RU2622811C2 - Water-using household appliance with internal surface to be cleaned and method of instrument maintenance - Google Patents

Abstract

FIELD: human vital needs satisfaction.

SUBSTANCE: invention relates to a water-using household appliance 1, 2 with a working chamber 3 intended to accommodate items 7 to be treated, with at least one inner surface 10, 11, 33, 40, 41 and in particular a supply conduit 8, 9 for water. The inner surface 10, 11, 33, 40, 41 comprises a coating 17 containing a switchable polymer. In addition, the invention relates to a method of operating such a household appliance.

EFFECT: improvement of the device durability and operation reliability.

10 cl, 2 dwg

Description

The invention relates to a water-consuming household appliance with an inner surface and to a method for its operation. In particular, the invention relates to a water-consuming household appliance having a working chamber for accommodating objects to be processed therein and at least one inner surface.

In water consuming household appliances, in particular washing machines, washing and drying machines, drying machines, in particular condensation drying machines, or dishwashers in the area of components with constantly wet surfaces, a biofilm is often formed. At the same time, “permanently wet surfaces” means surfaces that come into contact with water or water-containing liquids during normal operation of a household appliance. Biofilms are formed mainly in water supply systems in the border zones, for example, in zones of transition to the solid phase, and consist of a thin layer of mucus into which microorganisms are immersed. In order to protect themselves from external influences and improve their living conditions, microorganisms surround themselves with extracellular polymeric substances (ERW). ERW in combination with water forms hydrogels, resulting in a mucus-like matrix in which nutrients and other substances are dissolved.

As a result, a dark coating is often formed on the surfaces, accompanied by an unpleasant odor. Biofilms formed, for example, in a washable tray and in chambers for washing household appliances, can worsen the hygienic and aesthetic condition and / or cause an unpleasant odor. In addition, the hygienic condition of the accumulated water, which is stored in some household appliances for reuse in subsequent stages of the process, may be impaired if the total bacterial contamination of the water directly related to the thickness of the biofilm is too large. Finally, the metabolism of microorganisms in a biofilm can result not only in smell, but also in discoloration and corrosion.

Therefore, it is necessary to exclude as much as possible the formation of biofilms on the surfaces of water-consuming household appliances. In particular, it is necessary to deal with existing biofilms and, if possible, eliminate them. To this end, biocidal properties are imparted to the surfaces of household appliances at the prior art, in particular, this relates to a washing tray of a washing machine. However, surfaces with biocidal properties are not able to constantly prevent the formation of biofilms, since they destroy only those microorganisms that are in direct contact with the biocidal surface. Other microorganisms that settle on dead microorganisms can often survive and multiply.

On the other hand, biocidal chemicals acting on biofilms from the outside, as a rule, destroy only the upper layers of microorganisms. Deeper layers often remain unaffected since they are protected by ERW. In addition, the use of chemicals requires a high concentration of the active substance and long exposure. Finally, biocides and chemicals, as well as the products of their reactions, are often harmful to the environment and / or hazardous to health and can cause, for example, allergies. Another problem is that the reuse of biocides can lead to the development of resistance of microorganisms, which further complicates the fight against them.

Known processes of thermal suppression of vital activity do not eliminate the biofilm itself, as a result of which colonies of new microorganisms can develop on dead microorganisms or the remaining biofilm. However, they often find the ideal nutrient medium, which often contributes to the re-development of microorganisms.

In addition, biological processes for preventing the formation and / or elimination of biofilms are known. DE 3841596 A1 discloses a method for reducing the formation of mucus and deposits in water circulating systems. In this case, mobile microorganisms are added to the circulating water, which compete for the nutrient medium with the microorganisms that form the biofilm, and thereby reduce the formation of the biofilm.

EP 1 350 575 B1 discloses a surface with switchable ultra-hydrophobic properties and a method for its implementation. The surface is, in particular, a rough surface with switchable intrinsic wettability, moreover, as part of the switchover, a reversible transition to the combined surface is carried out in the sense of the Cassie-Baxter theory containing a substrate coated with a thin layer with switchable wettability. The intrinsic wettability is switched by changing the temperature, pH-value or electric fields, or by contact with selective solvents. The thin layer, preferably, consists of at least one hydrophilic component and one hydrophobic component, which are alternately concentrated on the surface by phase separation. For example, a thin layer can be made in the form of a multicomponent polymer brush, and phase separation can be realized for its components by contact with selective solvents.

Dresden» («Научный журнал Технического университета Дрездена»), том 56 (2007), №1-2, стр. 47-51.Brush-like polymers on switchable surfaces are described by Petra Uhlmann et al. In Wissenschaftliche Zeitschrift der Technischen

Dresden ”(“ Scientific journal of the Technical University of Dresden ”), Volume 56 (2007), No. 1-2, pp. 47-51.

Switchable polymeric surfactants are described in Fraunhofer IAP Jahresbericht 2003 (2003 Fraunhofer Institute for Applied Polymer Research Annual Report) on pages 66 and 67.

