EP3712512A1 - Device and method of supplying warm drinking water - Google Patents

Abstract

Device for the provision of warm drinking water with a hot water inlet (5) leading from a hot water heater (1) to at least one extraction fitting (6) and a circulation line (7) - preferably provided with a circulation pump (8) - from the area of the extraction fitting back to the hot water heater ( 1), with a water treatment device (9) which is connected to the circulation line (7) and which has at least one filter (13) and via which at least a partial flow of water is led out of the circulation line (7) and then back downstream into it, wherein the water treatment device (9) has at least one limescale protection device (14).

Description

The invention relates to a device for providing warm drinking water according to the preamble of claim 1. Furthermore, the invention relates to a water treatment device for such a device and a method for treating warm drinking water according to the preamble of claim 17.

With hot water supply systems there is a risk that biomass deposits and germs form at the warm water temperatures. These germs can also include pathogens, particularly legionella, which are harmful to health. For this reason, it has hitherto often been suggested that the water temperature be heated above a certain value, for example 60 ° C., in order to stop the formation of harmful germs or to destroy such germs. However, heating to high temperatures also has disadvantages. On the one hand, the energy requirement is very high, on the other hand, you often only have lower temperatures from solar systems or other systems with heat pumps.

It has also already been proposed to arrange filters in the circulation line or parallel to it in order to remove any germs and other biomass that may have formed from the water and thus to reduce the harmful substances, in particular the number of dangerous germs. Such prior art is for example in DE 10 2017 101 532 A1 described.

The object of the invention is to provide an improved device for providing warm drinking water, a suitable water treatment device and a corresponding method with which it is possible to prevent the formation of germs, particularly harmful ones, even at relatively low hot water temperatures (preferably below 60 ° C) Legionella and / or curb or completely suppress the deposition of biomass.

According to the invention, this is achieved by the features of claims 1, 35 and 37.

The basic idea of the invention is to use a combination of filter and limescale protection device to achieve a synergistic effect and thus to greatly reduce or completely prevent the deposition of biomass and / or the multiplication of germs, especially legionella, which is harmful to health, in drinking water even if the drinking water temperature is below 60 ° C. The limescale protection device can prevent or at least reduce the formation of limescale deposits on the surfaces of water-bearing elements, so that these surfaces remain smooth and thus the accumulation and formation of biomass and / or germs is reduced or completely prevented. This also applies in particular to the system or nucleation in the filter itself. Conversely, due to the filter, less biomass and / or other suspended matter accumulate on the active surfaces of the limescale protection device, which means that it can work effectively for a long time. Limescale protection device and filter thus help each other in the sense of a synergy effect.

Overall, a reduction in biomass and / or other accumulations can thus be achieved and thus harmful germs can be reduced - be it through direct filtering out or through "starvation" by removing biomass or other contact points that would otherwise encourage germ formation.

In particular, physically operating limescale protection devices that work on the principle of heterogeneous catalysis can be used as limescale protection devices. Such a limescale protection device has a modified, weakly acidic ion exchange material for catalytic lime precipitation, preferably in the Ca form, as a water-treated substance.

However, other limescale protection devices can also be used. For example, those that work by adding antiscalants, especially phosphates, or those that work on the principle of ion exchangers ^and exchange hardness-forming ions such as Ca ²⁺ and Mg ^2+, for example for Na ⁺ . The water is really softened in the chemical sense through the exchange of ions. In the case of the heterogeneous catalysis described above, no ion exchange takes place during the lime precipitation. Rather, this takes place catalytically.

There is also the possibility of using electro-physical processes or other processes by which the limescale protection device is operated.

As far as the filter is concerned, it preferably has a membrane whose pore size is below 0.2 µm, preferably below 0.1 µm. Such filters are also known as ultrafiltration filters. In particular, they can have membranes made of organic material and / or of ceramic material.

In general, the membrane will be built up asymmetrically with a carrier layer (for example fleece), a porous support layer and the actual filtering membrane on top. However, other structures of membranes are also quite conceivable and possible.

The advantage of using ceramic membranes is that they have a well-defined pore structure. They can also be completely freed from organic residues by "annealing" without suffering as a result. They can therefore be recycled for a long time.

Overall, ceramic membranes have a high temperature resistance and high material compatibility when used in drinking water.

Using the preferred ultrafiltration, numerous substances can be removed from drinking water, including biomass, bacteria, viruses, colloids, etc.

