Operation of a domestic steam treatment device and domestic steam treatment device

Abstract

The method (S1-S6) serves for operating a domestic steam treatment device (1) having an evaporator (4) comprising a heatable water receiving space (5, 7) and a level sensor (6, 11-13) comprising at least two measuring electrodes (6, 12) arranged in a mutual spacing in the water receiving space (5) stacked one above the other, wherein the water recognition measurement values (x_thr) for indicating the degree of wetting of the water (W) filled into the water receiving space (5) by the two measuring electrodes (6, 12) are matched to the conductivity of the water (W) located in the water receiving space (W). The domestic steam treatment device (1) designed accordingly furthermore has a control mechanism (14) which is configured for carrying out the method (S1-S6). The invention is particularly advantageously usable in steamers, in particular ovens and / or microwave devices having a steam treatment function.

Description

Technical Field

[0001] This invention relates to a method for operating a household steam treatment appliance having an evaporator comprising a heatable water reservoir and a level sensor comprising at least two measuring electrodes stacked and spaced apart from each other in the water reservoir, wherein a water identification measurement is set to indicate the degree of wetting of the water filling the water reservoir to the two measuring electrodes. The invention also relates to a corresponding household steam treatment appliance including a control mechanism, wherein the household steam treatment appliance is constructed, particularly when using a control mechanism, for implementing the method. The invention is particularly advantageous for use with steam cookers, especially ovens and / or microwave appliances with steam treatment capabilities. Background Technology

[0002] In the types of level sensors or level measuring devices described herein, there are typically upper and lower measuring electrodes, wherein the lower measuring electrode contacts the filling water earlier than the upper measuring electrode. The lower measuring electrode may be arranged on the bottom side within the water-containing space (e.g., also referring to the area of ​​the bottom itself), while the upper measuring electrode is arranged higher on the side wall of the water-containing space or protrudes into the water-containing space from above. Alternatively, both measuring electrodes may protrude into the water-containing space from above, with the lower measuring electrode protruding further than the upper measuring electrode, and so on.

[0003] For liquid level measurement, a voltage is applied to two measuring electrodes, and the current flowing between the electrodes is measured. Because liquids typically have significantly lower resistance or higher conductivity than air, it is determined whether the water level in the water-containing space has reached and contacted the upper measuring electrode by raising the liquid level sensor reading above a predetermined threshold (hereinafter referred to as the "water identification measurement"). The water identification measurement then corresponds to the sensitivity used to detect reaching the upper measuring electrode: if the reading measured by the liquid level sensor is below the water identification measurement, it is based on the assumption that water has not reached the upper measuring electrode. Therefore, the water identification measurement is set because a leakage current (Kriechströme) flowing between the two measuring electrodes through the filled water cannot be directly observed, as this would incorrectly reflect the water-containing space filled with water up to the upper measuring electrode. Such a leakage current could, for example, flow through the damp inner wall of the evaporator, especially if the inner wall is covered with a porous calcium layer, where water can accumulate.

[0004] DE 10 2014 203 537 A1 discloses an evaporator for steam processing equipment, particularly for household appliances, having a housing with a bottom-side plate heating element for the liquid to be evaporated and a steam outlet, and two electrical contacts exposed in the housing for determining the liquid level in the housing, wherein the plate heating element has at least one unheated area and at least one electrical contact is arranged above the unheated area. Steam processing equipment, particularly steam boilers, have at least one such evaporator.

[0005] WO 2009 / 007456 A3 discloses an apparatus for adding water for generating steam in a cooking appliance, comprising: an evaporator container into which water can be supplied according to the level of water contained in the evaporator container; and an electrode for detecting the level of water in the evaporator container, wherein the inner wall of the evaporator container is at least partially made of a conductive material and such portion of the inner wall is the first electrode.

[0006] However, it has been shown that the operation of evaporators in household steam treatment equipment can be unsatisfactory depending on the type of water used. Summary of the Invention

[0007] The object of the present invention is to at least partially overcome the shortcomings of the prior art and, in particular, to provide an improvement for the evaporator of a household steam treatment device operating in situations where different types of water (e.g., tap water, distilled water, etc.) are used.

