WATER HOT APPLIANCE

Description

[0001] The present invention relates to a water heater and a method for operating a water heater. A water heater is, in particular, a hot water storage tank, but is not limited thereto. The present invention is particularly applicable in all areas where corrosion protection is required.

[0002] It is known, particularly in the field of hot water storage tanks, to provide various types of corrosion protection systems. The often enameled storage tanks used in such devices have defects that, without appropriate passivation, develop into corrosion spots. Sacrificial anodes and impressed current anodes are particularly noteworthy examples of corrosion protection systems. The advantage of sacrificial anodes is that corrosion protection is maintained even without a power supply, and the power consumption of the hot water device is reduced. Sacrificial anodes, which often contain magnesium, are consumed through use and must be replaced from time to time. Determining when the sacrificial anode is consumed is complicated.

[0003] US Pat. No. 8,649,671 discloses an impressed current anode coated with magnesium. The initially present magnesium ensures passivation of the defects, and long-term corrosion protection is ensured by the externally supplied electric current.

[0004] Hot water storage tanks with a sacrificial anode and an impressed current anode are known from DE 101 126 60 and the utility model DE 20 2004 017 83. The described devices feature switching devices to switch from the impressed current anode to the sacrificial anode in the event of a power failure, thus ensuring continuous corrosion protection.

[0005] A device for monitoring a sacrificial anode is known from DE 10 2004 004 064. The condition of the sacrificial anode is determined by the protective current.

[0006] WO 2007 / 010 335 discloses a hot water device with an impressed current anode and a magnesium anode used in combination.

[0007] In view of the state of the art, one task was to provide an improved hot water device that ensures reliable corrosion protection with reduced power consumption.

[0008] According to a first aspect, the object is achieved by a hot water device, in particular a hot water storage tank, according to claim 1.

[0009] Insulated mounting of the impressed current anode or sacrificial anode in the storage tank means there is no direct electrical contact between the respective anode and the metal container casing. Insulation is applied between the container and the respective anode.

[0010] The invention is based on the finding that the electrical potential between the impressed current anode and the storage device indicates the state of consumption of the sacrificial anode. The electrical potential, and thus the protective potential of the storage device, depends on the state of consumption of the sacrificial anode. This design therefore enables actual detection of the anode state.

[0011] The hot water device has an electrical control system which is designed to selectively supply the impressed current anode with current, wherein the potential determination unit is preferably formed as part of the electrical control system.

[0012] The sacrificial anode is connected electrically or de-energized to the storage device via the electronics of the electrical control system by means of a switchable contact.

[0013] The hot water device further comprises a wear detection unit which is configured to detect wear of the sacrificial anode and to apply an electrical potential to the impressed current anode when wear of the sacrificial anode is detected.

[0014] Because the corrosion protection device according to the invention has a wear detection unit, the impressed current anode is only subjected to an electrical potential when wear of the sacrificial anode is detected, thus eliminating power consumption whenever the sacrificial anode is not worn. A particularly significant reduction in power consumption is achievable, particularly when wear detection occurs without current. In contrast to the prior art, in which the sacrificial anode is provided as a safety solution in the event that the impressed current anode fails, for example, in the event of a power outage, the impressed current anode is provided here as an emergency solution in the event of failure, i.e., the consumption, of the sacrificial anode.

[0015] In one embodiment, the wear detection unit comprises a pressure switch configured to trigger upon wear of the sacrificial anode.

[0016] The pressure switch has the particular advantage that a contact, which, for example, applies electrical potential to the impressed current anode, is only closed when a mechanical effect, namely pressure, is exerted on the wear detection unit. All pressure switch designs known to those skilled in the art are suitable for this application.

[0017] In one embodiment, the pressure switch is arranged such that an internal pressure of the accumulator is applied to the pressure switch when the sacrificial anode wears out, which is suitable for triggering the pressure switch.

[0018] In one embodiment, the sacrificial anode has a cavity in the interior which, in an unused state, is insulated from the container volume, wherein the pressure switch is in fluid communication with the cavity such that a breakthrough through the impressed current anode into the cavity triggers the pressure switch.

[0019] As soon as the sacrificial anode is sufficiently consumed and the water flows from the inside of the storage tank into the cavity inside the sacrificial anode, the internal pressure of the tank is applied to the pressure switch. This triggers the pressure switch. The pressure switch is therefore designed in such a way that the internal pressure in the storage tank of the hot water device is sufficient to trigger it.

