WO1997003025A1

WO1997003025A1 - House water decalcifying process

Info

Publication number: WO1997003025A1
Application number: PCT/EP1996/003022
Authority: WO
Inventors: Klaus Eckert; Georg Eckert
Original assignee: Grünbeck Wasseraufbereitung GmbH
Priority date: 1995-07-10
Filing date: 1996-07-10
Publication date: 1997-01-30
Also published as: EP0842124A1

Abstract

In a house water decalcifying process, a sufficient number of seed crystals is at first generated in the water to be decalcified, before the water is heated while flowing through a thermal section, and the carbonates generated in the thermal section are made to agglomerate into crystal aggregates around the seed crystals. The crystal aggregates are then removed by means of a filter or another separating system. The seed crystals are generated for example by a preliminary physical treatment or are added as lime particles if the water to be decalcified does not contain already a sufficient number of seed crystals. Also disclosed is a device for carrying out the process.

Description

Process for decalcifying domestic water and device for carrying out the process.

The invention relates to a method for decalcifying domestic water and a device for performing the method.

Chemical water treatment devices are probably the most known for decalcifying domestic water. Disadvantages of these devices are the periodic replenishment of the chemicals, frequent checks, calcium and magnesium deprivation, and an additional sodium load in the water.

Devices with a device for physical water treatment on a magnetic, electromagnetic or electrophysical basis are intended to prevent limescale deposits in the water supply system (scale). The water is passed through a magnetic or electromagnetic field, which causes the separation of the finest crystals, which are rinsed on, but are so fine that they cannot be separated with conventional water-dirt filters (passage width> 80 μm). The excreted calcium or magnesium carbonate particles remain in the water, which is therefore not noticeably descaled (KJ Kronenberg "Advantages of magical water treatment", SBZ 21/89, p. 1534; D. Frahne "What is physically verifiable", SBZ 11/1991, p. 30). In fact, the water hardness cannot be influenced, but the lime in the tap water is only converted into a form that does not accumulate on the pipeline walls with the formation of scale.

A method known from DE-A-25 26 674 is used for the treatment of industrial wastewater and mineral water to be processed thermally, and, since domestic water is not thermally processed, it is not intended for decalcifying domestic water. The water is first passed through a magnetic field and then heated to 80 ° C to 180 ° C. The failing Some of the substances are deposited in the heating device, and in some cases they are separated from the water in a settling tank. The deposits on the inner surface of the heating device are conveyed mechanically into the settling tank by means of a stripping device.

US-A-5 149 438 describes a closed-circuit water to be softened process intended for the treatment of hard water in boilers and the like. The cycle of water is essential in this process. In this way, large crystals with an amorphous character are obtained in a colloidal suspension in the water cycle. In this method, the water to be softened flows through a filter arranged upstream of the magnetic device, through which particles which have arisen in a previous cycle are filtered out.

A service water heater of a domestic water supply is known from an assembly and operating instruction "Sanicube" from Rotex, DE, "Installation and Connection or Warm Water Connection", pp. 4 and 5, which includes a heat exchanger with a PE Contains X-tube. The assembly and operating instructions contain a reference to the apparently occasional and undesirable phenomenon of limescale deposits in the system, which can lead to clogging of the tapping points and to malfunctions and are therefore appropriately retained in a filter to prevent damage .

Further prior art as a technological background is contained in DE-A-39 32 565, EP-AO 493 313, US-A-4 731 186, EP-AO 338 697 and the following references: LIMTERT, GJC RABER, JL: Tests of nonchemical scale control devices in a conse-through system. In: Materials Performance 24, 1985, H. 10, pp. 40-45; MAIER Dietrich, ULMER Jürgen: Investigations on the influence of the test conditions on the effect of physical water treatment devices in the test case. In: what- ser, Abwasser, 132, 1991, No. 1, pp. 16-19; CHEREMISINOFF, Nicholas P., CHEREMISINOFF, Paul N.: Tiltration Equipment for Wastewater Treatment, Prentice Hall, Englewood Cliffs, 1993, pp. 35-38; HAHN, Hermann H.: Wassertechnololgie, Springer-Verlag, Berlin, 1987, pp. 169-173.

