector (22a) from the receiving device.

[0133] C5. The method of C4, wherein the fluid processing device (24) further comprises a heating device (27a) in the fluid path system (200), and wherein said preparing (S10) the machine further comprises: jointly operating (SlOb) the heating device (27a) and at least one of the one or more fluid pumps (26a-26c) to perform a heat treatment of at least part of the fluid path system (200).

[0134] C6. The method of C4 or C5, wherein the machine (20) comprises a local power source (30) and a mains connector (40) for electrical connection to a mains power outlet (41), wherein said preparing (S10) the machine further comprises: causing (SlOd) the machine (20) to switch from obtaining electrical power from the mains connector (40) to obtaining the electrical power from the local power source (30).

[0135] C7. The method of any preceding clause, wherein the fluid processing device (25) comprises a disinfection arrangement (27) in the fluid path system (200), wherein the one or more recirculation paths (la-lc) are defined to include the disinfection arrangement (27), said method further comprising: operating (S13), during the storage, the disinfection arrangement (27) to process the storage fluid for disinfection while the one or more fluid pumps (26a-26c) displace the storage fluid along the one or more recirculation paths (la-lc) and through the disinfection arrangement (27).

[0136] C8. The method of C7, wherein the disinfection arrangement (27) comprises an irradiation device (27b) which is operable to emit ultraviolet radiation, wherein said operating (S13) the disinfection arrangement (27) during the storage comprises: operating the irradiation device (27b) to emit the ultraviolet radiation onto the storage fluid while the one or more fluid pumps (26a-26c) displace the storage fluid along the one or more recirculation paths (la-lc) and through the irradiation device (27a).

[0137] C9. The method of C5, wherein the one or more recirculation paths (la-lc) are defined to include the heating device (27a), said method further comprising: operating (S13), during the storage, the heating device (27a) to heat the storage fluid to a disinfection temperature while the one or more fluid pumps (26a-26c) displace the storage fluid along the one or more recirculation paths (la-lc).

[0138] CIO. The method of any preceding clause, wherein the one or more recirculation paths (la-lc) are defined to include all parts of the fluid path system (200). Cl 1. The method of clause 10, wherein the one or more recirculation paths (laic) are defined to include the inlet and outlet connectors (21a, 22a), and fluid paths (21, 22) between the fluid path system (200) and the inlet and outlet connectors (21a, 22a).

[0139] C12. The method of any preceding clause, wherein the one or more fluid pumps (26a-26c) are operated to displace the storage fluid along the one or more recirculation paths (la-lc) at least once every 24 or 48 hours during the storage.

[0140] C13. The method of any preceding clause, wherein the machine comprises an inlet (P9) for additional storage fluid from an external source (WB), wherein the method further comprises, during the storage, obtaining a signal indicative of the amount of storage fluid in the fluid path system (200), and selectively opening a fluid passage between the inlet (P9) and the fluid path system (200), based on the signal, to admit the additional storage fluid into the fluid path system (200).

[0141] C14. The method of C13, wherein the signal is obtained from a level sensor arranged to measure a level of storage fluid in a chamber (123) in fluid communication with the fluid path system (200).

[0142] C15. The method of any preceding clause, wherein the medical fluid is a treatment fluid for use in dialysis therapy.

[0143] Cl 6. The method of any preceding clause, wherein the first fluid is water.

[0144] C17. The method of C16, wherein the second fluid is product water with a higher purity than said water.

[0145] Cl 8. The method of any one of Cl -Cl 6, wherein the second fluid is the medical fluid.

[0146] C19. The method of any one of C1-C15, wherein fluid processing device (25) is configured to purify the first fluid, or mix the first fluid or the second fluid with one or more concentrates to generate the medical fluid.

[0147] C20. The method of any preceding clause, wherein the storage fluid comprises at least one of the first fluid or the second fluid.

[0148] C21. The method of any one of Cl -Cl 8, wherein the storage fluid is a concentrate that is used by the fluid processing device (25) to generate the medical fluid.

[0149] C22. The method of C21, wherein the concentrate is bacteriostatic.

