WATER-BEARING ELECTRICAL DEVICE AND A METHOD FOR OPERATING A WATER-BEARING ELECTRICAL DEVICE

Description

[0001] The invention relates to a water-bearing electrical device and a method for operating a water-bearing electrical device. In particular, the invention relates to a water-bearing electrical device with an electrochemical cell configured to generate a bleaching agent in situ, and a method for operating the water-bearing electrical device. For the sake of simplicity, the water-bearing electrical device is hereinafter also referred to as the device.

[0002] Bleaching agents such as hydrogen peroxide have good cleaning properties, but are only conditionally stable and have a limited shelf life in solutions. Therefore, it is necessary to prepare such a bleaching agent in situ before use in the water-carrying electrical device if items inside it are to be cleaned.

[0003] A prior art document, not documented in print, reveals a water-bearing electrical device in the form of a washing machine that contains an electrochemical cell for generating bleach in situ during a washing cycle. The problem, however, is that integrating the electrochemical cell requires space, which is limited in water-bearing electrical devices, and also increases manufacturing costs. It would therefore be advantageous to save both space and costs.

[0004] Other devices of this type are described in WO 2009 / 106406 A1 and WO 2012 / 017445 A1.

[0005] The invention thus addresses the problem of providing a water-carrying electrical device and a method for operating a water-carrying electrical device that are cost-effective and require little installation space.

[0006] According to the invention, this problem is solved by a water-carrying electrical device with the features of claim 1 and a method with the features of claim 9. Advantageous embodiments and further developments of the invention are described in the following dependent claims.

[0007] The advantages achievable with the invention, besides its cost-effectiveness, lie in the fact that the electrochemical cell serves not only to generate the bleaching agent but also as a heating element. Thus, the electrochemical cell fulfills multiple functions. This eliminates the need for a separate and additional heating element, saving on the component typically found in such devices. This, in turn, saves space and reduces costs.

[0008] The invention relates to a water-bearing electrical device with a water absorption element, an electrochemical cell with electrodes configured to produce a bleaching agent when it contains a salt-containing solution and a DC voltage is applied to the electrodes, a pump configured to transfer fluid located in the electrochemical cell from the electrochemical cell to the water absorption element, and a control unit configured to selectively apply both DC and AC voltage to the electrochemical cell.

[0009] The device is relatively simple and requires relatively little installation space because, in addition to generating bleach when a direct current is applied, the electrochemical cell also functions as a heating element when an alternating current is applied. In other words, a single component, the electrochemical cell, performs the functions of generating bleach (such as hydrogen peroxide), heating the fluid within the cell, and generating steam from an aqueous solution. The heating power of the electrochemical cell can be controlled by its composition and, if necessary, by the amount of water added, whereas a standard heating element has a fixed heating output. This allows the device to be reprogrammed for different power supplies.Adjustments based on the amount of electricity available in the grid are also possible. This allows the device to be part of a smart grid. Furthermore, standard heating elements in water-bearing appliances become scaled up over time, while scaling of the electrochemical cell is prevented or at least minimized by flushing.

[0010] In a preferred embodiment, the control unit includes a relay configured to switch between direct and alternating current. Preferably, the control unit includes control electronics. Preferably, the application of the direct or alternating current is controlled by the control electronics of the control unit. The geometry with different electronic control methods further reduces the installation space and costs.

[0011] Preferably, the control unit further comprises a rotary relay configured to connect a grounded neutral conductor to an electrode of the electrochemical cell, which is located at an inlet and an outlet of the electrochemical cell. The rotary relay is preferably controllable by the control electronics such that the conductor, with a low voltage relative to ground (neutral potential), can be connected to the electrode of the electrochemical cell located at the inlet and outlet of the electrochemical cell. This ensures that only small leakage currents can flow through the water during operation. This increases the operational reliability of the device. The electrode of the electrochemical cell located at the inlet and outlet of the electrochemical cell is preferably the anode.

[0012] Preferably, the control unit has a protective earth connection configured such that the polarity of the supply voltage can be determined. The polarity of the supply voltage is preferably determined by the control electronics. Preferably, a mains voltage, typically alternating current, is supplied to the control electronics and serves as the power supply. To generate the bleaching agent, a direct current voltage, preferably a low-voltage DC voltage, is generated from the mains voltage and applied by the control electronics to the cathode and anode, which are the electrodes of the electrochemical cell.