The invention has for its object to provide a method of the type mentioned and an apparatus for performing the method, in which the monitoring and refilling of any consumer materials is no longer necessary, and in which the water is actually decalcified by Lime can be extracted from the water cycle and the hardness of the water can thus also be influenced, the aforementioned health risks being avoided, ie in which house water can be effectively decalcified without the use of chemicals and with structurally simple means.

In the process according to claim 1, readily soluble bicarbonate is continuously converted to sparingly soluble carbonate and the carbonates are brought together in the thermal section to form crystal aggregates on the crystallization nuclei. The crystal aggregates are then separated by filters or another separation system. In the case of certain types of water with a sufficient content of crystal nuclei, no additional measures are necessary to provide the sufficient number of crystal nuclei. In accordance with the process, the residence time, the temperature and, if appropriate, the volume flow of the water in the thermal section are selected so that the crystal aggregates are produced with a certain size, and since the surface roughness and the material selection of the inner wall of the thermal section prevent the crystal aggregates from adhering the actually disadvantageous precipitation of the lime is used profitably for permanent decalcification of the house water. Descaling is a desirable reduction in the hardness of the Domestic water and heated, decalcified service water can be removed.

Due to the selection of the process parameters, larger crystals or crystal aggregates are generated, which can already be filtered out with commercially available dirt filters. The advantage achieved is that the lime originally contained in the water can actually be removed from the system by means of conventional filtration or separation and the hardness of the water can thus be influenced in a targeted manner. In addition, deposits in the pipelines are essentially avoided, without having to carry out regeneration processes. Compared to the chemical processes, the process can be designed to be absolutely maintenance-free and can be carried out without the use of salts. The health burden, for example due to an increased sodium content, is avoided, the elimination of additional rinsing processes reduces the environmental impact and avoids consequential costs. The process is fully effective even at temperatures above 60 ° C.

In a preferred form of the process, the crystallization nuclei are provided in the form of lime particles, for example lime sand. These lime particles can be provided permanently during operation. However, it is also conceivable to use the lime particles to accelerate the start-up phase of the process until a stable decalcifying effect occurs, which may continue to run without the further addition of lime particles. It has proven to be expedient to use the lime particles with an average grain size of preferably approximately 20 μm to 200 μm. Lime particles with these sizes lead to a good process result and are easy and inexpensive to provide, for example in the form of lime sand. The lime particles can be supplied before or in an inlet section of the thermal section or also within the thermal section because they cause the crystal aggregates to form within the thermal section. There- In accordance with a further process example, it may be expedient to heat the lime particles defining the crystallization nuclei to approximately the temperature prevailing in the thermal stretch before they are added in order to accelerate the formation of the carbonate crystal aggregates or to avoid a delaying shock effect .

Alternatively or additively, the desired result can be improved by first passing the water to be decalcified through a magnetic or electromagnetic field in order to allow the formation of very fine crystals as crystallization nuclei, by means of which then larger and filterable in the thermal section Crystals or crystal aggregates are generated.

The crystallization nuclei provide a further, expedient process variant by recirculating part of the water already loaded with lime particles in the thermal zone into the inlet zone or the thermal zone. In this way, if necessary, the crystallization nuclei or the crystals formed on the basis of the crystallization nuclei are used repeatedly and, so to speak, the water to be decalcified is permanently enriched with crystallization materials or lime particles without external supply. Process-loaded water can be recirculated from upstream of the filter or the separating system, or water that has already passed the filter or the separating system and then gets rid of the large and filterable crystal aggregates, and small crystals or crystal germs contains that could pass through the filter or the separating system and be used again or even several times for decalcifying. A very large number of crystallization nuclei can thus be provided with little effort. According to the method, the parameters, residence time and temperature of the water in the thermal section are expediently coordinated with one another and selected so that the carbonate crystal aggregates achieve an average size of at least 80 μm, which can be found in a conventional filter or can be separated particularly effectively in a structurally simple separation system.

In particular, it is advantageous according to the process to heat the water in the thermal section to a temperature of at least 40 ° C. However, the temperature can also be higher and reach 80 ° C or more. In an expedient form of the process, the residence time can be at least 2.5 minutes, preferably even about 30 minutes or more. Depending on the construction and the temperature, further deviations from these values are quite possible.

