EP2931109B2 - Dishwasher for operation in various voltage systems - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION

The invention relates to a dishwasher designed for commercial use, in particular a (basket) pass-through dishwasher that can be operated in different low-voltage networks. The invention also relates to a method for saving energy in the standby mode of a dishwasher.

TECHNICAL BACKGROUND OF THE INVENTION

Dishwashers designed for commercial use, hereinafter referred to as commercial dishwashers, are characterized, without limiting the general public, by the fact that they are structurally designed for almost continuous operation, which places particularly high demands on pumps and high-performance electrical components such as relays and contactors, which cost millions of cycles should function without failure.

In addition, commercial dishwashers should clean the dishes as quickly and hygienically as possible while using as little water and energy as possible. A rinsing cycle (rinse cycle) of a commercial dishwasher usually only lasts a very short time (typically just a few minutes) and only requires small amounts of fresh water (typically only a few liters). The water used to rinse the items to be washed is heated electrically using radiators in a rinse water tank and in a dishwasher boiler. Tubular heaters are often used.

berechnet werden, wobei U die elektrische Netzspannung des Niederspannungsnetzes, an das die Spülmaschine angeschlossen ist und R den Widerstand des Rohrheizkörpers bezeichnet. Mit der Formel $I=\frac{U}{R}$

lässt sich der Strom I durch den Rohrheizkörper berechnen, der entsprechend abgesichert werden muss. Die vom Rohrheizkörper abgegebene Leistung ändert sich quadratisch und der Strom linear mit der Spannung, wenn der Widerstand des Heizkörpers konstant bleibt.Since the tubular heater can be considered in principle as a resistance R that converts electrical energy into heat, the power P of the tubular heater can simply be described as $\mathrm{P}=\frac{U^2}{\mathrm{R}}$

where U is the electrical mains voltage of the low-voltage network to which the dishwasher is connected and R is the resistance of the tubular heater. Using the formula $I=\frac{U}{R}$

the current I through the tubular heater can be calculated, which must be protected accordingly. The power delivered by the tubular heater changes quadratically and the current changes linearly with the voltage if the resistance of the heater remains constant.

The following exemplary table, which does not claim to be complete, makes it clear that there are many different mains voltages and fuses for on-site mains connections worldwide: <b>Table 1</b> country 3-phase alternating current external conductor voltage 1-phase alternating current voltage Typical protection Germany 400V 230V 16A, 25A, 32A Switzerland 400V 230V 10A, 16A Great Britain 415 B.C 240V 13A, 16A, 20A, 32A, 64A Industrial networks Europe 230V ./. 32A, 50A, 64A Australia 415 B.C 240V 15A, 20A, 32A Japan 200V 200V 20A, 30A Nets on ships 440 V ./. 20A Philippines 380 V 220V 16A, 32A

In addition, depending on the country, the low-voltage networks with three phases are designed as a delta network (three phases without neutral conductor) or star network (three phases with neutral conductor).

In order to ensure that the dishwasher can be operated on the respective low-voltage network and that optimal washing performance is achieved despite different network connections, different radiators and pumps adapted to the type of network, mains voltage and fuse are usually installed in the dishwashers, with several radiators often being installed in the dishwasher Dishwasher can be combined with each other. The different radiators and pumps in combination with different network types, network voltages and fuses lead to a changed structure of the entire power electrical circuitry.

This high variance in radiators and pumps and their combinations as well as the various power electrical circuits for the individual low-voltage networks results in a high variance in dishwashers. The storage of radiators and other power electronic components is extensive, the ordering and spare parts system for the machines is complicated and therefore prone to errors, and the maintenance of the dishwashers is correspondingly complex.

Commercial dishwashers usually use very little water per wash cycle, but they often have a high energy consumption - especially in standby mode. Without restricting the general public, it can be assumed that around 15 to 45 l of water are held in the wash water tank of a commercial rack-type dishwasher and 2.0 l to 5.0 l of fresh water are heated in the boiler per wash cycle. The tank water is circulated to clean the dishes. At the end of the wash cycle, the dishes are rinsed with hot fresh water from the boiler. The low water consumption is achieved by the fact that most of the tank water is used again and again to clean the dishes. The tank water is regenerated using the fresh water that is fed in from the boiler at the end of a wash cycle. Due to the very short rinsing times, the fresh water in the boiler must be heated from tap water temperature (approx. 5°C-25 °C) to approx. 80-85 °C in a very short time (e.g. less than 2 minutes). The water in the boiler is heated electrically via one or more heaters with an output of up to 12 kW. The rinsing water tank is heated in parallel to the boiler in order to keep the tank temperature of the dishwasher at approx. 62 °C. Significant amounts of energy are removed from the tank, particularly when washing cold dishes. In a pass-through dishwasher for commercial use, the output of the tank heater is typically up to 5 kW.

Conventionally, the water temperature in the boiler and in the flushing water tank is kept as constant as possible at the desired temperatures, which means that the radiators of the boiler and the flushing water tank are supplied with power even during times when no flushing cycle is active (standby mode), and accordingly increase the energy consumption of the dishwasher.

US 4,561,904 discloses a system and method for controlling a push-through dishwasher, which consists of a series of several work stations and washes, rinses, dries, etc. the items to be washed. A sensor at the entrance to the first work station detects the items to be washed on the conveyor belt of the dishwasher and the forward movement of the conveyor belt also monitored to guide the items to be washed through the dishwasher.

WO 2006/034760 A1 relates to the energy-saving operation of dishwashers and proposes a method and a device in which a group of electrical consumer elements of a dishwasher is assigned a maximum total electrical power. Furthermore, each electrical consumer element of this group is assigned at least two power levels. In a requirement determination step, an optimal combination of power levels is then selected depending on an operating state B of the dishwasher, whereby for each consumer element the selected power level is adapted to the power requirement of the consumer element in operating state B and whereby the total power of all consumer elements does not exceed the maximum total electrical power. Furthermore, the operation of the dishwasher can be divided into three phases, a start-up phase, a switch-on phase and a load control phase.

SUMMARY OF THE INVENTION

One object of the invention is to improve a dishwasher so that it can be operated in different low-voltage networks without any adjustment. A further object of the invention is to provide a dishwasher that can be operated in an energy-saving manner. It is also desirable that even when the dishwasher is operated in an energy-saving manner, the dishwasher can carry out a cleaning cycle in the shortest possible time and enables the items to be washed to be cleaned hygienically.

The invention discloses a (commercial) dishwasher according to claim 1, which automatically recognizes the on-site low-voltage network to which it is connected and, based on the recognized low-voltage network, optimally distributes the available power of the on-site low-voltage network (optionally taking a safety reserve into account) to individual electrical consumer elements of the dishwasher. For this purpose, a power controller is provided in the dishwasher, which controls the distribution of the power from the low-voltage network. The power controller comprises a switching unit, which connects the individual phases of the low-voltage network to the electrical consumer elements depending on the recognized low-voltage network. In addition, the consumer elements can be switched on and off dynamically, for example depending on the electrical consumer elements of the dishwasher required in the respective process step of the washing cycle.

