Washing machine

Abstract

 Washing machine (1) and method for operating a washing machine, wherein the washing machine comprises a tub (2), a draining circuit (16), wherein the draining circuit (16) is fluidly connected to a lower portion of the tub (2), a valve (26) arranged between the tub (2) and the draining circuit (16), a recirculation circuit (10) fluidly connected to the tub (2), wherein an inlet (14) of the recirculation circuit (10) is positioned downstream a valve seat (22) of the valve (26), and wherein the recirculation circuit comprises a recirculation pump (12) for re-circulating fluid from the lower portion of the tub (2) into the tub (2), and a control unit adapted to control the washing machine to perform at least one washing cycle, wherein the valve (26) is adapted to be opened when the recirculation pump (12) is operated and is adapted to be closed when the recirculation pump (12) is not operated, and wherein said control unit is adapted to operate said recirculation pump (12) and said draining pump (18) simultaneously for at least one time interval during at least one draining phase and/or during at least one spinning phase of the washing cycle.

Description

[0001] The invention relates to a washing machine (including a washing machine having a dryer function and/or a front- or top-loading washing machine) with a recirculation circuit and a draining circuit comprising a valve adapted to selectively open and close the passage of liquid from a tub to the draining circuit.

[0002] EP 1 204 792 B1 discloses a washing machine, wherein an inlet of a draining circuit is fluidly connected to a sump. A check valve is arranged between the sump and the inlet of the draining circuit. During a washing cycle the check valve shuts off the sump from the draining circuit by using a valve seat and a ball as closing element. A recirculation circuit is provided for circulating washing water from the sump to an upper portion of the tub.

[0003] It is an object of the invention to provide a washing machine and method which allow an improved washing operation.

[0004] The invention is defined in claim 1 and 11, respectively. Particular embodiments are set out in the dependent claims.

[0005] In the following, when reference is made to 'water', the term 'water' may denote water as such, washing water, washing liquid, washing liquor or the like.

[0006] According to claim 1, a washing machine comprises a tub, a rotatable drum within the tub and a draining circuit, which is fluidly connected to the tub to drain water from the tub. E.g. the draining circuit is connected or attached to the tub or the tub may comprise a sump and the draining circuit is attached or connected to the sump. A valve is arranged between the tub and the draining circuit. E.g. the valve is adapted to shut off or seal the tub from the draining circuit, in particular during a heating phase of a washing cycle of the washing machine. A control unit of the washing machine is adapted to control the washing machine to perform one or more washing cycles, e.g. a washing cycle for cotton at 60°C or a cycle for delicate fabrics at 30°C. The washing machine further comprises a recirculation circuit having a recirculation pump, which is fluidly connected to the tub, wherein an inlet of the recirculation circuit is positioned downstream a valve seat of the valve. Thus when operating the recirculation pump, water from the bottom of the tub is re-circulated preferably to an upper or middle portion of the tub to be sprayed or sprinkled onto laundry in the tub. In particular when the valve is in the closed position to shut the tub off from the draining circuit, the inlet of the recirculation circuit is positioned or arranged to be fluidly connected to the draining circuit, preferably close to the valve.

[0007] The valve is adapted to be opened when the recirculation pump is operated and is adapted to be closed when the recirculation pump is not operated, in particular during a washing cycle. E.g. the valve is closed in dependency of a water level in the draining circuit and/or tub, for example by a closure element which is floating in or on the water and which is pressed against a valve seat when the water level in the draining circuit and/or tub rises during a water supply phase. When the recirculation pump is operated, the suction force of the recirculation pump (with the inlet of the recirculation circuit placed below the valve or downstream the valve as seen from the tub) opens the valve, e.g. by removing the closure element from the valve seat. Thus the valve is actuated by the operation of the recirculation pump, for example due to a pressure difference of the water between the tub and the inlet of the recirculation circuit below the valve generated by the (operating) recirculation pump.

[0008] The valve is arranged between the tub and the draining circuit, thus the valve is opened when the draining pump is operated, i.e. due to the pressure difference between the tub and the draining circuit generated by the (operating) draining pump. During a washing cycle the valve has to be opened repeatedly, e.g. in a (final) draining phase and during or after a spinning phase when water which has been extracted from the laundry due to drum rotation has to be drained from the tub. Thus to open the valve and to drain the water from the tub the draining pump is (repeatedly) activated during a washing cycle.

[0009] The presence of foam or air bubbles and/or a (local) depression or low pressure within the tub, e.g. due to the rotation of the drum in a spinning phase of the washing cycle, might prevent the opening of the valve during a draining phase and/or a spinning phase of the washing cycle.

