Laundry treatment device with steaming function and method for steaming laundry

Abstract

A laundry treatment device (1) with a steaming function is provided. The laundry treatment device (1) comprises a tub (2) which includes a heating element pocket (3) with a heating element (4) contained therein, a drum (5) which is rotatably arranged in the tub (2), a door (6) for closing an opening of the tub (2) through which the drum (5) is accessible, wherein the door (6) has a sight glass (7) projecting towards the drum (5) and wherein the heating element pocket (3) is arranged lower than the door (6) in an operating position of the laundry treatment device (1), a water supply line (8) which is configured to supply water to the heating element pocket (3), wherein the water supply line (8) is positioned in the tub (2) such that the water to be supplied to the heating element pocket (3) can flow over the projecting sight glass (7), and a control unit (9) which is configured toto control the flow rate of the water to be supplied through the water supply line (8) to the radiator pocket (3) in such a way that the water bypasses the drum (5) along the protruding sight glass (7) and can be directed into the radiator pocket (3).

Description

[0001] The present invention relates to a laundry treatment appliance with a steaming function and a method for steaming laundry in a laundry treatment appliance.

[0002] Some laundry treatment appliances, particularly washing machines, already have a steaming function in the state of the art. This usually involves converting water in a tub into hot steam using a heating element and then directing this steam into a drum containing the laundry. A steaming function can be used either in combination with a wash program or separately. The steaming function can minimize wrinkles in the laundry, remove odors and / or allergens, and / or replace additional treatment agents such as fabric softener or other chemical cleaning agents. Using the steaming function alone can also be used to freshen up laundry, e.g., remove wrinkles and odors from clothes that have been worn once.

[0003] In the current state of the art, the steaming function is primarily used in combination with a regular wash program, meaning that the laundry getting wet when adding water intended for the steaming function is of little importance, as the laundry is already thoroughly moistened as part of the wash program. An existing water inlet can also be used, designed to moisten laundry in the drum as quickly and thoroughly as possible. However, if steaming is to be performed without the laundry becoming soaked or developing water spots, the existing water supply system of a laundry treatment appliance is unsuitable.

[0004] Furthermore, it is desirable to implement steaming in existing laundry treatment appliances with as little adaptation as possible, so that the laundry does not become soaked.

[0005] EP 2 733 250 A1 proposes a valve for controlling a water supply with timed openings. The valve should have opening intervals of less than 0.5 seconds. This is intended to limit the water flow so that the laundry is prevented from being moistened by the incoming water, while still ensuring that sufficient water is supplied to the steaming system. In practice, however, it is very difficult to implement such a rapidly timed valve with the electronics present in the laundry treatment appliance, which is why its use is not possible without major modifications to the laundry treatment appliance. If the valve is timed at longer intervals, the water flow cannot be controlled less precisely, which can lead to undesirable moistening of the laundry (e.g., water stains on the laundry).

[0006] US 2014 / 0299164 A1 shows a washing machine with a water supply into the drum, which is designed to clean a window and the window seal through the water supply.

[0007] US 2009 / 0272155 A1 shows a washing machine with a steaming function. A heater is supplied with water through a specially designed supply line.

[0008] WO 2016 / 062349 A1 discloses a washing device for refreshing laundry. The washing device has a liquid reservoir in which a heating device is arranged, which is designed to heat the liquid in the liquid reservoir. A water supply device is provided for supplying water to the liquid reservoir.

[0009] EP 2 636 784 A1 discloses a washing machine that can perform a washing operation using bubbles. For this purpose, the washing machine has a fluid supply into a space between a washing drum and the inner wall of a tub. From there, the fluid flows to a porous element at which an air supply line also ends, allowing bubbles to be generated.

[0010] US 2019 / 0323161 A1 shows a method for controlling a washing machine, in which the amount of laundry in the washing machine is determined and, based on this, an amount of water is supplied for washing the laundry.

[0011] KR 100605732 B1 shows a drain hose for a washing machine that is located in a door seal. The drain hose is designed so that any remaining water can be drained away immediately after the end of a wash cycle.

[0012] KR 100651979 B1 shows a drum washing machine capable of dry cleaning. For this purpose, the washing machine has a heating device to which water can be supplied via a water inlet.

[0013] The present invention is therefore based on the object of providing a laundry treatment appliance with a steaming function and a method for steaming, in which the laundry is effectively prevented from becoming wet when the water for the steaming function is added. At the same time, the redesign effort required to implement the steaming function in an existing laundry treatment appliance should be as minimal as possible.

[0014] This object is achieved by a laundry treatment appliance according to claim 1 and a method according to claim 9. Further advantages and features emerge from the dependent claims as well as the following description and the figures.

