Washing machine with pump system and method for its operation

Abstract

The invention relates to a washing machine with a tub, a drum arranged therein for receiving laundry items, a heating device, a drive motor, a water supply device, and a control device, wherein the pumping system comprises a pump housing 1 with a discharge port 2, a transfer port 3, and a suction port 4, wherein a discharge motor 5, a transfer motor 6, and an openable screw cap 7, to which a substantially cylindrical filter insert 8, removable from the washing machine and having at least one opening 9 along its circumference for the passage of an aqueous liquid, are arranged on the pump housing 1, such that the pump housing 1 comprises a substantially cylindrical suction chamber 10, a discharge pressure chamber 11, and a transfer pressure chamber 12, and wherein the discharge motor 5 is arranged such thatto convey an aqueous liquid from the substantially cylindrical suction chamber 10 through the filter insert 8 via the discharge pressure chamber 11 and the discharge nozzle 3 into a discharge line, and the transfer pump motor 6 is arranged to convey the aqueous liquid from the substantially cylindrical suction chamber 10 through the filter insert 8 via the transfer pressure chamber 12 and the transfer nozzle 3 into a transfer line, wherein the substantially cylindrical filter insert 8 has at a first end 15 the removable closure 7, at a second end 16 a discharge seal 17 for sealing the discharge pressure chamber 11 against the substantially cylindrical suction chamber 10, and on its circumference has a transfer opening 9 to the transfer pressure chamber 12, wherein the circumference has a shield 18 enclosing the transfer opening 9,which is surrounded by a labyrinth seal 20 and seals the recirculation pressure chamber 12 against the suction chamber 10. The invention also relates to a method for operating this washing machine.

Description

[0001] The invention relates to a washing machine with a pumping system and a method for operating the same. The invention particularly relates to a washing machine with a tub, a drum arranged therein for holding laundry items (laundry items), a heating device, a drive motor, a water supply device, and a control or regulating device. The pumping system comprises a pump housing with a pumping nozzle, a pumping nozzle, and a suction nozzle. A pumping motor, a pumping motor, and an openable screw cap are arranged on the pump housing. A substantially cylindrical filter insert is attached to the pump housing and has at least one opening along its circumference for the passage of an aqueous liquid. The filter insert is removable from the washing machine and has at least one opening for the passage of an aqueous liquid. The pump housing comprises a substantially cylindrical suction chamber, a pumping pressure chamber, and a pumping pressure chamber. The pump motor is arranged such thatto convey an aqueous liquid from the substantially cylindrical suction chamber via the pumping pressure chamber and the pumping nozzle into a pumping line, and the pumping motor is arranged to convey the aqueous liquid from the substantially cylindrical suction chamber via the pumping pressure chamber and the pumping nozzle into a pumping line.

[0002] There are an increasing number of washing machines that allow heavier loads of laundry. In order to better adapt the washing processes to the increased laundry loads, modern large-volume washing machines are often equipped with a pumping system that transports the washing solution better and, above all, more quickly into the laundry items. Rinsing the washing solution during the rinsing phase can be done faster and more efficiently. Finally, due to the new washing appliance label requirements (EN19) with regard to washing performance and energy efficiency, large-volume washing machines are now equipped with a pumping system. This means that low washing solution levels can be achieved in the washing machine or in the suds container for the washing process. This means that even with low water levels in the suds container and therefore with low heating output from an existing heating device, the washing solution can be quickly brought to the desired washing process temperature in order to meet the label requirements, for example.This can be achieved, for example, with regard to energy consumption. A pumping system allows washing liquor to be pumped into the laundry even at liquid levels in the tub where watering the laundry would not be possible without a circulation system. This is because the drum is not yet immersed in the "dead liquor" (washing liquor in the tub) at such low liquid levels, and thus watering of the laundry through a diffusion process from the outside to the inside of the laundry is not possible.

[0003] The publication DE 10 2016 210 320 A1 describes a method for operating a washing machine with a tub, a drum arranged therein for receiving laundry items, a drive motor, at least one water supply device, generally for supplying water into the tub, a pumping system with a drain pump and a pumping line, and a control device in which at least one operating program is stored.

[0004] Publication DE 10 2018 206 364 A1 describes a household appliance for washing laundry, comprising a tub in which a laundry drum designed to hold the laundry items is arranged, and a pumping system comprising a circulation pump by means of which a fluid can be conveyed from a lower region of the tub. In one embodiment, the pumping system comprises a drain pump, wherein the circulation pump and the drain pump are arranged in a common pump housing of the pumping system. In a further embodiment, an inlet-side chamber of the pump housing has a closure element, wherein after opening the closure element, the filter device is accessible for maintenance and / or can be removed from the chamber.

[0005] Publication DE 10 2016 212 478 A1 describes a laundry care appliance with a pumping system comprising a suction chamber, wherein the pump has a filter and / or foreign body trap for filtering impurities from the washing liquid, and wherein the suction chamber has a filter insertion opening for inserting the filter into the suction chamber. The filter has a filter insert arranged within the suction chamber and a filter cover designed to seal the filter insertion opening in a fluid-tight manner.