In one embodiment of the invention, the (commercial) dishwasher can optionally enable energy-saving operation. According to this embodiment, the dishwasher monitors the water temperatures in a tank or boiler of the dishwasher in standby mode and ensures that a
a certain temperature that is as low as possible is not exceeded. This temperature is chosen so that when a rinsing cycle starts (ie the rinsing operation is started and a rinsing cycle is run through), the water in one Rinsing cycle with the desired (target) temperature, at the desired time and optionally (depending on the embodiment) also in the desired quantity can be provided in order to enable hygienic rinsing operation. For example, the fresh water temperature for rinsing the items to be washed in the boiler and/or the rinse water temperature in the dishwasher tank can be monitored. According to the measured temperature, the dishwasher activates and deactivates the heating of the boiler and/or tank.

In comparison to conventional dishwashers, which always keep the water temperature in the boiler and/or tank at the desired target temperatures even in standby mode, the water temperatures in standby mode are reduced to minimum temperatures. In this way, the power consumption of the dishwasher in standby can be significantly reduced and at the same time the hygienic cleaning of the items to be washed is ensured.

According to an exemplary embodiment of the invention, a dishwasher, in particular a pass-through dishwasher, is designed to operate in different

Voltage networks proposed, which includes several electrical consumer elements, a power controller, and a network input terminal with several conductors for connecting the power controller to the conductors of the on-site low-voltage network, with one phase or several phases, in particular three phases. The power controller is able to recognize the type of low-voltage network based on the single- or multi-phase network voltage of the low-voltage network supplied to the power controller. Furthermore, the power plate comprises a switching unit which electrically connects the conductors of the mains input terminal with groups of consumer elements depending on the recognized type of low-voltage network. Each group includes at least one consumer element or several consumer elements connected in parallel, and at least one switch for controlling the power supply to the consumer elements of the respective group.

In exemplary embodiments, the switching unit can have a single-stage, two-stage or multi-stage design.

In a further exemplary embodiment, a separate switch is provided for each electrical consumer element of each group. Furthermore, the power controller can be designed as a power electronics printed circuit board (PCB). It is also possible for the mains input terminal of the dishwasher to form part of the power controller. The mains input terminal and/or the connections of all consumer elements of the dishwasher can be designed, for example, as a detachable connecting element, in particular as a plug.

According to the invention, the dishwasher also comprises a measuring unit for determining the number of phases of the voltage network; and a processor unit for recognizing the type of voltage network based on the determined number of phases.

The measuring unit can, for example, be designed to determine the relative (phase) position of the phases and/or the mains voltage of the low-voltage network. The processor unit can, for example, be adapted to recognize the type of voltage network based on the determined number of phases and the relative phase position and/or the mains voltage. Which parameters are required to recognize the type of low-voltage network depends, among other things, on which low-voltage networks the dishwasher is to be used in and which differences exist between these low-voltage networks in terms of voltage, number of phases and relative phase position.

In a further exemplary embodiment, the processor unit is able to switch the switches of the switching unit and the groups of electrical consumer elements in such a way that the total current supplied to the electrical consumer elements does not exceed the protection of the low-voltage network, optionally taking into account a safety reserve. The power supply to each consumer element in at least one of the groups of electrical consumer elements can be controlled individually by the processor unit using a switch.

Furthermore, it is possible for the processor unit to use the switches of the groups of electrical consumer elements to switch the power supply to the electrical consumer elements depending on the respective process step of a washing cycle of the dishwasher.

According to a further exemplary embodiment of the invention, the processor unit of the dishwasher is adapted to read out the protection of the low-voltage network from a memory of the line controller or the dishwasher or from a coding circuit manually coded according to the protection.

In a further exemplary embodiment, the power controller comprises a memory that stores configuration information. This configuration information can, for example, indicate how the processor unit, depending on the detected (type of) low-voltage network and its protection, must cause the controller unit to switch the switches of the switching unit and the individual groups of electrical consumer elements so that the power of the low-voltage network is distributed to the electrical consumer elements of the dishwasher in such a way that the total current does not exceed the protection of the low-voltage network, optionally taking into account a safety reserve.

In addition, the resistance values of the individual electrical consumer elements of the dishwasher can also be stored in the configuration information of the memory. It is also possible for the processor unit to display the configuration information for the respective low-voltage network and its protection reads the memory and switches the switches of the switching unit based on the read configuration information. The processor unit can optionally read the voltage of the low-voltage network from a memory of the line controller or the dishwasher, for example if this can or must be entered by the user.

According to a further exemplary embodiment of the invention, the switching unit is able to switchably connect each phase of the mains voltage to a group of electrical consumer elements. In reality, this connection can look like this: If the detected low-voltage network is only a single-phase network, all consumer elements are controlled with this one phase. In a delta network with three phases, the three phases are connected to a respective group (or groups) of electrical consumer elements. In a three-phase low-voltage network with a neutral conductor, the three phases and the neutral conductor are connected to a respective group (or groups) of electrical consumer elements.

In order to enable a connection corresponding to the number of phases (and optionally also voltage) of the detected (type of) low-voltage network, the power controller can, for example, have switches to connect each phase of the mains voltage to a group of electrical consumer elements. The switches can also be designed as short-circuit switches or bridges to short-circuit the conductors of the mains input terminal of the dishwasher in accordance with the detected low-voltage network and thus supply the individual phases to the consumer elements by means of the individual (possibly short-circuited) conductors. In one embodiment of the invention, the processor unit is able to switch these switches depending on the detected type of low-voltage network in order to short-circuit individual conductors of the mains input terminal to one another and/or to connect them to the groups of consumer elements.

The switches do not necessarily have to be provided in the dishwasher as part of the power controller, but corresponding switches or bridges can alternatively be switched or set manually, e.g. when installing the dishwasher, according to the existing low-voltage network.

In a further exemplary embodiment of the invention, the power controller for the consumer elements comprises several power regulators. These can be designed as pulse width modulators, for example. The power regulators serve to reduce the (electrical) power to be delivered to the consumer elements. Each power regulator supplies the reduced power to one electrical consumer element (or optionally several).

In a further embodiment, the dishwasher can also comprise a control unit that communicates with the processor unit of the power controller via a data bus. The processor unit receives control signals for the electrical consumer elements of the dishwasher from the control unit and controls the supply of power to the respective consumer elements in accordance with the control signals. In another implementation, the functionality of the control unit can also be implemented in the processor unit of the power controller itself. If the power controller and the control unit are implemented on different electronic printed circuit boards (PCBs), it is advantageous to provide corresponding plug connections on the electronic printed circuit boards in order to be able to couple them using a data cable and thus enable communication between the control unit and the processor unit (power controller).

A further embodiment of the invention relates to a pass-through dishwasher that includes a boiler with a boiler heater for heating fresh water and a temperature sensor for determining the temperature of the fresh water in the boiler. The boiler provides fresh water for rinsing the items to be washed in a rinsing cycle. The pass-through dishwasher also has a power controller for detecting the low-voltage network to which the pass-through dishwasher is connected, as well as a temperature control unit for continuously monitoring the fresh water temperature in the boiler using the temperature sensor while the pass-through dishwasher is in standby mode. The temperature control unit also controls the power supply to the boiler heater when the pass-through dishwasher is in standby mode, so that the water temperature in the boiler does not fall below a respective predetermined minimum boiler temperature. The respective predetermined minimum boiler temperature is calculated depending on the performance of the detected low-voltage network in such a way that in a rinsing cycle the fresh water for rinsing is made available by the boiler in the desired quantity, at the desired temperature and at the desired time in the rinsing cycle in order to achieve a to enable hygienic rinsing operation.

In one embodiment of the invention, the temperature control unit corresponds, for example, to the control unit or the processor unit of the power controller of the dishwasher described above.