[0008] This objective is achieved according to the features of the independent claim. Advantageous embodiments are the subject of the dependent claims, the description, and the drawings.

[0009] This objective is achieved by a method for operating a household steam treatment device having an evaporator including a heatable water containment space and a level sensor including two measuring electrodes stacked and spaced apart from each other in the water containment space, wherein water identification measurements indicating the degree of wetting of the water filling the water containment space by the two measuring electrodes are matched with the conductivity of the water in the water containment space.

[0010] This provides the advantage that a defined water filling height is achieved in the water-containing space—determined by a direct electrical connection between two measuring electrodes via the filled water—within a wide range of water conductivity that can be reliably detected. If the water is very soft (e.g., with a conductivity of less than 50 μS / cm), the evaporator can also be operated as specified. Such very soft water can be, for example, distilled water, permeate, or deionized water (“purified water”). This method is also advantageously cost-effective because existing components of a known evaporator with the structure involved can be used without modification, and software matching is readily achievable. The evaporator can, for example, have the structure described in DE 10 2014 203537 A1, the contents of which are fully adopted.

[0011] This method is based on the understanding that unsatisfactory evaporator operation sometimes occurs when water with a significantly lower conductivity than water with a commonly used conductivity (“standard conductivity,” such as drinking water from a tap). This standard conductivity can be set or selected, for example, from the factory, through customer service, or by the user. Because in the case of water with a significantly lower conductivity than the standard conductivity, if the filling water contacts the two measuring electrodes, the (current) measurement obtained by the level sensor is itself less than the water identification measurement achieved according to the standard conductivity. Therefore, the household steam treatment equipment may incorrectly fail to identify sufficient filling of the water container. Consequently, the household steam treatment equipment will not operate the evaporator as intended. This problem is avoided by matching the water identification measurement to the conductivity of the filling water.

[0012] Steam processing equipment can be a steamer. A steamer can be a standalone device or a combination of devices, such as an oven and / or microwave oven with steam processing capabilities.

[0013] An evaporator can be located outside the processing space that supplies the items to be steamed. However, an evaporator can also be located within the processing space, for example, suspended in a side wall.

[0014] The processing space can be a cooking space for processing cooked items. In the case of a furnace, the cooking space can also be called a furnace space. Water in the water-containing space can be heated, particularly until boiling, by activating a heating device (e.g., with a power of up to 1200 watts) provided to the evaporator. The evaporated water can be guided to the processing space via a steam conveying device. For temperature setting or regulation, a temperature sensor can be provided to the evaporator to determine the temperature of the water in the water-containing space.

[0015] During steam generation operation (e.g. for steam cooking), the evaporator can be operated such that if the measured value determined or measured by the level sensor is below the water identification measurement value, then water is refilled into the water holding space until the water identification measurement value is reached or exceeded again, and if necessary, a determined additional volume is added, for example by a delayed shutdown of the pump.

[0016] The water holding space of the evaporator is advantageously filled with water via a water tank that can be arranged in a domestic steam handling unit. Filling can be carried out, for example, by the activation of a pump or by the opening of a valve and the subsequent flow of water from the tank by gravity. The water tank can be removable or fixedly installed in the unit. In one variant, the water tank can be filled by the user, especially if the tank is removable. In another variant, particularly advantageous for non-removable water tanks, the tank is automatically filled, for example, via a fresh water inlet. The capacity of the water tank is typically many times greater than the capacity of the water holding space.

[0017] Liquid level sensors are particularly useful in connection with the control mechanisms of domestic steam treatment equipment, which also control the filling of water-containing spaces. The measurement signals recorded by the liquid level sensor can be digitized or can be digitized and subsequently exist as (digital) measurements in corresponding units or "digital components." The measured values ​​are correlated with, and are in particular proportional to, the current flowing between the measuring electrodes. For example, the measured values ​​can be configured such that one unit corresponds to approximately 1 milliampere.

[0018] Water identification measurements are matched to the conductivity of water located in the water-containing space, including: this can be implemented either without intermediate connection and user processing or automatically.