[0006] Publication CN 108 729 148 A describes a washing machine with a tub, a drum arranged therein for holding laundry items, a heating device, a pumping system, a drive motor, a water supply device and a control or regulating device, wherein the pumping system comprises a pump housing with a pumping nozzle, a pumping nozzle and a suction nozzle, wherein a pumping motor, a pumping motor and an openable screw cap, to which a cylindrical filter insert which can be removed from the washing machine and has at least one opening along its circumference for the passage of an aqueous liquid, are arranged on the pump housing, so that the pump housing comprises a cylindrical suction chamber, a pumping pressure chamber and a pumping pressure chamber, and wherein the pumping motor is arranged,to convey an aqueous liquid from the substantially cylindrical suction chamber through the filter insert via the pumping pressure chamber and the pumping nozzle into a pumping line, and the pumping motor is arranged to convey the aqueous liquid from the cylindrical suction chamber through the filter insert via the pumping pressure chamber and the pumping nozzle into a pumping line, wherein the substantially cylindrical filter insert has the openable screw cap at a first end, a pumping seal at a second end for sealing the pumping pressure chamber from the cylindrical suction chamber, and a pumping opening to the pumping pressure chamber on its periphery, wherein the periphery has a shield enclosing the pumping opening, which is surrounded by a labyrinth seal and seals the pumping pressure chamber from the suction chamber.

[0007] Publication EP 3 508 647 A1 describes a washing machine comprising a tub for holding water; a water supply valve for regulating a water supply line through which the water is supplied; a detergent container from which detergent is supplied into the tub with the water supplied through the water supply line; a drum rotatably arranged in the tub; a spiral pump configured to pump water discharged from the tub and rotating in two directions, wherein the spiral pump discharges a larger amount of water when the impeller rotates in a forward direction than when it rotates in a reverse direction; a circulating water supply device configured to spray the water discharged from the outlet opening into the drum; and a processor configured to control the spiral pump, the processor further configured tothat it opens the water supply valve so that water is supplied up to a predetermined water level in the tub, and controls the spiral pump so that the spiral pump rotates in the reverse direction. Preferably, the spiral pump comprises an impeller configured to pump water; and a brushless direct current (BLDC) motor configured to rotate the impeller. Pumping systems, also known as circulation pump systems, usually consist of a drain pump and a circulation pump, which are usually combined in a common pump housing. The pump housing is usually designed so that both pumps draw from a common suction chamber, which incorporates either a foreign body trap or a lint filter.To filter out foreign matter and / or lint from the suction-side flow and to partially enable access to the impellers of the pump-out motor and the transfer motor, so that potential impeller blockages caused by foreign matter can be removed by the customer. The discharge pump is usually arranged in an axial orientation, while the transfer pump is usually positioned radially. The geometric arrangement of the two pumps on the shared suction chamber is preferably designed to provide access to the impeller of the pump-out motor. This access should be very well sealed. The axially arranged pump housing is usually closed and sealed axially with a screw cap. Furthermore, the axial screw connection simultaneously axially preloads the filter insert integrated in the suction chamber so thatthat a good seal can be achieved between the discharge pressure chamber and the suction chamber with regard to the discharge pump. This seal must be particularly reliable for the discharge pump, as there are VDE requirements specifically for the discharge pump regarding flow rate and flow rate maintenance over the service life of the washing machine.

[0008] However, the radially arranged pressure chamber of the circulation pump (recirculation pressure chamber) must be sealed against the suction chamber. This is because a gap generally results between a removable filter insert and the pump housing, even if attempts are made to keep this gap as small as possible during manufacturing. This gap is a result of the production of the pump housing and filter insert, which are usually manufactured by injection molding, where certain tolerances are specified. If such a seal is not implemented, this can lead to significant leakage, which can make controlling a wash program, and in particular controlling the circulation of aqueous liquid in a recirculation system, very difficult or even impossible. The flow of aqueous liquid should preferably occur at a certain speed and at a certain angle into the drum.Furthermore, the hydraulic separation of the suction chamber from the pumping pressure chamber cannot be optimally utilized for the further development of improved washing processes in terms of the hydraulically adjustable operating point and potential foreign matter adhesion, because the simple gap seal results in excessive leakage. The leakage should be as low as possible across the aforementioned system-specific gap.

[0009] Against this background, the object of the present invention was to provide a washing machine with a pumping system which is particularly suitable for large loads of laundry items, wherein an improved control of the pumping system can achieve a better flow of an aqueous liquid, in particular washing liquor, through the laundry items and an improved cleaning of laundry items can be carried out.

[0010] This object is achieved according to the invention by a washing machine and a method for operating this washing machine having the features of the corresponding independent patent claims. Preferred embodiments of the washing machine according to the invention are listed in the respective dependent patent claims. 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.

