Method for determining the load in a washer-drier and washer-drier

p0001The invention relates to a method for determining the charge amount of laundry in a tumble dryer and a correspondingly shaped tumble.

p0002There are known various ways in which the charge amount can be found in a clothes dryer. From the<patcit id="pcit0001" dnum="EP1067233B1"><text>EP 067 233 B1 1</text></patcit> It is known, for example, to determine a spin cycle and to draw conclusions about the amount of charge.

p0003From the <patcit id="pcit0002" dnum="EP1295979B1"><text>EP 295 979 B1 1</text></patcit> It is known to measure the electrical resistivity or conductivity of the laundry in the dryer. Also, it can be determined the amount of charge in conjunction with the elapsed time. However, since the laundry is always shaken up in the dryer are the measurements inaccurate here.

p0004From the <patcit id="pcit0003" dnum="DE4243594C2"><text>DE 42 43 594 C2</text></patcit> It is known to use both moisture sensors and temperature sensors. From the measurement results, the amount of charge can also be determined. The component cost is substantial.

Problem and Solution

p0005The invention has for its object to provide an aforementioned method and a corresponding dryer with which disadvantages of the prior art can be avoided and, in particular, at limited cost, the charge amount can be determined on laundry in a tumble dryer.

p0006This object is achieved by a method having the features of claim 1, 3 and 6, and by a corresponding tumble dryer with the features of claim 12. Advantageous and preferred embodiments of the invention are the subject matter of further claims and are explained in detail below. Here some of the features are described only once. However, you should apply irrespective of both the procedure and for the correspondingly shaped tumble. The wording of the claims is incorporated by express reference into the content of the description.

p0007The absolute humidity is measured in the air outlet which leads away from the loading space of the laundry dryer. Especially advantageous is the use of the invention in its extraction dryers that blow the moist air to the outside environment, but is not limited thereto. According to the invention at a first fundamental

p0008Embodiment of the invention the amount of charge in the loading space determined that the maximum value and / or the course of the absolute humidity in the air outlet or in the discharged from the cargo space of the laundry dryer, air is determined. These readings are as it were always determined, and when they fall again after an initial increase, the maximum value is just passed. For this purpose usually ranges a single humidity sensor, which keeps the cost of components and assembly time to be limited.

p0009This exploits that there is a relationship between the absolute humidity and the present in the wash water quantity. This amount of water is again, especially with a known residual moisture after the washing process, depending on the amount of laundry, and thus can be concluded that the amount of laundry from the absolute humidity. Under certain circumstances, this can be influenced by the type of laundry, or of the substance. For this purpose, but information can be obtained either from the nature of the selected drying program, which can be seen mainly as a rule, if, for example, cotton laundry to be dried. Furthermore, also, as will be explained below, be tried this residual moisture to be determined more accurately.

p0010In the process of determining the maximum value of the absolute humidity, the individual values ​​are compared and used it the highest or the maximum value. This detecting values ​​may lie in a specific time window. Alternatively, can be assumed that the maximum value is detected when, no further higher value has been detected for a certain period after the highest ever value, for example a few minutes.

p0011Something else is recognized, when the course of the absolute humidity is monitored. Then measurements are not compared with each other regarding their absolute value, but they are compared relative to each other. Is the vast number of successive measured values ​​for the absolute humidity in each case to the preceding, the curve increases. Is the predominant number of measured values ​​under the respectively preceding, the curve decreases. If by establishing a time window of a few minutes is selected, can be also closed by observing the gradient of the curve of the absolute humidity at about the maximum.

p0012The course of the absolute humidity is usually such that it rises sharply after loading with damp laundry and the start of operation. Then falls or he flattens and reaches a rather flat maximum to fall relatively flat from then on. The more wet laundry in the cargo space available, the higher is the maximum value of the gradient, and the flatter it then drops off. The differences between the maximum values ​​in dependence on the amount of charge are so large that they allow determination of the amount of charge on the basis of the maximum value of different, dependent on the amount of charge curves.

