EP2592182A1 - Washing machine with reduced remoistening and method for its operation - Google Patents

Abstract

The washing machine has program controller, water supply system, and a driving motor for the drum (2). The screw-like structures (16,17,22,23) are formed on surface of the drum (28) and/or a lateral tub wall (27) in a state projecting into an intermediate space (26) between the drum and the washing container (1), for generating axial air flow upon rotation of the drum about a horizontal rotary axis (3) in the direction of a rear tub wall (24). An independent claim is included for method for operating washing machine.

Description

The invention relates to a washing machine with reduced rewetting and a preferred method for its operation. In particular, the invention relates to a washing machine for the treatment of laundry with a program control, a water supply system, a rotatably mounted drum in a tub and a drive motor for the drum, wherein structures on the drum and / or in the tub influence the air flow, and a particularly suitable method to operate this washing machine.

A washing program generally has a rinsing phase with several spinning steps after a wetting phase and a washing phase. With a last spin step, as much water as possible should be removed from the wash, so that the washed laundry, which may have been treated with a fabric softener, does not have to be taken out dripping wet. In particular, it is desirable that the residual moisture still present in the laundry after the spin phase is as low as possible. This is generally achieved by a good separation of the water when spinning at a high speed of the drum. In this case, the centrifugal force forces the water from the laundry through drainage holes of the drum to the outside into a space between the drum and the tub, where it ideally flows into a lower part of the tub, a region comprising a heater, also referred to as a "heater bag" , From the radiator pocket, this water can then be pumped out for disposal or reuse.

The removal of thrown-off water, however, is influenced by the flow of air due to the rotation of the drum. In general, during the rotational movement of the drum, an air flow with a velocity gradient arises in the space between the drum and the tub, wherein the air layer applied directly to the outside of the drum substantially takes over the peripheral speed of the drum. For example, with a drum of 50 cm diameter, the corresponding peripheral speed at a spin speed of 1400 revolutions per minute is 2200 m / min or 130 km / h. In contrast, the Flow rate of the air layer directly adjacent to the tub wall 0 km / h. Thus, there is a velocity gradient of the air flow in the space between the moving drum and the non-moving tub, but not necessarily linear. Water droplets are drawn perpendicular to the flow following the velocity gradient into the air flow (Bernoulli or Venturi effect).

The drum thus gives due to their rapid rotation of the amount of air, which is located in the space between the drum and tub, a tangential pulse in the direction of rotation of the drum. As the water exiting through the perforated drum also leaves the drum in the tangential direction, i. In tangential direction, there is an additional, dependent on the actual water flow contribution to the tangential pulse. As a result, a circular circulation of the amount of air is obtained in the space between the drum and tub, which affects a forming on the inner wall of the tub water ring. Specifically, a certain amount of water, instead of being landed in the radiator pocket for pumping, is circulated on the inside of the tub (also referred to herein as the "side tub wall") as a so-called water ring. Known measures for deriving this water ring and thus to reduce the re-wetting are introduced into the tub form elements.

In addition, usually caused by the rotational movement of the drum, an air pressure difference, in particular between the interior of the drum, where a low air pressure prevails (negative pressure), and the space between the drum and tub, which has a higher air pressure (pressure). This pressure difference seeks ways to compensate, with the drum gap between the drum and a door closing this to the surrounding space has the largest possible cross-section and thus the lowest resistance for pressure equalization. This results in the compensation of the pressure difference in the space a second, directed towards the closing door radial flow component.

Both flow components, the radial flow resulting from pressure differences and the tangential circulating flow, are superimposed to form a toroidal air flow which is screwed approximately in the direction of drum rotation.

This air flow entrains water droplets, for example from the surface of the water ring, so that the water ring is more like a wild spray than a compact amount of water and thus has a correspondingly large surface area. In addition, water droplets are in particular entrained from the water in the radiator bag. This effect is more pronounced when due to uneven, i. unbalanced, rotation of the drum, which may arise, for example, by an uneven distribution of the laundry in the drum, water droplets are thrown from the radiator pocket.

In general, the water droplets are drawn perpendicular to the air flow according to the velocity gradient in the flow (Bernoulli or Venturi effect) and thereby entrained in the longitudinal direction with the flow.