[0011] The subject of the invention is a washing machine with a tub, a drum arranged therein for holding laundry items, a heating device, a pumping system, a drive motor, a water supply device and a control or regulating device, wherein the pumping system comprises a pump housing with a pumping nozzle, a pumping nozzle and a suction nozzle, wherein a pumping motor, a pumping motor and an openable screw cap, to which a filter insert which can be removed from the washing machine is attached and which has at least one opening along its circumference for the passage of an aqueous liquid, are arranged on the pump housing, so that the pump housing comprises a substantially cylindrical suction chamber, a pumping pressure chamber and a pumping pressure chamber, and wherein the pumping motor is arranged such thatto convey an aqueous liquid from the substantially cylindrical suction chamber via the pumping pressure chamber and the pumping nozzle into a pumping line, and the pumping motor is arranged to convey the aqueous liquid from the substantially cylindrical suction chamber through the filter insert via the pumping pressure chamber and the pumping nozzle into a pumping line, wherein the filter insert has the openable screw cap at a first end, a pumping seal at a second end for sealing the pumping pressure chamber from the substantially cylindrical suction chamber, and on its circumference, usually orthogonal thereto, a pumping opening to the pumping pressure chamber, wherein the circumference has a shield enclosing the pumping opening, which is surrounded by a labyrinth seal and seals the pumping pressure chamber from the suction chamber, wherein the shield has a connecting region,by which the shield is directly or indirectly connected to the first end of the cylindrical filter insert. Preferably, the shield is surrounded by a labyrinth seal outside a connection area. Generally, the shield is connected to the rest of the filter insert via a connection area for stabilization.

[0012] The at least one opening along the circumference of the filter insert is therefore the circulation opening. The filter insert is generally designed to have three openings for the passage of an aqueous fluid, namely one on the suction side and two on the pressure side to feed the circulation pump and the discharge pump, i.e., one inlet from the suction chamber and two outlets or outlets to the pressure chambers. While the pump housing is generally almost cylindrical, except for draft angles, the filter insert does not necessarily have to be cylindrical in its external geometry.

[0013] According to the invention, a pump housing is used that combines both the pumping and transfer functions. This enables a particularly compact design of the transfer system and a comparatively low installation space requirement. Such a housing is particularly suitable for production using plastic injection molding.

[0014] A removable filter insert can be detachably attached to the screw cap, which can be opened and removed from the washing machine. It is generally possible for the cap and filter insert to be designed as a single piece, for example, manufactured as a one-piece injection-molded part. However, simultaneous sealing of the pumping and discharge pressure chambers may be difficult or even impossible due to functional constraints, as the molded-on filter insert would then have to rotate when the cap is screwed on, preventing this labyrinth seal from working.

[0015] In a pumping phase, the aqueous liquid is transported from the essentially cylindrical suction chamber via the pumping pressure chamber and the pumping nozzle into a pumping line, which in turn is connected to an inlet into the drum, so that the pumped aqueous liquid ultimately reaches the laundry items in the drum again.

[0016] The control or regulating device is generally designed to cause the aqueous liquid to be pumped around or pumped out.

[0017] The filter insert is, in the broadest sense, a cylindrical filter insert in which its external dimensions or geometry are designed to allow unhindered insertion into the essentially cylindrical suction chamber and correspondingly unhindered removal by a washing machine user. The filter insert generally has components that contribute to the mechanical stabilization of the filter insert itself and enable fixed positioning in the cylindrical suction chamber. While the pump housing is almost cylindrical apart from draft angles, the filter insert's external geometry does not necessarily have to be cylindrical.

[0018] In a pumping phase, however, the aqueous liquid is transported from the cylindrical suction chamber via the pumping pressure chamber and the pumping nozzle into a pumping line, which is generally connected to a sewage system, so that the pumped aqueous liquid can be disposed of.

[0019] The shield serves the purpose of providing improved sealing between the pumping pressure chamber and the suction chamber and is also intended to provide access to the pumping pressure chamber and thus also to the impeller of the pump. The shield is therefore generally adapted to the shape of the pumping pressure chamber to enable good flow guidance. In a preferred embodiment of the washing machine according to the invention, the shield is therefore concavely shaped to seal a convex pumping pressure chamber from the cylindrical suction chamber. The shield can thus be concavely shaped to seal a convex pumping pressure chamber.

[0020] According to the invention, the shield for closing or sealing the pumping pressure chamber is surrounded on its circumference by a labyrinth seal, in particular outside a connection area. The labyrinth seal is generally a non-contact seal in which the sealing effect is based on the extension of the flow path, i.e. usually by a flow deflection, through the gap to be sealed, whereby the flow resistance is significantly increased. This can be achieved, for example, by providing one or more stages along the flow path, in this case the aqueous liquid, so that the flow is deflected several times within the labyrinth seal (or stage seal). The labyrinth seal preferably has at least one stage, more preferably two or three stages.

[0021] According to the invention, the generally circumferential gap between the filter insert and the pump housing is widened such that this gap is covered by the shield, which can also be referred to as a collar or overlap, on the filter insert and, if necessary, a complementary counterpart on the filter housing. This generally radially pronounced shield above the axially extending gap is preferably located as parallel as possible to a developing, radially building pressure gradient in the pumping pressure chamber. The filter insert used according to the invention causes a significant flow deflection for the leakage flow, resulting in an increased pressure loss, which enables a reduction in the leakage flow.

