METHOD FOR OPERATING A LAUNDRY WASHING MACHINE AND LAUNDRY WASHING MACHINE

Abstract

 Method for operating a laundry washing machine (1) for treating laundry with a washing liquid, and corresponding washing machine (1), comprising a casing (2) in which a rotatable drum for acceptance of laundry is arranged, further comprising a fresh water supply (5), further comprising a tub (3) in which said drum is arranged, further comprising a heater (10) for heating washing liquid, further comprising a detergent storage container (6) with at least one compartment (6f, 6g, 6h) for collecting a laundry treatment agent, whereby a laundry treatment procedure is performed in which at least one washing phase, at least one rinsing phase, and at least one spinning phase are performed, whereby said heater (10) is always switched off during said washing, rinsing and spinning phases.

Description

Field of the invention

[0001] The present invention concerns the field of operating methods for washing machines for treating laundry. In particular, the present invention refers to a method for operating a washing machine efficiently.

Background Art

[0002] Nowadays the use of laundry washing machines, both "simple" laundry washing machines (i.e. laundry washing machines which can only wash and rinse laundry) and laundry washing-drying machines (i.e. laundry washing machines which can also dry laundry), is widespread.

[0003] In the present description the term "laundry washing machine" will refer to both simple laundry washing machines and laundry washing-drying machines. Laundry washing machines generally comprise an external casing provided with a washing tub which contains a rotatable perforated drum where the laundry is placed. A loading/unloading door ensures access to the drum. Laundry washing machines typically comprise a water supply unit or fresh water supply and a products supply unit or detergent storage container, preferably a drawer, for the introduction of water and washing/rinsing products (i.e. detergent, softener, rinse conditioner, etc.) into the tub. Known laundry washing machines are also provided with water draining devices that may operate during different phases of the washing program to drain the dirty water.

[0004] According to the known technique, a complete treating program typically includes different phases during which the laundry to be washed is subjected to adequate treatments. A treating cycle usually comprises a main washing phase during which the laundry is treated by means of water and a detergent. The water is typically heated to a predetermined temperature, usually by a heater placed on the tub, based on the washing program selected by the user. During the main washing phase the drum is rotated, so as to apply also a mechanical cleaning action on the laundry. At the end of the main washing phase the drum is typically rotated at high rotational speed, so in such a way that dirty washing liquid (i.e. water mixed with detergent) is extracted from the laundry, and this dirty washing liquid is drained to the outside by the water draining devices.

[0005] A successive step of the cycle typically comprises a rinsing phase which usually comprises one or more rinsing cycles/steps. In a rinsing cycle, clean rinse water may be first added to the laundry. The rinse water is absorbed by the laundry and the rinse water removes from the laundry detergent and/or dirty water not previously removed by washing liquid in the main washing cycle. In case that rinsing products are used during the rinsing phase, the water and the rinsing products are usually heated to a predetermined temperature. The drum is then rotated to extract water and dirty water/detergent from the laundry: the dirty water extracted is drained from the tub to the outside by the water draining devices.

[0006] After a rinsing phase, one or more final spinning phases may be provided for the extraction of the residual water contained in the wet laundry through the rotation of the drum at high speed. The water extracted during the spinning phase is drained towards the outside by means of the water draining devices (during or after the spinning phase).

[0007] The laundry treatment is typically performed by a temperature higher than ambient temperature, for instance 30°C, 40 °C, 60 °C, 90 °C. To this end, the washing liquid is heated by a heater during the described phases. As the operation of the heater consumes considerable energy, in order to conform to modern standards of energy saving it is desirable to spend less energy but at the same time not to reduce the quality and the reliability of the laundry treatment process.

[0008] The object of the present invention is therefore to provide a method for operating a laundry washing machine which is very efficient with respect to energy consumption. Another object of the invention is to provide a laundry washing machine which allows a very energy efficient and reliable treatment of laundry.

Disclosure of invention

[0009] In a first aspect, the invention relates to a method for operating a laundry washing machine for treating laundry with a washing liquid, comprising a casing in which a rotatable drum for acceptance of laundry is arranged, further comprising a fresh water supply, further comprising a tub in which the drum is arranged, further comprising a heater for heating washing liquid, further comprising a detergent storage container with at least one compartment for collecting a laundry treatment agent, whereby a laundry treatment procedure is performed in which at least one washing phase, at least one rinsing phase, and at least one spinning phase are performed, and whereby the heater is always switched off during the washing, rinsing and spinning phases.