The water droplets entrained with the air flow can in particular pass back to the laundry via the drum gap and thus bring about rewetting of the laundry, which thus has an increased residual moisture content. In order to remove this residual moisture still a disproportionate time and energy-consuming spin would be required, especially as the amount of water still in the system is progressively withdrawn slowly as the spin progresses.

To counteract a rewet, is from the DE 24 48 834 A1 discloses a method for spinning in a washing machine, wherein during the spinning repeatedly between a low and a high speed of the drum is switched to avoid the emergence of a water ring in the form of entrained by the drum water. However, the spin process is prolonged because it is thrown repeatedly at low speed.

The EP 1 050 616 A1 describes a method for spinning in a washing machine, in which the reduction of the speed ("Abtouren") after the spin is not carried out with high negative acceleration, but the steepness of the Abtourrampe is reduced, to avoid that the water ring coincides during Abtouren and dripping on the drum. A rewetting by the amount of water during the Skidding passes through the described air flow over the drum gap on the laundry, this is not avoided.

The DE 197 52 512 A1 describes a washing machine with a washing tub rotatably arranged in a tub around a horizontal axis, wherein in the washing drum shell outwardly or inwardly directed formations are present.

The DE 10 2005 026 175 A1 describes a water-leading household appliance, such as a washing machine, with a rotatably mounted laundry drum with a drum shell and at least one drum top surface, wherein imprints are applied to the laundry drum, wherein the edges of the embossments are formed elliptical.

From the DE 44 45 669 A1 a washing drum for a washing machine is known, which is provided via a cylindrical shell with a plurality of holes for the passage of working fluid. Between these holes trough-like characteristics or elevations are provided.

Finally, that describes DE 196 03 710 A1 a washer-dryer or a drum washing machine with a tub and a washing drum rotatably arranged in the tub, wherein the jacket of the tub is provided with embossments which are round, oval or polygonal. Here round embossments have a slightly curved shape.

The DE 102 05 306 A1 describes a drum washing machine with a laundry drum whose shell is perforated, and which is surrounded by a container within which it is mounted on its rear wall at least horizontally flying, and with a working section for spin-drying the laundry located in the drum. In this drum type washing machine, provision is made for substantially no air to flow from the container through the interior of the drum and back to the container during spin-drying. A precaution, for example, is a barrier disposed in the annular gap between the charging opening of the drum and the front opening of the container. In addition, another measure is that the drum shell on a ring section, which is attached to the rear wall of the drum adjoins, at least a smaller specific hole area portion than on the closer to the feed opening arranged ring section.

The DE 20 2009 000 376 U1 describes a washing drum for a washing machine, the cylindrical shell has a plurality of flow holes and attached to the outer side of the washing drum compression space paddles. When spinning after the rinse and pumping out the rinsing liquid, the blades generate a negative pressure due to their wedge shape, so that the moisture in the laundry is exposed not only to the centrifugal forces but also this negative pressure.

Against this background, the object of the present invention was to provide a washing machine in which the treated laundry has a reduced residual moisture after spinning. In addition, the invention has for its object to provide a method for operating this washing machine.

The solution of this object is achieved according to this invention by a washing machine for the treatment of laundry and by a method for operating a washing machine having the features of the corresponding independent claim. Preferred embodiments of the washing machine according to the invention and of the method according to the invention are listed in corresponding dependent claims and the following description and attached drawing. Preferred embodiments of the washing machine according to the invention correspond to preferred embodiments of the method according to the invention and vice versa, even if this is not explicitly stated herein.

The invention thus relates to a washing machine for the treatment of laundry with a program control, a water supply system, a rotatably mounted drum in a tub and a drive motor for the drum wherein on a drum surface and / or a side tub wall in a space between the drum and the tub outwardly projecting structures are arranged, which generate upon rotation of the drum about a substantially horizontal axis of rotation directed towards a rear suds container wall axial air flow.

Here, the term "generating a directed toward a rear tub wall airflow" is interpreted broadly and includes in particular directed towards a rear tub wall axial airflow component, which counteracts a usually directed forward to the door of the washing machine axial air flow component. Depending on the size of these components, either a reduced axial flow in the direction of the door is obtained, a quiescent state when both components cancel, or an axial air flow directed towards the rear suds container wall. Preferably, no axial air flow occurs in the direction of the door of the washing machine more.

