EP2504482B1 - Laundry appliance with a steam generator and a method of operating a laundry appliance - Google Patents

Description

The invention relates to a laundry treatment appliance, comprising a rotatable laundry drum, which is mounted on a bearing plate, a steam generator with a heating unit for generating a vapor from a liquid and at least one with the heating unit fluidly connected steam outlet opening which opens into the laundry drum, wherein the steam generator and the Dampfauslassöffnung are arranged on the bearing plate. The invention also relates to methods for operating such a laundry treatment device.

A laundry treatment device of the type mentioned is apparent from the document EP 2 053 155 A1 , The laundry treatment appliance has a tub in which a laundry drum is rotatably mounted and on which a heating device and a spraying device for spraying water onto the heating device for the purpose of generating steam to be introduced into the laundry drum are arranged.

There are other laundry treatment devices of the type mentioned are known, which treat a laundry by means of steam or by means of cold atomized water. The known devices using the steam use a steam generator which is arranged on a floor assembly in a region of a heat exchanger (for example on its cover). The generated steam is fed through a hose and possibly a nozzle in the laundry drum.

The font WO 1996/032607 A1 relates to a steam generator, in particular for the domestic sector, and also relates to a method and a device for automatically performing a refilling of a reservoir of the steam generator. In particular, it is disclosed that a temperature within a cell that is in communication with the reservoir is measured by means of a temperature sensor. When a level within the cell reaches a minimum level, the temperature detector is surrounded by vapor, the temperature of which is higher than a temperature of the liquid, and allows liquid tracking through the liquid Cell in the reservoir. When the liquid is channeled into the cell, it cools the temperature sensor and the fluid supply is stopped again.

The font EP 1 026 306 B1 relates to an automatically refillable steam generator for use with a steam cleaning equipment, a steam iron, steam generating ironing boards with refill function, coffee machines, etc. The steam generator has at least one heating element disposed on the outside of the steam generator and is equipped with a thermostat, the steam generator having one side of a steam generator Water reservoir is connected via a pump and a hose.

It is the object of the present invention to provide a simple and compact way of introducing steam into a laundry drum of a laundry treating appliance, wherein the steam has a small number and / or size of water droplets.

This object is achieved by a laundry treatment device or a method according to the features of the corresponding independent claim. Preferred embodiments are particularly apparent from the dependent claims and the following description. Preferred embodiments of the laundry treating appliance correspond to preferred embodiments of each process and vice versa, and preferred embodiments of each inventive process correspond to preferred embodiments of each correspondingly different process; this applies to the extent of the technically possible and even if this is not explicitly indicated in individual cases.

The object is achieved by means of a laundry treatment device, in particular laundry drying device, which has a rotatable laundry drum, which is mounted on a bearing plate, as well as a steam generator with a heating unit for generating a vapor from a liquid and at least one (eg via at least one steam channel) the heating unit fluidly connected steam outlet opening which opens into the laundry drum. The steam generator and the steam outlet opening are arranged or attached to the bearing plate. moreover the steam generator to a liquid reservoir, which is arranged directly on the bearing plate.

By means of the steam generator, a liquid, e.g. Water with or without additives (for example, a fragrance), heated to its boiling point and passed the boiling steam on the steam outlet in the laundry drum. The steam can here be understood to mean pure steam or additionally steam enriched with water droplets ('mist').

In this device, the steam generator can be positioned close to, in particular immediately adjacent, the at least one steam outlet opening, whereby short steam channel lengths between the steam generator and the at least one steam outlet opening can be realized. In turn, no or very little condensate forms on the inner wall or the inner walls of the steam channel. Thus, even without a special Tropfenabscheidereinrichtung be prevented that drops are accelerated by the vapor pressure in the drum and produce there stains on the laundry or the textiles.

The at least one vapor channel, which carries the vapor from the heating unit to the at least one vapor outlet opening, may be at least partially thermally insulated to further suppress condensation and thus formation of water droplets. The steam channel is particularly short, may even be negligible short, if the steam outlet is coupled directly to the steam generator.

According to the invention, the steam generator has a water reservoir. In other words, a water reservoir can be integrated in the steam generator. Consequently, the water reservoir is attached to the bearing plate, which allows a particularly compact arrangement with a small fluid channel length. Preferably, the steam generator is mounted directly on the end shield, e.g. latched, screwed and / or glued.

It is a preferred embodiment that the heating unit comprises a water heater or is designed as such. The water heater can be particularly elongated for a particularly suitable for attachment to the bearing plate manner, in particular tubular, be configured. It is a particularly compact and easy-to-assemble configuration that the steam generator is not or not substantially laterally (in height and width extension) beyond the contour of the bearing plate.

It is a particularly preferred embodiment that the water heater is aligned at least obliquely upright. In particular, an outlet end may be higher than an inlet end. This helps to quickly evaporate the liquid and reduces the formation of droplets. In particular, the instantaneous water heater may be upright at least at an angle of 45 ° or more to a horizontal. In general, the water heater can be aligned as perpendicular as possible or at the greatest possible angle to the horizontal operating position. It is a particularly advantageous embodiment that the water heater is installed substantially vertically.

It is still a particularly preferred embodiment that a boiling mirror (ie, a surface of the liquid) is located in an initial third of the water heater, ie, subsequent to the inlet end. Even so can one rapid evaporation of the liquid and a reduction in the formation of drops are supported.