[0019] Conductivity for very soft water (e.g., fully desalinated water, permeate, deionized water, distilled water, etc.) is typically between 1 μS / cm and 100 μS / cm, while for normal drinking water according to drinking water standards, it falls within the entire hardness range (temperature-dependent) between 100 μS / cm and 2500 μS / cm. In particular, if the conductivity is less than 50 μS / cm, problems may arise during evaporator operation when setting up water identification measurements for drinking water according to drinking water standards, as the contact between the two measuring electrodes through the filling water may not be reliably detected.

[0020] If, for example, for applications involving water conforming to drinking water standards, the water identification measurement is set to 450 units or a "digital composition" (e.g., based on a determined current), then leakage current through water paths different from the filling water (e.g., through damp inner walls) can be reliably ruled out, because leakage current in practice does not reach 450 units. If, instead of filling the water tank with drinking water, very soft water with a conductivity of, for example, less than 50 μS / cm is filled (e.g., because the user has already filled the tank with distilled water without matching factory settings), then it is possible that the current passing between the two measuring electrodes, even when immersed in the filling water, does not reach the preset water identification measurement of 450 units. The device logic then concludes that the water has not reached its designated filling height, even if it actually has.

[0021] One design involves matching the water identification measurement value to the conductivity of the water located in the water-containing space during the process:

[0022] (a) Set the water identification measurement value to the predetermined minimum value;

[0023] (b) Fill the water-containing space with water until the minimum value is reached or exceeded;

[0024] (c) To cause the water in the water-containing space to boil;

[0025] (d) Determine the corresponding measurement value using a liquid level sensor;

[0026] (e) Match the water identification measurement with at least one measurement determined in step (d).

[0027] This method has the advantage that it reliably produces a wide range of water identification measurements that can be matched to conductivity, which is sufficient even without a specific calculation of the conductivity of water and even without knowing the conductivity.

[0028] The matching process can be automated. It can be triggered automatically by the device, by the user, or by service technicians.

[0029] The minimum value set in step (a) is determined such that, particularly assuming no or only small leakage current, the degree of wettability of the two measuring electrodes is also identified in step (b) for very soft water (e.g., having conductivity between 1 μS / cm and 100 μS / cm, particularly between 1 μS / cm and 50 μS / cm). The filling water is typically cold water, for example, having a temperature in the range of room temperature (25°C) or lower. The minimum value is particularly above zero, for example, in 40 measurement units or digital components.

[0030] The minimum value can be so small that the leakage current, which typically occurs during steam generation operation, will have a high measured value. Therefore, one design option is to implement step (b) in the case of a dry evaporator. This could be the case, for example, if the evaporator cannot be operated for a sufficiently long duration (e.g., at least one day).

[0031] By heating the water in step (c) to at least approximately the boiling point (e.g., reaching a temperature between 95°C and 100°C), it is advantageously ensured that the water's conductivity within the same temperature range is as in typical steam-generating operation. This is based on the consideration that the conductivity of water is highly temperature-dependent. Thus, conductivity typically increases by approximately 2% for every 1°C increase in temperature. The boiling temperature can also be advantageously and particularly reliably reached compared to lower temperatures, and more precisely, even without the use of a temperature sensor. This can be achieved, for example, by time control (e.g., 45 seconds) or temperature control (e.g., in the presence of a temperature sensor). However, it is generally possible to set another temperature higher than the boiling temperature, especially if that temperature is adjustable.

[0032] Determining at least one associated measurement in step (d) includes recording one or more measurements in the case of hot water. An improvement is that the measurement is determined or obtained, particularly as an average, by means of a series of individual measurements recorded over a predetermined measurement duration (e.g., between 5 and 10 seconds). This yields the advantage that the measurement can be determined particularly reliably because, for example, fluctuations caused by the movement of individual measurements across the surface are suppressed.

[0033] The measurement determined in step (d) can correspond to the actual liquid level, which, especially in the case of very soft water, is significantly higher than the lower end (“height”) of the upper measuring electrode. The higher the conductivity of the water, the better the measurement corresponds to the height of the upper measuring electrode.

[0034] The matching in step (e) includes checking which water identification measurement is suitable for the measurement determined in step (d). If the water identification measurement thus obtained does not correspond to the minimum value, then the obtained water identification measurement is adjusted or accepted as the new water identification measurement. Advantageously, the water identification measurement is less than the measurement determined in step (d).