To separate the crystal aggregates, i.e. For decalcifying or reducing the water hardness, filtering and / or separating are suitable.

Decalcified hot water is produced with the aforementioned process variants. If, alternatively, cold decalcified water is required for certain applications, in a further process variant the heat supplied in the thermal section is removed from the treated water by a heat exchanger and returned to the thermal section in a circuit by means of a heat exchanger. This process variant is environmentally friendly and avoids any significant waste of thermal energy.

The device which can be used according to the invention to carry out the method offers structurally simple requirements for an effective, permanent decalcification of running house water and thus for reducing the water hardness, without the need to intervene periodically from the outside, Frequent maintenance and permanent monitoring of the function. The sufficient number of crystallization chambers, either already contained in the water to be decalcified or provided in the source, lead to the carbonate crystal aggregates loading the water due to the heating in the thermal section, which in principle already have a low tendency to adhere to the Have pipelines and are additionally brought to the filter or to the stripping system in that the inner wall of the thermal section is made of a material with low chemical affinity and such a low surface roughness that no carbonate crystal aggregates adhere. The structural concept of the device also makes it possible to set the dwell time and the volume flow in the device in such a way that a decalcifying effect adapted to the respective requirements is enforced without a boiler.

With appropriate properties of the water to be decalcified, i.e. with a water quality that already contains a sufficient number of tiny particles that can serve as crystallization nuclei in the thermal section, the source of the crystallization nuclei is the water connection itself. In many cases, however, it is advantageous, among other things, about the efficiency of the device to improve, as a source of the crystallization nuclei to use a device for physical water treatment on a magnetic, electromagnetic or electrophysical basis.

In a preferred embodiment, the thermal section is tubular with a length of at least 2 m. The upper limit is determined by economic factors and can be greater. The optimal length of the thermal path depends, among other things, on the selected dwell time, the tube diameter and the temperature of the water, and the need to form larger crystals or crystal aggregates on the crystallization nuclei, in technical terms Regarding the desired degree of descaling is an essential factor and economic factors play an upper limiting role.

The thermal section is preferably designed such that the water to be decalcified is heated to at least 40 ° C. The upper temperature limit in the thermal section is given by the boiling point of the water.

A preferred embodiment has at least one container with lime particles in the flow path and, if appropriate, a metering device, optionally with a time control. The lime particles can be in the form of lime sand in the container and are added to the water to be descaled as required. As a rule, the addition is carried out to accelerate the start-up phase of the process until the equilibrium state is reached with a stable process sequence. Whether lime particles continue to be added depends on the composition of the water to be decalcified and / or the desired reduction in hardness.

The container can expediently be heated in order to heat the lime particles, preferably to approximately the temperature prevailing in the thermal section. This measure ensures an undisturbed and rapid process sequence because the water to be decalcified does not need to heat the added lime particles and these are immediately ready for the carbonate crystal aggregates to adhere or form as soon as they reach the water to be decalcified.

In a particularly preferred embodiment, the filter used has a passage width between 5 and 500 μm, in particular between 25 and 200 μm, and particularly preferably a passage width between 80 μm and 110 μm. The filter used in each case depends on the desired degree of decalcification or the desired reduction in water hardness. The filter should be designed to be backwashed in order to be able to ensure constant decalcification with little construction effort.

A preferred embodiment has a filter with a drain for the separated lime, which can either be operated manually or automatically, in order to remove the separated lime from the device manually or automatically, depending on the occurrence.

A separation system proposed as an alternative or even additive to the filter can be a sediment separator or a suspended matter separator which works with gravity and has a settling zone for the flowing water. The separating system can also be provided with a manually or automatically operated drain in order to be able to remove the separated lime from the device.

In a practical embodiment, the thermal section is a pipeline in the manner of a pipe coil with a heating device, and the course of the thermal section can be chosen to be spiral, meandering or loop-shaped. The heating device should be designed electrically or as a heat exchanger, various primary energies being able to be used. Indirect heating of the pipe coil can also be advantageous.