[0022] According to the invention, a washing machine is preferred in which the angle α between a pumping motor shaft and a filter insert axis is in the range of > 0° to 30°, for example, in the range of 3° to 15°. It is particularly preferred that the angle α is selected such that the static friction between the generally used disc spring of the filter insert, i.e., the sealing element for the pumping pressure chamber, and the pump housing is eliminated.

[0023] This embodiment of the present invention enables the sealing achieved by the shield, according to the invention, to be further improved by applying axial contact pressure to the pumping seal, particularly when the latter is designed as a disc spring. This is because the filter insert "slides" along the partition wall to the pumping pressure chamber, allowing the shield on the filter insert to better seal the pumping pressure chamber, thereby more effectively closing the gaps inherent in the design. This allows for a higher pressure loss, which further constricts or limits the leakage flow. To achieve such a contact force for better sealing of the pumping pressure chamber, the filter insert can be clamped axially against the pump housing with respect to the pumping pump or pumping motor in such a way that radial sliding of the filter insert toward the suction chamber is possible.This sliding of the filter insert along the boundary wall of the pump housing toward the discharge pressure chamber can be achieved in particular if the angle α between a discharge motor shaft and a filter insert axis is in the range of 3° to 15°. However, the selected angle α depends on the materials used, for example, whether plastics meet or metal meets plastic. If the self-locking (static friction) between the filter insert and the pump housing is eliminated, the filter insert in the suction chamber, i.e., in the pump housing, can press radially against the pumping pressure chamber to seal it as best as possible.

[0024] Likewise, a washing machine according to the invention is preferred in which the angle β between a pumping motor shaft and a filter insert axis is in the range of 70° to 110°, and preferably in the range of 85° to 95°.

[0025] Preferably, the pumping seal is a disc spring, which generally acts axially to seal an axially or quasi-axially arranged pressure chamber of the pump, i.e., the pumping motor. In embodiments of the invention in which the axial seal between a common suction chamber and the pumping pressure chamber is achieved by elastic deformation of a disc spring on the filter insert, the invention enables a novel, structural sealing principle for sealing the pumping pressure chamber, which is generally arranged radially on the common suction chamber of the pumping system and is partially accessible to the user, in order to minimize leakage flows, i.e., a hydraulic short circuit from the pressure to the suction chamber, which requires double conveyance of the leakage flow between the pump housing and the pump filter insert.

[0026] The filter insert can, in principle, be designed as a lint filter and / or as a foreign body trap. The filter insert as a lint filter can be designed like a sieve, which serves in particular to retain hair, lint, and the like. Additionally or alternatively, the filter insert can be designed as a foreign body trap, which serves to retain larger foreign bodies such as coins, hair clips, or similar small items.

[0027] In a preferred embodiment of the invention, the filter insert is designed as a foreign body trap. In another preferred embodiment of the invention, a lint filter is installed upstream of the suction chamber.

[0028] Furthermore, a washing machine is preferred in which the filter insert has at least one guide bar parallel to the filter insert axis. This enables stable, fixed positioning of the filter insert, which contributes to optimal sealing between the pumping pressure chamber and the suction chamber.

[0029] Pump-out motors and transfer motors are generally electric motors. It is preferred that the pump-out motor and the transfer motor each be a brushless direct current (BLDC) motor, for example. These variable-speed and direction-of-rotation drives allow the current pump status to be determined through the control-dependent recording of operating parameters such as speed and torque. This makes it possible to detect, for example, whether a pump in use is pumping the full flow rate or has sucked in air, whether the flow rate has broken off and the pump has only built up a pressure column and is therefore essentially in suction-side aerated operation. This makes it possible to determine when the pump-out motor is pumping two-phase wash liquor with reduced density at a constant, reduced power requirement.

[0030] Finally, a washing machine with a larger intake port diameter than the drain port and the return port is preferred. However, the dimensions and diameter ratios can also be different.

[0031] A washing machine according to the invention has a heating device. In a preferred embodiment of the washing machine according to the invention, the washing machine has a heating device for heating the aqueous liquid and a temperature sensor for measuring the temperature of the aqueous liquid in the tub. The heating device is generally arranged in the lower part of the tub. Alternatively, the heating device can be integrated into the water paths of the pumping system, for example in the pump or in the pressure-side pumping line or an air duct circuit or a steam unit of the washing machine. This has the advantage that the space for the heating device can be eliminated in the tub, thereby reducing the free liquor or dead liquor in the tub. As a result, the amount of aqueous liquid required to treat the laundry items can be advantageously reduced, in order to, among other things,It also allows for less heating energy to be used to achieve comparable temperature levels. The heating device and the temperature sensor can be controlled and evaluated by the control unit, enabling temperature control.

[0032] The water supply device can, for example, be a time-valve-controlled fresh water connection, with the valve preferably being controllable by the control device. Particularly preferably, the fresh water supply line to the tub additionally includes a flow sensor for determining the volume of fresh water introduced. By additionally detecting the fill level in the tub using a pressure sensor, the water supply for the laundry load in use can be precisely specified or adjusted.