[0035] One design involves matching the water identification measurement value in step (e) using a formula or characteristic curve that provides the relationship between the measurement value determined in step (d) and the water identification measurement value. This allows the water identification measurement value to be adjusted, particularly linearly, using the measurement value as an input parameter. The formula, its parameters, and the data in the characteristic curve (or table) can be determined beforehand through experimentation, for example, by the manufacturer of the household steam treatment equipment. The formula may, for example, represent a predetermined difference from the measurement value determined in step (d) or a predetermined fraction of the measurement value determined in step (d).

[0036] One design involves, in step (e), if the measurement value determined in step (d) exceeds a predetermined threshold, then the water identification measurement value is set to a first, higher value; otherwise, it is set to a second, lower value. Therefore, it is checked whether the measurement value associated with water identification in the water-containing space is lower (below the predetermined threshold, e.g., if very soft water is filled) or higher (above the predetermined threshold, e.g., if water is filled according to drinking water regulations). Based on this, the water identification measurement value is set to a lower (e.g., for very soft water) or a higher (e.g., for water according to drinking water regulations) value. These two water identification measurement values ​​are fixed and predetermined. However, in principle, it is also possible to apply more than two types or values ​​instead of these two, for example, in the case of using two thresholds and accordingly setting low, medium, and high water identification measurement values. This at least one threshold can also be referred to as a "hardness boundary."

[0037] One design approach involves performing the following steps after step (d) and before step (e):

[0038] (d2) Remove water from the water-containing space until it is below a predetermined small fraction A of the measured value determined in step (d) by means of a level sensor;

[0039] (d3) Then, another measurement value is determined using a liquid level sensor;

[0040] Furthermore, the water identification measurement value in step (e) is set to a value between the measurement value measured in step (d) and another measurement value measured in step (d3). This achieves the advantage that the water identification measurement value is calculable even without characteristic curves or complex formulas. The measurement value determined in step (d) can also be called the "upper measurement value," and the other measurement value determined in step (d3) can also be called the "lower measurement value." This design takes full advantage of the fact that if the electrodes are no longer in electrical contact with the water, the measurement value measured by the level sensor decreases relatively abruptly when water is removed from the water-containing space (e.g., pumped away or allowed to flow out). A small portion A can be arbitrarily chosen in principle; however, it is advantageous to determine that the lower measurement value typically describes the situation where the two measuring electrodes are reliably no longer electrically connected to each other through the filling water, but a large volume of water still exists in the water-containing space. The lower measurement value thus at least roughly depicts the leakage current present during steam-generating operation. The lower measurement value, or leakage current, can be significantly below the upper measurement value multiplied by a small portion A.

[0041] The predetermined coefficient or a small portion of A is advantageously located in the range of [0.1; 0.5], especially [0.1; 0.3], especially [0.25; 0.15], for example, in about 0.2.

[0042] In step (d2), the corresponding lower measurement value can be determined similarly to the upper measurement value, for example, as the average value of a measurement sequence recorded over a predetermined time interval (e.g., between 5 and 10 seconds).

[0043] The water identification measurement value x_thr can be set to the following value in step (e), for example:

[0044] x_thr = (x_o - x_u) * B + x_u

[0045] or

[0046] x_thr = x_o - (x_o - x_u) * B,

[0047] Where x_o represents the upper measurement value, x_u represents the lower measurement value, and B represents a suitable coefficient, particularly from the value range [0; 1]. It has been shown that values ​​of B from the value range [0.4; 0.6], particularly 0.5, are particularly suitable.

[0048] The degree of contamination, particularly calcification, can also be inferred from the measured value (or any other measurement that essentially only measures leakage current); the higher the measured value of leakage current, the higher the contamination, particularly calcification, of the evaporator. An improvement is that if the measured value of leakage current exceeds a predetermined threshold, at least one action involving decalcification is triggered. This action could include, for example, outputting to the user, triggering a decalcification process, and / or automatically implementing the decalcification process. The threshold (also referred to as the "calcification identification threshold") can be fixed or predetermined, or it can be determined based on a value determined accordingly after the decalcification process, for example, as a fixed or percentage difference from the value determined after the decalcification process. The calcification identification threshold can also be determined alternatively from historical data.