A "compensation speed" is a speed of the drum, in which both components cancel, so that in the axial direction no air flow occurs.

"Outstanding structures" in the context of the invention are generally those which protrude from the surface of the drum or the lateral tub wall in an intermediate space between the drum and the tub.

To achieve this effect, it is preferred that the protruding structures form a helical structure.

In a preferred embodiment of the washing machine, the protruding structures are lamellas, in particular helically arranged lamellae. The term "fin" herein generally refers to thin, long slices or leaves which may be flat or tortuous.

According to the invention it is preferred that the protruding structures are regularly arranged in a ring around the drum surface. In this case, according to the invention, a plurality of rings of protruding structures can be used. In the case of a ring arranged on the drum surface closer to the door of the washing machine, the protruding structures, eg lamellas, are preferably larger or provided with a greater pitch of the structures than in a rear area of the drum surface.

Moreover, it is preferable that the protruding structures are disposed in a front half of the drum surface and / or a front half of the side tub wall.

The arrangement is advantageous both on the drum and on the tub. In a preferred embodiment of the invention, therefore, lamellas are arranged on the drum surface and on the lateral tub wall as outwardly projecting structures. In this case, the lamellae on the drum surface can be spaced axially and / or radially away from the lamellae on the lateral lye container wall.

According to the invention, the protruding structures, in particular lamellae, can differ from each other in their number, arrangement, shape and / or size. These are chosen as a function of the desired influence on the flow suitable.

It is generally considered that the protruding structures on the surface enhance radial air flow. Preferably, the protruding structures are therefore chosen such that a radial flow around the drum is at least partially converted into an axial air flow directed towards the rear tub wall.

This can be achieved, for example, by attaching outwardly projecting structures on the lateral tub wall. A rotating air mass is then at least partially reshaped by the lamellae located on the inside of the tub, in particular the lateral tub wall, into an axial flow.

In this case, molding of the lamellae during the production of the lye container is preferred.

In a very particularly preferred embodiment of the invention, the protruding structures, in particular lamellae, on the drum surface and on the side tub wall wall in terms of number, arrangement, shape and / or size during the rotation of the drum in their influence on the air flow complement each other such that greater axial flow towards the rear tub wall results. Preferably, for this purpose as much as possible of a radial flow around the drum is converted into a flow directed towards the rear tub wall.

When protruding structures, particularly lamellae, are used on the drum surface and side tub wall, their arrangement, size and number are generally similar. However, the direction of inclination of the structures on the drum surface is usually opposite to that on the side tub wall. When using slats is then spoken of counter blades.

Through the use of lamellae on the drum and counter-lamellae in the tub, these having a radial distance from each other, can be implemented by the interaction of a substantial part of the rotating flow around the drum in an axial flow. As a result, in particular the formation of a rotating water ring is counteracted.

It is also advantageous to provide a number of rings with protruding structures on the drum and side tub wall, e.g. Lamella and counter blades with a radial overlap. These would mesh with each other during operation of the drum. Such an arrangement has a high efficiency in terms of generating an axial compensation flow and reducing the rotating flow rate.

In a further embodiment of the invention beads are arranged on the drum surface as outwardly projecting structures. Thus, externally embossed helical beads can be incorporated into the drum. These can affect the flow on the drum surface according to the invention, in particular also contribute to a compensation of the opposing axial flows.

In a preferred embodiment of the invention, drainage holes are arranged on the drum surface with arranged obliquely to the axis of rotation of the drum tulips as protruding structures. The drainage holes can be suitably shaped for this purpose, eg elliptical. In this case, "tulips" are understood in particular to be outwardly directed collars, eg funnel-shaped collars. These can be shaped such that preferably tulips arranged helically on the drum surface be present and achieve a desired effect according to the invention in this way.

Moreover, these tulips can advantageously lie in the direction of lamellae also used on the drum surface.

The tulips are preferably used as a supporting measure, e.g. together with lamellae on a side lye container wall.

In the production, for example, starting from a sheet metal part, punched sheet metal parts can remain on one side of the drainage holes and be used as outwardly projecting structures in the context of the invention.