[0015] According to a first aspect of the present invention, a laundry treatment appliance with a steaming function is provided, wherein the laundry treatment appliance comprises: a tub comprising a heating element pocket with a heating element accommodated therein, a drum rotatably arranged in the tub, a door for closing an opening of the tub through which the drum is accessible, wherein the door has a viewing window projecting towards the drum and wherein the heating element pocket is arranged lower than the door in an operating position of the laundry treatment appliance, a water supply line configured to supply water to the heating element pocket, wherein the water supply line is positioned in the tub such that the water to be supplied to the heating element pocket can flow over the projecting viewing window, and a control unit configured toto control the volume flow of water supplied through the water supply line to the radiator pocket in such a way that the water bypasses the drum along the protruding sight glass and can be directed into the radiator pocket.

[0016] The laundry treatment appliance can be, for example, a washing machine or a washer-dryer. The laundry treatment appliance is provided with a steaming function. While the steaming function is running, water in and / or near the heating element pocket can be heated by the heating element and subsequently evaporated. The steam thus generated can be fed into the drum and come into contact with laundry stored in the drum. The steaming function can be part of a laundry treatment program or can be performed separately.

[0017] The suds container can be suspended in a vibration-damped manner in a housing of the laundry treatment appliance. Furthermore, the suds container can be designed to be watertight with the exception of at least one water supply (e.g. the water inlet) and one water outlet. In particular, the suds container can have the water inlet, which is provided in the region of the opening, and a main water inlet, which is arranged such that it can direct water directly onto the drum. The suds container can be cylindrical and have an opening at one axial end thereof, which opening can be closed with the door. The suds container can accommodate the drum inside it. An intermediate space can be formed between the suds container and the drum, the size of which can be selected such that an imbalance in the drum during operation of the laundry treatment appliance does not lead to contact between the drum and the suds container.In other words, when there is water in the tub, the drum can be above the water level so that no water enters the drum.

[0018] The radiator pocket can be a component suitable for receiving and collecting water. The radiator pocket can be a depression or protrusion of the tub. The radiator pocket can be arranged at the lowest point of the tub with respect to the direction of gravity when the laundry treatment appliance is in operation. This ensures that as soon as water is supplied to the tub, it reaches the radiator pocket. Advantageously, the radiator pocket can have one or more openings that enable an exchange of water and / or water vapor between the radiator pocket and the tub. Furthermore, the radiator pocket can be arranged at a lower position than the drum, ensuring that the steam generated by the radiator pocket can easily reach and into the drum.In addition, the radiator pocket can be arranged in the suds container in such a way that the water can flow directly from the sight glass into the radiator pocket. Alternatively, the radiator pocket can be arranged in such a way that the water from the sight glass first flows onto an inner surface of the suds container and from there to the radiator pocket (i.e. is fed indirectly to the radiator pocket). Preferably, the radiator can be arranged in the radiator pocket in such a way that it has good thermal contact with the water in the radiator pocket. For this purpose, the radiator can be provided, for example, as a spiral in the radiator pocket. Advantageously, the radiator can be arranged in the radiator pocket in such a way that it is completely covered with water when the radiator pocket is filled with water. The radiator can, for example, be a heating rod, a tubular heating element and / or a heating coil.Furthermore, the radiator pocket can be equipped with a sensor that can determine whether the radiator pocket is filled with enough water to cover the radiator. This can prevent the radiator from overheating if there is too little water in the radiator pocket.

[0019] In an operating position, lowered with regard to the radiator pocket can mean that the radiator pocket is arranged at a lower height than the door in a spatial arrangement and orientation of the laundry treatment appliance intended for operation. In other words, the water supply line, the sight glass and the radiator pocket can be arranged in such a way that in an operating position, water is driven by the force of gravity, reaches the sight glass from the water supply line and runs down the sight glass, with the water subsequently reaching the radiator pocket directly or indirectly. Consequently, water can be supplied to the radiator pocket without the water entering the drum or passing through it beforehand. Furthermore, water can be supplied to the radiator pocket solely by means of gravity, without pumping or similar being necessary.

[0020] The drum is preferably designed to accommodate laundry therein. Furthermore, the drum can have a cylindrical shape that can be open at one axial end thereof. In order to be able to guide the steam smoothly into the drum, the drum can have a plurality of through-holes in its peripheral surface or shell surface. The drum can be rotatably held in the tub. Advantageously, the drum is designed so that, when the door is open, laundry can be placed into the drum through the opening of the tub. In particular, the opening of the drum can substantially correspond to the opening of the tub and face towards it. Water can be supplied to the drum by directing the water directly through the main water inlet around the circumference of the drum and entering the drum through the through-holes.Water can also be added to the drum by letting water into the tub until the drum is submerged in water to a certain extent. Depending on the wash cycle being performed, the recommended water supply methods can also be combined.