In order to prevent the crystal aggregates from being deposited on the inner wall in the course of the thermal stretch, the pipe coil should be made of plastic with low chemical affinity and low surface roughness. The specified types of plastic are particularly suitable for this purpose. In an expedient embodiment, the roughness of the inner wall of the pipe coil should not exceed a value of 3 μm, in particular 1.5 μm.

An embodiment with a recirculation line for water loaded with lime particles or carbonate crystal aggregates, which has already passed the thermal section, is particularly expedient. The recirculation line leads from a connection upstream or downstream of the filter or the separating system to a connection upstream or in the thermal section. When the water is drawn off upstream of the filter or the separating system, some of the lime particles or carbonate crystal aggregates are passed through the thermal section again in order to produce even larger and easily separable carbonate crystal aggregates. If, on the other hand, the water is tapped downstream of the filter or the separating system, then smaller limescale particles or carbonate crystal aggregates that have not been separated are brought back into the thermal section in order to enrich the water to be decalcified.

In a further, expedient embodiment, a heat exchanger is provided as part of the heating device, which removes heat from the heated water downstream of the thermal section and returns the heat in the circuit to the thermal section. Cold decalcified water can be produced in this way. If the heat exchanger can be switched on, heated or cold decalcified water can be removed as required.

"Decalcified" water is to be understood as water from which part of the lime has been removed.

Embodiments of the subject matter of the invention are explained below with reference to the drawing. Show it:

1 is a schematic diagram of a first embodiment of a device according to the invention, 2 is a schematic diagram of a second embodiment,

2A shows a schematic diagram of a further embodiment, and also a detailed variant,

3 is a schematic diagram of a further embodiment,

4 shows a sketch similar to a block diagram, which in principle shows the device according to the invention with its components as part of a domestic water system, and

FIG. 5 shows a sketch similar to FIG. 4 of a further embodiment.

Although the invention is described below in principle or with reference to individual units as part of a domestic water system, a device is intended to serve as a compact unit for various applications, e.g. to protect devices in which lime has extremely disadvantageous effects, such as washing machines, dishwashers and the like, which can be arranged downstream of the device or equipped with the device. Furthermore, the method and the device intended to carry out the method are also suitable for industrial use, for example for softening boiler feed water or as a first stage for producing deionized water.

In the following description, the same or equivalent components are provided with the same reference numerals.

In the embodiment according to FIG. 1, the water to be descaled contains a sufficiently large number of crystallization nuclei to decalcify, if necessary, without additional generation of crystallization nuclei. In this respect is a source 29 of crystallization nuclei of symbolic importance. It can be directly the connection of the water to be decalcified, which enters the device 1 through an inlet 5. Downstream of the source 29 are a thermal section 3 and behind this a filter 4 or another separation system is provided. The decalcified water leaves the device through an outlet 6, a line 7 running from the inlet 5 to the outlet 6.

The water from the source 29 containing the sufficient number of crystallization nuclei is heated in the thermal section 3. Easily soluble bicarbonate is converted to poorly soluble carbonate, the carbonates being brought together to form carbonate crystal aggregates on the crystallization nuclei due to a predetermined residence time, the temperature in the thermal zone 3 and the flow rate of the water in the thermal zone 3. When leaving the thermal section 3, the carbonate crystal aggregates are of sufficient size to be separated by the filter 4 or the separating system. The water heated in the thermal section 3 flows in a warm water outlet line 25 into the filter 4.

In FIG. 2, in order to improve the efficiency and / or for types of water in which a sufficiently large number of crystallization nuclei cannot be assumed, the source 29 is a device 2 for physical water treatment on a magnetic, electromagnetic or electrophysical basis. The device 2 is connected via line 7 to the thermal section 3.

