METHOD OF OPERATING A WASHING MACHINE AND WASHING MACHINE

Abstract

A washing machine has a rotatable drum and drum drive and a drum container for it, an inlet device to introduce water into the drum onto laundry therein, a pump and water pipes, several temperature sensors on the drum container, a heater for heating water and a washing machine controller connected to everything. Laundry in the drum is moistened with a defined quantity of water, wherein the moisture penetration varies depending on the fiber type of the laundry. Then a predefined quantity of water with a predefined temperature is applied to this laundry. The washing machine controller can deduce the fiber type of the laundry from the way how quickly and to what extent heat is extracted from this quantity of water.

Claims

1. A method for operating a washing machine, wherein said washing machine comprises: a rotatable drum with a water-permeable wall including a drum drive for its rotation, a drum container in which said drum is placed, wherein said drum container surrounds said drum, an inlet device to introduce water into said drum onto laundry inside said drum, a pump and water pipes to pump water to said inlet device, at least one temperature sensor on said drum container or on a water pipe, a heating device for heating water, wherein said heating device is connected to said pump in a water-conducting manner, a washing machine controller that is connected to said temperature sensor, said pump, said heater and said drum drive, wherein the following steps are provided: a) dry laundry is placed in said drum or is in said drum, b) a weight of said dry laundry in said drum is known in said washing machine controller, c) said laundry in said drum is soaked, d) a water level in a lower area of said drum container is adjusted by means of said pump so that said drum is not immersed in standing water, e) a predefined quantity of water is brought to a predefined temperature by means of said heating device, f) said predefined quantity of water with said predefined temperature is pumped through said water pipes and through said inlet device into said drum onto said laundry inside, g) water is pumped out of said drum container by means of said pump and is brought into said drum and onto said laundry by means of said water pipes and said inlet device, h) said aforementioned step g) is carried out at least once, or it is carried out until at least twice to five times said predefined quantity of water has been pumped out of said drum container and applied to said laundry, i) a temperature at said temperature sensor is detected and recorded during said application of said water to said laundry, j) in said washing machine controller, temperature curves for temperatures at said temperature sensor are stored in a memory, which have been recorded when carrying out said method according to said steps a) to i) with said same predefined quantity of water and said same predefined water temperature, j1) wherein several groups of temperature curves have been recorded for different weights of said dry laundry in said drum, j2) wherein said stored temperature curves are additionally subdivided into subgroups for at least two different fiber types of said laundry, wherein said method according to said steps a) to i) has been carried out for said subgroups with said same fiber type of said laundry in order to record and store said temperature curves, k) said washing machine controller compares said recorded temperature curves with said stored temperature curves and looks for said greatest match, l) with a corresponding matching weight of said dry laundry, said subgroup of said fiber type of said laundry in said drum is determined by said washing machine controller in said group based on a greatest match between said recorded temperature profile and said stored temperature profiles.

2. The method according to claim 1, wherein two said temperature sensors are provided and are arranged at different vertical heights on said drum container, wherein said temperature sensors are arranged on a water pipe and/or on said drum container, with at least one said temperature sensor being arranged on said drum container.

3. The method according to claim 1, wherein said predefined quantity of water is 0.5 liters to 2 liters.

4. The method according to claim 1, wherein said predefined temperature is 25° C. to 70° C.

5. The method according to claim 1, wherein it takes 1 second to 10 seconds to completely pump said predefined quantity of water out of said drum or out of said drum container through said pump and back into said drum.

6. The method according to claim 1, wherein said drum is rotated at least temporarily or permanently, during said steps f) to h).

7. The method according to claim 6, wherein said drum is rotated at least temporarily or permanently, during said steps f) to h), at a speed of 50 to 1,800 revolutions per minute.

8. The method according to claim 6, wherein said drum is rotated so fast that said water applied to said laundry does not run down inside said drum and through said laundry down into said drum container, but, due to said rotation in said radial direction, passes through said laundry on said outside and through said wall of said drum to said drum container and to said temperature sensor.

9. The method according to claim 1, wherein said water is pumped around continuously by operating said pump.

10. The method according to claim 1, wherein, before said introduction of said predefined quantity of water with a predefined temperature via said inlet device, there is no water in said drum container below said drum in a sump that is formed at a bottom of said drum container.

11. The method according to claim 9, wherein there is also no water in a water pipe between said drum container and said pump.