[0021] The door can be moved from a first position, in which the door is closed, to a second position, in which the door is open such that the drum is accessible from the outside. The door can in particular be designed such that it enables a fluid-tight and / or watertight closure of the tub from the environment (i.e. when the door is in the first position). For this purpose, the laundry treatment appliance can, for example, have a sealing sleeve with which the door interacts (details follow below). The door has a sight glass that protrudes towards the drum. Furthermore, the sight glass can protrude at least partially into the drum. The sight glass can protrude towards the drum when the door is in the first position. The sight glass can be transparent so that a user can see into the interior of the drum when the door is closed. In particular, the sight glass can protrude into the drum.The sight glass can extend over at least 60% of the door surface, preferably over at least 80% of the door surface. This ensures that a user has a good view into the drum. The door can have a frame surrounding the sight glass. Preferably, a central sight glass region of the door, when the door is in the first position, can protrude further into the interior of the tub than an outer region of the door, in particular an outer region of the door that does not have a sight glass. In other words, the protruding sight glass can have a tapered shape. This can ensure that the water fed to the protruding sight glass can be reliably drained along the sight glass. In particular, this can ensure that the adhesion forces that hold the water to the sight glass are greater than the kinetic forces of the water.This ensures that the laundry in the drum does not get wet due to the water being fed into the radiator pocket.

[0022] A water impact point can be formed on the sight glass, onto which the water flowing from the water supply line impacts the sight glass. The water impact point can be formed next to a vertex of the protruding sight glass. This ensures that the water does not splash away from the water impact point, but runs along the sight glass. The protruding sight glass can have an inclined sight glass geometry. The inclined sight glass geometry can be a region of the sight glass that is flat and inclined with respect to the horizontal. The water impact point can be located in the inclined sight glass geometry. This can even more reliably prevent water from splashing away from the inclined sight glass geometry. From the water impact point, the water can then be drained along the sight glass thanks to the water's adhesion to the sight glass.In other words, the water can be guided from the point of impact along the sight glass to the lowest point of the sight glass (e.g., to a point opposite the apex of the sight glass) and from there drip or flow off. While the water flows along the sight glass, the water can always be in contact with the sight glass. This reliably ensures that no water enters the drum. In other words, the water can be drained along the sight glass, bypassing the drum.

[0023] The control unit can be a computer-like circuit that can receive, process, and output signals. For this purpose, the control unit can have a CPU and a memory. The control unit can control, in particular limit, the volume flow of water to be supplied to the water supply line by means of an actuator (e.g. a valve). In particular, the control unit can be designed to keep the volume flow so low that the water reliably runs along the sight glass and does not enter the drum. Thus, in addition to the design of the sight glass and the arrangement of the water supply line, the control unit can ensure that the water supplied to the radiator pocket bypasses the drum and does not moisten the laundry inside. By controlling the volume flow, it can be ensured that the water directed from the water supply line onto the sight glass does not splash towards the drum.Such splashing can occur if the volume flow of water exiting the water supply line is too high. Advantageously, the control unit can be designed such that it can control a volume flow through the water supply line by closing and opening the water supply line. For example, it can be designed to adjust a flow cross-section of the water supply line at a control point. In particular, the control unit can be designed to control the volume flow flowing through the water line by means of a closing mechanism. The closing mechanism can be, for example, a valve, a butterfly valve, a gate valve, or a ball valve.

[0024] A water inlet that can be used to direct water onto a sight glass is known from the prior art. In many cases, a portion of the water supplied to the tub during a wash cycle is directed onto the sight glass so that it flows directly into the drum to ensure that the laundry in the drum is quickly wetted. Such an arrangement has the advantage that a user can see how the water is being supplied to the drum immediately after a wash program has started. This serves as feedback to the user that the laundry treatment appliance has started working. Furthermore, moistening the sight glass has the advantage of reducing the friction between the sight glass and the laundry in the drum during operation of a laundry treatment appliance.

[0025] According to the invention, this existing water inlet is used as a water supply line to supply water to the radiator pocket, bypassing the drum. However, this requires regulating the volume flow of the water directed to the sight glass so that the water does not enter the drum but is instead diverted through the sight glass. Furthermore, the water supply line can be arranged to ensure reliable drainage of the water along the sight glass. Furthermore, the sight glass can be designed so that the water can be diverted along the sight glass without entering the drum. The water diverted along the sight glass can then be fed directly or indirectly to the radiator pocket.

[0026] The water supply line can be a pipe that communicates with a general water supply line to the laundry treatment appliance. In addition, the water supply line can communicate with the outlet of a pre-wash chamber. Furthermore, the water supply line can have an opening above the door (with respect to the direction of gravity in an operating position of the laundry treatment appliance) from which water can be discharged. Furthermore, the opening of the water supply line can have a nozzle that can be designed to direct the water supplied to the heating element pocket onto the projection of the sight glass in a defined manner. Defined can mean that the nozzle can discharge the escaping water in a specific direction and / or at a specific flow rate. This can reliably prevent water from the sight glass from entering the drum.In particular, the nozzle can be designed to reduce the flow velocity of the water exiting the water supply line. This can reliably prevent water from splashing into the drum.