Switchable coatings with biocidal properties that counteract the formation of biofilms and are formed by functional block polymers and graft polymers of a particular architecture are described by Eva Maria Berndt et al. In Polymer Eur. Polym. J. ”(Journal of European Polymers), January 1, 2009, p. 1, see the Internet at https://www.uni-due.de/imperia/md/content/absolventenehrung/2012/2012_berndt_poster.pdf.

The article “From Self-Organizing and Switchable Polymers to Intelligent Materials” by Professor Andre Laschewsly dated 12/12/2002, available on the Internet at http://www.chem.uni-potsdam.de/apc/pdf/heft- beitrag_mit_bildern.pdf, in the “Switchable Polymers” section, mentions ongoing work on a combination of self-organizing and switchable polymers. At the same time, it is pointed out that the development of synthetic materials is a very difficult task, which scientists are still approaching and which may require completely new approaches. An example is a polymer poly- (tris-acrylamide) with a transition temperature, for example, 37 ° C.

EP 1916325 A1 discloses a method for removing biofilm in a household appliance (in particular, a washing machine) containing a structure defining a cleaning chamber, the biofilm adhering to the structure, the method comprising the following steps: heating the chamber to separate the biofilm from the structure in the absence of liquid in the chamber; and flushing the detached biofilm with liquid from the chamber. The properties of the surface on which the biofilm to be removed can form and grow are not considered. It is believed that heating the biofilm, possibly in interaction with a pesticide or other chemical substance, reduces the adhesion of the biofilm and disinfects the surface. For this, heating to 60 ° C and above is usually carried out, and a temperature of 70 ° C is particularly suitable for disinfection.

JP 2010-227834 A discloses a washing machine in which a functional layer is formed, characterized by minimal adhesive ability. The surface coated with the functional layer, in order to develop hydrophilicity, is brought into contact with water distributed over the surface in order to reduce the adhesion of the detergent foam or the like. The interior of the water tank dries quickly, as a result of which the multiplication of microorganisms is much more difficult.

Thus, the aim of the present invention is to develop a water-consuming household appliance, characterized by improved prevention of biofilm formation and improved fight against them. In particular, it is necessary to facilitate the removal of biofilms. In addition, the aim of the invention is to develop a method of operating such a household appliance. In the description of the present invention, the term "biofilm" is used for biofilm as such, as well as for more or less large clusters of microorganisms on the inner surface of a water-consuming household appliance that have not yet formed a biofilm.

The purpose of the invention is achieved thanks to a water-consuming household appliance and the method of its operation with the features disclosed in the respective independent claims. Preferred embodiments of the invention are disclosed in the respective dependent claims. Preferred variants of the method correspond to preferred embodiments of a household appliance and vice versa, even if not explicitly indicated.

Thus, the invention relates to a water-consuming household appliance with a working chamber designed to contain objects to be processed therein and at least one inner surface, the inner surface comprising a coating comprising a switchable polymer.

The term “coating” should be understood in a broad sense. It relates, inter alia, to more or less thin coatings of other materials, for example metals or other polymers. In addition, for example, a component of a household appliance containing such an inner surface may comprise or consist of a switchable polymer. Thus, “switchable polymer coating” in the broad sense means that at least one inner surface of the component has a coating that includes the switchable polymer. The coating may also include the presence on the inner surface of the polymer chains located more or less close to the inner surface, while at least one end of such polymer chains is attached to the surface. In this case, attachment can be understood as a chemical or physical compound.

The term “switchable polymer” in this case means that the polymer has at least two different states, and these states essentially differ in various internal or surface structures between which you can switch in a water-consuming household appliance. That is, a switching or switching operation can be performed in which the polymer transitions from the first state to the second state in which the biofilm adheres to the polymer worse than the first position. Preferably, this switching operation can be reversible, that is, according to the invention, polymers with reversible switching are preferably used.

In a preferred embodiment of the water-consuming household appliance, the switchable polymer structure can be switched by changing external chemical and / or physical conditions. In this case, under physical conditions we mean, in particular, temperature, pH, ionic strength and / or pressure. Chemical conditions include, in particular, one of the chemical reactions selected from the group consisting of protonation-deprotonation reactions, dissociation reactions, rearrangement reactions, and oxidation or reduction processes.

In the event that the switching process is initiated by a temperature change, for example by heating the switch polymer, it is possible, for example, to wash the inner surface containing the switch polymer, for example a wash tray, with plenty of warm water, for example wash liquid, or heat the heating wires immersed sufficiently into switchable polymer. In addition, you can combine both methods of switching the switchable polymer by changing the temperature. Heating with a warm wash liquid, in particular water or another water-containing liquid mixed with a detergent, is advantageous in that the biofilm, whose adhesion to the surface is weakened after the switching process, can be separated and eventually washed off under the mechanical influence of the current wash liquid.

Preferably, the surface structure of the switched polymers and thereby the surface property can be switched. The property may be, for example, the hydrophilicity of the inner surface, characterized by essentially more or less high wettability with an aqueous liquid and / or more or less large adhesion of microorganisms and thereby biofilms, or the size and / or roughness of the inner surface.

