EP2527733B1 - Steam generator for an ironing system - Google Patents

Description

The invention relates to a steam generator for an ironing station, comprising a water tank, a boiler with a radiator for evaporating the water in the boiler, a water supply means for metered supply of water from the tank into a boiling chamber of the boiler, wherein the boiler has a steam outlet for connection of a Steam line to which a handset can be connected, and an outlet means for discharging the water from the boiling chamber for their complete emptying, a control device which is adapted to automatically activate the water supply means, the radiator and the outlet means.

From the document DE 697 06 105 T2 For example, there is known a steam generator for an ironing station comprising a boiler having a boiler attached to a boiling chamber for generating steam communicating with a water tank. From the water tank, the water is metered into the boiling chamber by means of a pump as feeder. The boiler has a steam outlet to which a steam pipe is connected for connection to an iron. For maintenance, a closable outlet opening is arranged in the lower region of the boiling chamber, which is positioned so that an at least almost complete emptying of residual water from the chamber is provided. The emptying must, however, be carried out manually after a predetermined operating time of the steam generator. For convenience or technical ignorance, such maintenance tasks are often not performed regularly or not at all. This can lead to corrosion or limescale or dirt deposits in the boiling chamber, which can reach the ironed at a later stage of operation. Furthermore, excessive corrosion can destroy the boiler or radiator if it is inside the boiling chamber.

From the GB 2 419 607 A is a steam generator with a boiler known, in which the water is conveyed from a reservoir into the boiling chamber of the boiler or can flow into it due to gravity. At the outlet of the reservoir, a filter device is mounted to retain particles and debris. Substances dissolved in the water are not retained.

From the US Pat. No. 7,779,564 B2 a steam generator for an ironing station is known in which automatically after a preset operating time, number of operating cycles or pump running times a rinse cycle for the boiling chamber is performed. Here, the properties of the material of the boiling chamber are not taken into account.

From the DE 199 12 444 A1 a steam generator is known in which the boiling chamber is monitored for limescale deposits. Here, the volume of each individual fillings is recorded. When the amount of water to be filled decreases by a predetermined amount, it is interpreted as a decrease in volume due to lime deposits in the container.

From the CH 656 203 A5 is a designed as a steam boiler steam generator in which by means of a water meter, the amount of water supplied and by means of a timer, the operating time is detected. When reaching a limit value or after expiration of a predetermined operating time in general, a so-called Abschlämmzyklus is driven. From the CH 672 015 A5 and the DE 34 05 212 A1 For example, a steam generator is known which comprises two spaced-apart electrodes which allow current to flow through the water. This will evaporate water. The conductivity of the water is hereby recorded on the basis of the resulting changes in current, and depending on this, residual water emptying is carried out.

The invention is therefore based on the object to provide a steam generator that works permanently reliable and easy to maintain.

According to the invention the object is achieved by a steam generator with the features of independent claim 1 and by a method according to independent claims 11 and 12. Advantageous embodiments and modifications of the invention will become apparent from the respective following dependent claims.

The achievable with the invention advantages are that an inadmissible high concentration of aggressive ingredients in the water is avoided by an automatic and regular complete emptying of the boiler or the boiling chamber. The steam generator can therefore be operated with normal tap water or drinking water as defined in the European Drinking Water Ordinance with regard to the limit values for ingredients. Specially treated water, such as distilled water or demineralized water is not required.

For this purpose, the invention proposes that the control device is adapted to activate the outlet means when a predetermined condition for discharging the water from the boiling chamber is met, wherein the control device is further adapted to perform the discharge of the water without pressure. The controller detects and estimates the amount of water that has been supplied to the boiling chamber based on a record of performed operating cycles. As a predetermined condition can also be an estimate or determination of the amount of water admitted in the boiling chamber over a longer period of time for several cycles of use, taking into account the chloride concentration of the water and / or the material properties of the boiling chamber.

Residual water can not be avoided in a simply constructed steam generator, since continuous steam generation is to be ensured during ironing and a radiator in the boiling chamber must always be covered with water so as not to overheat. The intervals for the emptying of residual water are optimally adapted to the material properties of the boiling chamber and to the actual use or adapted thereto, so that unnecessary waiting times for the emptying of residual water are avoided. Furthermore, corrosion due to accidentally not carried out residual water discharge is also avoided.

