DE102017201008B3 - Laundry care device with a controller - Google Patents

Abstract

The present invention relates to a laundry care apparatus (100) with a washing tub (105) for receiving washing liquid, wherein the tub (105) has a discharge opening (111), wherein the discharge opening (111) is fluidly connected to a conduit (115) in the conduit (115), a variable speed pump (117) for pumping washing liquid from the tub (105) and through the conduit (115) is arranged, and a controller (119) for controlling the variable speed pump (117). The controller (119) is configured to activate the variable speed pump (117) and operate at a nominal pumping speed (141) for a first time period (147) to deliver wash fluid having a nominal volume flow (143) from the tub (105) and through Drain pipe (115). The controller (119) is configured to reduce the nominal pumping speed (141) of the variable speed pump (117) to a minimum pumping speed (155) during a second period of time (149) subsequent to the first period of time (147) when the volume flow rate of the Variable speed pump (117) pumped washing liquid falls below a volume flow minimum threshold (157). The controller (119) is configured to increase the minimum pumping speed (155) of the variable speed pump (117) to a maximum pumping speed (159) during a third period (151) subsequent to the second period (149) when the volume flow is increased by the third variable pump (117) pumped fluid reaches the volume flow minimum threshold (157), wherein the maximum pump speed (159) is greater than the minimum pump speed (155) and the nominal pump speed (141) to provide a stationary air swirl at a pump suction port of the variable speed pump (117) and biphasic To remove dissolved air in a pump pressure chamber of the variable speed pump (117). The controller (119) is configured to reduce the maximum pumping speed (159) of the variable speed pump (117) to the nominal pumping speed (141) during a fourth period (153) subsequent to the third period (151) when the volume flow through the variable speed pump (117) pumped wash fluid the nominal volume flow

Description

The present invention relates to a laundry care device with a controller.

In a laundry care device, washing liquid is pumped out of a tub of the laundry care device by a pump. When the level of the washing liquid in the tub sinks below a certain level, the pump sucks in air, whereby the pump is vented suction chamber and pressure chamber side. In order for a ventilated pump to be able to build up a volume flow of pumped washing liquid again, the ventilated pump must displace air on the suction side and on the pressure side. Since a vortex induced by the impeller rotation of the pump forms in the suction-side Pumpenanströmung the pump, which can prevent the re-flow of the pump, this can lead to a backflow of washing liquid in the tub. By back-stagnant washing liquid in the tub, a rotation of the laundry drum in the laundry care device may be limited because the laundry drum then rotates with higher drive torque in the washing liquid Rückstaumenge and this Rückstaumenge is then also set in rotation in the tub.

In the EP 2 428 608 A1 discloses a method of operating a pump of a washing machine, wherein the delivery rate, pump speed and pump rotation direction of the pump can be varied depending on the detected level of the washing liquid and its density in a treatment tank.

In DE 38 25 500 A1 discloses a further method for operating a pump of a washing machine, wherein the delivery rate of the pump is adapted to the accumulating wastewater in dependence on a nominal-actual value comparison of the current consumption of the pump. The adaptation is provided by an intermittent operation of the pump.

A washing machine controller for operating a pump is disclosed DE 11 2006 002 944 T5 in which, depending on one or more sensed parameters, the speed of the pump is controlled so as to discharge water at a predetermined delivery rate from a water tank.

DE 10 2014 105 527 B3 discloses a method of controlling a flooding pump system which includes a pump having measurable properties for circulating wash liquor at an adjustable volumetric flow rate into a treatment tank of a washing machine. In the method according to DE 10 2014 105 527 B3 At least operating parameters of the pump comprising a first period of time and a volume flow during the first time period are provided and the pump is operated with these parameters. The pump is a variable speed flooding pump that operates with two different flow rates. Furthermore, a slurping of the pump is monitored and in the case of a detected slurping the operating parameter time period and / or volume flow is adjusted so that a time-averaged volume flow is reduced.

It is the object underlying the invention to provide a laundry care device, in which an effective pumping out of washing liquid from a tub of the laundry care device is ensured.

This object is solved by the objects with the features according to the independent claims. Advantageous embodiments are the subject of the dependent claims, the description and the drawings.

According to a first aspect, the object according to the invention is provided by a laundry care appliance having a suds container for holding washing liquid, wherein the suds container has a discharge opening, wherein the discharge opening is fluidly connected to a line, wherein a variable-speed pump for pumping washing liquid out of the suds container and disposed through the conduit, and a controller for controlling the variable speed pump, wherein the controller is configured to activate the variable speed pump and operate at a nominal pump speed during a first period of time to deliver wash fluid having a nominal volume flow from the tub and through the tub Drain line, wherein the controller is adapted to reduce the Nominalpumpdrehzahl the variable-speed pump to a Mindestpumpdrehzahl during a subsequent to the first time period, the second time period, when the V the controller is configured to increase the Mindestpumpdrehzahl the variable speed pump to a maximum pumping speed, when the volume flow of the pumped by the variable speed pump the washing liquid during a second period subsequent to the third time period Volume limit minimum threshold reached, wherein the maximum pump speed is greater than the minimum pump speed and the nominal pump speed to a standing air turbulence at a Pumpenensaugmund the variable-speed pump and two-phase dissolved air in a To remove the pump pressure chamber of the variable speed pump, and wherein the controller is adapted to reduce the maximum pump speed of the variable speed pump to the nominal pumping speed during a fourth period subsequent to the third period when the volume flow of the pumped liquid pumped by the variable speed pump reaches the nominal volume flow Wash the washing liquid again with the nominal volume flow effectively out of the tub and through the line.