In addition, in some embodiments of the invention, in particular, the inner coating layer containing switchable polymers can be made so that the structure of the inner layer also changes during the switching process. In this embodiment of the invention, in particular, it is possible to introduce into the coating composition substances that differ in biocidal activity and are capable of quickly reaching the surface and, thus, the biofilm after the switching process. This could be an example of a controlled release process through the use of switchable polymers according to the invention.

According to the invention, the coating may be relatively thin. Preferably, the coating has a thickness of not more than 5 μm, in a particularly preferred embodiment, not more than 2 μm, and in the most preferred embodiment, not more than 1 μm.

According to the invention, a water consuming household appliance is not particularly limited. The invention relates to all water consuming household appliances in which biofilms can form in the presence of water, and in which it is desirable to prevent the formation of biofilms, reduce the formation of biofilms and / or eliminate biofilms, and a household appliance, in particular, may include a water supply line. In a particularly preferred embodiment of the invention, the water consuming household appliance is a dishwasher, washing machine, washer-dryer or dryer, in particular a condensation dryer. In this case, the condensation drying machine is a drying machine in which moisture is removed from the warm and moist process air coming from the drying chamber (working chamber) containing the wet laundry by the condensation method. Condensate is temporarily stored and / or removed from the dryer, so the dryer can also be considered a water consuming household appliance.

The claimed household appliance contains a working chamber intended for placement in it of objects to be processed, for example, linen or utensils. Therefore, the working chamber is often a drum. The term "processing" means, in particular, washing or drying the processed items.

In a particularly preferred embodiment, the inventive household appliance is a washing machine with a washing solution tank, a drum, a water supply system and a washing solution discharge system with a suction pump, as well as a control unit.

Preferably, a water-consuming household appliance is used comprising a storage tank for water used in a household appliance. In such a household appliance, the used water-containing liquid is stored or accumulated for reuse and, thus, is recycled. In a washing machine or a washer-dryer, for example, relatively clean water from the last rinse cycle is suitable. Such a water storage device may receive water from various sources and, depending on the sole or preferred source of water, may be, for example, a condensate collecting tank, a soft or hard water tank and / or a washing water tank. In a dishwasher, washing machine or washer-dryer, the water storage tank is preferably a rinse water tank. Used rinse water is usually temporarily stored in the rinse water tank for reuse, for example in a subsequent washing cycle. In the dryer or washer dryer, the water tank is preferably a tank for collecting condensate that accumulates during the drying of moist air, for example, a condensate tray located under the heat exchanger. In addition, the water storage device may also be a reservoir for soft or hard water, for example, if the washing machine is equipped with a demineralization device.

In the aforementioned water storage devices, the probability of the development of biofilms is high, as a result of which the performance of an inner surface coated with a switchable polymer will be very beneficial. In particular, this will allow you to comply with hygiene requirements when storing wash water for reuse in subsequent stages of the process.

In a further preferred embodiment, the water consuming household appliance comprises a control device configured to carry out a switching process, for example, automatically or at the command of a user.

According to the invention, there are no special requirements for the inner surface in a water-consuming household appliance, and it can be any inner surface inside such a household appliance, in particular, a surface made of plastic, metal, rubber, etc.

Preferably, the surface is a constantly wet inner surface. Moreover, by “constantly wet inner surface” is meant, in particular, the surface inside the household appliance, which in normal operation of the household appliance comes into contact with water or an aqueous liquid.

In a preferred embodiment, the constantly wet inner surface is a flushing tray, the inner wall of the washing solution tank, a water tank, a water passage, a heat exchanger surface and / or a condensate tray. Moreover, by the inner wall of the washing solution tank is meant, preferably, the rear region of the drum support, which is most prone to the formation of biofilms.

The switching process in the sense of the invention can have a different duration, and the duration of the switching process in the sense of the present description includes not only the duration of the switching process itself between the two states of the switched polymer, but also, essentially, the time of maintaining the second state.

Switchable polymers used in accordance with the invention have no restrictions, except for the need to implement a switching operation in a water-consuming household appliance, resulting in poor adhesion of the biofilm to the surface. In this case, the chemical composition of the switched polymer depends, in particular, on the type of initialization of the switching process, that is, in particular, on the type of change in external physical or chemical conditions.

Thus, switched polymers can be used, for example, polymers with internal conductivity, for example unsubstituted or substituted polythiophenes, polypyrroles and / or aromatic polyvinyl compounds. In addition, surface-active polymers, metallic colloids, partially acylated poly-tris-acrylamide, poly- (styrene sulfonate) -block-poly- (acrylamide) or the so-called “polymer brushes” are particularly suitable.

So, the switched polymer can be, for example, a polymer brush, consisting of at least two significantly different polymers, one end of the chain of which is attached to the material of the component of the household appliance. Depending on the external conditions, these different polymers can alternately concentrate on the surface, as a result of which the surface properties are determined in each case by one or another polymer. Between these states can be switched. A method for producing such polymers is described, for example, in S. Minko, S. (hrsg.): Responsive Polymer Materials. Ames: Blackwell Publ., 2006.

In a preferred embodiment, the coating thus consists of, or comprises, polymer chains of at least two different polymers grafted to the surface. Essentially, they are incompatible, resulting in the separation or spatial separation of these polymer chains.

