DE102008013943A1 - Hot water tank, has anode isolated to enamelled container, where change of anode current is determined based on comparison of anode current with absolute upper threshold value, absolute lower threshold value and/or relative threshold value - Google Patents

Abstract

The tank has an anode (2) isolated to an enamelled container (3), and a measuring value detecting and evaluation unit for detect and store an initial value of the anode current during initial operation of the hot water tank. The measuring value detecting and evaluation unit compares the detected anode current with an absolute upper threshold value, an absolute lower threshold value and/or a relative threshold value. A change of the detected anode current is determined over the time based on the comparison.

Description

The The present invention relates to a hot water storage and a Test device for testing an anode in a hot water tank.

at Hot water storage with a steel enamelled store is typically an anode used as corrosion protection. Thus, for example Defects in enameling are protected.

DE 10 2004 004 064 A1 shows a device for monitoring the consumption of an anode in a hot water storage tank. The anode is connected via an electrical line to a circuit device and the circuit device is connected via a further line to the wall of the hot water storage tank. A voltage is applied between the two electrical lines. The circuit device detects the current of the voltage source and compares this value with a limit value. If the limit value is undershot, a signal indicating the wear of the anode is output. Thus, a measurement of the anode current and the protection current, which is used as an indicator of the state of the anode.

It is thus an object of the present invention, a hot water tank to provide, which improved test possibility of used anode.

These The object is achieved by a hot water storage according to claim 1 solved.

The Invention thus relates to the idea of a hot water tank with an enamelled steel container, an insulated one Provide anode and a Meßwerterfassungs- and evaluation. in this connection the anode current is measured with the anode facing the memory is designed isolated. During the measuring process becomes the connection between the anode and the container interrupted. On the basis of the anode current can be conclusions in terms of enamel and water quality, in particular the conductivity of the water, as well as the size pull the inserted anode. When first commissioning the memory the anode current is measured and stored as initial value (s). The measured value acquisition and evaluation unit checks the consumption value of the anode. For this purpose, the measured value acquisition and evaluation unit determine the current anode protection current and Compare this value with a value that is included in the measured value acquisition and evaluation is stored. Alternatively, the determined Value compared with a calculated upper and lower threshold become. If the determined or measured value is the absolute or relative threshold exceeds, then can draw conclusions the wear of the anode and certain operating conditions of the memory.

Further Embodiments of the invention are the subject of the dependent claims.

embodiments and advantages of the invention will be described below with reference to FIGS Drawing explained in more detail.

1 shows a schematic representation of a hot water storage according to a first embodiment,

2 shows a partial sectional view of a storage container with an anode according to a second embodiment, and

3 FIG. 12 is a graph showing an anode current waveform over an operation time of a hot water storage according to the third embodiment. FIG.

1 shows a schematic representation of a hot water storage according to the first embodiment. The hot water tank has a container 3 with an anode 2 on, which by means of an insulating body 1 opposite the container 3 is isolated. The hot water tank also has a switch 5 as well as an ammeter 4 on, which with the anode 2 , the switch 5 and with the container 3 is coupled. Alternatively, in the pipe 6 a resistor or a diode may be coupled. The container 3 in turn is grounded PE. By means of the switch 5 can the anode with the container 3 be connected or from the container 3 be decoupled. In operation, the anode becomes 2 with the container 3 connected. However, if a measurement of the anode current by means of the current measuring device 4 should be performed, then the switch 5 operated and the connection between the anode 2 and the container 3 will be interrupted. Now, the anode current can be determined according to the first embodiment.

2 shows a partial sectional view of a container of a hot water storage according to a second embodiment. In 2 is in particular the cutout of the container 3 shown where the anode is installed. As already described in the first embodiment, the anode becomes 2 by means of an insulating body 1 from the container 3 isolated.

3 shows a graph of the anode current waveform over the operating time according to a third embodiment. In 3 is an absolute threshold AOS, an absolute lower threshold OFF and a relative threshold RS and the Ver Run the anode current shown. The anode current depends on the quality of the enamel, the water quality and the size of the anode used.

A Meßwerterfassungs- and evaluation, which the switch 5 , the electricity meter 4 and the resistor may further include a memory for storing anode current values. For example, the anode current can be measured during an initial startup of the memory and stored in the memory. Furthermore, the enamel quality and the water quality can also be saved. The measured value detection and evaluation unit detects the anode protection current and compares this value with values stored in the memory.

alternative or in addition to this, the determined anode protection current values with a calculated or calculated upper absolute threshold AOS and / or a lower absolute threshold OFF become. When the detected anode protection current is upper or lower Threshold falls below, then can be determined by this Underflows or overshoots to certain operating conditions Close the memory.

For example a drying cycle of the storage tank can be detected. During the drying cycle It may happen that there is no water in the tank is available. Thus, the radiator of the glows Memory on. Since there is no water in the reservoir, can also no anode current flow. The absence of the anode current is detected by the measured value acquisition and evaluation unit and a corresponding warning signal can be output.

Further a passivated anode can be detected. An oxide layer can due to self-corrosion over time on the anode form, so that the anode function goes out. The measured value acquisition and evaluation can detect this condition, in particular the course of the anode current is measured over time and a corresponding decrease of the anode current can be detected. If such a condition is reached, then the measured value and evaluation output a corresponding warning signal.

Of Furthermore, a short circuit can be detected. Such a short circuit can be done when the anode is no longer to the container is isolated. The measured value acquisition and evaluation unit can this Also detect condition and if necessary issue an alarm signal.

When passing an upper threshold, for example, because the anode current is too high, this can also be done by the data acquisition and Evaluation unit to be determined and a corresponding warning signal can be issued. An excessively high anode current can be, for example then occur when the conductivity of the water is too high or if there are too many defects in the mail of the container available.

If one of the states described above occurs, then the measured value acquisition and evaluation unit recognize the error, arrange (for example, by comparison with stored thresholds) and can issue a fault message.

If the anode current has a relative or absolute lower threshold falls below, then this can be a clue that the Anode needs to be changed. Here, however, in particular the taken into account the time course of the anode current to determine if the anode is used up. As a threshold to determine whether an anode change is needed, can be an absolutely fixed Threshold or a relative threshold relative to the relative Decay of the anode current to the output current signal can be determined.

The Measured value acquisition and evaluation unit can measure the anode current in Check automatically at regular intervals. If the absolute or relative threshold is undershot, This undershoot can be displayed.

To A change of the anode can be recalibrated be, in turn, the anode current is measured.

Of the Hot water storage described above can both a container have under pressure and a non-pressurized storage.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• DE 102004004064 A1 [0003]

Claims (4)

Hot water storage, with an enameled container ( 3 ), an insulated to the container anode ( 2 ), and a Meßwerterfassungs- and evaluation unit for detecting an anode current and for comparing the detected anode current values with at least one threshold value, wherein based on the comparison, a change of the detected anode current over time is detected. Hot water storage according to claim 1, wherein different Email qualities and the water conductivity through the measured value acquisition and evaluation unit is taken into account and saved accordingly. Hot water storage according to claim 1 or 2, wherein the measured value acquisition and evaluation unit is designed to initial start-up of the DHW cylinder an initial value of the anode current to capture and store. Hot water storage according to one of the claims 1 to 3, wherein the Meßwerterfassungs- and evaluation unit to is configured, the detected anode current with an absolute upper threshold (AOS), an absolute lower threshold (OFF) and / or a relative threshold (RS).