In the lower region of the water tank, and here in the region of the box-shaped container shape, a valve arrangement for the automatic emptying of the water tank is arranged in the bottom. So if the water tank is filled and it is used back into the standard unit and here in the bag, so open the valves, so that due to the hydrostatic pressure here, the water can flow into the boiling station. The water can alternatively be pumped out of the tank by means of a pump.

In an expedient embodiment, the controller is configured to activate the heater while the outlet means is activated. As a result, the viscosity of the water is reduced, whereby the residual water flows faster and more completely out of the boiling chamber.

In an advantageous development, the control device is configured to activate the water supply device while the outlet means is activated. As a result, in addition to the removal of residual water, a flushing of the boiling chamber is provided in which liquid residues or deposits adhering to the inner walls are washed out.

In an advantageous embodiment, the outlet means comprises an electromagnetically operable valve. This is particularly easy and reliable with a microcontroller providing the controller to activate.

In another advantageous embodiment, the outlet means comprises an electromotively operable valve. With such a valve, it is particularly easy to provide the pressure resistance, ie the tightness at high pressure in the boiling chamber. In an expedient embodiment, the control device is configured to activate the outlet means after a predetermined period of operation of the radiator. The active times of the radiator can be easily added by a microcontroller, there are no further detection means or sensors necessary.

According to the invention, the control device is configured to activate the outlet means after a predetermined amount of water admitted into the boiling chamber. In this case, the amount of water supplied to the boiling chamber must be recorded with a detection means and recorded for several operating cycles in order to arrive at the total amount of water supplied. In this case, the actual amount of water, which has gradually led to increased contamination of the residual water, is taken into account, whereby the cycles of residual water discharge are carried out very effectively and economically. The normal operation of the steam generator is thus hardly affected due to the rarely performed emptying cycles.

In an advantageous development, the control device is configured to further activate the outlet means when a limit value of an estimated chloride concentration present in the boiling chamber of the boiler is exceeded. The limit values for the chloride concentration to be estimated here are stored in a memory, which is assigned to the control device and can be read by the microcontroller of the control device. For example, the limit is reached when the boiling chamber has been filled a predetermined number. For example, the limit value is reached when the boiling chamber was filled 5 to 10 times, each with a predetermined amount of water, for example in the range of 1 to 2 liters. The limit values for the estimated chloride concentration are permanently programmed into the memory before the steam generator is put into operation. A boiling chamber made of stainless steel has the overall advantage that it is particularly resistant to corrosion. Due to the remaining amount of residual water, as occurs during evaporation with each use, the chloride concentration steadily increases. Since the corrosion behavior depends on the quality of the stainless steel or alloy, it is appropriate to set an individual chloride concentration limit for each alloy used. Depending on the stainless steel quality or alloy actually used, the individual chloride concentration limit value is then activated or set in the control device. The limit value used is the concentration which is higher than the chloride concentration in the tap water used, but is dimensioned to ensure lasting corrosion resistance of the boiling chamber material.

For detecting the amount of water supplied into the boiling chamber, it is expedient to arrange a detection means in the boiling chamber. The detection means comprises a level sensor mounted in the boiling chamber, which in conjunction with the duration of the activity of the water supply means forms a measure of the amount of water supplied. Thus, the microcontroller based on the times in which the water supply device is activated and Carry out a very accurate calculation or determination of the amount of water supplied based on the sensor signal indicating the level in the boiling chamber. Here, the amount of water for several operating cycles of the steam generator is taken into account.

In an overall advantageous embodiment, the steam generator comprises a collecting container for collecting the drained from the boiling chamber water, which can be pulled out for its emptying from a housing of the steam generator or the ironing station. Thus, the draining can be performed by the control device virtually at any time, regardless of a user specification, without causing water damage in the erection area of the steam generator or the ironing system.

To increase safety and reliability of the steam generator further comprises a sensor for detecting a container introduced in the collecting container and another sensor for detecting at least one water level in the collecting container. Thus, the evacuation cycle is performed only when the container is present in the scheduled for the maintenance cycle position and this is also empty.

• Erfassen der Einschaltdauer des Heizkörpers über mehrere Betriebszyklen,
• Aktivieren des Auslassmittels, wenn ein vorbestimmter Grenzwert für die Einschaltdauer überschritten ist.

The invention further relates to a method for operating a steam generator, as described above, with the steps

• Detecting the operating time of the radiator over several operating cycles,
• Activating the exhaust means when a predetermined threshold for the duty cycle is exceeded.