[0033] In a further preferred embodiment of the washing machine according to the invention, the washing machine additionally has a load sensor for determining the mass of laundry items in the drum. The load sensor is advantageously located on the tub and connected to the control device. Therefore, according to the invention, the control device preferably takes into account the load size and, if possible, the type of laundry load in the drum when controlling the pumping system.

[0034] The invention also relates to a method for operating a washing machine with a tub, a drum arranged therein for holding laundry items, a heating device, a pumping system, a drive motor, a water supply device, and a control or regulating device, wherein the pumping system comprises a pump housing with a pumping nozzle, a pumping nozzle, and a suction nozzle, wherein a pumping motor, a pumping motor, and an openable screw cap, to which a substantially cylindrical filter insert is attached and which can be removed from the washing machine and has at least one opening along its circumference for the passage of an aqueous liquid, are arranged on the pump housing, so that the pump housing comprises a substantially cylindrical suction chamber, a pumping pressure chamber, and a pumping pressure chamber, and wherein the pumping motor is arranged such thatto convey an aqueous liquid from the substantially cylindrical suction chamber through the filter insert via the pumping pressure chamber and the pumping nozzle into a pumping line, and the pumping motor is arranged to convey the aqueous liquid from the substantially cylindrical suction chamber through the filter insert via the pumping pressure chamber and the pumping nozzle into a pumping line, wherein the substantially cylindrical filter insert has the removable closure at a first end, a pumping seal at a second end for sealing the pumping pressure chamber from the cylindrical suction chamber, and a pumping opening to the pumping pressure chamber at its periphery, wherein the periphery has a shield enclosing the pumping opening, which is surrounded by a labyrinth seal and seals the pumping pressure chamber from the suction chamber, wherein the shield has a connecting region,via which the shield is connected directly or indirectly to the first end of the cylindrical filter insert, comprising the steps of (a) controlling the pumping motor and / or the transfer motor by the control device such that one of these motors is switched on, i.e. activated or controlled; (b) sucking an aqueous liquid into the suction chamber by means of the controlled pumping motor or the controlled transfer motor; and (c1) conveying the aqueous liquid from the substantially cylindrical suction chamber through the filter insert via the transfer pressure chamber and the transfer nozzle into the transfer line; or (c2) conveying the aqueous liquid from the substantially cylindrical suction chamber via the pumping pressure chamber and the pumping nozzle into the pumping line.

[0035] Generally, the aqueous liquid is conveyed into the domestic sewage system after step (c2).

[0036] In a preferred embodiment of the method according to the invention, the control or regulating device is designed to take into account the load of laundry items.

[0037] The circulation motor of the circulation system is generally only switched on after the introduction of aqueous liquid, in particular water, has begun, in particular after a first predetermined volume V Start of water has been introduced into the suds container. The aqueous liquid can be fresh water or process water, which can be stored in the washing machine, for example, in the form of grey water, or a mixture of fresh water and grey water. Grey water is understood to be wastewater that is slightly polluted. For example, the liquid from the last rinse cycle of a washing machine treatment program could not be pumped into the wastewater line, but rather temporarily stored in an optional container in the washing machine. In a subsequent treatment program, the temporarily stored liquid could be rinsed into the suds container at the beginning of a pre-treatment phase.This has the advantage of saving fresh water, which saves resources for treating the laundry items. In a preferred embodiment of the method according to the invention, fresh water is supplied to the tub.

[0038] Preferably, the aqueous liquid is pumped out at the bottom of the tub and returned to a point as central as possible in the drum or tub, so that the laundry items in the drum are contacted centrally with the returned aqueous liquid. A so-called laundry tunnel can be specially formed for this injection process, into which the water is then injected centrally in a way that optimizes watering. The point at which the pumped-over treatment liquid is fed to the tub is referred to herein as the tub inlet. Alternatively, the treatment liquid can be returned directly into the drum and onto the laundry items. In this alternative case, the tub inlet can be located in the area of ​​a loading opening in the drum. A rear feed is also conceivable, for example by feeding the aqueous medium through a hollow drive shaft.

[0039] In a preferred embodiment of the method according to the invention, the pumping system, preferably in the control or regulating device, comprises a pumping control unit. The pumping control unit detects a pumping motor power P and evaluates this with regard to the density, degree of linting, and two-phase nature of the medium to be pumped, the presence of foreign bodies in the pumping line, and / or the contamination of a filter present in the pumping line. In this case, a relationship between the pumping power and various contamination states, e.g., of a filter used, is preferably stored in the pumping control unit and / or the control device of the washing machine.

[0040] The invention offers numerous advantages. It makes it possible to achieve excellent hydraulic separation between the suction and pressure sides of the circulation pump of the pumping system without requiring an additional, costly sealing element on the filter insert. Furthermore, good accessibility and visibility of the impeller of the usually radially arranged circulation pump can be achieved on the pump housing. The filter insert can be easily removed by a washing machine user for cleaning purposes.

[0041] With a one-dimensional gap design, manufacturing tolerances have a significant influence on the functional design of the leakage flow. By creating the housing gap between the pump housing and the filter insert in axial and radial dimensions, as achieved with the invention, and by appropriate centering, the sealing effect can be virtually independent of the manufacturing tolerances of a one-dimensional gap design.

