Method for controlling cleaning device and cleaning device, in particular for carrying out method

Abstract

The invention relates to a method for controlling a cleaning device (10), comprising: a pump (18) for conveying a cleaning liquid; an electric motor (16) for driving the pump (18); at least one battery (24) for supplying power to the electric motor (16); and a control device (26) for controlling the electric motor (16). In order to cope with the risk of dry operation in a simple and operationally friendly manner, in which a transient insufficient supply of cleaning fluid to the pump (18) is allowed, the control device (26) periodically detects the actual value of the battery voltage and the actual value of the supply current of the electric motor (16), the actual value of the supply current is compared with a predetermined minimum current value which is assigned to the actual value of the battery voltage, and if the detected actual value of the supply current is lower than the minimum current value and greater than zero, the counter reading is gradually changed in the direction of a first counter threshold value, the control device (26) interrupts the supply of energy to the electric motor (16) if the counter reading reaches a first counter threshold value. The invention further relates to a cleaning device (10), in particular for carrying out the method, comprising a pump (18), an electric motor (16), at least one battery (24) and a control device (26).

Description

Technical Field

[0001] The present invention relates to a method for controlling a cleaning device, the cleaning device having: a pump for transporting a cleaning liquid; an electric motor for driving the pump; at least one battery for supplying energy to the electric motor; and a control device for controlling the electric motor.

[0002] The present invention further relates to a cleaning device, in particular for performing the above method, the cleaning device having: a pump for transporting a cleaning liquid; an electric motor for driving the pump; at least one battery for supplying energy to the electric motor; and a control device for controlling the electric motor. Background Art

[0003] With a cleaning device of the above type, a cleaning liquid (preferably water) can be pressurized and guided onto a surface to be cleaned. The cleaning liquid can be supplied to the pump of the cleaning device through a liquid delivery line (such as a suction hose or a garden hose). With the pump, the cleaning liquid can be pressurized and output through a liquid output line (such as a pressure hose). The cleaning device has an electrical control device for controlling the electric motor that drives the pump. With the control device, the energy supply to the electric motor can be established and interrupted.

[0004] When operating the cleaning device, sufficient supply of the cleaning liquid to the pump is required because otherwise dry running will occur. Dry running may lead to severe heating of the pump and increased wear.

[0005] A method for identifying dry running of a pump is known from WO 2019 / 154494 A1, wherein the control device detects the actual value of the supply voltage and the actual value of the supply current of the electric motor, and determines the actual value of the electrical power consumption of the electric motor by multiplying these values. The determined actual value of the electrical power consumption is compared with a predetermined minimum value of the power consumption. If the actual value of the electrical power consumption is lower than the predetermined minimum value of the power consumption after the expiration of a predetermined start-up interval after turning on the electric motor, the electric motor is turned off due to the risk of dry running. In this method, outside the start-up interval, once the control device has confirmed that it is lower than the predetermined minimum value of the power consumption, the electric motor is turned off. Thus, it is possible to reliably prevent the electric motor from running when the supply of the cleaning liquid to the pump is insufficient. However, the following situation may occur: during the operation of the electric motor, there is only a short-term shortage of the supply of the cleaning liquid to the pump, and this shortage does not yet cause damage to the pump. Although the pump is in an unfavorable operating state during this shortage, this unfavorable operating state may be tolerated for a certain period of time without turning off the electric motor. Therefore, it is desirable to turn off the electric motor only when the shortage of the supply of the cleaning liquid to the pump exceeds an acceptable duration. [[ID=z18]] Summary of the Invention

[0006] Accordingly, the object of the present invention is to provide a method for controlling a cleaning device, which method allows dry running to be countered in a simple and operation-friendly manner, wherein a brief shortage of cleaning liquid supply to the pump is tolerated.

[0007] According to the invention, this object is achieved in a method of the type mentioned at the beginning in such a way that the control device periodically detects the actual value of the battery voltage and the actual value of the supply current of the electric motor, and compares the actual value of the supply current with a predetermined minimum current value assigned to the actual value of the battery voltage, and if the detected actual value of the supply current is below the minimum current value and greater than zero, the counter reading is incremented in the direction of a predetermined first counter threshold, wherein if the counter reading reaches the first counter threshold, the control device interrupts the energy supply to the electric motor.