This achieves the technical advantage that by reducing the nominal pump speed of the variable speed pump to the minimum pump speed and then increasing the minimum pump speed to the maximum pump speed, a stagnant air vortex present in the variable speed pump can be effectively removed. Thus, the air vortex falls when pumping the washing liquid with the low minimum pump speed together and is then displaced on the pressure side at the high maximum pumping speed. As a result, a drop in the volume flow of the pumped through the pump washing liquid occurring after a suction of air can be compensated relatively quickly again and pump out the pump again with no significant delay time washing liquid with the nominal volume flow.

In conventional laundry care equipment, when the level of washing liquid in the tub decreases, the pump may draw in air, resulting in a break in the volume flow of the washing liquid pumped by the pump. The vented pump must displace the air from the pump on both the suction side and the pressure side for a renewed volume flow build-up so that the nominal volume flow can be restored. This Luftverdrängungsprozess and thus the re-forming of the nominal volume flow can often adjust only delayed, because formed on the pump suction in the suction, central and axial Pumpenlaufradanströmung within the pump induced by the impeller rotation, standing circulation vortex, which has low core pressures due to the high peripheral speeds and so that the air dissolved in the flow centered around the swirl center axis. As a result, the standing vortex collects the air on the suction side and thus blocks the fresh flow of the washing liquid at the suction mouth of the pump. A suction-side damming the freewheeled scrubbing liquid is the result, so that the Waschflüssigkeitsrückstaumenge generated scrubbing liquid levels in the tub in which the rotating laundry drum can dip into the washing liquid, thereby increasing the engine torque of a drum drive excessively, so that the spin process may need to be canceled.

In the laundry care apparatus according to the present disclosure, the controller detects the presence of air swirl in the pump by decreasing the volumetric flow below a minimum volume flow threshold. The controller responds to the drop in volume flow by reducing the nominal pump speed of the pump to the minimum pump speed and by subsequently increasing the minimum pump speed to the maximum pump speed. As a result, it can be achieved that the suction-induced induced air vortex collapses before the impeller in the pump, the air is sucked into the pressure chamber of the pump and the air is then pumped out of the pump and through the line with a faster increasing volume flow of the pumped washing liquid. Also, the two-phase mixture in the pump pressure chamber, in which the different phase components are homogeneously distributed and thus not yet present as two separate phases as at the pump suction, can be initially pumped out by the abrupt speed change. As a result, the nominal volume flow sets in again relatively quickly and the pump can be operated again with the nominal pumping speed lowered again.

Due to the rapid removal of the vortex of air from the pump, a significant decline in the volume flow of the pumped washing liquid and thereby caused backflow of washing liquid can be prevented in the tub.

Thereby, it can be prevented that the rotary laundry drum dips into the back-flowed washing liquid in the tub, which foams the washing liquid, thereby making it difficult to pump out the washing liquid from the tub and increases the drum driving torque, which not only reduces the life of the drum motor, but the whole Device load, such as Bearings, springs, dampers, or the entire vibration system, reinforced.

Advantageously, the controller can determine the operating state of the pump by the electrical power requirement of the variable-speed pump, in particular by the torque-forming current. As a result, the controller can determine, for example, a drop in the volume flow of the washing liquid delivered by the pump in that the torque-forming current applied to the pump drops.

Under a laundry care device is understood a device that is used for laundry care, such as a washing machine or a Dryer. In particular, such a laundry care appliance is understood as a household laundry care appliance. So a laundry care device, which is used in the context of household management, and is treated with the laundry in normal household quantities.

In an advantageous embodiment of the laundry care apparatus, after the end of the second period, the controller is configured to increase the minimum pump speed of the variable speed pump to the maximum pump speed without time delay at the beginning of the third period, or if the controller is configured to set the minimum pump speed after the end of the second period the variable-speed pump after an interval time interval during the third period to increase the maximum pumping speed, wherein the intermediate time interval is in particular between 1 second and 5 seconds.

As a result, the technical advantage is achieved that a particularly effective removal of the air vortex is ensured from the variable-speed pump. If the minimum pump speed without time delay is immediately increased to the maximum pump speed, the air vortex can be removed from the pump very quickly right at the beginning of the third time period, whereby the nominal volume flow quickly returns. If an interim time interval elapses after the second time interval, it can be ensured that the air swirl within the pump has completely collapsed and the air can then be completely removed from the pump as the minimum pump speed is increased to the maximum pump speed. The intermediate time interval may in particular be between 1 second and 5 seconds or may be longer if the suction side has not yet accumulated a sufficient amount of alkaline suppression that is sufficient for the volume flow to reach the volume flow minimum threshold value.

In a further advantageous embodiment of the laundry care appliance, the laundry care appliance comprises a program selection device for selecting a laundry care program and / or a weight detection device for detecting a weight of laundry in a laundry drum of the laundry care device, wherein the controller is designed to determine the duration of the interim time interval depending on the selected laundry care program and Determine the speed profile of the variable speed pump depending on the selected laundry care program and / or the detected weight of the laundry.

As a result, the technical advantage is achieved that a particularly effective removal of the air vortex can be ensured from the pump. Since the weight of the laundry, or the type of laundry selected by a laundry care program, has a significant effect on the amount of wash liquid retained by the laundry, the controller may advantageously adjust the duration of the interim interval and / or the speed profile of the variable speed pump to the amount pumped Adjust washing liquid.