[0010] Preferred embodiments of the invention are described in relation to the dependent claims and the description of the enclosed drawings.

[0011] The invention is based on the consideration that the operation of the heater causes a significant part to the total energy consumption of the laundry treatment process involving washing, rinsing and spinning phases.

[0012] Applicant has found that an especially energy efficient laundry treatment routine can be achieved without heating the washing liquid in time intervals of respective washing, rinsing, or spinning phase, because once the temperature of the washing liquid has been stabilized, due to its heat exchange with the laundry and the ambient, the carrying out of several phases with the same liquid temperature allows an efficient and reliable cleaning result. Applicant has found that the quality of the laundry treatment process is not reduced, or is not reduced of a considerable value, and at the same time the energy consumption is lowered compared to usual routines in which the heater is on or active during these phases.

[0013] The expression that the heater is always turned off during the washing, rinsing and spinning phases most preferably encompasses that the heater is permanently in an off state and is not heating the washing liquid during these phases.

[0014] In a preferred embodiment, in at least one of the phases the water coming from the fresh water supply is softened before reaching said tub. Applicant has found that not heating the washing liquid during the washing, rinsing and spinning phases in conjunction with the softening of the water of the washing / rinsing liquid leads to large energy savings and still a high cleaning efficiency even if the temperature of the washing / rinsing liquid is not as high as in known routines. Under identical conditions of the laundry treatment process, especially with the same textiles and the same water temperature, a higher cleaning efficiency can be achieved with softened water. In the present case, the increase of the efficiency by softening of water at least to some extent can balance out the decrease in efficiency stemming from keeping the heater off during all washing, rinsing and spinning stages.

[0015] Preferably, the heater is arranged in a drainage area of the tub / of the washing machine. Washing liquid can collect in the drain area and be heated efficiently.

[0016] Advantageously, a first recirculation pump is provided for recirculating washing liquid through a first recirculation pipe from a first region at or near the bottom of the tub to a second region of the tub, whereby the first recirculation pump is switched on at least temporarily during the at least one washing phase and/or rinsing phase. This recirculation of washing liquid improves the wetting and the soaking of the laundry.

[0017] Preferably, the second region is located at or near the top of the tub, which refers to the tub in the mounted position of the washing machine for performing the laundry treatment procedure. In this way, the distribution of washing liquid (detergent plus water) among the textiles and wetting of the laundry are greatly improved, thereby increasing the efficiency of the treatment process.

[0018] In order to further improve the wetting of the laundry, the washing liquid advantageously is essentially flushed / sprayed from the second region, especially near or at the top of the tub, down into the tub.

[0019] Preferably, a second recirculating pump is provided for recirculating washing liquid through a second recirculation pipe from a third region at or near the bottom of the tub to a fourth region at or near the bottom of the tub, and whereby the second recirculating pump is switched on at least temporarily during the at least one washing phase and / or rinsing phase. In this way, the homogeneity of the washing liquid which comprises water and at least one laundry treatment agent such as detergent or softener or a bleaching agent is improved. In this way, the efficiency of the laundry treatment procedure is enhanced. Especially the combination of softening the water, mixing detergent and water by the second recirculation circuit and distributing this mixture among the textiles by the first recirculation circuit can counter the decrease in efficiency stemming from not heating the washing liquid. While heat improves the distribution of treatment agent, this effect can be provided at least partly by the mixing circuits described above, making it possible to accept lower temperatures of the washing liquid.

[0020] In a preferred embodiment, the third and the fourth region are essentially the same region. In this way, washing liquid is recirculated from the bottom of the tub through a circulation pipe again to the bottom of the tub, preferably without touching the drum/tub, thereby mixing the water and the laundry treatment agents.

[0021] Preferably, the third region corresponds to the first region, i.e. both circulation circuits transport washing liquid from essentially the same region of the tub to the corresponding further region.

[0022] Advantageously, the fourth region, in the mounted position of the machine, is more elevated than the third region.

[0023] For softening the water, the washing machine preferably comprises a water softening device which is arranged within the casing and which is fluidly arranged between the fresh water supply and/or the tub or the detergent storage container and whereby in at least one of said phases the water coming from the fresh water supply passes through the water softening device before reaching the detergent storage container / the tub. The water softening device is preferably no component external to the machine but integrated in the machine. The fluid arrangement between fresh water supply and tub can include pipes, container or other components which can carry washing liquid.