[0049] The above method is advantageously implemented when the evaporator is not yet or no longer contaminated, especially calcified (in a new state / or after a decalcification process using sufficient rinsing). This method can be repeated using identified events, such as after a change in water hardness, after a "pump rest" triggered by customer service, time-controlled (e.g., every three months), and / or after resetting to factory settings. Thus, a pump rest, for example, indicates an error under which it is determined that the pump has been running for too long to fill the water reservoir. If very soft water is filled into the water reservoir without matching water identification measurements, then, for example, this can occur: subsequently, that is, water is not identified or not identified to a sufficient degree, and the pump remains active even though both electrodes have been wetted with water.

[0050] One design involves determining the presence of a calcium remover if the measured value identified in step (d) exceeds a predetermined threshold. This leverages the fact that calcium removers significantly increase conductivity. Therefore, measurements above the threshold (also referred to as the "calcium removal threshold") are likely caused by the presence of a calcium remover in the water. The calcium removal threshold could be, for example, 2000 μS / cm or higher, as conductivity typically falls between 2000 μS / cm and 50000 μS / cm in the presence of a calcium remover.

[0051] One design involves determining a predetermined (calcification) threshold during a separate decalcification process, and if the presence of a decalcifying agent is determined, then implementing at least one rinsing process for the rinsing water containment space, particularly using clean water (without a decalcifying agent).

[0052] This objective is further achieved by a household steam treatment device having an evaporator comprising a heatable water containment space and a level sensor comprising at least two measuring electrodes stacked and spaced apart from each other in the water containment space, wherein a control mechanism is configured to implement the method as described above. The household steam treatment device can be constructed similarly to the method, and vice versa; and has the same advantages.

[0053] Such a design solution involves using a steamer as the household steam treatment equipment. Attached Figure Description

[0054] The above-described features, characteristics, and advantages of the present invention, and how to achieve them, become clearer and more readily understood in conjunction with the following illustrative description of an embodiment, wherein the embodiment is further illustrated in conjunction with the accompanying drawings.

[0055] Figure 1 A sketch of a domestic steam treatment unit is shown in the side view as a cross-sectional view.

[0056] Figure 2 A graph showing the measured value x sensed by the level sensor relative to time t for a possible matching process; and

[0057] Figure 3 A possible flow diagram is shown for a method to match water identification measurements. Detailed Implementation

[0058] Figure 1 A sketch of a household steam treatment device in the form of an oven 1 with steam treatment function is shown as a cross-sectional view in the side view. The oven 1 has a cooking space 3 defined by a cooking space wall 2. Outside the cooking space 3 is an evaporator 4 with a water-containing space 5. The water-containing space 5 has a metal plate on its bottom side, which is heatable by means of an electric heating device 7. The water W located in the water-containing space 5 can be heated by means of the metal plate, specifically until it boils. The steam generated here reaches the cooking space 3 through a steam conveying device 8.

[0059] Water W can be filled into the water-containing space 5 from the bottom side by means of pump 9, or more precisely, from a removable water tank 10. The capacity of the water tank 10 is typically many times greater than the capacity of the water-containing space 5. Pump 9 can also be operated in such a way that water W can be pumped from the water-containing space 5 back into the water tank 10 by means of pump.

[0060] The evaporator 4 also has a level sensor 11, or is equipped with a level sensor 11. The level sensor 11 has a metal plate as a lower measuring electrode and an upper measuring electrode 12 protruding into the water-containing space, both connected to an analysis circuit 13. A voltage is applied to the metal plate and the upper measuring electrode 12. The analysis circuit 13 is connected to a control mechanism 14, which can also control the operation of the pump 9 and the heating device 7. In a variant, the analysis circuit 13 can be integrated into the control mechanism 14, thus the control mechanism 14 assumes the function of the analysis circuit.

[0061] When water W is filled into the water-containing space 5, the metal plate is first covered with water W. As the liquid level rises, water W also comes into contact with the upper measuring electrode 12, thereby causing a jump in the current flowing between the measuring electrodes 6 and 12. In the case of a dry evaporator 4, there is mostly no or only a small parasitic leakage current through the damp inner wall of the evaporator 4. If the evaporator 4 is damp, for example, based on the current steam generation operation, then this leakage current can become significantly large. To avoid the influence of leakage current, a water identification measurement value is advantageously set or determined in the analysis circuit 13, which is greater than zero and greater than the measurement value based on the leakage current, but less than the measurement value based on the contact of the filling water W.