• Erfassen der in die Siedekammer zugeführten Wassermenge für mehrere Betriebszyklen,
• Aktivieren des Auslassmittels, wenn ein vorbestimmter Grenzwert für die der Siedekammer zugeführten Wassermenge überschritten ist.

The invention further relates to a method for operating a steam generator, as described above, with the steps

• Detecting the amount of water supplied into the boiling chamber for a plurality of operating cycles,
• Activating the outlet means when a predetermined limit for the amount of water supplied to the boiling chamber is exceeded.

After activation of the outlet means and complete emptying of the boiling chamber, the outlet means is deactivated again. The boiling chamber is therefore closed again and the control device is set in the initial state, so that the detection of the amount of water supplied to the boiling chamber can start anew. Thus, the maintenance cycle, which in this case includes the complete removal of residual water from the boiling chamber, is performed automatically cyclically, without the user having to think about it.

In an overall advantageous embodiment, the outlet means in the presence of the collecting container and falls below a predetermined water level in Catchment box activated to ensure drained residual water does not leak out of the unit causing water damage.

Overall, it is expedient that after a number of operating cycles in the range of 5 to 10, the outlet means for complete emptying of the boiling chamber is activated. This number has been found in household normal operating cycles, in each of which an amount of water in the range of 0.5 l to 2 l is evaporated, found to be particularly advantageous as protection against excessively high chloride concentration in the residual water.

Overall, the controller or a microcontroller providing the controller is programmed to perform the above method.

Fig. 1

eine Seitenansicht einer Bügelstation in betriebsbereitem Zustand;

Fig. 2

eine schematisches Schaltbild des Dampferzeugers und

Fig. 3

ein Diagramm für den Betrieb des Dampferzeugers.

An embodiment of the invention is shown purely schematically in the drawings and will be described in more detail below. It shows:

Fig. 1

a side view of an ironing station in an operational state;

Fig. 2

a schematic diagram of the steam generator and

Fig. 3

a diagram for the operation of the steam generator.

The FIG. 1 shows an ironing station 1, which comprises an ironing board 2 with a folding frame 3. The frame 3 is in this case arranged on a pillar standing device 4 with a steam generator 6 for an iron 21. As can also be seen, a removable water tank 5 for the steam generator 6 is arranged in the column of the floor unit 4. As further from the FIG. 1 can be seen in an implied manner, the water tank 5 is arranged in an open-access pocket arranged on the column of the standing device 4, which is arranged on the rear wall of the floor unit 4 or on another accessible housing wall.

Within the column-shaped floor unit 4, the steam generator 6 is housed. In this case, below the tank 5, the boiler 7 is arranged, to which a steam line 12 is connected to produce a steam connection to the iron 21. The boiler 7 comprises a heating element for heating and evaporating the water located in the boiling chamber 9. The boiler 7 further comprises an outlet means 13 for discharging residual water from the boiling chamber 9 into a trough-shaped collecting container 16. The control device 14 is adapted to the radiator 8 and the valves of the outlet 13 and the steam supply and the water supply means 10 (FIG. Fig. 2 ) to control. The collecting container 16 can be removed from the housing of the standing device 4 in order to empty it conveniently.

• S1 - Wassertankfüllstand 1 ("Tank leer" und "Tank vorhanden")
• S2 - Wassertankfüllstand 2 (Mindestfüllstand für Spülprogramm)
• S3 - Wasserfüllstand Boiler
• S4 - Wasserfüllstand Abwassertank
• S5 - Abwassertankkontrolle
• S6 - Dampftaste
• SP - Drucksensor mit Schalter (Regelung)
• T1 - Temperaturgrenzschalter für Normalbetrieb
• T2 - Temperaturgrenzschalter für Entkalkungsprozess

Fig. 2 shows a circuit diagram of the steam generator 6. The sensor signals are designated as follows:

• S1 - water tank level 1 ("tank empty" and "tank available")
• S2 - water tank level 2 (minimum level for washing program)
• S3 - Water level boiler
• S4 - Water level waste water tank
• S5 - Waste water tank control
• S6 - steam button
• SP - pressure sensor with switch (control)
• T1 - Temperature limit switch for normal operation
• T2 - Temperature limit switch for descaling process