Alternatively or in addition, different polymers may be on the same surface, the polymer chains not substantially protruding above the surface.

The present invention also relates to a method of operating a water-consuming household appliance with a water supply line and a working chamber designed to accommodate objects to be treated therein, as well as with at least one inner surface, the inner surface comprising a coating comprising a switchable polymer, moreover, the method comprises step (a) changing the physical and / or chemical external conditions, as a result of which the state or structure of the polymer passes from the first state to the second standing or from the first structure to the second structure, characterized by poor adhesion of the biofilm to the polymer compared with the first structure.

Preferably, in the inventive method, switching between the first and second structure and vice versa is carried out often enough and / or long enough so that the surface properties of the switched polymer, due to changes in external physical and / or chemical conditions, are changed to an extent sufficient to break the bond with the biofilm.

In addition, it is preferable that the change in physical and / or chemical conditions is a change in temperature or pH.

The claimed method can be carried out at various points in time, for example, as a procedure that is not part of the processing process in a water-consuming household appliance. In a preferred embodiment of the method, the switching process is carried out at a time when the program for processing items to be processed and placed in the working chamber is executed in a water-consuming household appliance.

So, for example, the inner wall of the tank for washing solution in the area of the bearing support, the most prone to the formation of biofilms, heats up when the drum moves. In particular, heating is very pronounced during centrifugation. Thus, in particular, switchable polymer switching can be initiated during the centrifugation step. In the next rinse, the biofilm, whose adhesion to the surface is weakened, can be disconnected and removed together with the washing liquid.

Thus, for example, in a washing machine, taken as an example of the claimed water-consuming household appliance, it becomes possible to implement the method described by the invention as a cleaning program, both within the washing cycle, in particular, during the centrifugation steps included in it, and as part of a separate cleaning programs. At the same time, a separate cleaning program is carried out, in particular, after the completion of the washing program, that is, when the laundry in the working chamber is removed.

In a preferred embodiment of the inventive method, the drum of the washing machine rotates at a high frequency when the water level is preferably elevated. This allows you to effectively remove the biofilm present, in particular, in the rear of the tank for washing solution.

In embodiments of the invention in which the household appliance is a dryer or washer-dryer with a heat exchanger for moist and warm process air, the biofilm grows, in particular, on the heat exchanger. On the other hand, during the drying process, the temperature of the heat exchanger can rise to a degree sufficient to initiate the switching process and, therefore, deterioration of the adhesion of the biofilm. Even if the temperature decreases again when the refrigerant passes through the heat exchanger and thereby the initial state is restored due to the switching process, the adhesion of the biofilm can be deteriorated so that it can be washed off with condensate, which subsequently settles on the heat exchanger.

The next way to initiate the switching process is to change the pH value, for example, from neutral to alkaline. In a switched polymer, this can occur, for example, under the action of an alkaline solution, for example, a washing solution. This switching process can also be carried out during the execution of the washing program, for example, if, for example, an alkaline detergent is used in the washing program. In this case, essentially, the exposure time of the alkaline solution is controlled by a timer or a sensor so that the alkali can pass through the biofilm formed and achieve a switchable coating. The biofilm formed during the downtime of the washing machine, taken as an example of the claimed water consuming household appliance, will be removed during the next wash program.

Finally, switching the switched polymer can also be accomplished by changing the ionic strength of the solution or the aqueous liquid in contact with the switched polymer. The ionic strength of the solution can be increased, for example, by adding salts.

Thus, a change in ionic strength, particularly preferably, can be performed in such water consuming household appliances in which a solution of high ionic strength can be easily obtained. In particular, these are dishwashers that use a regenerating solution of a water softener, as well as washing machines and washer-dryers with a device for demineralizing the water used. In such washing and washing-drying machines, there is usually not only demineralized water, but also, as a rule, a solution with a high concentration of salt.

In this case, it is also essentially advisable to set the minimum contact time with the solution used for switching, so that a sufficient degree of reduction in the adhesion of the biofilm can be guaranteed. In such an embodiment, the relationship between the minimum contact time and the size and type of biofilm can be recorded in the control device of the household appliance, that is, the minimum contact time can be adjusted depending on the detected biofilm.

Depending on the nature of the inner surface or the method of initiating the switching process, it may be desirable to change the external chemical and / or physical conditions so that the aqueous liquid, essentially the solution, after coming into contact with the inner surface, essentially no longer moves ("static contact"). Alternatively, dynamic contact can be achieved by continuously or periodically passing the solution along a switched inner surface.

In addition, the switching process may be due to a chemical reaction occurring on the inner surface. Depending on the oxidizing or reducing potential of the switchable polymer, for example, an oxidation or reduction process (hereinafter referred to as the “redox reaction”) can be carried out. In this case, the change in the structure of the switched polymer caused by the switching process consists in the difference between the oxidized / reduced and neutral forms, in particular, in the difference in properties leading to a decrease in the adhesion of the biofilm. Such a redox reaction can be realized, for example, by bringing into contact with the surface to be cleaned an oxidizing agent, for example, ozone, gaseous or dissolved in water, or hypochlorite. Thus, the biofilm can be separated, on the one hand, by chemical action on the biofilm as such, and on the other hand, by initiating the switching of the switched polymer using an oxidizing agent.