Even if the combination according to the invention of the filter with a limescale protection device prevents the filter from clogging due to the build-up of limescale, the filter is generally clogged with the substances to be filtered out over a certain period of time. The filter can therefore preferably be regenerated, preferably without removing it, by simply flushing it. Either in the normal forward direction or by reversing the direction of flow. An electronic control device can also regulate this backwashing or flushing automatically via the filter as a function of system parameters, such as the pressure drop, for example.

It is also possible for this electronic control device to control a so-called thermal disinfection cycle in which the filter and the limescale protection device are at least temporarily brought to an elevated temperature, namely above 60 ° C, preferably above 75 ° C. For this purpose, a heating device is provided, which can also preferably be formed in the limescale protection device itself.

Suitable pipes and valves can be used to ensure that both elements, namely the limescale protection device and the filter, are effectively traversed by hot water and thus successfully disinfected in order to completely eradicate the germs reduced by the measure according to the invention.

Fig. 1

ein Ausführungsbeispiel einer erfindungsgemäßen Einrichtung zur Bereitstellung von warmem Trinkwasser mit einer Zirkulationsleitung und einem Ausführungsbeispiel einer erfindungsgemäß ausgebildeten Wasserbehandlungseinrichtung,

Fig. 2

Alternative eines Ausführungsbeispiels einer erfindungsgemäßen Wasserbehandlungseinrichtung,

Fig. 3

eine weitere Alternative,

Fig. 4

eine weitere Alternative,

Fig. 5

detailliertere, schematische Darstellung eines weiteren Ausführungsbeispiels einer erfindungsgemäßen Wasserbehandlungseinrichtung, und

Fig. 6

Ausführungsbeispiel einer Kalkschutzeinrichtung mit Heizung.

Further advantages and details of the invention are explained in more detail with reference to the following description of the figures. To show:

Fig. 1

an embodiment of a device according to the invention for providing warm drinking water with a circulation line and an embodiment of a water treatment device designed according to the invention,

Fig. 2

Alternative of an embodiment of a water treatment device according to the invention,

Fig. 3

another alternative,

Fig. 4

another alternative,

Fig. 5

more detailed, schematic representation of a further exemplary embodiment of a water treatment device according to the invention, and

Fig. 6

Embodiment of a limescale protection device with heating.

In the Fig. 1 The device shown for providing warm drinking water has a water heater 1 which has a warm water heating device 2 and a heat exchanger 3. The hot water heating device 2 can also be arranged in a decentralized manner (district heating).

The heat exchanger 3 heats the drinking water fed in via the cold water inlet, which is then fed to an extraction fitting 6 via the hot water inlet 5. In general, there are numerous tap fittings in the building. In Fig. 1 For the sake of simplicity, only one extraction fitting 6 is shown as an example.

From the extraction fitting 6, a circulation line 7 with a circulation pump 8 leads back to the inlet of the heat exchanger 3. When the extraction fitting 6 is closed, a small flow of water flows back to the heat exchanger 3 via the circulation line 7, so that water at a high temperature is always available in the entire line system 5, 7 stands, so that when opening the extraction fitting 6 one does not have to wait long until any cooled water can be withdrawn from the hot water flow.

A water treatment device, generally designated "9", is connected to the circulation line. An inlet connection 10 and an outlet connection 11 are then provided. Valves 12, which are electronically controllable in particular by a control device (not shown), can be used to easily regulate how much water is currently flowing through the circulation line and how much water is flowing through the water treatment device 9. It is possible to take a partial flow from the circulation line or, in certain operating states, to route all of the water in the circulation line via the water treatment device.

According to the invention, the water treatment device 9 has a filter 13 (in this exemplary embodiment an ultrafiltration filter UF) and a limescale protection device 14, KS. In addition, a device 15, TD for thermal disinfection is also provided. Material that has been flushed out during a flushing process of the filter 13 can reach a drain 17 via a flushing drain line 16.

The Fig. 2 shows a first variant of how the individual components within the water treatment device 9 are flowed through by the partial flow of the drinking water in the circulation line. In the in Fig. 2 The exemplary embodiment shown is flowed through in series through the limescale protection device and the filter designed as an ultrafiltration filter, it also being possible to arrange the ultrafiltration filter 13 upstream of the limescale protection device 14 in the direction of flow. The ultrafiltration filter 13 can be backwashed for cleaning purposes via a backwash line 18, the contaminated rinsing water being discharged via the lines 16, 17.

The limescale protection device itself can contain a preferably granular ion exchange material and, for example, be designed as the EP 0 957 066 B1 shows.