[0010] According to the invention, the control unit is adapted to operate the recirculation pump and the draining pump simultaneously for at least one time interval during at least one draining phase and additionally or alternatively during at least one spinning phase of the washing cycle. In particular a draining phase advantageously starts with the activation or switching-on of the draining pump and ends with the deactivation or switching-off of the draining pump. A spinning phase advantageously starts with the start of drum rotation and ends at the end of drum rotation; advantageously, during and/or after a spinning phase water is drained from the tub by operating the draining pump. Thus the spinning phase may comprise and/or is followed by a draining period or draining phase.

[0011] By operating the recirculation pump and the draining pump simultaneously the combined suction force of both pumps act on the valve. In particular as both pumps are operated simultaneously for at least one (preferably short, e.g. 1 second) time interval the pressure drops at the valve and acts as a (preferably short, e.g. 1 second) pressure impulse upon the valve or closure element and opens the valve. Thus the simultaneous operation of the draining pump and the recirculation pump for said at least one time interval helps opening the valve also in conditions (e.g. foam, depression) which may make the opening of the valve difficult. Thereby the above described washing machine is improved and provides a constant good washing performance as the valve is safely and reliably opened also in unfavourable conditions.

[0012] Preferably at least one of said time intervals is at least 0.3, 0.4, 0.5, 0.8, 1, 2, 3, 4, 5, 10, 20, 40 or 60 seconds. More preferably at least one of said time intervals is in the range of 1 to 60 seconds. By operating the recirculation and draining pump simultaneously for at least one short time interval a short pressure impulse acts on the valve and helps its opening, while the short simultaneous operation of both pumps has almost no impact on the energy consumption of the washing machine.

[0013] In a preferred embodiment the control unit is adapted to operate said recirculation pump and said draining pump simultaneously for a plurality of said time intervals or repeatedly for said time intervals. Due to the repeated operation of the recirculation pump, i.e. the recirculation pump is intermittently operated or is switched-on and -off repeatedly, a plurality of pressure impulses act on the valve which help e.g. loosen the closure element and open the valve.

[0014] Preferably the control unit is adapted to start operation of the recirculation pump and the draining pump simultaneously. The simultaneous start results in sudden negative (i.e. directed towards the external of the tub) pressure acting on the valve which is higher than when one pump is started or activated after the other. Thus a higher pressure impulse acts on the valve which opens the valve reliably.

[0015] Preferably the control unit is adapted to start operation of the recirculation pump and the draining pump simultaneously after a non-operation time of the draining and recirculation pump of duration of at least 0.5, 1, 2, 3, 4 or 5 seconds. Thus a waiting time is provided before (re)starting the draining and the recirculation pump. Due to the waiting time the pressure within the draining circuit equilibrates (e.g. to atmospheric pressure), whereby the pressure drop at the valve is steeper when the draining pump and the recirculation pump operate or start to operate simultaneously.

[0016] According to a preferred embodiment the draining pump and/or the recirculation pump is executing a series of at least two start/stop intervals. For example the recirculation pump is intermittently operated, i.e. starts and stops operation at least two times, during the at least one draining phase and/or the at least one spinning phase. Additionally or alternatively both pumps start and stop operation simultaneously for at least two times. Due to the intermittent operation a pressure difference builds up between the draining circuit below the valve and the tub, i.e. with each start/stop interval the pressure difference increases until the valve is opened. Preferably a non-operating period between the start/ stop intervals is less than 5, 4, 3, 2, 1, 0.5 seconds to allow the pressure difference to build up, i.e. to prevent that the pressure equilibrates during the non-operating periods of the start/stop intervals.

[0017] Preferably the control unit is adapted to operate said recirculation pump and said draining pump simultaneously at the beginning of at least one of the draining phases, such that the valve is reliably opened at the beginning of a draining phase. Advantageously the control unit is adapted to operate the recirculation pump for said at least one time interval at the start of operating of the draining pump.

[0018] Preferably the control unit is adapted to operate said recirculation pump and said draining pump simultaneously during a drum rotation period of at least one of said spinning phases. As described above the drum rotation may cause low pressure within the tub such that the valve remains closed although the draining pump operates or starts operating. Thus the simultaneous operation of the pumps during a spinning phase safely opens the valve to drain water extracted from the laundry from the tub. For example the draining pump and the recirculation pump are operated simultaneously for at least one time interval at the start of a spinning phase to safely open the valve at the beginning of the spinning phase. Additionally or alternatively the control unit is adapted to operate said recirculation pump and said draining pump simultaneously at the end of at least one said spinning phases or at least at the final spinning phase, such that at least at the end of a spinning phase the valve is open to drain water from the tub.

