EP2246469B1 - Method for operating a washing machine and washing machine with circulation pump and spinning phase - Google Patents

Description

Field of the invention

The invention relates to a washing machine and a method for operating a washing machine according to the preamble of the independent claims.

background

Washing machines are usually equipped with a rotatable drum for holding laundry. This is arranged in a watertight tub.

It's off, for example EP 1 386 996 known to design washing machines with a circulation pump to promote water from the bottom portion of the tub via a circulation line and a nozzle in the ceiling region of the tub. Such arrangements allow a more uniform wetting of the laundry.

Also the document EP 0 224 776 A2 , which is considered to be the closest prior art, discloses the use of a circulation pump in a washing machine.

To wash laundry, the drum is at least temporarily rotated at a predetermined speed in a wash cycle. This can increase the washing performance.

Presentation of the invention

Object of the present invention is to provide a way to reduce the water and energy consumption of a washing machine.

This object is solved by the subject matter of the independent claims.

According to the claim, the drum, as in known solutions, is rotated at least temporarily in the wash cycle at a first speed. In the wash cycle now at least one spin phase is provided while rotating the drum at a second speed, which is higher than the first speed, to drive water out of the laundry and into the drainage area of the drum. Thus, thanks to the centrifugal forces acting water is expressed from the laundry, which increases the amount of water in the drain area. In order to return the expelled water to the laundry, the circulation pump is put into operation.

• Zum einen wird die Waschwirkung erhöht und/oder die Waschzeit reduziert, d.h. die Waschleistung wird verbessert, da durch die Schleuderphase der Wasseraustausch an der Oberfläche und im Innern der Wäsche gegenüber einem konventionellen Verfahren verbessert wird.
• Zum anderen ermöglicht das Vorgehen eine Reduktion der benötigten Wassermenge. Bei konventionellen Geräten muss so viel Wasser in die Maschine eingefüllt werden, dass, selbst wenn die Wäsche mit Wasser vollgesogen ist, eine ausreichende Wassermenge im Ablaufbereich und/oder der Zirkulationsleitung vorhanden ist, um die dort angeordnete Heizung zu überdecken. Dank der Schleuderphase kann der Wasserpegel im Ablaufbereich gezielt nur dann erhöht werden, wenn dort viel Wasser benötigt wird. Das hierzu benötigte Wasser wird der Wäsche entzogen.

This procedure achieves two effects:

• On the one hand, the washing action is increased and / or the washing time is reduced, ie the washing performance is improved because the spin phase improves the water exchange on the surface and inside the laundry compared to a conventional process.
• On the other hand, the procedure allows a reduction of the required amount of water. Conventional equipment requires so much water to be poured into the machine that, even if the laundry is soaked with water, there is sufficient water in the drain and / or circulation line to cover the heater located there. Thanks to the spin phase, the water level in the drain area can only be specifically increased if a lot of water is needed there. The water required for this purpose is removed from the laundry.

According to the claim, a heater is arranged in the discharge area, in the circulation pump and / or in the circulation line. For heating the water in the tub, the water level in the drainage area is initially increased by means of the spin phase and then the heating is switched on. As a result, the water level is increased when more water in the drain area and / or circulation system is required for heating.

Preferably, for at least one cleaning phase, the amount of water supplied is such that if the laundry is saturated with water, there will not be enough water in the tub, pump and circulation line without prior spin to circulate the water and / or circulate the water through the circulation pump. By this measure, the amount of water can be further reduced.

According to the claim, at the latest after heating, the water is circulated via the circulation pump, whereby at least a part of the water is bound back into the laundry, i. is retained by the laundry, e.g. by capillary forces or in folds and the like of the laundry. This reduces the water level in the drainage area. The water level sinks to the point where it drops below the top of the heater. This is not possible with a conventional washing machine, since it must be ensured that the heating is always covered with water.

Further, for at least one cleaning phase, the amount of water supplied is such that when the laundry is saturated with water, without a preceding spin phase, the bottom of the drum is above the water level of the water lying in the bottom area of the drum. In other words, in this case, the drum does not dip into the water in the tub. By this measure, friction losses when rotating the drum, e.g. in the context of a conventional reversing process, reduced.