Moreover, a seam closing the drum can be designed as a spot weld with bent sheet metal ends as structures projecting outwards. Usually, a drum is made by bending a sheet and welding the sheet ends together. Such a seam can be provided obliquely in the blank of the sheet, so that it runs in the finished drum helically on the drum surface. When forming the seam as a spot weld with bent sheet metal ends then results in a helical, protruding structure in the context of the invention. Such seams can also be incorporated several times, preferably three times, in the drum shell. In addition, additional protruding structures can be incorporated as a correspondingly shaped blind seam. These would be, for example, in the drum shell inflected ribs.

In the present invention, it is particularly advantageous that the protruding structures on the drum surface and / or the side tub wall have a pitch, relative to the axis of rotation of the drum, which increases from the back tub wall towards the door of the washing machine.

In a further preferred embodiment of a washing machine according to the invention, the suds container wall, in particular the lateral suds container wall, can be suitably structured in order to facilitate an outflow of the water located on it and / or to reduce the velocity of an air flow on its surface. in the In general, the structuring of the tub interior side can be achieved by various protuberances or recesses or by the arrangement of at least one component on the tub wall. For example, grooves or beads would be conceivable as depressions.

Preferably, in a front area of the drum facing the door and / or in a region of the drum facing the rear tub wall, less drainage holes may be provided than in the middle, since in these areas the holes are highly permeable to air in all probability the middle of the drum when hurling the Wäschering the local drainage holes covered. Thus, the air circulation should be reduced overall.

Advantageously, in addition, the drum gap can be narrowed, for example, by a suitable construction of the sleeve, wherein the drum gap is narrowed, in particular in the areas of the presumed Rückbefeuchtungs inflow.

The invention also relates to a method for operating a washing machine for the treatment of laundry with a program control, a water supply system, a drum rotatably mounted in a tub and a drive motor for the drum, wherein on a drum surface and / or a side tub wall in a space between the drum and the tub outwardly projecting structures are arranged which generate upon rotation of the drum about a substantially horizontal axis of rotation directed towards a rear tub wall axial air flow, wherein in the method, the drum is rotated at such a rotational speed and thereby such air flow around the drum, the protruding structures reduce a velocity of axial air flow relative to a washing machine without these structures.

In a preferred embodiment of this method, the drum is operated in the last spin step with a compensation speed at which substantially no axial and / or radial air flow in the intermediate space takes place.

In an alternative embodiment of the method according to the invention, the drum is operated in the last spin step at a speed above a compensation speed at which substantially no axial and / or radial air flow takes place in the intermediate space. That in particular, that the rotational speed is so high that an axial air flow is present in the direction of a rear tub wall. This can be reduced, for example, a reinforced rewetting during the reduction of the rotational speed of the drum during Abtouren, since the air flow takes a long time axially towards a rear tub wall.

Inventive washing machine and method according to the invention have numerous advantages. The washing machine according to the invention has the advantage that the axial flow of the air, which is usually directed forward in the direction of the door of the washing machine, can be reduced or even compensated. This makes it possible to return water to laundry in the drum, i. a rewetting, reduces and thus improves the residual moisture. In this way, the drying process of the laundry following the washing can be considerably shortened without the need for prolonging the spinning step. This is very advantageous for reasons of economy and environmental protection. As part of the air flow is eliminated, a saving of energy, a longer life of the engine and other machine components can be achieved. In addition, the operation of the washing machine with a lower required drive power, larger accelerations, especially in the higher speed range, and in embodiments also a reduction of flow noise is possible.

In embodiments of the invention, moreover, the radial flow can be significantly reduced, so that the formation of a continuously moving in a circle water ring can be counteracted to the tub wall. As a result, the water produced during the spin phase can be better dissipated. Overall, a spin phase can be shortened in time. As a result, the components of the washing machine (in particular drive motor and bearings) are spared and it is consumed less energy.

• Fig. 1 ein Schnitt durch eine erste Ausführungsform einer Waschmaschine, der Schnitt geführt in Richtung der Drehachse der Trommel,
• Fig. 2 eine schematische Darstellung der vorliegend relevanten Teile einer zweiten Ausführungsform einer Waschmaschine, und
• Fig. 3 ein Schnitt durch eine dritte Ausführungsform einer Waschmaschine, der Schnitt ebenfalls geführt in Richtung der Drehachse der Trommel.