[0019] Preferably the valve comprises a valve body having the valve seat and a movable closure element adapted to be releasably engaged with the valve seat for closing the opening through the valve seat. E.g. the closure element floats on the water that fills the draining circuit or a sump and is eventually pressed towards the valve seat by the rising water level, i.e. by buoyant force, and seals thereby a valve opening in the valve seat. Thereby the tub is shut off from the draining circuit, wherein a simple and robust valve is provided which is maintenance-free or is substantially maintenance-free.

[0020] Preferably the movable closure element has a spherical or substantially spherical shape, such that it may engage with the valve seat in any (rotated) position. This is advantageous when the closure element is freely floating within the sump or draining circuit. Alternatively the closure element is formed by a hinged flap, e.g. like in a swing check valve, which is closed by buoyant force and water pressure.

[0021] In an embodiment the valve body is formed by the sump container or a portion thereof or by a portion of a draining suction duct connecting the tub to a draining pump. Thus the number of elements for providing the valve is reduced as compared to a valve having a separate body. In case the inlet of the recirculation circuit is arranged at a bottom or lower region of the valve body, the recirculation circuit has an improved ability to suck in undissolved detergent that has collected at the lower region of the valve body (e.g. sump or draining suction duct) due to gravity.

[0022] With respect to the method of the invention, full reference is made to above description of the washing machine and the described operation modes and advantages thereof as well as to the below detailed description. In particular the various above described operating modes for operating the draining pump and the recirculation pump simultaneously during a draining phase and/or a spinning phase can be combined in any arbitrary way for a plurality of draining and spinning phases of a washing cycle. For embodiments of the washing machine or the method, each isolated feature of the claims or description can be added or any arbitrary combination of isolated or individual features can be added to the claims.

[0023] Reference is made in detail to a preferred embodiment of the invention, an example of which is illustrated in the accompanying figures, which show:

Fig. 1

a schematic cross-sectional front view of a washing machine according to the invention,

Fig. 2

a schematic cross sectional front view of the washing machine of Fig. 1 during filling of water into a tub thereof,

Fig. 3

a schematic cross sectional view of the washing machine of Fig. 1, wherein the tub is partially filled with water,

Fig. 4

a schematic cross sectional front view of the washing machine of Fig. 1 during a recirculation interval,

Fig. 5

a schematic cross sectional front view of the washing machine of Fig. 1 during a draining phase,

Fig. 6

a schematic cross sectional front view of the washing machine of Fig. 1 during a simultaneous operation of a recirculation pump and a draining pump

Fig. 7

a perspective, partially cross-sectional side view of a part of an exemplary internal structure of a washing machine,

Fig. 8

a perspective, partially cross-sectional side view of the internal structure of the washing machine shown in Fig. 7,

Fig. 9

a partial cross-sectional top view of a detail of the structure of the washing machine shown in Fig. 7,

Figs. 10a-d

perspective views and cross sectional views of a ball valve as shown in Fig. 7,

Fig. 11

a cross-sectional side view of the ball valve of Figs. 10a-d in a closed state, and

Fig. 12

a cross-sectional side view of the ball valve of Fig. 10a-d in an opened state.

[0024] Fig. 1 depicts a schematic cross-sectional front view of a washing machine 1 comprising a tub 2 with a drum 4 rotatably arranged therein. A control unit (not shown) is provided to control one or more washing cycles or washing programs of the washing machine. A draining circuit 16 preferably comprises a draining pump 18, a draining suction pipe 17, a draining riser pipe 19 and a draining filter 20. The draining suction pipe 17 is fluidly connected to the tub 2 to drain water, washing water or fluid from the tub 2 during a draining phase when the draining pump 18 is operated. A valve 26 comprising a valve body 27 and a valve seat 22 in form of a diaphragm with an opening is arranged between the tub 2 and the draining circuit 16. A ball 24 which is freely moveable or floatable between the valve seat 22 and a filter element 28 is adapted to engage with the valve seat 22 to shut the tub 2 from the draining circuit 16. According to an alternative embodiment no filter element 28 is provided, wherein for example the draining suction pipe 17/ valve body 27 is formed such that the ball 24 is freely floatable within the draining circuit 16, i.e. within the draining suction pipe 17/ valve body 27. The ball 24 is made of floatable material e.g. plastic and floats on the water depending on the water level in the draining suction pipe 17/ valve body 27. When the water level rises, the ball 24 is raised towards the valve seat 22 until the ball surface closes the opening at the valve seat 22. The valve seat 22 may be formed in a diaphragm or plate as shown in Fig. 1. In the depicted embodiment the draining suction pipe 17 is pipe-shaped and forms (at least part of) the sump and the valve body 27 connected to the lowest point for the tub 2. However in other embodiments the draining suction pipe 17 may have different shapes at least in the region directly below the opening to the tub.

