Method for operating a washing machine and washing machine

Abstract

The invention relates to a method for operating a washing machine with a tub for receiving washing liquid, a drum rotatably mounted in the tub for receiving laundry, and a receiving device for receiving and feeding detergent into the tub, wherein the method comprises: a) treating the detergent by exposure to an oxidizing agent, a temperature change, a water hardness change, and / or a pH change; b) feeding the treated detergent into the tub; and c) performing a washing step to wash the laundry with the supplied detergent.Furthermore, it relates to a washing machine with a tub for receiving washing liquid, a drum rotatably mounted in the tub for receiving laundry, a receiving device for receiving and feeding the detergent into the tub, and a control and / or regulating device configured to control and / or regulate the method according to one of the preceding claims.

Description

[0001] The invention relates to a method for operating a washing machine and a washing machine.

[0002] It is common knowledge that proteases damage wool and silk fibers. Wool and silk fibers consist of proteins, i.e., polypeptides, which, according to theory, are hydrolyzed and thus damaged by the proteases used in conventional detergents for protein stain removal. Therefore, there is no wool and silk detergent that contains proteases as an ingredient, nor is the bleaching agent hydrogen peroxide added to wool and silk detergents. However, proteases are the most frequently used enzymes, both qualitatively and quantitatively, in all conventional all-purpose and color detergents, in both liquid and solid form. For washing wool and silk, however, there is a separate, special detergent. A user of an automatic washing machine is therefore forced to buy a special wool and silk detergent if they want to wash wool or silk. This results in extra costs.In addition, he has to store the special detergent, which takes up space.

[0003] Furthermore, the following publications are mentioned in relation to the invention: WO 2021 / 105919 A1, DE 10 2019 201680 A1 and WO 2016 / 055321 A1.

[0004] The invention therefore addresses the problem of providing a method for operating a washing machine and a washing machine with which the user can wash wool and silk without needing a special detergent suitable for these materials, in particular a protease-free detergent.

[0005] 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 9. Advantageous embodiments and further developments of the invention are described in the following dependent claims.

[0006] The advantages achievable with the invention include not only considerable comfort and convenience for the user, but also the ability to save space and money by eliminating the need to store special detergents. One detergent can be used for all common applications. Furthermore, it contributes to environmental protection, as the user does not need to purchase separate wool and silk detergents.

[0007] The invention relates to a method for operating a washing machine with a tub for receiving washing liquid, a drum rotatably mounted in the tub for receiving laundry, and a receiving device for receiving and feeding protease-containing detergents into the tub, wherein the method comprises: a) Treating the protease-containing detergent by exposing it to an oxidizing agent, changing the temperature, changing the water hardness and / or changing the pH; b) Adding the treated protease-containing detergent to the washing container; and c) Performing a washing step to wash the laundry with the added detergent.

[0008] The invention is based on the idea of ​​actively influencing the activity of the proteases in the protease-containing detergent. Inactivation or at least a reduction of the activity is achieved by changing at least one relevant parameter, such as temperature, water hardness / ion concentration, or pH of the fluid to be treated, in particular the detergent concentrate or diluted detergent. The oxidizing agent is, for example, H₂O₂.

[0009] According to the invention, step a) is carried out when a selected and started washing program is a washing program designed for washing protease-sensitive materials.

[0010] Wool and / or silk are preferred materials that are sensitive to proteases. That is, the selected and started washing program is preferably a washing program suitable and / or intended for washing wool and / or silk. According to the invention, the activity of a protease contained in the detergent is reduced in step a) to at most 1 / 2, preferably 1 / 10. This reduction is sufficient to satisfactorily reduce or prevent damage to the wool and / or silk fibers.

[0011] The receiving device can be a detergent dispenser. Preferably, the receiving device is a dosing device designed to automatically dose the detergent into the washing machine tub. This prevents or at least reduces overdosing of the detergent.

[0012] In a preferred embodiment, step a) involves exposing the detergent to an oxidizing agent, an increase in temperature, a water-hardness-modifying agent, and / or a pH-modifying agent for a predetermined period. The detergent is supplied during the washing process, treated to a predetermined degree of inactivation, and then added to the lye tank. This further prevents or at least reduces damage to the wool and / or silk fibers.

[0013] Preferably, the predetermined time period depends on the concentration of the detergent and / or a temperature increase in step a). The higher the temperature in step a), the shorter the predetermined time period.

[0014] In a preferred embodiment, step a) involves exposing the detergent to an increase in temperature, preferably to a temperature of at least 40°C, for a predetermined period. Inactivation by temperature is relatively simple. By heating the detergent, preferably for a predetermined period which depends on the selected temperature and the concentrate used and / or its dilution, the proteases and any other detergent enzymes contained in the detergent are denatured. The increased temperature alters the three-dimensional structure of the enzyme, and its activity decreases or becomes undetectable. The protease-free detergent obtained after step a) can now be used as a wool and silk detergent without damaging the wool and / or silk fibers in step c).

[0015] The invention further relates to a washing machine with a tub for receiving washing liquid, a drum rotatably mounted in the tub for receiving laundry, a receiving device for receiving and feeding the protease-containing detergent into the tub, and a control and / or regulating device configured to control and / or regulate the method according to one or more of the embodiments described above.

[0016] The term "washing machine" includes both an automated washing machine and a combination appliance such as a washer-dryer.

[0017] The invention is described in more detail below in the accompanying drawing. It shows a schematic representation and is not to scale. Fig. 1 shows protease stability as a function of time and temperature.

[0018] Fig. 1This shows protease stability as a function of time and temperature. As can be seen, protease stability decreases with increasing temperature and time. In particular, at temperatures of 50°C or 60°C, protease stability drops relatively quickly.

Claims

1. Method for operating a washing machine comprising a suds container for receiving washing liquid, a drum rotatably mounted in the suds container for receiving laundry and a receiving means for receiving and feeding protease-containing detergent into the suds container, the method comprising: a) treating the protease-containing detergent by means of exposure to an oxidising agent, a temperature change, a water hardness change and / or a pH change; b) feeding the treated protease-containing detergent into the suds container; c) carrying out a washing step to wash the laundry using the fed detergent, the step a) being carried out when a selected and started washing programme is a washing programme which is designed for washing protease-sensitive materials; and characterised in that an activity of a protease contained in the detergent is reduced in the step a) to at most 1 / 2, preferably 1 / 10.

2. Method according to claim 1, characterised in that the protease-sensitive materials are wool and / or silk.

3. Method according to either of the preceding claims, characterised in that the receiving means is a dosing means which is designed to automatically dispense the detergent into the suds container.

4. Method according to any of the preceding claims, characterised in that the step a) comprises exposing the detergent to an oxidising agent, a temperature increase, a water-hardness-changing agent and / or a pH-changing agent for a predetermined period of time.

5. Method according to claim 4, characterised in that the predetermined period of time depends on a concentration of the detergent and / or on a temperature increase in the step a).

6. Method according to either of the preceding claims 4 or 5, characterised in that the step a) comprises exposing the detergent to the temperature increase, preferably to a temperature of at least 40°C, over the predetermined period of time.

7. Washing machine comprising a suds container for receiving washing liquid, a drum rotatably mounted in the suds container for receiving laundry and a receiving means for receiving and feeding the protease-containing detergent into the suds container, and a control and / or regulating apparatus which is configured and designed to control and / or to regulate the method according to any of the preceding claims.

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