In a further embodiment of the invention, the pass-through dishwasher also comprises a rinsing water tank with a tank heater for heating the rinsing water and a temperature sensor for determining the temperature of the rinsing water in the rinsing water tank, as well as a circulation pump for circulating the rinsing water in the rinsing water tank during the rinsing cycle in order to clean the dishes. The temperature control unit also continuously monitors the rinsing water temperature in the rinsing water tank with the aid of the temperature sensor in the standby mode of the pass-through dishwasher, and controls the power supply to the tank heater in the standby mode of the pass-through dishwasher. such that the flushing water temperature in the flushing water tank does not fall below a respective predetermined minimum tank temperature, whereby the predetermined minimum tank temperature depends on the power of the detected low-voltage network.

Optionally, the respective specified minimum tank temperature can be selected depending on the power of the detected low-voltage network so that the rinsing water is made available from the water tank in the rinsing cycle at the desired temperature and at the desired time.

In one embodiment, the temperature control unit can, for example, prioritize the boiler heater when supplying power over the tank heater in order to ensure that in a rinsing cycle the fresh water for rinsing is delivered from the boiler in the desired quantity, at the desired temperature and at the desired time in the rinsing cycle is provided to ensure hygienic dishwashing operations. In such a case, it may happen that there is not enough "residual power" available to prevent the flushing water temperature from falling below the specified tank temperature. Alternatively, it is of course also possible to prioritize the tank heater over the boiler heater when it comes to power supply in order to ensure that the rinse water from the rinse water tank is made available in a rinse cycle at the desired temperature and at the desired time in the rinse cycle for rinsing the items to be washed to ensure hygienic dishwashing operations.

The respective specified minimum temperature of the boiler or water tank can depend on various factors/parameters. For example, the respective predetermined minimum temperature of the boiler or the water tank (in addition) can depend on at least one of the following parameters:
the maximum power that can be supplied to the boiler heater or the tank heater from the detected low-voltage network, the respective amounts of water from the boiler or water tank that are required in a rinsing cycle, the desired temperatures of the respective amounts of water from the boiler, or water tank that are required in the rinsing cycle, and the point in time in the rinsing cycle at which the respective amounts of water from the boiler or water tank should be available at the desired temperatures.

By lowering the standby temperatures in the tank and/or boiler of the dishwasher according to the method described above, energy is saved because the tank and boiler do not have to be permanently heated to the target temperatures. This minimizes thermal radiation losses in the area surrounding the dishwasher.

A further embodiment of the invention relates to a method for saving energy in a pass-through dishwasher. According to this method, the low-voltage network to which the pass-through dishwasher is connected is detected and the fresh water temperature in a boiler of the dishwasher is continuously monitored while the pass-through dishwasher is in standby mode. The boiler is equipped with a boiler heater for heating fresh water. According to the method, the power supply to the boiler heater when the pass-through dishwasher is in standby mode is controlled so that the fresh water temperature in the boiler does not fall below a specified minimum boiler temperature. The respective predetermined minimum boiler temperature is selected depending on the performance of the detected low-voltage network so that in a rinsing cycle the fresh water is made available by the boiler in the desired quantity, at the desired temperature and at the desired time in the rinsing cycle in order to ensure hygienic rinsing operation to enable.

In a further embodiment, the method can further comprise continuously monitoring the rinse water temperature in a rinse water tank of the pass-through dishwasher, wherein it is further assumed that the rinse water tank comprises a tank heater for heating the rinse water. The power supply to the tank heater is controlled in the standby mode of the pass-through dishwasher such that the rinse water temperature in the rinse water tank does not fall below a respective predetermined minimum tank temperature, wherein the predetermined minimum tank temperature depends on the power of the detected low-voltage network.

As already shown, the respective predetermined minimum tank temperature can optionally be selected depending on the power of the detected low-voltage network so that the rinsing water is made available from the water tank in the rinsing cycle at the desired temperature and at the desired time.

According to the method, according to further embodiments, it is possible to prioritize the boiler heater in terms of power supply over the tank heater in order to ensure that in a rinsing cycle the fresh water for rinsing is made available by the boiler in the desired amount, at the desired temperature and at the desired time in the rinsing cycle, so that hygienic rinsing is ensured. Alternatively, however, the tank heater can also be prioritized in terms of power supply over the boiler heater in order to ensure that in a rinsing cycle the rinsing water of the rinsing water tank is made available by the rinsing water tank for rinsing the items to be washed at the desired temperature and at the desired time in the rinsing cycle, so that hygienic rinsing is ensured.

Another embodiment of the invention is a computer-readable medium that stores instructions that, when executed by a processor unit of a pass-through dishwasher, cause the pass-through dishwasher to perform the steps of the method for energy conservation in a pass-through dishwasher according to one of the various described embodiments.

DESCRIPTION OF THE FIGURES

Fig. 1

zeigt eine gewerbliche Durchschubspülmaschine gemäß einer beispielhaften Ausführungsform der Erfindung,

Fig. 2

zeigt einen funktionserläuternden Aufbau der Durchschubspülmaschine nach Fig. 1,

Fig. 3

zeigt einen Leistungsteller gemäß einer Ausführungsform der Erfindung, der die Zuführung der Leistung aus dem Niederspannungsnetzes an eine Boilerheizung, eine Tankheizung und die Umwälzpumpe einer Spülmaschine steuert,

Fig. 4

zeigt eine beispielhafte Verschaltung der einzelnen elektrischen Verbraucherelemente in Fig. 3 in einem Sternnetz,

Fig. 5

zeigt eine beispielhafte Verschaltung der einzelnen elektrischen Verbraucherelemente in Fig. 3 in einem Wechselstromnetz, und

Fig. 6

zeigt die beispielhafte Verschaltung der einzelnen elektrischen Verbraucherelemente in Fig. 3 in einem Dreiecksnetz.

The invention is described in more detail below using embodiments with reference to the figures. Corresponding elements and details in the figures are provided with the same reference numerals.

Fig.1

shows a commercial pass-through dishwasher according to an exemplary embodiment of the invention,

Fig.2

shows a functional structure of the pass-through dishwasher according to Fig.1 ,

Fig.3

shows a power controller according to an embodiment of the invention, which controls the supply of power from the low-voltage network to a boiler heater, a tank heater and the circulation pump of a dishwasher,

Fig.4

shows an example of the connection of the individual electrical consumer elements in Fig.3 in a star network,

Fig.5

shows an example of the connection of the individual electrical consumer elements in Fig.3 in an alternating current network, and

Fig.6

shows the exemplary wiring of the individual electrical consumer elements in Fig.3 in a triangular network.

DETAILED DESCRIPTION OF THE INVENTION

One aspect of the invention relates to the design of a dishwasher, particularly for commercial use, which can be operated in different low-voltage networks. Advantageously, the dishwasher is designed in such a way that, despite the possibility of operating the dishwasher in different low-voltage networks, there are ideally no differences in the structure of the dishwasher, especially with regard to the (number of) installed radiators, pumps and power electronic components, such as the power controller.

The dishwasher according to this aspect of the invention is able to independently recognize the on-site low-voltage network to which it is connected and, based on the recognized low-voltage network, to optimally distribute the available power of the on-site low-voltage network (optionally taking a safety reserve into account) to individual electrical consumer elements the dishwasher. This makes it possible to effectively use the maximum power of the low-voltage network detected. In order to ensure this distribution of the power supplied by the on-site low-voltage network, the dishwasher includes a power controller that controls the distribution of the power from the low-voltage network. For this purpose, the power controller can include a switching unit which, depending on the low-voltage network detected, interconnects the individual phases of the low-voltage network with the electrical consumer elements. The switching unit can, as will be explained in more detail below, be designed in one or more stages.