[0024] In a preferred embodiment, the washing machine comprises a first water circuit by which water from the fresh water supply is transferred to the tub and / or the detergent storage container after passing through the water softening device and further comprises a second circuit by which water from the fresh water supply is transferred into the tub and / or the detergent container while bypassing the water softening device, whereby in at least one of these phases the water coming from the fresh water supply passes through the first water circuit. It can thus selectively chosen every time that water from the fresh water supply is taken if it should be softened, thereby controlling the resourced needed for softening the water.

[0025] The first circuit advantageously is configured to channel the softened water selectively into one of the compartments of the detergent storage container.

[0026] Preferably, the water softening device comprises a container for a water softening agent through which water is guided before it is channelled into a compartment of the detergent storage container. The term "detergent storage container" encompasses one or several compartments for storing detergent but also any other kind of laundry treatment agent.

[0027] In a preferred embodiment, during the laundry treatment procedure, the heater is never turned on. The heater thereby is staying in its off state during all phases, leading to a string reduction of energy consumption of the whole process.

[0028] In a preferred embodiment, in a washing phase the drum is rotated at least temporarily with a first speed, wherein in a rinsing phase the drum is rotated at least temporarily with a second speed, and wherein in a spinning phase the drum at least temporarily is rotated with a third speed which is higher than the first and/or second speed to expel water from the laundry and bring it into the drainage area.

[0029] The invention also preferably relates to a method for operating a laundry washing machine for treating laundry with a washing liquid, comprising a user interface, whereby on the user interface of the washing machine a laundry treatment program is selectable, and whereby, if this program is selected and the laundry treatment procedure is switched on, a method as described above is performed.

[0030] In a second aspect, the invention relates to a laundry washing machine comprising a casing in which a rotatable drum for acceptance of laundry is arranged, further comprising a fresh water supply, further comprising a tub in which the drum is arranged, further comprising a heater for heating washing liquid, further comprising a detergent storage container with at least one compartment for collecting a laundry treatment agent, further comprising a control unit in which a method described above is implemented.

[0031] Preferably, the washing machine comprises a water softening device which is arranged within the casing and which is fluidly arranged between the fresh water supply and the tub and / or the detergent storage container.

[0032] Advantageously, the laundry washing machine comprises a first water circuit by which water from the fresh water supply is transferred to the tub and / or the detergent storage container after passing through the water softening device and comprises a second circuit by which water from the fresh water supply is transferred into the tub and / or the detergent container while bypassing the water softening device.

[0033] Preferably, the first circuit is configured to channel the softened water selectively into one of the compartments of the detergent storage container.

[0034] The water softening device preferably comprises a container for a water softening agent through which water is guided before it is channelled into a compartment of the detergent storage container and/or guided directly into the tub.

[0035] Preferably, the washing machine comprises a user interface, whereby on this user interface of said washing machine, a laundry treatment program is selectable, and whereby, if said program is selected, said heater is never turned on. The heater is therefore during the whole laundry treatment process remaining in its off state, thereby not consuming energy throughout the process. This leads to a very energy-saving treatment process.

[0036] Preferably, the laundry washing machine is a "simple" washing machine or a combined washer/dryer. The washing machine is preferably a horizontal axis washing machine.

[0037] The advantages of the invention are especially as follows. The energy efficiency is considerably improved by consequently not heating the washing liquid during the washing, rinsing, and spinning phases. In conjunction with the process of softening the water of the washing / rinsing liquid, a high quality of the washing can be maintained at a reduced temperature of the washing liquid, thereby even further lowering the energy consumption. A water softening device integrated into the washing machine offer the user a convenient way to allow the softening of the water.

Brief description of the drawings

[0038] Further characteristics and advantages of the present invention will be highlighted in greater detail in the following detailed description of preferred embodiments of the invention, provided with reference to the enclosed drawings and given as an indication and not for limiting purposes.