12. The method according to claim 1, wherein, to heat said predefined quantity of water to said predefined temperature, water corresponding to said predefined quantity is pumped several times by said pump through said heating device without reaching said inlet device or said drum container, and either circulating or with changing direction of flow through said heating device.

13. The method according to claim 12, wherein a water container is provided in said washing machine, from and into which said pump pumps said water in and out again when heating said predefined quantity of water to said predefined temperature.

14. The method according to claim 13, wherein said water container holds at least half of said predefined quantity of water or at least said predefined quantity of water.

15. The method according to claim 1, wherein at least one said temperature sensor is arranged on said pump and/or on said heating device for determining said temperature of said water flowing through or being pumped through and/or for detecting an expended heating energy.

16. A washing machine designed to carry out the method according to claim 1, wherein said washing machine has: a rotatable drum with a water-permeable wall including a drum drive for its rotation, a drum container in which said drum is placed, wherein said drum container surrounds said drum, an inlet device to introduce water into said drum onto laundry inside, a pump and water pipes to pump water to said inlet device, at least one temperature sensor which is arranged on said drum container or on a water pipe behind said drum container, a heating device for heating water, wherein said heating device is connected to said pump in a water-conducting manner, a washing machine controller which is connected to said temperature sensor, said pump, said heating device and said drum drive, wherein said washing machine controller has a memory and is designed to carry out said method according to claim 1.

17. The washing machine according to claim 16, wherein a water container is provided in said washing machine, from and into which said pump pumps said water in and out again when said predefined quantity of water is heated to said predefined temperature.

18. The washing machine according to claim 17, wherein said water container is thermally insulated.

19. The washing machine according to claim 17, wherein said water container holds at least half of said predefined quantity of water or at least said entire predefined quantity of water.

20. The washing machine according to claim 16, wherein said heating device is integrated into said pump.

21. The washing machine according to claim 16, wherein at least one said temperature sensor is arranged on said pump and/or on said heating device for determining said temperature of said water flowing through and/or for detecting an expended heating energy.

22. The washing machine according to claim 16, wherein said temperature sensor is arranged as said first temperature sensor at a level of a lower half of said drum container on an outside of said drum container, and a further temperature sensor is arranged as said second temperature sensor at a level of a upper half of said drum container on said outside of said drum container.

23. The washing machine according to claim 22, wherein said first temperature sensor is located at least 10% of a vertical height of said drum container above a lowest point of the drum container.

24. The washing machine according to claim 16, wherein one said temperature sensor is arranged on a water pipe towards said inlet device and in front of it in a direction of flow.

25. The washing machine according to claim 24, wherein one said temperature sensor is arranged on said water pipe at a distance of less than 10 cm in front of said inlet device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Exemplary embodiments of the invention are shown schematically in the drawings and are explained in more detail below. In the drawings:

[0039] FIG. 1 shows a simplified schematic representation of a washing machine according to the invention with a water supply and several temperature sensors,

[0040] FIG. 2 shows the washing machine from FIG. 1 during the execution of the method according to the invention with application of water to the laundry in a drum,

[0041] FIG. 3 shows courses of temperatures at the temperature sensors for cotton, and

[0042] FIG. 4 shows the courses of temperatures on the temperature sensors for synthetic fibers.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

[0043] FIG. 1 shows a washing machine 11 according to the invention with a rotatable drum 13 in which laundry W is present, shown here as individual items of laundry W. Catches 14 are arranged on the inside of the drum. The drum 13 has a water-permeable outer wall, advantageously perforated as usual, and is rotatably mounted in a drum receptacle 15, here with a horizontal axis of rotation. At the bottom of the drum receptacle 15, a sump line 17 as a water pipe goes from an outlet 16 via a valve V1 to a water reservoir 20. Another pump line 22a leads from this water reservoir 20 to a pump 24. This pump 24 is designed as explained in the prior art mentioned at the outset, for example in accordance with DE 102011003467 A1, advantageously as an impeller pump. It has an integrated heating device 25, which is shown very schematically here. The heating device 25 serves to heat the water conveyed by the pump, in particular in the pump chamber, for which purpose it is advantageously arranged in the pump chamber itself or adjacent to a wall of the pump chamber.

[0044] Another pump line 22b leads from the pump 24 to a three-way valve as pump valve V2. In one valve position, water can go from the pump 24 or the pump line 22b to a water outlet 27 which leads out of the washing machine 11. Water can thus be removed or discharged from the washing machine 11 via the water outlet 27.