In a further advantageous embodiment of the laundry care appliance, the variable-speed pump comprises an electric motor, in particular a permanent-magnet brushless synchronous drive.

As a result, the technical advantage is achieved that a particularly effective, variable-speed pump operation can be ensured by the electric motor, in particular a permanent-magnet brushless synchronous drive.

In a further advantageous embodiment of the laundry care appliance, the laundry care appliance has a power detection element for detecting an electric power value of the variable speed pump, wherein the controller is configured to reduce the nominal pumping speed of the variable speed pump to the minimum pumping speed during the second time period when the detected electric power value has a minimum reference power value falls below, wherein the minimum reference power value corresponds to an electric power value of the variable-speed pump when pumping washing liquid with the volume flow minimum threshold.

As a result, the technical advantage is achieved that the controller recognizes a drop in the volume flow of the pumped through the pump washing liquid in that the electrical power value of the pump also drops. By means of a correlation between the volumetric flow and the electrical power value stored in the control, the control can determine that the volumetric flow of the conveyed scrubbing liquid falls below the volumetric flow minimum threshold when the minimum reference power value falls below the volumetric flow value, whereby the occurrence of an air swirl in the pump can be detected ,

In a further advantageous embodiment of the laundry care appliance, the controller is designed to increase the minimum pumping speed of the variable speed pump to the maximum pumping speed during the third time period when the detected electric power value reaches the minimum reference power value.

This achieves the technical advantage that the controller recognizes a renewed increase in the volume flow to the volume flow minimum threshold value of the washing liquid conveyed by the pump because the detected electrical power value correlated with the volume flow again reaches the minimum reference power value during the third time interval.

In a further advantageous embodiment of the laundry care device, the controller is configured to reduce the maximum pumping speed of the variable speed pump to the nominal pumping speed during the fourth time period when the detected electric power value reaches a nominal reference power value, wherein the nominal reference power value corresponds to an electrical power value of the variable speed pump when pumping out washing fluid corresponds to the nominal volume flow.

As a result, the technical advantage is achieved that the controller recognizes a change in the volume flow of the pumped through the pump washing liquid in that the electric power value of the pump also changes. By means of a correlation between the volume flow and the electrical power value stored in the controller, the control can recognize, when the nominal reference power value has been reached or exceeded by the detected electrical power value, that the volume flow of the pumped washing fluid has reached or exceeds the nominal volume flow, as a result of which the removal of a Air vortex in the pump can be detected. Furthermore, it can thus be recognized whether there is again a backpressure amount of washing liquid on the suction side, which pumps the pump only to a great extent due to the presence of the stationary air vortex in the impeller flow of the impeller.

In a further advantageous embodiment of the laundry care appliance, the power detection element comprises a power sensor for detecting an electric power of the variable-speed pump and / or a current sensor for detecting a supply current of the variable-speed pump.

Thereby, the technical advantage is achieved that can be effectively detected by the power sensor and / or current sensor for detecting a supply current of the pump as soon as the pump sucks an air-washing liquid mixture.

In a further advantageous embodiment of the laundry care appliance, the laundry care appliance has a flow sensor for detecting a flow rate of the washing liquid pumped out by the variable speed pump, wherein the controller is designed to reduce the nominal pumping speed of the variable speed pump to the minimum pumping speed during the second time period if the detected flow rate is less than a reference flow velocity value, and wherein the controller is configured to increase the minimum pumping rotational speed to the maximum pumping rotational speed during the third time period when the detected flow velocity reaches the reference flow velocity value, the reference flow velocity value corresponding to a flow velocity value of the washing liquid when pumping out washing liquid having the volume flow minimum threshold.

As a result, the technical advantage is achieved that the controller recognizes a change in the volume flow of the pumped through the washing liquid by the fact that the flow rate of the pumped through the pump washing liquid also changes.

In a further advantageous embodiment of the laundry care appliance, the laundry care appliance has a fill level sensor for detecting a fill level of wash liquor in the tub, the controller is designed to reduce the nominal pump speed to the minimum pump speed during the second time period when the detected fill level falls below a minimum fill level, and is the controller is configured to increase the minimum pump speed to the maximum pump speed during the third time period when the detected level reaches the minimum level again.

As a result, the technical advantage is achieved that it is ensured that, in addition to the volume flow of the pumped by the variable-speed pump washing liquid also the level of the washing liquid in the tub can be used as another redundancy parameter by the controller to an effective removal of the air vortex to ensure the pump.

In a further advantageous embodiment of the laundry care device, the laundry care device has an inlet nozzle for introducing washing liquid into the tub, wherein the drain opening of the tub is fluidly connected to the inlet nozzle through the conduit, and wherein the variable speed pump is formed, washing liquid through the discharge opening of the Leach tank in the line and pump out the pumped washing liquid through the line and through the inlet nozzle to pump back into the tub.

Thereby, the technical advantage is achieved that the removal of the air vortex in the pump can be carried out effectively in a pumping system for pumping back washing liquid from the tub and re-feeding the washing liquid into the tub. This results in the pumping system a rapid pump restart after a demolished volume flow of funded washing liquid.

In a further advantageous embodiment of the laundry care device, the controller is designed to control the variable-speed pump during the first, second, third and fourth time periods during a spin process carried out by the laundry care device.