The redox reaction may be particularly preferred also if the surface contains polymers having electrical conductivity. Suitable electrically conductive polymers are obtained, for example, from substituted or unsubstituted polythiophenes, polypyrroles, polyphenylenes and aromatic polyvinyl compounds. In this case, the state of oxidation of the polymer can be changed electrically or chemically, and different degrees of oxidation differ essentially in their structure and electrical conductivity. As a rule, electrically conductive polymers in the oxidized state contain the most conjugated system of chemical bonds.

To carry out such a redox reaction with electrically conductive polymers, for example, one of the aforementioned chemical oxidizing agents, for example, ozone or hypochlorite, can be used. As an alternative or addition, electrically conductive polymers can also be connected to a power source, that is, their structural and electrical properties can be purposefully changed by changing the applied electrical voltage. Thus, it is possible to separate the biofilm, directly or indirectly, optionally, using other polymers adjacent to the electrically conductive polymer.

If the electrical conductivity of the surface is due to a material whose structure does not change when an electrical voltage is applied, for example, metal or graphite, then the biofilm can be oxidized by applying a sufficiently high oxidation potential. In addition, the application of a sufficiently high oxidation potential allows the production of chemical compounds, which subsequently, possibly, will be present as a layer and cause the polymer to switch, switched by redox reactions.

The claimed method can be launched in various ways, in particular, automatically or at the command of a user of a water-consuming household appliance. In this case, the automatic implementation of the method described by the invention can be controlled by a timer or a sensor.

Therefore, in a preferred embodiment of the inventive method, the switching provided by the invention, which is preferably followed by additional washing with a washing agent, occurs when the sensor indicates the presence of a biofilm on the inner surface.

Such a sensor may be, for example, an odor sensor or an optical sensor. For example, the claimed method can be initiated when the sensor signal reaches or exceeds a predetermined predetermined odor value or optical characteristic, for example, scattering or absorption. The sensor may also be a turbidity sensor or a sensor for determining refractive index, surface tension or electric capacitance. Corresponding sensors can be located, for example, in those areas of a water-consuming household appliance that are most prone to biofilm formation.

Preferably, the control device of the water-consuming household appliance is configured to implement the inventive method so that it can determine the presence or risk of biofilm formation based on the data received from the sensor. For this, the control device can essentially receive signals from the sensor, which are subsequently compared with the data stored in the memory of the control device, which makes it possible to determine the presence of a biofilm or the danger of its formation. Then, based on the obtained results, the switching process of the switchable polymer provided for by the invention is initiated.

As an alternative or addition, the claimed method or the processing provided therein is preferably implemented after reaching or exceeding the specified operating time of the household appliance.

Therefore, in the following embodiment, the claimed method is initiated in time. In this case, the polymer switching process occurs at a time specified by the program. The initiation of the process will depend, in particular, on how polymer switching can be carried out. For example, the method can be started by raising the temperature when a certain minimum temperature value (“switching temperature”) is reached in each washing or rinsing cycle using an aqueous liquid of a sufficiently high temperature. If the switching is initiated by changing the pH value, then the switching process can be started by changing the pH value by a sufficiently large amount.

In addition, after prolonged downtime or with frequent use of washing or rinsing cycles, the biofilm processing step can be automatically performed at regular intervals.

In a preferred alternative embodiment of the invention, the user of the water consuming household appliance manually starts the claimed method. So, for example, the method described by the invention can be performed before a planned long downtime of a household appliance in order to eliminate biofilms. In this case, the switching process initiated by the user is preferably carried out in conjunction with the corresponding washing process, which in the washing machine is preferably, for example, draining the liquid through the washing tray, draining the washing liquid from a special chamber or discharging the liquid from the washing liquid reservoir .

In addition, the initiation of the user-provided processing by the invention can be combined with corresponding sensors, for example, by informing the user by means of optical or acoustic indicators of the presence or risk of biofilm formation. This can be implemented, as indicated in connection with the control by sensors, by means of the respective sensors and a suitably configured control program. However, in this embodiment, the method described by the invention does not start automatically, but prompts the user to issue a command to start the method, so that the user can start the process manually, if desired.

When the control program determines, based on the sensor signals, the presence or risk of biofilm formation, it can preferably bring this information to the attention of the user. This is realized, for example, using an indicating device with optical and / or acoustic signals.

The claimed method can be implemented in water-consuming household appliances, in particular dishwashers, washing, washing-drying or drying machines during normal program execution, in particular during rinsing, washing and / or drying. In this case, a separate “cleaning process” is not needed. However, the inventive method can also be implemented as a separate subprogram as part of the usual program of rinsing, washing and / or drying, or as a completely separate processing program.

In particular, it is preferable that the treatment, or in the case of an already formed biofilm, the step of removing the biofilm is carried out before and / or after prolonged shutdown of the household appliance. During long downtimes, in particular, the formation of biofilms is possible, which can be prevented and / or which can be eliminated by the claimed method. In a particularly preferred embodiment, the claimed method is implemented before a long downtime of a household appliance, since this helps to prevent the formation of biofilms and the occurrence of unpleasant odors, corrosion, etc.