From the storage tank 5, the water is pumped by means of a pump 10 a, which provides the water supply means in the boiling chamber 9 in the boiler 7. The supply takes place dosed so that no overfilling in the boiling chamber 9 takes place. With the heater 8 mounted in or on the boiling chamber 9, the water is heated and evaporated. A steam valve 11a releases the passage to the steam outlet 11, so that the steam can then pass through the steam line 12 to the handset 21. The user controls the steam demand by means of the steam button S6, which is guided as a signal to the microcontroller uC. The control of the radiator 8 is carried out by a microcontroller uC the control device 14, wherein temperature signals are supplied to the microprocessor with a temperature sensor T1, T2, so that this depending on the sensor signals the radiator 8 on and off or can control level or continuously. Depending on the sensor signal provided by the pressure sensor SP, the steam valve 11a is controlled. As soon as a predetermined pressure is present in the boiling chamber 9, for example in the range of 2 to 6 bar, the valve 11a is released for opening. When the user now actuates the steam button S6, the valve 11a is activated or opened and the steam is released to the steam line 12 or the handset 21, respectively. A pressure relief valve 17 is used for safe pressure reduction when an error occurs and is too high pressure in the boiling chamber 9. The steam generator further comprises an outlet means 13 for discharging residual water from the boiling chamber 9. The outlet means 13 comprises a valve 15 which is actuated electromagnetically or by an electric motor. The microcontroller μC is configured to control this valve 15. In this case, a driver stage can be used, which amplifies the output signals of the microcontroller uC accordingly. Below the boiler 7, the collecting container 16 is arranged, in which the drained water is collected. The collecting container 16 is then removed from the device housing 4 and can then be emptied at a suitable location. The sensor S4 is provided to detect the empty state of the collecting container 16 and to supply the microcontroller μC as a signal. The sensor S5 detects the proper position of the collecting container 16 in the housing 4 and supplies this information as a signal to the microcontroller uC. The microcontroller μC is set up or programmed such that the outlet means 13 or the valve 15 are only actuated is when the collection container 16 is in its predetermined position and is empty. Otherwise, an additional warning message can be issued. The sensors S1 and S2 in the storage tank 5 serve to sense the water level in the tank 5. The microcontroller uC all sensor signals, as outlined with the arrows, fed. Furthermore, the microcontroller uC comprises a programmable, non-volatile memory MEM in which values for the permissible chloride concentration are stored.

h0

Kein Wasser im Boiler (Trockenlauf)

h1

Minimale Wasserhöhe im Boiler (Schaltwert des Füllstandssensors; Pumpe EIN)

h2

Maximale Wasserhöhe im Boiler (Pumpe AUS nach Zeit x)

Cl0

Minimal mögliche Chloridkonzentration

Cl1

Max. zulässige C-Konzentration des Trinkwassers nach TVO (Trinkwasserverordnung)

Cl2

Schaltschwellwert für Ablaufventil

Cl3

Maximale dauerhafte Korrosionsbeständigkeit des Boilermaterials

Clx

Verlauf der Chloridkonzentration im Betrieb

Fig. 3 shows in a time chart the rinsing process in interaction with normal operation. The abbreviations indicate the following states:

h0

No water in the boiler (dry run)

h1

Minimum water level in the boiler (switching value of the level sensor, pump ON)

h2

Maximum water level in the boiler (pump OFF after time x)

cl0

Minimal possible chloride concentration

Cl 1

Max. Permissible C concentration of drinking water according to TVO (Drinking Water Ordinance)

Cl2

Switching threshold for drain valve

Cl3

Maximum lasting corrosion resistance of the boiler material

clx

Course of chloride concentration during operation

The timing is schematically as follows:
At the beginning from time t0, the pump delivers water into the empty boiler 7 or into the boiling chamber 9 of the boiler 7. At time t1, the steam operation DA is started. At time t0, the pump 10a of the water supply device 10 is turned on. The chloride concentration Clx adjusts here to the value Cl1, which corresponds to the concentration of the incoming water. The radiator 8 is switched on from minimum water level h1. At time t2, the pump 10a is turned off, the maximum water level h2 is reached. In the period t2 to t3, the generation of steam is active, so that due to the evaporating water, the water level in the boiler 7 or in the boiling chamber 9 is reduced. As a result, the chloride concentration Clx in the residual water increases, as shown in the lower graph.

In the period t3 to t4, the pump 10a again fills fresh water in the boiler 7 or in the boiling chamber 9, the fresh water is mixed with the residual water and due to the dilution process, the chloride concentration Clx reduced. This process can be repeated several times for several operating cycles BZ. The actual chloride concentration Clx is still below the preset limit value Cl2, so that there is no risk of corrosion for the material of the boiling chamber 9.