[0045] In another position of the pump valve V2, water goes from the pump line 22b via a supply line 29 to an injection nozzle 31 as the aforementioned inlet device, namely with a certain pressure for the water. The injection nozzle 31 is arranged at the highest point of the drum receptacle 15 and is designed in such a way that, although it does not extend directly into the rotatable drum 13, it can apply or spray or mist water F onto the laundry W arranged therein in a known manner through openings provided thereon. In this regard, reference is made to the prior art, which shows this sufficiently well.

[0046] A detergent container 33 is arranged at the top left of the drum receptacle 15, from which detergent or other additives for a washing method can be introduced into the drum receptacle 15 or onto the laundry Win the drum 13 by means of a water pipe 34 and a metering valve V3, alternatively also by means a nozzle, not shown. In yet another alternative, which will be explained below with regard to FIG. 4, detergent can be introduced either into the lowest area of the drum receptacle 15 just before the outlet 16 or into the sump line 17 so that it first mixes with the water or dissolves in it before it is applied to the laundry W. A motor 40 is provided as a drum drive for the drum 13 by means of a drive belt 41, as is known per se. The motor 40 can be controlled as desired.

[0047] FIG. 1 also shows how a first temperature sensor 35 is arranged on the outside of the drum container 15 on the outside on the right and in the lower area. The first temperature sensor 35 is advantageously a standard temperature sensor with a temperature-dependent electrical resistance, for example a PTC, an NTC or a PT100/PT1000, which can measure very quickly and very accurately in the temperature range discussed here. It is advantageously connected to the drum container 15 so that it conducts heat well. It can be arranged at a height of about 20% of the total height of the drum container 14 or the vertical height between the outlet 16 and the top point on the injection nozzle 31. When viewed from the side, it may be located in a central area between the front and rear.

[0048] Further, slightly above the first temperature sensor 35, a second temperature sensor 36 is fixed to the outside of the drum case 15 in the same manner. The second temperature sensor 36 is advantageously of identical design to the first temperature sensor 35. It is located at about 80% of the vertical height of the drum container 15. Seen from the side, it can also be arranged in a central area between front and rear. One of the two temperature sensors would also be sufficient.

[0049] Another third temperature sensor 38, which is advantageously also of identical design to the other two, is additionally arranged on the supply line 29 just before the injection nozzle 31. Its purpose is to record the temperature of the water introduced directly behind it by means of the injection nozzle 31. This can also be done in the pump.

[0050] The three temperature sensors 35, 36 and 38 are connected to a washing machine controller 39, as are the pump 24, the heater 25, the temperature sensor 26 and the motor 40. This connection is also shown for the first temperature sensor 35, but not for the others for the sake of clarity. The washing machine controller 39 can thus measure and record the temperature of the water at the respective point by means of the named temperature sensors 35, 36 and 38, but also by means of the temperature sensor 26, and can also store it if necessary. The washing machine controller 39 advantageously also has a previously described memory, not shown here, for said courses.

[0051] In order to carry out the method according to the invention, as shown in FIG. 2, laundry W is first introduced into the drum 13 in the dry state, for example 3 kg of laundry, according to the definition mentioned at the outset. Either the known weight is entered manually by a user into the washing machine controller 39 or it is determined beforehand by the washing machine controller 39 of the washing machine 11 itself in a manner known from the prior art, for example when the drum 13 is rotating rapidly. Then it is moistened with, for example, 1 liter or 2 liters of water. This can, for example, first run into the drum 13 via a supply line through the detergent container 33 and the metering valve V3 and then be pumped out by the pump 24 and distributed to the laundry W by means of the injection nozzle 31 so that it is drawn into it. This can be done until the pump 24 can no longer suck in water. The retraction can be assisted by rotating the drum 13 slowly or intermittently by means of the motor 40. With the stated quantity of 3 kg of laundry, 1 liter of water will very likely be completely absorbed and little or none of it will run out of the laundry W. Thus, the washing machine controller 39 knows what weight of previously dry laundry is in the drum 13 and what quantity of water has been added to wet it. The defined quantity of 1 liter of water can be adjusted so that it is completely absorbed by 3 kg of dry cotton laundry. With more or less laundry, this quantity of water for wetting through could then be greater or less. With 3 kg of laundry made of synthetic fibers, it may not be able to absorb this defined quantity of 1 liter of water completely, so some of the water runs out again, collects at the bottom of the drum container and runs out or is pumped out. This essentially equal quantity of laundry made of synthetic fibers can then store less water and therefore has a lower thermal capacity when it is soaked through. The heat capacity when wet depends on the type of fibers in the laundry. If one can determine the heat capacity, at least qualitatively, one can deduce the type of fibers.