It is an alternative preferred embodiment that the heating unit comprises a boiler or is designed as such. The boiler has an integrated liquid reservoir. In contrast, the water heater works without an integrated liquid reservoir. It is a further preferred embodiment that the liquid reservoir is a heater component, e.g. a heating plate as or in the bottom of the liquid reservoir. The liquid is then evaporated in the liquid reservoir.

It is a further preferred embodiment that at least one temperature sensor is arranged at an inlet end of the heating unit, in particular the continuous flow heater. As a result, a simple and reliable dry protection can be realized. The temperature sensor can be arranged, for example, on a surface of a heating tube of the flow heater, whereby a rapid response of the temperature sensor can be achieved on a dry cycle.

• Überwachen einer Temperatur an der Heizeinheit, insbesondere an einem Einlassende der Heizeinheit, auf ein Überschreiten eines vorbestimmten Temperaturwerts und/oder eines vorbestimmten Temperaturgradienten und
• Herunterfahren und/oder Abschalten der Heizeinheit als Reaktion auf das Überschreiten.

The dry protection can be realized, for example, by a method which also solves the above-mentioned object, with the following steps:

• Monitoring a temperature at the heating unit, in particular at an inlet end of the heating unit, at a predetermined temperature value and / or a predetermined temperature gradient being exceeded, and
• Shut down and / or shut down the heating unit in response to the overshoot.

It is also possible to monitor for an undershooting of a further, lower temperature gradient, in particular a negative temperature gradient.

If the heating unit is supplied with sufficient liquid, by a heat entrainment of the liquid, a temperature is kept low, in particular at the inlet end of the heating unit. If the volume flow of the liquid drops or even stops (dry off), the temperature applied to the heating unit increases. Falling below a critical volume flow can be achieved by exceeding the predetermined temperature value be imaged. This applies analogously to a temperature gradient, whereby a reduction in the volume flow of the liquid and a dry-running can be detected by a corresponding temperature gradient.

It is also a preferred embodiment that at least one temperature sensor is mounted at an outlet end of the heating unit (a portion of the heating unit where steam has already been generated), in particular a continuous flow heater. The measured values sensed by this at least one temperature sensor can be used for a temperature control, wherein an amount of the delivered liquid (volume flow) represents a possible control variable for the temperature control.

Also, exceeding a temperature threshold and / or a temperature gradient at the outlet end may be used to detect overheating of the heating unit, e.g. as described above for the inlet end, possibly followed by a shutdown and / or shutdown of the heating unit in response to the exceeding.

It is still a preferred embodiment that the heating unit is provided with a resettable thermal fuse, e.g. a bimetal element, to prevent non-critical temperature excesses, which do not cause permanent damage to the heater.

It is yet another preferred embodiment that the heating unit be provided with a non-resettable thermal fuse, e.g. a fuse, is equipped to prevent even severe temperature excesses, which could cause permanent damage to the heater.

It is a specific preferred embodiment that the resettable thermal fuse and the non-resettable thermal fuse are attached to the heater as a structural unit. In particular, the structural unit may be mounted on a suitable mounting device in an upper part of the heating unit. In particular, the thermal fuses may be electrically connected in series in a circuit of the heating unit.

In particular, an evaporator may have all of the temperature sensors and / or temperature protections mentioned in order to ensure high intrinsic safety of the steam generator, especially against overheating in the event of a lack of liquid (for example in the case of a defective pump or a defective or clogged liquid feed channel).

It is a further development that the heating unit has at least one temperature sensor at an outlet end of the heating unit, a resettable thermal fuse, a non-resettable thermal fuse, and at least one dry-run protection (e.g., temperature sensor, level gauge) at an inlet end of the heating unit.

It is also a preferred embodiment that a pump is arranged on a housing of the water reservoir. This allows a particularly compact device. The pump may e.g. be arranged in the liquid reservoir to allow a particularly compact design.

It is also a preferred embodiment that a fluid channel from the pump to the heating unit is at least partially formed in the housing of the water reservoir. As a result, can be dispensed with tubing for fluid management between the pump and the heating unit, which increases reliability and saves costs. Another part of the liquid channel may e.g. be formed by a housing cover of the steam generator. It is a development that the water reservoir directly adjacent to the heating unit and is connected to this without intermediate elements.

It is likewise a preferred embodiment that the steam generator has at least one molded fluid channel. The fluid channel may include a fluid channel, a vapor channel or a combined liquid / vapor channel. A molded fluid channel reduces the cost of the steam generator due to a lower material and assembly costs and reduces the risk of failure by eg loosening hoses. It is a particular embodiment that the steam generator has only molded-fluid channels and therefore has no hoses or other intermediate pieces, which can be solved in an operation of the laundry treatment device.

A filling of the liquid reservoir can be done in particular with water as the liquid, optionally with at least one additive. The water is preferably descaled or has only a small amount of lime. The water can be manually filled by the user, e.g. through a suitable filling opening in a region of a condensate casing.

Alternatively or additionally, the condensate water produced, for example, during a drying process can be conducted into the liquid reservoir, e.g. by driving a three-way valve from a condensate pump instead of being directed into the condensate tank. In this case, in order to prevent clogging and a failure of the steam generator, it is advantageous if a filter element is present in front of the liquid reservoir, e.g. integrated at its entrance to filter out fine lint and other particles from the condensate.