[0027] According to the invention, a steaming function can be implemented in a laundry treatment appliance using existing components. For example, an existing water line can be used to supply water to the sight glass in a defined manner. From there, the water can be supplied to the heating element pocket, bypassing the drum, thus reliably preventing the laundry in the drum from becoming damp. Furthermore, a control unit is provided that can control the volume flow of the water supplied to the heating element pocket.

[0028] In contrast, the laundry treatment appliances known in the prior art are not designed to adjust a flow rate in such a way that reliably prevents the laundry in the drum from becoming wet. More specifically, the laundry treatment appliances known in the prior art are designed to supply a defined amount of water to the tub, which is required, for example, during a main wash cycle and / or pre-wash cycle. The water flow rate is not relevant, but only the total amount of water supplied to the tub. Furthermore, the control tolerances are relatively large, so the flow rate of the supplied water can fluctuate considerably from wash cycle to wash cycle.

[0029] According to an advantageous embodiment, the projecting sight glass of the door can be designed as a conical projection in the direction of the drum, wherein the water supply line can be arranged such that the water can be directed onto the jacket region of the projection, in particular onto a region which is closer to the origin of the projection than to its end projecting towards the drum.

[0030] In particular, the position and angle of an opening in the water supply line can be designed such that the water can be directed onto the casing region of the projection. The conical projection can extend partially into the drum. However, it can also be arranged completely outside the drum (i.e. only in the area of the door and the tub). Advantageously, the water supply line can be arranged such that it directs the water onto an upper region of the casing region when the laundry treatment appliance is in the operating position, in particular onto a region of the casing that is closest to the water supply line. The sight glass can preferably be truncated cone-shaped. It has been found that a conical shape of the sight glass is well suited to controlled drainage of water. In particular, a suitable arrangement of the water supply line can ensure that the water runs down the casing surface.Advantageously, the sight glass can be designed such that a trickle forms on the outer surface of the cone when water from the water supply line is directed onto the outer surface. In other words, the water can be drained along a circumferential direction of the conical projection on the sight glass. In particular, the conical projection can be designed such that the water can be drained downwards from the lowest point of the conical projection.

[0031] According to one embodiment, the projection may have a contour which is designed to divert the water to be supplied to the radiator pocket in a defined manner via the projection, bypassing the drum.

[0032] In this context, defined drainage can mean that the water is guided in a targeted manner. In other words, the water can be drained along a predetermined path along the projection without the water entering the drum. The contour can, for example, be in the form of a groove or depression. Preferably, the contour can run in an annular or partially annular manner on the jacket region of the conical projection. The contour can run from the point of impact of the water to the lower region of the protruding sight glass. The annular contour can enclose a surface that is essentially parallel to the cross-sectional area of the opening. It is also conceivable for the contour to define a surface region on the projection that has different surface properties than the other surface properties of the projection, for example a different roughness and / or a different adhesion force to water.This allows surface friction to be lower in the area of the contour than at the rest of the projection. This makes it easier for water to flow along the contour. Consequently, water from the projection can be reliably prevented from entering the drum.

[0033] The control unit is designed to control the volume flow to a value in the range of 0.1 I / min to 2.0 I / min, preferably 0.2 I / min to 1.0 I / min and particularly preferably 0.3 I / min to 0.7 I / min.

[0034] As described above, the control unit can actuate a control element to set a specific volume flow. For example, the control unit can control a valve such that the defined volume flow is achieved. The valve can be designed to have a maximum volume flow that lies at the upper limit of the range defined above. Alternatively, the control unit can be designed to cycle a valve with a larger maximum volume flow so that a volume flow within the range defined above is achieved. A volume flow within the range defined above can ensure that the water is reliably drained away at the projection without water entering the drum. Furthermore, the amount of water required for the steaming function can be quickly supplied to the radiator pocket to ensure a time-saving steaming function.

[0035] Preferably, the suds container can have a sealing sleeve which, when the door is closed, seals the opening of the suds container together with the door, and wherein openings are arranged on or near the sealing sleeve through which water diverted at the projection can be fed directly to the radiator pocket.

