Classifications

• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47L—DOMESTIC WASHING OR CLEANING; SUCTION CLEANERS IN GENERAL
  • A47L15/00—Washing or rinsing machines for crockery or tableware
• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47L—DOMESTIC WASHING OR CLEANING; SUCTION CLEANERS IN GENERAL
  • A47L15/00—Washing or rinsing machines for crockery or tableware
  • A47L15/0002—Washing processes, i.e. machine working principles characterised by phases or operational steps
• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47L—DOMESTIC WASHING OR CLEANING; SUCTION CLEANERS IN GENERAL
  • A47L15/00—Washing or rinsing machines for crockery or tableware
  • A47L15/0018—Controlling processes, i.e. processes to control the operation of the machine characterised by the purpose or target of the control
• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47L—DOMESTIC WASHING OR CLEANING; SUCTION CLEANERS IN GENERAL
  • A47L15/00—Washing or rinsing machines for crockery or tableware
  • A47L15/0018—Controlling processes, i.e. processes to control the operation of the machine characterised by the purpose or target of the control
  • A47L15/0052—Noise reduction
• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47L—DOMESTIC WASHING OR CLEANING; SUCTION CLEANERS IN GENERAL
  • A47L15/00—Washing or rinsing machines for crockery or tableware
  • A47L15/42—Details
• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47L—DOMESTIC WASHING OR CLEANING; SUCTION CLEANERS IN GENERAL
  • A47L15/00—Washing or rinsing machines for crockery or tableware
  • A47L15/42—Details
  • A47L15/46—Devices for the automatic control of the different phases of cleaning ; Controlling devices
• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47L—DOMESTIC WASHING OR CLEANING; SUCTION CLEANERS IN GENERAL
  • A47L15/00—Washing or rinsing machines for crockery or tableware
  • A47L15/42—Details
  • A47L15/4214—Water supply, recirculation or discharge arrangements; Devices therefor
  • A47L15/4225—Arrangements or adaption of recirculation or discharge pumps
• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47L—DOMESTIC WASHING OR CLEANING; SUCTION CLEANERS IN GENERAL
  • A47L2301/00—Manual input in controlling methods of washing or rinsing machines for crockery or tableware, i.e. information entered by a user
  • A47L2301/04—Operation mode, e.g. delicate washing, economy washing, reduced time, sterilizing, water softener regenerating, odor eliminating or service
• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47L—DOMESTIC WASHING OR CLEANING; SUCTION CLEANERS IN GENERAL
  • A47L2501/00—Output in controlling method of washing or rinsing machines for crockery or tableware, i.e. quantities or components controlled, or actions performed by the controlling device executing the controlling method
  • A47L2501/05—Drain or recirculation pump, e.g. regulation of the pump rotational speed or flow direction
• • A—HUMAN NECESSITIES
  • A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
  • A47L—DOMESTIC WASHING OR CLEANING; SUCTION CLEANERS IN GENERAL
  • A47L2601/00—Washing methods characterised by the use of a particular treatment
  • A47L2601/02—Pressurised cleaning liquid delivered by a pump

