System and method for providing highly purified water, and laboratory comprising such system

Abstract

The present application relates to a water purification system capable of providing ultrapure water for laboratory applications, comprising at least one water connection for supplying the system with feed water, for example tap water, to be purified, at least one pre-purification unit for pre-purifying the tap water, and at least one post-purification unit for post-purifying the pre-purified water. Furthermore, the present application relates to a laboratory comprising such water purification system. In addition, the present application relates to a method of producing purified water, particularly ultrapure water.

Description

[0001] SYSTEM AND METHOD FOR PROVIDING HIGHLY PURIFIED WATER, AND LABORATORY COMPRISING SUCH SYSTEM

[0002] Technical Field

[0003] The present application relates to a water purification system capable of providing ultrapure water for laboratory applications, comprising at least one water connection for supplying the system with feed water, for example tap water, to be purified, at least one pre-purification unit for pre-purifying the tap water, and at least one post-purification unit for post-purifying the pre-purified water. Furthermore, the present application relates to a laboratory comprising such a water purification system. In addition, the present application relates to a method of producing purified water, particularly ultrapure water, and / or for operating said system, in particular in such a laboratory.

[0004] Background

[0005] Many applications require water having a purity higher than natural water or tap water and therefore frequently use ultrapure water. Ultrapure water can be defined as the highest quality reagent grade water (ASTM D5127) that exceeds ASTM D1193 type I standards and has a specific resistance of more than 18.0 MQ • cm at 25°C and a total organic carbon (TOC) content of at most five parts per billion (< 5 ppb).

[0006] Water purification systems providing purified water, in particular ultrapure water, in a desired volume from feed water, such as tap water, and allowing the purified water to be withdrawn and dispensed are known already. Such water purification systems may be used in laboratories, in particular in biological, chemical, or analytical laboratories. These water purification systems generally comprise, in sequence, a pre-purification or pretreatment unit, a storage tank, and a post-purification or polishing unit. In the prepurification unit, the feed water is frequently purified through a reverse osmosis unit, optionally in combination with an electrodeionization unit. However, due to reverse osmosis and electrodeionization units having to be run continuously and with overall demand for purified water in a laboratory environment being rather low, these water purification systems are designed to have a low production capacity, for example in the range from a few liters per hour to about 30 liters per hour, and are therefore ill-suited to cope with peaks in demand. With the post-purification unit for providing ultrapure water being designed for and capable of much higher throughputs, current water purification systems for laboratory application typically require the use of an intermediate storage tank to make up for this disadvantage.

[0007] In current water purification systems for laboratory applications, the pre-purification unit, the storage tank, and the post-purification unit are inseparably installed side-by-side near a water source. Due to their significant footprint, it may not be desirable or not even feasible to install such water purification systems on or under every workbench. Laboratory personnel are therefore forced to either work in close proximity to such a water purification system or to fill a carboy or bottle with the ultrapure water and carry it to their respective working stations. However, it is rather difficult if not impossible to assure that the carboys or bottles used to hold and transport the ultrapure water are sufficiently clean and free of contaminants to guarantee maintaining water purity. The same problems would arise if sufficiently long tubing were to be used to conduct the ultrapure water from the water purification system to one or more than one point(s) of use, such as one or more workstation(s) or work bench(es) in a laboratory. Furthermore, ultrapure water and even ASTM-D1193 Type II water quickly deteriorates in quality. Particularly, any handling and storing under ambient atmosphere easily introduces airborne contaminants. Hence, only freshly produced ultrapure water can be reliably considered compliant with the requirements of the respective norms.

[0008] An example of a prior art water treatment system is disclosed in CA 2477939 Al. This "under-sink" water treatment system includes a viral filter membrane, a storage tank, and a bacterial filter membrane affixed side-by-side (e.g. under the sink) to purify the supply water prior to it being dispensed by the sink's faucet. The storage tank is disposed between the filters to buffer the upstream filter's relatively low flow rate so as to improve the flow capacity of the system, but is bypassed if the storage tank is empty when the faucet is turned on. The storage tank is not mobile during operation of the system, nor would the tank prevent spillage or contamination of the water contained therein when disconnected.

[0009] US 6,099,735 Bl similarly describes a water purification system for placement on the countertop in which multiple purification units and a storage tank are integrated within a single fluid treatment circuit coupled to a water supply.

[0010] Consequently, to assure a high level of reproducibility of the laboratory's results and to exclude errors due to contaminants in the water used, current water purification systems require every workstation or work zone in such a laboratory to be equipped with its own system, resulting in valuable and expensive lab area being taken up by water purification units.

[0011] Furthermore, the current water purification systems for laboratory applications are specifically designed for the production of ultrapure water, i.e. water of the highest purity. However, even in a laboratory, not all uses might require ultrapure water. It would therefore be desirable to have a water purification system allowing for simultaneous production of purified water of different levels of purity without requiring additional equipment and thus footprint in the laboratory or even on the work benches.

[0012] The components for purifying water to the desired purity level are known as such. An integral water purification system that is designed to purify water from e.g. tap water comprises various water purification means like pre-filtration means (for example, sediment filters or activated carbon filters), reverse osmosis units, electrodeionization units, ion exchangers, and UV radiation treatment means, either singly or in any combination. In order to achieve the purification of tap water to the ultrapure water grade, current systems typically comprise a first purification ("pre-purification") stage that is arranged to purify the water from tap grade to a first purity grade like ASTM D1193 type II or lower and a second water purification ("post-purification") stage that is arranged to purify the pre-purified water further to a second purity grade that is typically higher than the first purity grade, preferably a type I or ultrapure water grade.

[0013] Water purification to the ultrapure level is a challenge. Therefore, the first purification stage shall be inter alia properly rinsed to avoid contaminants to pass to the second purification stage, in order to not affect purification in the second purification stage and to ensure desired water quality. The flow rates through the first water purification stage are typically small compared to the second water purification stage, so that as indicated above purified water is generally temporarily stored in a water tank, which allows for dispensing purified water at a higher flow rate depending on demand.

[0014] In the post-purification unit, further contaminants may then be removed from the prepurified water, for example by means of an ion exchanger, activated carbon filter and / or UV irradiation. Intermediate storage of the post-purified water in a water tank can be omitted if the throughput of the post-purification unit is adapted to the maximum volume flow rate to be discharged. For dispensing the post-purified water, i.e. the ultrapure water, a dispenser is connected to the post-purification unit, which can be operated manually depending on the application. Hence, supplying larger laboratories having a number of workplaces requiring ultrapure water involves a not inconsiderable amount of work and investment, not least because of the process steps required to provide ultrapure water. Furthermore, current water purification systems are not flexible enough to satisfy all requirements occurring in a biological, chemical, or analytical laboratory. This makes supplying laboratories with ultrapure water cost- and maintenance-intensive.

[0015] There is therefore a need for improving the presently available water purification systems for providing purified water, particularly ultrapure water, for laboratory application.

[0016] Consequently, the present application aims at providing an improved water purification system for laboratory applications that is characterized by one or more of allowing for higher flexibility in placement of the respective system components, additional flexibility in providing different purified water levels from essentially the same water purification system, and having an overall reduced system footprint, while allowing to continuously and reproducibly provide water of the required water quality, for example ultrapure water, at every workstation, in such a way that the provision of ultrapure water in laboratories can be carried out more simply and more economically, while still ensuring consistent quality of the purified water provided by such a water purification system.

[0017] Additionally, it is an object of the present application to provide for a water purification system for laboratory application that can more easily than existing systems be adapted to changing requirements in a laboratory.

[0018] Summary

[0019] The above objects are attained either singly or in any combination by the present water purification system, the present laboratory, and the present method for producing purified water.

[0020] Thus, the present application provides for a system for providing ultrapure water for laboratory applications, comprising at least one water connection for supplying the system with feed water to be purified, at least one pre-purification unit fixedly connected to the at least one water connection for pre-purifying the feed water to produce prepurified water, at least one post-purification unit for post-purifying the pre-purified water to produce post-purified water, and at least one water tank, said system being characterized in that the at least one pre-purification unit is fixedly connected to a prepurification adapter, the pre-purification adapter for detachably connecting a water tank for receiving the pre-purified water from the pre-purification unit, and the at least one post-purification unit is fixedly connected to a post-purification adapter, the postpurification adapter for detachably connecting a water tank for supplying the pre-purified water to the at least one post-purification unit, and in that the pre-purification adapter and the post-purification adapter are similarly configured for sequentially connecting with one and the same water tank, preferably wherein the feed water is tap water.

[0021] The present application further provides for a laboratory comprising at least one such system, preferably a laboratory comprising at least one such system, characterized in that the laboratory comprises more post-purification units than pre-purification units, preferably at least twice as many post-purification units than pre-purification units, further preferably at least three times as many post-purification units than prepurification units, in particular four times as many post-purification units than prepurification units, and in that, preferably, the post-purification units are arranged at different laboratory workplaces, in particular on different laboratory benches.

[0022] Additionally, the present application provides for a method of operating such a system, in particular in a laboratory as described above, wherein feed water is supplied via the water connection to the at least one pre-purification unit(s) and is pre-purified in the prepurification unit(s) to produce pre-purified water, wherein the pre-purified water is fed into a water tank via a pre-purification adapter, wherein the water tank, at least partially filled with pre-purified water, is separated from the pre-purification adapter, moved manually to the post-purification adapter and connected to the post-purification adapter, wherein the pre-purified water is fed from the water tank to the post-purification unit via the post-purification adapter and is post-purified in the post-purification unit to produce post-purified water, and optionally wherein the post-purified water is dispensed via a dispenser fixedly connected to the post-purification unit.

[0023] Detailed description

[0024] It is noted that though the description may refer to tap water as the feed water it will be understood by the skilled person that other water sources may also be used as feed water. For the purpose of the present application, the term "connect", "connected", and "connection" and conjugated or declinated versions thereof are used to denote "liquid tightly connect", "liquid tightly connected", and "liquid tight connection", thereby also indicating that through such connection a liquid, such as water, is to pass through.

[0025] For the purpose of the present application, the term "spatially separated" is used to denote that the respective components, systems, devices, units, or similar are some distance apart, for example 1 m or 5 m or 10 m or more, or may be placed in different rooms, on different floors etc., and in any case that these are not physically, particularly not fluidly, connected.

[0026] For the purpose of the present application, the term "lumen" is used to denote a continuous cavity extending along the longitudinal axis of a tubing. Throughout this application, such continuous cavity extending along the longitudinal axis of a tubing may also be referred to as "flow path" or "channel".

[0027] In general terms, the present water purification system comprises a pre-purification unit, a pre-purification adapter, a post-purification unit, a post-purification adapter, and a portable water tank.

[0028] For the pre-purification of the feed water, for example tap water, it is suitable for the prepurification unit of the present water purification system to comprise one or more selected from the group consisting of a reverse osmosis unit with at least one semi- permeable membrane, an electrodeionization unit with at least two electrodes, an activated carbon unit with at least one activated carbon, in particular an activated carbon filter, an ion exchange unit with at least one ion exchanger resin, a filtration unit, such as a pleated filtration unit or a depth filtration unit with at least one depth filter, and any combination of these. It is, however, preferred that the pre-purification comprises one or more selected from the group consisting of a reverse osmosis unit, an activated carbon unit with at least one activated carbon, an ion exchanger with at least one ion exchanger resin, a filtration unit, such as a pleated filtration unit or a depth filtration unit with at least one depth filter, and any combination of these. It is even more preferred that the present pre-purification unit comprises one or more selected from the group consisting of a reverse osmosis unit, an activated carbon unit, a filtration unit, such as a pleated filtration unit or a depth filtration unit with at least one depth filter, and any combination of these. Alternatively, if feed water quality allows, pre-purification may be done with a reverse osmosis unit only, i.e. the pre-purification unit comprises a reverse osmosis unit as the only purifying means. In reverse osmosis, particles and ions are retained as the water passes through the semipermeable membrane. Activated carbon can be used to adsorb organic compounds or free chlorine, for example. The water can flow through the activated carbon in the sense of a filter or pass through it in the sense of an adsorbent. An ion exchange resin can be provided in an ion exchange unit, which accumulates ions from the water and releases ions in return, for example OH- and H+(respectively H3O+). Generally such an ion exchange unit comprises a mixture of anionic and cationic ion exchange resins, for example a so-called mixed-bed ion exchange resin. Suitable ion exchange resins are generally known to the skilled person. For depth filtration, a filter medium is used to separate particles in the depth of the filter medium.