Thereby, the technical advantage is achieved that an effective removal of the air vortex from the pump during a spin process when the pump is in a ventilated state, is ensured.

According to a second aspect, the object of the invention is achieved by a method for pumping washing liquid from a tub of a laundry care device, wherein the laundry care device has a tub for receiving washing liquid, wherein the tub has a drain opening, wherein the drain opening is fluidly connected to a conduit, wherein a variable speed pump for pumping wash liquid from the tub and through the conduit is disposed in the conduit, and has a controller for controlling the variable speed pump, the method comprising the following steps; Activating the variable speed pump and operating the variable speed pump at a nominal pump speed by the controller during a first time period to pump wash fluid of nominal volume flow out of the tub and through the conduit; Reducing the nominal pump speed of the variable speed pump to a minimum pump speed by the controller during a second period subsequent to the first time period when the volume flow of the wash pumped by the variable speed pump falls below a minimum volumetric flow threshold, increasing the minimum pump speed to the maximum pump speed during the control the second time period subsequent third time period when the volume flow of the pumped by the variable-speed pump washing liquid reaches the volume flow minimum threshold, wherein the maximum pumping speed is greater than the Mindestpumpdrehzahl and the nominal pumping speed to a standing air turbulence at a Pumpenensaugmund the variable-speed pump and two-phase dissolved air in a pump pressure chamber To remove the variable speed pump, and reducing the maximum pump speed of the variable speed pump on the Nominal pumping speed by the controller during a fourth period of time subsequent to the third period when the volume flow of the washing fluid pumped by the variable speed pump reaches the nominal volumetric flow rate to effectively purge the washing liquid from the tub and line again at the nominal volumetric flow rate.

Thereby, the technical advantage is achieved that can be ensured by the method effective removal of an induced, standing air vortex in front of the pump impeller from the variable-speed pump.

In an advantageous embodiment of the method, the laundry care device has a power detection element for detecting an electric power value of the variable speed pump, and the method comprises the following steps, reducing the nominal pumping speed of the variable speed pump to the minimum pump speed by the controller during the second time period, if the detected electric power value falls below a minimum reference power value, wherein the minimum reference power value corresponds to an electric power value of the variable speed pump when pumping wash fluid with the volume flow minimum threshold, increasing the minimum pump speed to the maximum pump speed by the controller during the third time period when the detected electric power value reaches the minimum reference power value, reducing the maximum pump speed to the nominal pump speed by the controller during the fourth time delay nitts, when the detected electric power value reaches a nominal reference power value, wherein the nominal reference power value corresponds to an electric power value of the variable-speed pump when pumping washing liquid with the nominal volume flow.

Thereby, the technical advantage is achieved that by detecting an electric power value of the variable-speed pump, the volume flow of the pumped through the pump washing liquid can be determined particularly advantageous, whereby an effective removal of air swirls can be ensured from the pump.

In an advantageous embodiment of the method, increasing the minimum pump speed to the maximum pump speed without time delay after reducing the Nominal pump speed to the minimum pump speed performed, or the method comprises an intermediate time interval between reducing the nominal pump speed to the minimum pump speed and increasing the minimum pump speed to the maximum pump speed, the intermediate time interval is in particular between 1 second and 5 seconds.

Thereby, the technical advantage is achieved that an immediate increase of the minimum pump speed to the maximum pump speed allows rapid pumping, whereas an intermediate time interval ensures that a sufficient amount of washing liquid is available for pumping. The intermediate time interval may in particular be between 1 second and 5 seconds or may be longer if the suction side has not yet accumulated a sufficient quantity of alkaline recovery sufficient for the volume flow to reach the volume flow minimum threshold value.

Embodiments of the invention are illustrated in the drawings and will be described in more detail below.

• 1 eine schematische Ansicht eines Wäschepflegegeräts;
• 2 eine schematische Ansicht eines Umpumpsystems eines Wäschepflegegeräts mit einer drehzahlvariablen Pumpe;
• 3 eine graphische Darstellung eines herkömmlichen Pumpvorgangs in einem Wäschepflegegerät;
• 4 eine graphische Darstellung eines Pumpvorgangs in einem Wäschepflegegerät nach einer ersten Ausführungsform; und
• 5 eine schematische Darstellung eines Verfahrens zum Pumpen von Waschflüssigkeit aus einem Laugenbehälter eines Wäschepflegegeräts.

Show it:

• 1 a schematic view of a laundry care device;
• 2 a schematic view of a pumping system of a laundry care device with a variable-speed pump;
• 3 a graphical representation of a conventional pumping operation in a laundry care device;
• 4 a diagram of a pumping operation in a laundry care device according to a first embodiment; and
• 5 a schematic representation of a method for pumping washing liquid from a tub of a laundry care device.

1 shows a schematic view of a general laundry care device 100 , such as a washing machine. The laundry care device 100 includes an induction bowl 101 , in which detergents or other liquid substances can be filled. The laundry care device 100 includes a door 103 for loading the laundry care device 100 with laundry.