[0013] The control electronics are preferably designed to appropriately control the rotary relay for heating the fluid in the electrochemical cell, thus providing alternating voltage, and then to switch on the heating via the relay. The anode potential is then fed back to the control electronics. The control electronics are further configured to switch off the heating if a critical voltage occurs at the anode relative to the protective earth potential.

[0014] The salt-containing solution can contain one or more salts designed to increase the conductivity of water. In a preferred embodiment, the device includes a dosing unit configured to dispense the salt-containing solution into the electrochemical cell. The dosing unit can further be configured to dispense a detergent into the electrochemical cell. This is particularly advantageous if the bleach is used not only to clean the interior of the device but also to clean items located inside the device. For example, the device is a washing machine, and the items are textiles in the form of laundry to be washed. The detergent can be a commonly used detergent for washing or treating laundry, such as a heavy-duty detergent, a delicate detergent, fabric softener, stain remover, cleaning agent, etc.The dosing unit can have multiple chambers to dose different detergents into the electrochemical cell simultaneously or sequentially. Preferably, the dosing unit includes a dosing pump configured to pump the salt-containing solution and / or the detergent from the dosing unit into the electrochemical cell. The detergent can be the salt-containing solution, which then contains, in addition to the salt, other surfactants.

[0015] In a preferred embodiment, the device further comprises a circulation system for directing water from a first region of the water receiving element to a second region of the water receiving element, wherein the circulation system includes a circulation pump configured to pump water from the first region through the electrochemical cell into the second region. This allows the bleach generated in the electrochemical cell to be circulated through the water receiving element and the electrochemical cell.

[0016] Position and direction specifications refer to the device's standard operating position. The first area of ​​the water intake element is preferably a lower area, and the second area of ​​the water intake element is preferably an upper area.

[0017] Preferably, an inlet and an outlet of the electrochemical cell are arranged at an upper part of the electrochemical cell, wherein the inlet is connected to the pump and the outlet is connected to a line which is designed to supply fluid passed through it to the water receiving element such as the second area of ​​the water receiving element.

[0018] In a preferred embodiment, the electrochemical cell is connected via a drain valve to a point in a water supply system located upstream of a drain pump designed to remove water from the device. This provides a simple means of cleaning the electrochemical cell. It allows the electrochemical cell to be flushed and the water flushed through the electrochemical cell to be removed from the water supply system and the device. This allows the electrochemical cell to be freed from limescale and dirt. For this purpose, the drain valve is opened, and the water flowing from the electrochemical cell is removed by the drain pump. Ideally, this pumping is combined with a cleaning process performed by the device. The water supply system can be a recirculating system.

[0019] Preferably, the water-carrying electrical device is connectable to a water supply, and the control unit is configured to automatically control the water supply from the water supply to the water receiving element, preferably in the first area. The device preferably has a controllable valve and a supply line between the water supply and the water receiving element.

[0020] The water-using electrical appliance is, for example, a household appliance used commercially or privately. Preferably, the appliance is a washing machine, dishwasher, coffee machine, or steam cooker. Depending on the type of appliance, the bleach produced can be used exclusively for cleaning the interior of the appliance or alternatively or additionally for cleaning items located inside the appliance.

[0021] In a preferred embodiment, the water-carrying electrical device is designed as a washing machine and the water intake element is designed as a tub.

[0022] The bleaching agent produced is preferably peracetic acid or hydrogen peroxide. Hydrogen peroxide is preferred. Preferably, the electrochemical cell size is designed to accommodate the amount of bleach required in a cleaning process. The cathode and anode areas are, for example, 10 to 200 cm² each.

[0023] Preferably, the water connections, and more preferably the inlet and outlet of the electrochemical cell, are made of metal and grounded. This further increases the operational reliability of the device.