It is a further preferred embodiment that the steam generator has a pressure relief valve for discharging pressurized liquid into the liquid reservoir. Thereby, a malfunction or even damage of the steam generator with a clogging on the steam side can be avoided. It is particularly preferred if the pressure relief valve triggers (in particular opens), if a nominal vapor pressure is exceeded by about 0.5 bar to 1 bar. The pressure relief valve may be, for example, a spring-loaded ball valve. The pressure relief valve may in particular be arranged in a fluid channel between and / or including a pressure outlet of a feed pump and an inlet end of a flow heater. Alternatively, the relief valve may be disposed on a vapor side, particularly between and / or including an outlet end of the flow heater or boiler and a vapor outlet nozzle.

It is still a preferred embodiment that the steam generator is a vapor having a vapor pressure of about 0.25 bar to 2 bar, in particular from about 0.3 bar to 1.5 bar, in particular from 0.5 bar to 1 bar. This pressure range can, inter alia, by a suitable vote of an energy input (eg represented by a heating power of the heating unit), a dosage of the amount of liquid in the water heater (eg by means of a setting a timing or control of a feed pump for the liquid to be evaporated) and / or Opening width of the at least one steam outlet opening can be achieved. This embodiment leads to a reduction of the formation of drops. This suitably high vapor pressure also affects the quality of the steam; as the steam becomes 'drier'. In addition, vapor components may more strongly swirl with the air in the drum, thereby making the temperature of the vapor mixture less critical with respect to treatment of any type of fabric, as well as in the event that the user opens the door and grips the drum during the program.

The at least one steam outlet opening can be designed as at least one outlet nozzle. The at least one steam outlet opening may advantageously be directed at an angle into the laundry drum, so that the steam jet exiting through the at least one steam outlet opening is directed into the center of the drum, in particular into a region slightly below the drum center line. As a result, the intended typical load cases (up to about 2 kg of textiles) are hit particularly effectively by the steam jet, which allows a good steaming of the laundry in short program times.

The laundry treating appliance may in particular be a laundry drying appliance, e.g. a tumble dryer or a washer dryer.

The described laundry treatment device allows a good refresh function with comparatively short treatment times. The steam generator can be designed as a compact, preassemblable and testable unit. The steam generator can in particular be equipped and preassembled as a unit with all the necessary functional elements and safety elements. The steam generator can thus be completely pre-assembled by a system supplier and checked for all system functions, including safety functions. The steam generator provides a high level of intrinsic safety. The steam generator can be integrated according to a development in particular directly at the injection point in existing clearances of the bearing plate of the drum.

The above-mentioned object is also achieved by a method for operating a laundry treatment appliance, in particular a laundry treatment appliance as described above, wherein multiple steam is passed to a laundry located in a rotary laundry drum and at the same time or (for better uniform distribution of moisture in the laundry) alternately the Laundry is circulated. Such a method can be used to make the fibers of the laundry soft and supple ("wrinkle out"). For this purpose, the interior of the laundry drum is preferably not or only slightly heated to maintain residual moisture in the laundry, and the laundry is preferably alternately steamed and moderately agitated.

The object is also achieved by a method as described above, wherein the interior of the drum is additionally heated. This method can be used in particular for refreshing the laundry ("odor removal") if the liquid applied to the textiles is caused to evaporate by heating the interior of the drum. This steam extraction removes odor molecules from the laundry.

It is a preferred development that first the process for refreshing the laundry is performed and following the process for crumpling the laundry is performed. But it is also the reverse order possible.

Fig.1

zeigt in Ansicht von schräg vorne ein Lagerschild eines Wäschetrockners mit einem Dampferzeuger gemäß einem ersten Ausführungsbeispiel;

Fig.2

zeigt als Schnittdarstellung in Ansicht von schräg vorne das Lagerschild mit dem Dampferzeuger gemäß dem ersten Ausführungsbeispiel

Fig.3

zeigt in Ansicht von schräg unten einen Dampferzeuger gemäß einem zweiten Ausführungsbeispiel;

Fig.4

zeigt in Ansicht von schräg hinten den Dampferzeuger gemäß dem zweiten Ausführungsbeispiel;

Fig.5

zeigt in Ansicht von vorne ein Lagerschild eines Wäschetrockners mit einem Dampferzeuger gemäß einem dritten Ausführungsbeispiel;

Fig.6

zeigt eine Funktionsskizze eines möglichen Dampferzeugers des Wäschetrockners gemäß dem ersten Ausführungsbeispiel;

Fig.7

zeigt einen ersten Teil eines möglichen Ablaufdiagramms eines Wäscheauffrischungsverfahrens zum Betreiben des Wäschetrockners mit dem Dampferzeuger aus Fig.3;

Fig.8

zeigt einen zweiten Teil eines möglichen Ablaufdiagramms des Wäscheauffrischungsverfahrens aus Fig.3;

Fig.9

zeigt eine Funktionsskizze eines weiteren möglichen Dampferzeugers des Wäschetrockners gemäß dem ersten Ausführungsbeispiel; und

Fig.10

zeigt einen ersten Teil eines möglichen Ablaufdiagramms eines Wäscheauffrischungsverfahrens zum Betreiben des Wäschetrockners mit dem Dampferzeuger aus Fig.6.

In the following figures, the invention will be described schematically with reference to an embodiment schematically. In this case, the same or equivalent elements may be provided with the same reference numerals for clarity.