[0042] Tool manufacturing costs can be lower if less attention is paid to maintaining radial gap geometries. This is particularly important when multiple tools or multiple tool cavities (tool nests) are used in one tool to cover part requirements, for which separate tool costs are then incurred to minimize the variance between the tools with regard to leakage current. In this regard, the invention results in longer tool maintenance cycles, during which, with a one-dimensional gap design, the disruptive gap or leakage currents must be repeatedly monitored and limited, since the filter insert used according to the invention is less sensitive in this regard and therefore requires less maintenance.

[0043] In the embodiment of the invention, in which a contact pressure is additionally implemented to better close the pumping pressure chamber, a complex tolerance analysis is almost unnecessary, since the sealing principle is based on a seal that acts almost over a large area and not, as in the original one-dimensional gap design, only a line contact, which is very susceptible to tolerances in the components in its sealing effect.

[0044] The pumping system sealed according to the invention can be more reliable over its entire operating time (service life). For example, in the embodiment in which preload is applied to the dual (axial and radial) acting seal, not only can manufacturing tolerances be larger, but relaxation processes in the plastics for the filter insert or the pump housing, which occur over the service life due to thermal cycling, can be counteracted. Radial ribbing on the suction side of the filter insert shield, which closes off the pumping pressure chamber and even extends beyond the sealing collar, can influence this effect even more positively, thus guaranteeing consistently low leakage currents over the entire operating time and ensuring that the main functions of pumping out and pumping over the service life of the washing machine continue to function properly.

[0045] An additional positive side effect is that the reduction in leakage between the pressure and suction chambers reduces the risk of lint buildup in the pumps over their operating life (service life). This is because lint that has already reached the pressure chamber is pumped out or recirculated more reliably, without being forced back into the suction chamber through the leakage and being exposed to double pumping, which poses a higher risk of lint buildup for the pumps. The more reliable sealing of the sealing gap makes it almost impossible for lint to adhere to the gap or seal geometry, which is significantly more risky with a one-dimensional gap seal, as experimental studies by the inventors have shown.

[0046] Non-limiting embodiments of the invention are explained in more detail below with reference to the accompanying drawings. Reference is made to the Figuren 1 bis 8 . They show: Fig. 1 is a perspective view of a pump housing used according to the invention with a pumping motor and a pumping transfer motor connected thereto; Fig. 2a) is a perspective view of a pumping / pumping-transfer motor with an impeller; b) is a side view of the pumping / pumping-transfer motor from a); Fig. 3a) is a perspective view of a filter insert used according to the invention; b) is a further perspective view of this filter insert used according to the invention; Fig. 4a) is a side view of a substantially cylindrical filter insert not used according to the invention, provided with an openable screw cap, in which a shield without a labyrinth seal is used; b) is a side view of a cylindrical filter insert provided with an openable screw cap in an embodiment used according to the invention, in which a shield with a labyrinth seal is used;Fig. 5: a vertical longitudinal section through a closure, a filter insert, the common suction chamber, and through the pressure chamber of the discharge pump; Fig. 6: a side view of a pumping system with a dismantled pumping motor to illustrate the gap geometry between the pump housing and the filter insert; Fig. 7: a sectional view through a pumping system in which the discharge pressure chamber has a relatively small angle α to the suction chamber in order to achieve an even better seal between the suction chamber and the pumping pressure chamber. Fig. 8: a labyrinth seal, in particular with a two-stage labyrinth seal shown on the left and a three-stage labyrinth seal shown on the right.

[0047] Fig. 1 shows a perspective view of a pump housing 1 used according to the invention with a discharge motor 5 and a transfer motor 6 connected to it. The pump housing has a discharge nozzle 2, a transfer nozzle 3, and an intake nozzle 4. Also arranged on the pump housing 1 is a removable closure 7, to which a cylindrical filter insert (not visible here) is attached. 10 denotes a suction chamber.

[0048] Fig. 2 shows in Fig. 2a a perspective view of a pumping / transfer motor 5,6 with an impeller 27 and Fig. 2b a side view of the pumping / transfer motor 5,6 of Fig. 2a , in which the shape of the impeller 27 is even more clearly visible.

[0049] Fig. 3a shows a perspective view of a filter insert 8 used according to the invention, to which a removable closure (not shown here) is generally attached at the left end, via which a user of the washing machine can remove the filter insert 8 from a washing machine (also not shown here). The filter insert 8 generally has a removable closure (not shown here) at a first end 15, a disc spring 17 as a pumping seal for sealing a pumping pressure chamber (not shown here) from a cylindrical suction chamber (also not shown here), and on its circumference a circular pumping opening 9 to the pumping pressure chamber (not shown), wherein the circumference has a shield 18 enclosing the pumping opening 9 and sealing the pumping pressure chamber from the suction chamber.The shield 18 has a connecting region 19, via which the shield 18 is directly or indirectly connected to the first end 15 of the cylindrical filter insert 8. Since the shield 18 here is part of the cylindrical filter insert formed by injection molding a plastic material, the connecting region 19 is an integrated plastic part. In this non-limiting embodiment, the shield 18 is concavely shaped to seal a convex pumping pressure chamber from a cylindrical suction chamber. Furthermore, the shield 18 is surrounded outside the connecting region 19 by a labyrinth seal 20 (not shown in detail here).