The method described by the invention provides for the separation and removal (preferably disposal) of the detached biofilm from the surface, preferably with a washing liquid. In this case, as a washing liquid, you can use water as such or an aqueous liquid, which includes additives. These additives may be, for example, detergents or oxidizing agents.

The washing liquid can be introduced into a water-consuming household appliance in various ways, essentially depending on the type of household appliance and the internal surface with adhered biofilm. So, the washing liquid can enter the washing machine in the same way, that is, in particular, through the same pipelines as the liquid used to process objects.

In an alternative embodiment of the inventive method, the surface is irrigated with washing liquid using a suitable spray device. Therefore, in a preferred embodiment of the invention, the water consuming household appliance also comprises a spray device for washing liquid.

Finally, the inventive household appliance preferably comprises a reservoir for the flushing fluid already considered. In some embodiments, the flushing fluid is supplied at the command of the control device of the household appliance.

Thus, microorganisms and, in particular, biofilms, the adhesion of which was deteriorated by switching the switched polymer, are separated and removed mechanically. Such surfaces are, for example, in the area of a washable tray and a washing solution tank in a washing or washing-drying machine. Since these areas are most prone to biofilm formation, a variant in which a decrease in adhesion is supplemented by a subsequent washing step that has a mechanical effect is particularly preferred.

In addition, a variant is preferred in which the switching process due to the invention is associated with other chemical or mechanical cleaning steps. In this case, the mechanical cleaning step can be understood as brushing. For example, the use of an oxidizing agent, in particular ozone or hypochlorite, for example sodium hypochlorite, even if it is not used for the switching process, can accelerate the removal of biofilms. This processing step can be carried out before switching, simultaneously with it or after it. Preferably, after switching and the chemical or mechanical cleaning step, the washing step is carried out with a washing liquid to remove to a greater or lesser extent the separated biofilm or microorganisms from the inner surface and, preferably, from a water-consuming household appliance.

A household appliance and method according to the invention have several advantages. In particular, they prevent biofilm formation, reduce biofilm formation and / or eliminate biofilm on the surface of a water-consuming household appliance.

When applying the invention, the adhesion of the biofilm is essentially reduced, which makes it easy to remove it, for example, by washing with water or other washing liquid, and not only destroy it, as provided for by conventional methods. In addition, biofilms can be controlled without the formation of harmful decomposition products.

The claimed method allows you to process those areas of the household appliance according to the invention, which do not come into direct contact with the washing solution, but remain wet after the implementation of previous processes. Thus, a very thorough “cleaning” can be carried out.

Coating surfaces prone to biofilm formation with switchable polymers improves and facilitates the removal of biofilms formed. For example, when coated with amphiphilic switchable polymers, the surface structure can be switched so that a transition is made from a hydrophobic to a hydrophilic surface and vice versa. As a result, the adhesion of the biofilm can be impaired, that is, the biofilm in any case, after switching, will lose its adhesive properties. Subsequently, the no longer retained biofilm can be washed away, for example, with washing liquid, for example water. After that, the polymer can be switched back. This switching can preferably be done repeatedly (back and forth).

The following is a description of the invention with reference to exemplary embodiments shown in FIG. 1 and 2.

FIG. 1 is a schematic representation of components important for understanding the invention of the first embodiment of the water-consuming household appliance described by the invention, which in this case is in the form of a washing machine.

FIG. 2 is a vertical section through a water-consuming household appliance, which, in accordance with a second embodiment of the present invention, is designed as a drying machine in which heat recovery is carried out using an air-to-air heat exchanger.

The washing machine 1 shown in FIG. 1, comprises a washing solution tank 4, in which a drum 3, which acts as a working chamber for processing laundry 7, taken as an example of processed items, is mounted to rotate around a substantially horizontal axis 35 of rotation of the drum 3 and can be rotated drive motor 14. The long arrow indicates the direction of rotation of the drum 3. The laundry shifters 36 and scoops 37 on the inner surface of the drum shell enhance the impregnation of the washing solution 6.

The washing machine 1 contains a water supply line (also called a washing solution supply system), which includes fittings for connecting to a household water supply system 8, an electrically controlled valve 9 and a supply pipe 10 to the washing solution tank 4 passing through the washing tray 11 , from which incoming water can transport portions of detergent to the tank 4 for washing solution. A siphon 21 is integrated in the water supply line 10.

The washable tray 11 and the circulating water tank 33, which are the inner surface in the sense of the present invention, comprise a switchable polymer coating 17, which in this case can be switched by changing the temperature as part of changing external physical conditions.

A first embodiment of a water consuming household appliance according to the invention shown in FIG. 1, due to the presence of switchable polymers, it is possible to carry out the method according to the invention. As a result of a more or less long switching process, the adhesion of the biofilm to the inner surface decreases. This process can be supported mechanically and / or chemically through the use of washing liquid, and the use of washing liquid allows you to remove the separated biofilm.