[0008] In particular, in the method according to the invention, the control device periodically detects the actual value of the supply current of the electric motor. The actual value of the supply current, i.e. the current consumption of the electric motor, is lower during dry running compared to operating the cleaning device with a regulated supply of cleaning liquid. Therefore, the control device compares the actual value of the supply current with an admissible minimum current value. The energy supply to the electric motor is effected by means of at least one battery. The admissible minimum current value depends on the state of charge of the at least one battery and thus on the actual value of the battery voltage. The admissible minimum value of the supply current is lower at a lower state of charge, i.e. at a lower battery voltage, than at a higher state of charge. Therefore, in the method according to the invention, not only the actual value of the supply current of the electric motor is periodically detected, but also the actual value of the battery voltage is periodically detected. The control device compares the actual value of the supply current with a predetermined minimum current value assigned to the actual value of the battery voltage. This allows the state of charge of the at least one battery to be taken into account when comparing the actual value of the supply current with the minimum current value.

[0009] The actual value of the supply current of the electric motor and the actual value of the battery voltage are detected regularly and the actual value of the supply current is compared with a predetermined minimum current value assigned to the actual value of the battery voltage. If the detected actual value of the supply current is less than the minimum current value but greater than zero, there is an unfavorable operating state of the pump. To take into account the duration of this unfavorable operating state, if the actual value of the supply current is below the minimum current value and greater than zero, the control device changes the counter reading in the direction of a first counter threshold. The counter reading changes step by step from its current value in the direction of the first counter threshold until the first counter threshold is reached. Only when the first counter threshold is reached does the control device interrupt the energy supply to the electric motor. The first counter threshold is selected such that the pump may heat up within the unfavorable operating state until the first counter threshold is reached, but the pump is not yet damaged. Thus, an insufficient supply of cleaning fluid to the pump does not immediately cause the electric motor to switch off, but only when this supply deficiency has persisted for a long time and thus the counter reading has reached the first counter threshold. For example, it may occur that at the start of the pumping process, cleaning fluid is first sucked from the reserve container, such that the pump is not yet fully filled with cleaning fluid, which briefly causes a drop in the actual value of the supply current, but this does not yet lead to an interruption of the energy supply to the electric motor.

[0010] To compare the detected actual value of the supply current of the electric motor with a minimum current value dependent on the charge state of at least one battery, it may be provided, for example, that in a memory section of the control device, a plurality of battery voltage values are stored in the form of a reference table, in particular in the form of a look-up table, and for each of these battery voltage values a tolerable minimum current value for the supply current of the electric motor is assigned. This minimum current value represents the minimum allowable value of the supply current of the electric motor. Based on the detected actual value of the battery voltage (which represents a measure of the current charge state of at least one battery), the control device selects from the reference table the tolerable minimum current value of the supply current for this charge state and uses this minimum current value for the comparison with the actual value of the supply current. If the actual value of the supply current is below this minimum current value and greater than zero, the pump is in an unfavorable operating state, which indicates dry running of the pump and may lead to damage to the pump if it persists for a long time.

[0011] It may occur that the detected actual value of the battery voltage lies between two battery voltage values stored in the reference table. Then it is possible to determine the associated minimum current value based on interpolation.

[0012] Alternatively, it may also be possible that the control device determines the admissible minimum current value from the detected actual value of the battery voltage by means of a calculation function stored in the memory section. Depending on the detected actual value of the battery voltage, the minimum current value assigned to this actual value is calculated by means of the stored calculation function. The control device then uses the thus determined minimum current value of the supply current for comparison with the actual value of the supply current. If the actual value of the supply current is below this minimum current value and greater than zero, the pump is in an unfavorable operating state as described above.

[0013] In an advantageous embodiment of the method according to the invention, if the detected actual value of the supply current is not below the minimum current value assigned to the actual value of the battery voltage or the detected actual value of the supply current is zero and the value taken by the counter reading lies between a first counter threshold and a predetermined second counter threshold, the control device gradually changes the counter reading in the direction of the second counter threshold. The control device recognizes the favorable operating state of the pump based on the fact that the actual value of the supply current is not below the minimum current value. In the favorable operating state, the actual value of the supply current can also be zero. In this case, no current is supplied to the electric motor, so that the pump is not driven and thus dry running does not occur. If the value taken by the counter reading lies between the first counter threshold and the second counter threshold, this counter reading can be gradually changed periodically in the direction of the second counter threshold in the favorable operating state until the second counter threshold is reached or it is confirmed that it is again below the minimum current value. If a favorable operating state is confirmed, this indicates the proper operation of the cleaning device. Therefore, the cleaning liquid is fed to the cleaning device in a proper manner. If the control device recognizes that it is again below the minimum current value, the counter reading can be gradually changed again in the direction of the first counter threshold from its current value until either it is confirmed that it has again exceeded the minimum current value and thus the counter reading is again gradually changed in the direction of the second counter threshold or the first counter threshold is reached and thus the energy supply to the electric motor is interrupted.