[0036] In the present embodiment, the water supply line can be a sleeve flush. In particular, the openings can preferably be arranged below the protruding sight glass, so that water drained from the sight glass can be directed directly to the area of the sealing sleeve where the openings are provided. The water can then flow through the openings into the tub beneath the drum and from there to the radiator pocket. Alternatively, the radiator pocket can also be arranged directly below the openings, so that the water can be supplied directly from the openings in the radiator pocket. For example, the openings can be holes, in particular circular, oval, or square holes. The presence of several openings can ensure even distribution of the drained water.The sealing sleeve is preferably arranged concentrically to the sight glass, whereby it can sag downwards when the tub is full, in particular when filled with water, without negatively affecting the sealing effect. For example, the sealing sleeve can be a bellows, in particular a rubber bellows. The sealing sleeve can serve as a sealing connection between an oscillating region (tub and drum) and a housing and door of the laundry treatment appliance that are stationary relative thereto. In particular, the sealing sleeve can serve as a sealing lip to seal the opening with the door and / or the sight glass. The sealing sleeve can preferably have folds. The openings or at least a gap can be provided between the folds to drain the water.

[0037] Preferably, the control unit can be designed to open and close a first valve arranged upstream of the water supply line in order to control the volume flow of the water to be supplied to the radiator pocket for the steaming function.

[0038] The volume flow can also be referred to as flow rate or flow. The valve can be a solenoid valve and / or a diaphragm valve, for example. The valve can be clocked, in particular designed to open and close at a predetermined frequency under the control of the control unit. The clocking can reduce the amount of water that passes through the valve per unit of time (i.e. the volume flow). In particular, the valve can be designed such that it can reduce its maximum volume flow, which is determined in particular by the flow cross-section of the valve, at a specific clocking. The valve can be a pre-wash valve, via which the water for a pre-wash program is also directed and controlled. This can be achieved in particular if the volume flow through the pre-wash valve can be set to be sufficiently low.It can preferably be provided that the water fed through the pre-wash valve does not run through the main water supply, which directs the water directly onto the drum. This would result in moistening of the laundry. In contrast, the water supply controlled by the pre-wash valve can be via the water supply line, so that the water from the pre-wash valve is fed to the sight glass. However, it is also conceivable for the valve to be an additional valve used exclusively for the steaming function. The valve can be specially designed for low volume flows. In other words, the valve can have such a small flow cross-section that the volume flow can be adjusted according to the definitions above. This can be necessary or useful in particular if, for example, a pre-wash valve cannot provide a sufficiently low volume flow.In known laundry treatment appliances, pre-wash valves are designed to achieve a flow rate in the range of 2 l / min to 10 l / min. This can be disadvantageous for the steaming functions according to the invention, as it cannot ensure that the water can be fed directly to the heating element pocket, bypassing the drum.

[0039] According to one embodiment, the laundry treatment appliance may further comprise a second valve and a third valve, wherein the second valve may be configured to supply water for a main wash cycle to the tub, wherein the third valve may be configured to supply water for a pre-wash cycle to the tub via the water supply line.

[0040] In particular, the first valve can be designed to allow a lower volume flow than the second valve and / or the third valve. Preferably, the three valves can be arranged in parallel. A parallel arrangement can mean, in particular, that the valves are not arranged one behind the other. In other words, a parallel arrangement can mean that a water flow only flows through one of the first and second valves, although it is not necessarily impossible for different water flows to be passed through two or three valves at the same time. Preferably, the first valve can be designed to supply water to the same water path as the third valve (i.e., the water supply line).In particular, a water converger, for example a Y-piece, can be arranged downstream of the first valve and the third valve, which is designed to combine water from the first valve and water from the third valve in a common line. The second valve can be designed to supply water to the main water inlet. The three valves can be part of a valve arrangement that can be controlled by the control unit. The valve arrangement can comprise a Y-piece, which can be arranged downstream of the first and third valves and which can be designed to combine water coming from the first valve and water coming from the third valve into a common line. The Y-piece can be an integral part of the valve arrangement or the Y-piece can be attached to the valve arrangement.Alternatively, it is also conceivable that a hose can be connected to the valve arrangement, which comprises a Y-piece with three ends, wherein the first and the second end are connected to outlets of the first and the third valve and wherein the third end can direct the water towards the water supply line.

[0041] The control unit can preferably be configured to supply 0.5 l to 5 l, preferably 1 l to 2 l, and particularly preferably 1.3 l to 1.7 l, of water to the heater pocket for the steaming function. A suitable total water supply can ensure, on the one hand, that the water level in the layer container is not too high, i.e., that the water does not reach the drum and the laundry contained therein, and, on the other hand, ensures that the heater is immersed in the water to ensure evaporation of the water without the heater overheating.

[0042] Advantageously, the laundry treatment appliance can comprise a treatment agent container arranged upstream of the water supply line, wherein the treatment agent container can have a main wash chamber for a treatment agent for use during a main wash cycle and a pre-wash chamber for a treatment agent for use during a pre-wash cycle. The treatment agent container can be designed such that the water to be supplied directly to the heating element pocket for the steaming function can be passed through the pre-wash chamber. In other words, the water supply line used for the steaming function can lead through the pre-wash chamber of the treatment agent container. Thus, a water supply line already available in the prior art can advantageously be used for the steaming program of the laundry treatment appliance according to the invention.