In the device 2, the separation of the finest calcium carbonate or magnesium carbonate, ie crystallization nuclei, is effected in a known manner, for example by at least one magnetic or electromagnetic field. In the thermal section, this is the separated crystals water containing onskeime heated to a temperature of at least 40 ° C, the actual optimal temperature depending on the dwell time, the flow length of the thermal section, the water hardness and the pipe diameter. In the ^' thermal range 3, calcium carbonate and / with a preselected residence time are used on the finest crystals which are used as crystallization nuclei and which originate from the device 2, owing to the increased temperature and the prevailing flow conditions ^' and or magnesium carbonate, so that particles with an average particle size ^ 80 μm are permanently produced. These larger crystals or crystal aggregates, which tend not to separate in the pipes, are permanently separated in the filter 4 or in the separating system, so that they are no longer contained in the outflowing water and the lime content is reduced.

In the thermal section with a tubular design, the length of a pipeline 15 should be at least 2 m, the actual optimal length depending on the dwell time, the pipe diameter and the desired temperature of the water.

Passages between the minimum of 5 μm and the maximum of approximately 500 μm are possible for the filter 4. The appropriate passage width depends on the desired degree of decalcification and other system limits. Within these limits, a passage width between approximately 80 μm and 110 μm has proven to be practical, as is the case with commercially available filters.

In the embodiment according to FIG. 2A, a container 29 'is provided as the source 29 for crystallization nuclei which contains lime particles, for example in the form of lime sand, which are added to the water to be decalcified, specifically in the continuous line 7 in an inlet section to the thermal section 3 or within the thermal section 3. The lime particles can be added, for example, during a running-in phase of the process in order to accelerate the running-in phase until a stable process equilibrium is reached. However, it is also conceivable to add lime particles permanently in order to maintain the sufficient number of crystallization nuclei in the water to be descaled. A metering device D for adding the lime particles can be provided, possibly in conjunction with a time control Z for actuating the metering device. The container 29 'is expediently provided with a heating device H in order to heat the crystallization chamber, expediently to approximately the temperature prevailing in the thermal section 3. As an alternative, the container 29 'could also be arranged within the thermal section 3 (indicated by dashed lines) and is heated in the thermal section 3.

3 can be used to deliver decalcified cold water (permanently or as required). The warm water outlet line 25 of the thermal section 3 is assigned a heat exchanger 26 which is connected to the thermal section 3 by a heat exchanger circuit 27. The heat exchanger 26 forms e.g. a part of the heating device of the thermal section 3. The heat supplied to the water in the thermal section 3 is recirculated to the thermal section 3. The heat exchanger 26 is connected to the filter 4 via a cold water outlet line 28. The heat exchanger 26 (or the heat exchanger circuit 27) could be switched off if necessary in order to produce decalcified hot water in some cases.

4 shows the individual components of the device 1 according to the invention as part of a domestic water system. The water to be treated comes from a cold water house connection 8 and passes through a counter 9 and a first cold water filter 10 (passage width of approximately 100 μm) to the source 29. In a secondary loop 11 provided for maintenance reasons, the device 29 for the physical water treatment (or the container 29 '), for example, is arranged as the source 29 and leaves the water through the line 12 with the crystallization nuclei excreted therein. From a branch 13, the water either reaches the cold water consumers symbolized by the arrow 14, or through conventional valves and pumps (not explained in more detail) into the thermal section 3. The thermal section 3 is equipped with a heated pipe coil 15 of a water heating device 16 educated.

The water heating device 16 is constructed according to the continuous system and has flow and return connections 18 to a heat source, not shown, from which the medium 19 contained in a container 20 of the water heating device 16 is heated, which serves as a heating device for the thermal section 3 .

After the larger crystals or crystal aggregates have been formed in the thermal section 3 as a function of the above-mentioned variables or parameters (flow rate, residence time, temperature), the heated water passes through a line 21 into the filter 4, which for example has a passage width between 80 μm and 110 μm. The filter 4 is expediently designed to be backwashed and has a lime drain 22 which can be operated either manually or automatically. The decalcified hot water passes from the filter 4 via a line 24 to hot water consumers 23.

The pipe coil 15 forming the thermal section 3 is heated, for example, via a heat transfer medium. In alternative embodiments, the pipe coil can have an electrical direct heating or after the direct heat exchange heated principle, or indirectly via a secondary heat transfer medium.

Due to the minimum length of 2 m for the thermal section, it is in any case advantageous to design the thermal section as a pipeline in the manner of a pipe coil in a space-saving manner and d longer than 2 m.