The electrical consumer elements that are taken into account according to the invention are not necessarily all of the electrical consumer elements of the dishwasher, but for example only those that can consume significant power. For example, these are electrical consumer elements that cause a current flow in the three-digit mA range or more, such as circulating pumps or radiators, or their heating coils for boilers or rinsing water tanks. Electrical consumer elements that consume only a small amount of power, e.g. in the two-digit mA range or less, do not have to be taken into account, but can be taken into account as a general rule (e.g. through a power reserve). Electrical consumer elements that only have very little current flowing through them are, for example, solenoid valves for supplying fresh water or pumps for the rinsing chemicals, the power consumption of the power controller itself or the control electronics, etc.

The power controller can be designed as a power electronic printed circuit board (PCB). In one embodiment, the semiconductor-based power controller is designed on a power electronic circuit board, i.e. it essentially comprises power semiconductor components, such as power diodes, thyristors, triacs, power MOSFETs and/or IGTB components, which are able to handle the required currents occurring in a low-voltage network and switching voltages. Compared to the use of contactors, the use of power semiconductors in the power controller multiplies the number of switching cycles, which significantly improves the service life.

In order to detect the on-site low-voltage network to which the dishwasher is connected, the dishwasher comprises a measuring unit and a processor unit according to one embodiment. The measuring unit determines the number of phases of the on-site low-voltage network and optionally their (relative) phase position to one another and/or the voltage of the on-site low-voltage network. From the information determined on the on-site low-voltage network, the processor unit then determines which type of low-voltage network the dishwasher is connected to and configures the switching unit of the power controller in such a way that the individual phases of the detected low-voltage network are charged in such a way that they can supply corresponding electrical consumer elements with power.

Optionally, the individual conductors of the mains connection can also be protected with a fuse. It is also possible for individual information about the on-site low-voltage network to be configured manually, e.g. when installing the dishwasher. For example, the voltage of the low-voltage network and/or the on-site protection of the low-voltage network could also be configured manually. Depending on which low-voltage network the dishwasher is to be operated in, individual parameters of the low-voltage network can also be permanently configured/specified. The configuration information can, for example, be stored in a data memory of the power controller of the dishwasher, which the processor unit can access for reading and optionally also writing purposes.

In one embodiment of the invention, the power supply to each electrical consumer element can be individually controlled by the processor unit using a switch. Each phase of the on-site low-voltage network is advantageously connected to a group consisting of several electrical consumer elements, although the individual consumer elements can be supplied with power individually using the associated switch. It is also advantageously ensured that the total current that is supplied to the electrical consumer elements depending on the respective process step of the rinsing cycle does not exceed the protection of the low-voltage network, optionally taking into account a safety reserve.

In an exemplary embodiment of the invention, the electrical consumer elements of a pass-through dishwasher according to the invention, which are supplied by the power controller with power from the on-site low-voltage network, include the heating coils of the radiators for the rinse water tank and the boiler, as well as a circulation pump for circulating the rinse water in the rinse water tank. The circulation pump motor can also be controlled by a frequency converter. Optionally, additional electrical consumer elements can be provided in the pass-through dishwasher, which can also be supplied with power by the power controller. These can be, for example, solenoid valves, metering pumps for the rinsing chemicals, a pump for supplying fresh water from the boiler and/or a pump for pumping out rinsing water. As a rule, these elements consume little power compared to the radiators of the boiler or the flushing water tank and the circulation pump. It is therefore possible that these elements of the dishwasher, which only consume a small amount of power, are already taken into account as a general rule with a safety margin and therefore do not have to be explicitly taken into account by the power controller when distributing the power from the detected low-voltage network. Of course, it is also possible to take consumer elements with low power consumption into account in the distribution of the connected load of the low-voltage network; This primarily only increases the complexity of the power distribution.

The invention is described in the following paragraphs primarily with reference to a dishwasher designed for commercial use, in particular a (basket) pass-through dishwasher. However, the principles of the invention are not to be understood as being limited to use in such a pass-through dishwasher. A pass-through dishwasher according to an exemplary embodiment of the invention is in Fig. 1 shown. Fig. 2 shows a functional structure of the pass-through dishwasher Fig. 1 . The exemplary push-through dishwasher includes a washing compartment in its upper area, which is formed on the one hand by the rear wall and the rinsing water tank of the push-through dishwasher and on the other hand by the hood of the push-through dishwasher, which can be opened in an exemplary manner upwards. The washing compartment serves to hold the items to be cleaned.

The items to be washed are cleaned by circulating the wash water in the wash water tank, which is located in the lower area of the wash compartment, as in Fig. 2 can be recognized. The rinsing water tank has a radiator for heating the rinsing water and can typically hold a quantity of rinsing water of approx. 15 to 45 liters. To clean the items to be washed, the dishwasher includes a rotatable rinsing arm, which is rotatably arranged in the lower area of the washing compartment, underneath the items to be cleaned. Additionally or alternatively, a rinsing arm can also be provided above the items to be washed, as exemplified in Fig. 2 shown. Using the circulation pump, the rinsing water is pumped into the rinsing arm (or rinsing arms) and cleans the items to be washed. Furthermore, the rinsing arm can be used to rinse the items to be washed with heated clean water supplied from the boiler after the circulation phase in the rinsing cycle and at the same time to supply fresh water to the rinsing water in the tank. Alternatively, a separate rinse arm can also be provided for this purpose. Appropriate pumps (motors) for supplying the rinsing water or fresh water via the rinsing arm (or rinsing arm, if available), supplying the cleaning agent and for removing contaminated rinsing water are also provided, but in Fig. 2 only hinted at.

In a lower area of the push-through dishwasher are the control electronics (control unit) of the push-through dishwasher and the power plate, which will be discussed in more detail below, as well as the already mentioned circulation pump and the boiler. The capacity of the boiler can, for example, correspond to the amount of fresh water required for rinsing. However, it is also possible that the boiler holds more fresh water than necessary for rinsing. In this way, the amount of rinsing can be adjusted to higher and lower values to suit the items to be washed. Other conventional elements of the push-through dishwasher are not shown, such as the fresh water supply and rinse water drain, the heating of the rinse water tank and the boiler, a frequency converter for controlling the pumps or the mains connection of the on-site low-voltage network. The control unit and the power controller can be implemented on different electronic printed circuit boards (PCBs) and connected to one another via a data cable. However, it is also possible to design the control unit and the power controller in an electronic printed circuit board (PCB).

Without limiting the generality, it can be assumed by way of example that a rinsing cycle of the pass-through dishwasher only lasts a few minutes, e.g. 1, 2, 3, 4 or 5 minutes, and only a few liters of fresh water are required (e.g. 2 to 5 liters per rinsing cycle). In one embodiment, the individual process steps of the rinsing cycle of the pass-through dishwasher include, for example, the so-called circulation time (circulation phase), in which the circulation pump of the dishwasher cleans the dishes by circulating the lye in the rinsing water tank, and a post-rinse phase, in which the cleaned dishes are rinsed with fresh water. Additional phases, such as a drip break, can optionally be provided between the circulation time and the post-rinse phase. After the post-rinse phase, another drip break and/or drying phase, in which the dishes are dried, can also be provided before the rinsing cycle ends. However, the invention is not limited to these exemplary processes in a rinsing cycle.