[0043] For example, the treatment agent container may have a first water outlet and a second water outlet, wherein the first water outlet may be configured to supply the water to the drum, and wherein the second water outlet may be configured to supply water to the water supply line.

[0044] In particular, the control unit can be configured such that, for the steaming program, it only supplies water to the second water outlet. Preferably, during the steaming program, water enters the tub exclusively via the second water outlet and the water supply line. The first water outlet can be connected to the main water inlet. Accordingly, water can be supplied from the second valve via the main wash chamber to the main water inlet. Furthermore, water can be supplied from the first valve and / or the second valve to the water supply line and thus to the sight glass.

[0045] A further aspect of the invention is a method for steaming laundry in a laundry treatment appliance, the method comprising: Providing a laundry treatment appliance according to one of the previously described embodiments, controlling a volume flow of water supplied from the water supply line so that the water is supplied to the heating element pocket bypassing the drum, wherein the water is passed through the water supply line via the sight glass, and heating the water in the tub by the heating element accommodated in the heating element pocket so that the generated steam flows into the drum.

[0046] The generated steam can, for example, be directed into the drum through holes formed in the drum. During a steaming process, the drum can rotate to ensure even contact of the laundry inside the drum with the steam. All of the described advantages and features of the laundry treatment appliance can be applied analogously to the process, and vice versa.

[0047] According to a further aspect of the present invention, the use of a laundry treatment appliance is advantageous in which a water supply line used for cuff rinsing is supplied with water at a low volume flow in order to supply water to the heating element pocket while bypassing the drum. According to the invention, the low volume flow is in the range of 0.1 l / min to 2.0 l / min, preferably 0.2 l / min to 1.0 l / min, and particularly preferably 0.3 l / min to 0.7 l / min. Furthermore, it is preferred to direct the water to be supplied to the heating element pocket exclusively via the water supply line for cuff rinsing. All described advantages and features of the laundry treatment appliance can be transferred analogously to the use and vice versa.

[0048] Further advantages and features of the present invention will become apparent from the following description of preferred embodiments with reference to the accompanying figures. It is understood that individual embodiments shown in the respective figures may have features that may also be used in other embodiments, even if this is not explicitly stated and unless this has been explicitly excluded due to technical circumstances.

[0049] They show: Fig. 1: a schematic cross-section of a laundry treatment appliance according to an embodiment of the present invention viewed from a front view; Fig. 2: a schematic cross-section AA from Fig. 1; Fig. 3: a schematic and perspective view of a sight glass according to an embodiment of the present invention; Figs. 4-6: schematic views of valve assemblies according to embodiments of the present invention; Fig. 7: a perspective view of a water supply line according to an embodiment of the present invention; and Fig. 8: a flow diagram of an embodiment of the present invention.

[0050] The figures explained below are not to scale and serve primarily to illustrate the inventive concept.

[0051] Fig. 1shows a schematic cross-section of a laundry treatment appliance 1 according to an embodiment of the present invention, viewed from the front. The laundry treatment appliance 1 shown comprises a tub 2 and a drum 5 rotatably arranged in the tub 2. Laundry can be added to and removed from the drum 5 via an opening in the tub 2 and the drum 5, which opening can be closed by a door 6. In addition, the laundry treatment appliance 1 has a treatment agent container 15 with a main wash chamber 16 and a pre-wash chamber 17. In the present embodiment, the laundry treatment appliance 1 is designed such that water can be directed to the drum 5 via a first water outlet 18, which is connected to the main wash chamber 16, via a main water inlet 30.Water can be supplied to the water supply line 8 via a second water outlet 19, which is connected to the pre-wash chamber 17 of the treatment agent container 15. The water supply line 8 is designed to direct the water to a sight glass 7 of the door 6. The sight glass 7 is designed such that the water can be directed, bypassing the drum 5, to a heater pocket 3, in which a heater 4 is arranged. There, the water can be heated by the heater 4, thereby generating steam. The heater pocket 3 is in fluid communication with the tub 2, via which the steam can enter the drum 5. The flow or volume flow of water that is directed through the water supply line 8 is controlled by a control unit 9 (not shown).By setting a sufficiently low volume flow, it can be prevented that the water which is passed through the sight glass 7 enters the drum 5 and possibly unintentionally moistens the laundry.