[0029] Independently of the pre-purification unit, the post-purification unit of the present water purification system can comprise one or more selected from the group consisting of an ion exchanger unit with at least one ion exchanger resin for separating ions, at least one activated carbon unit with at least one activated carbon for separating organic components, at least one UV unit with at least one UV lamp, which is operated at a wavelength of below 200 nm, for photo-oxidation of, for example, organic compounds, bacteria, viruses and germs, or any combination of these units. In this way, the purity of the pre-purified water can once again be significantly improved. Which purification principles are suitably applied in the pre-purification unit and the post-purification unit will depend in particular on the requirements for water quality and / or the quality of the feed water. For example, the post-purification unit may comprise at least one ion exchanger but no activated carbon unit and / or no UV unit. Or the post-purification unit may comprise at least one ion exchanger and at least one activated carbon unit but no UV unit. In other words, the post-purification unit may comprise at least one ion exchanger and at least one activated carbon as the only purifying means.

[0030] In some cases, it is also useful if the pre-purification of the water is carried out in at least two sub-stages. For example, the pre-purification unit can comprise a first purification sub-unit and a second purification sub-unit. If the second purification sub-unit is formed, for example, by a reverse osmosis unit for purifying the water by way of reverse osmosis or by an electrodeionization unit, it may be expedient, in order to protect the second purification sub-unit of the pre-purification unit, if the first purification sub-unit provides an activated carbon, in particular an activated carbon filter, an ion exchanger and / or a depth filter. As described herein, the present water purification system allows for the pre-purification unit with the pre-purification adapter on the one hand side and the post-purification unit with the post-purification adapter on the other hand side to be spatially separated from each other. The pre-purification unit can therefore be provided at one location in the laboratory, for example in the vicinity of a feed water supply, for example a water faucet or tap, while the post-purification unit may be provided at a spatially separated, different location, for example at a workstation in the laboratory that is a distance away from the feed water supply but where the user requires high purity water, for example ultrapure water, for the task to be accomplished. In this way, the present water purification system avoids the need for installing a conventional water purification system (i.e. a water purification system comprising a pre-purification unit, a storage tank and a postpurification unit in an inseparable side-by-side configuration) and thereby leads to a significant reduction in the space required to provide the purified water at the workstation(s) or work bench(es). The pre-purification unit of the present water purification system can be installed where space and a feed water stream (such as a water faucet or tap or the like) are already available anyway.

[0031] To ensure that the water pre-purified in the pre-purification unit can easily be supplied to the post-purification unit without the risk of unwanted contamination, the prepurification unit is fixedly connected to a pre-purification adapter and the postpurification unit is fixedly connected to a post-purification adapter, wherein the prepurification adapter and the post-purification adapter can sequentially be connected to one and the same portable water tank (i.e. the storage tank is first connected to the prepurification adapter to be filled, then removed from there, moved to the post-purification adapter and connected thereto). In other words, at any given time a specific water tank can be detachably mounted to only one of the pre-purification adapter(s) and postpurification adapter(s), but can be detachably mounted independently to each at different times. It is noted that generally the pre-purification adapter is downstream of the prepurification unit, and the post-purification adapter is upstream of the post-purification unit. Water pre-purified in the pre-purification unit can be introduced into the water tank connected to the pre-purification adapter. The water tank can then be disconnected from the pre-purification adapter, manually moved to the post-purification adapter, and connected to the post-purification adapter. The pre-purified water from the water tank connected to the post-purification adapter can then be introduced into the postpurification unit, where it can be post-purified and then dispensed via a dispenser. This allows to have post-purified, particularly ultrapure, water available in a consistent manner whenever needed. In a first particularly preferred embodiment of the system, the pre-purification adapter is provided with a closure which forcibly moves to a closed position when the water tank is disconnected from the pre-purification adapter. The closure remains in the closed position until a water tank, which may be the same or another, is again connected to the pre-purification adapter. In this way, contamination of the pre-purification unit or of the pre-purified water remaining in the pre-purification unit is avoided or at least reduced. In an analogous manner, the post-purification adapter is provided with a closure which forcibly moves to a closed position when the water tank is disconnected from the postpurification adapter. The closure remains in the closed position until a water tank, which may be the same or another, is again connected to the post-purification adapter. In this way, contamination of the post-purification unit or of the pre-purified water remaining in the post-purification unit is avoided. For this purpose, the respective closure may be spring-loaded such that the restoring force of a spring means moves the closure to the closed position. When connected to the water tank, the closure can then be forcibly displaced against the restoring force of the spring means, whereby the closure is forced into an open position in which the pre-purified water is allowed to flow as follows: i) from the pre-purification unit via the pre-purification adapter into the water tank when the water tank is connected to the pre-purification adapter; or ii) from the water tank via the post-purification adapter into the post-purification unit when the water tank is connected to the post-purification adapter.

[0032] Alternatively or additionally, the pre-purification adapter and / or the post-purification adapter can each have a seal for sealing a connection for the flow of pre-purified water when connected to the water tank. In this way, it is not only possible to prevent unwanted leakage from occurring, but also to ensure that contamination of the pre-purified water, the pre-purification unit and / or the post-purification unit is prevented.

[0033] For the purpose of a simple and at the same time reliable and reproducible connection between the water tank on the one hand and the pre-purification adapter and / or the post-purification adapter on the other hand, it can be useful if the pre-purification adapter and the post-purification adapter are provided for attaching a water tank from above onto the pre-purification adapter and the post-purification adapter. The pre-purification adapter and / or the post-purification adapter can be designed in such a way that when the water tank is attached from above, the connection is forced in a position for pre-purified water to flow through. If necessary, a connection piece of the water tank can then be pushed into a receptacle of the pre-purification adapter or the post-purification adapter in a form-fitting manner in such a way that the connection of the pre-purification adapter or the post-purification adapter is adjusted from the closed position to the open position, for example, in particular against the restoring force of the corresponding spring means.

[0034] It is particularly useful if the pre-purification adapter and the post-purification adapter are designed to form a (non-positive and / or positive) connection with the water tank by placing the water tank onto the pre-purification adapter and the post-purification adapter. In this way, the water tank is precisely aligned with the pre-purification adapter and the post-purification adapter and reliably held there. Accidental contamination of the pre-purified water, whether in the pre-purification unit, the water tank and / or the post- purification unit, can thus be prevented.

[0035] Preferably, the present pre-purification adapter(s) and post-purification adapter(s) independently of each other comprise a manifold for a water tank, as described in the following.

[0036] The present manifold comprises a first flow channel for filling and / or draining the water into / from the tank; a second flow channel for guiding the water in the tank to a pressure sensor mounted in the manifold so as to allow a measurement of the static pressure in the water tank; and a third flow channel connecting the first flow channel and the second flow channel, wherein the third flow channel is configured and arranged to replace water stagnant in the second flow channel when water is filled and / or drained into / from the tank through the first flow channel.

[0037] The present manifold may further be characterized by the following features Al to A10, with Features A2 to A10 being preferred or optional:

[0038] Feature Al - The manifold is configured to detachably receive the water tank and comprises a first connector for releasably communicating the first flow channel to a mating first tank connector of the water tank, and a second connector for releasably communicating the second flow channel to a mating second tank connector of the water tank.

[0039] Feature A2 - The manifold is configured to detachably receive the water tank and comprises a first connector for releasably communicating the first flow channel to a mating first tank connector of the water tank, and a second connector for releasably communicating the second flow channel to a mating second tank connector of the water tank, wherein the manifold comprises a water tank configured to be detachably received on the manifold, and the water tank comprises a first valve arranged to be automatically opened when the first connector of the manifold is connected to the mating first tank connector, and a second valve arranged to be automatically opened when the second connector of the manifold is connected to the mating second tank connector.

[0040] Feature A3, in combination with Feature Al or Feature A2 - The manifold includes the water tank such that the volume of the water tank communicates with the first flow channel and the second flow channel.

[0041] Feature A4, in combination with any one of Features Al to A3 - The manifold comprises a valve for selectively opening / closing communication of the first flow channel with a flow passage downstream of the first flow channel.

[0042] Feature A5, in combination with any one of Features Al to A4 - The third flow channel is connected to the first flow channel upstream of the valve.

[0043] Feature A6, in combination with any one of Features Al to A5 - The second flow channel has a volume of 1 ml or less.

[0044] Feature A7, in combination with any one of Features Al to A6 - The third flow channel is dimensioned to provide a flow rate through the third flow channel between 0.02 l / h and 5 l / h.

[0045] Feature A8, in combination with any one of Features Al to A7 - The third flow channel is dimensioned to provide a pressure drop of 1 mbar or less when water is filled and / or drained into / from the tank through the first flow channel.

[0046] Feature A9, in combination with any one of Features Al to A8 - The first flow channel is dimensioned to provide a flow rate of up to 2.0 l / min, preferably of up to 1.6 l / min.

[0047] Feature A10, in combination with any one of Features Al to A9 -The pressure sensor mounted in the manifold is configured to allow a measurement of the static pressure in the water tank of between 0 and 150 mbar, preferably of between 0 and 30 mbar.

[0048] The manifold for a water tank as described herein provides the advantages that the stagnant water around the pressure sensor is replaced during operation, i.e. when water is filled into and / or drained from the tank, thus avoiding stimulation of bacteria growth and water contamination.

[0049] The described advantages of the system can be expediently achieved in particular if the system comprises at least one (portable) water tank. The at least one water tank may be detachably connected to the at least one pre-purification adapter and / or the at least one post-purification adapter. The connection is such that pre-purified water can enter the water tank via the pre-purification adapter when the water tank is connected to the prepurification adapter, while pre-purified water can be removed from the water tank into the post-purification unit via the post-purification adapter when the water tank is connected to the post-purification adapter.

[0050] The present (portable) water tank preferably has a volume of at most 10 I, for example, of at most 9 I, or of at most 8 I, or of at most 7 I, or of at most 6 I. Preferably, the present (portable) water tank has a volume of at least 1 I. Generally, particularly suited is a (portable) water tank having a volume of at least 2 I and of at most 5 I.

[0051] If the at least one water tank has a closure for forcibly closing a connection for flow of prepurified water therethrough when not connected to the pre-purification adapter or the post-purification adapter, contamination of the pre-purified water in the water tank can be prevented while it is being switched back and forth between the pre-purification adapter and the post-purification adapter. In this regard, it may be particularly convenient and simple if the closure is spring-loaded, with spring means being provided to move the closure to a closed position by means of the restoring force of the spring means. The closure can then be adjusted back to the open position, against the restoring force of the spring means, to supply pre-purified water to the water tank or to remove pre-purified water from the water tank. To adjust the closure from the closed position to the open position, a projection of the pre-purification adapter or the post-purification adapter can at least in part engage in the water tank. The corresponding form of the closure forcibly moves the closure to the open position, and the closure is moved back to the closed position when the pre-purification adapter or the post-purification adapter disengages from the water tank.

[0052] Independently of this, the at least one water tank can have a seal for sealing the connection, which serves to allow pre-purified water to flow through from the prepurification adapter and / or into the post-purification adapter. This prevents any undesirable leakage or contamination of the pre-purified water when the water tank and pre-purification adapter or post-purification adapter are in the connected state. It is primarily irrelevant whether the pre-purified water is contained in the pre-purification unit, the water tank or the post-purification unit.