Only when more water is needed again for pumping or heating, a spin phase can be inserted so that the amount of water in the drain area or in the circulation pump and the circulation line increases again.

The invention also makes it possible to reduce the consumption of detergent by also less detergent is needed to achieve the same detergent concentration thanks to the reduced amount of water.

The invention can be formulated as a method, but also as a washing machine, whose control is designed to carry out such a method. In particular, the claims may be formulated both as device claims and as method claims.

Brief description of the drawings

• Fig. 1 einen schematischen Schnitt durch die relevanten Komponenten einer Waschmaschine und
• Fig. 2 den Schnitt nach Fig. 1 mit Wäsche in der Trommel und mit Beispielen für den Wasserpegel während der einzelnen Betriebsphasen.

Further embodiments, advantages and applications of the invention will become apparent from the dependent claims and from the following description with reference to FIGS. Showing:

• Fig. 1 a schematic section through the relevant components of a washing machine and
• Fig. 2 the cut after Fig. 1 with laundry in the drum and with examples of the water level during the individual phases of operation.

Ways to carry out the invention Design of the washing machine

The washing machine after Fig. 1 has a substantially cylindrical drum 1 for receiving the laundry. The drum 1 is arranged in a tub 2 (tub), which is also substantially cylindrical. The drum can be driven for rotation, in the present example about a horizontal axis of rotation. The tub is stationary. To take along the laundry can be arranged on the inside of the drum in a known manner driver 4. The shell surface of the drum is preferably perforated so that water can pass through it while the walls of the tub are watertight.

The term "water" is to be understood as the wash liquor used to wash the laundry.

At the bottom of the tub 2, a drain region 6 is provided, which forms the lowest point of the tub and in which the water accumulates. From the drainage area, the water can be discharged on the one hand via a drain pump 7 from the washing machine, and on the other hand via a circulation pump 8 and a circulation line 9 back into a ceiling region 10 of the tub. The term "ceiling area" is to be understood broadly and denotes an area in the upper half of the tub 2. The exact location of the mouth of the circulation line is in the present context only of minor importance. It can also be provided several mouths at different locations. It is important that the water in the drum can be well wetted with the water leaving the orifices. An example of a suitable injector is in EP 1 700 943 disclosed. When using a drum 1 with a horizontal axis of rotation, which is open towards the door, the water is preferably injected from the door into the drum 1.

How out Fig. 1 further seen, a heater 12 is provided in the drain area 6. This may be, for example, an electrical resistance heater. However, it is also conceivable that the heater is at least partially formed by the condenser of a heat pump.

Alternatively or in addition to the arrangement of the heater 12 in the drain region 6, the heater can also be arranged in the circulation pump 8 and / or in the circulation line 9.

Furthermore, the device comprises a controller 14, which is designed to control the device with the method steps described below.

washing method

Before beginning a wash cycle, the laundry 15, as in Fig. 2 represented, filled in the drum 1.

Then, water is introduced into the tub 2 via an unillustrated water supply system. Preferably, this is done so that the laundry is irrigated directly with the entering into the tub 2 water. However, it is also conceivable that the water is introduced somewhere in the tub 2 and passes through the drainage area 6 to the circulation pump 8. The circulation pump 8 is put into operation to irrigate the laundry via the circulation pump 9.

In this way, water is introduced into the laundry. At the same time, the drum 1 is rotated continuously or at intervals at a first, low speed, e.g. by reversing, to mix the laundry and wet on all sides. The laundry, as mentioned above, takes on a large amount of water. The water is more or less strongly bound in the fibers, on the surface and in folds or the like, i. it is prevented from spontaneous or at least rapid drainage from the laundry.

The amount of water that is supplied to the tub or the laundry is preferably such that it is normally insufficient for an operation of the heater 12 and / or the circulation pump 8, namely as long as the laundry is saturated with water and the drum 1 only is rotated at the first low speed. In particular, the heater 12 in this state is not (or at least not completely) covered by water and / or the pump 8 would suck in air when pumping. For example, the water level in the drainage area lies on the in Fig. 2 under reference numeral 17.