Plastic materials with low chemical affinity and low surface roughness are preferably used for the thermal section 3 or the pipe coil 15. The roughness of the inner wall of the tube coil 15 or the thermal section 3 should not exceed a value of 3 μm, in particular 1.5 μm. Plastic materials are polyethylene, cross-linked polyethylene, polypropylene, polybutene, polyamide or polymeric fluorinated hydrocarbons, but also other materials with the aforementioned specifications or properties. The plastic material used in each case could also be provided in an inner coating of metal pipes.

In addition to providing a sufficient number of crystallization nuclei, it is important for the process to set the residence time, the temperature and the volume flow of the water in such a way that the crystal aggregates reach a size which is sufficient for filtration or for separation in alternative separation systems. The aforementioned values or ranges for the process parameters should only be understood as reference points for the person skilled in the art, who is able to determine the optimal combination of the parameters in each case.

FIG. 5 is a simplified illustration of another embodiment similar to FIG. 4. As, if necessary, additional source for providing a sufficient number of crystallization nuclei or crystals for depositing, for example the carbonates, here serves a recirculation device with a recirculation line 32, which returns part of the water that has already passed through the thermal section 3, for example by means of a pump 30 and a shut-off or throttle element 31. The recirculation line 32 can be connected to a connection 34 downstream of the thermal section 2 and upstream of the filter 4 in order to return water contaminated with crystals of all sizes. It is indicated by the broken line that the recirculation line 32 can also be connected to a connection 34 * downstream of the filter 4, in order alternatively to return decalcified water which is only loaded with small crystals or particles. The size of the crystals or particles then depends on the passage width of the filter 4. The recirculation line 32 can be connected upstream to a connection 33 of the line 7 in front of the thermal section 3. However, it is also conceivable to connect them to a connection 33 'in the inlet section of the thermal section or in the thermal section 3 itself or to a connection 33 "on the current provided device 2 or the source 29 or the container 29' The throughput of the returned water can be controlled or regulated. It is conceivable to completely shut off the recirculation line 32 as soon as a stable process equilibrium has been established.

All components of the device, e.g. 4 and 5, can be integrated in a partially or fully automated compact system.

In summary, in the method carried out with the device, a sufficient number of crystallization nuclei is initially provided or generated physically. Subsequently, the water is heated within the thermal section and lime contained in the water is separated on the crystallization nuclei until a certain particle size is reached which separates the larger crystals or crystal aggregates are subsequently made possible, the adhesion of the lime to the tube walls (scale) being suppressed by the selection of the material and the surfaces of the inner wall and their maximum roughness.

Claims

claims

1. Method for descaling domestic water, in which

a) a sufficient number of crystallization nuclei is provided in the water to be decalcified,

b) the water is then passed through a thermal section,

c) the flow rate, the dwell time and the temperature of the water in the thermal section are selected such that carbonate crystal aggregates of a size between 5 μm and 500 μm, in particular 25 μm and 200 μm, are formed,

d) the inner wall of the thermal section is made of a material with low chemical affinity and such a low surface roughness that the carbonate crystal aggregates do not adhere to it during the chosen dwell time, and

e) after the thermal stretch, the carbonate crystal aggregates are separated from the water.

2. The method according to claim 1, characterized in that the crystallization nuclei, preferably in the form of lime particles, e.g. as lime sand, and that, preferably, these crystallization nuclei are supplied to the water to be decalcified, at least during a process start-up phase.

3. The method according to claim 2, characterized in that the lime particles have an average grain size of 20 microns to 200 microns.

4. The method according to claim 2, characterized in that the

Lime particles are fed in front of or in an inlet section of the thermal section or within the thermal section.

5. The method according to claim 2, characterized in that the

Lime particles are preferably heated to approximately the temperature prevailing in the thermal range.

6. The method according to claim 1, characterized in that the

Crystallization nuclei are provided by passing the water to be decalcified through at least one magnetic or electromagnetic field.

7. The method according to claim 1, characterized in that the

Crystallization nuclei can be made available by recirculating part of the water in the thermal section with limestone particles into the inlet section or the thermal section in the water to be decalcified.