[0025] A recirculation circuit 10 is provided to circulate water or washing water from a lower portion of the tub 2 to an upper portion of the tub 2 in the embodiment shown. The recirculation circuit 10 preferably comprises a suction pipe 13 fluidly connected to the draining suction pipe 17 (forming the sump), a recirculation pump 12 and a recirculation pipe 11. When the recirculation pump 12 is operated, the laundry 44 in the tub 2 is efficiently wetted without having to provide an amount of water in the tub 2 which completely covers the laundry 44. I.e. on the one hand the water consumption during a washing cycle is reduced and on the other hand, due to reduced water consumption less water has to be heated, whereby the energy consumption is reduced.

[0026] Advantageously, the recirculation pump 12 and the draining pump 18 are not completely watertight. Thus the water level in the recirculation pipe 11 and the draining riser pipe 19 corresponds to the water level in the tub 2 or draining suction pipe 17 when the pumps 12 and 18 are not operated and the ball valve 26 is open.

[0027] The filter element 28 is advantageously arranged downstream the ball valve seat 22 in front of an inlet 14 of suction pipe 13 of the recirculation circuit 10. When the recirculation pump 12 is operated, the water passes the filter element 28 before it enters the recirculation circuit 10. The filter element 28 prevents that fluff and foreign objects which may pass through the opened or partially opened valve 26 enter the recirculation circuit 10, where they might obstruct a nozzle at the outlet of the recirculation pipe 11 or the recirculation pump 12. When no water is in the draining circuit 16, the recirculation pump 12 is operated or the water level is low, the ball 24 rests on the filter element 28.

[0028] Figs. 2 to 6 show the washing machine in different phases during a washing cycle, which is controlled by the control unit. An exemplary washing cycle preferably comprises a starting phase, wherein water and detergent are supplied into the tub 2, a heating phase, wherein water in the tub 2 is heated, a washing phase, wherein laundry 44 in the tub 2 is treated/washed, e.g. by repeatedly changing the rotation direction of the drum 4, and a rinsing phase, wherein laundry 44 is rinsed with fresh water, i.e. washing water and detergent is removed from the laundry 44 and the tub 2. During the washing cycle the draining pump 18 is repeatedly operated to drain water from the tub. For example during or after a spinning phase to drain (dirty or used) water which is extracted from the laundry 44 by rotating the drum 4 from the tub 2 and/or during a final draining phase at the end of the washing cycle before the laundry 44 is removed from the drum 4 by a user.

[0029] Fig. 2 depicts a schematic cross sectional front view of the washing machine of Fig. 1 at the beginning of a washing cycle, i.e. a starting phase of a washing cycle. As depicted by arrows, tap water flows into the tub 2 via a water inlet 6. The tap water flows through the detergent drawer 8, from where it carries detergent into the tub 2 and drum 4 as indicated with the arrows. In this state the water level 42a is in a range where the ball 24 is not abutting the valve seat 22 such that the valve 26 is open. Thus the water fills the draining circuit 16 and partially the recirculation circuit 10.

[0030] Fig. 3 depicts a schematic cross sectional view of the washing machine of Fig. 1 at a later point in time of the starting phase, where a water supply phase is finished and the tub 2 is filled with water up to the maximum water level 42b for the selected washing program or cycle, respectively. In this phase the draining pump 16 and the recirculation pump 12 are not activated, thus the valve 26 is closed. The washing water has reached maximum level 42b which partially covers the laundry 44 in the tub 2. While the water level was rising from level 42a to 42b and due to the hydrostatic buoyant force, the ball 24 is pushed or pressed against the valve seat 22 and closes thereby the valve 26. The valve 26 provides a simple and robust way for automatically shutting off the tub 2 from the draining circuit 16 during those phases of the washing cycle, in which the pumps 12, 18 are not operated and in which the water level has a minimum height to press the ball 24 against the valve seat 22. In particular the valve 26 is closed during a heating phase of the washing cycle when the water is filled to close the valve 26 and when no pumps 12, 18 are operated.

[0031] Fig. 4 depicts a schematic cross sectional front view of the washing machine 1 of Fig. 1 during one of a plurality of recirculation intervals of a washing cycle. The recirculation pump 12 is activated and consequently the valve 26 is opened. The recirculation pump 12 pumps the washing water from the sump or the draining suction pipe 17 to the outlet of the recirculation pipe 11 (which may have a nozzle) which is connected to the interior of the tub 2. While operating the recirculation pump 12, recirculation pipe 11 is filled with water and the water level drops from maximum level 42b to an intermediate level 42c. After the recirculation interval, i.e. after the recirculation pump 12 is deactivated or switched of, the water level rises back or almost back from the intermediate level 42c to the maximum level 42b. I.e. after switching off the recirculation pump 12, which is not perfectly watertight, the water in the recirculation pipe 11 flows back into the tub 2 as long as the valve 26 is not completely closed. Thus, after a recirculation interval, the water level in the tub 2 is high enough for washing the laundry efficiently with the water in the tub 2.