2 shows a schematic view of a pumping system of a laundry care device with a variable speed pump. The laundry care device 100 has a tub 105 for receiving washing liquid, and has a laundry drum 107 for receiving laundry. The laundry drum 107 has a drum base 109 on. The tub 105 has a drain opening 111 on. The laundry care device 100 has an inlet nozzle 113 on. The drain opening 111 is through a lead 115 with the inlet nozzle 113 fluidly connected, wherein in the line 115 a variable speed pump 117 for pumping washing liquid through the line 115 is arranged. The variable speed pump 117 can wash fluid through the drain opening 111 from the tub 105 during a in 2 Pumping process not shown in the line 115 pump off and the pumped washing liquid through the line 115 and through the inlet nozzle 113 the laundry drum 107 feed again. As a result, the fresh scrubbing liquid can effectively pass through the conduit during a laundry care process 115 be pumped and the laundry in the laundry drum 107 be fed again. As a result, the laundry care success during a laundry care process can be improved by a higher cleaning effect.

The laundry care device 100 further includes a controller 119 , which with the variable speed pump 117 through a first control connection 121 connected, and which with a power sensing element 123 is connected by a second control connection 125, wherein the power detection element 123 with the variable speed pump 117 through a third control connection 127 connected is. The service entry element 123 detects an electric power value of the variable speed pump 117 wherein the detected electrical power value is a volumetric flow through the variable speed pump 117 subsidized washing liquid corresponds. The control 119 is formed, the pump speed of the variable-speed pump 117 depending on the detected electric power value of the variable-speed pump 117 to control.

The laundry care device 100 further comprises an outlet conduit 129 which with the line 115 fluidly connected. The variable speed pump 117 is trained during a in 2 Not shown Abpumpvorgangs washing liquid through the discharge opening 111 from the tub 105 , through the pipe 115 and through the outlet pipe 129 from the laundry care device 100 pump out.

It is emphasized that a laundry care device 100 not necessarily a pumping system must have, but the variable-speed pump 117 also in a laundry care device 100 can be arranged without Umpumpsystem, in which case the line 115 excluding the tub 105 with the pump 117 fluidly connects and the line 115 not from the pump 117 to the Inlet nozzle 113 of the laundry care device 100 is guided.

3 shows a graphical representation of a conventional pumping operation in a laundry care device. 3 shows a time chart of a normalized pump speed of a variable speed pump 117 , and the scaled volume flow through the variable speed pump 117 promoted washing liquid, all along the ordinate axis 131 depending on the time in seconds, which along the abscissa axis 133 is given, are applied.

The first turn 135 shows the course of the normalized pump speed of a variable-speed pump 117 , The second turn 137 shows the progression of the scaled volume flow through the variable speed pump 117 promoted washing liquid.

During a first pumping interval 139 is in the tub 105 a sufficient amount of washing liquid, thereby ensuring that the variable speed pump 117 when pumping the washing liquid from the tub 105 no air with pumps. As in 3 can be seen, thus, the variable-speed pump 117 during the first pumping interval 139 consistently with a nominal pump speed 141 be operated without the volume flow of the washing liquid breaks off, as from the course second curve 137 during the first pumping interval 139 It can be seen here that there is a constant nominal volume flow 143 is maintained. Will the variable speed pump 117 at the end of the first pumping interval 139 deactivated, the volume flow of the variable-speed pump also decreases 117 promoted washing liquid to zero. It is emphasized that the activation or deactivation of the variable speed pump 117 through the controller 119 leads to a time-delayed increase or decrease in the volume flow of the pumped washing liquid.

During a second pumping interval 145 is in the tub 105 not enough washing liquid. When the variable speed pump 117 during the second pumping interval 145 with the nominal pumping speed 141 is operated, it comes to a demolition of the volume flow of the washing liquid, since air from the tub 105 into the variable speed pump 117 forced out. This reduces the nominal volume flow .143 during the second pumping interval 145 abruptly. The ventilated pump 117 the air must be removed from the pump for a renewed volume flow build-up 117 displace both the suction side and the pressure side, so that again the nominal volume flow 143 can adjust if the suction side of the pump 117 again accumulated a Rückstaumenge the abzupumpenden washing liquid has accumulated. This air displacement process and thus the re-forming of the nominal volume flow 143 Often, this can only be very time-delayed, because the suction-side pump flow inside the pump 117 formed by the impeller rotation induced vortex, which has low core pressures due to the high peripheral speeds and thus collects the air dissolved in the flow of air around the vertebral center axis and centered. As a result, the standing vortex collects the air on the suction side and thus blocks the fresh flow of the washing liquid at the suction mouth of the pump 117 , A suction-side damming the freewheeled washing liquid is the result, so that the Waschflüssigkeitsrückstaumenge washing liquid levels in the tub 105 generated where the rotating laundry drum 107 can submerge in the washing liquid, thereby increasing the engine torque of a drum drive excessively, so that the spin process may need to be stopped.

As in the second turn 137 is shown, the volume flow increases during the second pumping interval 145 only slowly, until again the nominal volume flow 143 is reached. For this reason, it is sought after procedural possibilities to realize the fastest possible pump restart with pending Waschflüssigkeitsrückstaumenge.

4 shows a graphical representation of a pumping operation in a laundry care device according to a first embodiment. Analogous to 3 show the 4 also a time representation of a normalized pump speed of a variable-speed pump 117 , and the scaled volume flow through the variable speed pump 117 promoted washing liquid, all along the ordinate axis 131 depending on the time in seconds, which along the abscissa axis 133 is given, are applied.

The first turn 135 shows the course of the normalized pump speed of a variable-speed pump 117 , The second turn 137 shows the progression of the scaled volume flow through the variable speed pump 117 promoted washing liquid.