[0039] In particular, the attached drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification. The drawings together with the description explain the principles of the invention. In the drawings, corresponding characteristics and/or components are identified by the same reference numbers. In these drawings:

FIG. 1

shows a front-loading laundry washing machine in a perspective view;

FIG. 2

shows the laundry washing machine according to FIG. 1 in a perspective view with the casing removed;

FIG. 3

shows the laundry washing machine according to FIG. 1 in another perspective view with the casing removed;

FIG. 4

shows a cross section of the laundry washing machine according to FIG. 1 without some components;

FIG. 5

shows a view of a portion of the hydraulic circuit of the laundry washing machine according to FIG. 1;

FIG. 6

shows the laundry washing machine of FIG. 1 with a drawer in a retracted state in a perspective view;

FIG. 7

shows the laundry washing machine according to FIG. 6 with a top plate removed in a perspective view;

FIG. 8

shows a drawer in an explosive view;

FIG. 9

shows the laundry washing machine of FIG. 7 in a top view;

FIG. 10

shows a preferably embodiment of a drawer assembly comprising a water softening device in a first perspective view;

FIG. 11

shows the embodiment of a drawer assembly comprising the water softening device of FIG. 10 in a second perspective view;

FIG. 12

shows the embodiment of a drawer assembly comprising the water softening device of FIG. 10 in a third perspective view;

FIG. 13

shows a cover of the drawer of FIG. 10 in an explosive view;

FIG. 14

shows a flow chart of a method for operating a laundry washing machine in a first preferred embodiment; and

FIG. 15

shows a flow chart of a method for operating a laundry washing machine in a second preferred embodiment.

[0040] Same parts in the figures are labelled by identical reference numbers.

[0041] With reference to FIGs. 1 to 7, a front-loading laundry washing machine 1 is shown which comprises an external housing or casing 2 comprising two side walls, a front wall, a back wall (not shown) and a top plate. Washing machine 1 further comprises a front panel 6b with a user interface 6c, preferably comprising indicators for the current state of the machine and/or user elements. Front panel 6b further comprises a user element 6d for interacting with the machine which is preferably built as a rotatable push button. Next to the front panel 6b an extractable drawer 6a is provided, as described below.

[0042] Inside casing 2, a washing tub 3 is provided which contains a perforated washing drum into which the laundry to be treated can be loaded. The tub 3 and the drum have both preferably an essentially cylindrical shape. Tub 3 is preferably suspended in a floating manner inside casing 2, advantageously by means of a number of coil springs and shock absorbers 9.

[0043] Casing 2 is provided with a door 8 for loading / unloading of laundry with a handle 8a for operating the door 8. The drum is advantageously rotated by an electric motor (not shown) which preferably transmits the rotating motion to a shaft of the drum, advantageously by means of a belt/pulley system. In a different embodiment, the motor can directly be associated with the shaft of the drum. Tub 3 is preferably connected to casing 2 by means of an elastic bellows 7 or gasket. Tub 3 preferably comprises two complementary hemi-shells 13, 14 structured for being reciprocally coupled to form tub 3. The bottom region 3a of tub 3 preferably comprises a seat or sump 34, suitable for receiving a heating device or heater 10. The heater 10, when activated, in the present preferred embodiment, heats the liquid inside sump 34. The heater 10 preferably is arranged in a draining region of washing machine 1.

[0044] A water supply circuit 5 (see Fig. 3) which can be built according to the known art is arranged at the upper part of the laundry washing machine 1 and is suited to supply water into tub 3. It advantageously comprises at least one supply valve which is properly controlled, opened and closed, during the washing / rinsing cycle. In the present embodiment, water supply circuit comprises three supply valves. Respective inlets are connected to a fresh water supply or water mains, while respective outlets are connected to pipes for delivering water into a flushing device 100 provided on a detergent storage container 6 provided on the washing machine 1.

[0045] The drawer assembly / detergent storage container 6 is configured to supply detergents and/or rinsing or other laundry treatment agents into tub 3. The drawer assembly 6 comprises on its frontal side an extractable drawer 6a preferably provided with various compartments 6f, 6g, 6h (see FIGs. 9-11) suited to be filled with washing products, especially a detergent, and at least one a rinse additive, especially a fabric softener.

[0046] Said extractable drawer 6a may comprise still further compartments suited to be filled with other type of rinse additives, such as fabric conditioners, waterproofing agents, fabric enhancers, rinse sanitization additives, chlorine-based additives, i.e. products which are suitable to be used in the rinsing phase of the washing program (as will be described in details along this description).

[0047] In the preferred embodiment here illustrated, the water is supplied into the tub 3 from the water supply circuit 5 by making it flow through the flushing device 100 of drawer assembly 6, through one of the compartment of the extractable drawer 6a and then through a supply pipe 110. The water which reaches the tub 3 can, in this case, selectively contain one of the products contained in the compartments of the drawer 6a. Such water can be clean if the product in the drawer 6a has been already removed. In an alternative embodiment of the invention, a further separate water supply pipe can be provided in the drawer assembly or through an additional pipe, which supplies exclusively clean water into the tub 3, thus bypassing the compartments of the drawer 6a.