[0032] As shown in the embodiment of Fig. 4, the recirculation circuit 10 feeds the water into the tub 2 and onto the drum 4. The drum 4 comprises holes or perforations through which the washing water enters the drum 4 and wets the laundry 44. Alternatively the recirculation circuit 10 feeds the water directly into the drum 4 through an outlet at a rotational axis of the drum 4 (Fig. 7). In another embodiment the outlet of pipe 11 or nozzle is arranged at a loading door of front-loader washing machine such that the re-circulated water can be sprayed or sprinkled through the loading opening of the drum directly into the drum and the laundry 44 therein (not shown).

[0033] As indicated by Fig. 4, the activated recirculation pump 12 creates a suction force on its suction side which opens or partially opens the valve 26 due to the pressure difference acting on the ball from above and below and the ball's buoyant force. The ball 24 is moved away from its seat 22. Thereby water can be pumped from the tub 2 although the inlet 14 of the recirculation circuit 10 is placed downstream the valve seat 22. I.e. the valve 26 is automatically opened during a recirculation interval or phase of a washing cycle by the suction force of the recirculation pump 12.

[0034] Fig. 5 depicts a schematic cross sectional front view of the washing machine 1 of Fig. 1 during a draining phase of a washing cycle, i.e. when the draining pump 18 is operated. The flow of the washing water is depicted with arrows. The suction force of the draining pump 18 on its suction side opens the valve 26 and the draining pump 18 pumps water from the tub 2 and also from the recirculation circuit 10 through the draining riser pipe 19 and out of the washing machine 1. The washing water exiting the tub 2 and flowing past the filter element 28 cleans the filter element 28, i.e. washes or flushes the filter element 18, as indicated by the falling water level 42d.

[0035] The opening of the valve 26 might be prevented when the draining pump 18 is operating (Fig. 5), for example due to foam or low pressure within the tub 2 with respect to the pressure in the draining circuit 16, e.g. due to the rotation of the drum 4 during a spinning phase.

[0036] Fig. 6 depicts a schematic cross sectional front view of the washing machine 1 of Fig. 1 during a simultaneous operation of the draining pump 18 and the recirculation pump 12. The flow of water is depicted with arrows and is indicated by the falling water level 42e. As described above (Fig. 5), the draining pump 18 is operated or activated to drain washing water from the tub 2 for example during the final draining phase at the end of a washing cycle, during and/or after a spinning phase, wherein the drum rotation speed is increased to remove washing water from the laundry by centrifugal force, or during a rinsing phase, wherein the rinsing phase preferably comprises several water supply phases, spinning phases and draining phases. In particular a draining phase or period starts when the draining pump 18 starts operating or is switched-on and ends when the draining pump 18 stops operating or is switched-off. A spinning phase may comprise a draining period or phase and/or may be followed by a draining phase. For example the draining pump 18 is activated at the beginning, during and/or at the end of a drum rotation period of the spinning phase. Alternatively or additionally the draining pump 18 is activated after the end of the drum rotation period of the spinning phase.

[0037] In a washing cycle the recirculation pump 12 and the draining pump 18 are operated simultaneously for at least one time interval during at least one draining phase and/or at least one spinning phase of the washing cycle. When both pumps 12, 18 operate the suction force of both pumps 12, 18 act on the valve 26 as shown in Fig. 6 (arrows). The (short) simultaneous operation of the two pumps 12, 18 provides a steeper and/or higher pressure drop at the valve 26 in comparison to operating the draining pump 18 (or the recirculation pump) alone. Thus a pressure pulse acts on the valve 26 or ball 24, respectively, which results in a reliable and fail-safe opening of the valve 26 also under unfavourable conditions as described above.

[0038] For example the draining pump 18 is operated continuously during a draining phase an/or a spinning phase and the recirculation pump 12 is operated for at least one time interval during the continuous operation of the draining pump 18.

[0039] Preferably the draining pump 18 and the recirculation pump 12 are activated/ started at the same time for the at least one time interval to provide a steep pressure drop at the valve at the beginning of a draining phase or spinning phase. For example for at least one short time interval between 1 to 60 seconds, e.g. after the at least one time interval of simultaneous operation (to open the valve 26) the recirculation pump 12 is deactivated and the draining pump 18 remains activated to drain the washing water from the tub 2.