[0024] Furthermore, the invention relates to a method for operating a water-carrying electrical device with a water absorption element, an electrochemical cell with electrodes configured to generate a bleaching agent when it contains a salt-containing solution and a direct voltage is applied to the electrodes, a pump configured to pump fluid located in the electrochemical cell from the electrochemical cell into the water absorption element, and a control unit, wherein the method comprises the following steps a) Supplying a salt-containing solution to the electrochemical cell; b) following step a) applying direct current to the electrodes of the electrochemical cell for a predetermined period of time to generate the bleaching agent in the electrochemical cell; c) following step b) applying alternating current to the electrodes of the electrochemical cell for a predetermined period of time to heat the fluid located in the electrochemical cell; and d) pumping the fluid from the electrochemical cell into the water absorption element.

[0025] In step a), the dosing unit preferably doses the salt-containing solution and optionally detergent into the electrochemical cell in a predetermined quantity. The salt can be part of a detergent.

[0026] In step b), the salt-containing solution supplied in step b) is subjected to a direct current voltage, for example between 1 and 50 V, which is applied to the electrodes, i.e., the anode and the cathode, so that a current preferably of 1 to 20 A flows. This causes the chemical reaction or electrolysis to take place, and the bleaching agent, for example H₂O₂, is produced.

[0027] Step c) is preferably carried out once the chemical reaction has completed, i.e., once step b) is finished. Step c) serves to heat the fluid inside the electrochemical cell. This further enhances the cleaning effect of the bleach produced in step b). Preferably, an AC mains voltage, e.g., 230 V AC, is applied to the anode and cathode of the electrochemical cell. For this purpose, a relay preferably switches from the DC voltage, particularly low-voltage DC, to the mains voltage. Preferably, the way the mains plug is inserted is evaluated, and the rotary relay ensures that the grounded neutral conductor is connected to the electrode located at the inlet and outlet of the electrochemical cell, such as the anode. This ensures that only minimal leakage currents can flow through the water, thus meeting all safety requirements.

[0028] In step d), the fluid is pumped from the electrochemical cell into the water absorption element. This performs a cleaning process on the water absorption element and / or any objects within it. Steps c) and d) can be performed simultaneously. Alternatively, step c) can be performed before step d).

[0029] Preferably, water is added to the electrochemical cell. This step serves, in particular, to add the required amount of water for the cleaning process and / or to dilute the bleach concentrate produced in the electrochemical cell. If the device is a washing machine, the required amount of water depends, for example, on the amount of laundry, i.e., its load as determined by the machine. Mixing the concentrate in the electrochemical cell with the water reduces the conductivity of the solution, so that when the AC voltage from the mains is applied to the anode and cathode of the electrochemical cell, the necessary heating power is generated. Depending on the type of device and the power supply, the required heating power can be approximately 1 to 3 kW.The salt-containing solution, which is added to the electrochemical cell in step a) according to the cell size, provides the required conductivity at the application concentration. This conductivity is higher than the maximum conductivity of drinking water, so the individual properties of the water used are irrelevant.

[0030] For example, the electrochemical cell can be filled with water before and / or during step a). Preferably, the water is supplied to the electrochemical cell via the recirculation system if the device has one. For example, water is supplied from the water connection to the water receiving element via the supply line by opening the valve, and the recirculation pump is activated to pump the predetermined quantity of water into the electrochemical cell. Preferably, the inlet and outlet of the electrochemical cell are located in the upper part of the electrochemical cell, so that a defined quantity of water remains in the electrochemical cell after the recirculation pump is switched off.

[0031] Preferably, in step c), the water is circulated by the pump so that it flows through the electrochemical cell and the water absorption element. This flow causes the water to swirl within the electrochemical cell, mixing the bleach and, if applicable, detergent with the water.

[0032] An embodiment of the invention is shown schematically in the drawings and is described in more detail below. It is shown schematically and not to scale. Fig. 1 is a sketchy sectional view of the water-bearing electrical device according to the invention; and Fig. 2 is a circuit diagram of a control unit of the device. Fig. 1 device shown.

[0033] Fig. 1 shows a sketchy sectional view of a water-bearing electrical device according to the invention. The in Fig. 1 The device shown is a washing machine with a water intake element 1, which is designed as a tub and is configured to hold water. A drum 2 for holding laundry 8 is rotatably mounted in the water intake element 1. The device also has an electrochemical cell 3 with electrodes in the form of an anode A and a cathode K, which is configured to generate a bleaching agent when it contains a salt solution and a DC voltage is applied to the anode A and the cathode K.