[0150] C23. The method of any preceding clause, wherein the machine is configured to generate the medical fluid at a first location and to be moved into storage at a facility that is separated from the first location.

[0151] C24. A computer-readable medium comprising computer instructions which, when executed by processing circuitry, cause the processing circuitry to perform the method of any one of C1-C23. C24. A machine configured for generation of a medical fluid, said machine comprising: an inlet connector (21a) for releasable connection to a source of a first fluid; a fluid processing device (25) for processing the first fluid into a second fluid, which is comprised in the medical fluid; an outlet connector (22a) for releasable connection to a device for receiving the second fluid; and a control device (28) for operating the fluid processing device (25), wherein the fluid processing device (25) comprises a fluid path system (200) in fluid communication with the inlet and outlet connectors (21a, 22a), and one or more fluid pumps (26a-26c) arranged in the fluid path system (200), wherein the control device (28) is configured to: operate (SlOa) the machine to fill the fluid path system (200) with a storage fluid to prepare the machine for storage, in which the machine is inoperable to generate the second fluid; operate (Si l), during the storage, the fluid processing device (25) to define, in the fluid path system (200), one or more recirculation paths (la-lc) that include the one or more fluid pumps (26a-26c); and operate (S12), during the storage, the one or more fluid pumps (26a-26c) to displace the storage fluid along the one or more recirculation paths (la-lc).

Claims

32CLAIMS1. A method of operating a machine (20) configured for generation of a medical fluid, said machine (20) comprising: an inlet connector (21a) for releasable connection to a source of a first fluid, a fluid processing device (25) for processing the first fluid into a second fluid, which is comprised in the medical fluid, and an outlet connector (22a) for releasable connection to a receiving device for receiving the second fluid, wherein the fluid processing device (25) comprises a fluid path system (200) in fluid communication with the inlet and outlet connectors (21a, 22a), and one or more fluid pumps (26a-26c) arranged in the fluid path system (200), said method comprising: preparing (S10) the machine (20) for storage, in which the machine is inoperable to generate the second fluid, by operating (SlOa) the machine to fill the fluid path system (200) with a storage fluid, operating (Si l), during the storage, the fluid processing device (25) to define, in the fluid path system (200), one or more recirculation paths (la-lc) that include the one or more fluid pumps (26a-26c), and operating (S12), during the storage, the one or more fluid pumps (26a-26c) to displace the storage fluid along the one or more recirculation paths (la-lc).

2. The method of claim 1, wherein the one or more recirculation paths (la-lc), for a respective fluid pump among the one or more fluid pumps (26a-26c), define a flow path from an outlet of the respective fluid pump to an inlet of the respective fluid pump.

3. The method of claim 2, wherein the one or more fluid pumps include all fluid pumps in the fluid processing device (25) that are used for processing the first fluid into a second fluid.

4. The method of any preceding claim, wherein said preparing (S10) the machine further comprises: causing (SlOc) an operator to disconnect the inlet connector (21a) from the source and / or to disconnect the outlet connector (22a) from the receiving device.

5. The method of claim 4, wherein the fluid processing device (24) further comprises a heating device (27a) in the fluid path system (200), and wherein said preparing (S10) the machine further comprises: jointly operating (SlOb) the heating33 device (27a) and at least one of the one or more fluid pumps (26a-26c) to perform a heat treatment of at least part of the fluid path system (200).

6. The method of claim 4 or 5, wherein the machine (20) comprises a local power source (30) and a mains connector (40) for electrical connection to a mains power outlet (41), wherein said preparing (S10) the machine further comprises: causing (SlOd) the machine (20) to switch from obtaining electrical power from the mains connector (40) to obtaining the electrical power from the local power source (30).

7. The method of any preceding claim, wherein the fluid processing device (25) comprises a disinfection arrangement (27) in the fluid path system (200), wherein the one or more recirculation paths (la-lc) are defined to include the disinfection arrangement (27), said method further comprising: operating (S13), during the storage, the disinfection arrangement (27) to process the storage fluid for disinfection while the one or more fluid pumps (26a-26c) displace the storage fluid along the one or more recirculation paths (la-lc) and through the disinfection arrangement (27).