[0014] Advantageously, the first counter threshold is greater than the second counter threshold. In this embodiment of the method according to the invention, in the case of being below the minimum current value, i.e., in the unfavorable operating state, the counter reading is incremented step by step. If the control device confirms that it is not below the minimum current value or the actual value of the supply current is zero and thus there is a favorable operating state, the control device decrements the counter reading accordingly.

[0015] For a simple counting mode, the lower threshold of the counter is advantageously zero.

[0016] Advantageously for simple operation, at least one battery is rechargeable.

[0017] After reaching the first counter threshold, the control device interrupts the energy supply to the electric motor. In an advantageous embodiment of the method according to the invention, if the pressure of the cleaning liquid conveyed by the pump present in the liquid outlet line of the cleaning device exceeds a predetermined cut-off value, the energy supply to the electric motor is interrupted by the pressure switch independently of the counter reading, and if the pressure of the cleaning liquid present in the cleaning liquid outlet line drops below a predetermined on value, the energy supply to the electric motor is no longer interrupted by the pressure switch. This embodiment of the method according to the invention enables the operator to control the energy supply by operating a manually closable application means which is arranged at the free end of the liquid output line which is connected to the liquid outlet line of the high-pressure cleaning device. For example, a spray gun can be used as the manually closable application means. In order to output the cleaning liquid pressurized by the pump, the operator can open the application means. Subsequently, an outlet pressure of the cleaning liquid is formed within the liquid outlet line of the cleaning device. If the operator wants to interrupt the output of the pressurized cleaning liquid, the operator can close the application means. This causes the pressure of the cleaning liquid in the liquid outlet line to rise, such that the pressure exceeds the predetermined cut-off value. If the application means is opened again by the operator, the pressure of the cleaning liquid in the liquid outlet line drops, wherein the pressure is preferably below the predetermined on value, which causes the pressure switch to no longer interrupt the energy supply to the electric motor.

[0018] In an advantageous embodiment of the method according to the invention, after the energy supply to the electric motor has been interrupted due to reaching the first counter threshold, the energy supply to the electric motor can only be restored by manually operating an operating element of the cleaning device. In order to be able to continue the operation of the cleaning device after the energy supply has been interrupted due to reaching the first counter threshold, in this embodiment of the method, the operator must manually operate an operating element of the cleaning device, such as a push-button switch. Thus, the energy supply cannot be restored automatically.

[0019] For user-friendly operation, it is advantageous that the energy supply to the electric motor can only be restored by operating the operating element after a predetermined period of time has elapsed. During this period of time, the energy supply to the electric motor cannot be restored by operating the operating element. During this period of time, the pump can cool down, such that the risk of damage can be kept low.

[0020] As described above, if the counter reading reaches a predetermined first counter threshold, the control device interrupts the energy supply to the electric motor in order to avoid overheating of the pump due to dry running. Advantageously, the control device gradually changes the counter reading in the direction of a predetermined second counter threshold after reaching the predetermined first counter threshold until the second counter threshold is reached or until the actual value of the supply current is lower than a predetermined minimum current value after the energy supply to the electric motor is restored. Since the energy supply to the electric motor is interrupted due to reaching the first counter threshold and no supply current flows, this means that the actual value of the supply current is zero. As long as no supply current flows, the control device can gradually change the counter reading in the direction of the predetermined second counter threshold after reaching the first counter threshold until the second counter threshold is reached. Therefore, in this design of the method according to the invention, even when the energy supply to the electric motor is interrupted, the control device can change the counter reading in the direction of the second counter threshold. The purpose of this is to match the counter reading with the pump cooling that occurs after the energy supply is interrupted. If the energy supply to the electric motor is restored by operating the operating element before reaching the second counter threshold, the control device either continues to change the counter reading in the direction of the second counter threshold until the second counter threshold is reached, provided that the actual value of the supply current is not lower than the minimum current value; or the control device changes the counter reading from its current value in the direction of the first counter threshold again, provided that the actual value of the supply current is lower than the minimum current value again. Therefore, the change in the counter reading corresponds to the change in the temperature of the pump.

[0021] As described above, the present invention also relates to a cleaning device, in particular for performing the above method, the cleaning device having: a pump for transporting a cleaning liquid; an electric motor for driving the pump; at least one battery for supplying energy to the electric motor; and a control device for controlling the electric motor.

[0022] In order to improve the cleaning device so that it can cope with dry running in a simple and user-friendly manner, where a short-term lack of cleaning liquid supply to the pump is tolerated, according to the invention it is proposed that the control device is set up to regularly detect the actual value of the battery voltage and the actual value of the supply current, and compare the actual value of the supply current with a predetermined minimum current value assigned to the actual value of the battery voltage, and if the detected actual value of the supply current is lower than the minimum current value and greater than zero, gradually change the counter reading in the direction of a predetermined first counter threshold, where after reaching the first counter threshold, the control device can interrupt the energy supply to the electric motor.