[0052] Fig. 2 shows a schematic view of a cross-section through the Fig. 1drawn section line AA. In this embodiment, the laundry treatment appliance 1 comprises a control unit 9, which controls the volume flow of water via a first valve 12, which is fed via the treatment agent container 15 into the water supply line 8. The laundry treatment appliance 1 further comprises a second valve 13 and a third valve 14, both of which are also controlled by the control unit 9. The valves are connected in parallel, i.e. in particular not one after the other. By means of a water supply 20, water is fed through one or more of the three valves, provided the corresponding valve is open. The second valve 13 serves to supply water to the main wash chamber 16. Both the first valve 12 and the third valve 14 feed the water into the pre-wash chamber 17 of the treatment agent container 15, for which purpose the outlets of these two valves 12, 14 are brought together by means of a Y-piece 25.This advantageously allows the water flow rate and / or water quantity to be adapted to the selected program. In particular, the valves can be designed such that the first valve 12 allows only a low water flow rate for a steaming program, while the third valve 14 allows a larger water flow rate for a pre-wash program. In both cases, the water is conducted via the existing path via the pre-wash chamber 17. The treatment agent container 15 can preferably be designed such that it directs water from the pre-wash chamber 17 exclusively into the water supply line 8, which leads to the sight glass 7, in particular if the volume flow rate supplied to the pre-wash chamber 17 is sufficiently low that the water does not reach the main water inlet 30 of the main wash program to the drum 5.

[0053] Fig. 3shows a perspective view of the sight glass 7 of the door 6, wherein the sight glass 7 is conical in this embodiment. The cone is directed towards the drum 5. Via the water supply line 8 (not shown in Fig. 3), which is located above the sight glass 7, water is directed onto a casing surface 21 of the conical sight glass 7 as part of the vaporization function. The water is then passed through the sight glass 7 to a sealing sleeve 10, as indicated by arrows, for example in the form of a trickle along the casing surface 21. It is conceivable for the casing surface to have a contour designed in such a way that it can specifically direct the water downwards towards a sealing sleeve 10. The water thus runs along the sight glass 7 without entering the drum 5. Openings 11 are arranged in the lower area near or on the sealing sleeve 10. The sealing sleeve 10 and the openings 11 are designed and / or arranged in such a way that the water is drained into a sleeve gap 31 between the folds of the sealing sleeve 10 and from there via the openings 11. From there the water flows into the radiator pocket 3.Furthermore, steam generated from the water by the heater 4 can be directed upwards and into the drum 5 via the openings 11. In other words, the volume flow is adjusted by the control unit 9 such that the water is directed exclusively to the heater pocket 3 via the sight glass 7. Thus, using a cuff flush, water can be supplied to the heater pocket 3 without entering the drum 5. Laundry in the drum 5 is therefore not directly moistened during the steaming program, and no water spots form on the laundry.

[0054] The Figures 4 to 6show various embodiments of valve assemblies 23 according to embodiments of the present invention. The valve assemblies 23 can be controlled by the control unit 9 via control connections 24. In principle, it is conceivable, for example, to use a valve 14 that is provided for the pre-wash program for the steaming function as well, if the valve 14 can be controlled by the control unit 9 according to the invention in such a way that a sufficiently low volume flow can be enabled. If, however, this prerequisite is not met, it is conceivable to provide an additional valve 12 in the valve assembly 23. According to one embodiment, the water that is passed through both valves, namely the first valve 12 and the third valve 14, is passed into the pre-wash chamber 17 of the treatment agent container 15, from where it can reach the water supply line 8.For this purpose, it may be useful to install a Y-piece 25 designed to direct the water from both valves along the same path into the pre-wash chamber 17. The Y-piece 25 can be arranged as shown in . Fig. 4 shown, be part of a connecting hose 22, which can be designed to connect the valve arrangement 23 with the pre-wash chamber 17 of the treatment agent container. In the Fig. 5 In the embodiment shown, the Y-piece is an integral part of the valve arrangement 23, whereas the Y-piece in the embodiment of Fig. 6 attached to the valve assembly 23.

[0055] Fig. 7shows a final section 26 of the water supply line 8 according to an embodiment of the present invention. This is designed such that water which reaches the final section 26 through a water inlet 27 is guided through the water outlet 28 onto the sight glass 7 of the door 6. If the volume flow is sufficiently low, the water drips over the lip 29 in a defined manner onto the sight glass 7, in particular onto a casing region 21 of the sight glass 7. The lip 29 can ensure that water discharged from the water supply line 8 impacts the casing region 21 of the sight glass 7 in a targeted manner (i.e. in a defined manner). The lip 29 can in particular reduce the flow velocity of the escaping water. This prevents water from getting into the drum 5.