[0040] According to another embodiment the recirculation pump 12 and draining pump 18 are operated simultaneously for a plurality of (short) time intervals to provide a plurality of pressure impulses on the valve 26 and to build up a pressure difference at the valve 26 to open the valve 26 fail-safe. For example the draining pump 18 and the recirculation pump 12 are operated intermittently, i.e. both pumps are switched-on and -off at the same time to provide a simultaneous operation for a plurality of time intervals, wherein after the simultaneous intermittent operation of both pumps the draining pump 18 remains active to drain water from the tub 2. Alternatively the draining pump 18 operates continuously and the recirculation pump 12 is operated intermittently for said plurality of time intervals during the continuous operation of the draining pump 18.

[0041] Preferably the control unit is adapted to start operation of the recirculation pump and the draining pump after a non-operation time (pause) of the draining and recirculation pump of duration of at least 0.5, 1, 2, 3, 4 or 5 seconds. During the non-operating time a pressure equilibration to atmospheric pressure takes place in the draining circuit 16, such that the simultaneous operation of both pumps after the pause results in a steeper pressure drop at the valve 26.

[0042] As described above, the drum rotation during the spinning phase may cause a depression inside the tub 2. Preferably both pumps 12, 18 are operated simultaneously during a drum rotation period of a spinning phase to safely open the valve despite such a depression.

[0043] In the following an exemplary washing cycle is described for a washing machine according to the invention, e.g. the one described above, which is controlled by the control unit and comprises phases as described above. First a user selects and starts a washing cycle or program, respectively, preferably via a control panel (not shown). In a starting phase of the selected washing cycle water and detergent is flown into the tub 2 (Fig. 2). After this first water supply phase (Fig. 3) the drum 4 starts rotating and the recirculation pump 12 starts operating for a first of a plurality of recirculation intervals (Fig. 4), such that by spraying or sprinkling washing water on top of the laundry 44 in the tub 2 the laundry 44 is thoroughly wetted and the detergent dissolved and evenly distributed within the tub 2 and the laundry 44. During the non-operating period of the recirculation pump 12 the detergent/ washing water is distributed in the laundry by rotating the drum, preferably by repeatedly reversing the rotation direction (tumble mode).

[0044] The starting phase is followed by a heating phase, wherein a heating element within the tub 2 is operated. During the heating phase the recirculation pump 12 as well as the draining pump 18 are not operated, such that the valve 26 is closed.

[0045] After the heating phase a washing phase is executed during which the actual "washing" of the laundry is performed, i.e. the laundry is treated with the detergent or washing water at the selected temperature. For example the drum is rotated alternating in forward and backward direction to work the detergent into the laundry. During the washing phase a plurality of recirculation intervals are provided, i.e. the recirculation pump 12 is intermittently operated.

[0046] At the end of the washing phase a spinning phase is preferably executed, wherein the drum rotation speed is increased to remove washing water from the laundry by centrifugal force. During and/or after a spinning phase of the drum the draining pump 18 is activated to drain water from the tub 2, wherein the draining pump and the recirculation pump are simultaneously operated as described above. In particular the various above described operating modes for operating the draining pump and the recirculation pump simultaneously during a draining phase and/or a spinning phase can be combined in any arbitrary way for the plurality of draining and spinning phases of the washing cycle described above and below.

[0047] The washing phase is preferably followed by a rinsing phase. The rinsing phase preferably comprises several water supply phases, spinning phases and draining phases as described above. The rinsing phase starts with a water supply phase, wherein fresh water is supplied to the tub 2 to rinse the laundry, i.e. to remove detergent from the laundry. With the beginning of the (second) water supply phase the recirculation pump 12 is operated for a recirculation interval, which has a length such that the laundry is thoroughly sprinkled and soaked with the fresh water. After the recirculation interval, in particular subsequent to the end of the recirculation interval, a spinning phase which may comprise a draining phase or is followed by a draining phase as described above is advantageously executed, such that the supplied water is removed from the laundry 44 and the tub 2. Finally a last (in this example the third) water supply phase is preferably executed, wherein fresh water is supplied to the tub/ laundry and wherein the recirculation pump 12 is operated as described above. Then advantageously a last spinning and a final draining phase follows, which may comprise simultaneous operation of both pumps as described above. Thereafter the washing cycle is finished and the laundry ready to take out of the washing machine or ready for further treatment, e.g. for drying in the washing machine, in case the washing machine has a dryer function.