Fig.1

shows in oblique view from the front a bearing plate of a clothes dryer with a steam generator according to a first embodiment;

Fig.2

shows a sectional view in oblique view from the front bearing plate with the steam generator according to the first embodiment

Figure 3

shows in view obliquely from below a steam generator according to a second embodiment;

Figure 4

shows in oblique view from the rear of the steam generator according to the second embodiment;

Figure 5

shows in front view of a bearing plate of a clothes dryer with a steam generator according to a third embodiment;

Figure 6

shows a functional diagram of a possible steam generator of the clothes dryer according to the first embodiment;

Figure 7

shows a first part of a possible flowchart of a laundry refreshing process for operating the tumble dryer with the steam generator Figure 3 ;

Figure 8

Figure 2 shows a second part of a possible flowchart of the laundry refreshing process Figure 3 ;

Figure 9

shows a functional diagram of another possible steam generator of the clothes dryer according to the first embodiment; and

Figure 10

shows a first part of a possible flowchart of a laundry refreshing process for operating the tumble dryer with the steam generator Figure 6 ,

Fig.1 shows in a view from the front and Fig.2 shows a sectional view in oblique view from the front a bearing plate 1 of a clothes dryer 2 with a steam generator 3 according to a first embodiment. The steam generator 3 is attached directly to the bearing plate 1, for example, locked, screwed and / or glued. The steam generator 3 has a water heater 4. In this case, the steam generator 3 is dimensioned so that it does not extend (in front view) laterally or not substantially beyond the bearing plate 1, which simplifies an adaptation of the embodiment of the laundry dryer 2 to the steam generator 3. For such a simple adaptation of the steam generator 3 to the bearing plate 1, the water heater 4 with its heating tube 5 is not vertical, but installed at an angle. In this case, an inlet end 6, at which a liquid to be heated, here: water, is introduced, is lower than an outlet end 7, at which a vapor produced by heating the liquid introduced exits.

The liquid to be supplied to the flow heater 4 at the inlet end 6 originates from a liquid reservoir 9 which forms part of the steam generator 3. The liquid reservoir 9 is connected directly to the bearing plate 1, and the water heater 4 is connected directly to the liquid reservoir 9. As a result, a complex and error-prone laying of long tubes is avoided. The flow heater 4 is More specifically, in an elongated recess 10 in the liquid reservoir 9 and its housing used, so that the water heater 4 is not or only slightly forward projecting from the liquid reservoir 9, resulting in a compact design.

The liquid reservoir 9 is connected via a filling funnel 11 with a higher water reservoir 26. The filling funnel 11 is attached directly to a filler neck 27 of the liquid reservoir 9. The water reservoir 26 may be manually filled by a user (e.g., with descaled water and / or with additives), charged from a condensate water tank (which is, for example, on a floor assembly), and / or the condensate water tank of the clothes dryer 2. Alternatively, the liquid reservoir 9 can be filled manually by a user via a removable filling funnel.

The liquid contained in the liquid reservoir 9 is pumped to the inlet end 6 by means of a back-mounted feed pump and fills the heating tube 5 up to an at least roughly predetermined water level. At the level of the water level, there is consequently the liquid surface of the standing liquid which is also called boiling mirror.

The heating tube 5 is adjacent to a heating element 8 powered by current, for heating the liquid and subsequent steam generation in it. The steam may be water droplets (and thus generally a mixture of pure steam and water), with a small amount of water droplets or even their absence being preferred. For a drip-free vapor as possible, the boiling level is set in an initial third of the instantaneous water heater (ie close to the inlet end 6). For the same purpose, the steam is produced at a vapor pressure of 0.25 bar to 2 bar, in particular from 0.3 bar to 1.5 bar, in particular from 0.5 bar to 1 bar. The steam rises to the outlet end 7.

The outlet end 7 of the flow heater 4 leads via a steam channel in the form of a short connecting hose 31 to a steam outlet nozzle 12, which is also attached to the bearing plate 1 as a separate component. The connecting tube between the outlet end 7 and the steam outlet nozzle 12 can be kept short due to their spatial proximity and is also thermally insulated, whereby a drop formation is suppressed on a wall of the steam channel, so that no or only a few such droplets are entrained with the steam to the steam outlet and further into the laundry drum W.

The steam outlet nozzle 12 opens into a rotatable laundry drum W of the tumble dryer 2. The steam outlet nozzle 12 is directed obliquely downwards so that the steam jet emitted by it is directed to slightly below the center of the laundry drum W to provide typical laundry loads, e.g. of about 2 kg to be able to steam effectively. The laundry drum W can be loaded by a loading opening B of the endshield 1.

In order to adequately steam a fuller laundry drum W, the Dampfauslassdüse is attached to or near the upper vertex d of the bearing plate 1, but at least on an upper half of the bearing plate 1. Consequently, a positioning of the steam generator 3 at an upper half of the bearing plate. 1 prefers.

The steam generator 3 further comprises an NTC temperature sensor (not shown), which is arranged at the outlet end 7 of the water heater 4. Among other things, the NTC temperature sensor may be used to measure a steam temperature of the generated or exiting steam to control the steam temperature in a predetermined range or to a predetermined value. The designed for this control device is not shown. If a steam temperature of the NTC temperature sensor exceeds a predetermined threshold value, which may indicate an excessively high operating pressure, the steam generator 3 can be switched off.

The steam generator 3 also has accommodated in a common housing 28 a reversible temperature switch in the form of a bimetallic switch and an irreversible temperature switch in the form of a fuse, which are arranged on the heating element 8 in the circuit. The reversible temperature switch interrupts the power supply to the heating element 8, if an associated temperature threshold is reached or exceeded. The irreversible temperature switch interrupts the power supply to the heating element 8 permanently, if an associated, higher temperature threshold is reached or exceeded. By means of the reversible temperature switch a low, non-critical overheating of the heating element 8 is avoided, for example, in an initial stage of dry-running. By means of the irreversible temperature switch a strong, leading to lasting damage overheating avoided, for example, in advanced dry running. The irreversible temperature switch thus also protects against a failure of the irreversible temperature switch.