[0023] This design of the cleaning device enables the risk of dry running to be addressed in a simple and operator-friendly manner, wherein the energy supply to the electric motor is interrupted only after a first counter threshold is reached, allowing for a short-term shortage of cleaning liquid supply to the pump. This gives the operator the possibility to resume the short-term interrupted cleaning liquid supply to the pump while the pump is still running.

[0024] Preferably, the control device has a memory section for storing battery voltage values and the minimum current values assigned to these battery voltage values. As described above, the minimum current value indicates the minimum allowable value of the supply current of the electric motor.

[0025] Advantageously, a plurality of battery voltage values can be stored in the memory section in the form of a reference table, and the minimum current values for the supply current of the electric motor are respectively assigned to these battery voltage values. Advantageously, the control device is configured to: based on the detected actual value of the battery voltage (which represents a measure of the current charge state of at least one battery), select from the reference table the minimum current value of the supply current that is still admissible for this charge state, and use this minimum current value for comparison with the actual value of the supply current. If the actual value of the supply current is lower than this minimum current value and greater than zero, the pump is in an unfavorable operating state, which indicates dry running of the pump and may cause damage to the pump if it persists for a long time.

[0026] Alternatively, it is also possible that: a calculation function for calculating the minimum current value from the detected actual value of the battery voltage is stored in the memory section. In this design of the cleaning device according to the invention, the minimum current value is calculated based on the detected actual value of the battery voltage by means of the stored calculation function. Then, the control device uses the thus obtained minimum current value of the supply current for comparison with the actual value of the supply current. If the actual value of the supply current is lower than this minimum current value and greater than zero, the pump is in the unfavorable operating state as described above.

[0027] Preferably, the control device has: a voltage detection section for detecting the actual value of the battery voltage and a current detection section for detecting the actual value of the supply current. As described above, the battery voltage depends on the charge state of at least one battery. The higher the discharge level of at least one battery, the lower the battery voltage. The minimum current value, which represents the minimum allowable value of the supply current of the electric motor, depends on the battery voltage. Compared to when the cleaning device is operating as specified, i.e., when cleaning liquid is being transported as specified, the actual value of the supply current, i.e., the current consumption of the electric motor, is lower during dry running.

[0028] Advantageously, the control device has a control section for comparing the detected actual value of the supply current with a minimum current value, wherein the actual value of the battery voltage and the actual value of the supply current detected by the voltage detection section and the current detection section, as well as the battery voltage values stored in the memory section and the minimum current values assigned to these battery voltage values, can be provided to the control section, and by means of this control section, the detected actual value of the supply current can be compared with the minimum current value corresponding to the detected actual value of the battery voltage.

[0029] Particularly advantageously, the control section is embodied as a microcontroller.

[0030] It can be provided that the memory section is integrated into the control section.

[0031] Preferably, the control device has a counter section for gradually changing the counter reading.

[0032] It can be provided that the counter section is integrated into the control section.

[0033] Advantageously, the cleaning device has: a liquid outlet line for the pressurized cleaning liquid; and a pressure switch, wherein if the pressure of the cleaning liquid present in the liquid outlet line exceeds a predetermined cut-off value, the energy supply to the electric motor can be interrupted by the pressure switch, and wherein if the pressure of the cleaning liquid present in the liquid outlet line drops below a predetermined on value, the energy supply to the electric motor can no longer be interrupted by the pressure switch. As described above, in this design, the operator can control the energy supply by operating the dispensing mechanism connected to the cleaning device via the liquid output line. If the operator closes the dispensing mechanism, the pressure of the cleaning liquid in the liquid outlet line increases. If this pressure exceeds the predetermined cut-off value, the pressure switch can thereby interrupt the energy supply. If the operator then opens the dispensing mechanism, the pressure of the cleaning liquid in the liquid outlet line drops below the predetermined on value, and the pressure switch no longer interrupts the energy supply.

[0034] In an advantageous design of the cleaning device according to the invention, the control device has a switch section electrically controllable by the control section for establishing and interrupting the energy supply to the electric motor. As described above, the control section can compare the actual value of the supply current with the minimum current value assigned to the actual value of the battery voltage. If the actual value of the supply current is below the minimum current value and greater than zero, the control section causes the counter section to gradually change the counter reading in the direction of a first counter threshold. If the counter reading reaches the first counter threshold, the control section causes the switch section to interrupt the energy supply to the electric motor.