[0062] This works well for a long time, as if the water identification measurement value is in harmony with the conductivity of the water W being filled. However, if very soft water (e.g., with a conductivity of less than 50 μS / cm) is filled into the water tank 10, although the water identification measurement value is adapted to harder water (e.g., with a conductivity of 100 μS / cm or greater), it is possible that the water identification measurement value is not reached at all, even if the upper measuring electrode 12 has been clearly immersed in the water W being filled.

[0063] Figure 2 A graph is shown showing the measured value x (corresponding to the current flowing between measuring electrodes 6 and 12) sensed by the level sensor 11 relative to the time t for a possible matching process.

[0064] First of all, as in Figure 3 As further described, in step S1, the water identification measurement value x_thr is first adjusted to its minimum value x_thr_min. The minimum value x_thr_min is selected, for example, such that the identification measurement electrodes 6, 12 are reliably identified through direct contact with water W having a conductivity between 1 μS / cm and 50 μS / cm.

[0065] In step S2, since time t0, cold water W is pumped from water tank 10 to water storage space 5 by pump 9, wherein since time t1, the presence of water W between measuring electrodes 6 and 12 causes a jump increase in the measured value x.

[0066] Pump 9 is operated until the measured value x sensed by level sensor 11 reaches or exceeds the minimum value x_thr_min at time t2, and then it is shut off in step S3. Based on the short restart of pump 9, some water W is also pumped in after the minimum value x_thr_min is reached, thereby slightly increasing the measured value x. This restart can also be selectively configured.

[0067] Preferably, steps S1 to S3 are performed in the case of a dry evaporator 4, because this avoids leakage current through, for example, a damp inner wall that may be covered with calcium.

[0068] In step S4, since water W boils by turning on heating device 7 at time t3, the electrical conductivity of water W and thus the measured value x are increased at least approximately proportionally.

[0069] At time t4 (e.g., 45 seconds after time t3), water W reliably reaches its boiling point, and heating device 7 is turned off.

[0070] In step S5, a series of individual measurements x are now measured over a measurement duration of t4 to t5, for example, 5 to 10 seconds, and an average measurement x_o is determined therefrom.

[0071] Subsequently, in step S6, a new water identification measurement value x_thr = x_thr_new is calculated based at least on the average measurement value x_o determined in step S5, and is then set in the analysis circuit 13.

[0072] In one variant, the water identification measurement value x_thr_new can be calculated using characteristic curves or formulas.

[0073] In another variation, after determining the average measured value x_o (which can also be called the upper measured value) in step S5b, water W is pumped out of the water holding space 5 until it is below a lower value x = A • x_o, where a small portion of A can take a value in the range [0.1; 0.5], for example 0.2.

[0074] Subsequently, in step S5c, an average value x_u (also referred to as the lower measurement value) is measured, similar to the average measurement value x_o. The average value x_u can specifically correspond to the leakage current.

[0075] In step S6, the new or matching water identification measurement value x_thr_new is set to a value between x_u and x_o.

[0076] This concludes the matching process.

[0077] During subsequent steam generation, water W is pumped back into evaporator 4 until the level sensor 11's measurement x reaches or exceeds the water identification measurement x_thr_new. Then, heating device 7 is activated to boil the water W, and the evaporated water W is delivered to cooking space 3 via steam delivery device 8. If the level sensor 11's measurement x drops below the water identification measurement x_thr_new, water W is pumped back in while heating device 7 is activated until the water identification measurement x_thr_new is reached or exceeded again, and so on.

[0078] If the water identification measurement value x_thr is set to a value intended for harder water during steam generation operation, it is possible that the level sensor 11 will no longer reach the water identification measurement value x_thr when using very soft water W. Subsequently, for example, a pump stop error can be reported, and the evaporator 4 can be shut down.

[0079] Of course, the present invention is not limited to the embodiments shown.

[0080] Thus, by analyzing the measured value x of the liquid level sensor 11, it can also be determined whether a calcium removal agent is present in the water W.