[0048] The water supply circuit 5 also preferably comprises a water flow sensor, for example a flow meter, which makes it possible to calculate the quantity of water supplied into the tub 3. The supply pipe 110 is preferably arranged laterally with respect to the tub 3 and preferably terminates at an upper region of the tub 3. More preferably, the supply pipe terminates at a rear side of the washing tub 3.

[0049] The water supply circuit 5 in the preferred embodiment comprises a water softening device 120 (see FIGs. 10-12) for removal of calcium, magnesium and/or certain other metal cations in hard water before entering the tub. The water softening device 120 advantageously comprises water softening agents for reducing the hardness degree of the water to be supplied to the washing tub. Furthermore, the water supply circuit 5 may comprise a regeneration-agent reservoir 104 which is preferably housed inside the extractable drawer 6a and is structured for receiving salt or other regeneration agents for regenerating a water softening function of the water softening agents.

[0050] Laundry washing machine 1 advantageously comprises a water outlet circuit 25 suitable for withdrawing liquid from a bottom region of the tub 3. The water outlet circuit 25 preferably comprises a main pipe 17 (see FIGs. 4 and 5) a draining pump 26 and an outlet pipe 28 ending outside the housing or casing 2.

[0051] The water outlet circuit 25 or draining circuit preferably further comprise a filtering device 12 arranged between the main pipe 17 and the draining pump 26. The filtering device 12 is adapted to retain all, or the majority of the undesirable bodies (for example buttons that have come off the laundry, coins erroneously introduced into the laundry washing machine, etc.). This filtering device 12 can preferably be removed, and then cleaned, through a gate 40 (see FIG. 1) placed advantageously on the front wall of the housing casing of the laundry washing machine 1.

[0052] The main pipe 17 connects the bottom region of the tub 3 to the filtering device 12. An inlet end 17a of the main pipe is advantageously positioned at the lower point of the tub 3, more preferably at the lower point of the sump 34. An outlet end of the main pipe is connected to a front part of the filtering device 12.

[0053] In a further embodiment, not illustrated, the filtering device 12 may be provided directly in the tub 3, preferably obtained in a single piece construction with the latter. In this case the filtering device 12 is fluidly connected to the outlet of the tub 3, in such a way that water and washing liquid drained from the tub 3 enters the filtering device 12.

[0054] The draining pump 26 is preferably connected to the body of the filtering device 12 (see Fig.5) and conveys the liquid to the outlet pipe 28 through an outlet. Activation of the drain pump 26 drains the liquid, i.e. dirty water or water mixed with washing and/or rinsing products, from the tub 3 to the outside.

[0055] Laundry washing machine 1 preferably comprises a first recirculation circuit 20 adapted to drain liquid from the bottom region 7a of the tub 3 and to re-admit the liquid into a second region 20a, or upper/higher region, of the tub 3; in other words, the outlet 23a of the first recirculation circuit 20 is located at a position higher that the position of the inlet 17a of the first recirculation circuit 20 corresponding to the inlet of the main pipe 17 connected to the bottom side of the tub 3. The first recirculation circuit 20 preferably comprises a first recirculation pump 21, a first pipe 22 connecting the filtering device 12 to the first recirculation pump 21 and a second recirculation pipe 23, preferably provided with a outlet / terminal nozzle 23a arranged preferably at the upper region 20a of the tub 3. The terminal nozzle 23a is preferably arranged so that the liquid is flushed/sprayed directly into the drum. More preferably the outlet / terminal nozzle 23a is integrally formed in the bellows, and the liquid is therefore advantageously flushed / sprayed in a direction the center of the perforated drum. The outlet / terminal nozzle 23a, therefore, enhances distribution of liquid over the laundry through the perforated drum.

[0056] The liquid from the bottom region 7a of the tub 3 is conveyed towards the upper region 20a of the tub 3 by activation of the first recirculation pump 21. The first recirculation circuit 20 is advantageously activated in order to improve wetting of the laundry inside the drum and for reducing the water required in the whole washing program. In general, the first recirculation circuit 20 is properly realized for transferring a portion of a liquid from a bottom region 7a of the tub 3, preferably from the sump 34, to an upper region of the tub 3 in order to enhance absorption of the liquid by the laundry.