Basically, the dishwasher according to the invention should enable the hygienic cleaning of the dishes. This means that at least in one process step of the rinsing cycle, the water must have a temperature that ensures the hygienic cleaning of the dishes. If we assume the exemplary rinsing cycle of a pass-through dishwasher described above, the dishes must either be rinsed with 2 to 5 liters of fresh water and/or the dishes must be cleaned by circulating them at correspondingly high temperatures. For rinsing, the fresh water should therefore have a temperature of 60 °C to 90 °C, advantageously 80 °C to 85 °C. In an exemplary example, the fresh water is heated to 85 °C for rinsing. If the rinsing process is intended to ensure the hygienic cleaning of the dishes, the dishes are cleaned for a certain time with rinsing water in the temperature range between 55 °C and 70 °C, advantageously between 60 °C and 65 °C. In an example, the dishes are to be washed in the circulation phase with water at a temperature of 62 °C. In addition to the temperature, a hygienic washing result can also be influenced by the duration of the wash cycle and the final rinse, by the temperatures of the wash water in the circulation phase and the fresh water in the final rinse phase, and by the washing chemicals. With particularly long washing times or when using special washing chemicals, the temperatures of the wash water and fresh water can deviate from the typical temperatures listed above as examples, and in particular can be lower.

Without limiting the generality, it can be assumed, for example, that the electrical heating elements (or, where applicable, their individually controllable heating coils) of the boiler and the rinsing water tank, as well as the circulation pump, represent the main power consumers in the dishwasher. These electrical consumer elements generally have a power consumption in the kW range, while other electrical consumers, such as electrically operated metering pumps and solenoid valves, the power controller, the control electronics, electrical operating elements or a display, etc. only require currents in the single-digit or double-digit mA range and thus only contribute insignificantly to energy consumption. Accordingly, the following exemplary embodiments primarily refer to the electrical heating elements (or, where applicable, their individually controllable heating coils) of the boiler and the rinsing water tank, as well as the circulation pump of the pass-through dishwasher, while the other electrical consumer elements do not have to be taken into account separately in the power distribution by the power controller or are taken into account by including a flat-rate power reserve in the distribution of power by the power controller.

The water in the boiler or the flushing water tank is heated electrically via radiators. For example, a tubular heater can be used as a radiator. In one embodiment, a radiator has several heating coils (e.g. 2, 3 or 4), which can have different or identical heating cables. In an exemplary embodiment of the invention, a three-coil radiator is used for the boiler and/or flushing water tank, which covers the entire mains voltage range worldwide. In an alternative embodiment, the radiator for the boiler and/or flushing water tank can also be designed as four-coiled.

A radiator, for example, can have a total heating output of up to 18 kW, although higher or lower heating outputs can also be used. In an exemplary implementation, the individual heating coils of the radiator can be controlled individually by the power controller. Each coil of the radiator can have a different resistance and therefore delivers different power with the same mains voltage. If the heating coils can be switched individually, this results in a variety of heating outputs that can be adjusted using the control panel. Depending on the customer's available mains connection power and the operating status of the machine (standby mode or rinsing mode, but also different phases in the rinsing cycle), different heating lines can be switched on by the power controller. This also takes into account how the switching unit distributes the groups of consumer elements to the individual phases of the network connection.

This makes it possible to install only a very small number of different radiators in the pass-through dishwashers, ideally only a single type of radiator, which significantly increases the machine variants, i.e. by up to 80%, through network-independent worldwide (or at least in the desired target countries) usability the power electronics and the controlled radiators.

Furthermore, in one embodiment of the invention, it is possible to connect the radiators to the power controller using plugs (and possibly cables). Plugging the radiators onto the power controller simplifies and speeds up the assembly process compared to screwing them to the contactors.

The power controller can optionally also enable the electrical power to be distributed between the boiler and the flushing water tank, or between the boiler heating elements, using half-wave control. The heating power in the flushing water tank and boiler can therefore be adjusted very precisely, which enables the temperatures in the flushing water tank and boiler to be precisely controlled. Alternatively, the individual consumer elements can also be controlled using pulse width modulation to control their power consumption.

The control unit of the pass-through dishwasher can, for example, use a bus to transmit to the power controller which heating coil is switched on and how the power is distributed between the individual heating coils (half-wave control). The software of the processor unit, e.g. a microcontroller, of the power controller controls the power semiconductors and ensures, for example, that they switch at zero voltage and that switching between different heating coils takes place with as little flicker as possible.

Fig.3 shows a power controller according to an embodiment of the invention, which controls the supply of power from the low-voltage network to a boiler heater with four heating coils, a washing tank heater with one heating coil and to a circulation pump. The power supply to the circulation pump UP can optionally be interrupted with a safety relay 305, e.g. to prevent the pump from circulating the washing water when the hood/door of the dishwasher is opened. The power controller 300 of the dishwasher has a mains input terminal 301, which is designed as a plug connector and is connected to the on-site network. In the example shown, the mains input terminal 301 is designed as a 4-pin plug and accordingly four conductors are fed to the configuration switching unit 302. The conductors are designated L1, L2, L3 and N, where N is the neutral conductor and up to three phases of the low-voltage network are connected to the conductors L1, L2, L3. However, it is also possible to provide an additional PE (Protective Earth) conductor and to design the mains input terminal 301 as a five-pin plug.

A measuring device 303 is in Fig.3 connected to conductors L1, L2, L3 and N in front of the configuration switching unit 302. The measuring device 303 measures for each of the three conductors L1, L2, L3 whether a phase of the on-site low-voltage network is connected to it and, if so, the phase difference between the individual conductors. Furthermore, the measuring device 303 can also record the voltage applied to the respective conductors L1, L2, L3. Using these measured variables, the processor unit 307 can determine which type of low-voltage network has been connected to the network input terminal. The processor unit 307 can thus differentiate between single-phase and three-phase low-voltage networks, recognize the voltage of the low-voltage network and, based on the phase differences, recognize whether it is a three-phase star network (with neutral conductor) or a delta network (without neutral conductor).

When installing the dishwasher in a single-phase low-voltage network, the one phase of the network connection 301 can only be connected to one of the conductors L1, L2, L3 (e.g. conductor L1). In this case, the measuring device 303 recognizes the single-phase on-site low-voltage network because only one of the conductors (e.g. L1) has an alternating voltage. If the processor unit 307 recognizes a single-phase low-voltage network based on the measurement results of the measuring device 303, it causes the configuration switching unit 302 to connect all groups of consumer elements to the one phase.

If the dishwasher is connected to a three-phase low-voltage network, it can be a star network (L1, L2, L3 and N connected) or a delta network (L1, L2 and L3 connected). The measuring unit compares the phase positions of the star voltages U _L1-N , U _L2-N and U _L3-N with each other. If the neutral conductor is not connected, it runs synchronously with one of the phases L1, L2 or L3 via a circuit in the measuring unit 303. The measuring unit 303 uses the phase position to calculate whether it is a delta network or a star network.

In another embodiment, the configuration switching unit 302 can also be implemented "manually". For this purpose, instead of processor-controlled configuration switches, (short-circuit) terminals are used manually when installing the dishwasher in order to achieve the necessary connection of the conductors L1, L2, L3 and N according to the network type. In a single-phase voltage network, the conductors L1, L2 and L3 are short-circuited using short-circuit terminals or bridges so that the same phase is present on all three conductors of the network connection. In this case, the processor unit 307 can recognize that it is a single-phase voltage network based on the measurement results of the measuring device 303, i.e. based on the non-existent phase difference (phase difference = 0).