As in 4 can be seen, the variable speed pump 117 during a first pumping interval 139 consistently with a nominal pump speed 141 and with a nominal volume flow 143 be operated without the volume flow of the washing liquid breaks off, as in the tub 105 a sufficient amount of washing liquid is available.

The second pumping interval 145 is in a first period of time 147 , a second period of time 149 a third period of time 151 and a fourth time period 153 divided.

During the first period 147 becomes the variable speed pump 117 with a nominal pumping speed 141 operated, so that a nominal volume flow 143 established. At the end of the first period 147 is through the pump 117 Air from the tub 105 aspirated, whereby the volume flow of the pumped washing liquid drops.

During the first period of time 147 subsequent second period 149 reduces control 119 the nominal pumping speed 141 the pump 117 to a minimum pump speed 155 when the flow through the pump 117 pumped washing liquid a volume flow minimum threshold 157 below.

The variable speed pump 117 has a variable speed permanent magnet synchronous motor, whereby the detection of the operating parameters of the current pump state of the pump 117 lets recognize. Thus it can be detected, whether the pump 117 has pumped the entire volume flow within the nominal pump speed 141 or, for example, has sucked in air, the flow has been torn off and the pump 117 has built only a pressure column and is thus in the so-called "snorkel" or "Schlürf-operation", while the volume flow minimum threshold 157 below. Because for these different operating conditions, there is also a different power requirement of the pump 117 a, which can be detected via a different engine torque and thus a different torque-generating current I _q .

During the second period 149 subsequent third period 151 increases the control 119 the minimum pump speed 155 the pump 117 to a maximum pump speed 159 when the volume flow of the pumped wash liquid again the volume flow minimum threshold 157 reached. The maximum pumping speed 159 is greater than the minimum pumping speed 155 and the nominal pump speed 141 of the pump 117 to get an air swirl in the pump 117 effective to remove.

Due to the rapid succession of reducing the pump speed and increasing the pump speed of the pump 117 , It is achieved that the suction-induced induced air vortex in front of the impeller of the pump 117 collapses, the air in the pressure chamber of the pump 117 is pulled and this is then pumped with the faster building up volume flow of the washing liquid. Thus, it can thus be procedurally achieved that, when sufficiently large volumes of washing liquid are again present on the suction side, the induced, air-filled vortex is dissolved as a result of the temporally rapid succession of variation of the pumping speed.

During the third period 151 subsequent fourth time section 153 reduces the control 119 the maximum pump speed 159 the pump 117 again to the nominal pump speed 141 the pump 117 when the flow rate through the variable speed pump 117 pumped washing liquid again the nominal volume flow 143 achieved, whereby the washing liquid effectively and effectively from the tub 105 of the laundry care device 100 can be pumped out.

In this case, the advantage is achieved that after a flow break, a centrifugal or pumping abort can be avoided. If you do not pay attention to a suction side structure of the Waschflüssigkeitsrückstaumenge, there is a risk that the laundry drum 107 immersed in the back-flowed washing liquid and this foams unnecessarily, whereby the pumping out of the washing liquid is made even more difficult, the drive torque of the laundry drum 107 is unnecessarily increased and thus the life of the drum drive and the entire oscillating system is reduced.

The problem described here in terms of pumping not only arises in a spin process, but can also occur in the washing process, in the case of large-volume laundry care appliances 100 often a pumping system is used to speed up the laundry wetting process and process optimization of the washing process. In this Umpumpprozess the Wasserrückstaumenge is using a pump via a pressure-side circulation hose via an inlet nozzle 113 the laundry again. Thus, even during the pumping process, similar to the pumping process in the spin process section, the task of realizing the rapid pump restart with collecting water backpressure after a tapped flow has been achieved.

For the high drum rotation speeds of in particular more than 100 U / min, due to the prevailing centrifugal force, a full laundry throughput can only be achieved with the aid of a pumping system. If an unnecessarily long wait after a detected volume flow break until a new start of the flow of the washing liquid is performed, thereby the laundry can not be sufficiently watered and the washing effect of this washing phase can fall off. Nevertheless, in order to achieve the same washing effect, the washing time must be significantly extended, whereby the user of the laundry care device 100 has to wait longer, and also a larger drive power is needed to operate the longer washing process.

5 shows a schematic representation of a method for pumping washing liquid from a tub of a laundry care device.

The procedure 200 comprises activation as the first method step 201 the variable speed pump 117 and operating the variable speed pump 117 with a nominal pumping speed 141 through the controller 119 during a first period of time 147, to wash liquid having a nominal volume flow 143 from the tub 105 and through the pipe 115 pump out.

The procedure 200 comprises reducing as a second method step 203 the nominal pump speed 141 the variable speed pump 117 to a minimum pump speed 155 through the controller 119 during one at the first time period 147 subsequent second period of time 149 when the flow rate through the variable speed pump 117 pumped washing liquid a volume flow minimum threshold 157 below.

The procedure 200 includes as the third step, the increase 205 the minimum pump speed 155 to the maximum pump speed 159 through the controller 119 during one to the second period 149 subsequent third period of time 151 when the flow rate through the variable speed pump 117 pumped washing liquid the volume flow minimum threshold 157 achieved, with the maximum pump speed 159 greater than the minimum pump speed 155 and the nominal pump speed 141 is to get an air swirl in the variable speed pump 117 to remove.