[0020] In one embodiment, triggering the pressure switch closes the impressed current anode circuit.

[0021] By closing the impressed current anode's circuit directly upon triggering the pressure switch, a particularly simple supply of the impressed current anode with the protective current is possible. In particular, a mechanical coupling can directly lead to the mechanical movement or triggering of the pressure switch closing the circuit.

[0022] In one embodiment, the hot water device has an electrical control, wherein the triggering of the pressure switch provides a signal to the electrical control and the electrical control is configured to supply the impressed current anode with current upon receipt of the signal from the pressure switch.

[0023] By triggering the pressure switch, which sends a signal to an electrical control system indicating that the sacrificial anode is depleted, an adapted response to the depletion of the sacrificial anode is possible. For example, as an alternative or in addition to immediately supplying the impressed current anode with power, the electrical control system can output a signal via an operating unit. This signal can then inform the user that the sacrificial anode is depleted and needs to be replaced. Alternatively or additionally, a delay can be built into the application of power to the impressed current anode. It is common practice for the pressure switch to trigger before the sacrificial anode is completely depleted. After the pressure switch has been triggered, the electrical control system can therefore wait for some time until the impressed current anode is supplied with power.During this transition period, a consumption signal can also be issued to a user at the same time.

[0024] In one embodiment, the sacrificial anode is mounted in an insulated manner within the storage device and is electrically connected to the storage device via the electronics of the electrical control system by means of a switchable contact, in particular is connected to the storage device in a currentless manner.

[0025] The switchable contact for connecting the sacrificial anode to the storage device can be designed, in particular, as a field-effect transistor or a relay. The preferred currentless connection between the sacrificial anode and the storage device ensures that no electrical current is required to ensure corrosion protection during the operating period in which the sacrificial anode is not consumed.

[0026] In one embodiment, the electrical control is configured to disconnect the electrical connection between the sacrificial anode and the storage device upon receipt of the signal from the pressure switch.

[0027] Separating the sacrificial anode and the reservoir upon receipt of the pressure switch signal is advantageous for the operation of the impressed current anode, since the sacrificial anode, when connected to the reservoir, acts as an external cathode for the impressed current anode and thus increases electrical power consumption while ensuring corrosion protection with the impressed current anode. In this embodiment, the electrical power consumption is reduced while ensuring corrosion protection with the impressed current anode.

[0028] In one embodiment, the hot water device further comprises a display unit, wherein the electrical control is configured to output a consumption state of the sacrificial anode to the display unit based on the signal of the pressure switch.

[0029] For example, the display can show that the sacrificial anode is not used up until the pressure switch is triggered. When triggered, it can then be indicated that the sacrificial anode is used up. Preferably, it is also indicated that a certain time has passed since the pressure switch was triggered. For example, a display can switch to yellow when triggered and finally switch to red after a certain time, with red being understood as an indication that the sacrificial anode indeed needs to be replaced urgently. Of course, these are only examples of how the wear status of the sacrificial anode can be shown on the display unit; other designs are also conceivable.

[0030] In one embodiment, the hot water device further comprises a heating flange which is designed to heat the interior of the storage tank, wherein the sacrificial anode is introduced into the heating flange and can be conductively connected to the container or can be mounted directly in the storage tank.

[0031] In one embodiment, the corrosion protection device comprises a DC voltage source for supplying the impressed current anode with DC current, wherein the DC voltage source is a constant or a regulated DC voltage source.

[0032] Particularly advantageously, in this embodiment, the electrical potential between the impressed current anode and the storage device can indicate the state of consumption of the sacrificial anode. This embodiment is based on the realization that the electrical potential, and thus the protective potential of the storage device, depends on the state of consumption of the sacrificial anode. This design therefore enables actual detection of the anode state.

[0033] In one embodiment, the sacrificial anode is electrically connected to the storage device by means of a switchable contact, wherein the potential determination unit is configured to determine the potential between the external current anode and the storage device cyclically, in particular at regular intervals.

[0034] Because the potential is determined cyclically, it is possible to make a statement about the consumption status of the sacrificial anode at cyclic intervals.

[0035] In one embodiment, the potential determination unit is configured to open the contact between the sacrificial anode and the storage device for a potential determination between the impressed current anode and the storage device.