p0013The advantage of a provision existing in the load compartment cargo load of clothes is that automatic program sequences can be optimized and better adapted to the actually available amount of charge. This is mainly because the degree of moisture of laundry is usually after a washing process in a relatively narrow range, that is approximately always the same, in particular a residual moisture content of about 50% to 70%, with respect the weight of contained water of the weight Wash. If the amount of charge is known, all of the moisture in the load space can be determined and a program can be adjusted accordingly, in particular in terms of duration, intensity of heating, etc ..

p0014Advantageously, it is possible that values ​​for a correlation maximum values ​​of the absolute humidity are stored with a certain amount of charge. This means that at an assumed given as residual moisture in the laundry is stored a relationship between the maximum value of the absolute humidity and the given quantity of charge, in particular in each case a specific type of dryer. By comparing a control of the dryer existing in the loading space charge quantity can then be determined to wash from the determined by measuring the maximum value of absolute humidity.

p0015In an alternative basic embodiment of the invention, the amount of charge in the loading space according to the invention is determined by the fact that a value of the absolute humidity in the air outlet of the load compartment is determined at a certain defined time after the start of operation of the clothes dryer. Here is advantageously provided that values ​​for the absolute humidity at a given time each correlated with a specific charge amount of laundry are stored in the tumble dryer. In a controller of the clothes dryer may have one comparison carried out by the measured absolute humidity at a specific time and with these stored values. It can then be determined in the load compartment, the amount of charge. For this, as for the aforementioned possibility of the comparison of maximum values ​​of absolute humidity with an amount of charge in the hold, the respective values ​​are determined experimentally for a particular type of dryer, and are then stored in a controller. The aforementioned certain time can advantageously be between 5 minutes and 40 minutes after the start of operation. This takes into account advantageous that in the first 5 minutes of the value of absolute humidity rises still so strong that this behavior is substantially independent of the amount of charge. Only after an even longer time to change the profiles as a function of the amount of charge. the certain time advantageously is about 15 to 20 minutes. In many cases, this date falls after reaching the maximum value, if the course already falls again.

p0016According to a further alternative basic embodiment of the invention, the time is used to determine the amount of charge to the accepts the gradient of the absolute humidity, that is, the slope of the gradient curve, a certain value. Here, too, are in turn advantageous values ​​for a correlation between different values ​​of the gradient stored at certain times with a certain amount of charge dependent. A controller of the clothes dryer, in turn, makes the comparison between the measured and recorded the gradient of the absolute humidity and the time. It can then be determined similarly as before the charge amount of damp laundry in the load compartment.

p0017Particularly advantageously, the time is used for the aforesaid embodiment of the method, to which the gradient of the absolute humidity is negative already again so after reaching the maximum value. The advantage with this method is that a longer time is waited for, for example 20 to 30 minutes. In this time range, the above-mentioned curves for the absolute humidity differ in function of time depending on the amount of charge from one another. Even so, a distinction can be made. It is also possible to use the time at which the gradient of the absolute humidity has become zero. In particular, it may be a time when the gradient thereof is prepared starting again or less drops and is negative.

p0018It can advantageously be provided that the duration of a plateau-like profile of the absolute humidity is determined and the residual moisture is determined that had the laundry after washing and before the drying process. The longer the time duration of the plateau phase, the higher the residual humidity is assumed. Knowing this residual moisture, so you can use this to determine the expected end of the drying process in more detail. The plateau phase can be defined such that during which a deviation of the absolute humidity of 10% is allowed at the maximum value. The course of the absolute humidity is therefore relatively flat.

p0019In the above-mentioned tumble dryer, which is designed to carry out the method described above, is located in the air outlet from the load space, a moisture sensor, such as is generally known and can be seen for example from the above-mentioned prior art. It is connected to a controller of the clothes dryer. This, in turn, is not only configured to detect the measured values ​​of the moisture sensor, but may also be the measuring values ​​or the course record. Furthermore, in a memory of the control the aforementioned values ​​stored for the stated correlations. Finally, the controller advantageously has yet to a timesheet for since the beginning of operation elapsed time.

p0020These and other features will become apparent from the claims and from the description and drawings, and the individual features to be realized in each case alone or together in the form of subcombinations in an embodiment of the invention and in other fields and can represent advantageous, protectable can represent versions, is claimed for which protection. The subdivision of the application into individual sections and the subheadings in no way restrict the statements made thereunder in its generality.