[0053] For ease of handling, the at least one water tank may have a handle for moving the water tank from the pre-purification adapter to the post-purification adapter and back again. In this context, it is also space-saving if the handle can be pivoted so that it only protrudes from the water tank when the handle is held by an operator. To ensure that the filling level of the pre-purified water in the water tank can always be easily checked, it can be useful if the water tank is at least partially formed from a transparent plastic.

[0054] In order that the pre-purification unit for pre-purification of the water and the postpurification unit for post-purification of the water can be operated simultaneously, it is expedient if at least two (portable) water tanks of more or less identical design are provided. It is even simpler if the water tanks are of at least substantially identical design. Independently of this, one water tank can then be connected to the at least one prepurification adapter and another water tank can be connected to the at least one postpurification adapter. In this case, the pre-purification unit and the post-purification unit can be operated simultaneously. It is particularly advantageous for the present water purification system to comprise at least as many water tanks as the total number of prepurification adapter(s) and post-purification adapter(s).

[0055] The present water purification system may also comprise a pre-purification unit and at least two pre-purification adapters, with the at least two pre-purification adapters fixedly (and liquid tightly) connected to the pre-purification unit. Such connection may be done either in parallel or in sequence, i.e. water tanks connected to each of these at least two pre-purification adapters would either be filled simultaneously or one after the other. The present water purification system may preferably comprise up to five, or up to four, or up to three, or up to two pre-purification adapters. In a particularly preferred version, the present water purification system comprises two pre-purification adapters.

[0056] The use of at least two pre-purification adapters allows to compensate for the lower production rate (or flow rate) of the pre-purification unit (for example, 1 l / min) in comparison to the production rate (orflow rate) of the post-purification unit (for example, 2 l / min). It further allows advance preparation (for example, by using a timer) of a sufficient volume of pre-purified water, for example in time for the start of a workday or a work shift in a laboratory.

[0057] In order to be able to dose the post-purified water easily, accurately and as required, the post-purification unit may comprise a manual dispenser in order to be able to dose postpurified water manually. If present, such dispenser may be fixedly connected to the (downstream side of the) post-purification unit. To simplify this and to be able to better adapt the flow rate of the dispenser to the respective requirements, the dispenser may also have a manually operated adjustment device for adjusting the flow rate of postpurified water. However, though generally intended to be used with the herein described dispenser the present water purification system may also be - without making use of such a dispenser - directly connected to any equipment, such as any chemical, biological, and analytical laboratory equipment as well as any other instruments, such as dialysis instruments, requiring a supply of purified water, particularly of highly purified or ultrapure water, provided that such equipment is self-metering, i.e. comprises a valve for controlling feed rate and feed volumes of purified water to the laboratory equipment.

[0058] Though the present dispenser may comprise any suitable valve arrangement allowing to control the flow of the to be dispensed post-purified water, preferably from dropwise up to the maximum dispensing rate of the system, it is nevertheless preferred that the dispenser comprises a valve assembly comprising two ceramic discs (or a "pair" of discs), which in the following may also be referred to as "first disc" and "second disc", respectively, as described in the following.

[0059] Preferably, this pair of first disc and second disc is to be rotated relative to each other with mutually facing first and second sealing contact surfaces arranged to at least partly slide in contact with each other, wherein the first disc has at least one window, wherein the second disc has a solid portion arranged to completely cover and thus to close the at least one window of the first disc in a fully closed rotational position, and an opening portion arranged to at least partially expose the at least one window of the first disc in a fully open rotational position.

[0060] Preferably, the solid portion of the second disc that is arranged to completely cover to close the at least one window of the first disc in the fully closed rotational position is formed so as to include a portion of the second sealing contact surface that overlaps the first sealing contact surface of the first disc surrounding an edge of the window by a sealing zone with a width of at least 1.5 mm, preferably at least 2.0 mm.

[0061] Preferably, the first and second sealing contact surfaces of the pair of first and second discs arranged to at least partly slide in contact with each other have a surface roughness Ra of at most 0.60 pm, and / or a surface flatness of at most 0.80 pm, and are preferably polished or ground.

[0062] Preferably, the mutually facing first and second sealing contact surfaces of the pair of first and second discs are arranged such that a percentage of 50-80%, preferably 55-75%, most preferably 60-70% of the first and second sealing contact surfaces are sliding in contact with each other between the fully closed rotational position and the fully open rotational position.

[0063] Preferably, the second disc is freely floating in contact with the first disc or is biased towards the first disc by a biasing member.

[0064] Preferably, the at least one window of the first disc has a notch / dent recessed into the material of the first disc from the plane defined by the first sealing contact surface of the first disc at an / the edge of the at least one window at a side where the exposure of the at least one window starts upon movement of the second disc from the fully closed rotational position in the direction towards the fully open rotational position.

[0065] Preferably, the notch / dent has a pointed tip widening and / or deepening gradually towards the at least one window.

[0066] Preferably, the at least one window has an inclination or ramp at a sidewall adjacent to a / the side where the exposure of the at least one window starts upon movement of the second disc from the fully closed rotational position in a / the direction towards the fully open rotational position such that the free opening width of the at least one window in the thickness direction of the first disc becomes gradually narrower with distance from the plane of the first sealing contact surface.

[0067] Preferably, the valve assembly is dimensioned so as to provide, within the rotational angular range of the relative movement between the fully closed rotational position and the fully open rotational position, a flowrate through the at least one window from dropwise, preferably 20 ml • min-1, up to at most 5 I • min-1, more preferably at most 4 I • min-1, even more preferably at most 3 I • min-1, and most preferably at most 2 I • min-1.

[0068] Preferably, the rotational angular range between the fully closed rotational position and the fully open rotational position is 50°-70°, preferably 55°-65°, and most preferably about 60°.

[0069] Preferably, the first disc is provided with positioning notches for preventing a rotation and defining a mounting position in a receptacle of a liquid dispenser, the positioning notches being formed and / or arranged unsymmetrical about a circumference of the first disc. Preferably, the second disc is provided with one or more driver recess / recesses and / or protrusion / protrusions on a side opposite to the second sealing contact surface, for engagement with a rotary actuator of a liquid dispenser.

[0070] Preferably, the first disc has a circular outer periphery, and the second disc has a noncircular outer periphery with the opening portion arranged to at least partially expose the at least one window of the first disc radially recessed from the outer periphery.

[0071] Preferably, the first disc and / or the second disc are made of a ceramic material, preferably aluminum oxide ceramic.

[0072] Preferably, the first disc of the valve assembly is rotationally fixed in position within the receptacle such that the at least one window communicates with the outlet, and the second disc is mounted in the receptacle so as to freely float in contact with the first disc and such that the first and second sealing contact surfaces are pressed against each other by the water pressure from the supply piping acting on the second disc.

[0073] Preferably, the second disc of the valve assembly is engaged with (or "mechanically connected to") a manually operable rotary actuator (for example, a handwheel) for rotatingly driving the second disc relative to the first disc between the fully closed rotational position and the fully open rotational position.

[0074] The manually operable rotary actuator may be directly or indirectly mechanically connected to the second ("upper") disc of the present valve assembly. In case of a direct connection, said rotary actuator comprising an optional short axle integrally formed with the rotary actuator rotatingly drives the second disc relative to the first disc between the fully closed rotational position and the fully open rotational position. In case of an indirect connection, said rotary actuator is mechanically connected to the second ("upper") disc via an axle (or "shaft"), wherein the rotary actuator and the axle are separate pieces. Preferably, the axle may be comprised of two different separate pieces, an axle and a driver, wherein the rotary actuator is mechanically connected to the axle, which in turn is mechanically connected to the driver, which again in turn is mechanically connected to the second ("upper") disk.

[0075] Thus, a preferred dispenser comprises a manually operable rotary actuator (e.g. a handwheel), a valve assembly comprising two ceramic discs, and an axle connecting said rotary actuator to one of said ceramic discs (preferably the second ("upper") disc), thereby allowing the opening and closing of the valve by turning the rotary actuator.

[0076] It is to be understood that the manually operable rotary actuator and the second ("upper") disk and - if present - the axle and / or the driver, are mechanically connected to each other in such a way as to allow smooth and precise rotational movement, as will be explained in more detail in the following.

[0077] The preferred valve assembly as described herein is a mechanical valve assembly including a single pair of discs, preferably made from ceramic material, that can be integrated in the dispenser of water purification systems to replace both, the motorized valve and the solenoid valve. This single pair of discs can be used to control both, the opening and closing of the flow through the valve assembly, as well as the dispensing flowrate from dropwise dispensing to high flowrates, i.e. from 20 ml • min1to at most 5 I • min-1, more preferably to at most 4 I • min-1, even more preferably to at most 3 I • min-1, and most preferably to at most 2 I • min-1.

[0078] The present valve assembly comprised in the present dispenser for dispensing the postpurified water may thus be characterized by the following features Bl to B14, with Features B2 to B14 being preferred or optional:

[0079] Feature Bl - A valve assembly comprising a pair of first and second discs to be rotated relative to each other with mutually facing first and second sealing contact surfaces arranged to at least partly slide in contact with each other, wherein the first disc has at least one window, and wherein the second disc has a solid portion arranged to completely cover to close the at least one window of the first disc in a fully closed rotational position, and an opening portion arranged to at least partially expose the at least one window of the first disc in a fully open rotational position.

[0080] Feature B2, in combination with Feature Bl - The solid portion of the second disc that is arranged to completely cover to close the at least one window of the first disc in the fully closed rotational position is formed so as to include a portion of the second sealing contact surface that overlaps the first sealing contact surface of the first disc surrounding an edge of the window by a sealing zone with a width of at least 1.5 mm, preferably at least 2.0 mm.

[0081] Feature B3, in combination with Feature Bl and Feature B2 - The first and second sealing contact surfaces of the pair of first and second discs arranged to at least partly slide in contact with each other have a surface roughness Ra of at most 0.60 pm, and / or a surface flatness of at most 0.80 pm, and are preferably polished or ground. Feature B4, in combination with any one of Features Bl to B3 - The mutually facing first and second sealing contact surfaces of the pair of first and second discs are arranged such that a percentage of 50-80%, preferably 55-75% of the first and second sealing contact surfaces are sliding in contact with each other between the fully closed rotational position and the fully open rotational position.

[0082] Feature B5, in combination with any one of Features Bl to B4 - The second disc is freely floating in contact with the first disc or is biased towards the first disc by a biasing member.

[0083] Feature B6, in combination with any one of Features Bl to B5 - The at least one window of the first disc has a notch / dent recessed into the material of the first disc from the plane defined by the first sealing contact surface of the first disc at an / the edge of the at least one window at a side where the exposure of the at least one window starts upon movement of the second disc from the fully closed rotational position in the direction towards the fully open rotational position.

[0084] Feature B7, in combination with any one of Features Bl to B6 - The notch / dent has a pointed tip widening and / or deepening gradually towards the at least one window.

[0085] Feature B8, in combination with any one of Features Bl to B7 - The at least one window has an inclination or ramp at a sidewall adjacent to a / the side where the exposure of the at least one window starts upon movement of the second disc from the fully closed rotational position in a / the direction towards the fully open rotational position such that the free opening width of the at least one window in the thickness direction of the first disc becomes gradually narrower with distance from the plane of the first sealing contact surface.

[0086] Feature B9, in combination with any one of Features Bl to B8 - The valve assembly is dimensioned so as to provide, within the rotational angular range of the relative movement between the fully closed rotational position and the fully open rotational position, a flowrate through the at least one window from dropwise, preferably 20 mL / min, up to 2 L / min.

[0087] Feature BIO, in combination with any one of Features Bl to B9 - The rotational angular range between the fully closed rotational position and the fully open rotational position is 50°-70°, preferably 55°-65°, and most preferably about 60°.