Definitions

• the present invention relates to a method for operating a dishwasher comprising a washing tub for accommodating articles to be cleaned and a circulation pump for circulating a cleaning liquid within the washing tub, and wherein there is provided for a plurality of washing programs selectable by the user, said washing programs comprising a series of consecutive steps selected from water intake, pre-washing, washing, rinsing, soaking, draining and drying steps.
• a typical selection of washing programs in a dishwasher comprises a standard program carried-out at a washing temperature of for example 65 °C, an energy saving program in which the washing step is carried-out at a lower temperature of for example 50 0 C, an intensive washing program in which the washing step is carried out at a higher temperature of for example 70 0 C, and a quick cycle as it particularly can be used for cleaning glasses in which a shorter washing cycle is used and which is carried out at for example 40 0 C.
• the individual operation parameters such as the amount of water fed into the dishwasher and the duration of the individual steps can be fixed.
• the dishwasher may comprise an automatic mode wherein a washing program is automatically selected based on certain parameters which are detected by sensors provided in the dishwasher, such as the washing load (i.e. the amount and type of articles to be cleaned) and the amount of soiling.
• the present invention aims at providing a method for operating a dishwasher, by which the generation of noise during operation of the dishwasher is reduced.
• the noise level during operation as it is caused by the cleaning fluid circulated through the machine and by the operation of the circulation pump has been reduced by means of acoustic insulation to a level which is below the regular noise level experienced in a domestic household
• conventional dishwashers typically operate at a sound pressure level of 39 to 40 dB.
• washing program further comprises a first washing program in which the circulation pump is operated at a nominal speed, and a second washing program in which, for at least part of the program, the circulation pump is operated at a speed which is reduced with respect to the nominal speed, and in which there is provided at least one soaking step during which the circulation pump is inactive.
• nominal speed of the circulation pump denotes the speed at which the circulation pump is operated during regular operation of the dishwasher, i.e. during standard washing programs as they are known as such in the art and in which the speed of the circulation pump is selected primarily based on the amount and pressure of cleaning liquid as required to achieve a satisfactory cleaning result.
• nominal speed In dishwashers in which during all the regular washing programs the circulation pump is operated at a single speed, the term “nominal speed” thus denotes such single standard speed.
• the term "nominal speed” denotes any one of such standard speeds which, as was the case for a single speed pump, likewise are selected primarily based on the amount and pressure of cleaning liquid required to achieve a desired cleaning result.
• the present invention is based on the concept of actually lowering the speed of the circulation pump, which in conventional dishwashers is operated at a single speed and hence is subject to an on/off-control only. Since the reduction in operational speed of the circulation pump necessarily results in a decrease in cleaning efficiency, measures have to be taken to compensate for such decrease in cleaning efficiency.
• the reduction in operational speed of the circulation pump is made possible by including in the program sequence at least one soaking step, i.e. a step during which the articles to be cleaned within the dishwasher are first wetted with cleaning liquid, whereupon operation of the dishwasher is paused, i.e.
• the circulation pump is turned off for a certain period of time and the washing liquid is allowed to soak into the soiling that shall be removed from the articles to be cleaned.
• the present invention provides for an operation mode for a dishwasher in which the peak noise level experienced during operation of the dishwasher is lowered.
• the present invention thus provides for a true "silent mode" in which not only the sound level but also the sound pressure created by the dishwasher is reduced. Measurements have shown that by using the method suggested herein the operational noise of the dishwasher could be reduced by about 2 to 3 dB. Thus, using the method suggested herein dishwashers can be operated at noise levels of about 36 to 38 dB.
• the circulation pump in the said second washing program can be operated at a speed, which is the range of from 85 to 95 percent of the nominal speed and preferably at a speed which is less than 90 percent of the nominal speed.
• the circulation pump is operated at a speed of for example 1800 rpm, in the said second washing program the speed of the circulation pump can be reduced to 1600 rpm without deteriorating the washing result.
• the dishwasher during a first washing program that is designed as an intensive care program in which the circulation pump is operated at a speed of for example 2400 rpm, it was found that by providing for soaking steps in the second washing program the speed of the circulation pump can be reduced to 2200 rpm without deteriorating the washing result.