[0036] By opening the contact between the sacrificial anode and the storage tank, sources of error when determining the potential between the impressed current anode and the storage tank are minimized. In particular, this enables IR-free measurement. The brief separation of the electrical connection between the sacrificial anode and the storage tank is not critical for corrosion protection. After the potential determination has been performed, the electrical contact is preferably closed again to ensure continued corrosion protection.

[0037] In one embodiment, the hot water device has an operating unit, in particular with a display device, and / or an interface, in particular a wireless interface such as WLAN, wherein the wear detection unit is configured to output a signal describing the wear of the sacrificial anode to the operating unit and / or the interface.

[0038] Using the display device and / or the interface, the hot water device can communicate the status, in particular of the sacrificial anode. This embodiment, which includes the display device and / or the interface, can be combined with all of the embodiments described above. In particular, the display device and / or the interface can be combined with detection by means of a pressure switch and / or with potential measurement.

[0039] According to a further aspect, a method for controlling corrosion protection of a hot water device, in particular a hot water storage tank, is proposed.

[0040] The hot water tank comprises a tank and a corrosion protection device with a sacrificial anode and an impressed current anode. The method comprises the following steps: determining a potential between the impressed current anode and the tank; disconnecting an electrical connection between the sacrificial anode while the potential between the impressed current anode and the tank is being determined; and determining wear of the sacrificial anode based on the potential determined between the impressed current anode and the tank, and optionally, upon determining that the wear exceeds a predetermined threshold: communicating the wear to a control panel and / or an interface of the hot water device; and / or applying a DC voltage supply to the impressed current anode, preferably a DC voltage supply that can be regulated depending on the determined wear; and / or closing the electrical connection of the sacrificial anode to the tank.

[0041] Further advantages and preferred embodiments are described below with reference to the attached figures. Herein: Fig. 1 schematically and exemplarily shows a non-claimed hot water device, Fig. 2 schematically and exemplarily shows a further embodiment of a non-claimed hot water device, Fig. 3 schematically and exemplarily shows an embodiment of a hot water device and Fig. 4 schematically and exemplarily shows a flow diagram of a non-claimed method for controlling corrosion protection of a hot water device

[0042] Fig. 1 shows schematically and by way of example a non-claimed hot water appliance 1 designed as a hot water storage tank. The hot water appliance 1 comprises a storage tank 10, which has a container volume 12 inside, in which, in particular, water to be heated, preferably domestic water, is kept ready. The liquid in the storage tank 10, in particular water, is heated via a radiator 14. The radiator 14 is mounted in the base of the storage tank 10 via a heating flange 16 in the example. Inlets and outlets of the storage tank 10, as well as electrical connections of the radiator 14, are omitted from the drawing for the sake of simplicity. Hot water appliances 1, such as the hot water storage tank shown as an example, are generally known in the art.

[0043] The hot water device 1 differs from known hot water devices in the design of its corrosion protection. For this purpose, a corrosion protection device 20 is provided, which comprises an impressed current anode 22 and a sacrificial anode 24. The sacrificial anode 24 and the impressed current anode 22 can be positioned arbitrarily within the storage tank 10. The arrangement shown as an example within the heating flange 16 is one possibility; alternatively, the respective anodes can of course also be mounted directly into the storage tank 10.

[0044] The corrosion protection device 20 has a wear detection unit 30 configured to detect wear of the sacrificial anode 24. A channel 26 is formed inside the sacrificial anode 24 for this purpose and is in fluid communication with a pressure switch 32. As an alternative to a pressure switch 32, this element can also be configured as a pressure sensor. The material of the sacrificial anode 24 is gradually consumed by inherent corrosion and the reactions required for cathodic corrosion protection. Once the material degradation has progressed sufficiently, water from the container volume 12 penetrates the channel 26, whereby the water pressure is applied to the pressure switch 32 and actuates it. For this purpose, the pressure switch can, for example, have a sensor unit.This pressure of the water flowing into channel 26 activates an electrical contact 33 and electrically connects the impressed current anode 22, for example, to a DC voltage source in an electronic system 40. The DC voltage source can be a constant or a regulated voltage source.

[0045] The impressed current anode 22 is installed in the hot water device 1 in an insulated manner. In this example, the sacrificial anode 24 is also installed in the storage tank 10 in an insulated manner with insulation 28. An electrical connection 29 ensures the closure of the circuit between the sacrificial anode 24 and the wall of the storage tank 10. Alternatively, the sacrificial anode 24 can also be in direct electrical contact with the tank wall.