[0081] Generally, "one," "one," etc. can be understood as singular or plural, especially in the sense of "at least one" or "one or more," as long as this is not explicitly excluded, for example by expressing "exactly one," etc.

[0082] Numerical specifications may also include the exact figures provided, as well as the usual tolerance range, unless this is explicitly excluded.

[0083] List of reference numerals

[0084] 1 oven

[0085] 2. Cooking space wall

[0086] 3 cooking spaces

[0087] 4 Evaporators

[0088] 5 water storage space

[0089] 6 measuring electrodes

[0090] 7 Heating device

[0091] 8 Steam conveying device

[0092] 9 pumps

[0093] 10 water tanks

[0094] 11 Liquid Level Sensor

[0095] 12 Measuring electrodes

[0096] 13 Analysis Circuit

[0097] 14 Control mechanisms

[0098] S1-S6 Method Steps

[0099] t time

[0100] t1-t5 time points

[0101] W water

[0102] x measurement value

[0103] x_o average measurement / upper measurement

[0104] x_thr water identification measurement value

[0105] minimum value of x_thr_min

[0106] x_thr_new New water identification measurement value

[0107] x_u average measurement / lower measurement.

Claims

1. A method (S1-S6) for operating a household steam treatment device (1), the household steam treatment device having an evaporator (4) including a heatable water containment space (5) and a level sensor (11) including at least two measuring electrodes (6, 12) stacked and spaced apart from each other in the water containment space (5), wherein a water identification measurement value (x_thr) indicating the degree of wetting of the two measuring electrodes (6, 12) with respect to the water (W) filling the water containment space (5) is matched with the conductivity of the water (W) located in the water containment space (5), wherein, During the matching process: (a) The water identification measurement value (x_thr) is set to a predetermined minimum value (x_thr_min) (S1); (b) Fill the water-containing space (5) with water (W) (S2) until the minimum value (x_thr_min) is reached or exceeded (S3); (c) The water (W) in the water-containing space (5) is brought to a boil (S4); (d) Determine the corresponding measurement value (x_o) by means of the liquid level sensor (11) (S5); (e) Match the water identification measurement (x_thr) with the measurement (x_o) determined in step (d) (S6).

2. The method according to claim 1 (S1-S6), wherein, Step (b) (S2, S3) is performed in the case of a dry evaporator (4).

3. The method according to claim 1 or 2 (S1-S6), wherein, In step (e), the water identification measurement (x_thr) is matched (S6) by a formula or characteristic curve, which provides the relationship between the measurement (x_o) determined in step (d) and the water identification measurement (x_thr, x_thr_new).

4. The method according to claim 3 (S1-S6), wherein, In step (e), if the measurement value (x_o) determined in step (d) exceeds a predetermined threshold, then the water identification measurement value (x_thr) is determined to a first, higher value; otherwise, it is determined to a second, lower value (S6).

5. The method according to claim 1 or 2 (S1-S6), wherein, After step (d), perform the following steps: (d2) Remove water from the water-containing space until the level sensor (11) is lower than a predetermined fraction of the measured value (x_o) determined in step (d) (S5b). (d3) Then, another measurement value (x_u) is determined by means of the liquid level sensor (11) (S5c); And the water identification measurement value is set in step (e) to a value between the measurement value (x_o) measured in step (d) and another measurement value (x_u) measured in step (d3) (S6).

6. The method according to claim 1 or 2 (S1-S6), wherein, If the measured value (x_o) determined in step (d) exceeds a predetermined threshold, then the presence of a calcium remover is determined.

7. The method according to claim 6 (S1-S6), wherein, During the decalcification process, the predetermined threshold is determined, and if the presence of the decalcification agent is determined, at least one flushing process for rinsing the water-containing space (5) is performed.

8. A household steam treatment device (1) having an evaporator (4) including a heatable water containment space (5) and a level sensor (11) including two measuring electrodes (6, 12) stacked and spaced apart from each other in the water containment space (5), and further having a control mechanism (14), wherein the household steam treatment device (1) is configured to implement the method (S1-S6) according to any one of the preceding claims when using the control mechanism (14).

9. The household steam treatment device (1) according to claim 8, wherein, The household steam treatment equipment (1) is a steamer.

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