[0034] Furthermore, the device has a recirculation system 4 for directing water from a first area of ​​the water intake element 1 to a second area of ​​the water intake element 1. The recirculation system 4 includes a recirculation pump 9, which is configured to pump water from the first area through the electrochemical cell 3 into the second area. Additionally, water from the first area can be pumped by a drain pump 5 of the device into a drain line 6, which is connected to a wastewater drain (not shown) to remove or discharge the water from the washing machine. The recirculation pump 9 is connected to the lower area of ​​the water intake element 1 via a line 7.An inlet and an outlet of the electrochemical cell 3 are arranged in an upper part of the electrochemical cell 3, wherein the inlet is connected to the circulation pump 9 and the outlet is connected to a line 11 which is designed to supply water passed through it to the second area of ​​the water receiving element 1.

[0035] The electrochemical cell 3 is connected via a drain valve 10 to a point in the bypass system 4 that is located upstream of the drain pump 5. The device also includes a dosing unit 12, which is configured to dose a salt-containing solution and, if necessary, a detergent into the electrochemical cell 3 by means of a dosing pump 13. Furthermore, the device includes a control unit 18, which is configured to selectively apply either direct or alternating voltage to the electrochemical cell 3. The device is connected to a water connection 16 via an inlet line 14 and a valve 15. The control unit 18 is configured to automatically control the water supply from the water connection 16 to the water intake element 1.

[0036] The drain valve 10 is located between line 7 and the electrochemical cell 3. This drain valve 10 allows the electrochemical cell 3 to be rinsed. To rinse the electrochemical cell 3, the drain valve 10 is opened and the draining water is pumped away by the drain pump 5.

[0037] In operation, a laundry washing process comprises the following steps: Water is supplied from the water inlet 16 via the valve 15 and the supply line 14 into the water intake unit 1 and pumped via the circulation pump 9 into the electrochemical cell 3, so that a predetermined quantity of water is supplied to the electrochemical cell 3. Subsequently or simultaneously, a salt-containing solution and, if applicable, a detergent are dosed from the dosing unit 12 into the electrochemical cell 3 via the dosing pump. Following the preceding steps, a DC voltage is applied to the anode A and the cathode K of the electrochemical cell 3 for a predetermined period of time. This causes the chemical reaction in the form of electrolysis to take place, producing the bleaching agent, such as H₂O₂.Water from water connection 16 is then fed into the water receiving element 1 via valve 15 and supply line 14 in a further predetermined quantity. The circulation system 4 is then activated, so that the water from the first area passes through the electrochemical cell 3 into the second area. An alternating voltage is applied to the electrochemical cell 3 to heat the fluid flowing through it. The mixing of the salt solution and, if present, concentrated detergent with the water reduces the solution's conductivity, thus generating the required heating power when the alternating voltage is applied to the electrodes. A relay (not shown) in the control unit 18 switches from the direct current to the mains alternating current.

[0038] Fig. 2 shows a circuit diagram of a control unit of the in Fig. 1 The device shown. The control unit 18 has a mains connection 24 configured to supply alternating current, a relay 20 configured to switch between direct current and alternating current, and a DC output socket 22. Control electronics (not shown) of the control unit 18 are configured to evaluate how a mains plug (not shown) is inserted and, together with a rotary relay 19 of the control unit 18, ensure that a grounded neutral conductor 23 is always connected to the electrode located at the inlet and outlet of the electrochemical cell 3. In combination, the Fig. 1 und Fig. 2 This electrode is anode A.

