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EP-4741555-A1 - METHOD FOR OPERATING A WASHING MACHINE AND WASHING MACHINE

EP4741555A1EP 4741555 A1EP4741555 A1EP 4741555A1EP-4741555-A1

Abstract

The invention relates to a method for operating a washing machine with a tub (1) for holding water, a drum (2) rotatably mounted in the tub (1) for holding laundry (4), a heating element (3) for heating the water, a circulation system for transferring water from a first area of the tub (1) to a second area of the tub (1), and a control and/or regulating device for controlling and/or regulating a washing program, comprising a heating process during the execution of a washing program, wherein the water level in the tub (1) is controlled and/or regulated during the heating process such that the water in the tub is simultaneously heated by the heating element (3) and transferred by the circulation system from the first area of the tub (1) to the second area of the tub (1). The invention further relates to a corresponding washing machine.

Inventors

  • Holtkötter, Jens
  • SIEDING, DIRK

Assignees

  • Miele & Cie. KG

Dates

Publication Date
20260513
Application Date
20251014

Claims (10)

  1. Method for operating a washing machine with a tub (1) for holding water, a drum (2) rotatably mounted in the tub (1) for holding laundry (4), a heating element (3) for heating the water, a circulation system for conveying the water from a first area of the tub (1) to a second area of the tub (1) and a control and/or regulating device for controlling and/or regulating a washing program, comprising a heating process during the execution of a washing program, wherein the water level in the tub (1) is controlled and/or regulated during the heating process such that the water in the tub is simultaneously heated by means of the heating element (3) and conveyed by means of the circulation system from the first area of the tub (1) to the second area of the tub (1).
  2. Method according to claim 1, characterized in that the water level in the lye container (1) is controlled and/or regulated in the heating process by adjusting a volume flow conveyed by the circulation system and/or a rotation rhythm of the drum (2).
  3. Method according to claim 1 or 2, characterized in that the heating process comprises the following steps a) Setting a 100% actual saturation in the laundry (4) located in the drum (2) by adding water to the tub (1), b) Adding more water as free liquor so that the water level in the lye container (1) is above the heating element (3) and below the drum (2), c) Rotating the drum (2) according to a selected speed profile, d) Impulsive introduction of the free fleet into the laundry (4) with activation of the recirculation system, e) Deactivating the activated bypass system when a minimum water level is reached in the lye tank (1), resulting in a specific discharge volume flow corresponding to the rotational speed profile and a rise in the water level, f) Starting a time measurement following step e), as soon as a predetermined starting water level is reached, g) Stopping the timer as soon as a predetermined stop water level or a predetermined time limit is reached, h) Calculating the specific discharge volume flow rate using a result from a time measurement, and i) Increasing the calculated specific discharge volume flow rate to its final value in order to maintain a continuous water level with the heating element (3) and recirculation system activated simultaneously.
  4. The method of claim 3, characterized in that the following steps are carried out during and/or following step i): - Measuring the actual pressure, - Calculating a target volume and an actual volume of the free fleet based on a target pressure and the measured actual pressure and a pressure-volume characteristic curve, - Calculating the difference between the calculated actual volume and the calculated target volume, and - Using the calculated difference as a control variable to regulate a target rotational speed of the drum (2) at which a continuous water level is achieved with the heating element (3) and the recirculation system activated simultaneously.
  5. Method according to claim 4, characterized by determining a time in which the calculated difference is used as a controller control variable, based on gain factors of a controller (5) that regulates the target rotational speed.
  6. Method according to one of the preceding claims 4 or 5, characterized by summing the calculated discharge volume flow rate and the controller control variable and performing a control variable limitation of the sum corresponding to a delivery capacity of the recirculation system.
  7. Method according to claim 6, characterized by performing an antiwindup.
  8. Method according to any one of the preceding claims 3 to 7, characterized in that step c) is further divided into a speed profile different from the speed profile. The speed profile and steps d) to g) are repeated, or another heating process is set, if in step g) the time measurement is stopped by the predetermined time limit.
  9. Method according to one of the preceding claims 4 to 8, characterized in that the target rotational speed is calculated on the basis of a flow characteristic curve and the calculated discharge volume flow rate.
  10. Washing machine with a tub (1) for receiving water, a drum (2) rotatably mounted in the tub (1) for receiving laundry (4), a heating element (3) for heating the water, a circulation system for conveying the water from a first area of the tub (1) into a second area of the tub (1) and a control and/or regulating device for controlling and/or regulating a washing program and a method according to one of the preceding claims.