[0035] Advantageously, the cleaning device has a control element, and after the energy supply to the electric motor is interrupted due to reaching the first counter threshold, the energy supply to the electric motor can only be restored by manually operating the control element.

[0036] Particularly advantageously, the light-emitting element is integrated into the control element. With the help of the light-emitting element, for example, it can be indicated whether the cleaning device is operating properly. However, it is also possible that the light-emitting element, especially by flashing rhythmically, indicates that the interruption of the energy supply has been triggered due to reaching the first counter threshold.

[0037] Advantageously, the cleaning device has a timing element that predetermines a time period during which the energy supply to the electric motor cannot be restored by operating the control element. In this design of the cleaning device, the energy supply to the electric motor can only be restored by operating the control element after the time period predetermined by the timing element has expired. During this time period, the pump can cool down, so that the risk of damage can be kept very low.

[0038] It can be provided that the timing element is integrated into the control element.

[0039] The control element is preferably designed as a push-button switch. Description of the Drawings

[0040] The following description of the preferred embodiments of the present invention in conjunction with the drawings is for a more detailed elaboration. Among them:

[0041] Figure 1 Shows a front view of the cleaning device and the storage container, wherein the cleaning device occupies a position connected to the storage container;

[0042] Figure 2 Shows the cleaning device and the storage container along Figure 1 A cross-sectional view taken along line 2-2 in;

[0043] Figure 3 Shows Figure 1 A schematic block diagram of the control device of the cleaning device in. Detailed Description of the Invention

[0044] In Figure 1 And Figure 2 Schematically shows a preferred embodiment of the cleaning device according to the present invention equipped with the reference numeral 10 and the storage container 12.

[0045] The cleaning device 10 can be placed into the receiving part of the storage container 12 and occupies a position connected to the storage container 12, as shown in Figure 1 And Figure 2As shown in the figure. The reservoir container 12 can hold the cleaning liquid to be pressurized, and this cleaning liquid can be conveyed to the cleaning device 10. This is particularly advantageous when the cleaning liquid cannot be conveyed from the outside. However, it is also possible to separate the cleaning device 10 from the reservoir container 12 and convey the cleaning liquid to the cleaning device 10 from the outside, for example via a suction hose or a garden hose.

[0046] The cleaning device 10 has a housing 14 in which an electric motor 16 and a pump 18 are arranged. The pump 18 is in fluid connection with the device inlet 20 of the cleaning device 10, and through this device inlet, the cleaning liquid to be pressurized can be conveyed to the cleaning device 10. In order to supply the cleaning device 10 with cleaning liquid, the device inlet 20 can be detachably connected to a liquid conveying line 21 that sinks into the reservoir container 12. The pump 18 pressurizes the cleaning liquid. The pressurized cleaning liquid can be output via the device outlet 22 of the cleaning device 10 that is in fluid connection with the pump 18. A liquid output line, such as a pressure hose, which is known per se and not shown in the drawings for a clearer overview, can be coupled to the device outlet 22. The pressure hose can have a discharging mechanism for the cleaning liquid, such as a spray gun, at its free end that can be manually closed by the operator.

[0047] The energy supply to the cleaning device 10, especially the electric motor 16, is carried out by a battery 24 arranged on the housing 14, which is advantageously rechargeable. Regarding the upright use position of the cleaning device 10 shown in Figure 1 and Figure 2 the battery 24 is arranged on the upper side of the cleaning device.

[0048] In addition to the electric motor 16 and the pump 18, a control device 26 is also arranged in the housing 12. With the aid of the control device 26, the energy supply to the electric motor 16 can be established and interrupted. A schematic block diagram of the control device 26 is shown in Figure 3 the figure.

[0049] The energy supply to the electric motor 16 can also be established and interrupted with the aid of a pressure switch 30. The pressure switch 30 is assigned to a liquid outlet line 32 arranged upstream of the device outlet 22. This allows the energy supply to the electric motor 16 to be established and interrupted depending on the pressure of the cleaning liquid present in the liquid outlet line 32. If the discharging mechanism arranged at the free end of the pressure hose is closed by the operator, the pressure of the cleaning liquid rises in the region of the liquid outlet line 32. If this pressure rise exceeds a predetermined cut-off value, the energy supply to the electric motor 16 is interrupted by the pressure switch 30. If the operator opens the discharging mechanism again, the pressure of the cleaning liquid in the liquid outlet line 32 drops below a predetermined on value and the pressure switch 30 resumes the energy supply to the electric motor 16.

[0050] As can be seen fromFigure 3 It can be clearly seen that the control device 26 has a voltage detection section 34 and a current detection section 36. With the help of the voltage detection section 34, the battery voltage provided by the battery 24 is detected regularly. With the help of the current detection section 36, the supply current of the electric motor 16 is detected regularly.