[0046] A control unit 50 is connected to the electronics 40. A consumption status of the sacrificial anode 24 can be communicated via the control unit 50. Alternatively, an interface, for example, a wireless interface such as WLAN, etc., can also be provided in the electronics 40, so that a consumption status of the sacrificial anode 24 is transmitted to a user via the interface.

[0047] Fig. 2 shows schematically and exemplarily a further unclaimed embodiment of the hot water device 1. Fig. 2 differs from Fig. 1 In the embodiment of the wear detection unit 30, in particular, the pressure switch 32 is designed not to directly close the circuit of the impressed current anode 22, but rather to provide a signal to the electronics 40 via the closing of a contact 36. The electrical contact of the pressure switch 32 is then further processed in the electronics 40. This provides advantages in the fault detection of the corrosion protection device 20 as well as in the display options, in particular via the control unit 50. In this exemplary embodiment, the power supply of the impressed current anode 22 is then activated or switched by the electronics 40 depending on the signal from the pressure switch 32.

[0048] Furthermore, in Fig. 2 It can be seen that the sacrificial anode 24 is installed in an insulated manner and is electrically connected to the storage device 10 via the electronics 40 and a contact 38. Accordingly, an electrical contact is located on the electronics 40, which connects the sacrificial anode 24 to the container of the storage device 10. This contact is preferably closed when de-energized, in particular by means of a relay or a field-effect transistor. When the sacrificial anode 24 is used up, i.e. when the pressure switch 32 is triggered, the sacrificial anode 24 can be separated from the storage device 10 by means of the electronics 40. This is advantageous for the operation of the impressed current anode 22, since the sacrificial anode 24, when connected to the storage device 10, represents an external cathode for the impressed current anode 22.

[0049] Fig. 3 shows a schematic and exemplary embodiment of another embodiment of the hot water device 1. Instead of the pressure switch 32, the wear detection unit 30 detects wear in this example by means of a potential measurement. In this example, the impressed current anode 22 and the sacrificial anode 24 are each shown mounted by means of insulation 28 and separately from the heating flange 16. Of course, a combination of one or both of the anodes in the heating flange 16 is also conceivable.

[0050] In this example, the impressed current anode 22 and the sacrificial anode 24 are connected to the storage device 10 via the electronics 40. The wear detection unit 30 comprises, within the electronics 40, a potential determination unit 42 configured to detect the protective potential in the container, as well as a preferably regulated DC voltage source 44 configured to impress the protective potential. The protective potential is understood in particular as the potential between the impressed current anode 22 and the container wall of the storage device 10. The protective potential builds up in particular near the container wall in the storage device, and preferably the potential is approximately used between the impressed current anode and the container wall.

[0051] The protective potential in the container is cyclically measured via the potential determination unit 42. This measurement occurs even when corrosion protection is ensured by the sacrificial anode 24. During the potential measurement, a switch 46 is opened so that no voltage impressed by the voltage source 44 is present. For an IR-free measurement, the electrical connection between the sacrificial anode 24 and the storage device 10 is briefly disconnected by a switch 48.

[0052] Based on the detected protective potential, the consumption status of the sacrificial anode 24 can be determined during operation. As in the other versions, the consumption status can be displayed to the user via the control unit 50 or an interface, e.g., WLAN, etc., and / or used for control purposes. In this version, it is possible to detect the actual anode status.

[0053] In the design of the hot water device 1 according to Fig. 3 Corrosion protection can be ensured either by the sacrificial anode 24 or by the impressed current anode 22, whereby preferably only one of the two corrosion protection variants is active at any one time. If corrosion protection is ensured via the impressed current anode 22, the electrical connection between the insulated sacrificial anode 24 and the storage device 10 is interrupted by switch 48. Accordingly, the electrical connection between the DC voltage source 44 and the impressed current anode 22 is interrupted by switch 46 when corrosion protection is ensured via the sacrificial anode 24.

[0054] Switch 48 is closed when de-energized, ensuring corrosion protection even in the event of a power failure. Field-effect transistors or relays are suitable for this purpose.