The procedure 200 includes reducing as the fourth method step 207 the maximum pump speed 159 the variable speed pump 117 to the nominal pump speed 141 through the controller 119 during one to the third time period 151 subsequent fourth period of time 153 when the flow rate through the variable speed pump 117 pumped washing liquid the nominal volume flow 143 reached to wash liquid again with the nominal volume flow 143 effective from the tub 105 and pump through the conduit 115.

All features explained and shown in connection with individual embodiments of the invention may be provided in different combinations in the article according to the invention, in order to simultaneously realize their advantageous effects.

The scope of the present invention is given by the claims and is not limited by the features illustrated in the specification or shown in the figures.

LIST OF REFERENCE NUMBERS

100

Laundry care device

101

dispenser tray

103

door

105

tub

107

washing drum

109

Drum base

111

drain hole

113

inlet nozzle

115

management

117

, Variable speed pump

119

control

121

First control connection

123

Power sensing element

125

Second control connection

127

Third control connection

129

outlet pipe

131

axis of ordinates

133

abscissa

135

First turn

137

Second turn

139

First pumping interval

141

Nominal pumping speed

143

Nominal flow

145

Second pumping interval

147

First period

149

Second period

151

Third period

153

Fourth period

155

Minimum pump speed

157

Volume flow minimum threshold

159

Maximum pump speed

200

Process for pumping washing liquid from a tub

201

First step: Activate the variable speed pump

203

Second process step: Reduction of the nominal pumping speed of the variable-speed pump

205

Third step: Increase the minimum pump speed of the variable speed pump

207

Fourth step: Reduce the maximum pump speed of the variable speed pump

Claims (15)