[0056] Fig. 8shows a method 100 according to the invention for steaming laundry in the laundry treatment appliance 1 in the form of a flow chart. In a first method step 101, a laundry treatment appliance 1 according to one of the previously described embodiments is provided. The next step 102 comprises controlling a volume flow of water that is fed to the water supply line 8. The water is supplied to the heating element pocket 3, bypassing the drum 5, by being guided through the water supply line 8 onto the sight glass 7 of the door and along the sight glass 7. In particular, the water can preferably be guided over a jacket region 21 of a conical sight glass 7. Finally, in step 102, the water is heated by the heating element 4 placed in the heating element pocket, so that the generated steam flows into the drum 5. Reference symbol

[0057] 1 Laundry treatment appliance 2 Soil container 3 Radiator pocket 4 Radiator 5 Drum 6 Door 7 Sight glass 8 Water supply line 9 Control unit 10 Sealing sleeve 11 Openings 12 First valve 13 Second valve 14 Third valve 15 Treatment agent container 16 Main wash chamber 17 Pre-wash chamber 18 First water outlet 19 Second water outlet 20 Water supply 21 Jacket area 22 Hose 23 Valve assembly 24 Control connection 25 Y-piece 26 Final section of the water supply line 27 Water inlet 28 Water outlet 29 Lip 30 Main water inlet 100 Procedure 101-103 Procedure steps

Claims

1. Laundry treatment device (1) with a steaming function, wherein the laundry treatment device (1) has: an outer tub (2) which comprises a heating element recess (3) with a heating element (4) accommodated therein, a drum (5) which is rotatably arranged in the outer tub (2), a door (6) for closing off an aperture of the outer tub (2), via which the drum (5) is accessible, wherein the door (6) has a window (7) protruding towards the drum (5) and wherein the heating element recess (3) lies lower than the door (6) in an operating position of the laundry treatment device (1), a water supply line (8) which is configured to supply water to the heating element recess (3), wherein the water supply line (8) is positioned in the outer tub (2) such that the water to be supplied to the heating element recess (3) can run over the protruding window (7), and a control unit (9) which is configured to control a volume flow of the water to be supplied to the heating element recess (3) through the water supply line (8), such that the water along the protruding window (7) bypasses the drum (5) and can be conducted into the heating element recess (3) so that the volume flow is controlled to a value in a range from 0.1 l / min to 2.0 l / min, preferably 0.2 l / min to 1.0 l / min and particularly preferably 0.3 l / min to 0.7 l / min.

2. Laundry treatment device (1) according to claim 1, wherein the protruding window (7) of the door (6) is designed as a cone-shaped projection in the direction of the drum (5), wherein the water supply line (8) is arranged such that the water can be conducted onto the casing region (21) of the projection, in particular onto a region which is nearer the beginning of the projection than the end of the projection which projects into the drum (5).

3. Laundry treatment device (1) according to claim 2, wherein the projection has a contour which is configured to discharge the water to be supplied to the heating element recess (3) in a defined manner over the projection by bypassing the drum (5).

4. Laundry treatment device (1) according to one of the preceding claims, wherein the outer tub (2) has a sealing sleeve (10) which seals the aperture of the outer tub (2) together with the door (6) when the door (6) is in the closed position, and wherein apertures (11) are arranged on or at the sealing sleeve (10), by way of which apertures water discharged on the projection can be supplied directly to the heating element recess (3).

5. Laundry treatment device (1) according to one of the preceding claims, wherein the control unit (9) is designed to open and close a first valve (12) arranged upstream of the water supply line (8), in order to control the volume flow of the water to be supplied to the heating element recess for the steaming function.

6. Laundry treatment device (1) according to claim 5, wherein the laundry treatment device (1) further comprises a second valve (13) and a third valve (14), wherein the second valve is configured to supply water for a main wash cycle to the outer tub (2), wherein the third valve is configured to supply water for a prewash cycle to the outer tub (2) via the water supply line (8).

7. Laundry treatment device (1) according to one of the preceding claims, wherein the laundry treatment device (1) comprises a treatment agent container (15), which is arranged upstream of the water supply line (8), wherein the treatment agent container (15) has a main wash chamber (16) for a treatment agent for use during a main wash cycle, and a prewash chamber (17) for a treatment agent for use during a prewash cycle, wherein the treatment agent container (15) is configured such that the water to be supplied directly to the heating element recess (3) for the steaming function can be conducted through the prewash chamber (17).

8. Laundry treatment device (1) according to claim 7, wherein the treatment agent container (15) has a first water outlet (18) and a second water outlet (19), wherein the first water outlet (18) is configured to supply the water to the drum (5), and wherein the second water outlet (19) is configured to supply water to the water supply line (8).

9. Method (100) for steaming laundry in a laundry treatment device (1), wherein the method comprises: providing a laundry treatment device (1) according to one of the preceding claims, controlling a volume flow of water fed by the water supply line (8), such that the water is supplied to the heating element recess (3) by bypassing the drum (5), wherein the water is conducted over the window (7) through the water supply line (8), such that the volume flow is controlled to a value in a range from 0.1 l / min to 2.0 l / min, preferably 0.2 l / min to 1.0 l / min and particular preferably 0.3 l / min to 0.7 l / min, and heating the water in the outer tub (2) by way of the heating element (4) accommodated in the heating element recess (3), such that the steam generated flows into the drum (5).

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