• the soaking step which follows the pre- washing step has a duration of at least 15 minutes, preferably of at least 20 minutes, wherein the pre-washing step as such preferably has a duration of at least 10 minutes, and more preferred, of at least 15 minutes.
• a detergent can be dissolved in the water which is circulated within the washing tub during the pre-washing step.
• a soaking step with non-heated water after conclusion of the pre-washing step, dirt particles are effectively removed from the washing goods in a very energy-effective and hence cost-effective manner.
• soaking step(s) can also very effectively be included in the washing step, during which heated cleaning liquid is sprayed onto the articles to be cleaned.
• heat is provided to the cleaning liquid during a first part of the washing step, which warmed cleaning liquid then is circulated within the washing tub without providing additional heat to the cleaning liquid.
• the washing step is not restricted to such temperature profile but may comprises further parts before, after or in between the said first and second part during which heated or non-heated cleaning liquid is circulated within the washing tub.
• a very effective timing for a soaking step was found to be in the last part of the washing step or after the washing step.
• the washing step usually most of the soil particles, which during the pre-washing step were wetted and soaked, are dissolved and removed from the washing goods.
• Some soiling types such as starch-containing soils or baked soil particles, require more time for their removal in addition to the chemical and mechanical cleaning effected during the washing step.
• Such additional time for dissolving persistent soiling and thus achieve satisfactory washing results can be provided for in a second soaking step following one of the washing steps.
• Such soaking step following the washing step preferably has a duration of at least 15 minutes, and more preferred has a duration of at least 20 minutes. While such soaking step following the washing step is referred to herein as "second soaking step", it should be understood that such optional soaking step can be employed either in addition or alternatively to the soaking step following the pre-washing step.
• the said second soaking step also can comprise a first soaking pause which is provided during said first part of the washing step, i.e. during warming of the cleaning liquid, as well as a second soaking pause that is provided during the second part of the washing step in which the cleaning liquid is circulated within the washing tub without providing additional heat to the cleaning liquid.
• a first soaking pause which is provided during said first part of the washing step, i.e. during warming of the cleaning liquid
• a second soaking pause that is provided during the second part of the washing step in which the cleaning liquid is circulated within the washing tub without providing additional heat to the cleaning liquid.
• such soaking pauses preferably have a duration of 5 to 15 minutes, and most preferred of at about 10 min.
• the cleaning action can be further improved, if the washing step, in addition to a first part during which heat is provided to the cleaning liquid and a second part during which the cleaning liquid is circulated within the washing tub without providing additional heat, i.e. during which the cleaning liquid is circulated while cooling, comprises a third part during which the temperature of the cleaning liquid is kept constant, preferably at the enzyme temperature, which in most cases will be between 40 and 45°C and preferably is about 42°C.
• the circulation pump and hence the spray arms within the dishwasher are inactive, during such heating pause in which the temperature of the cleaning liquid is kept constant, the circulation pump and hence the spraying arms may be active.
• a third preferred time interval for providing for a soaking pause is prior to the rinsing step, which usually constitutes the last step in the washing cycle.
• fresh water is sprayed onto the washing goods so as to wash off loosened soil particles and any remaining detergent.
• the washing goods furthermore are heated to a higher temperature, for example, to 70 0 C, so as to provide for a self drying effect when the circulation of the cleaning liquid is terminated and the washing tub is drained.
• the said soaking step can be effected during or at the conclusion of the intermediate rinsing step.
• This final soaking step also could be provided for after conclusion of an intermediate rinsing step, i.e. after water, preferably cold fresh water, that has been sprayed onto the washing goods has been drained from the washing tub.
• While said soaking step preceding the rinsing step preferably has a duration of at least 20 minutes, best results were achieved when such soaking step had a duration of about 30 minutes.
• the noise reduction which can be achieved by being able to operate the circulation pump at least during part of the washing cycle at a lower speed than the nominal speed can be further assisted by operating the circulation pump in a pulsed mode, i.e. by continuously varying the speed of the pump, because it was found that the operating noise created during operation of the circulation pump in pulse mode creates a less disturbing sound impression with the user.