[0051] The control device 26 also has a memory section 38, in which a plurality of battery voltage values are stored in the form of a reference table, in particular in the form of a look-up table, and to each of these battery voltage values there is assigned a minimum current value that is still admissible for the supply current of the electric motor 16. This minimum current value represents the minimum allowable value of the supply current of the electric motor 16. The actual value of the detected battery voltage represents a measure of the current charge state of the battery 24. The higher the degree of discharge of the battery 24, the lower the battery voltage provided. The minimum current value, i.e., the minimum allowable current value below which dry running is indicated, depends on the battery voltage. The minimum current value that is still admissible is lower in a lower charge state than in a higher charge state.

[0052] Alternatively, it is also possible that a calculation function for calculating the minimum current value based on the actual value of the detected battery voltage is stored in the memory section 38.

[0053] The control device 26 has a control section 40. The memory section 38 is preferably integrated into the control section 40 and provides the data stored in this memory section to the control section 40.

[0054] The actual value of the battery voltage is transmitted by the voltage detection section 34 to the control section 40, and the actual value of the supply current is transmitted by the current detection section 36 to the control section 40.

[0055] With the help of the control section 40, the control device 26 can recognize whether the actual value of the supply current is below the minimum current value. For this purpose, the control section 40 selects, based on the actual value of the detected battery voltage, the minimum current value that is still admissible for the supply current for this charge state from the reference table stored in the memory section 38, and compares the actual value of the detected supply current with the minimum current value selected from this reference table. If the actual value of the supply current is below this minimum current value and greater than zero, the pump 18 is in an unfavorable operating state, which indicates dry running of the pump 18 and may cause damage to the pump 18 if it lasts for a long time. If the actual value of the supply current is not below this minimum current value or is equal to zero, the pump 18 is in a favorable operating state, in which the cleaning liquid is supplied to the pump 18 as required.

[0056] As described above, alternatively, calculation functions can also be stored in the memory section 38. Based on the actual value of the detected battery voltage, the minimum current value can be calculated by means of the stored calculation functions. Subsequently, the control device 26 can use the thus obtained minimum current value of the supply current to compare with the actual value of the supply current. If the actual value of the supply current is lower than this minimum current value and greater than zero, the pump is in an unfavorable operating state as described above.

[0057] The control device 26 also has a counter section 42. The counter section 42 is preferably integrated into the control section 40, and the control section 40 can cause this counter section to change the counter reading.

[0058] If the control section 40 confirms that it is lower than the minimum current value, where this minimum current value is greater than zero, then this control section causes the counter section 42 to gradually change the counter reading in the direction of a predetermined first counter threshold. The counter reading can be changed regularly starting from its current value until the predetermined first counter threshold is reached. If the first counter threshold is reached, the control section 40 causes the power control switch section 44 of the control device 26 to interrupt the energy supply to the electric motor 16 in order to thereby counter the risk of dry running of the pump 18.

[0059] If the control section 40 confirms that the detected actual value of the supply current is not lower than the minimum current value or is zero and the counter reading is between the first counter threshold and a predetermined second counter threshold, then the control section 40 causes the counter section 42 to gradually change the counter reading in the direction of the second counter threshold. The counter reading is continuously changed in the direction of the second counter threshold until the second counter threshold is reached or until the control section 40 again confirms that it is lower than the minimum current value. For the case where the actual value of the supply current is again lower than the minimum current value, the control section 40 causes the counter section 42 to gradually change again in the direction of the first counter threshold starting from its current value.

[0060] The first counter threshold is selected such that although the pump 18 may heat up in the unfavorable operating state, the pump 18 is not yet damaged.

[0061] In the shown preferred embodiment, the first counter threshold is greater than the second counter threshold, such that when it is lower than the minimum current value, the counter section 42 increments the counter reading in the direction of the first counter threshold. If the actual value of the supply current is not lower than the minimum current value or is zero, the counter section 42 decrements the counter reading in the direction of the second counter threshold.

[0062] Preferably, the lower counter threshold is zero.

[0063] To switch on the electric motor 16, the cleaning device 10 has an operating element in the form of a pushbutton switch 46 which can be actuated by the user and which is conductively connected to the control device 26.

[0064] If the energy supply to the electric motor 16 has been interrupted by the switching element 44 due to a first counter threshold being reached, the control element 40 causes the counter element 42 to incrementally change the counter reading continuously in the direction of a second counter threshold until the second counter threshold is reached. The purpose of this is to match the counter reading to the cooling of the pump 18 which occurs after the energy supply has been interrupted.