Dry running is also avoided by a level sensor or level sensor located in or on the liquid reservoir 9 (not shown).

The various sensors and switches thus enable a particularly safe operation of the steam generator 3, in particular by its multi-stage and / or redundant design with regard to dry running. The operation of the sensors and switches will be more detailed in Fig.6 to Fig.10 described.

To avoid a supercritical vapor pressure, a pressure relief valve 20 is provided in the liquid channel between the feed pump and the inlet end 6, which opens the liquid channel with respect to the liquid reservoir 9 from a predetermined pressure threshold value. For this purpose, the pressure relief valve 20, which is formed here in one piece with the inlet end 6, is connected to the liquid reservoir 9 via a short return hose 29. The liquid from the feed pump is brought from the back of the liquid reservoir 9 by means of a hose 30. Clogs the steam side of the steam generator 3, e.g. by clogging the outlet end 7 or the steam outlet nozzle 12, the vapor pressure and consequently the pressure of the liquid at the inlet end 6 increases. Preferably, the pressure relief valve 20 opens at a pressure which is 0.5 bar to 1 bar above the typical or nominal steam operating pressure lies. As a result, liquid is passed back into the reservoir 9 through the return hose 29 while reducing the pressure. The pressure relief valve 20 may e.g. having a spring-loaded ball as the closure element. By selecting the spring force, a switching point can be set.

The NTC temperature sensor at the outlet end 7 may be connected to detect a blockage so that a multiple, especially in approximately periodic, recurring temperature increase is detected. Because the increase in vapor pressure associated with the blockage can also cause the vapor temperature to increase. wherein the steam temperature decreases after the opening of the pressure relief valve 20 by the pressure reduction again. With a clogging of the steam side, the rise and fall of the steam temperature is repeated regularly and can be detected by the occurrence of several temperature peaks, for example within a predetermined time interval. As a result, the steam generating unit 3 can be switched off, possibly with the output of a corresponding error message such as "nozzle clogged".

Figure 3 shows in oblique view from obliquely behind and below in oblique view from behind a steam generator 33 according to a second embodiment. In contrast to the steam generator 3, the steam outlet nozzle 12 is now attached to the steam generator 33 and forms part of it. The steam generator 33 can thus be pre-assembled and tested with the steam outlet nozzle 12, which enables a particularly inexpensive and effective preliminary test.

Figure 4 shows the steam generator 33 of its the bearing plate 1 facing back. As with the steam generator 3, the feed pump 19 is attached to the liquid reservoir 9, in the housing 9 of the liquid reservoir protruding receptacles 24. The suction side of the feed pump 19 is connected via a short suction hose 34 with an intake port 35 of the liquid reservoir 9 and introduced about it. The pressure side of the feed pump 19 is connected via the hose 30 to the pressure relief valve 20 and the inlet end 6.

Figure 5 shows in front view of a bearing plate 1 of a clothes dryer W with a steam generator 13 according to a third embodiment similar to Fig.1 , In contrast to the first embodiment, the heating unit is now designed as a boiler 14, which has an integrated liquid reservoir 15 with a serving as a bottom plate of the liquid reservoir 15 heating plate 16. The liquid reservoir 15 is connected to the filling funnel 11 not via a hose, but a rigid liquid feed channel 17, which may be formed integrally with the liquid reservoir 15 or with the filling funnel 11. An upper outlet end 18 of the boiler 14, from which the steam exits, is connected directly to the steam outlet nozzle 12.

Figure 6 shows a functional diagram of a possible steam generator 3 or 33 of the clothes dryer 2 according to the first and the second embodiment. The in the Liquid reservoir 9 located liquid F, in particular decalcified water is pumped via an evaporator pump or pump 19 to the water heater 4. The feed pump 19 can be operated, for example, in a pulse mode. To avoid damage to the water heater 4 and to avoid malfunction of the feed pump 19, a pressure relief valve 20 is connected in fluidic parallel. The funded by the pump 19 fluid F is conveyed into the heating tube 5 of the water heater 4 and brought there by means of the heating element 8 of the water heater 4 to boiling. In order to suppress or completely avoid the formation of droplets in the vapor D generated by the flow heater 4, a boiling mirror is provided in a lower third of the heating tube 5, ie, fluidly behind the inlet end 6. The vapor D generated in the heating tube 5 emerges from the outlet end 7 as shown by the arrow and is forwarded to the steam inlet nozzle.

The steam generator 3, 33 is protected by four protection units, namely an NTC temperature sensor T1, which is arranged on the steam side of the outlet end 7 of the water heater 4, a reversible temperature switch T2 in the form of a bimetallic switch, which is arranged on the heating element 8, a irreversible temperature switch T3 in the form of a fuse, which is also associated with the heating element 8, and a level sensor or level sensor N in or at the liquid reservoir. 9

The NTC temperature sensor T1 serves to measure a steam temperature of the generated or exiting steam D. The measured values of the NTC temperature sensor T1 may be input to a controller (not shown) of the clothes dryer 2 to maintain the steam temperature in a predetermined range or at a predetermined value. For this purpose, for example, the feed pump 19 can be used to promote more or less liquid F. If more liquid F is conveyed, the steam temperature drops at a constant heat output, conversely the steam temperature increases with decreasing flow rate or a sinking associated liquid volume flow. A control of the steam temperature over a delivery rate of the feed pump 19 and thus via a liquid volume flow to the water heater 4 is practical and control technology comparatively easy to perform. Alternatively or additionally, a heating power of the heating element 8 can be used to adjust the steam temperature. In particular, upon reaching and / or exceeding an associated predetermined temperature threshold, for example of 230 ° C, the heating unit for a short time (eg at least three seconds) are turned off

By means of the reversible temperature switch T2, which is integrated in a circuit of the heating element 8, a non-critical overheating of the heating element 8 is avoided, e.g. with a minor and permanent damage temperature increase. The temperature switch T2 can be designed so that, if it is installed in the circuit, the power supply to the heating element 8 directly interrupts and thus leads to a decrease in temperature.