[0055] Several operating options are conceivable for the corrosion protection device 20 according to this embodiment. Namely, the sacrificial anode 24 can provide basic corrosion protection, with the impressed current anode 22 becoming active and taking over corrosion protection when the sacrificial anode 24 is consumed and can no longer ensure corrosion protection. It is also conceivable that the impressed current anode 22 provides basic corrosion protection, while the sacrificial anode 24 only provides corrosion protection in the de-energized state.

[0056] Fig. 4 shows a schematic and exemplary flowchart of a method 200 for controlling corrosion protection of a hot water appliance. The hot water appliance can, in particular, be one of the hot water appliances 1 described with reference to the above explanations.

[0057] The method 200 comprises a step 210 of disconnecting the electrical connection between sacrificial anode 24 and storage device 10, followed by a step 220 of determining a potential between impressed current anode 22 and storage device 10. Alternatively, the potential determination can, of course, also be performed continuously or at regular intervals, in addition to the case in which the electrical connection was disconnected according to step 210.

[0058] In a step 230, wear of the sacrificial anode 24 is determined based on the potential between the impressed current anode 22 and the storage device 10 determined in step 210. For example, the potential can be compared to a threshold value. Optionally, it can be determined that the wear exceeds the predetermined threshold value.

[0059] In a step 232, the wear determined in step 230 is communicated to a control panel 50 and / or an interface of the hot water device 1. Alternatively or additionally, in a step 234, a DC voltage supply is applied to the impressed current anode 22 to ensure corrosion protection by means of the impressed current anode 22. Alternatively or additionally, in a step 236, an electrical connection between the sacrificial anode 24 and the storage tank 10 is closed by closing, for example, the switch 48. This ensures corrosion protection by the sacrificial anode 24.

Claims

1. A hot water appliance (1), in particular a hot water storage tank, comprising a storage tank (10) and a corrosion protection device (20) for protecting the storage tank from corrosion, wherein the corrosion protection device (20) includes a sacrificial anode (24) and an impressed current anode (22), which can each be reversibly mounted within the storage tank (10) and are insulated against the storage tank (10), wherein the corrosion protection device (20) includes a potential determining unit (42) arranged to determine a potential between the impressed current anode (22) and the storage tank (10), and a wear detection unit (30), wherein the wear detection unit (30) is arranged to determine wear of the sacrificial anode (24) based on the potential determined by the potential determining unit (42), wherein the hot water appliance (1) includes an electric controller (40) arranged to selectively supply the impressed current anode (22) with power, wherein the sacrificial anode (24) is electrically connected to the storage tank (10) via the electronics of the electric controller (40) by means of a switchable contact (38), characterised in that the switchable contact (38) contains a field effect transistor or a relay and is closed in the currentless state, so that the sacrificial anode (24) is connected to the storage tank (10) via the switchable contact (38) when currentless.

2. The hot water appliance (1) according to claim 1, wherein the potential determining unit (42) is configured as part of the electric controller (40).

3. The hot water appliance (1) according to any one of claims 1 to 2, wherein the hot water appliance (1) further includes a display unit, wherein the electric controller is arranged to output a consumption state of the sacrificial anode (24) based on the signal of the potential determining unit (42) to the display unit.

4. The hot water appliance (1) according to any one of the preceding claims, wherein the hot water appliance (1) further includes a flanged immersion heater arranged to heat the interior of the storage tank, wherein the sacrificial anode (24) is introduced into the flanged immersion heater and can be conductively connected to the tank, or can be directly assembled into the storage tank (10).

5. The hot water appliance (1) according to any one of the preceding claims, wherein the corrosion protection device (20) includes a DC voltage source (44) for supplying the impressed current anode (22) with DC current, wherein the DC voltage source (44) is a constant or a controlled DC voltage source (44).

6. The hot water appliance (1) according to any one of the preceding claims, wherein the potential determining unit (42) is arranged to determine the potential between the impressed current anode (22) and the storage tank (10) cyclically, in particular in regular intervals.

7. The hot water appliance (1) according to any one of the preceding claims, wherein the potential determining unit (42) is arranged to open the contact (38) between the sacrificial anode (24) and the storage tank (10) for determining the potential between the impressed current anode (22) and the storage tank (10).

8. The hot water appliance (1) according to any one of the preceding claims, wherein the hot water appliance (1) includes a programming unit (50), in particular comprising a display unit, and / or an interface, in particular a wireless interface such as WLAN, wherein the potential determining unit (42) is arranged to output a signal describing the wear of the sacrificial anode (24) to the programming unit (50) and / or the interface.