[0065] If the first counter threshold is reached, the control device 26 interrupts the energy supply to the electric motor 16. This prevents damage to the pump 18 due to insufficient delivery of the cleaning liquid.

[0066] If the energy supply to the electric motor 16 is interrupted after the first counter threshold has been reached, the energy supply can only be restored by the operator actuating the pushbutton switch 46. However, if the energy supply to the electric motor 16 is interrupted due to the closure of the dispensing mechanism arranged at the free end of the pressure hose, the energy supply can be restored at any time by reopening the dispensing mechanism without additionally actuating the pushbutton switch 46.

[0067] The light-emitting element 50 is integrated into the pushbutton switch 46. By means of the light-emitting element 50, it is possible, for example, to indicate whether the cleaning device 10 is operating correctly. The light-emitting element 50 can, for example, emit light continuously. However, the light-emitting element 50 can also indicate, for example, by rhythmic flashing that the control element 40 has caused the switching element 44 to interrupt the current supply due to the first counter threshold having been reached.

[0068] The control device 26 also has a timing element 52. The timing element 52 is preferably integrated into the control element 40.

[0069] The timing element 52 prescribes the period of time which must elapse after the energy supply to the electric motor 16 has been interrupted during which the energy supply to the electric motor 16 cannot be restored by manual actuation of the pushbutton switch 46. This is used to enable the pump 18 to cool for a predetermined period of time before the energy supply is re-established.

[0070] To operate the cleaning device 10, the operator can first fill the reserve container 12 with a cleaning liquid, such as water, and establish the energy supply to the electric motor 16 by actuating the pushbutton switch 46. To clean a surface or an article in particular, the cleaning liquid is conveyed from the reserve container 12 via the liquid delivery line 21 through the device inlet 20 of the pump 18. The pump 18 pressurizes the cleaning liquid. The cleaning liquid can be output to the surface to be cleaned or the article to be cleaned via the device outlet 22, the pressure hose connected to the device outlet, and the liquid output mechanism. Cleaning can be carried out continuously as long as there is cleaning liquid in the reserve container 12. In the case of a need to continue cleaning, the reserve container 12 can be refilled with the cleaning liquid. If the cleaning liquid in the reserve container 12 is insufficient, the actual value of the supply current detected by the current detection section 36 decreases because the pump 18 is no longer adequately supplied with the cleaning liquid. Therefore, the control section 40 of the control device 26 recognizes that the minimum current value is below the actual value of the battery voltage but greater than zero, and dry running is about to occur. Then, the control section 40 causes the counter section 42 to gradually change the counter reading in the direction of the first counter threshold. As long as the minimum current value is continuously below, the counter reading is periodically changed in the direction of the first counter threshold until the first counter threshold is reached. Here, the first counter threshold is preset such that the pump may heat up until the first counter threshold is reached but is not yet damaged. If the first counter threshold is reached, the control section 40 causes the switch section 44 to interrupt the energy supply to the electric motor 16. Then, the counter reading is periodically changed in the direction of the second counter threshold until the second counter threshold is reached. However, the operator can also restore the energy supply to the electric motor 16 by actuating the pushbutton switch 46 before the second counter threshold is reached. However, this can only be achieved after the expiration of the time period preset by the timing section 52. In this case, as long as the control section 40 does not confirm that the minimum current value is below, the counter reading continues to change in the direction of the second counter threshold from its current value. If the control section 40 confirms that the minimum current value is below again, the counter reading changes in the direction of the first counter threshold from its current value.

Claims

1. A method for controlling a cleaning device (10), the cleaning device having: a pump (18) for transporting a cleaning liquid; an electric motor (16) for driving the pump (18); at least one battery (24) for supplying energy to the electric motor (16); and a control device (26) for controlling the electric motor (16), characterized in that, The control device (26) periodically detects the actual value of the battery voltage and the actual value of the supply current of the electric motor (16), and compares the actual value of the supply current with a predetermined minimum current value assigned to the actual value of the battery voltage. If the detected actual value of the supply current is lower than the minimum current value and greater than zero, the counter reading is incremented in the direction of a predetermined first counter threshold. If the counter reading reaches the first counter threshold, the control device (26) interrupts the energy supply to the electric motor (16).

2. The method according to claim 1, characterized in that, If the detected actual value of the supply current is not lower than the minimum current value assigned to the actual value of the battery voltage or the detected actual value of the supply current is zero, and the value taken by the counter reading lies between the first counter threshold and a predetermined second counter threshold, the control device (26) increments the counter reading in the direction of the second counter threshold.

3. The method according to claim 2, wherein The first counter threshold is greater than the second counter threshold.

4. The method according to any one of the preceding claims, characterized in that The at least one battery (24) is rechargeable.