In particular, it is possible that the limescale protection device has a modified, weakly acidic ion exchange material for catalytic lime precipitation, which is preferably present in the Ca form as a water-treating substance. The use of chemical treatment substances and thus the contamination of drinking water can be prevented by catalytic precipitation. An embodiment is particularly preferred in which the ion exchange material has functional groups on its surface which are charged with counter-ions, the counter-ions preferably being cations and in particular Ca ²⁺ ions. Functional groups which contain carboxylate are suitable as weakly acidic ion exchange material.

As already mentioned, other limescale protection devices can also be used.

The filter 13 is preferably constructed as an ultrafiltration filter which has at least one membrane, which is preferably arranged in a tubular shape and is flowed through from the inside to the outside.

The pore size of the ultrafiltration filter or the membrane (membranes) arranged therein is below 0.2 μm, preferably below 0.1 μm.

As far as the separation limit (Molecular Weight Cut Off, MWCO) is concerned, this is between 1 kDa and 200 kDa for the preferred ultrafiltration filter.

• Hohlfaser-Membran, vorzugsweise angeordnet in einem Bündel von mehreren solchen Hohlfaser-Membranen
  und/oder
• Platten-Membran, vorzugsweise angeordnet in einem Stapel aus mehreren hintereinanderliegenden parallelen Platten-Membranen
  und/oder
• als vorzugsweise radial durchströmbare Wickel-Membran und/oder
• als vorzugsweise radial durchströmbare Rohr-Membran.

It is preferably provided that the at least one membrane of the filter is designed as

• Hollow fiber membrane, preferably arranged in a bundle of several such hollow fiber membranes
  and or
• Plate membrane, preferably arranged in a stack of several parallel plate membranes lying one behind the other
  and or
• as a winding membrane through which a flow can preferably flow radially and / or
• as a preferably radially permeable tubular membrane.

The typical transmembrane pressures are between 0.01 bar and 5 bar, preferably between 0.1 bar and 1 bar.

The ultrafiltration filter can also be used to remove the smallest, disruptive contaminations from the water, in particular biomass and other suspended matter, but also directly germs, bacteria and viruses.

So that the filter can be used over a longer period of time, it can be designed to be flushable or backflushable in order to convey the substances retained in the filter to the outside in a flushing process.

Likewise, the limescale protection device 14 can be designed to be flushable or backflushable. The in Fig. 3 A flushing line 20 with a flushing pump 19 is provided, which can lead a partial flow or the entire water flow through the ultrafiltration filter 13 and the limescale protection device 14 for flushing purposes, the flushed substances then reach the drain 17 via the drainage line 16. It is also possible As indicated by small arrows below the ultrafiltration module 13 or the limescale protection device 14, it is possible to backwash these two units, that is, to flow through them in the opposite direction to the Rinse out any suspended substances. The flushing line 20 is then to be routed differently accordingly.

This in Fig. 4 The illustrated embodiment differs from the embodiment of FIG Fig. 3 essentially in that a device TD, 15 for thermal disinfection is integrated in the limescale protection device 14, as will be done later on the basis of FIG Fig. 5 will be described in more detail. An electronic control device (not shown in FIG.) Can control the multi-way valve 21 in such a way that essentially the entire flow of liquid is guided via the flushing line 20 when the thermal disinfection cycle is activated.

Via the multi-way valve 21, in cooperation with the valve group 12, backwashing can also take place with line pressure from the cold water line 4 via 7 and 11 into the water treatment unit 9 or with heated water from 4 via 3, 5 and 7 into the water treatment unit 9. The backwash water is conveyed into the drain 17 via 16.

In the Fig. 1 Valves 12 shown, which lead to or from the water treatment device 9, are then preferably blocked during the disinfection cycle. The disinfection cycle can be triggered by various circumstances or parameters, for example by measuring the pressure drop across the filter or the limescale protection device. Time control is also possible. It is also possible to measure flow rates and, depending on this, to disinfect the system. Rinsing or backwashing can also be associated with disinfection. The heating device of the device for thermal disinfection can also be designed separately from the ultrafiltration filter and separately from the limescale protection device. When integrated in the limescale protection device (and / or in the filter), components can be saved and compact designs can be implemented.

This in Fig. 5 The illustrated embodiment shows an embodiment of a water treatment device according to the invention in greater detail. Central components of the water treatment device 9 are again the ultrafiltration filter 13, the limescale protection device 14 with integrated thermal disinfection (heating device 15). In addition, a microfilter 23 is provided which has a larger pore size than the ultrafiltration filter. For example, a pore size greater than 0.1 µm, particularly preferably between 5 µm and 500 µm.