[0088] Feature Bll, in combination with any one of Features Bl to B10 - The first disc is provided with positioning notches for preventing a rotation and defining a mounting position in a receptacle of a liquid dispensing unit, the positioning notches being formed and / or arranged unsymmetrical about a circumference of the first disc.

[0089] Feature B12, in combination with any one of Features Bl to Bll - The second disc is provided with one or more driver recess / recesses and / or protrusion / protrusions on a side opposite to the second sealing contact surface, for engagement with a rotary actuator of a liquid dispensing unit.

[0090] Feature B13, in combination with any one of Features Bl to B12 - The first disc has a circular outer periphery, and the second disc has a non-circular outer periphery with the opening portion arranged to at least partially expose the at least one window of the first disc radially recessed from the outer periphery.

[0091] Feature B14, in combination with any one of Features Bl to B13 - The first disc and / or the second disc are made of a ceramic material, preferably aluminum oxide ceramic.

[0092] This preferred mechanical valve assembly as described herein, in consequence of its reduced size and complexity, provides one or more of the following advantages over existing products:

[0093] (i) The ability to have several dispensers and / or dispensing devices for dispensing at different flowrates at the same time in a single water purification system;

[0094] (ii) the size of the dispenser and / or dispensing device can be reduced by removing the solenoid valve (and the motorized valve if provided) and the PCB from the dispenser and / or dispensing device - this provides an improved ergonomic handling of the dispenser and / or dispensing device;

[0095] (iii) the number of components and the complexity of the dispenser and / or dispensing device and / or the distribution system can be reduced - in particular, avoiding the electronics means because no power or control circuits must be provided from the main system comprising the water purification unit to the distribution system and / or the dispenser and / or dispensing device, and a connection between the main system to the distribution system and / or dispenser and / or dispensing device may be reduced to a dual or single tubing instead of two separate tubings and electronic cables, which all may have to be integrated in an outer sleeve or bound together by suitable means as, for example, cable ties;

[0096] (iv) the simplification of the structure and lack of electronics is also beneficial from an environmental perspective, reducing the carbon footprint of the distribution system and / or the dispensing device and / or the dispenser as well as of the entire water purification system and improving its recyclability;

[0097] (v) the possibility to omit electronic parts from the dispensing unit and / or distribution unit further simplifies maintenance and repair of the unit in case of need as no electronic connections need to be made; (vi) from a manufacturing perspective, the valve assembly together with the liquid dispensing device and / or dispenser provided with it provide for a simplified and more robust, i.e. error free assembly; and

[0098] (vii) finally, the valve assembly and the liquid dispensing device and / or dispenser provided with it enhance the freedom of design: having electronic parts close to hydraulic components in a small and closed space poses a risk and puts severe constraints on the design of the purified water distribution system(s) and / or the dispensing device(s) and / or the dispenser(s), forcing a flow entry from the lower part of a dispenser in most existing products. The lack of electronics made possible by the use of the present mechanical valve assembly simplifies the constraints on the design of the distribution system and / or dispensing device and / or dispenser as well as of the overall water purification system, and consequently lowers the risks from that perspective.

[0099] Preferably the post-purification unit and the dispenser are fixedly connected to each other by a feeding line for the post-purified water as described in the following.

[0100] The feeding line (or post-purified water feeding line) provides (or delivers) post-purified water to the dispenser and again removes water that has not been dispensed from the dispenser, back to the water purification unit wherein it is then subjected to one or more purifying step(s). Providing such flow to and from ("cycling") the dispenser avoids buildup of contaminants in stagnant water, for example by extraction from the materials used for the tubing to conduct the purified water. Such cycling may either be done continuously, or preferably in order to reduce energy consumption non-continuously, for example by regularly cycling for a period (or duration) of time sufficient to remove and / or re-purify any stagnant water in the loop (including the feeding line). The period of time from such cycling to another, i.e. the time in between cycling, may be determined, for example, on basis of the amount of contaminants introduced into the purified water in a certain period of time and / or what level of purity of the purified water is desired.

[0101] The present water feeding line comprises, or preferably consists of, an integral multilumen tubing. Such integral multi-lumen tubing comprises at least two (for example, two, or three, or four, or five, or six, or seven, or eight, or even more than eight) separate lumens in a single ("integral") tubing serving as flow paths for feeding water to and from the dispenser, respectively. It is noted that, irrespective of the total number of lumens comprised in such integral multi-lumen tubing, at least one (for example, one, or two, or three, or four, or even more than four) lumen serves as flow path (or channel) to provide (purified) water to the dispenser, and at least one (for example, one, or two, or three, or four, or even more than four) lumen serves as flow path (or channel) to remove nondispensed purified water from the dispenser.

[0102] Preferably, the present integral multi-lumen tubing comprises at least one (for example, one, or two, or three, or four, or even more than four) central lumen and at least one (for example, one, or two, or three, or four, or even more than four) peripheral (or outer) lumen, with each lumen separate from any other.

[0103] Preferably, the present integral multi-lumen tubing comprises at least two (for example, two, or three, or four, or five, or six, or seven, or eight, or even more than eight) lumens that are symmetrically distributed around at least one central lumen, with each lumen separate from any other.

[0104] Preferably, the present integral multi-lumen tubing comprises, or preferably consists of, a low-leachables material, preferably a low-leachables polymer. Such low-leachables polymer may, for example, be selected from the group consisting of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF, also referred to as polyvinylidene difluoride), perfluoroalkoxy polymers (PFA), and low-density polyethylene (LDPE), with low-density polyethylene being preferred.

[0105] Preferably, the present feeding line comprises a protective sheath surrounding the integral multi-lumen tubing. Such a sheath may surround the integral multi-lumen tubing either tightly, i.e. without any free volume between the sheath and the outer surface of the integral multi-lumen tubing, or loosely, i.e. with free volume between the sheath and the outer surface of the integral multi-lumen tubing. Preferably, such sheath surrounds the integral multi-lumen tightly, with the sheath and the integral multi-lumen tubing being co-extruded. Co-extrusion of the sheath and the integral multi-lumen tubing results in strong adhesion between both, essentially making it an integral sheathed multi-lumen tubing.

[0106] Preferably, the protective sheath comprises, preferably consists of, a material different from that of the integral multi-lumen tubing.

[0107] Preferably, the present feeding line, including - if present - a protective sheath, is flexible. Such flexible feeding line is then preferably made of low-density polyethylene. This will allow for easy handling of the dispensing device and improve ergonomics. Such preferred feeding line may thus be fully characterized by the following features Cl to C7, with Features C2 to C7 being preferred or optional:

[0108] Feature Cl -The present feeding line comprises an integral multi-lumen tubing, the integral multi-lumen tubing comprising at least two separate lumens serving as flow paths for feeding water to and from the dispenser, respectively.

[0109] Feature C2, in combination with Feature Cl - The integral multi-lumen tubing comprises, or preferably consists of, a low leachable material, preferably a polymer, such as low-density polyethylene.

[0110] Feature C3, in combination with Feature Cl or Feature C2 - The feeding line is flexible.

[0111] Feature C4, in combination with any one of Features Cl to C3 - The feeding line comprises a protective sheath surrounding the integral multi-lumen tubing.

[0112] Feature C5, in combination with any one of Features Cl to C4 - The integral multilumen tubing comprises at least one central lumen and at least one, preferably plural outer lumens separated / isolated from the central lumen.

[0113] Feature C6, in combination with any one of Features Cl to C5 - The integral multilumen tubing comprises at least two, preferably at least three or four outer lumens distributed symmetrically about the at least one central lumen.

[0114] Feature C7, in combination with any one of Features Cl to C6 - The feeding line is connected or connectable to a water purification unit such that the flow of purified water towards the dispenser is directed through at least one of the at least one central lumen and any flow of purified water back to the purification unit and / or another dispenser is directed through one or more of the outer lumens.

[0115] In a first particularly preferred embodiment, the laboratory as described herein in connection with the present water purification system comprises more post-purification units than pre-purification units. In such a case, for example, a single pre-purification unit can be used to supply several post-purification units with pre-purified water. It goes without saying that an even larger number of post-purification units can be supplied with pre-purified water with a larger number of pre-purification units. In many cases, it may be preferable with regard to the size of the pre-purification units and the post-purification units that the present water purification system comprises at least twice as many postpurification units than pre-purification units, preferably at least three times as many postpurification units than pre-purification units, in particular four times as many postpurification units than pre-purification units. In principle, this also allows the post-purification units to be arranged on different laboratory benches, as required, in each case where there is a workstation at which postpurified water or ultrapure water is required. In this way, even large laboratories and / or laboratories with several laboratory rooms, possibly even located on different floors, can be operated with one system for providing ultrapure water at different workplaces. It may also be possible in such large laboratories to supply a whole multiplicity of postpurification units with a single pre-purification unit or with a few pre-purification units. Particularly for such large laboratories, and especially if there is only sporadic need for highly purified or ultrapure water, the present water purification system may be very advantageous because it eliminates the need for continuous re-circulation of highly purified or ultrapure water (to avoid the accumulation of any contaminants in the water), which is cost- and maintenance-intensive, while still allowing for a continuous and assured supply of highly purified or ultrapure water.

[0116] Depending upon the specific requirements of a particular chemical, biological, or analytical laboratory the present water purification system can easily be configured to satisfy these requirements.

[0117] For example, for a laboratory having a work bench or workstation that is the predominant point of use of highly purified or ultrapure water, a water purification system comprising in sequence and fixedly connecting a pre-purification unit as defined herein, two prepurification adapters as defined herein, and a post-purification unit as defined herein, and the water purification system also comprising at least two (portable) water tanks as defined herein, wherein the two pre-purification adapters are serially fixedly connected to the pre-purification unit, might prove advantageous. For reasons of clarity, it is noted that in such a system, either one or both of the pre-purification adapter(s) also serves / serve as post-purification adapter. Such a specific configuration of the prepurification would allow continuous withdrawal of highly purified or ultrapure water at the predominant point of use via one of the pre-purification adapters through a first water tank, while also allowing a second water tank to be filled via the other pre-purification adapter and then moved to any other post-purification unit spatially separated from this predominant point of use.

[0118] For example, for a laboratory requiring purified water of two different purities the following water purification system might prove advantageous, such system comprising (i) component SI comprising a pre-purification unit, and a pre-purification adapter as defined herein, both fixedly connected to each other; (ii) component S2 comprising a first post-purification unit, and a first post-purification adapter as defined herein, both fixedly connected to each other;

[0119] (iii) component S3 comprising a second post-purification unit, and a second postpurification adapter as defined herein, both fixedly connected to each other; and

[0120] (iv) at least one water tank as defined herein, wherein component SI is spatially separated from components S2 and S3; wherein the pre-purification unit comprises an active carbon filter or a filtration unit as defined herein as sole purifying means; wherein the first post-purification unit only comprises a reverse osmosis unit as defined herein or an electrodeionization unit as defined herein as sole purifying means; wherein the second post-purification unit comprises a first post-purification subunit and a second post-purification sub-unit, with the first post-purification sub-unit comprising a reverse osmosis unit as defined herein and / or an electrodeionization unit as defined herein as sole purifying means, and with the second post-purification sub-unit comprising one or more selected from the group consisting of an ion exchanger unit as defined herein, an activated carbon unit as defined herein, and a UV unit as defined herein, with the ion exchanger unit being downstream of the UV unit- if both are present.

[0121] In general terms, the present method relates to providing purified water and / or to operating the water purification system as defined herein, the method comprising the steps of pre-purifying feed water, feeding the pre-purified water into a (portable) water tank, moving said water tank to a spatially separated post-purification unit, post-purifying (or polishing) the pre-purified water, and - optionally -finally dispensing the post-purified water.