Now, if the heater 12 and / or the circulation pump 8 are put into operation, a spin phase is first carried out. During this spin phase The drum is rotated at a second, higher speed at which a larger amount of water is expelled by centrifugal forces from the laundry. As a result, the water level in the drain area 6 increases so much that the heater 12 is completely covered and / or proper operation of the circulation pump is ensured. For example, the water level reaches the in Fig. 2 height shown under reference number 18.

Advantageously, the first speed of the drum is less than 55 revolutions per minute, e.g. 30, while the second speed is between 60 and 120, in particular 80, revolutions per minute. The second speed should be such that the amount of water bound by the laundry is at least a few liters less than when turning at the first speed. At the same time, the second speed should not be too high, so that delicate laundry is spared and unbalance problems on the drum can be avoided.

Once the water level in the drainage area 6 has risen sufficiently, the heater 12 can be put into operation to heat the water. In addition, the circulation pump 8 can be operated.

For example, to monitor the water level in the drainage area, a water level detector 19 may be provided which signals when the water level has reached a level sufficient to permit heating and / or pumping. The water level detector 19 can be designed, for example, as a pressure sensor, so that a plurality of different water levels can be distinguished from one another. In particular, it is advantageous if it can be detected with the water level detector 19 whether the water level is below a first, lower altitude 17 or whether the water level is above a second, higher altitude 18

1. 1) Zunächst wird eine vordefinierte Menge Frischwasser eingefüllt. Hierzu sind Zuführmittel vorgesehen, welche von der Steuerung 14 entsprechend gesteuert werden können. Die Trommel wird dabei mit der ersten, tieferen Geschwindigkeit rotiert. Die Wäsche wird benetzt.
2. 2) Nun wird eine Schleuderphase mit der zweiten, höheren Geschwindigkeit durchgeführt und es wird mit dem Wasserpegeldetektor gemessen, ob das Wasser innert vorgegebener Zeit von z.B. einer Minute den Wasserpegel 18 erreicht hat. Erreicht das Wasser z.B. aufgrund hoher Beladung der Trommel mit sehr saugfähiger Wäsche den Wasserpegel 18 nicht, so wird zusätzlich Frischwasser zugegeben, bis der Wasserpegel 18 erreicht wird.
3. 3) Ist der Wasserpegel 18 erreicht, wird die Heizung 12 in Betrieb gesetzt. Nun kann in unterschiedlicher Weise weitergefahren werden, siehe folgende Varianten 3a, 3b, 3c:
   • 3a) Die Zirkulationspumpe 8 bleibt noch abgeschaltet, bis das Wasser eine gewisse Temperatur erreicht hat, und gleichzeitig kann die Trommel 1 wieder mit der ersten, langsameren Geschwindigkeit gedreht (oder gar nicht gedreht) werden. Wenn das Wasser eine vorgegebene Temperatur erreicht hat, wird die Heizung abgeschaltet. Die Zirkulationspumpe 8 wird in Betrieb genommen und fördert wieder Wasser in die Wäsche. Dadurch sinkt der Wasserpegel im Ablaufbereich 6 z.B. wieder auf den Pegel 17 ab. Dies kann z.B. mit dem Wasserpegeldetektor 19 festgestellt werden. Dann wird die Pumpe wieder abgeschaltet. Der Wasserpegeldetektor 19 kann zu diesem Zweck auch von einem "Schnorcheldetektor" gebildet werden, welcher anzeigt, ob die Zirkulationspumpe 8 Luft ansaugt.
   • 3b) Die Zirkulationspumpe 8 wird eingeschaltet, während die Heizung 12 noch in Betrieb ist. Dadurch kann das Wasser während dem Heizen bewegt werden. In diesem Fall wird das Wasser über die Zirkulationsleitung 9 in die Wäsche gefördert. Damit nun der Wasserpegel nicht bis zur Höhe der Heizung 12 absinkt, muss gleichzeitig die Trommel weiter mit der zweiten, höheren Geschwindigkeit betrieben werden.
   • 3c) Die Zirkulationspumpe 8 wird eingeschaltet, während die Heizung 12 noch in Betrieb ist, die Waschmaschine ist jedoch so ausgestaltet, dass das Wasser von der Zirkulationspumpe 8 wahlweise in die Trommel 1 oder unter Umgehung der Trommel 1 wieder direkt zurück in den Ablaufbereich 6 gefördert werden kann. Hierzu kann beispielsweise in der Zirkulationsleitung 9 ein Umschaltventil 22 vorgesehen sein, mit welchem das Wasser von der Zirkulationspumpe 8 entweder in den Deckenbereich des Bottichs 1 oder ohne Berührung der Trommel 1 wieder zurück in den Ablaufbereich 6 gefördert werden kann.