8. The method according to claim 1, characterized in that the residence time, the temperature and the flow rate of the water in the thermal range are chosen so that carbonate crystal aggregates of an average size> _80 microns arise.

9. The method according to any one of the preceding claims, characterized in that the water in the thermal section is heated to a temperature of at least 40 ° C.

10. The method according to any one of the preceding claims, characterized in that the residence time is chosen to be at least about 2.5 minutes, preferably about 30 minutes.

11. The method according to any one of the preceding claims, characterized in that the crystal aggregates formed are separated from the water loaded therewith by filtration and / or separation.

12. The method according to any one of the preceding claims, characterized in that for the production of decalcified cold water, the heat supplied in the thermal section is removed by a heat exchanger from the heated water and the circuit is again supplied to the thermal section by means of a heat exchanger.

13. An apparatus for performing the method according to any one of the preceding claims, characterized in that a source (29) of a sufficient number of Kristallisations¬ germs is provided in the water to be decalcified, that a thermal section (3) downstream of the source (29) Heating the water is connected so that the inner wall of the thermal section (3) is made of a material with low chemical affinity and such a low surface roughness that carbonate crystal aggregates which result in the thermal section and do not pollute the water to be decalcified are not formed adhere to the inner wall, and that a filter (4) or another separating system is provided downstream of the thermal section (3).

14. The apparatus according to claim 13, characterized in that the source (29) is designed as a device (2) for physical Was¬ water treatment on a magnetic, electromagnetic or electrophysical basis.

15. Device according to one of the preceding claims 13 and 14, characterized in that the thermal section (3) is designed such that the water therein can be heated to at least 40 ° C.

16. The apparatus according to claim 13, characterized in that a container (29 ') with lime particles, for example lime sand, is provided in the flow path into the thermal section (3) or in the thermal section (3), and that, preferably, a metering - Device (D) and optionally a time control (Z) for the metering device for supplying lime particles into the water to be decalcified is provided.

17. The apparatus according to claim 16, characterized in that the container (29 ') for heating the lime particles with a heating device (H) to approximately the temperature prevailing in the thermal section can be heated.

18. Device according to one of the preceding claims 13 to 17, characterized in that the filter (4) has a Durchlaß¬ width between 5 and 500 microns, preferably between 25 and 200 microns, and preferably between 80 and 110 microns.

19. The apparatus according to claim 18, characterized in that the filter (4) is designed to be backwashed.

20. Device according to one of the preceding claims 13 to 19, characterized in that the filter (4) has a drain (22) for the lime, which can preferably be operated manually or automatically.

21. The apparatus according to claim 13, characterized in that the separating system is designed as a sediment or suspended matter separator.

22. Device according to one of the preceding claims 13 to 21, characterized in that the thermal section (3) is designed as a spiral, meandering or loop-shaped tube coil (15) with a length of at least 2 m and with a heating device.

23. The device according to claim 22, characterized in that the heating device is formed electrically or as a heat exchanger.

24. The device according to claim 22, characterized in that the coil (15) is indirectly heated.

25. Device according to one of claims 22 and 24, characterized in that the pipe coil (15) consists of plastic material with low chemical affinity and low surface roughness, e.g. made of polyethylene, cross-linked polyethylene, polypropylene, polybutene, polyamide or from polymeric fluorinated hydrocarbons.

26. The apparatus according to claim 25, characterized in that the roughness of the inner wall of the coil (15) does not exceed a value of 3 microns, in particular 1.5 microns.

27. Device according to one of the preceding claims, characterized in that at least one, preferably a pump (30) and a shut-off device (31) containing recirculation line (32) loaded with lime particles or carbonate crystal aggregates, the thermal section (3) already passed water is provided which flows from or to a connection (34, 34 ') upstream or downstream of the filter (4) or the separating system to a connection (33, 33', 33 ") the thermal route runs.

28. Device according to one of the preceding claims, da¬ characterized in that as part of the heating device from a heated in the thermal section flowable, preferably switchable, heat exchanger (26) is provided, with which the heated water heat can be extracted, and that Heat exchanger (26) with the thermal section (3) is switched or switchable in a heat transfer circuit.