[0052] The temperature of this water for wetting is advantageously room temperature, i.e., about 22° C. This room temperature can also be determined by the washing machine controller 39 itself using its own temperature sensors, alternatively, for example, using the third temperature sensor 38 just before the injection nozzle 31. Thus, the washing machine controller 39 knows what thermal capacity is present in the drum 13, only the fiber type of the laundry W is not known.

[0053] Then the predefined quantity of water for a batch of warm water, here for example 11, is brought to a predefined temperature, here for example a particularly high temperature for illustration, namely 60° C. In practice, the method is advantageously carried out at the aforementioned lower temperatures, since otherwise it would not be possible in practice to avoid damage to sensitive fiber types as subgroups as a result of temperatures that are too high. Even at these lower temperatures, the temperature curves differ sufficiently. On the one hand, water can be completely sucked out of the drum container 15 via the outlet 16 and the sump line 17 through the outlet valve V1. Additional water can possibly be let in, for example again at the top via a supply line through the detergent container 33 and the metering valve V3. The stated quantity of water of 1 liter can, for example, easily be taken up in the water reservoir 20. Water can be sucked in from the water reservoir 20 by means of the pump 24 and pumped further or upwards into the pump line 22b and also into the feed line 29 adjoining it. The heating device 25 is operated and heats up this water; the temperature of this water can advantageously be detected via a temperature sensor arranged in the pump 24, which is also arranged on the heating device 25, for example, and/or by means of the temperature sensor 26 just behind the pump 24. The pump operation is then stopped and the water pumped up in the lines 22b and 29 can flow back through the pump 24 into the water reservoir 20 again. In this case, it can possibly be heated up again by means of the heating device 25. This process can be repeated several times until the desired temperature of 60° C. is reached. This represents a simple way of bringing a larger predefined quantity of water to a predefined temperature by means of the pump 24 and the heating device 25 on it, which are actually designed for heating in multiple passes. Alternatively, of course, a heating device could also be arranged on the water reservoir 20 in order to bring the predefined quantity of water therein to the predefined temperature and in a quasi-static state. This could in turn be monitored by means of a temperature sensor.

[0054] Then the drum 13 with the laundry W is set in rotation and at the same time the pump 24 pumps the predefined quantity of water at the predefined temperature through the pump line 22b and the supply line 29 by means of the injection nozzle 31 into the drum 13 and onto the laundry W located therein. Here, a speed can be 600 or 800 revolutions per minute, for example. This ensures that the laundry W rests in a distributed manner on the inside of the drum 13; furthermore, water impinging on the laundry W from the inside is pressed through the laundry W and can exit outside through the water-permeable wall of the drum 13. The pumping and application of the water should be relatively strong or abrupt, i.e., it should be done quickly. In FIG. 2 it can be seen how water F, which has previously passed through the laundry W, flows downwards at various points in the drum container 15 towards the outlet 16. The system, including the lines, should be designed in such a way that the water reservoir 20 is empty when water that has just been applied continues to flow from above through the outlet 16 and the sump line 17. This water can then immediately be applied to the laundry W again via the pump line 22b and the feed line 29 by means of the injection nozzle 31 by the continuously operated pump 24, but this time without heating. This is done for a period of 6 seconds to 10 seconds, for example, because it takes that long to apply the predefined quantity of water to the laundry W through the injection nozzle 31. Then the water can either be collected again and again first heated to the predefined temperature according to the predefined quantity of water. This heated quantity of water can then be applied again. Alternatively, water F running off the laundry W immediately can be collected again and pumped back onto the laundry W by the pump 24, which can then take place several times, for example two to five times. Thus, a total of between 2 liters and 5 liters would then have been applied to the laundry W by means of the injection nozzle 31, but only the same predefined quantity of water of 1 liter. This quantity of water is no longer heated. In principle, however, it can also be sufficient to apply the defined heated and predefined quantity of water to the laundry once and then to record the resulting temperature curves.

[0055] It is important that the three temperature sensors 35, 36 and 38 record the temperature of the water on them. For the first alternative, it is shown in FIG. 3 in the diagram over time t, how, with the curve with diamonds, the predefined quantity of water of 1 liter with the predefined temperature of 60° C. is brought into the system of the drum container 15, the drum 13, the soaked laundry W and the lines together with the pump 24, that is pumped by the pump 24 into the pump line 22b. Thus, at the time of t=5 seconds, there is water with a temperature of 60° C. in this system almost instantly, up to t=12 seconds. Here, the pump 24 then stops operating for a few seconds. The curve with the diamonds thus represents the temperature curve at sensor 26. The laundry W here has the fiber type of the cotton subgroup.