The irreversible temperature switch T3, which may be turned on in particular in series with the reversible temperature switch T2 in the circuit of the heating element 8, serves to avoid permanent damage to the heating element 8 or other parts of the water heater 4 or even the steam generator 3, 33. Thus, if the temperature rises to a level at which the irreversible temperature switch T3 is activated, the irreversible temperature switch T3 opens (e.g., a fusing material melts) so that for further operation of the heating unit T8, the irreversible temperature switch T3 must be replaced. It is assumed that a temperature which leads to the activation of the irreversible temperature switch T3 indicates a fundamental malfunction of the flow heater 4. The temperature at which the irreversible temperature switch T3 trips, for example at 290 ° C, is higher than the temperature at which the reversible temperature switch T2 trips, e.g. 150 ° C.

As dry run protection, the level sensor N can be present, which warns of too low a liquid level in the liquid reservoir and / or triggers corresponding actions, e.g. emits a warning tone and / or temporarily stops the operation of the steam generator 3, 33. The level sensor N can be designed as a reed sensor and / or as a float.

In particular, in their combination, the four sensors or switches T1, T2, T3 and N provide a high degree of operational safety. Thus, while the NTC temperature sensor T1 is arranged to control a steam temperature of the steam D and to protect against overheating of the steam, the two temperature switches T2 and T3 secure the Heating element 8 against failure, and the level sensor N avoids dry running and thus damage to the steam generator 3, 33rd

Figure 7 FIG. 12 shows a first part of a possible flow chart of a laundry refreshing process (odor removal, etc.) for operating the clothes dryer 2 with the steam generator 3, 33 Figure 6 ,

In a first step S1, the liquid reservoir 9 is filled. For this purpose, for example, the filling funnel 11 can be manually filled by a user or automatically via a pump with condensate water from a condensate water tank. For a manual filling of the hopper 11 this can be removed. The filling funnel 11 may also constitute a condensate container.

In an optional step S2, one or more odor filters can be inserted into the process air duct of the tumble dryer 2 in order to absorb odor particles removed by steaming and heating from the laundry and to prevent their circulation in the tumble dryer 2. The odor filter may e.g. be introduced in the area of a lint filter.

In a following step S3, a program for refreshing laundry located in the laundry drum W is started. This program steams in a first section of the laundry (without heating) and then heats up the laundry, so that odor molecules are removed with the heated water molecules. It has been shown that such a sequence offers the best odor removal. During steaming, the steam generator 3 is activated.

As part of the program started in step S3, first a fill level inquiry of the liquid reservoir 9 is carried out by means of the fill level sensor N (step S4). This level query is a permanent function, that is, it is performed continuously or at regular intervals as long as the program is running.

If it is detected by the at least one fill level sensor N that a maximum fill level of the liquid reservoir 9 has been reached and / or exceeded, an alarm (optical and / or acoustic) is sent in step S5, possibly together with a display unit of the clothes dryer 2 displayed, whereby a user is informed that the level in the liquid reservoir 9 is too high. Optionally, dosage errors may be displayed online if the program has been initially selected (step S3 before step S1 in an alternative embodiment).

If a minimum fill level of the liquid reservoir 9 is reached or undershot, in a step S6 the steam generator is deactivated, e.g. and, in addition (analogously to the case of too high a level) a user is visually and / or acoustically warned, whereby a dialogue can also be displayed in a display unit (e.g., "too little water"). The user can then, e.g. fill the liquid reservoir 9 (step S1).

If a fill level of the liquid F in the liquid reservoir 9 is between the minimum fill level and the maximum fill level, the feed pump 19 is first activated in a step S7 following step S4. Since the feed pump 19 is operable in this embodiment in the pulse mode, it is clocked accordingly. As a result, the feed pump 19 conveys liquid F from the liquid reservoir 9 to the heating tube 5, which fills up accordingly.

In addition, a drive for the washing drum W for a secondary rotation is controlled (step S8), that is rotated in a direction of rotation, which corresponds to the opposite during a drying cycle direction of rotation. As a result, an air flow through the laundry drum W is reduced, which facilitates the moistening of the laundry. However, the reversal of the drum rotation direction is not mandatory and may be e.g. not used with devices with only one drum rotation direction.

After the heating tube 5 has been filled in step S7, the heating element 8 is switched on in a time-delayed manner (for example by 3 to 5 seconds) in a step S9. As a result, the liquid F in the heating tube 5 is boiled and evaporated. The thus generated steam D, here: water vapor with or without additives, exits through the outlet end 7 and continues through the steam outlet nozzle into the laundry drum W.