The water treatment device 9 according to Fig. 5 has an electronic control device 100 which, via sensors (not shown), can measure parameters such as pressures or temperatures in the water treatment device, among other things. Flow measurements in certain lines are also possible.

The electronic control device 100 can control the electromagnetic valves 22 as well as the in Fig. 1 control valves 12 shown.

In the Fig. 5 The components shown are surrounded by a housing 30, indicated by dashed lines, which can be designed like a cabinet and preferably has an openable door (not shown).

In normal operation, the in Fig. 5 illustrated embodiment, a partial flow of the drinking water is fed from the circulation line 7 via the inlet connection of the water treatment device 9 and returned from this via the outlet connection 11 of the circulation line 7. During normal operation, the drinking water passes through the microfilter 23 to the ultrafiltration filter 13 and from there into the limescale protection device 14 and from there back to the drain connection 11. Drinking water is thus pre-filtered in the microfilter 23 and ultra-fine-filtered in the ultrafiltration filter 13 and then treated in the limescale protection device 14. The water then passes through the circulation line, which Circulating pump 8, the heat exchanger 3, the hot water flow 5 and the circulation line 7 as well as the inlet connection 10 back into the heat treatment device 9. Overall, the water is therefore continuously circulated, it being sufficient if a partial flow is passed through the water treatment device 9. However, it is also possible to completely close the valve 12 provided directly in the circulation line, with the result that the entire current flows through the heat treatment device. As a result of this normal operation, biomass, other suspended matter and also germs are constantly removed from the drinking water and the drinking water is also constantly treated against lime deposits by the limescale protection device. This makes it possible to prevent the formation of germs and / or legionella bacteria even at low drinking water temperatures of below 60 ° C.

From time to time, however, the water treatment device 9 can still be thermally disinfected. For this purpose, the valves 22 are switched by the electronic control device such that hot water flows from the limescale protection device 14 via a pump 19 through the microfilter 23 and the ultrafiltration filter 13. In principle, the water can be circulated. However, it is also possible to use the water immediately for a flushing process and to supply it to the flushing water line 16 and the drain 17 via appropriate switching of the valves 22.

It is possible to manually rinse and / or disinfect the water treatment unit 9 and in particular its components 13, 14 and 23 and to switch it on. However, it is also possible that system parameters automatically carry out such a flushing or disinfection with the aid of the electronic control 100, for example time-controlled or pressure-controlled, by the pressure drop over certain components, for example the ultrafiltration filter 13 and / or the microfilter 23 and / or the Lime protection device 14 are measured. If the pressure rise above a certain value, the electronic control device starts the valves and to control the pump 19 so that the water carries out a rinsing process or a thermal disinfection process.

This in Fig. 6 The illustrated embodiment shows in detail a limescale protection device 14 with a heating device 23 in the form of a sleeve.

Via an inlet 24, water reaches the outer shell 25 downwards. Granular ion exchange material 28 lies on a sieve 26 and is flowed through from below in the sense of a floating bed. The sequence from the limescale protection device 14 is denoted by 29. The heating sleeve 23 allows the water inside the limescale protection device 14 to be increased to temperatures above 60 ° C, preferably above 75 ° C, especially when there is little flow or when the water is standing still, and thus not only to use this water to disinfect the limescale protection device itself , but also thermal disinfection of connected components, such as the in Fig. 5 Ultrafiltration filter 13 or the microfilter 23 to make.

The invention is of course not restricted to the exemplary embodiments shown. Embodiments with the features of the subclaims but also other embodiments are entirely conceivable and possible.

The invention also relates not only to the entire device, as for example in Fig. 1 is shown, but also to a water treatment device for such a device as shown in Figures 2 to 5 is shown. These can be provided as stand-alone products for connection to existing circulation lines (retrofitting).

The method according to the invention is characterized in that, in order to reduce the biomass in the drinking water, at least a partial flow of the drinking water conveyed in the circulation line via a circulation pump is taken from the circulation line, cleaned using at least one filter, treated using at least one limescale protection device and then the circulation line is returned.