Brief Description of Drawings

p0021An embodiment of the invention is shown schematically in the drawings and will be explained in more detail below. In the drawings:<dl id="dl0001"><dt>Fig. 1</dt><dd>an interior view of a laundry dryer according to the invention and</dd><dt>FIG. 2</dt><dd>a chart for different courses of absolute humidity versus time at various loadings of wash load for the dryer of FIG. 1.</dd></dl>

Detailed description of embodiments

p0022In Fig. 1, an inventive clothes dryer 11 is shown. The description is limited to the parts functionally necessary and is merely intended to illustrate how these functionally important parts of the clothes dryer function. In a loading space 12 is laundry 14 with a residual moisture content after washing or spin. This loading is usually turned or rotated, but this is a minor player in the invention. Via an air inlet 16 air is introduced into the loading space 12th The air flow caused by the fan 17, wherein heated 18 air through the downstream heater is used to dry the laundry 14. Similarly, an air outlet 20 from the loading chamber 12 leads out to the outside, making the clothes dryer 11 identifies as an exhaust air-dryer. The warm air is then, as known of such dryers, the supplied laundry 14 absorbs moisture and transports it via the air outlet 20 to the outside, so as to dry the laundry.

p0023To detect the absolute humidity of the air, a moisture sensor 22 is arranged in the air outlet 20th Such a humidity sensor 22 is known in the art and need not be explained in more detail here. The humidity sensor 22 is connected to a controller 24, as well as the fan 17 and the heater 18. The controller 24 includes a memory 25, possibly integrated, in which various values ​​may be stored, as will be described in detail hereinafter.

p0024Except for a in Fig. 1 shown exhaust air dryer 11, the invention can also be applied to a condensation tumble dryer in a modified form. Given a corresponding humidity sensor is provided in an air outlet of the loading bay against a downstream condenser. So the absolute humidity can there be detected in the air.

p0025In FIG. 2, a plurality of courses of the humidity are plotted against time. The first course is for a case that in the dryer 11 are shown in FIG. 1 in the hold 12 5 kg laundry. The second course is a drying process for 3 kg of laundry and the third course for 1.5 kg. In the first course, it is assumed that a wash residual moisture content of 70% prior to the start of the drying process at time t = 0 is given, for the other two curves, a linen residual moisture content of 50%. The difference between the curves is also recalled that the absolute humidity depends on the air outlet 20 from the surface of the laundry 14th The surface in turn depends on the amount of laundry or the weight. The one wants to determine precisely. So it can be concluded from the level of absolute humidity on the amount of laundry.

p0026It can be seen as the beginning of all three curves are very similar. Only after about 2 minutes, the third profile for the smallest amount of laundry begins to drop in order to reach a maximum at approximately 500 seconds, or about 8 minutes of operation. From this peak it falls into with approximately constant pitch.

p0027This means that at the beginning of the drying process the sensed by the humidity sensor 22 Humidity in the air outlet 20 is independent of the amount of laundry the same. This is especially the fact that it were during the start of the dryer 11 from the laundry 14 maximum thermal humidity is equal both around.

p0028The second course of 3 kg of laundry runs over a longer time equal to the first course, flattens after about 10 minutes from clear to then assume a not quite pronounced maximum value, from which it again drops increasingly steeper after about 16 minutes.