[0039] During operation, the system is controlled and monitored by the control electronics. The mains voltage is supplied to the control electronics, which serve as the power supply. Furthermore, the control unit 18 has a protective earth 21, allowing the control electronics to determine the polarity of the supply voltage. The rotary relay 19 is controlled so that the line with low voltage to earth (N potential) is always connected to the anode A of the electrochemical cell 3. To generate the bleaching agent, a DC voltage, specifically low DC voltage, is generated from the mains voltage by means of relay 20 and applied by the control electronics to the electrodes, i.e., anode A and cathode K. For heating, the rotary relay 19 is first controlled appropriately, and then the heating is switched on by relay 20 by applying an AC voltage to anode A and cathode K. The anode potential is then fed back to the control electronics.If a critical voltage occurs at anode A relative to the earth potential of the protective conductor 23, the control electronics switch off the heating. Reference symbol list

[0040] A Anode AC mains voltage K Cathode 1 Water absorption element 2 Drum 3 Electrochemical cell 4 Circulation system 5 Drain pump 6 Drain pipe 7 Line 8 Laundry 9 Circulation pump 10 Drain valve 11 Line 12 Dosing unit 13 Dosing pump 14 Supply line 15 Valve 16 Water connection 18 Control unit 19 Rotary relay 20 Relay 21 Protective earth 22 DC out socket 23 Grounded neutral conductor 24 Mains voltage connection

Claims

1. Water-conducting electrical appliance, comprising - a water receiving element (1), - an electrochemical cell (3) having electrodes and designed to produce a bleaching agent when it contains a salt-containing solution and a direct voltage is applied to the electrodes, - a pump designed to convey fluid located in the electrochemical cell (3) out of the electrochemical cell (3) and into the water receiving element (1), and characterised by - a control unit (18) configured to alternately apply both direct and alternating voltage to the electrodes of the electrochemical cell (3), the fluid located in the electrochemical cell (3) being heated when alternating voltage is applied.

2. Appliance according to claim 1, characterised in that the control unit (18) has a relay (20) designed to switch from direct to alternating voltage and vice versa.

3. Appliance according to claim 1 or 2, characterised in that the control unit (18) has a rotary relay (19) designed to connect a grounded N conductor (23) to an electrode of the electrochemical cell (3) that is arranged at an inlet and an outlet of the electrochemical cell (3), and / or the control unit (18) has a protective ground (21) designed in such a way that a polarity of the supply voltage can be determined.

4. Appliance according to any of the preceding claims, characterised by a recirculation system (4) for conducting water from a first region of the water receiving element (1) into a second region of the water receiving element (1), the recirculation system (4) having, as the pump, a recirculation pump (9) designed to pump water out of the first region, through the electrochemical cell (3) and into the second region.

5. Appliance according to any of the preceding claims, characterised in that an inlet and an outlet of the electrochemical cell (3) are arranged in an upper part of the electrochemical cell (3), in relation to an operational set-up position of the appliance, the inlet being connected to the pump and the outlet being connected to a line (11) designed to feed, to the water receiving element (1), fluid conducted through said line.

6. Appliance according to any of the preceding claims, characterised in that the electrochemical cell (3) is connected via an outlet valve (10) to a point of a water line system of the appliance that is arranged fluidically upstream of an outlet pump (5) designed to discharge water from the appliance.

7. Appliance according to any of the preceding claims, characterised in that it can be connected to a water connection (16), and the control unit (18) is configured to automatically control a water supply from the water connection (16) into the water receiving element (1).

8. Appliance according to any of the preceding claims, characterised by a dispensing unit (12) designed to dispense the salt-containing solution into the electrochemical cell (3).

9. Method for operating a water-conducting electrical appliance comprising a water receiving element (1), an electrochemical cell (3) having electrodes and designed to produce a bleaching agent when it contains a salt-containing solution and a direct voltage is applied to the electrodes, a pump designed to convey fluid located in the electrochemical cell (3) out of the electrochemical cell (3) and into the water receiving element (1), and a control unit (18), wherein the method has the following steps: a) feeding a salt-containing solution into the electrochemical cell (3); b) following step a), applying direct voltage to the electrodes of the electrochemical cell (3) for a predetermined period of time in order to produce the bleaching agent in the electrochemical cell (3); c) following step b), applying alternating voltage to the electrodes of the electrochemical cell (3) for a predetermined period of time in order to heat fluid located in the electrochemical cell (3); and d) conveying the fluid out of the electrochemical cell (3) and into the water receiving element (1).

10. Method according to claim 9, characterised in that water continues to be introduced in a predetermined water quantity into the electrochemical cell (3).