Claims (19)

Device for the provision of warm drinking water with a hot water flow (5) leading from a water heater (1) to at least one extraction fitting (6) and a circulation line (7) - preferably provided with a circulation pump (8) - from the area of the extraction fitting back to the water heater ( 1), with a water treatment device (9) which is connected to the circulation line (7) and which has at least one filter (13) and via which at least a partial flow of water is led out of the circulation line (7) and then back downstream into it, characterized in that the water treatment device (9) has at least one limescale protection device (14). Device according to Claim 1, characterized in that the limescale protection device (14) has a modified, weakly acidic ion exchange material (28) for catalytic lime precipitation, preferably in the Ca form as a water-treating substance. Device according to claim 2, characterized in that the ion exchange material (28) has functional groups on its surface which are charged with counter-ions, the counter-ions preferably being cations and in particular Ca ²⁺ ions and / or that the limescale protection device (14) contains a weakly acidic ion exchange material (28) whose functional groups on the surface are carboxylate (COO ^- ). Device according to one of Claims 1 to 3, characterized in that the filter (13) comprises an ultrafiltration filter (UF). Device according to claim 4, characterized in that the ultrafiltration filter (UF) has a pore size of less than 0.2 µm, preferably less than 0.1 µm, whereby it is preferably provided that the ultrafiltration filter (UF) has at least one membrane with a pore size between 0.002 µm and 0.2 µm, preferably between 0.01 µm and 0.1 µm. Device according to one of claims 1 to 5, characterized in that at least one membrane of the filter (13) is designed as - Hollow fiber membrane, preferably arranged in a bundle of several such hollow fiber membranes
and or - Plate membrane, preferably arranged in a stack of several parallel plate membranes lying one behind the other
and or - As a preferably radially permeable winding membrane and / or - As a preferably radially permeable tubular membrane. Device according to one of Claims 1 to 6, characterized in that the water treatment device (9) - viewed in the direction of flow - has at least two filters (23, 14) of different pore sizes connected in series. Device according to one of Claims 1 to 7, characterized in that a microfilter (23), preferably with a pore size above 0.1 µm and particularly preferably between 5 µm and 500 µm, is provided in addition to the ultrafiltration filter (UF). Device according to one of claims 1 to 8, characterized in that the water treatment device (9) has a device (TD, 15) for having thermal disinfection of components of the water treatment device (9), in particular for thermal disinfection of the limescale protection device and the at least one filter. Device according to one of Claims 1 to 9, characterized in that the device for thermal disinfection (TD, 15) can be switched on temporarily in a disinfection cycle, the water treatment device (9) being preferably hydraulically separated from the circulation device (7) during this disinfection cycle. Device according to one of Claims 1 to 10, characterized in that the device (TD) for thermal disinfection has a heating device (15) by means of which the water can be heated to above 60 ° Celsius, preferably above 75 ° Celsius. Device according to one of claims 1 to 11, characterized in that the device (TD) for thermal disinfection comprises a heating device (15) which is arranged in or on the limescale protection device (14) and by means of which the device located in the limescale protection device (14) Water can be heated. Device according to one of claims 1 to 12, characterized in that an electronic control device is provided which controls the thermal disinfection cycle and / or a rinsing cycle as a function of stored time intervals and / or of the measured pressure difference via at least one filter and / or of measured flow rates controls through at least one filter. Device according to one of Claims 1 to 13, characterized in that the components of the water treatment device (9), in particular the limescale protection device (14) and the at least one filter are combined into a structural unit, which are preferably surrounded by a cabinet-like housing (30). Device according to one of Claims 1 to 14, characterized in that the housing (30) has an inlet connection (10) and an outlet connection (11) which can be connected - preferably detachably - to the circulation line (7). Water treatment device for a device for providing warm drinking water according to one of claims 1 to 15, which - preferably in a common housing (30) - a limescale protection device (14) and at least one filter (13), as well as an inlet connection and an outlet connection for connection has a circulation line. A method for treating warm drinking water in a device for providing drinking water, characterized in that, in order to reduce the biomass in the drinking water, at least a partial flow of the drinking water conveyed in the circulation line via a circulation pump is taken from the circulation line and cleaned by means of at least one filter, is treated by means of at least one limescale protection device and is then returned to the circulation line. A method according to claim 17, characterized in that the removed water can be heated via a device for thermal disinfection, preferably above 60 ° and particularly preferably above 75 ° Celsius. Method according to claim 17 or 18, characterized in that during the heating of the water in the water treatment device, the hydraulic connection to the circulation line is interrupted and the heated water within the water treatment device itself - preferably via at least one circulation pump - is circulated through components arranged there, in particular through the at least one filter and the limescale protection device.

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