[0048] Fig. 7 depicts a perspective, partially cross-sectional side view of a part of an exemplary internal structure of a washing machine 1 as schematically depicted in Fig. 1, which in this embodiment is a top-loading washing machine. The same reference signs are used for the same features of the washing machine 1 as described above. Relating to technical details and functional operation, full reference is made to the above embodiment schematically shown. The drum 4 is rotationally supported in the tub 2. Below the tub 2 the valve 26 is shown in a partial cross-sectional view. The ball 24 is engaged in the valve seat 22 and shuts the tub 2 from the draining circuit 16 in the state as depicted. The inlet 14 of the recirculation circuit 10 is advantageously located below the valve 26, in particular below the valve seat 22. The suction side of the recirculation pump 12 is connected via suction pipe 13 to the sump or draining suction pipe 17. The output side of the pump 12 is connected via recirculation pipe 11 to a passage through and having an outlet at a rotational axis of the drum 4. The draining circuit 16 is fluidly connected to the tub 2 through the opening in the ball valve seat 22 (having the form of a diaphragm or plate) such that washing water can be drained from the tub 2 through pipe 17, draining filter 20, pump 18 and draining riser pipe 19 to the outside of the machine with the draining pump 18 operating.

[0049] Fig. 8 shows a perspective, partially cross-sectional side view of the structure of Fig. 7. In this partial cross-sectional view, the filter element 28 can be seen, which is arranged at the inlet 14 of the recirculation circuit 10. Fig. 9 shows a partial cross-sectional top view of a detail of the structure of Fig. 7. The diaphragm or plate of the valve seat 22 is attached at the lower rim of an extension of the tub 2, extending at the bottom of the tub 2. The valve body 27 receiving the ball 24 is attached to the tub extension at the diaphragm and is forming part of the draining suction pipe 17. Both the suction pipe 13 and the draining suction pipe 17 have sections formed as a bellows. The bellows serve for damping vibrations of the tub 2 from being transferred to the pumps 12, 18.

[0050] Figs. 10a-d depict perspective, cross sectional views of the valve 26 as shown in Fig. 7.

[0051] Fig. 10a shows a top view of the valve 26, wherein the diaphragm forming the valve seat 22 is shown from the tub side. A lug 29 is advantageously attached to and protruding from the valve body 27 which is used to attach one end of the suction pipe 13. The filter element 28 is attached to the lug 29; preferably the filter element 28 is made as a single or monolithic part with the lug 29. The lug 29 is used to mount the filter element 28 at an outlet in the valve body 27, wherein the outlet forms the inlet 14 to the suction circuit 10.

[0052] A further opening 37 in the valve body 27 fluidly connects the interior of the valve body 27 to a duct 36 depicted in Fig. 10a-d. The duct 36 is connected to a pressure control (pressostat; not shown) for detecting the water level 42 in the tub 2.

[0053] Fig. 10b shows a cross sectional view of the valve 26 along line A-A of Fig. 10a. The valve 26 is shut or closed by ball 24 which rests in its seat 22 and blocks thereby the opening in the valve 26. The filter element 28 is attached to the inlet 14 of the recirculation circuit 10 by the mounting portion or lug 29 which is connected to the recirculation circuit 10 by a plug connection. In particular the filter element 28 is attached to the lug 29 forming the inlet 14 in a cantilevered manner, such that the main body of the filter element 28 extends into inner volume of the valve body 27 in a free-standing manner. A portion of the filter element 28 facing the inner space of the valve body 27 comprises a bent shape which corresponds or basically corresponds to the shape of the ball 24.

[0054] Fig. 10d shows a cross sectional view from below along the line B-B shown in Fig. 10c. The filter element 28 has a fork-like shape with fingers and apertures between the fingers. The fingers of the filter form the teeth or pins of a rake. The fingers are parallel or essentially parallel to a flow path of water flowing from the tub 2 through the valve body 27 to the draining pump 18 in draining phases.

[0055] Fig. 11 shows a cross-sectional side view of the ball valve of Figs. 10a-d in a closed state, which has been described with respect to Fig. 3. The outer surface of the filter element 28 faces a portion of the inner surface of the valve body 27 and the filter element 28 is arranged such that there is a gap 33 between the outer or lower surface 32 of the filter element and the inner surface of the valve body. The water filling the tub 2, the draining circuit 16 and partially the recirculation circuit 10 results in a buoyant force on the floatable ball 24, which presses the ball 24 against the valve seat 22 (both pumps 12, 18 are not operating).

[0056] Fig. 12 shows a cross-sectional side view of the ball valve of Figs. 10a-d in an opened state, which has been described with respect to Figs. 2, 4, 5 and 6. Due to a low water level 42a (Fig. 2) or due to the suction force of the recirculation pump 12 (Fig. 4) or the suction force of the draining pump 18 alone (Fig. 5) or the suction force of both pumps 12, 18 (Fig. 6) the valve 26 is opened. The ball 24 is in close proximity to the filter element 28 or is supported by the filter element, which comprises a curved shape which matches or substantially matches the shape of the ball 24. According to another embodiment no filter element is provided, wherein for example the valve body 27 is formed or shaped such that the ball 24 is supported by the valve body 27 when the valve 26 is open.