[0050] Fig. 3b shows another perspective view of the Fig. 3a shown filter insert, in which the filter insert 8 has a guide web 28 parallel to a filter insert axis 25 for better positioning.

[0051] Fig. 4a shows a side view of a filter insert 8 provided with a removable closure 7 (only indicated here), which is not used according to the invention, namely in which a shield 18 without a labyrinth seal is used. 17 denotes a disc spring, 9 a circular opening in the shield 18, and 19 a connecting area via which the shield 18 is connected to the second end 16 of the cylindrical filter insert 8. 28 denotes a guide web, and 15 the second end of the cylindrical filter insert 8.

[0052] Fig. 4b shows in comparison to Fig. 4a a side view of a substantially cylindrical filter insert provided with an openable screw cap in an embodiment used according to the invention, in which a shield with a labyrinth seal 20 is used.

[0053] Fig. 5 shows a vertical longitudinal section through a closure 7, a filter insert 8, the common suction chamber 10, and the pressure chamber 11 of the discharge pump. 28 denotes a guide bar, 12 the pumping pressure chamber, and 25 a filter insert axis. 27 denotes an impeller of the discharge motor 5. 2 denotes the discharge nozzle, and 24 the discharge motor shaft.

[0054] Fig. 6 shows a side view of a pumping system with a dismantled pumping motor to illustrate the gap geometry between the pump housing 1 and the filter insert 8. 7 denotes a removable closure, 10 a suction chamber, 4 a pumping nozzle, 2 the discharge nozzle, 5 a discharge motor, 25 a filter insert axis, 18 the shield, in which a circular opening 9 to the pumping pressure chamber 12 is arranged. 20 denotes a labyrinth seal around the shield 18.

[0055] Fig. 7 shows a sectional view through a pumping system in which the discharge pressure chamber 11 has a relatively small angle α to the suction chamber 10 in order to achieve an even better seal between the suction chamber 10 and the pumping pressure chamber 12. 17 denotes a disc spring, 18 a shield with an opening to the pumping pressure chamber 12 (not visible here). 29 denotes a resulting contact force, and 30 denotes axial clamping by a (screwable) closure cap 7. 8 denotes a filter insert.

[0056] The Fig. 7 The embodiment shown enables the filter insert 8 to slide radially relative to the common suction chamber 10 for better closing of the pumping pressure chamber 12. The plate spring 17 acts as a sealing element for the pumping pressure chamber. This embodiment enables the filter insert 8 to move away from the pumping pressure chamber 12 after axial tension has been released by unscrewing the filter cover 7. This has the effect that, although an additional resistance force is created when the filter insert 8 is inserted into the suction chamber 10, which presses the filter insert 8 against the sealing surface of the pumping pressure chamber 12, there is sufficient room for movement when the filter insert 8 is removed to prevent the filter insert 8 from jamming in the pump housing 1 when the filter insert 8 is removed if a user of the washing machine is forced to clean the pumping system for maintenance purposes.

[0057] Fig. 8 shows a labyrinth seal 20 in detail, whereby for illustration purposes this has a two-stage labyrinth seal 13 with two stages 21, 22 on the left and a three-stage labyrinth seal 14 with three stages 21, 22, 23 on the right. Bezugszeichenliste

[0058] 1 Pump housing 2 Pump out port 3 Pump transfer port 4 Suction port 5 Pump out motor 6 Pump transfer motor 7 Openable screw cap; removable end cap 8 Substantially cylindrical filter insert 9 Opening; pump transfer opening 10 Substantially cylindrical suction chamber 11 Pump out pressure chamber 12 Pump transfer pressure chamber 13 Two-stage labyrinth seal 14 Three-stage labyrinth seal 15 First end (of the substantially cylindrical filter insert) 16 Second end (of the substantially cylindrical filter insert) 17 Pump out seal; Disc spring 18 Shield 19 Connection area 20 Labyrinth seal 21 First stage of the labyrinth seal 22 Second stage of the labyrinth seal 23 Third stage of the labyrinth seal 24 Pump-out motor shaft 25 Filter insert axis 26 Pump-circulation motor shaft 27 Impeller of pump-circulation motor or pump-out motor 28 Guide web 29 Axial bracing by (screwable) sealing cap 30 Resulting contact force