As a result of the evaporation, a vapor pressure builds up in the evaporator 3 and in the steam channel between the evaporator 3 and the steam outlet nozzle 12. To obtain a possible "dry" steam D, the vapor pressure is preferably within a range between 0.25 bar and 2 bar, in particular between 0.3 bar and 1.5 bar, in particular between 0.5 bar and 1.0 bar.

Figure 8 shows a second part of a possible flowchart of a method for operating the clothes dryer 2 with the steam generator 3 from Figure 6 , which follows the flowchart Figure 7 followed. After in step S9 in Figure 7 When the heating element 8 has been switched on or activated, the NTC temperature sensor T1 measures the steam temperature of the generated steam D in a step S10. This takes place continuously, for example at regular intervals. Via the values determined by the temperature sensor T1, the delivery rate of the delivery pump 19 is regulated to adjust the steam temperature, for example by storing characteristic curves in a look-up table of a central control unit.

When the steam temperature reaches or exceeds a predetermined steam temperature threshold, e.g. 230 ° C, the heating element 8 in step S11 for a predetermined period of time, e.g. at least 3 seconds, switched off. It is assumed that at a constant entry of a heating power through the heating element 8, the delivery rate or the maximum liquid volume flow of the feed pump 19 is not sufficient to lower the steam temperature sufficiently.

At the same time, the reversible temperature switch T2, which is designed as a bimetal switch, and the irreversible temperature switch T3 "measure" or react in a step S12 to a temperature T _A0 applied to the heating element 8. If the temperature T _{A0 of} the heating element 8 reaches or exceeds a first safety threshold, eg 150 ° C., the temperature switch T2 opens and thereby interrupts the power supply to the heating element 8, whereupon it cools down (step S13). Since the temperature switch T2 is reversible, it will close after a drop in the temperature of the heating element 8 to the first safety threshold or in the presence of a hysteresis to an underlying temperature value, so that the heating element 8 is operated again. Exceeds the temperature T _{A0 of} the heating element 8 a second safety threshold, which is higher than the first safety threshold, eg 230 ° C, the irreversible temperature switch T3 is activated and interrupts the circuit of the heating element 8 until its replacement, for example by a customer service, which can check the water heater 4. This will ensure that that Heating element 8, the water heater 4 or the steam generator 3 are not irreparably damaged. For example, the irreversible temperature switch T3 protects against a failure of the reversible temperature switch T2.

With a failure-free reaching of one end of a period of the evaporator function, e.g. after five minutes, the heating element 8 is first turned off in a step S15. Thereafter, in a step S16, the feed pump 19 is turned off. In order to avoid overheating of the flow heater 4, the feed pump 19 is switched off in a delayed manner compared with the heating element 8, e.g. with a time delay of two to five seconds. In a following step S17, the laundry drum W is stopped, whereby the evaporation section is finished.

The drying section starts in a following step S18 in which the laundry drum is again started in the main rotating direction and in a step S19 a drum heater is activated to heat an air in the laundry drum, e.g. to a power of about 2000 watts, which is e.g. a heating level 2 may correspond. This drying section may be performed for a predetermined period of time, e.g. for six minutes.

After or at an end of the drying section from step S19, the program is ended in a last step S20. In the following, the laundry can be taken out of the laundry drum W and e.g. be hung up. Alternatively, the evaporation section of steps S4 to S17 and the drying section of steps S18 and S19 may be repeated one or more times.

A sequence for the crumbling of the laundry, which corresponds approximately, in particular precisely, to the sputtering section with the steps S4 to S17, can follow the described refreshment procedure. The unfreezing process can also be activated separately.

Figure 9 shows a functional diagram of another possible steam generator 21 of the clothes dryer 2 according to the first or the second embodiment using a water heater 22nd

The steam generator 21 is similar to that in FIG Figure 6 constructed, except that now instead of the level sensor N, a second NTC temperature sensor T4 is mounted in the region of an inlet end 6 of the water heater 22, preferably on the heating tube 5 in a region in which the heating tube 5 in operation still filled with liquid F. is. The second NTC temperature sensor T4 is operated permanently. Due to the constant tracking of liquid F in the operation of the flow heater 22, the heating tube 5 is permanently cooled at its inlet end 6. If the liquid flow F remains or drops to a low level (dry running), the cooling of the heating tube 5 in the region of the second NTC temperature sensor T4 decreases, so that the temperature rises there. Consequently, dry-running of the flow heater 22 due to a lack of liquid in the liquid reservoir 9 or a blockage can be detected by exceeding a temperature threshold of the second temperature sensor T4 or by a (too) rapid increase in temperature at the location of the second temperature sensor T4. As a result, it is possible to dispense with a mechanically more complicated fill level sensor N. Alternatively or additionally, exceeding a temperature threshold value by the second temperature sensor T4 can be used to detect dry-running.

Figure 10 shows a first part of a possible flowchart of a method for operating the clothes dryer 2 with the steam generator 21 from Figure 9 , Unlike the flowchart Figure 7 Drying is now detected by the second NTC temperature sensor T4 measuring temperature readings T at regular times in a step S21 after switching on the heating element 8 in step S9, which are converted in the central control unit into corresponding temperature gradients ΔT over successive time intervals. Steps S4 to S6 off Figure 7 however, omitted.

If it is determined in step S21 that the measured temperature gradient .DELTA.T reaches and / or exceeds a predetermined maximum temperature gradient, the heating element 8 is deactivated and all program functions are stopped (step S22). In addition, a corresponding alarm is issued and, if necessary, a dialog is displayed, eg in the sense of "lack of water". The user can then refill the liquid reservoir 9. Should it despite refilling the liquid reservoir 9 continue to If this error message comes in, for example, an instruction manual may indicate that the customer service has been notified.