At time t6a, the chloride concentration Clx exceeds the preset limit value Cl2, whereby the control device 14 sets a kind of flag to perform a maintenance cycle AB for discharging the residual water and, if necessary, purging the boiling chamber 9 after the start of the next steam cycle.

At the time t9, the ironing process is completed, the maximum permissible chloride concentration Cl2 is now exceeded. Now the execution phase AP is activated. At time t10, the drain valve 15 is opened before the start of the new ironing process or a new cycle BZ and thus the residual water is completely drained from the boiling chamber 9. Subsequently, the outlined procedure can be repeated. The maximum permissible chloride concentration Cl2 is such that it falls below the concentration Cl3 for the maximum permanent corrosion resistance. The limit value Cl3 must never be reached, since at this chloride concentration the corrosion of the material of the boiling chamber begins. As already explained above, the limit value Cl3 is given by the properties or quality of the material used for the boiling chamber 9. The limit value Cl2 is the set or predefined limit value which is dependent on the limit value Cl3 and which is set, selected or programmed in the control device 14 or in the memory MEM of the microcontroller uC.

Claims (14)

1. Steam generator (6) for an ironing station (1), comprising a water reservoir (5); a boiler (7) having a heating element (8) for evaporating the water in the boiler (7); a water supply device (10) for the metered supply of the water from the tank (5) into a boiling chamber (9) of the boiler (7), the boiler (7) comprising a steam outlet (11) for connecting a steam line (12) to which a hand-held device (21) can be connected, and a drainage means (13) for discharging the water out of the boiling chamber (9) in order to empty it completely; a control device (14) which is designed to automatically activate the water supply device (10), the heating element (8) and the drainage means (13), the control device (14) being designed to activate the drainage means (13) when a predetermined condition for discharging the water out of the boiling chamber (9) is met, the control device (14) being further designed to discharge the water without pressure, characterised in that the control device (14) is configured to activate the drainage means (13) after a predetermined amount of water has been admitted into the boiling chamber (9), the control device (14) detecting or estimating the amount of water based on a record of operating cycles carried out.
2. Steam generator according to claim 1, characterised in that the control device (14) is configured to activate the heating element (8) while the drainage means (13) is activated.
3. Steam generator according to either claim 1 or claim 2, characterised in that the control device (14) is configured to activate the water supply device (10) while the drainage means (13) is activated.
4. Steam generator according to claim 1, characterised in that the drainage means (13) comprises a valve (15) that can be electromagnetically actuated.
5. Steam generator according to claim 1, characterised in that the drainage means (13) comprises a valve that can be electromotively actuated.
6. Steam generator according to claim 1, characterised in that the control device (14) is configured to activate the drainage means (13) after a predetermined period of operation of the heating element (8).
7. Steam generator according to claim 1, characterised in that the control device (14) is configured to further activate the drainage means (13) when a threshold value of an estimated chloride concentration (CI2) present in the boiling chamber (9) of the boiler (7) has been exceeded.
8. Steam generator according to claim 7, characterised in that the threshold values for the estimated chloride concentration (CI2) are programmed into a memory (MEM) of the control device (14).
9. Steam generator according to claim 1, characterised by a collecting vessel (16) for collecting the water discharged out of the boiling chamber (9), which vessel can be removed from a housing (4) of the steam generator (6) or the ironing station (1) in order to be emptied.
10. Steam generator according to claim 9, characterised by a sensor (S5) for identifying a collecting vessel (16) inserted into the housing (4) and a further sensor (S4) for identifying at least one water fill level in the collecting vessel (16).
11. Method for operating a steam generator according to any of claims 1 to 10, comprising the steps of:

    - detecting the on-period of the heating element (8) over a plurality of operating cycles (BZ),

    - activating the drainage means (13) when a predetermined threshold value for the on-period is exceeded.
12. Method for operating a steam generator according to any of claims 1 to 10, comprising the steps of:

    - detecting the amount of water supplied to the boiling chamber (9) for a plurality of operating cycles (BZ),

    - activating the drainage means (13) when a predetermined threshold value for an estimated chloride concentration (CI2) is exceeded, after the boiling chamber (9) is filled up to a predetermined level.
13. Method according to either claim 11 or claim 12, wherein the drainage means (13) is activated in the presence of the collecting vessel (16) and when the water in the collecting vessel (16) falls below a predetermined fill level.
14. Method according to either claim 11 or claim 12, wherein, after a number of operating cycles (BZ) in the range of from 5 to 10, the drainage means (16) is activated in order to empty the boiling chamber (9) completely.

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