For a star network, no short-circuit terminals or bridges need to be provided, so that the measuring device 303 can detect the network type as described above. For a delta network, on the other hand, the conductors L1, L2, L3 and N are connected using short-circuit terminals or bridges so that the (groups of) consumer elements are connected as shown in Fig.6 shown are connected to the phases, ie the neutral conductor (not present on site) is not used.

Optionally, it would also be conceivable that the plug of the connection cable already correctly transfers the individual phases to the power connection terminal of the dishwasher.

If short-circuit jumpers are set when installing the dishwasher (or a correspondingly configured plug is used), it should be noted that the measuring device 303 can only be connected to the individual conductors L1, L2, L3 and N after these. Accordingly, in this case, the set bridges must be taken into account by the measuring device 303 when recognizing the network type.

In the Fig.3 In the example shown, if a star network is detected (and thus a neutral conductor is present), the processor unit 307 causes the configuration switching unit 302 to switch the configuration switches 312 so that they connect the switches T1-T6 of the switching unit 304 to the neutral conductor N. If a delta network is detected (and thus no neutral conductor is present), the processor unit 307 causes the configuration switching unit 302 to switch the configuration switches 312 so that they connect the switches T1, T2, T4, T5 and T6 of the switching unit 304 to the conductor L3 and T3 to L2. Furthermore, the processor unit 307 causes the configuration switching unit 302 to connect the conductors L1, L2, L3 and N (star network) or conductors L1, L2 and L3 (delta network) to the electrical consumer elements, ie in the exemplary embodiment to the heating coils of the radiators and the circulation pump.

Fig.4 shows an example of the connection of the electrical consumer elements, ie the four coils (B1.1, B1.2, B1.3 and B1.4) of the boiler heater, the coil (T1.1) of the flush tank heater and the circulation pump in Fig.3 in a star network. Fig.5 shows an example of the connection of the electrical consumer elements, ie the four coils (B1.1, B1.2, B1.3 and B1.4) of the boiler heater, the coil (T1.1) of the flush tank heater and the circulation pump in Fig.3 in an alternating current network. Fig.6 shows the connection in a delta network. The switches T1 to T6 show the individual switches of the switching unit 304 in Fig.3 .

The connection of the configuration switches S1-S4 of the configuration switching unit 302 corresponding to each detected low-voltage network can, for example, be stored at the factory in a memory device 308 of the power controller (e.g. a ROM, EEPROM, or another readable and optionally writable non-volatile memory). The processor unit 307 can then read out the corresponding configuration information for the configuration switches S1-S4 from the memory unit 308 depending on the detected low-voltage network and cause the configuration switching unit 302 to switch the configuration switches S1-S4 accordingly.

As in Fig. 3 As can be seen, the conductors L1, L2, L3 and the neutral conductor N (if present on site) are connected to the electrical consumer elements in such a way that each of the conductors L1, L2 and L3 and the neutral conductor N (if present on site) is connected to a group of several consumer elements is connected. Each consumer element can also be switched via a switch of the switching unit 304, whereby the respective switch of the consumer element can be opened and closed by the processor unit 307. This allows the processor unit 307 to individually control the current flow through the individual consumer elements. This enables the processor unit 307 to control the power supply to the consumer elements in a targeted manner adapted to the individual process steps of a flushing cycle and at the same time to ensure that the power consumed by the consumer elements does not exceed the maximum power provided by the detected low-voltage network (optionally minus a power reserve).

The table below shows, for various networks, examples of how the consumer elements of the tank heater, boiler heater and circulation pump are switched when the boiler is prioritized and there is a corresponding heating requirement. Other combinations are also conceivable. The following outputs of the individual heating elements and the circulation pump are assumed at a voltage of 230 V _eff . The tank heater has one coil (consumer elements) T1.1 = 2.5 kW. The boiler heater has four coils (consumer elements) B1.1 to B1.4, with the individual outputs B1.1 = 3 kW, B1.2 = 1.8 kW, B1.3 = 3 kW and B1.4 = 3 kW. The circulation pump (consumer element) UP has an output of 1.5 kW. <b>Table 2</b> Type of network Circulation phase (priority and heating requirement in the boiler) Standby (priority and heating requirement in the boiler) Three-phase star network, 400 V, 16 A UP, B1.2, B1.3, B1.4 B1.1, B1.3, B1.4 Three-phase star network, 400V, 32 A UP, B1.1, B1.2, B1.3, B1.4, T1.1 B1.1, B1.2, B1.3, B1.4, T1.1 Single-phase AC, 230 V, 32 A UP, B1.2, B1.3 B1.3, B1.4

Here, too, it is possible to store the respective switch positions of the switches of the switching unit 304 in the power controller's memory device for the respective available power in the various types of low-voltage networks and for the various process steps in the rinsing cycle. Here, too, the processor unit 307 can read the corresponding switching information for the switches T1-T6 of the switching unit 304 from the memory unit 308 depending on the detected low-voltage network and the respective process step in the rinsing cycle and cause the switching unit 304 to switch the switches T1-T6 of the switching unit 304 accordingly.

The respective power available in the different types of low-voltage networks depends on the number of phases and the network voltage and on the protection of the low-voltage network, i.e. the maximum current flow per phase. The protection of the phases can be specified, for example, by a coding circuit when installing the dishwasher. Alternatively, the protection can also be programmed by the user of the dishwasher and is stored in the memory device. The processor unit 307 is able to read out the coding circuit or to read out the protection of the phases from the memory device in order to determine the respective maximum power (per phase) of the detected low-voltage network. According to the power determined in this way (per phase), the processor unit 307 can read out the corresponding switch positions of the switching unit 304 for the respective process steps of the rinsing cycle from the memory unit 308 and cause the switching unit 304 to open or close the switches of the switching unit 304 accordingly.

It is also possible that the level of the mains voltage can be specified by a coding circuit when the dishwasher is installed or alternatively can be programmed by the user of the dishwasher and stored in the memory device. In this case, it is not necessary for the measuring device 303 to determine the mains voltage of the on-site low-voltage network, but the value can be read by the processor unit 307 from the coding circuit or the memory device 308.

In another embodiment, it is possible to dispense with the measuring device 303 entirely. In this case, the type of low-voltage network to which the dishwasher is connected, as well as its network voltage and fuse protection, is set using one or more coding circuits and read by the processor unit 307 in order to switch the configuration switching unit 302 and switching unit 304 according to the encoded information. Alternatively, instead of the coding circuit(s), the information can be programmed by the user of the dishwasher and stored in the memory unit of the power controller. The processor unit 307 can then read out this information and control the configuration switching unit 302 and switching unit 304 accordingly.

The in Fig. 3 Shown exemplary power plate 300 according to an embodiment of the invention is provided with a two-stage switching arrangement. The first stage corresponds to the configuration switching unit 302, which connects the lines L1, L2, L3 and N of the network connection to the electrical consumer elements depending on the detected low-voltage network. The second stage corresponds to the switching unit 304 and makes it possible to control the power supply to the individual consumer elements using their switches T1-T6. In another embodiment it is intended to implement these two stages in a single switch arrangement. For this purpose, the power plate 300 includes, instead of the configuration switching unit 302 and switching unit 304, a switching matrix with switches that allow each electrical consumer element to be connected to one of the conductors L1 depending on the detected low-voltage network (and its provided power) and depending on the process step of the flushing cycle , L2 and L3 and the neutral conductor (star network and single-phase AC network) or with two of the conductors L1, L2 and L3 (delta network).