• the circulation pump preferably is operated in the entire second washing program at a speed which is reduced with respect to the nominal speed.
• Preferred embodiments of the method for operating a dishwasher as suggested herein are described below by reference to the attached drawings, in which:
• Fig. 1 is a schematic representation of a washing program for a dishwasher as it is used in prior art dishwashers;
• Fig. 2 is a schematic representation similar to that shown in Fig. 1, illustrating a program flow for a dishwasher which is operated in accordance with the present invention
• Fig. 3 is a schematic representation of an alternative program flow for a dishwasher which is operated in accordance with the present invention.
• Fig. 1 shows an example of a washing program as it may be used also in a conventional dishwasher.
• Such washing program typically comprises a pre-wash step, in which the articles to be cleaned are subject to an initial cleaning step for removing coarse soil particles as well as dirt which easily can be removed from the washing goods.
• a main wash step is conducted, typically at a temperature that is higher than the temperature employed in the pre-wash step, wherein during the main wash step also the more persistent soil particles are loosened and removed from the washing goods.
• the washing goods are exposed to a cold rinse step during which the loosened dirt particles and detergent are washed-off from the washing goods.
• heated fresh water is sprayed onto the washing goods to fully clean the latter and at the same time supply heat to the washing goods, which serves for drying the washing goods.
• the pre-wash step begins with a drain sub-step, during which the drain pump is activated, so as to remove any liquid that has accumulated in the sump of the dishwasher during a previous cleaning cycle.
• the drain pump Upon having activated the drain pump for a certain amount of time or until no further liquid is withdrawn from the sump of the dishwasher, fresh water is fed into the dishwasher and a circulation pump is activated so as to feed such water to rotatable spray arms and thus to spray it onto the articles to be cleaned, which typically are arranged on dish racks, such as a lower and an upper dish rack, provided within the washing chamber of the dishwasher.
• the pre-wash step can be carried out either with cold water, i.e.
• the pre-wash step is carried out at a temperature of between 15 and 55 0 C.
• a detergent can be added to the water circulated within the dishwasher, which detergent can be added to the cleaning liquid either by a detergent dispenser, a detergent compartment that is flushed with cleaning liquid, or by using multi- component detergents which are provided in the form of tablets containing a plurality of active agents that are dissolved into the cleaning liquid at different times during the cleaning cycle.
• the drain pump is activated, so as to remove the cleaning liquid and any dirt particles that were dissolved from the washing goods.
• a main wash step during which warmed cleaning liquid is circulated within the dishwasher, i.e. first fresh water is fed into the washing tub and then the circulation pump is activated, so as to feed water which collects within the sump of the dishwasher to the spray arms that are located below or above the dish racks, on which the articles to be cleaned are arranged, so as to spray the cleaning liquid onto the washing goods.
• the cleaning liquid typically is heated to a temperature in the range of from 30 to 70 °C.
• the circulation pump Upon having sprayed cleaning liquid onto the washing goods for a certain amount of time, the circulation pump is deactivated and the cleaning liquid, now containing dissolved detergent as well as soil and dirt particles that have been washed-off from the washing goods, is drained from the sump of the dishwasher by activation of the drain pump.
• the washing cycle comprises a number of rinsing steps during which water is fed into the dishwasher and the circulation pump is operated so as to rinse remaining dirt particles and detergent from the goods to be cleaned.
• the circulation pump is operated so as to rinse remaining dirt particles and detergent from the goods to be cleaned.
• some detergent may be present in the cleaning liquid, for example, when multi-component cleaning tabs are used that may not have fully dissolved during the pre- wash and main wash steps.
• certain further treating agents may be added to the cleaning liquid, possibly also by the use of multi-component cleaning tabs, such as specific glass treating agents or the like.
• the initial rinsing step typically is carried-out at a lower temperature of, for example, 30 to 40 0 C
• a higher temperature for example, 35 to 70 0 C is used, so as to heat the rinsed washing goods to thus facilitate drying of the washing goods.
• the sump may be emptied by activating the drain pump.
• any of the individual steps of the washing program may comprise several sub-steps, such as the main wash step being divided into plural washing phases which are carried-out at different temperatures.
• the cleaning liquid used within the washing compartment can be exchanged between such sub-phases by activating the drain pump upon termination of the first phase and feeding fresh water into the washing compartment at the beginning of the second phase.
• the circulation pump can be operated at a single speed so as to provide for a certain water pressure with which the cleaning liquid is sprayed onto the articles to be cleaned.