5. The method according to any one of the above claims, characterized in that, If the pressure of the cleaning liquid conveyed by the pump (18) in the liquid outlet line (32) of the cleaning device (10) exceeds a predetermined cut-off value, the energy supply to the electric motor (16) is interrupted by the pressure switch (30). If the pressure of the cleaning liquid in the cleaning liquid outlet line (32) drops below a predetermined on value, the energy supply to the electric motor (16) is no longer interrupted by the pressure switch (30).

6. The method according to any one of the preceding claims, characterized in that, After the energy supply to the electric motor (16) is interrupted due to reaching the first counter threshold, the energy supply to the electric motor can only be restored by manually operating the operating element (46) of the cleaning device (10).

7. The method according to claim 6, wherein Only after a predetermined time period has elapsed can the energy supply to the electric motor (16) be restored by operating the operating element (46).

8. The method according to any one of the preceding claims, characterized in that, After the counter reading reaches the predetermined first counter threshold, the control device (26) changes the counter reading in the direction of the second counter threshold until the second counter threshold is reached or until the actual value of the supply current is lower than the predetermined minimum current value after the energy supply to the electric motor (16) is restored.

9. A cleaning device, in particular for carrying out the method according to any one of the preceding claims, the cleaning device having: a pump (18) for conveying a cleaning liquid; an electric motor (16) for driving the pump (18); at least one battery (24) for supplying energy to the electric motor (16); and a control device (26) for controlling the electric motor (16), characterized in that, The control device (26) is configured to: periodically detect the actual value of the battery voltage and the actual value of the supply current, and compare the actual value of the supply current with a predetermined minimum current value assigned to the actual value of the battery voltage. If the detected actual value of the supply current is lower than the minimum current value and greater than zero, the counter reading is incremented in the direction of the first counter threshold. After reaching the predetermined first counter threshold, the energy supply to the electric motor (16) can be interrupted by the control device (26).

10. The cleaning device according to claim 9, wherein, The control device (26) has a memory element (38) for storing the battery voltage values and the minimum current values assigned to these battery voltage values.

11. The cleaning device according to claim 10, characterized in that, In the memory section (38), a plurality of battery voltage values can be stored in the form of a reference table, and minimum current values for the supply current to the electric motor are respectively assigned to these battery voltage values.

12. The cleaning device according to claim 9, characterized in that, The control device (26) has a memory section (38), wherein a calculation function for calculating the minimum current value from the actual value of the detected battery voltage can be stored in the memory section (38).

13. The cleaning device according to any one of claims 9 to 12, characterized in that, The control device (26) has a voltage detection section (34) for detecting the actual value of the battery voltage and a current detection section (36) for detecting the actual value of the supply current.

14. The cleaning device according to claim 10 in combination with claim 13, characterized in that, The control device (26) has a control section (40), wherein the actual value of the battery voltage and the actual value of the supply current detected by the voltage detection section (34) and the current detection section (36), as well as the battery voltage values stored in the memory section (38) and the minimum current values assigned to the battery voltage values, can be provided to the control section (40), and the actual value of the detected supply current can be compared with the minimum current value assigned to the actual value of the detected battery voltage value by means of the control section (40).

15. The cleaning device according to any one of claims 9 to 14, characterized in that, The control device (26) has a counter section (42) to gradually change the counter reading.

16. The cleaning device according to any one of claims 9 to 15, characterized in that, The cleaning device (20) has: a liquid outlet line (32) for the pressurized cleaning liquid; and a pressure switch (30), wherein if the pressure of the cleaning liquid present in the liquid outlet line (32) exceeds a predetermined cut-off value, the energy supply to the electric motor (16) can be interrupted by the pressure switch (30), and wherein if the pressure of the cleaning liquid present in the liquid outlet line (32) drops below a predetermined on value, the energy supply to the electric motor (16) can no longer be interrupted by the pressure switch (30).

17. The cleaning device according to any one of claims 14 to 16, characterized in that, The control device (26) has a switch section (44) that can be electrically controlled by the control section (26) to establish and interrupt the energy supply to the electric motor (16).

18. The cleaning device according to any one of claims 9 to 17, characterized in that, The cleaning device (10) has an operating element (46), and after the energy supply to the electric motor (16) is interrupted due to reaching the first counter threshold, the energy supply to the electric motor can only be restored by manually operating the operating element (46).

19. The cleaning device according to claim 18, characterized in that, The cleaning device (10) has a timing section (52), and the timing section predetermines a time period during which the energy supply to the electric motor (16) cannot be restored by operating the operating element (46).

20. The cleaning device according to claim 18 or 19, characterized in that, The operating element is designed as a push-button switch (46).

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