For this, as shown in FIG. 1, the washing fluid reservoir 25 is connected by a water supply pipe 16 to an electrically controlled valve 9, which connects to a domestic water supply system 8. Thus, by introducing water, it is possible to dilute or replenish the wash liquid in the wash water tank 25.

In the washing machine 1 shown in FIG. 1, the washing liquid tank 25 is connected by the first washing liquid supply pipe 20 to the washing tray 11. In addition, a second pipe 26 for supplying the washing liquid to the washing solution tank 4 and a drum 3 which allows introducing flushing fluid through the cuff 24, only indicated in figure 1 and located in the boot hole 23 of the drum 3.

Finally, the washing machine 1 shown in FIG. 1, has additional features for using flushing fluid. To this end, a supply pipe 18 branches off from the washing liquid tank 25, leading to a spray device 31 and a water storage 33. In the supply pipe 18 is an adjustable locking device 28 that allows you to control the flow of flushing fluid. The household appliance according to the invention can also be equipped with other locking devices.

Through a spray device 31 located at the rear outlet of the washing solution tank 4, the washing liquid can be sprayed, for example, into the back of the washing solution tank 4, opposite the loading opening 23 and not shown in detail in the drawing. The inner wall of the tank for washing solution and, in particular, its rear part, opposite the loading hole 23, are constantly wet surfaces, the most prone to the formation of biofilms.

Finally, a flushing liquid can be supplied to the water tank 33 after the switching process in order to clean the water tank 33 from harmful microorganisms and possibly biofilms and thus increase the shelf life of the stored water under hygienic conditions. In FIG. 1, the connection of the water storage device 33 to the washing solution tank 4 is not shown in detail in order to increase visibility.

For acoustic and / or optical indication of the progress of the process described by the invention, a display device 29 is located on the washing machine in the embodiment shown here.

In the first embodiment shown in FIG. 1, the sensor 5 is located in the washable tray 11. The sensor 5 is, for example, an odor sensor or an optical sensor that is capable of detecting microorganism clusters or even biofilm. The sensor 5 is connected to the control device 12 of the washing machine 1 and can automatically initiate the implementation of the method described by the invention when a predetermined sensor signal is reached or exceeded.

In addition, in the washing solution tank 4 according to this embodiment, there is a heating device 13, a pump 22 for pumping water-containing liquid from the washing solution tank 4, and a sensor 15 for measuring the concentration of detergent and / or auxiliary detergents. These components, as well as the valve 9, the drive motor 14, the adjustable locking device 28 and the sensor 5 are connected to the control device 12, which can control the washing machine 1 in accordance with an algorithm that can be associated with a time control program and / or with the achievement known measured values of the parameters, in particular the level of the washing solution, the temperature of the washing solution, the rotational speed of the drum, determining the presence of microorganisms or biofilms, the concentration of detergent and / or auxiliary detergents, etc. in the washing machine 1.

In FIG. 2 is a vertical sectional view of a water consuming household appliance which, in accordance with a second embodiment of the present invention, is configured as a dryer 2, in which heat recovery is carried out using an air-to-air heat exchanger 40. The drying machine 2 comprises a drum 3 mounted rotatably around a horizontal axis and designed to accommodate laundry, not shown in the drawing, in particular, to be dried therein, and laundry shifters 36 are fixed inside the drum for moving laundry during rotation of the drum. The process air is directed by the blower 19 through the heating device 13 and the drum 3 into the supply duct 38. In the supply duct 38, ambient air is drawn in by the blower device 19 from the inlet 39 of the duct. The air heated by the heating device 13 is supplied to the drum 3 from the rear side of the drum 3, that is, from the side opposite to the door 42 of the dryer, through the perforated bottom, comes into contact with the laundry to be dried, and passes through the loading opening of the drum 3 to a lint filter 43 mounted inside the door 42 of the tumble dryer covering the feed opening. After passing through the drum 3, the flow of process air is deflected down the door 42 of the dryer. Wet and warm process air enters the outlet channel 33, in which there is an air-to-air heat exchanger 40, which cools the warm and moist process air (in this case, the exhaust air) and, after condensation of the moisture contained therein, directs air to the outlet 27 The separated moisture is collected in a condensate tray 41, from where it can be removed, for example by pumping.

For cooling, the air-to-air heat exchanger 40 uses ambient air entering the dryer 2 through the supply duct 38. This incoming air is heated by warm and moist process air, and then before being fed to the drum 3 by an additional heating device 13.

In the second embodiment shown in FIG. 2, the condensate tray 41 and the air-to-air heat exchanger 40 comprise a coating 17 as an inner surface in the sense of the invention, which includes a temperature-switchable polymer. In addition, there is provided a reservoir 25 for flushing fluid, allowing you to separate and remove the disconnected biofilm. For reasons of clarity, the supply of water to the washing liquid reservoir 25 is not shown in detail. The flushing fluid reservoir 25 is connected by a third flushing fluid supply pipe 30 to an air-to-air heat exchanger 40 and, ultimately, to a condensate tray 41. A biofilm sensor 5 is provided, whereby the method according to the invention can be initiated by analyzing the sensor signal.