[0122] In a first particularly preferred embodiment of the method, the pre-purified water is fed from a pre-purification unit via a pre-purification adapter into a (portable) water tank and the (portable) water tank, which is then at least partially filled with pre-purified water (with the filling level also being determined by the required volume of purified water), is separated from the pre-purification adapter. The water tank is then moved manually to a post-purification adapter and connected thereto. The pre-purified water can then be transferred from the water tank to the post-purification unit via the post-purification adapter and post-purified in the further post-purification unit to provide post-purified water that may then be dispensed via a dispenser fixedly (and liquid tightly) connected to the post-purification unit. Thus, the present application relates to a method of operating the present water purification system as defined herein, particularly in a laboratory, wherein tap water is supplied via the water connection to the at least one prepurification units and is pre-purified in the pre-purification units to produce pre-purified water, wherein the pre-purified water is fed into a water tank via a pre-purification adapter, wherein the water tank, at least partially filled with pre-purified water, is separated from the pre-purification adapter, moved manually to the post-purification adapter and connected to the post-purification adapter, wherein the pre-purified water is fed from the water tank to the post-purification unit via the post-purification adapter and is post-purified in the post-purification unit to produce post-purified water, and optionally wherein the post-purified water is dispensed via a dispenser fixedly connected to the post-purification unit.

[0123] The method described above may also be performed in the same manner with at least one further (portable) water tank, thus permitting, for example, two or more postpurification units to be operated with one pre-purification unit.

[0124] Hence, the present application further relates to a preferred method as defined above, wherein the pre-purified water is fed into another water tank via a pre-purification adapter, wherein the further water tank at least partially filled with pre-purified water is separated from the pre-purification adapter, moved manually to a further postpurification adapter and connected to the further post-purification adapter, wherein the pre-purified water is fed from the further water tank into the further post-purification unit via the further post-purification adapter and is post-purified in the further post-purification unit to produce post-purified water, and optionally, wherein the post-purified water is dispensed via a dispenser fixedly connected to the further post-purification unit.

[0125] Independently of this, upon separating the water tank from the pre-purification adapter, the closure of the water tank and the closure of the pre-purification adapter are automatically moved into a closed state. Any accidental contamination of the pre-purified water in the pre-purification unit or the water tank can consequently be avoided or at least reduced. Also, unwanted leakage will not occur then. When connecting the water tank to the pre-purification adapter, the closure of the water tank and the closure of the pre-purification adapter are forced open, pre-purified water can be fed from the prepurification unit into the water tank without any further action.

[0126] Similarly, when the water tank is separated from the post-purification adapter, the closure of the water tank and the closure of the post-purification adapter should be forcibly closed. Contamination of the pre-purified water in the post-purification unit or in the water tank does not occur. Also, there will then be no undesirable leakage. If, the closure of the water tank and the closure of the post-purification adapter are forcibly opened when connecting the water tank to the post-purification adapter, pre-purified water can be fed from the water tank into the post-purification unit without any further measures.

[0127] Consequently, the present application also relates to a preferred method as defined above, wherein a closure of the water tank and of the water tank connection of the prepurification unit is forced from an open state to a closed state when the water tank is disconnected from the pre-purification adapter, and / or wherein a closure of a connection of the water tank and of the water tank, the prepurification adapter and the post-purification adapter is forced from a closed state to an open state when the water tank is connected to the post-purification unit, and / or wherein the pre-purification adapter, the water tank and / or the post-purification adapter comprises a seal for sealing a connection for the flow of pre-purified water in the state of the pre-purification adapter and / or the post-purification adapter connected to the water tank.

[0128] In the following, the water purification system of the present application will be explained in more detail by reference to the following schematic drawings showing exemplary nonlimiting embodiments:

[0129] Figure 1 shows an exemplary, schematic representation of a water purification system as described herein.

[0130] Figure 2 shows an exemplary, schematic representation of a method for operating the water purification system described herein.

[0131] Figure 3 shows an exemplary, schematic representation of the present water purification system installed in a laboratory with multiple workstations. Figure 4 shows an exemplary, schematic representation of an exemplary manifold for a water tank as may be used in the present water purification system.

[0132] Figure 5 shows a schematic representation of an exemplary water purification system. Figure 6a shows a schematic representation of an exemplary integral multi-lumen tubing as may be used herein.

[0133] Figure 6b shows a schematic representation of the exemplary integral multi-lumen of Figure 6a surrounded by a tight protective sheath.

[0134] Figure 6c shows a schematic representation of the exemplary integral multi-lumen tubing of Figure 6a surrounded by a loose protective sheath.

[0135] Figure 7 shows a perspective schematic view of an exemplary first disc of a valve assembly in accordance with the present application.

[0136] Figure 8 shows a perspective schematic view of an exemplary second disc of the valve assembly in accordance with the present application.

[0137] Figure 9 shows a schematic top view of an exemplary valve assembly in accordance with the present application with the first disc as shown in Figure 7 and the second disc as shown in Figure 8 superimposed on each other.

[0138] Figure 10 shows a schematic representation of an exemplary dispenser of the present application.

[0139] Figure 11a shows a schematic cross-sectional view of an exemplary dispenser in accordance with the present application, with the valve assembly of the present application in the closed position.

[0140] Figure lib shows a schematic cross-sectional view of an exemplary dispenser in accordance with the present application, with the valve assembly of the present application in an open position.

[0141] Figure 1 shows a water purification system 1 for providing ultrapure water 2, particularly suited for laboratory applications. The system 1 comprises a pre-purification unit 3 for the pre-purification of a feed water stream, for example, tap water 4. To obtain the tap water 4 to be purified, the pre-purification unit 3 is permanently connected via a water connection 5 to a water line 6 for tap water 4 in a laboratory. The pre-purification unit 3 can, for example, stand on a table or the like or be mounted on a wall. The pre-purification unit 3 as shown has a first cleaning unit 7 (or first pre-purification sub-unit 7) and a second cleaning unit 8 (or second pre-purification sub-unit 8) in sequence. The tap water 4 flows through these two cleaning units 7,8 one after the other.

[0142] In the illustrated and in this respect preferred system 1, the first pre-purification sub-unit

[0143] 7 is one that comprises a depth filter and / or an activated carbon filter. In the first pre- purification sub-unit 7, the water first flows through a depth filter in which particles are separated by means of depth filtration. Subsequently, the depth-filtered water enters an activated carbon filter in which free chlorine is separated by adsorption. The depth filter and the activated carbon filter are preferably accommodated together in a replaceable filter cartridge 9 (though it is also possible to accommodate them in two separate filter cartridges), preferably in such a way that the flow passes radially through the depth filter and the activated carbon filter one after the other from the outside to the inside.

[0144] The filtered water passes into the second pre-purification sub-unit 8, which in the system shown and preferred in this respect is a reverse osmosis unit that has a corresponding semipermeable membrane. This semipermeable membrane is accommodated in a replaceable membrane cartridge 10 in which the water can be placed under a sufficiently high pressure. Generally, the pressure of the tap water 4 is sufficient for pushing the water through both the first pre-purification sub-unit 7 and the second pre-purification sub-unit 8. In case tap water pressure is not sufficient or subject to changes, first pre-purification sub-unit 7 may comprise a pump (not shown) to provide sufficient water pressure for operating the second pre-purification sub-unit 8, which preferably is a reverse osmosis unit.

[0145] Subsequently to the pre-purified water leaving the second pre-purification sub-unit 8, which may be for example a reverse osmosis unit, it is fed via a pre-purification adapter 11 into a water tank 12 connected to the pre-purification adapter 11. The pre-purification adapter 11 is firmly connected to the pre-purification unit 3. Water tank 12 on the other hand is detachably connected to the pre-purification adapter 11. In system 1 as shown, the water tank 12 is mounted from above onto the pre-purification adapter 11, thereby forcibly creating a fluid connection between the interior of the water tank 12 and the prepurification adapter 11. The watertank 12 and the pre-purification adapter 11 can thereby engage with each other, whereby a closure of the water tank 12 and a closure of the prepurification adapter 11 are each forcibly adjusted from a closed position to an open position. In this way, a connection is created between the water tank 12 and the prepurification adapter 11. In this case, the water tank 12 and / orthe pre-purification adapter 11 is provided with a seal to prevent leakage of pre-purified water 13.

[0146] Depending upon the purity of the tap water 4 provided to the present water purification system 1, the pre-purification unit 3 may also only comprise the second pre-purification sub-unit 8, for example only a reverse osmosis unit. When the water tank 12 is lifted off the pre-purification adapter 11, the water tank 12 and the pre-purification adapter 11 are disengaged, which forces the closure of the water tank 12 and the closure of the pre-purification adapter 11 back from the open position to the closed position. The water tank 12 can then be carried to a post-purification adapter 14 and placed thereon. The water tank 12 and the post-purification adapter 14 then engage with each other, forcing the closure of the water tank 12 and the closure of the postpurification adapter 14 to be changed from the closed position to the open position. As for the connection of the water tank 12 with the pre-purification adapter 11 and the postpurification adapter 14, these connections are made in the same way and these connections are also formed in the same way.

[0147] The pre-purified water 13 can now be fed from the water tank 12 via the post-purification adapter 14 into a post-purification unit 15 which is permanently connected to the postpurification adapter 14. A pump (not shown) is provided forthis purpose. The pre-purified water 13 is post-purified by passing through UV oxidation unit 17, wherein the water is irradiated with UV light to oxidize and / or decompose organic compounds and / or components of bacteria, viruses, and / or germs, thereby killing the bacteria, viruses, and / or germs, and producing organic ionic compounds. The water is then passed through an ion exchanger accommodated in an ion exchanger cartridge 16. The ion exchanger consists essentially of an ion exchange resin and is used to remove unwanted ions from the pre-purified water 13, thereby resulting in post-purified water 19 (e.g. ultrapure water).

[0148] In system 1 as shown the subsequently purified water can be dispensed via a manual dispenser 18. The volume flow of the post-purified water 19 can also be manually adjusted during dosing. Though the distance between the post-purification unit 15 and the dispenser 18 may vary, it is preferred not to choose a too long distance so as to avoid or reduce the potential leaching of contaminants from any tubing connecting the postpurification unit 15 and dispenser 18.

[0149] Figure 2 shows a laboratory 20 with several rooms 21, whereby several workplaces 22 can be provided in each room. At some of these workplaces 22 ultrapure water is required, whereby the use of the ultrapure water at the laboratory workplaces 22 on different laboratory benches 23 can be very different. In exemplary laboratory 20 as shown, a system 1 for providing ultrapure water as described herein is provided. The prepurification unit 3 and the - shown are three - post-purification units 15 are each spaced considerably apart from each other, though it is of course possible to also place one or more post-purification units 15 in close proximity to the pre-purification unit 3, in spite of such an approach somewhat counteracting the advantages of the present water purification system. Permanently connected to each of the post-purification units 15 is a post-purification adapter 14 and a dispenser 18. The post-purification adapters 14 of the post-purification units 15 are designed in the same way, so that similar water tanks 12 can be optionally placed on each of the post-purification adapters 14 to create a fluid connection between the interior of the water tank 12 and the respective post-purification unit 15. Thus, a water tank 12 partially filled with pre-purified water 13 can be lifted from the pre-purification adapter 11 and moved to and connected to any one of the postpurification adapters 14 by placing it on top of the post-purification adapter 14 of choice. At the same time, a water tank 12 can be detached from any of the post-purification adapters 14 and carried to the pre-purification adapter 11, where it can be connected to the pre-purification adapter 11 by placing it onto the pre-purification adapter 11.