The configuration of the power controller and in particular the way in which the configuration switching unit 302 and the switching unit 304 are switched by the processor unit 307 depends, as explained, on the number and the individual power of the consumer elements taken into account, as well as on the low-voltage network to which the dishwasher is connected (network type, voltage and fuse). Of course, the invention is not limited to the Fig.3 shown number of consumer elements, in particular limited to a 4-coil boiler heater and a 1-coil tank heater. The boiler heater and tank heater can also have more or fewer heating coils (and thus consumer elements). This can lead to the power controller 300 not being able to be implemented on a single power electronics printed circuit board (PCB), but rather to several power controllers, which in turn can control different groups of consumer elements, being used in a cascade. For this purpose, the individual phases of the low-voltage network can be connected to the network connection terminal 301 of the parallel-connected power controllers 300.

In the case of cascading several power controllers, the control electronics (control unit) can be implemented on its own electronic printed circuit board (PCB) and transmit the necessary control information for controlling the configuration switching units 302 and the switching unit 304 to the power controllers or their processor units 307 via a data bus . The power controllers are connected to the control unit using data cables (see data bus connection 306).

A further aspect of the invention relates, as already mentioned, to an energy-saving operation of a (commercial) dishwasher, for example in relation to Fig. 1 to 3 was described. The dishwasher monitors In standby mode, the temperature of the water required in a washing cycle, which is provided by a tank or boiler of the dishwasher and ensures that the water temperature does not fall below a certain predetermined temperature. This temperature is chosen so that when a rinse cycle starts (ie the rinse operation is started and a rinse cycle is run through), the water during the rinse cycle is at the desired (target) temperature, at the desired time and optionally (depending on the embodiment) also in the desired amount can be made available to enable hygienic dishwashing operations. For example, the fresh water temperature for rinsing the items to be washed in the boiler and/or the rinse water temperature in the dishwasher tank can be monitored. According to the measured temperature, the dishwasher activates and deactivates the heating of the boiler and/or rinse water tank.

Commercial dishwashers usually have short wash times of just a few minutes. For example, one can assume that hygienic cleaning of the items to be washed is ensured by rinsing the items to be washed with hot water from the boiler at the end of a washing cycle. Due to the very short rinsing times, the fresh water in the boiler has to be heated from the power water temperature (approx. 5°C - 25°C) to the desired temperature, approx. 85°C, in a correspondingly short time, which is why conventional dishwashers use the temperature of the water in the boiler as much as possible continuously, i.e. maintain a water temperature of 85° C even in standby mode. Likewise, in conventional dishwashers, the water temperature in the dishwasher compartment is kept at the desired temperature, e.g. approx. 62 °C, in order to be able to start and complete the washing process as quickly as possible.

The dishwasher according to one embodiment of the invention allows the temperatures of at least the fresh water in the boiler and optionally also the rinse water in the tank to be lowered during the standby time of the dishwasher and not fall below certain minimum temperatures.

If you look at the temperature specified for the fresh water, which must not be undercut, this is chosen so that when a rinse cycle starts, the rinse cycle can be started immediately and completed in the desired time, but hygienic cleaning is still ensured by rinsing with sufficiently heated water (e.g. 85 °C). The specified temperature is chosen so that the boiler can provide fresh water in the desired amount and at the desired temperature at the start of the rinsing phase in the rinse cycle (or at least for a sufficient time within the rinsing phase). If, for example, you assume a rinsing cycle of 2 minutes and, by way of example, that the rinsing including the dripping break takes 16 seconds and 2 litres of hot fresh water are required, the specified temperature, which must not be undercut, is chosen so that the boiler heats the amount of water in the boiler to the desired temperature of 85 °C within 104 seconds.

Depending on the boiler volume selected, residual water may remain in the boiler after the fresh water has been removed for the rinsing phase. This in turn means that the specified temperature for the fresh water, which must not be undercut, may be higher with a smaller boiler volume than with a larger boiler volume. However, for safety reasons (e.g. to avoid overheating/burning out of the boiler heating), it may still be advisable to select a boiler volume larger than the amount (volume) of fresh water required in the rinsing phase, for example to ensure that the heating coils always remain in the (residual) water. Accordingly, the boiler volume can be selected so that, regardless of the selected rinsing quantity, the residual water quantity in the boiler after rinsing is constant (e.g. 4.5 1).

The value of the specified fresh water temperature, which should not be undercut, depends, among other things, on the power that can be made available to the radiator during the available time period (i.e. in the previous example, in the 104 seconds). This power can also depend, among other things, on the maximum power of the low-voltage network (i.e. voltage, number of phases and their protection). Of course, the capacity of the boiler and the amount of residual water remaining in the boiler, the power of the boiler heater or its coils, the amount of water required, and the time period available to heat the fresh water also influence the specified temperature, which should not be undercut.

For a dishwasher like this in terms of Fig. 1 to Fig. 3 As described, the table below shows an example for a selection of different power levels in the low-voltage network, which temperature the fresh water should not fall below in standby mode, so that 2 or 3 liters of fresh water are available for the rinsing phase at 85 °C, which begins 104 seconds after the start of the cycle can be. Table 3 below assumes that a residual amount of water of 4.5 liters always remains in the boiler after rinsing. Accordingly, after refilling the boiler, there are 6.5 1 and 7.5 1 of fresh water in the boiler, which must be heated and then should not fall below the minimum temperatures shown in Table 3. <b>Table 3</b> Type of network Tension validation Minimum temperature of the water in the boiler, rinse quantity 2.01 Minimum temperature of the water in the boiler, rinse quantity 3.01 Three-phase star network 400V 16 A 54 60 Three-phase star network 400V 25 A 50 55 Three-phase star network 400V 32 A 43 49 Single-phase alternating voltage 230V 32 A 67 70

As indicated, it can optionally also be ensured that the washing water has a certain temperature, e.g. 62 °C, for a certain time within the circulation time of the dishwasher. For this purpose, for example, a certain rinsing water temperature can be specified, which should not be fallen below in standby mode, so that the rinsing cycle can be started immediately and the rinsing water is still available at the desired time in the rinsing cycle at the desired temperature. Returning to the example above, it can be assumed, for example, that the circulation time lasts 104 seconds. Accordingly, the certain rinsing water temperature that should not be fallen below in standby mode can be selected so that at least for a certain time, e.g. 15, 30 seconds or 45 seconds, of the circulation time, the rinsing water has (at least) a certain temperature, e.g. 62 °C. Similar to what is shown in Table 3, the respective minimum flushing water temperatures that should not be fallen below in standby mode can be determined for different low-voltage networks (and optionally for different amounts of flushing water).

The fresh water is often supplied at a temperature below the specified minimum temperature of the fresh water in the boiler. If the mains connection power is low, it may happen that the temperatures required by the user for washing cannot always be reached at the desired times if the next washing cycle is started immediately after the end of a washing cycle. In such a case, the dishwasher can extend the washing cycle or one or more process steps in which a desired temperature is to be reached until the desired temperatures are reached.