The drum 3 in the embodiment shown in FIG. 2 is supported on the rear wall by means of a hinge support, and on the front wall by means of the bearing shield 44, the drum 3 being abutted by the rim to the sliding strip 45 on the bearing shield 44 and thereby being held at the front end. The condensation dryer is controlled by a control device 12, commands to which the user can issue via the control panel 34.

For acoustic and / or optical indication of the process described by the invention, an indication device 29 is located on the dryer.

LIST OF REFERENCE NUMBERS

one Washer 2 tumble dryer 3 working chamber, drum four washing solution tank 5 biofilm sensor (a), e.g. odor sensor, optical sensor 6 washing solution 7 linen 8 domestic water supply system 9 electrically operated valve 10 the supply line to the tank for washing solution eleven washable tray 12 control device 13 heating device fourteen drive motor fifteen sensor for determining the properties of an aqueous fluid 16 water supply line leading to the washing liquid tank 17 switchable polymer coating eighteen a supply line for flushing fluid, for example water, leading to a spray device and a water reservoir 19 blower twenty first flushing fluid supply line leading to the flushing tray 21 siphon 22 pump 23 loading hole 24 cuff 25 flushing tank 26 a second inlet pipe for washing liquid leading to the tank for washing solution / drum for linen 27 process air discharge; exhaust air outlet 28 adjustable locking device 29th indicating device thirty third flushing fluid inlet line leading to a heat exchanger and condensate pan 31 flushing fluid spray device 32 rear outlet for washing solution 33 storage tank for water (recycled water) 34 control Panel 35 axis of rotation 36 linen transfer 37 scoop device 38 supply channel 39 duct inlet 40 air-to-air heat exchanger 41 condensate pan 42 tumble dryer door 43 filter for villi 44 bearing shield 45 slip strip

Claims (11)

1. A water-consuming household appliance (1, 2), containing a working chamber (3), intended for placement in it of objects to be processed (7), at least one inner surface (10, 11, 33, 40, 41) and, in in particular, a water supply pipe (8, 9), characterized in that the inner surface (10, 11, 33, 40, 41) has a coating (17) with a switchable polymer, while the inner surface (10, 11, 33, 40 , 41) is a constantly wet inner surface, and the structure of the switched polymer has the ability to switch by changing the external physical physical conditions, and the physical conditions include temperature, which makes it possible to carry out a switching or switching process with the polymer moving from the first state to the second state, characterized by poor adhesion of the biofilm to the polymer compared to the first state, and the change in physical conditions consists in a temperature and the switching process is initiated by heating with an aqueous wash liquid. 2. A household appliance (1, 2) according to claim 1, characterized in that it is possible to switch the surface structure and, thus, the properties of the inner surface (10, 11, 33, 40, 41). 3. A household appliance (1, 2) according to claim 2, characterized in that the property is the hydrophilic properties of the inner surface (10, 11, 33, 40, 41). 4. A household appliance (1, 2) according to any one of paragraphs. 1-3, characterized in that the coating (17) has a thickness of not more than 5 microns. 5. A household appliance (1, 2) according to any one of paragraphs. 1-3, characterized in that the coating (17) includes a polymer from the group comprising metallic colloids and / or partially acylated poly-tris-acrylamides. 6. A household appliance (1, 2) according to any one of paragraphs. 1-3, characterized in that the coating (17) consists of polymer chains of at least two different incompatible polymers grafted to the surface, or contains such polymer chains. 7. A household appliance (1, 2) according to any one of paragraphs. 1-3, characterized in that the constantly wet inner surface is a flushing tray (11), the inner wall of the tank for washing solution, a drive (33) for water, a water channel (10), the surface of the heat exchanger (40) and / or tray ( 41) for condensate. 8. The method of operation of a water-consuming household appliance (1, 2), containing a working chamber (3), designed to place in it the objects to be processed (7), at least one inner surface (10, 11, 33, 40, 41) and in particular, a supply pipe (8, 9) for water, the inner surface (10, 11, 33, 40, 41) having a coating (17) with a switchable polymer, the inner surface (10, 11, 33, 40, 41) is a constantly wet inner surface, and the structure of the switched polymer has the ability to switch by changing the external phe- conditions, the physical conditions include a temperature that permits the implementation of switching or shifting process in which a polymer transitions from a first state to a second state characterized deteriorated adhesion of the biofilm to the polymer compared with the first state, moreover, the method comprises the step of changing the external physical condition affecting the switchable polymer, and changing the external condition causes the polymer to switch from the first state to the second state, characterized by poor adhesion of the biofilm to the polymer compared to the first state, and the change in physical conditions consists in changing temperature, and the switching process is initiated by heating with an aqueous wash liquid. 9. The method according to p. 8, characterized in that the switching between the first and second state and vice versa is carried out quite often and / or for a sufficiently long period of time so that the surface properties of the switched polymer due to changes in external physical and / or chemical conditions are sufficiently changed to break the connection with the biofilm. 10. The method according to p. 8 or 9, characterized in that the switching process is carried out during execution in a water-consuming household appliance (1, 2) of the program for processing objects (7) to be processed in the working chamber (3).

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