Claims

1. Washing machine (1) comprising:

a control unit adapted to control the washing machine to perform at least one washing cycle,

a tub (2),

a rotatable drum (4) within the tub (2),

a draining circuit (16), wherein the draining circuit (16) is fluidly connected to a lower portion of the tub (2) and wherein the draining circuit (16) comprises a draining pump (18) for draining fluid from the tub (2),

a valve (26) arranged between the tub (2) and the draining circuit (16),

a recirculation circuit (10) fluidly connected to the tub (2), wherein an inlet (14) of the recirculation circuit (10) is positioned downstream a valve seat (22) of the valve (26), and wherein the recirculation circuit comprises a recirculation pump (12) for re-circulating fluid from the lower portion of the tub (2) into the tub (2), and

wherein said valve (26) is adapted to be opened when the recirculation pump (12) is operated and is adapted to be closed when the recirculation pump (12) is not operated,

characterized in that

said control unit is adapted to operate said recirculation pump (12) and said draining pump (18) simultaneously for at least one time interval during at least one draining phase and/or during at least one spinning phase of the washing cycle.

2. Washing machine according to claim 1, wherein at least one of said time intervals is at least 0.3, 0.4, 0.5, 0.8, 1, 2, 3, 4, 5, 10, 20, 40 or 60 seconds.

3. Washing machine according to claim 1 or 2, wherein at least one of said time intervals is shorter than 2, 4, 8, 10, 20, 30, 40 or 60 seconds.

4. Washing machine according to claim 1, 2 or 3, wherein the control unit is adapted to operate said recirculation pump (12) and said draining pump (18) simultaneously for a plurality of or repeatedly for said time intervals.

5. Washing machine according to any of the previous claims, wherein the control unit is adapted to start operation of the recirculation pump (12) and the draining pump (18) simultaneously.

6. Washing machine according to any of the previous claims, wherein the control unit is adapted to start operation of the recirculation pump (12) and the draining pump (18) simultaneously after a non-operation time of the draining and recirculation pump of duration of at least 0.5, 1, 2, 3, 4 or 5 seconds.

7. Washing machine according to any of the previous claims, wherein the draining pump (18) and/or the recirculation pump (12) is executing a series of at least two start/stop intervals

8. Washing machine according to any of the previous claims, wherein the control unit is adapted to operate said recirculation pump (12) and said draining pump (18) simultaneously at the beginning of at least one of the draining phases.

9. Washing machine according to any of the previous claims, wherein the control unit is adapted to operate said recirculation pump (12) and said draining pump (18) simultaneously during a drum rotation period of at least one of said spinning phases.

10. Washing machine according to any of the previous claims, wherein the control unit is adapted to operate said recirculation pump (12) and said draining pump (18) simultaneously at the end of at least one of said spinning phases or at least at the final spinning phase.

11. Method of operating a washing machine, in particular a washing machine according to any of the previous claims,
wherein the washing machine (1) comprises:

a valve (26) arranged at a bottom region of a tub (2),

a draining circuit (16)) comprising a draining pump (18) for draining fluid from the tub (2), wherein the draining circuit (16) is fluidly connected to a lower portion of the tub (2),

a recirculation circuit (10) comprising a recirculation pump (12) for recirculating water, wherein an inlet (14) of the recirculation circuit is connected to a valve body (27) of the valve, the inlet being arranged below a valve seat (22) of the valve, and

a control unit adapted to control at least one washing cycle of the washing machine,

wherein the valve (26) is adapted to be opened when the recirculation pump (12) is operated and is adapted to be closed when the recirculation pump (12) is not operated;

the method comprising:

activating/operating the recirculation pump (12) and the draining pump (18) simultaneously for at least one time interval during at least one draining phase and/or at least one spinning phase of the at least one washing cycle.

12. Method according to claim 11, wherein at least one of said time intervals is at least 0.3, 0.4, 0.5, 0.8, 1, 2, 3, 4, 5, 10, 20, 40 or 60 seconds.

13. Method according to claim 11 or 12, wherein at least one of said time intervals is shorter than 2, 4, 8, 10, 20, 30, 40 or 60 seconds.

14. Method according to claim 11, 12 or 13, comprising operating the recirculation pump (12) and the draining pump (18) simultaneously at the beginning of at least one of the draining phases.

15. Method according to any of claims 11 to 14, comprising operating the recirculation pump (12) and the draining pump (18) simultaneously after a non-operation time of the draining pump and recirculation pump of duration of at least 0.5, 1, 2, 3, 4 or 5 seconds.

Drawing