[0056] The temperature curves at the three temperature sensors 35, 36 and 38 are also shown. The fastest and highest temperature rise is foreseeable at the third sensor 38 at the top of the injection nozzle 31, since the thrust of warm water according to the predefined quantity of water with the predefined temperature arrives first and virtually without cooling. This temperature profile with the triangles rises very quickly to the same temperature of 60° C., corresponding to the temperature of the predefined quantity of water. If no more water is then pumped in, the temperature remains as high as long as there is water flow.

[0057] The course of the temperature at the second upper temperature sensor 36 with the squares increases somewhat more slowly and only up to about 50° C. This is because this water first has to pass through the soaked laundry items W as a result of the rotation of the drum 13 in order to then be spun onto the drum container 15 in the region of the second temperature sensor 36. This water therefore first gives off part of its thermal energy to the damp and cold laundry; the temperature rises more slowly.

[0058] It is even clearer in the case of the crossed temperature profile at the first temperature sensor 35 that this is even more time-delayed or slowed down and only reaches a maximum temperature of around 30° C. It simply takes longer here until the water that first hits the inside of the drum container 15 at the sensor 36 runs down and past the first temperature sensor 35. Furthermore, this water has already released more of its heat to the drum container 15, which is why an overall significantly lower temperature is recorded there.

[0059] The courses of the temperatures according to FIG. 3 depend, on the one hand, of course, on the delays and also the absolute heights of the structural design of the washing machine 11, especially on the lines 22b and 29, the injection nozzle 31 and the drum container 15 and the drum 13. These conditions are always the same for this washing machine 11 or its type, i.e., other washing machines of the same construction, regardless of the fiber type of the laundry W that is in it. Additional differences between the curves for these temperatures, in particular at the first sensor 35 and at the second sensor 36, are therefore only due to the type of laundry itself. That is why it is also advantageous if, when the quantity of laundry is known, a quantity of water adapted to this is added in order to wet the laundry according to the invention, before the actual method begins with recording the temperatures.

[0060] FIG. 4 shows the temperature curves corresponding to FIG. 3 for laundry W of the same quantity of synthetic fibers. The laundry W here therefore has the synthetic fiber subgroup as the fiber type. Of course, the temperature curve with the diamonds up to 60° C. remains the same. The fastest and highest temperature rise is again foreseeable at the third temperature sensor 38 at the top of the injection nozzle 31. This temperature curve with the triangles rises even faster here to the same temperature of 60° C., corresponding to the temperature of the predefined quantity of water.

[0061] The course of the temperature at the second upper temperature sensor 36 with the squares increases somewhat more slowly than at the third temperature sensor 38, but much faster than in FIG. 3. In addition, the temperature rises to around 55° C. This is even clearer in the case of the crossed temperature profile at the first temperature sensor 35. It's also rising faster here than before, but it reaches a maximum temperature of around 38° C.

[0062] Since the washing machine controller 39 controls the entire method, in particular also the pump 24, it knows when temperature changes are to be expected at which temperature sensors 35, 36 and 38 and possibly also 26, so that the temperature can be recorded. Exemplary curves for the temperature profiles at the temperature sensors 35, 36 and 38 and possibly also 26 are now stored in the washing machine controller 39, depending on the quantity or weight of dry laundry, the water added for wetting, preferably including its temperature, and mainly depends on the fiber type of the laundry. If the quantity or weight of dry laundry is less, the curves for the temperature profiles rise faster, possibly also higher, and vice versa. With cotton as the type of fiber in the laundry, the curves for the temperature gradients rise more slowly, and possibly less steeply, than with synthetic fibers. Such curves for the temperature gradients can also be recorded and stored for other frequently used types of fiber with variation of the aforementioned parameters quantity or weight of dry laundry and quantity of water added for wetting, preferably including its temperature. Such fiber types can be linen, silk and wool and possibly different synthetic fibers as mentioned above.

[0063] Similar methods for using step responses in a system depending on a thermal surge or a sudden increase in temperature are known from DE 102006014515 A1, to which explicit reference is hereby made. There, the temperature in an oven is suddenly increased in order to determine the humidity inside. This humidity largely determines the heat capacity of the air inside.