Specifically, a wash may look like this, for example:

1. 1) First, a predefined amount of fresh water is filled. For this purpose, supply means are provided, which can be controlled by the controller 14 accordingly. The drum is rotated at the first, lower speed. The laundry is moistened.
2. 2) Now, a spin phase is carried out at the second, higher speed and it is measured with the water level detector, if the water within a predetermined time of eg one minute has reached the water level 18. If, for example, the water does not reach the water level 18 due to high loading of the drum with very absorbent laundry, fresh water is additionally added until the water level 18 is reached.
3. 3) When the water level reaches 18, the heater 12 is put into operation. Now you can proceed in different ways, see following variants 3a, 3b, 3c:
   • 3a) The circulation pump 8 remains switched off until the water has reached a certain temperature, and at the same time the drum 1 can again be rotated (or not rotated) at the first, slower speed. When the water has reached a predetermined temperature, the heating is switched off. The circulation pump 8 is put into operation and again promotes water in the laundry. As a result, the water level in the drain region 6 drops, for example, back to the level 17. This can be determined, for example, with the water level detector 19. Then the pump is switched off again. The water level detector 19 can be formed for this purpose by a "snorkel detector", which indicates whether the circulation pump 8 sucks air.
   • 3b) The circulation pump 8 is turned on while the heater 12 is still operating. This allows the water to be moved while heating. In this Case, the water is conveyed through the circulation line 9 in the laundry. So that now the water level does not drop to the height of the heater 12, at the same time the drum must continue to be operated at the second, higher speed.
   • 3 c) The circulation pump 8 is switched on while the heater 12 is still in operation, but the washing machine is designed such that the water from the circulation pump 8 is conveyed directly into the drum 1 or bypassing the drum 1 directly back into the drainage area 6 can be. For this purpose, for example in the circulation line 9, a switching valve 22 may be provided, with which the water from the circulation pump 8 either in the ceiling region of the tub 1 or without touching the drum 1 back into the drain area 6 can be promoted.

If necessary, the cycles 2) and 3) can be repeated, with or without putting the heater 12. As mentioned above, a Zwischenschleuderphase can be useful even if not heated, since the spin phase of the water exchange on the surface and inside the laundry is improved.

After completion of the cleaning, the water is drained by the drain pump 7 is put into operation. In order to drive the water out of the laundry, the laundry can be thrown again. Thereafter, optionally, the laundry may be e.g. be rinsed again with fresh water, after which also the rinse water is pumped out. The method may be terminated, as far as the user so wishes, with a high speed spinning phase (e.g., at several hundred revolutions per minute).

Remarks

As mentioned above, the bottom of the drum 1, at least when the laundry is saturated with water is, advantageously above the tub water level. This reduces friction losses.

If a spin phase is performed, the water level rises. Preferably, however, it is then even below the bottom of the drum, so that the friction losses remain small.

The spin phase is preferably performed until the water level in the drain area rises above an upper limit (e.g., altitude 18).

The water is led back from the drainage area 12 with the circulation pump 8 and the circulation line 9 directly back into the tub 1, i. without intermediate storage of the water in an intermediate tank or the like, where the water would rest again, so that standing in the circulation system, unused amount of water is as small as possible.