8. The method of claim 7, wherein the disinfection arrangement (27) comprises an irradiation device (27b) which is operable to emit ultraviolet radiation, wherein said operating (S13) the disinfection arrangement (27) during the storage comprises: operating the irradiation device (27b) to emit the ultraviolet radiation onto the storage fluid while the one or more fluid pumps (26a-26c) displace the storage fluid along the one or more recirculation paths (la-lc) and through the irradiation device (27a).

9. The method of claim 5, wherein the one or more recirculation paths (la-lc) are defined to include the heating device (27a), said method further comprising: operating (S13), during the storage, the heating device (27a) to heat the storage fluid to a disinfection temperature while the one or more fluid pumps (26a-26c) displace the storage fluid along the one or more recirculation paths (la-lc).

10. The method of any preceding claim, wherein the one or more recirculation paths (la-lc) are defined to include all parts of the fluid path system (200).

11. The method of claim 10, wherein the one or more recirculation paths (la-lc) are defined to include the inlet and outlet connectors (21a, 22a), and fluid paths (21, 22) between the fluid path system (200) and the inlet and outlet connectors (21a, 22a).

12. The method of any preceding claim, wherein the one or more fluid pumps (26a-26c) are operated to displace the storage fluid along the one or more recirculation paths (la-lc) at least once every 24 or 48 hours during the storage.

13. The method of any preceding claim, wherein the machine comprises an inlet (P9) for additional storage fluid from an external source (WB), wherein the method further comprises, during the storage, obtaining a signal indicative of the amount of storage fluid in the fluid path system (200), and selectively opening a fluid passage between the inlet (P9) and the fluid path system (200), based on the signal, to admit the additional storage fluid into the fluid path system (200).

14. The method of claim 13, wherein the signal is obtained from a level sensor arranged to measure a level of storage fluid in a chamber (123) in fluid communication with the fluid path system (200).

15. The method of any preceding claim, wherein the medical fluid is a treatment fluid for use in dialysis therapy.

16. The method of any preceding claim, wherein the first fluid is water.

17. The method of claim 16, wherein the second fluid is product water with a higher purity than said water.

18. The method of any one of claims 1-16, wherein the second fluid is the medical fluid.

19. The method of any one of claims 1-15, wherein fluid processing device (25) is configured to purify the first fluid, or mix the first fluid or the second fluid with one or more concentrates to generate the medical fluid.

20. The method of any preceding claim, wherein the storage fluid comprises at least one of the first fluid or the second fluid.

21. The method of any one of claims 1-18, wherein the storage fluid is a concentrate that is used by the fluid processing device (25) to generate the medical fluid.

22. The method of claims 21, wherein the concentrate is bacteriostatic.

23. The method of any preceding claim, wherein the machine is configured to generate the medical fluid at a first location, and to be moved into storage at a facility that is separated from the first location.

24. A computer-readable medium comprising computer instructions which, when executed by processing circuitry, cause the processing circuitry to perform the method of any one of claims 1-23.

25. A machine configured for generation of a medical fluid, said machine comprising: an inlet connector (21a) for releasable connection to a source of a first fluid, a fluid processing device (25) for processing the first fluid into a second fluid, which is comprised in the medical fluid, an outlet connector (22a) for releasable connection to a device for receiving the second fluid, and a control device (28) for operating the fluid processing device (25), wherein the fluid processing device (25) comprises a fluid path system (200) in fluid communication with the inlet and outlet connectors (21a, 22a), and one or more fluid pumps (26a-26c) arranged in the fluid path system (200), wherein the control device (28) is configured to: operate (SlOa) the machine to fill the fluid path system (200) with a storage fluid to prepare the machine for storage, in which the machine is inoperable to generate the second fluid, operate (Si l), during the storage, the fluid processing device (25) to define, in the fluid path system (200), one or more recirculation paths (la-lc) that include the one or more fluid pumps (26a-26c), and operate (S12), during the storage, the one or more fluid pumps (26a-26c) to displace the storage fluid along the one or more recirculation paths (la-lc).

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