p0029The first course for 5 kg laundry flattens as the second course a little later, namely at about 12 to 14 minutes. It reaches a maximum value at about 30 minutes. In little more than 40 minutes, the course begins, slowly at first and then a little more drops again.

p0030Alone of the three courses for the humidity as a function of time as shown in FIG. 2 it is clear that these courses can be used by an expert to differentiate and thus to determine the amount of charge. Under certain circumstances, it may alternatively or additionally for determining further values ​​such as residual moisture or the like. be used.

p0031In Fig. 2 is shown by dashed lines, where or at what stage a maximum value of humidity is reached. Stored corresponding values ​​can be accessed in the memory 25 of the controller 24th Thus, the controller 24 already determined on the basis of the maximum values ​​of the curves shown in FIG. 2, how much laundry is roughly in the loading chamber 12. , The determination of a maximum value Admittedly, however, particularly in the course of 1, subject to great uncertainty. It need not be accurately controlled to a minute at the method for controlling the laundry dryer. Any inaccuracy should be in a range of a few minutes.

p0032For the second curve with 3 kg of laundry is located spotted, as the course would be if the residual moisture content would be 70% as in the curve for 5kg. However, this course of dots shown only schematically. It is intended to illustrate approximately how instead of recognizable about the maximum of the curve, a wider, plateau similar trend is present as well in the curve for 5kg. Similarly, it would look for the curve with 1.5kg.

p0033It is assumed that the width or duration of the plateau gives some indication of the residual moisture in the laundry after washing. However, this is also to be seen again in comparison to the amount of laundry. So such a plateau phase is for the course at 1.5kg laundry shorter than 5kg laundry. If for example in the curve 2, the residual moisture still higher than that of the dotted representation corresponding 70%, the plateau phase would be extended or longer.

p0034Insofar as the value of absolute humidity after a certain time can be used according to a second, also described above, possibility. In the representation of FIG. 2 is here, for example, a period of about 16 minutes. At this time, the course 1 has not yet reached its maximum value, of course 2 approaches its maximum value and the curve 3 already falls again. As can be seen, the curves at this point or a similar time are sufficiently different in order to be distinguished from each other by comparison.

p0035According to still another possibility, a gradient, or the slope of the curve, particularly at a later time or after exceeding of the respective maximum value, can be detected. For this purpose, either a fixed time can be provided, for example, at about 16 minutes to similarly detect a course that of course 3 yet. This is shown by lines corresponding to the value for the gradient. Furthermore, it is possible, for example, for detecting the attainment of the maximum value to detect the gradient substantially continuously. Once it has become recognizable and permanently negative, it is recognized either the exceeding of the maximum or linked to a detection took place then the gradient with time of this detection, and this in turn compared with corresponding stored values.

p0036According to still another possibility of the invention can be waited by observing the current values ​​for the absolute humidity of the exceeding of the maximum. A certain time thereafter, for example, slightly less than 10 minutes later, is used, then to measure the gradient or slope of the curve. This is also the certainty that a well detectable and comparable value for the gradient is given.

p0037According to still another possibility of the invention may in turn be provided to detect the gradient continuously. It can then be detected the time at which the gradient becomes a certain value. Also by this characteristic, at which time one of the curves shown in FIG. 2 has a certain slope, the profiles can be distinguished from each other and ultimately turn determine the amount of laundry 14 in the loading space 12 of the clothes dryer 11th Through combinations of the aforementioned acquisition opportunities, it is also, among other things possible to draw further conclusions values, such as washing residual moisture at the beginning of the drying process.

p0038Thus, once the amount of laundry 14 is known and possibly the further aforementioned values, the controller 24 regarding the expiry of the drying process. time, air supply and possibly correct temperature air on it. Thus, an be done with regard to output and energy optimized drying process. Furthermore, it is possible that some of the determined values, in particular the amount of laundry and may still a residual moisture of the laundry in the load space 12, on a display of the clothes dryer 11 are displayed as information for a user.