[0150] Figure 3 schematically shows an exemplary process for providing ultrapure water with a system in a laboratory 20 of the type mentioned in each case. First, tap water 4 is fed from a water line 6 into a pre-purification unit 3 via a water connection 5, where it is prepurified. The water pre-purified in this way is passed by means of the feed water pressure and / or - if such pressure is not sufficient - a pump (not shown) through a pre-purification adapter 11 on which a water tank 12 is placed. The water tank 12 is connected to the prepurification adapter 11 in such a way that the pre-purified water 13 can flow into the interior of the water tank 12 without leaking. As much tap water 4 is pre-purified until the water tank 12 is filled to the desired level. A water level measurement ensures that the water tank 12 cannot overflow. The completely or only partially filled water tank 12 is removed from the pre-purification adapter 11 by a user as required. To do this, the user grips a - preferably pivotable - handle 24 of the water tank 12. When the water tank 12 is separated from the pre-purification adapter 11, the closure of the water tank 12 and the pre-purification adapter 11 are forcibly transferred from the previously open position to the closed position without further manual intervention by the user.

[0151] After lifting the water tank 12 from the pre-purification adapter 11, the user can place another, in particular empty, water tank 12 on the pre-purification adapter 11. This causes the water tank 12 and the pre-purification adapter 11 to engage with each other, whereby the closure of the water tank 12 and the pre-purification adapter 11 are forcibly moved from the closed position to the open position without manual intervention by the user. This creates a connection for pre-purified water 13 to flow through. The water tank 12 can thus be filled with water pre-purified in the pre-purification unit 3 in the same way as the previous water tank 12.

[0152] Meanwhile, the at least partially filled water tank 12 is carried by the user to a postpurification adapter 14 and placed onto the post-purification adapter 14. In the process, the closure of the water tank 12 and the post-purification adapter 14 are moved from the closed position to the open position. Subsequently to connecting the water tank 12 and the post-purification adapter 14, the pre-purified water 13 within the water tank 12 is fed by means of a pump into a post-purification unit 15, which is firmly connected to the postpurification adapter 14. In the post-purification unit 15, the pre-purified water 13 is postpurified in the manner already described and dispensed as required by a user via the dispenser 18.

[0153] The other water tank 12, which is also at least partially filled in the meantime, is lifted off the pre-purification adapter 11 by the same or another user and carried to another post- purification adapter 14 and placed on the latter. The pre-purified water 13 is pumped by a pump from the water tank 12 into the further post-purification unit 15 connected to the further post-purification adapter 14, in which post-purification of the pre-purified water 13 takes place. The post-purified water 19 can be dispensed as required using a dispenser 18.

[0154] The one pre-purification unit 3 can be used to supply several post-purification units 15 with pre-purified water 13 in the manner described. In this case, each of the at least partly filled water tanks 12 are removed from the pre-purification adapter 11 and carried to the various post-purification units 15, where they are connected to the post-purification adapters 14 connected to the post-purification units 15. When the water tanks 12 placed on the post-purification adapters 14 have been emptied, the water tanks 12 are carried back to the pre-purification unit 3 and placed there one after the other on the prepurification adapter 11 to be filled again one after the other with pre-purified water 13 by the pre-purification unit 3.

[0155] The manifold preferably used herein is now described in more detail by reference to Figure 4 showing an exemplary, schematic representation of an exemplary manifold for a water tank as may be used in the present water purification system.

[0156] It is noted that in Figure 4 reference numeral "W" is used to indicate volumes (such as, but not limited to, tank 102 (corresponding water tank 12 in Figures 1 to 3), first flow channel 109, second flow channel 108, and third flow channel 110), which when the present manifold is in use are partly or essentially fully filled with water. Alternately, when the manifold is not in use, these volumes may be partly or essentially fully filled with air. Thus, water is not necessarily considered a component of the manifold per se.

[0157] The manifold 101 for a water tank 102 comprises the connections A and B for communicating the water tank 102 with the channels of the manifold 101, in particular a first flow channel 109 for filling and / or draining the water into / from the tank 102, and a second flow channel 108 for guiding the water in the tank 102 to a pressure sensor 105 mounted in the manifold 101 so as to allow a measurement of the static pressure in the water tank 102. The pressure sensor 105 is mounted in a portion of the manifold 101 that communicates with the second flow channel 108 such that the water pressure acts on the sensitive part of the sensor.

[0158] The manifold 101 according to the exemplary embodiment also comprises a third flow channel 110 connecting the first flow channel 109 and the second flow channel 108 with each other, wherein the third flow channel 110 is configured and arranged to replace water stagnant in the second flow channel 108 when water is filled and / or drained into / from the tank 102 through the first flow channel 109. To facilitate the replacement of water in the second flow channel 108, i.e. so as to minimize the dead volume in the second flow channel 108, the third flow channel 110 preferably connects to the second flow channel 108 at a position in close proximity to pressure sensor 105.

[0159] The present manifold 101 is based on retaining two separate or distinct hydraulic streams through flow channels from the tank into the manifold but providing a third flow channel between the two streams. The aim of this third flow channel 110 is to provide a controlled water flow through the second flow channel 108 via the first flow channel 109 that is sufficient to replace at least part of the water volume in the second flow channel 108 each time the tank 102 is filled or drained, but is small enough to generate only a minimal pressure drop. Preferably, the pressure drop created by draining the water from the second flow channel 108 through the third flow channel 110 is 1 mbar or less.

[0160] The dimension of the third flow channel 110 shall be selected depending on the flow rate to be achieved through that channel and the pressure drop generated by the water flow on the first flow channel 109. In a typical water purification system for laboratory use as used herein, the equivalent diameter for the third flow channel may be around 0.8 mm. The manifold 101 is configured to detachably receive the water tank 102 and it comprises, as is known in the prior art, a first connector 104 for releasably communicating the first flow channel 109 to a mating first tank connector 114 of the water tank 102, and a second connector 103 for releasably communicating the second flow channel 108 to a mating second tank connector 113 of the watertank 102 (the connectors are shown schematically in the drawing as they may correspond to existing and well known types of connectors for fluidic communication; the connectors may thus include seals as desired to avoid spilling of water in the connected state).

[0161] The water tank 102 in the detachable variant comprises a first valve 114a arranged to be automatically opened when the first connector 104 of the manifold 101 is connected to the mating first tank connector 114, and a second valve 113a arranged to be automatically opened when the second connector 103 of the manifold 101 is connected to the mating second tank connector 113. Valves may be integrated in the manifold 101, too, such that they are automatically operated upon establishing the connection between the respective connectors. Thus, the channels in the manifold are closed to the environment when no tank is present.

[0162] In the detachable and in the integrated variant the manifold 101 may comprise a valve 106 for selectively opening / closing communication of the first flow channel 109 with a flow passage downstream of the first flow channel 109 leading to an outlet or dispenser or downstream water treating equipment. Further, the first flow channel 109 is dimensioned to provide a flow rate of up to about 2 liters per minute (l / min), and preferably up to 1.6 l / min.

[0163] As shown, the third flow channel 110 is connected to the first flow channel 109 upstream of the valve 106.

[0164] In the manifold for a typical water purification system for laboratory use the second flow channel 108 leading from the second connector 103 to the pressure sensor 105 preferably has a volume of 1 ml or less. Also, in the manifold for a typical water purification system for laboratory use, the third flow channel 110 is preferably dimensioned to provide a flow rate through the third flow channel 110 between 0.02 l / h and 5 l / h.

[0165] For use in such a system the third flow channel 110 is dimensioned to provide a pressure drop of 1 mbar or less when water is filled and / or drained into / from the tank 102 through the first flow channel 109 in order to achieve the desired accuracy of measurement of the water level in the tank.

[0166] Further, for use in such a system, the pressure sensor 105 mounted in the manifold 101 at the downstream end of the second flow channel 108 is configured to allow a measurement of the static pressure in the water tank 102 of between 0 and 150 mbar, preferably between 0 and 30 mbar.

[0167] A schematic representation of an exemplary water purification system 210, which in the present water system corresponds to the post-purification unit, is shown in Figure 5 comprising a pre-purified water feed 211, which in the present water purification system may be seen as corresponding to water tank and post-purification adapter, postpurification unit 212, a feeding line 213 for post-purified water and a dispenser 18, 214 for the post-purified water.

[0168] The preferred feeding line for post-purified water that fixedly (and liquid tightly) connects the post-purification unit and the dispenser as is preferably used herein is now described in more detail by reference to Figures 6a, 6b, and 6c.

[0169] Figure 6a schematically shows an exemplary integral multi-lumen tubing 220, which may be used herein, comprising a total of five lumens 221 separated from each other, with one central lumen 221a and four peripheral lumens 221b symmetrically arranged around the central lumen 221a.

[0170] Figure 6b schematically shows the exemplary integral multi-lumen tubing 220 of Figure 6a with a sheath 222 tightly surrounding the integral multi-lumen tubing 220.

[0171] Figure 6c schematically shows the exemplary integral multi-lumen tubing 220 of Figure 6a with a sheath 222 loosely surrounding the integral multi-lumen tubing 220, thus having a free volume 223 between the sheath and the integral multi-lumen tubing 220.

[0172] The preferred valve assembly comprised in the dispenser of the present water purification system is now described in more detail by reference to the attached exemplary schematic drawings Figure 5 and Figures 7 through lla / llb.

[0173] The valve assembly (240) for a liquid dispenser 231 comprises a pair of first 241 and second discs 242 (see Figure 7 and Figure 8, respectively) to be rotated relative to each other with mutually facing first 241a and second sealing contact surfaces 242a arranged to at least partly slide in contact with each other.

[0174] The first disc 241 has at least one window 243a, 243b (two in the embodiment at positions opposite to each other through the center of the disc). The second disc 242 has a solid portion 244a, 244b arranged to completely cover and thus to close in an axial direction the at least one window 243a, 243b of the first disc 241 in a fully closed rotational position (shown in Figure 9), and an opening portion 245a, 245b arranged to at least partially expose the at least one window 243a, 243b of the first disc 241 upon relative rotation in a progressing manner until it is positioned in a fully open rotational position. Here, too, two solid portions 244a, 244b and two opening portions 245a, 245b are provided in the embodiment complementary to the two windows 243a, 243b of the first disc 241.

[0175] While two of the windows and corresponding opening portions and solid portions are provided in a rotationally symmetrical manner, the number can be one each or more than two distributed about a circumference.

[0176] The windows 243a, 243b extend through the thickness of the first disc 241 in the axial direction and serve as flow paths for the fluid through the valve assembly 240 in the axial direction as described later.

[0177] The solid portion(s) 244a, 244b of the second disc 242 that is / are arranged to completely cover and thus to close the window(s) 243a, 243b of the first disc 241 in the fully closed rotational position is / are formed so as to include a portion of the second sealing contact surface 242a that overlaps the first sealing contact surface 241a of the first disc 241 within a closed sealing zone 246a, 246b, respectively surrounding an edge 243c, 243d of the window(s) 243a, 243b. The sealing zone 246a, 246b has a width of at least 1.5 mm, preferably at least 2.0 mm, measured perpendicularly to the edge or more precisely perpendicularly to a tangent to the edge within the planes of the first and second sealing contact surfaces 241a, 242a to guarantee sealing in the fully closed position (see Figure 9). Sealing with the receptacle of a housing of a dispenser 231 in which the valve assembly 241 is integrated is achieved on the surface opposite to the first sealing contact surface 241a of the first disc 241 (which may be the lower surface of the first disc if arranged as the lower disc in the example of Figure 10) and therefore requires a certain circular area on the outside of the surface with no openings. These two requirements combined with the need to maximize the opening area of the windows 243a, 243b to set a desired maximum dispensing rate as defined above determine the sizes and shapes and features of the two discs 241, 242.

[0178] The first disc 241 and / or the second disc 242 are preferably made of a ceramic material. As the valve assembly 240 is particularly intended to be integrated in a dispensing device and dispenser 231 for ultrapure water, the type of ceramic material used is to be selected to avoid any contamination to the ultrapure water. Aluminum oxide ceramic is a suitable and preferred material. However, depending on the circumstances and if the required sealing properties of the sealing contact surfaces 241a, 242a of the discs can be realized, another material including metal or alloys or a different base material with a suitable coating including a ceramic coating are possible.