Claims

1. Washing machine with an outer tub, a drum arranged therein for receiving items of laundry, a heating facility, a pump system, a drive motor, a water supply apparatus and a control or regulating facility, wherein the pump system comprises a pump housing (1) with a pump down connecting piece (2), a pump connecting piece (3) and an intake port (4), wherein a pump down motor (5), a pump motor (6), and a screw closure (7) to be opened, to which an essentially cylindrical filter insert (8) which can be removed from the washing machine is attached and which has at least one opening (9) for the passage of aqueous liquid along its periphery, are arranged on the pump housing (1), so that the pump housing (1) comprises an essentially cylindrical suction chamber (10), a pump down pressure chamber (11) and a pump pressure chamber (12), and wherein the pump down motor (5) is arranged so as to convey an aqueous liquid out of the essentially cylindrical suction chamber (10) through the filter insert via the pump down pressure chamber (11) and the pump down connecting piece (3) into a pump down line and the pump motor (6) is arranged in order to convey the aqueous liquid out of the essentially cylindrical suction chamber (10) through the filter insert via the pump down pressure chamber (12) and the pump connecting piece (3) into a pump line, wherein the essentially cylindrical filter insert (8) has the screw closure (7) to be opened at a first end (15), a pump down seal (17) for sealing the pump down pressure chamber (11) against the essentially cylindrical suction chamber (10) at a second end (16) and a pump opening (9) to the pump pressure chamber (12) at its periphery, characterised in that the periphery has a shield (18) enclosing the pump opening (9), said shield being surrounded by a labyrinth seal (20) and sealing the pump pressure chamber (12) against the suction chamber (10), wherein the shield (18) has a connection area (19), by way of which the shield (18) is connected directly or indirectly to the first end (15) of the cylindrical filter insert (8).

2. Washing machine according to claim 1, characterised in that the shield (18) is shaped to be concave, in order to seal a convexly formed pump pressure chamber (12) against the essentially cylindrical suction chamber (10).

3. Washing machine according to one of claims 1 to 2, characterised in that the labyrinth seal (20) has at least one stage (21, 22, 23), preferably two or three stages.

4. Washing machine according to one of claims 1 to 3, characterised in that the angle α between a pump down motor shaft (24) and a filter insert axis (25) is in the range of > 0° to 30°.

5. Washing machine according to claim 4, characterised in that the angle α is selected so that the friction between the filter insert (8) and the pump housing (1) is cancelled.

6. Washing machine according to one of claims 1 to 5, characterised in that the angle β between a pump motor shaft (26) and a filter insert axis (25) is in the range of 70° to 110°.

7. Washing machine according to one of claims 1 to 6, characterised in that the pump down seal (17) is a plate spring.

8. Washing machine according to one of claims 1 to 7, characterised in that a lint filter is arranged upstream of the suction chamber (8).

9. Washing machine according to one of claims 1 to 8, characterised in that the filter insert (8) is designed as a foreign body trap (8).

10. Washing machine according to one of claims 1 to 9, characterised in that the filter insert (8) has at least one guide web (28) parallel to a filter insert axis (25).

11. Washing machine according to one of claims 1 to 10, characterised in that the pump down motor (5) and the pump motor (6) is a brushless d.c. motor (BLDC) in each case.

12. Washing machine according to one of claims 1 to 11, characterised in that the intake duct (4) has a larger diameter than the pump down connecting piece (2) and the pump connecting piece (3).

13. Method for operating a washing machine with an outer tub, a drum arranged therein for receiving items of laundry, a heating facility, a pump system, a drive motor, a water supply apparatus, a control or regulating facility, wherein the pump system comprises a pump housing (1) with a pump down connecting piece (2), a pump connecting piece (3) and an intake duct (4), wherein a pump down motor (5), a pump motor (6), and a screw closure (7) to be opened, on which an essentially cylindrical filter insert (8) which can be removed from the washing machine is attached and which has at least one opening (9) for the passage of aqueous liquid along its periphery, are arranged on the pump housing (1), so that the pump housing (1) comprises an essentially cylindrical suction chamber (10), a pump down pressure chamber (11) and a pump pressure chamber (12), and wherein the pump down motor (5) is arranged so as to convey an aqueous liquid from the essentially cylindrical suction chamber (10) via the pump down pressure chamber (11) and the pump down connecting piece (3) into a pump down line and the pump motor (6) is arranged in order to convey the aqueous liquid out of the essentially cylindrical suction chamber (10) via the pump pressure chamber (12) and the pump connecting piece (3) into a pump line, wherein the essentially cylindrical filter insert (8) has the removable closure (7) at a first end (15), a pump down seal (17) for sealing the pump down pressure chamber (11) against the essentially cylindrical suction chamber (10) at a second end (16) and a pump opening (9) to the pump pressure chamber (12) at its periphery, wherein the periphery has a shield (18) enclosing the pump opening (9), said shield being surrounded by a labyrinth seal (2) and sealing the pump pressure chamber (12) against the suction chamber (10), wherein the shield (18) has a connection area (19), by way of which the shield (18) is connected directly or indirectly to the first end (15) of the cylindrical filter insert (8), comprising the steps (a) controlling the pump down motor (5) and / or the pump motor (6) by means of the control or regulating facility in such a way that one of these motors (5, 6) is switched on, i.e. activated or controlled, and the other is switched off; (b) drawing an aqueous liquid into the suction chamber (10) by means of the controlled pump down motor (5) or the controlled pump motor (6); (c1) conveying the aqueous liquid out of the essentially cylindrical suction chamber (10) via the pump pressure chamber (12) and the pump connecting piece (3) into the pump line; or (c2) conveying the aqueous liquid out of the essentially cylindrical suction chamber (10) via the pump down pressure chamber (11) and the pump down connecting piece (2) into the pump down line.

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