Description

The invention relates to a method for operating a washing machine and a washing machine. In particular, the invention relates to a method for operating a washing machine comprising a tub for holding water, a drum rotatably mounted in the tub for holding laundry, a heating element for heating the water, a circulation system for conveying the water from a first area of the tub to a second area of the tub, and a control and/or regulating device for controlling and/or regulating a washing program, comprising a heating process during the execution of a washing program, and a correspondingly designed washing machine. The primary goal of the heating process in a washing machine is the most efficient possible transfer of heat energy between the heating element and the laundry, while simultaneously minimizing water consumption and operating cycles. This energy transfer occurs via heated free liquor. It is optimal when there is a continuous exchange between the concentrated and heated free liquor. Depending on the washing machine model, particularly whether it has or does not have a water bath, and the required heating temperatures, two different methods are currently in use. In the classic method, heat energy transfer between the heated and concentrated liquor is achieved through high water levels. The liquor exchange occurs via the absorbency of the laundry. This method is generally used in washing machines without a water bath. In washing machines with unregulated recirculation, the water exchange occurs when the recirculation system is activated. The heated, free-flowing water is introduced into the laundry via the recirculation system. The water level drops very quickly because the recirculation system's pump operates at a high flow rate, which cannot be varied. This, in turn, greatly increases the risk of overheating due to the rapidly changing water levels. While it's possible to correct the water level by continuously adding water, this results in high overall water consumption. Therefore, the heating element and recirculation system are always switched on and off sequentially. However, this leads to frequent switching cycles and a longer heating process, as the water levels must readjust each time. While the introduction of recirculation makes the heating process more efficient compared to traditional heating with high water levels, it does result in a longer cycle. The invention thus addresses the problem of providing a method for operating a washing machine and a washing machine whose heating process for heating free liquor can be carried out more time-efficiently using a recirculation system. According to the invention, this problem is solved by a method with the features of claim 1 and a washing machine with the features of claim 10. Advantageous embodiments and further developments of the invention are described in the following dependent claims. The advantages achievable with the invention lie in the fact that the heating process is significantly shortened by simultaneously heating and circulating the water and detergent. Ideally, each heating process can thus consist of only one heating cycle. This minimizes the stress on the components due to the reduced number of switching cycles. This applies to both the heating element and the circulating solution. In addition to the advantages already described, the time saved in heating results in further benefits during the program sequence. This time can be used to extend the washing process. Particularly at high temperatures, this leads to better washing results. Alternatively, a shorter program cycle can be achieved. Furthermore, the reduced stress on the components allows for design and component-related savings, which lower manufacturing costs. The invention relates to a method for operating a washing machine comprising a tub for holding water, a drum rotatably mounted in the tub for holding laundry, a heating element for heating the water, a circulation system for transferring water from a first section of the tub to a second section, and a control and/or regulating device for controlling and/or regulating a washing program. The method includes a heating process during the execution of a washing program, wherein the water level in the tub is controlled and/or regulated during the heating process such that the water in the tub is simultaneously heated by the heating element and transferred from the first section of the tub to the second section by means of the circulation system. Controlling and/or regulating the water level to a suitable level enables simultaneous heating with excellent water exchange. The water level is preferably above the heating element, relative to the washing machine's standard operating position. Preferably, the water level in the lye tank during the heating process is controlled and/or regulated by adjusting the flow rate of the circulating system and/or the rotation rate of the drum. Preferably, the water level is controlled and/