A laundry care appliance (100) with a washing tub (105) for receiving washing liquid, wherein the liquor container (105) has a discharge opening (111), wherein the discharge opening (111) is fluidly connected to a conduit (115), wherein in the conduit (115 ) is arranged a variable speed pump (117) for pumping washing liquid from the tub (105) and through the conduit (115), and a controller (119) for controlling the variable speed pump (117), characterized in that the controller (119 ) is configured to activate the variable speed pump (117) and operate at a nominal pumping speed (141) during a first period (147) to deliver wash fluid having a nominal volume flow (143) from the tub (105) and through the conduit (115). in that the control unit (119) is designed to reduce the nominal pumping speed (141) during a second time period (149) adjoining the first period of time (147) speed variable pump (117) to a minimum pump speed (155) when the volume flow of the wash fluid pumped by the variable speed pump (117) falls below a minimum volume flow threshold (157) that the controller (119) is formed during a second time period (149) subsequent third period (151) to increase the minimum pump speed (155) of the variable speed pump (117) to a maximum pump speed (159) when the volume flow of the wash pumped by the variable speed pump (117) reaches the minimum volume flow threshold (157) the maximum pumping speed (159) is greater than the minimum pumping speed (155) and the nominal pumping speed (141) is to remove a stationary air vortex at a pump suction port of the variable speed pump (117) and two phase dissolved air in a pump pressure chamber of the variable speed pump (117); that the controller (119) is formed during a fourth period (153) subsequent to the third period (151) reduces the maximum pump speed (159) of the variable speed pump (117) to the nominal pump speed (141) when the volume flow of the wash pumped by the variable speed pump (117) is the nominal volume flow (143) to effectively pump wash liquid with the nominal volume flow (143) out of the tub (105) and through the conduit (115). Laundry care appliance (100) after Claim 1 , characterized in that the controller (119) is adapted, after the end of the second period (149), the minimum pump speed (155) of the variable speed pump (117) at the beginning of the third period (151) without time delay to the maximum pump speed (159) or that the controller (119) is arranged, after the end of the second period (149), to increase the minimum pumping speed (155) of the variable speed pump (117) to the maximum pumping speed (159) after an intermediate time interval during the third period (151) In particular, the intermediate time interval is between 1 second and 5 seconds. Laundry care appliance (100) after Claim 1 or 2 characterized in that the laundry care device (100) comprises a program selector for selecting a laundry maintenance program or a weight detecting device for detecting a weight of laundry in a laundry drum (107) of the laundry machine (100), the controller (119) being adapted to determine the duration of the laundry Or the controller (119) is adapted to adjust the speed profile of the variable speed pump (117) in dependence on the selected laundry care program and / or the detected weight of the laundry. Laundry care appliance (100) according to one of the preceding claims, characterized in that the variable-speed pump (117) comprises an electric motor, in particular a permanent-magnet brushless synchronous drive. The laundry care appliance (100) according to any one of the preceding claims, characterized in that the laundry care appliance (100) comprises a power detection element (123) for detecting an electric power value of the variable speed pump (117), wherein the controller (119) is adapted to control the nominal pumping speed (141 ) of the variable speed pump (117) to the minimum pump speed (155) during the second time period (149) when the detected electric power value is less than a minimum reference power value, the minimum reference power value corresponding to an electric power value variable speed pump (117) when pumping out wash fluid with the volume flow minimum threshold (157). Laundry care appliance (100) after Claim 5 characterized in that the controller (119) is configured to increase the minimum pump speed (155) of the variable speed pump (117) to the maximum pump speed (159) during the third time period (151) when the sensed electric power value reaches the minimum reference power value. Laundry care appliance (100) after Claim 5 or 6 characterized in that the controller (119) is configured to reduce the maximum pump speed (159) of the variable speed pump (117) to the nominal pump speed (141) during the fourth time period (153) when the sensed electric power value reaches a nominal reference power value the nominal reference power value corresponds to an electrical power value of the variable-speed pump (117) when pumping washing fluid with the nominal volume flow (143). Laundry care appliance (100) according to one of Claims 5 to 7 characterized in that the power detecting element (123) comprises a power sensor for detecting an electric power of the variable speed pump (117) or a current sensor for detecting a power supply of the variable speed pump (117). The laundry care device (100) according to any one of the preceding claims, characterized in that the laundry care device (100) comprises a flow sensor for detecting a flow velocity of the washing liquid pumped by the variable speed pump (117), the controller (119) is adapted to the nominal pumping speed (141 ) of the variable speed pump (117) to the minimum pump speed (155) during the second time period (149) when the detected flow rate is less than a reference flow rate value and wherein the controller (119) is configured to set the minimum pump speed (155) during the third time period (151) to the maximum pump speed (159) when the detected flow rate reaches the reference flow rate value, wherein the reference flow rate value corresponds to a flow rate value of the washing liquid when pumping out washing liquid having the volume minimum threshold (157). The laundry care device (100) according to any one of the preceding claims, characterized in that the laundry care device (100) comprises a level sensor for detecting a level of washing liquid in the tub (105) that the controller (119) is formed, the nominal pumping speed (141) reduce the minimum pump speed (155) during the second period (149) when the detected level falls below a minimum level, and the controller (119) is configured to set the minimum pump speed (155) to the maximum pump speed (159) during the third period (151 ) when the detected level reaches the minimum level again. The laundry care appliance (100) according to one of the preceding claims, characterized in that the laundry care appliance (100) has an inlet nozzle (113) for introducing washing liquid into the tub (105), wherein the drain opening (111) of the tub (105) with the inlet nozzle (113) is fluidly connected by the conduit (115), and wherein the variable speed pump (117) is adapted to pump washing liquid through the discharge port (111) from the tub (105) into the conduit (115) and the pumped washing liquid through the Line (115) and pump through the inlet nozzle (113) back into the tub (105). The laundry care appliance (100) according to any one of the preceding claims, characterized in that the controller (119) is formed during a spin process performed by the laundry care appliance (100), the variable speed pump (117) during the first, second, third and fourth time periods ( 147, 149, 151, 153). Method (200) for pumping washing liquid from a tub (105) of a laundry care device (100), wherein the laundry care device (100) comprises a tub (105) for receiving washing liquid, wherein the tub (105) has a discharge opening (111) wherein the discharge opening (111) is fluidly connected to a conduit (115), wherein in the conduit (115) is arranged a variable speed pump (117) for pumping washing liquid from the tub (105) and through the conduit (115), and a controller (119) for controlling the variable speed pump (117), characterized in that the method (200) comprises the steps of activating (201) the variable speed pump (117) and operating the variable speed pump (117) with a Nominal pumping speed (141) by the controller (119) during a first time period (147) to wash fluid having a nominal volume flow (143) from the tub r (105) and through the conduit (115), reducing (203) the nominal pumping speed (141) of the variable speed pump (117) to one Minimum pump speed (155) by the controller (119) during a second period (149) subsequent to the first period (147) when the volume flow of the washing fluid pumped by the variable speed pump (117) is less than a minimum volume flow threshold (157); ) the minimum pump speed (155) to the maximum pump speed (159) by the controller (119) during a third time period (151) subsequent to the second time period (149) when the volume flow of the wash fluid pumped by the variable speed pump (117) is the minimum volume flow threshold (157), wherein the maximum pumping speed (159) is greater than the minimum pumping speed (155) and the nominal pumping speed (141) to detect a stationary air vortex at a pump suction port of the variable speed pump (117) and two phase dissolved air in a pump pressure chamber of the variable speed pump (157). 117), and reducing (207) the maximum pump speed (159) of the variable speed pump (117) to the nominal pump speed (141) by the controller (119) during a fourth period (153) subsequent to the third period (151) when the volume flow through the variable speed pump (117) pumped washing liquid reaches the nominal volume flow (143), in order to pump the washing liquid again with the nominal volume flow (143) effectively from the tub (105) and through the line (115). Method (200) according to Claim 13 characterized in that the laundry care apparatus (100) comprises a power detection element (123) for detecting an electric power value of the variable speed pump (117), and wherein the method (200) comprises the steps of reducing (203) the nominal pumping speed (141) during the second period (149), when the sensed electric power value is less than a minimum reference power value, the minimum reference power value is an electric power value of the variable speed pump (117) upon pumping out washing fluid corresponds to the volume flow minimum threshold (157). Increasing (205) the minimum pump speed (155) to the maximum pump speed (159) by the controller (119) during the third time period (151) when the sensed electric power value reaches the minimum reference power value, reducing (207) the maximum pump speed (159) to the nominal pump speed (141) by the controller (119) during the fourth time period (153) when the detected electrical power value reaches a nominal reference power value, wherein the nominal reference power value corresponds to an electric power value of the variable speed pump (117) when pumping wash fluid to the nominal volume flow (143). Method (200) according to Claim 13 or 14 characterized in that increasing (205) the minimum pump speed (155) to the maximum pump speed (159) without time delay after reducing (203) the nominal pump speed (141) to the minimum pump speed (155) or the method (200) is on Intermediate interval between reducing (203) the nominal pumping speed (141) to the minimum pumping speed (155) and increasing the minimum pumping speed (155) to the maximum pumping speed (159), wherein the intermediate time interval is in particular between 1 second and 5 seconds.

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