• the dishwasher may be designed to operate the circulation pump at a higher speed. Since, however, a higher water pressure may cause damages of certain articles, such as fine glass ware or the like, the use of a higher speed of the circulation pump and correspondingly of a higher water pressure during any of the washing cycles should be activated only on specific request by the user, such as by selecting an "intensive care" program or the like.
• Fig. 2 shows a washing program, which comprises similar program steps as the ones shown in Fig. 1, but wherein there are provided several soaking pauses, during which the circulation pump is inactive and which serve for providing additional time for the cleaning liquid and any active agents added thereto to soak into the dirt particles adhering to the articles to be cleaned.
• the soaking pauses also could be employed before draining the dishwasher.
• the soaking step or soaking pause should have a duration of several minutes, that is preferably of between 5 and 30 minutes, so as to allow for sufficient time to provide for sufficient soaking.
• the user of the dishwasher thus can select between a number or "regular” washing programs, such as an automatic program or standard programs that are carried out at different temperatures, such as at 40 "C, 50 0 C or 65 0 C, an intensive washing program carried out at a higher temperature of for example 70 0 C, or a quick cleaning program having a shortened program duration.
• regular washing programs such as an automatic program or standard programs that are carried out at different temperatures, such as at 40 "C, 50 0 C or 65 0 C, an intensive washing program carried out at a higher temperature of for example 70 0 C, or a quick cleaning program having a shortened program duration.
• common to all these programs is that the circulation pump is operated at a nominal speed that is optimized in terms of the cleaning efficiency and which may be the same in all washing programs.
• the user can also select a silent mode, in which, for at least part of the respective program and preferably for the entire program, the circulation pump is operated at a speed which is reduced with respect to said nominal speed, and in which there is provided at least one soaking step during which the circulation pump is inactive.
• Fig. 3 shows a portion of a modified main wash step as it could be employed in an overall washing program as it is shown in Fig. 2.
• Fig. 3 shows a main wash step which comprises several sub-phases, namely a first main wash phase during which a°mildly warmed cleaning liquid having a temperature of about 30 to 45 0 C is sprayed onto the articles to be cleaned and in which during a second main wash phase the cleaning liquid is warmed to a higher temperature of generally 40 to70 0 C.
• there are provided two soaking pauses in such main wash step namely a first soaking step following the first washing phase, and a second soaking pause in the terminal phase of the main wash step.
• the cleaning liquid is not drained from the washing tub between the first and second main wash phases, but rather upon termination of the lower temperature first main wash phase only the circulation pump is deactivated, and upon termination of the first soaking pause heat is provided to the washing tub and hence to the cleaning liquid present therein when the circulation pump is again activated to carry out the second main wash phase.
• Fig. 3 thus shows an embodiment in which the sump of the dishwasher is drained upon deactivation of the circulation pump upon conclusion of the second main wash phase but before the soaking pause of the second main wash phase, if preferred the cleaning liquid could also be partially or fully exchanged during the first and second main wash phases.
• the cleaning result is most efficient, when the first and or the second soaking pause in the main wash step is carried-out at a temperature of 40 to 45°C and most preferably of about 42°C. In this manner, particularly advantageous conditions are realized in the washing compartment for the cleaning agent to perform its cleaning activity.

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• Washing And Drying Of Tableware (AREA)
• Cleaning By Liquid Or Steam (AREA)

Priority Applications (6)

Applications Claiming Priority (2)

Publications (1)

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ID=40427230

Family Applications (1)

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Citations (9)

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• 2008
  • 2008-10-31 EP EP08019155.4A patent/EP2181636B1/de active Active
  • 2008-10-31 PL PL08019155T patent/PL2181636T3/pl unknown
• 2009
  • 2009-10-23 WO PCT/EP2009/007587 patent/WO2010049097A1/en active Application Filing
  • 2009-10-23 AU AU2009310033A patent/AU2009310033B2/en not_active Ceased
  • 2009-10-23 CA CA2737080A patent/CA2737080C/en not_active Expired - Fee Related
  • 2009-10-23 RU RU2011121885/12A patent/RU2515369C2/ru not_active IP Right Cessation
  • 2009-10-23 US US13/122,862 patent/US20110192426A1/en not_active Abandoned
  • 2009-10-23 KR KR1020117007120A patent/KR101775734B1/ko active IP Right Grant
  • 2009-10-23 CN CN200980140659.4A patent/CN102186394B/zh not_active Expired - Fee Related

Patent Citations (9)

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