[0179] The first disc 241 in the embodiment has a circular outer periphery and the second disc 242 has a non-circular outer periphery with the opening portion 245a, 245b arranged to at least partially expose the at least one window 243a, 243b of the first disc 241 radially recessed from the outer periphery (see Figure 8). The discs 241, 242 may, however, have a peripheral shape other than circular. If the peripheral shape is "not round", it may facilitate holding at least one disc (i.e. the stationary disc) in a receptacle of a dispenser 231 to prevent rotation by engagement with a suitable corresponding shape of a recess or a protrusion.

[0180] The first disc 241 is provided with positioning notches 247a, 247b at an outer periphery for preventing - in a mounted state in a receptacle 232 of the dispenser 231 as shown in Figure 10 - a rotation and for defining a unique mounting position in the receptacle 232. The positioning notches 247a, 247b are formed and / or arranged asymmetrically about a circumference of the first disc 241 in order to define the unique mounting position.

[0181] The second disc 242 is provided with one or more driver recess / recesses 248a, 248b and / or protrusion / protrusions (not shown) on a side opposite to the second sealing contact surface 242a in the axial direction, for engagement with a rotary actuator 233 of the liquid dispenser 231. In the embodiment the recesses 248a, 248b are shallow pockets or grooves with a closed bottom that do not extend through the thickness of the second disc 242 in the axial direction. The rotary actuator 233 is provided with matching protrusions 233a, 233b (see Figure 10) for engaging with the recesses 248a, 248b. The shape or contour of the recesses 248a, 248b and matching protrusions 233a, 233b is unsymmetrical in order to define a unique mounting orientation or more precisely a defined rotation position of the actuator 233 where the engagement is possible. The sealing properties of the discs 241, 242 depend mainly on the percentage of the sealing contact surfaces 241a, 242a of the discs that are effectively in contact at the microscopic level. The disc sealing contact surfaces 241a, 242a are therefore processed to reach a pre-set percentage of the surfaces in contact between the two discs 241, 242. A percentage that is too low would compromise sealing, and a percentage too high would cause excessive efforts of operation. As there are no external forces applied on the discs 241, 242 in the integration in the dispenser 231 as described below, this percentage of the disc surfaces 241a, 242a in contact, together with the water pressure and the friction forces of the seal on the driving actuator 233, are the only parameters that influence the operation efforts.

[0182] The first and second sealing contact surfaces 241a, 242a of the pair of first and second discs 241, 242 that are arranged to at least partly slide in contact with each other have a surface quality or surface roughness Ra of at most 0.60 pm, more preferably of at most 0.50 pm, most preferably of at most 0.40 pm, and / or a flatness of at most 0.80 pm, preferably of at most 0.70 pm, most preferably of at most 0.60 pm, to create the fluid- tight sealing upon contact. Preferably the first and second sealing contact surfaces 241a, 242a of the pair of first and second discs 241, 242 are polished or ground.

[0183] The mutually facing first and second sealing contact surfaces 241a, 242a of the pair of first and second discs 241, 242 are arranged such that a percentage of 50-80%, preferably 55- 75%, and most preferably 60-70% of the first and second sealing contact surfaces 241a, 242a are sliding in contact with each other between the fully closed rotational position and the fully open rotational position.

[0184] The forces required to operate the valve assembly 240 are directly proportional to the axial forces applied to the discs 241, 242:

[0185] Friction forces = normal forces * friction coefficient

[0186] Since the valve assembly is to be integrated in a water dispenser 231, for example in the form of an ergonomic, easy to use dispenser that the user will hold with just one hand and operate with his thumb within a relatively small angular moving range, low operation forces are critical. This differs from similar fluid valves that are driven by a motor or ones where a full hand is used to operate the valve, on a large angular range. It is therefore critical to reduce as much as possible the force required to open and close the valve assembly 240, for ergonomic operation. To that effect, the axial forces that apply to the discs 241, 242 are to be minimized in order to limit the friction forces between the discs 241, 242 to a minimum. Extensive tests showed that water pressure generally is sufficient to press the discs 241, 242 together and achieve sealing, with no additional forces required.

[0187] In the integration of the valve assembly 240 in a dispenser 231 as exemplified in Figure 10, the second disc 242 is arranged as an upper disc and is preferably mounted freely floating in contact with the first disc 241 in order to minimize forces of operation of the water dispenser 231. There is an axial stop in an upper manifold to determine and fix the altitude of the first or lower disc 241 and sealing is achieved between the first disc 241 and the housing with a custom seal 237a, shown in Figure 10. There is then a functional gap between the driving actuator 233, i.e. of the protrusions 233a, 233b in the recesses 248a, 248b of the second disc 242, to guarantee that no axial forces - other than those resulting from the pressure of the fluid acting on the second disc 242 and pressing it against the first disc 241 - are applied between the discs (241, 242).

[0188] Reduced forces and improved ergonomics of operation can also be achieved not only by the optimization of the disc properties and the integration with the freely floating second or upper disc 242, but also by an optimization of the rotating seal on the driving actuator 233.

[0189] In certain applications it might be beneficial, to enhance the sealing effect, to slightly bias the second disc 242 towards the first disc 241, by a biasing member (not shown), for example an elastic member like an elastic seal (for example an O-ring) or spring arranged between the driving actuator 233 and the upper surface of the second disc 242. Such biasing member could, for example, be arranged in the space between the protrusions 233a, 233b and the upper surface of the second disc 242 (not shown in the drawing).

[0190] For the intended use in a liquid dispenser 231 for ultrapure water the disc design and the disc properties are optimized to enable a wide range of flowrates: good sealing must be achieved in the fully closed position and flowrates from stable and easy to reach dropwise dispensing up to the maximum dispensing rate as defined herein when the valve assembly 240 is fully open, with limited pressure drops being provided on a limited ergonomic angular range that allows operation when the liquid dispenser 231 is to be used with just one hand and operated with the thumb, while the rest of the hand holds the device. The discs 241, 242 of the valve assembly 240, in particular the dimensions and arrangement of the window(s) 243a, 243b, of the solid portions 244a, 244b and of the opening portions 245a, 245b are thus configured to provide a rotational angular range between the fully closed rotational position and the fully open rotational position to be between 50°-70°, preferably 55°-65°, and most preferably about 60°.

[0191] The valve assembly 240 is dimensioned so as to provide, within the rotational angular range of the relative movement between the fully closed rotational position and the fully open rotational position, a flowrate through the at least one window (243a, 243b) from dropwise, preferably 20 mL / min, up to the maximum defined dispensing rate as defined herein.

[0192] To in particular provide the stable and easy to reach dropwise dispensing from the fully closed position at the beginning of the operating range (or, though in the following not directly described, correspondingly from the fully open position towards the end of the operating range) the at least one window 243a, 243b of the first disc 241 has a notch / dent 243e recessed into the material of the first disc 241 from the plane defined by the first sealing contact surface 241a of the first disc 241 at an / the edge 243c, 243d of the at least one window 243a, 243b that is located at a side where the exposure of the at least one window 243a, 243b starts upon movement of the second disc (242) from the fully closed rotational position in the direction towards the fully open rotational position (see Figures 7, 9, and lib). Preferably, only one of the windows 243a, 243b of the first disk 241 has a notch / dent 243e. Nevertheless, depending upon specific requirements both windows 243a, 243b or - if disk 241 has more than two windows - any number of these may have such a notch / dent.

[0193] The notch / dent 243e has a pointed sharp tip that gradually and continuously widens in a horizontal direction defined by the extension of the plane of the first sealing contact surface 241a and / or deepens gradually towards the at least one window 243a, 243b in the direction perpendicular to that plane. In other words, the surface of the cross section of the notch / dent 243e increases towards the at least one window 243a, 243b in the circumferential direction of the first disc 241.

[0194] Further, to smoothen the flow of the liquid upon further rotation of the second disc 242 beyond the range of the notch / dent 243e, the at least one window 243a, 243b has an inclination or ramp 243f at a sidewall adjacent to the side where the exposure of the at least one window 243a, 243b starts upon movement of the second disc 242 from the fully closed rotational position in the direction towards the fully open rotational position such that the free opening width or surface of the cross section of the at least one window 243a, 243b in the thickness or axial direction of the first disc 241 becomes gradually narrower over at least a certain range with distance from the plane of the first sealing contact surface 241a.

[0195] As mentioned before the present valve assembly 240 is in particular designed and advantageous for use in a liquid dispenser 231 for a water purification system. The integration of the valve assembly 240 in a preferred embodiment of a liquid dispenser 231 is at least partially shown in the cross-sectional view of Figure 10. The liquid dispenser 231 that is in the form of an ergonomic, easy to use dispenser to be held by a single hand of a user while the valve assembly 240 is operated by the thumb comprises a housing 235, a supply piping 236 for purified water connected to a port 239 of the housing 235 directed towards the upper side, and an outlet 238 for purified water directed towards the lower side in a typical upright held orientation.

[0196] The present valve assembly 240 is arranged in a receptacle 232 of a housing 235 such that the valve assembly 240 can control the volume or rate of the flow of purified water from the supply piping 236, i.e. an integral multi-lumen tubing as defined herein, to the outlet 238. The receptacle 232 is in communication with the port 239 of the housing 235 and the outlet 238.

[0197] The first disc 241 of the valve assembly 240 is rotationally fixed in position within the receptacle 232, for example by protrusions engaging with the positioning notches 247a, 247b at the outer periphery of the first disc 241 (see Figure 7) or by the mating shape of the receptacle such that the at least one window 243a, 243b communicates with the outlet 238. The outer periphery of the surface of the first disc 241 surrounding the lower opening of the window(s) 243a, 243b is sealed against the housing 235 by means of an annular seal 237a such that all liquid entering the outlet 238 from the receptacle 232 must pass through the window(s) 243a, 243b of the fist disc 241.

[0198] The second disc 242 is shown to be mounted in the receptacle 232 so as to freely float in contact with the first disc 241 and such that the first and second sealing contact surfaces 241a, 242a are pressed against each other by only the water pressure from the supply piping 236 acting on the second disc 242 as described above. The second disc 242 of the valve assembly 240 is engaged with a manually operable rotary actuator 233, 234 for rotatingly driving the second disc 242 relative to the first disc 241 between the fully closed rotational position and the fully open rotational position within the above described rotational range. The rotary actuator comprises an axle 234 and a driver 233 connected with a lower end of the axle 234.

[0199] Though driver 233 and axle 234 may be made (i.e. essentially consists) of the same material, it is preferred that driver 233 and axle 234 are made of different materials. Preferably, driver 233 is made of (i.e. essentially consists) of a material that has a low content of leachables, i.e. has a low tendency to release contaminants. Non-limiting examples of materials suitable for driver 233 may be selected from the group consisting of polyacetal, and polypropylene. A preferred example of a material suitable for driver 233 is polyoxymethylene (POM). Preferably, axle 234 is made of a material having good mechanical strength, especially on torsion resistance, so as to allow for accurate and precise operation of the ceramic discs, which is particularly necessary to find the dropwise dispensing position. Non-limiting examples of such materials suitable for axle 234 may be selected from the group consisting of polyamides (PA), reinforced (e.g. with fiber reinforcement or talc) polyamides, and reinforced (e.g. with talc) polypropylene. A preferred example of a material suitable for axle 234 is polyphthalamide (PPA).

[0200] A part of the actuator, not shown in the drawing, extends to the outside of the housing 235 and is accessible for the thumb of the hand to be operated to rotationally drive the second disc 242 and can be shaped according to the desired ergonomics. The rotary actuator is sealed against the housing 235 by an O-ring or gasket 237b to prevent liquid from escaping the receptacle 232 other than through the outlet 238. The specific design of the actuator is not critical provided the floating positioning and contact of the second disc against the first disc is achieved without introducing additional axial forces in connection with the operation for rotation of the second disc from the fully closed to the fully open rotational position (see also Figures 11a and lib).