The invention makes it possible to reduce the required amount of water and thus also the required heating energy significantly. If a conventional machine needs 8 kg of laundry, e.g. 20 liters of water, this amount can be reduced by the measures described above to e.g. 16 liters are reduced.

While preferred embodiments of the invention are described in the present application, it is to be understood that the invention is not limited thereto and may be embodied otherwise within the scope of the following claims.

Claims (12)

1. A method for operating a washing machine, wherein the washing machine comprises
   a rotatable drum (1) for acceptance of laundry,
   a tub (2) in which the drum (1) is arranged,
   a circulation pump (8) for circulating water from a drainage area (6) of the tub (2) through a circulation pipe (9) back into the tub (2),
   wherein in a wash cycle the drum (1) is rotated at least temporarily with a first speed,
   and in the wash cycle the drum (1) is in a spin phase rotated at a second speed which is higher than the first speed to expel water from the laundry and bring it into the drainage area (6),
   and the circulation pump (8) is put into operation to deliver expelled water through the circulation pipe (9) back to the laundry,
   characterized in that a heater (12) is arranged in the drainage area (6), near the circulation pump (8), and/or near the circulation pipe (9),
   wherein prior to heating the water, a water level in the drainage area (6) is increased by means of the spin phase and then the heater (12) is turned on, and wherein the water level is increased until then at least the heater (12) is covered by water,
   and wherein after the heating at the latest, the water is circulated via the circulation pump (8) and at least a part of the water is thus again bound in the laundry such that the water level in the drainage area (6) decreases at least below the top side of the heater (12).
2. The method of claim 1, wherein a supplied amount of water is dimensioned such that when the laundry is saturated with water, without a prior spin phase not enough water is present for heating the water and/or for circulating the water via the circulation pump (8).
3. The method of any of the preceding claims, wherein a supplied amount of water is dimensioned such that when the laundry is saturated with water, at least without a prior spin phase a bottom side of the drum (1) always lies above a water level of the water in the tub (2).
4. The method of any of the preceding claims, wherein a rotation speed of the tub (1) at the second speed is between 60 und 120 revolutions per minute, in particular at approximately 80 revolutions per minute,
   and wherein a rotation speed of the drum (1) at the first speed is less than 55 revolutions per minute.
5. The method of any of the preceding claims, wherein the water is delivered by the circulation pump (8) through the circulation pipe (9) into a ceiling zone (10) of the tub (2),
   and in particular wherein the tub (1) has a horizontal rotation axis and is open towards a door and the water is sprayed into the drum (1) directed from the door.
6. The method of any of the preceding claims, wherein in the drainage area (6) the water level is measured und wherein the spin phase is conducted until then the water level in the drainage area increases above an upper limit.
7. The method of any of the preceding claims, wherein in the drainage area (6) the water level is measured and wherein the circulation pump (8) is turned off when the water level in the drainage area (6) decreases below a lower limit.
8. A washing machine for carrying out the method of any of the preceding claims comprising
   a rotatable drum (1) for acceptance of laundry,
   a tub (2) in which the drum (1) is arranged,
   a circulation pump (8) for circulating water from a drainage area (6) of the tub (2) through a circulation pipe (9) back into the tub (2),
   a heater (12) in the drainage area (6), near the circulation pump (8) and/or near the circulation pipe (9), and
   a control unit (14) which is structured to carry out the method of any of the preceding claims.
9. The washing machine of claim 8, wherein the circulation pipe (9) ends in a ceiling zone of the tub (2).
10. The washing machine of any of the claims 8 or 9, wherein at least one water level detector (19) is arranged in the drainage area (6), and in particular wherein it is detectable by means of the water level detector (19) whether the water level is below a first, lower level or whether the water level is above a second, higher level.
11. The washing machine of any of the claims 8 to 10, wherein it is structured such that the water from the circulation pump (8) is selectively deliverable into the drum (1) or bypassing the drum 1 back into the drainage area (6) of the tub (2).
12. The washing machine of any of the claims 8 to 11, wherein the water is guidable via the circulation pump (8) and the circulation pipe (9) directly into the tub (2) without intermediate storage of the water.

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