Preferred embodiments of the invention are illustrated in the figures of the attached drawing and will be explained in more detail below with reference to these figures. There are:

• Fig. 1 a section through a first embodiment of a washing machine, the cut out in the direction of the axis of rotation of the drum,
• Fig. 2 a schematic representation of the presently relevant parts of a second embodiment of a washing machine, and
• Fig. 3 a section through a third embodiment of a washing machine, the cut also guided in the direction of the axis of rotation of the drum.

Fig. 1 is a section through a first embodiment of a washing machine in the direction of the axis of rotation 3 of the drum 2 and thus shows a section through a side view. The tub 1 can be opened at the front by a door 19 with a bull's eye glass, which is sealed by a collar 20.

At the in Fig. 1 shown first embodiment are on the drum surface 28 axially spaced from each other front slats 16 and rear slats 22 as protruding structures according to the invention arranged. In addition, also axially spaced from each other on the side tub wall 27 front lamellae 17 (counter blades with compared to the situation on the drum surface reversed slope) and rear slats 23 are arranged. The rear fins 22 and 23 are arranged on the side of the tub side wall 27 and the drum surface 28 that they can mesh with each other during a rotation of the drum 2. However, the combing effect is greater if - not shown here - the rear slats protrude more strongly into the intermediate space 26 between the tub 1 and drum 2 and there is a radial overlap between them. The front fins 16 and 17 on the side tub wall 27 and the drum surface 28, however, are opposed to each other.

Fig. 1 shows the situation when spinning, whereby by the rotation of the drum 2 about the axis of rotation 3, the laundry 7 as a laundry ring substantially the drum inside is applied. By the rotational movement of the drum 2, a complex air flow is generated with a radial and an axial component, of which only the axial flow in the intermediate space 26 is shown here with arrows, which in the present case by a generated axial counterflow in the direction of the rear tub wall 24 at least reduced and is preferably compensated. This air flow circulates through the drainage holes 18 of the drum 2 according to the pressure equalization and passes through the drum gap 21 back into the interior of the drum 2, where entrained water droplets can hit the laundry and so contribute to the rewetting, if this flow is not counteracted according to the invention.

At the in Fig. 1 shown first slats 16 are arranged in a front half 29 of the drum surface 28 and fins 17 and 23 in a front half of the side tub wall 27.

Fig. 2 is a schematic representation of the presently relevant parts of a second embodiment of a washing machine. The washing machine has a tub 1, in which a drum 2 is rotatably mounted about a substantially horizontal axis of rotation 3 and can be operated by a drive motor 14. Wäschemitnehmer 4 and scooping devices 5 on the inner surface of the drum shell for example, a wash liquor 6 allow intensive washing of the laundry 7 with 6 or water wash.

The washing machine also has a liquor inlet system, which includes a water connection fitting for the domestic water network 8, an electrically controllable valve 9 and a supply line 10 to the tub 1, which is guided via a dispenser 11, from the incoming water detergent can carry into the tub 1.

Also located in the tub 2 is a heater 13. 15 means a pump for the liquid contained in the tub 1 and the drum 2. Valve 9, heater 13 and drive motor 14 may be controlled by a program controller 12 in response to a program schedule.

At the in Fig. 2 shown second embodiment of a washing machine are in the space 31 between the drum 2 and tub 1 on the drum surface 28 a total of four arranged as a helical in a ring slats 17 as protruding structures available. During a rotation of the drum, these generate an axial air flow in the direction of a rear suds container wall (not shown here in detail).

The arrow indicates the direction of rotation of the drum 1 and thus the flow direction of the air. 25 means a radiator pocket in which centrifuged water is collected for pumping.

In Fig. 3 is a side view of a third embodiment of a washing machine shown. In this embodiment, fins 16 are arranged in a front half 29 of the drum surface 28 and a front half 30 of the side tub wall 27. 19 means a door, 21 the drum gap and 24 the rear tub wall.