If it is determined in step S21 that the measured temperature gradient .DELTA.T reaches and / or falls below a predetermined minimum temperature gradient, the heating element 8 is likewise deactivated, and all program functions are also stopped in this case (optional step S23). In addition, a corresponding alarm is output and, if necessary, a dialog is displayed, e.g. in the sense of "thermal fuse defective". Thus, e.g. a lifetime-related flattening of a voltage / temperature characteristic can be detected. The user should then contact customer service.

For example, in the first part of the flowchart shown in FIG Figure 8 shown part of the flowchart of the first variant of the steam generator 3 connect.

It may be an embodiment that via the first NTC temperature sensor T1 also a query of the temperature gradient is performed, which queries whether a temperature gradient is less than one, where similar to step S23, the heating unit is turned off, all program functions are stopped and an alarm / Dialog "Thermal fuse defective" will be output.

Of course, the present invention is not limited to the embodiments shown.

Thus, the reversible temperature switch T2 instead of a bimetal switch, for example, also use a corresponding interconnected NTC sensor.

LIST OF REFERENCE NUMBERS

1

end shield

2

clothes dryer

3

steam generator

4

Heater

5

heating pipe

6

Inlet end of the water heater

7

Outlet end of the water heater

8th

Heating element of the water heater

9

liquid reservoir

10

recess

11

loading hoppers

12

steam outlet nozzle

13

steam generator

14

boiler

15

liquid reservoir

16

heating plate

17

Liquid supply channel

18

Outlet end of the boiler

19

feed pump

20

Pressure relief valve

21

steam generator

22

Heater

23

Housing of the liquid reservoir

24

admission

26

water reservoir

27

filler pipe

28

casing

29

Return hose

30

tube

31

connecting hose

33

steam generator

34

Suction

35

intake

W

washing drum

B

loading opening

S1-S23

process steps

T1, T4

temperature sensor

T2, T3

temperature switch

Claims (13)

1. Laundry treatment appliance, having

   - a rotatable drum (W) mounted on an end shield (1),

   - a steam generator (3; 13; 21; 33) having a heating unit (4; 14; 22) for producing steam (D) from a liquid (F) and

   - at least one steam outlet port (12) fluidically connected to the heating unit (4; 14; 22) and opening into the drum (W), wherein the steam generator (3; 21; 33) and the steam outlet port (12) are arranged on the end shield (1),

   characterised in that the steam generator (3; 13; 21) comprises a liquid tank (9; 15; 26) which is arranged directly on the end shield (1).
2. Laundry treatment appliance according to claim 1, wherein the heating unit (4; 22) has a flow-through heater which is oriented at least obliquely upright at an angle of at least 45° from the horizontal.
3. Laundry treatment appliance according to either claim 1 or claim 2, wherein the heating unit (4; 22) has a flow-through heater whose boiling meniscus is in an initially present third of the flow-through heater (4; 22).
4. Laundry treatment appliance according to one of the preceding claims, wherein the heating unit (4; 22) has

   - at least one temperature sensor (T1) at an outlet end (7) of the heating unit (4; 22),

   - a resettable thermal cutout (T2),

   - a non-resettable thermal cutout (T3) and

   - at least one run-dry protection element (T4; N) at an inlet end (6) of the heating unit (4; 22).
5. Laundry treatment appliance according to one of the preceding claims, wherein a pump (19) is disposed on a housing (23) of the liquid tank (9).
6. Laundry treatment appliance according to claim 5, wherein the pump (19) is disposed in the liquid tank (9).
7. Laundry treatment appliance according to one of the preceding claims, wherein the steam generator (3; 13; 21; 33) has an overpressure valve (20) for diverting pressurised liquid (F) into the liquid tank (9), wherein the overpressure valve (20) opens if a nominal steam pressure is exceeded by approximately 0.5 to 1 bar.
8. Laundry treatment appliance according to one of the preceding claims, wherein the steam generator (3; 13; 21) produces steam with a nominal steam pressure of approximately 0.25 to 2 bar, in particular of approximately 0.3 to 1.5 bar.
9. Laundry treatment appliance according to one of the preceding claims, wherein the steam generator (3; 13; 21; 33) protrudes at least insignificantly laterally beyond the outline of the end shield (1).
10. Method for operating a laundry treatment appliance (2) according to claim 4, wherein the method comprises at least the following steps:

    - monitoring of a steam temperature by the temperature sensor (T1) disposed at the outlet end (7) to detect overshooting of a predetermined steam temperature threshold value,

    - monitoring of a temperature of a heating element of the steam generator (3; 21; 33) by the resettable thermal cutout to detect overshooting of a first predetermined safety threshold value,

    - monitoring of a temperature of a heating element of the steam generator (3; 21; 33) by the non-resettable thermal cutout to detect overshooting of a second predetermined safety threshold value and

    - shutdown and/or disconnection of the heating unit (4; 14; 22) in response to the overshoot,

    - wherein the second safety threshold is higher than the first safety threshold value.
11. Method according to claim 10, wherein the heating unit (4; 14; 22) is shut down and/or disconnected for a predetermined time in response to the overshooting of the steam temperature threshold value.
12. Method for operating a laundry treatment appliance (2) according to one of claims 1 to 9, therein steam (D) is repeatedly conveyed to laundry in a rotatable drum (W) and the laundry is alternatingly rotated.
13. Method according to claim 12, wherein the interior of the drum (W) is heated.

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