[0201] In the embodiment the second disc 242 is provided with additional protrusions 244c, 244d on an outer periphery that are inserted into corresponding peripheral grooves 232a, 232b of the receptacle 232 so as to guide and limit the rotational range of the rotation of the second disc 242.

[0202] In addition to the considerations regarding hydraulic performance and usability, the shapes and features of the two discs 241, 242 are also optimized for a simple and robust assembly process, with very limited possibilities to misassemble (i.e. wrongly assemble) the parts in the housings 235 of the liquid dispenser 231 dispenser. In particular, the positioning notches 247a, 247b on the first disc 241 used to maintain the first disc 241 in place are not symmetrical, so as to only fit in one position into the receptacle 232 in which it is integrated. The asymmetrical ribs 232c, 232d in the receptacle 232 that are used to maintain the first or lower disc 241 in a fixed position also prevent the upper disc 242 to be mounted in the wrong angular position (see Figures 11a and lib).

[0203] The two protrusions 233a, 233b (see Figure 10) for engaging with the recesses 248a, 248b in the second or mobile disc 242 used to drive valve operation with the rotating actuator 233, 234 are also different from each other, to allow only one angular position relative to an axis of the actuator 233. This is important as the stops on the valve (fully open and fully closed) are defined between the axle and the housing 235. Ribs 232e, 232f between the peripheral grooves 232a, 232b of the receptacle 232 are used for defining these stops and thus also influence the outer shape of the second or mobile disc 242 that should be free to rotate on its operating range despite these ribs 232e, 232f.

Claims

Claims1. System (1) for providing ultrapure water (2) for laboratory applications, comprising at least one water connection (5) for supplying the system (1) with feed water (4) to be purified, at least one pre-purification unit (3) fixedly connected to the at least one water connection (5) for pre-purifying the feed water (4) to produce prepurified water (13), at least one post-purification unit (15) for post-purifying the prepurified water (13) to produce post-purified water (19), and at least one water tank(12), said system (1) is characterized in that the at least one pre-purification unit (3) is fixedly connected to a pre-purification adapter (11), the pre-purification adapter (11) for detachably connecting a water tank (12) for receiving the pre-purified water(13) from the pre-purification unit (3), and the at least one post-purification unit (15) is fixedly connected to a post-purification adapter (14), the post-purification adapter(14) for detachably connecting a water tank (12) for supplying the pre-purified water (13) to the at least one post-purification unit (15), and in that the pre-purification adapter (11) and the post-purification adapter (14) are similarly configured for sequentially connecting with one and the same water tank (12), preferably wherein the feed water (4) is tap water.

2. The system (1) according to claim 1, characterized in that the pre-purification unit (3) and the pre-purification adapter (11) on the one hand side and the postpurification unit (15) and the post-purification adapter (14) on the other hand side are spatially separated.

3. The system (1) according to claim 1 or claim 2, characterized in that the pre-purification adapter (11) and the postpurification adapter (14) each comprises a closure for forcibly closing a connection for the flow of pre-purified water (13) therethrough when not connected to the water tank (12) and / or that the pre-purification adapter (11) and / or the postpurification adapter (14) comprises a seal for sealing a connection for the flow of pre-purified water (13) therethrough when connected to the water tank (12); and / or characterized in that the pre-purification adapter (11) and the postpurification adapter (14) are adapted to attach a water tank (12) from above and to join a connection for flowing pre-purified water (13) therethrough by mounting the water tank (12) on the pre-purification adapter (11) and the post-purificationadapter (14), and that, preferably, the pre-purification adapter (11) and the postpurification adapter (14) are designed to form a frictional and / or positive connection with the water tank (12) by placing the water tank (12) onto the prepurification adapter (11) and the post-purification adapter (14).

4. The system (1) according to any one of the preceding claims, characterized in that the pre-purification adapter (11) and the post-purification adapter (14) comprise manifold (101) for a water tank (12, 102), the manifold (101) in turn comprising: a first flow channel (109) for filling and / or draining the liquid into / from the tank (12, 102); a second flow channel (108) for guiding the liquid in the tank (12, 102) to a pressure sensor (105) mounted in the manifold (101) so as to allow a measurement of the static pressure in the liquid tank (12, 102); and a third flow channel (110) connecting the first flow channel (109) and the second flow channel (108), wherein the third flow channel (110) is configured and arranged to replace stagnant water in the second flow channel (108) when liquid is filled and / or drained into / from the tank (12, 102) through the first flow channel (109).

5. The system (1) according to any one of the preceding claims, characterized in that the pre-purification unit (3) comprises one or more selected from the group consisting of a reverse osmosis unit with at least one semi- permeable membrane, an electro-deionization unit with at least two electrodes, an activated carbon unit with at least one activated carbon, in particular an activated carbon filter, an ion exchanger unit with at least one ion exchanger resin, a filtration unit, and any combination of any of these; preferably characterized in that the pre-purification unit (3) comprises one or more selected from the group consisting of a reverse osmosis unit with at least one semipermeable membrane, an activated carbon unit with at least one activated carbon, in particular a carbon filter, an ion exchanger with at least one ion exchanger resin, a filtration unit, and any combination of any of these; and more preferably characterized in that the pre-purification unit (3) comprises one or more selected from the group consisting of a reverse osmosis unit with at least one semipermeable membrane, an activated carbon unit with at least one activated carbon filter, a filtration unit, and any combination of these.

6. The system (1) according to any one of the preceding claims, preferably characterized in that the pre-purification unit (3) comprises, preferably in sequence from the water connection (5) to the tank (12), an optional first pre-purification sub-unit (7), and a second pre-purification sub-unit(8), wherein the first pre-purification sub-unit (7) - if present - comprises an activated carbon filter and / or a depth filter; and wherein the second pre-purification sub-unit (8) is a reverse osmosis unit; preferably characterized in that the pre-purification unit (3) comprises, preferably in sequence from the water connection (5) to the tank (12), an optional first pre-purification sub-unit (7), and a second pre-purification sub-unit(8), wherein the first pre-purification sub-unit (7) - if present - comprises an activated carbon filter and / or a depth filter selected from pleated filters and depth filtration units; and wherein the second pre-purification sub-unit (8) is a reverse osmosis unit.

7. The system (1) according to any one of the preceding claims, characterized in that the post-purification unit (15) comprises one or more selected from the group consisting of an ion exchanger unit with at least one ion exchanger resin for separating ions, an activated carbon unit with at least one activated carbon for separating organic components, at least one UV unit with at least one UV lamp, and any combination of any of these.

8. The system (1) according to any one of the preceding claims, characterized in that the system (1) comprises at least one water tank (12) connected to at least one of the pre-purification adapter (11) and the post-purification adapter (14), and at least one water tank (12) connected to at least one of the pre-purification adapter (11) and the post-purification adapter (14), and that, preferably, the at least one water tank (12) comprises a closure for forcibly closing a connection for the flow of prepurified water (13) therethrough when not connected to the pre-purification adapter (11) or the post-purification adapter (14) and / or the water tank (12) comprises a seal for sealing a connection for the flow of pre-purified water (13) therethrough from the pre-purification adapter (11) and / or into the postpurification adapter (15).

9. The system (1) according to any one of the preceding claims, characterized in that the at least one water tank (12) comprises a handle (24) for carrying the water tank (12),and / or that the water tank (12) is at least partially formed of a transparent plastic; and / or at least two water tanks (12) of similar, in particular identical, design are provided and are connected to the at least one pre-purification adapter (11) and / or the at least one post-purification adapter (14).

10. The system (1) according to any one of the preceding claims, characterized in that it further comprises a dispenser (18) fixedly connected to the at least one postpurification unit (15) for dispensing post-purified water (19), preferably wherein the dispenser (18) is designed for manual dispensing of post-purified water (19) in form of a handset dispenser and that, preferably, the dispenser (18) comprises a manually operable adjustment device for adjusting the flow rate, and / or preferably wherein the dispenser (18) comprises a valve assembly (10) for a liquid dispensing unit (1) comprising: a pair of first and second discs (241,242) to be rotated relative to each other with mutually facing first and second sealing contact surfaces (241a, 242a) arranged to at least partly slide in contact with each other, wherein the first disc (241) has at least one window (243a, 243b), and wherein the second disc (242) has a solid portion (244a, 244b) arranged to completely cover to close the at least one window (243a, 243b) of the first disc (241) in a fully closed rotational position, and an opening portion (245a, 245b) arranged to at least partially expose the at least one window (243a, 243b) of the first disc (241) in a fully open rotational position.

11. The system (1) according to any one of the preceding claims, characterized in that the post-purification unit (15) and the dispenser (18, 214) are fixedly connected to each other by a feeding line (213) for post-purified water, wherein the feeding line (213) comprises an integral multi-lumen tubing (220), the integral multi-lumen tubing (220) comprising at least two separate lumens (221) serving as flow paths for feeding water to and from the dispenser (18, 214), respectively.

12. A laboratory (20) comprising at least one system (1) according to any one of claims 1 to 11,-M - preferably a laboratory (20) comprising at least one system (1) according to any one of claims 1 to 11, characterized in that the laboratory comprises more postpurification units (15) than pre-purification units (3), preferably at least twice as many post-purification units (15) than pre-purification units (3), further preferably at least three times as many post-purification units (15) than pre-purification units (3), in particularfourtimes as many post-purification units (15) than pre-purification units (3), and in that, preferably, the post-purification units (15) are arranged at different laboratory workplaces (22), in particular on different laboratory benches (23).

13. A method of operating a system (1) according to any one of claims 1 to 11, in particular in a laboratory (20) according to claim 12, wherein feed water (4) is supplied via the water connection (5) to the at least one pre-purification units (3) and is pre-purified in the pre-purification units (3) to produce pre-purified water (13), wherein the pre-purified water (13) is fed into a water tank (12) via a prepurification adapter (11), wherein the water tank (12), at least partially filled with pre-purified water(13), is separated from the pre-purification adapter (11), moved manually to the post-purification adapter (14) and connected to the post-purification adapter (14), wherein the pre-purified water (13) is fed from the water tank (12) to the postpurification unit (15) via the post-purification adapter (14) and is post-purified in the post-purification unit (15) to produce post-purified water (19), and optionally wherein the post-purified water (19) is dispensed via a dispenser (18) fixedly connected to the post-purification unit (15).

14. The method according to claim 13, wherein the pre-purified water (13) is fed into another water tank (12) via a pre-purification adapter (11), wherein the further water tank (12) at least partially filled with pre-purified water (13) is separated from the pre-purification adapter (11), moved manually to a further post-purification adapter (14) and connected to the further post-purification adapter (14), wherein the pre-purified water (13) is fed from the further water tank (12) into the further post-purification unit (15) via the further post-purification adapter(14) and is post-purified in the further post-purification unit (15) to produce postpurified water (19), andoptionally, wherein the post-purified water (19) is dispensed via a dispenser (18) fixedly connected to the further post-purification unit (15).

15. The method according to claim 13 or 14, wherein a closure of the water tank (12) and of the water tank connection of the pre-purification unit (3) is forced from an open state to a closed state when the water tank (12) is disconnected from the pre-purification adapter (11) and / or wherein a closure of a connection of the water tank (12) and of the water tank (12), the pre-purification adapter (11) and the post-purification adapter (14) is forced from a closed state to an open state when the water tank (12) is connected to the post-purification unit (15) and / or wherein the pre-purification adapter (11), the water tank (12) and / or the postpurification adapter (14) comprises a seal for sealing a connection for the flow of pre-purified water (13) in the state of the pre-purification adapter (11) and / or the post-purification adapter (14) connected to the water tank (12).

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