• Netzspannung und Absicherung am Installationsort (beim Kunden),
• Die aktuellen Temperaturen und die gewünschten Zieltemperaturen in Boiler und Spülwassertank,
• Energieverbrauch weiterer Aggregate wie Pumpenmotoren und Wärmepumpen,
• Zeitpunkte, zu denen das Wasser mit den gewünschten Zieltemperaturen im Spülzyklus bereitstehen soll, d.h. die Spülzeiten und Spülprogramm (Spülzyklus)
• Nachspülmenge bzw. Spültankinhalt,
• Restwassermenge, die nach dem Nachspülen im Boiler verbleibt,
• Konfiguration der Spülmaschine durch den Benutzer,
• Einhaltung von EMV Normen, z. B. Netzflicker

When determining the respective temperatures below which the fresh water in the boiler or the rinse water in the rinse tank should not fall, the following dependencies are taken into account in one embodiment of the invention:

• Mains voltage and fuse protection at the installation site (at the customer),
• The current temperatures and the desired target temperatures in the boiler and rinse water tank,
• Energy consumption of other units such as pump motors and heat pumps,
• Times at which the water with the desired target temperatures should be available in the rinsing cycle, i.e. the rinsing times and rinsing program (rinsing cycle)
• Rinse quantity or rinse tank content,
• Amount of residual water remaining in the boiler after rinsing,
• Configuration of the dishwasher by the user,
• Compliance with EMC standards, e.g. mains flicker

The energy management and temperature control of the dishwasher can be carried out either by the processor unit 307 of the power controller 300 or by the control unit of the dishwasher. If the control unit is used for this purpose, it transmits the necessary control information via data bus to the power controller or its processor unit 307, which takes over the control of the switching unit 304 accordingly. In Fig. 3 a bus connection 306 is indicated, which enables communication between the processor unit 307 and the control unit (cf. Fig. 1 and Fig. 2 ) enables.

As discussed in connection with Table 2, for a given low-voltage network there can be different combinations in which the consumer elements of the dishwasher can be operated in the individual process times of the washing cycle (e.g. circulation phase and rinsing phase) without using the maximum power provided by the low-voltage network ( if necessary, minus a safety margin). If hygienic rinsing is to be achieved by rinsing with clear water, it makes sense to use the boiler heater to prioritize the power supply over the tank heater. In this way it can be ensured that the fresh water for rinsing is provided by the boiler in the desired quantity, at the desired temperature and at the desired time in the rinsing cycle.

However, if hygienic rinsing is to be made possible by a sufficiently high temperature of the rinsing water, then it makes sense to prioritize the tank heater over the boiler heater when it comes to power supply. This ensures that in a rinsing cycle the rinsing water from the rinsing water tank is made available at the desired temperature and at the desired time in the rinsing cycle from the rinsing water tank for rinsing the items to be washed.

Claims (14)

1. A dishwasher for operation in different voltage systems, comprising:

   a plurality of electrical load elements (B1.1-4; T1.1),

   a power controller, and

   a system input terminal (301) having a plurality of conductors (L1, L2, L3, N) for connecting the power controller to the conductors of the low-voltage system of the building with one phase or a plurality of phases, in particular three phases;

   characterised in that the power controller comprises:

   - means for detecting the type of the low-voltage system on the basis of the single-phase or multi-phase system voltage of the low-voltage system of the building supplied to the power controller; and

   - a switching unit (302) for electrically connecting the conductors of the system input terminal (301) to groups of the load elements depending on the detected type of the low-voltage system, wherein each group comprises at least one load element or a plurality of load elements connected in parallel to one another, and at least one switch (T1-T6) for controlling the power supply to the load elements of the respective group;

   wherein the means for detecting the voltage system comprises:

   - a measuring unit (303) for determining the number of phases of the low-voltage system of the building; and

   - a processing unit (307) for detecting the type of the low-voltage system based on the determined number of phases.
2. The dishwasher according to claim 1,

   wherein the measuring unit (303) is adapted to determine the relative position of the phases and/or the system voltage of the low-voltage system, and

   the processing unit (307) is adapted to detect the type of the low-voltage system based on the determined number of phases, and based on the relative phase position and/or the system voltage.
3. The dishwasher according to claim 1 or 2, wherein the processing unit (307) is adapted to switch the switches (T1-T6) of the groups of electrical load elements such that the total current supplied to the electrical load elements does not exceed the protection of the low-voltage system, optionally taking into account a safety reserve,
   wherein the power supply to each load element in at least one of the groups of electrical load elements can be individually controlled with a switch (T1-T6) by the processing unit (307).
4. The dishwasher according to claim 3, wherein the processing unit (307) is adapted to switch the power supply to the electrical load elements by means of the switches (T1-T6) of the groups of electrical load elements depending on the process step of the respective washing cycle of the dishwasher.
5. The dishwasher according to one of claims 1 to 4, wherein the processing unit is adapted to read out the protection of the low-voltage system from a memory of the line controller or the dishwasher, or a coding circuit manually coded according to the protection.
6. The dishwasher according to one of claims 1 to 5, wherein the power controller comprises a memory (308) which stores configuration information which indicates how the processing unit (307), depending on the detected type of the low-voltage system and its fusing, must cause the switching unit (304) to switch the switches (T1-T6) of the individual groups of electrical load elements so that the power of the low-voltage system of the building is distributed to the electrical load elements of the dishwasher such that the total current does not exceed the fusing of the low-voltage system, optionally taking into account a safety reserve.
7. The dishwasher according to claim 6, wherein the memory (308) stores the resistance values of the individual electrical load elements of the dishwasher.
8. The dishwasher according to one of claims 6 or 7, wherein the processing unit (307) is adapted to read out configuration information from the memory (308) for the respective detected low-voltage system and its protection and to switch the switches of the setting unit based on the read-out configuration information,
   wherein the processing unit (307) is adapted to read out the voltage of the low-voltage system from a memory (308) of the line controller or the dishwasher.
9. The dishwasher according to one of claims 1 to 4, wherein the switching unit (302) is adapted to switchably connect each phase of the system voltage to a group of electrical load elements.
10. The dishwasher according to claim 9, wherein the switching unit (302) has switches (S1-S4) for connecting each phase of the system voltage to a group of electrical load elements, and
    wherein the processing unit (307) is adapted to switch the switches (S1-S4) depending on the detected type of the low-voltage system so as to electrically connect the conductors of the system input terminal (301) to groups of the load elements depending on the detected type of the low-voltage system.
11. The dishwasher according to one of claims 1 to 10, wherein the switching unit (302) further comprises switches for short-circuiting individual conductors of the system input terminal (301), and the processing unit (307) is adapted to switch the switches depending on the detected type of the low-voltage system so as to short-circuit individual conductors of the system input terminal (301) to one another.
12. The dishwasher according to one of claims 1 to 11, wherein the power controller for the load elements comprises a plurality of power controllers, in particular a pulse width modulator, for reducing the power to be output to the load elements, wherein each power controller is adapted to supply the reduced power to one or more of the electrical load elements in each case.
13. The dishwasher according to one of claims 1 to 12, wherein the dishwasher further comprises a control unit which communicates with the processing unit (307) of the power controller via a data bus, and
    the processing unit (307) is adapted to receive control signals for the electrical load elements of the dishwasher from the control unit, and to control the supply of power to the respective load elements according to the control signals.
14. The dishwasher according to one of claims 1 to 13, wherein the system input terminal (301) and/or the respective connections of the load elements of the dishwasher are designed as a releasable connecting element, in particular as a plug.

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