LIST OF REFERENCE NUMBERS

1

tub

2

Drum, laundry drum

3

Rotary axis of the drum

4

laundry agitator

5

scooping devices

6

suds

7

Laundry

8th

Domestic water supply

9

Valve

10

supply

11

dispenser tray

12

program control

13

heater

14

drive motor

15

pump

16

front slats on laundry drum

17

front lamellae on lateral tub wall

18

Drain hole in the drum

19

Door, with bullseye glass

20

cuff

21

drum gap

22

rear slats on laundry drum

23

Rear slats on the side of the suds tank wall

24

rear tub wall

25

radiators pocket

26

Space between tub and laundry drum

27

lateral suds tank wall

28

drum surface

Claims (15)

Washing machine for treating laundry with a program control (12), a water supply system (8, 9, 10, 11), a drum (2) rotatably mounted in a tub (1) and a drive motor (14) for the drum (2), characterized in that arranged on a drum surface (28) and / or a side tub wall (27) in an intermediate space (26) between the drum (2) and the tub (1) protruding structures (16,17,22,23) are, which generate upon rotation of the drum (2) about a substantially horizontal axis of rotation (3) directed towards a rear tub wall (24) axial air flow. Washing machine according to claim 1, characterized in that the protruding structures (16,17,22,23) form a helical structure. Washing machine according to claim 2, characterized in that the projecting structures (16, 17, 22, 23) are helically arranged lamellae. Washing machine according to one of the preceding claims, characterized in that the protruding structures (16,17,22,23) are arranged regularly in a ring around the drum surface (28). Washing machine according to one of the preceding claims, characterized in that the protruding structures (16,17,22,23) in a front half (29) of the drum surface (28) and / or a front half (30) of the lateral tub wall (27 ) are arranged. Washing machine according to one of the preceding claims, characterized in that on the drum surface (28) and on the side lye container wall (27) fins are arranged as outwardly projecting structures (16,17,22,23). Washing machine according to claim 6, characterized in that the lamellae (16, 17, 22, 23) on the drum surface (28) are axially and / or radially spaced from the lamellae on the lateral tub wall (27). Washing machine according to one of claims 6 and 7, characterized in that the lamellae on the drum surface (28) and on the side tub wall (27) in number, arrangement, shape and / or size during rotation of the drum (2) in their Supplementing influence of the air flow in such a way that a larger axial flow in the direction of the rear tub wall (24) results. Washing machine according to one of the preceding claims, characterized in that beads are arranged on the drum surface (28) as outwardly projecting structures (16, 22). Washing machine according to one of the preceding claims, characterized in that arranged on the drum surface (28) drainage holes (18) with obliquely to the rotation axis (3) of the drum (2) arranged tulips as outwardly projecting structures (16,22). Washing machine according to one of the preceding claims, characterized in that at least one of the drum (2) closing seam is formed as a spot weld with bent sheet metal ends as protruding structures (16,22). Washing machine according to one of the preceding claims, characterized in that the protruding structures (16,17,22,23) on the drum surface (28) and / or the side tub wall (27) has a pitch, with respect to the axis of rotation (3) Drum (2), which increases from the rear tub wall (27) towards the door (19) of the washing machine. Method for operating a washing machine for treating laundry with a program control (12), a water supply system (8, 9, 10, 11), a drum (2) rotatably mounted in a tub (1) and a drive motor (14) for the drum (2), wherein on a drum surface (28) and / or a side tub wall (27) in a space (26) between the drum (2) and the tub (1) protruding out structures (16,17,22,23) are arranged, which generate upon rotation of the drum (2) about a substantially horizontal axis of rotation (3) in the direction of a rear tub wall (24) directed axial air flow,
characterized in that the drum (2) is rotated at such a rotational speed and thereby generates such air flow around the drum (2) that the protruding structures (16, 17, 22, 23) relate a speed of axial air flow to a washing machine without these structures (16,17,22,23), reduce. A method according to claim 13, characterized in that the drum (2) is operated in the last spin step with a compensation speed at which substantially no axial and / or radial air flow in the intermediate space (26) takes place more. A method according to claim 13, characterized in that the drum (2) is operated in the last spin step at a speed above a compensation speed at which substantially no axial and / or radial air flow in the space (26) takes place more.

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