[0057] Laundry washing machine 1 advantageously comprises a second recirculation circuit 30 or mixing circuit. The mixing circuit is adapted to drain liquid from the bottom region of the tub 3 and to re-admit such a liquid (recirculated mixing liquid) into a first region of the tub, which corresponds substantially to the same bottom region of the tub 3. Preferably, the second recirculation circuit 30 is adapted to drain liquid from the bottom of the sump 34 and to re-admit such a liquid (recirculated mixing liquid) again into the sump 34. More preferably, the liquid is re-admitted again into the sump 34 below the heater 10. More preferably, the outlet 34a (see Fig. 4) of the second recirculation circuit 30 is a position higher that the position of the inlet 17a of said second recirculation circuit 30 corresponding to the inlet of the main pipe 17 connected to the bottom side of the tub.

[0058] The mixing circuit preferably comprises a second recirculation pump 31, a second pipe 32 connecting the filtering device 12 to the second recirculation pump 31 and a second recirculation pipe 33 advantageously provided with a terminal portion 34a, or nozzle. The terminal portion 34a advantageously ends inside the sump 34, as mentioned above.

[0059] The liquid from the bottom region 7a of the tub 3 is conveyed again towards the bottom region of the tub by activation of the second recirculation pump 31. Advantageously, the liquid from the bottom region 7a of the tub 3 is conveyed towards the bottom region 7a of the tub 3 in a gap between the tub 3 and the drum. In a further embodiment, not illustrated, the mixing circuit may comprise a dedicated pipe connecting the bottom region of the tub 3 to the recirculation pump; in this case the mixing circuit is advantageously completely separated from the water outlet circuit, i.e. completely separated from the filtering device 12 and the main pipe 17.

[0060] The mixing circuit (second recirculation circuit 30) is preferably realized for transferring a portion of a liquid from a bottom region of the tub to the same bottom region for mixing and/or dissolution of the products, as better described below. In general, the mixing circuit (second recirculation circuit) is preferably realized for transferring liquid from a bottom region of the tub and for re-admitting such a liquid into the washing tub such that at least a portion of the re-admitted liquid reaches the bottom region of the washing tub without entering the washing drum.

[0061] More preferably, the mixing circuit (second recirculation circuit 30) is preferably realized for transferring liquid from a bottom region of the tub and for re-admitting such a liquid into the washing tub such that all, or substantially all, the re-admitted liquid reaches the bottom region of the washing tub without entering the washing drum. Advantageously, laundry washing machine 1 comprises a device suited to sense (or detect) the liquid level inside the tub 3. The sensor device preferably comprises a pressure sensor which senses the pressure in the tub 3. From the values sensed by the sensor device it is possible to determine the liquid level of the liquid inside the tub 3. In another embodiment, not illustrated, laundry washing machine 1 may preferably comprise (in addition to or as a replacement of the pressure sensor) a level sensor (for example mechanical, electro-mechanical, optical, etc.) adapted to sense (or detect) the liquid level inside the tub 3.

[0062] In a preferred embodiment, the heater 10 is arranged in the drainage area of the washing machine 1, whereby near the first and/or the second circulation pump 21, 31 and/or near the first and/or second circulation pipe a water level in a drainage area is increased by means of a rinsing / spinning phase or a water charge while the heater 10 is turned off, and wherein the water level is increased until the heater 10 is at least partially submerged by washing liquid.

[0063] Preferably, the washing liquid is circulated via the first and/or the second circulation pumps 21, 31 and at least a part of the washing liquid is thus again bound in the laundry such that the water level in the drainage area decreases at least below the top side of the heater 10, and whereby the heater 10 is maintained turned off when the water level is below the top side of the heater 10.

[0064] Laundry washing machine 1 comprises a control unit, connected to the various parts of the laundry washing machine in order to ensure its operation. The control unit is preferably connected to the water inlet or supply circuit 5 (i.e. to supply valve), the water outlet circuit (i.e. to the draining pump 26), the recirculation circuits 20, 30 (i.e. to the recirculation pumps 21, 31), the heater 10 and the electric motor and receives information from the various sensors provided on the laundry washing machine 1, like possibly the pressure sensor, a temperature sensor, etc.

[0065] The user interface 6c is connected to the control unit, accessible to the user and by means of which the user may select and set the washing parameters, like for example a desired washing program. Usually, other parameters can optionally be inserted by the user, for example the washing temperature, the spinning speed, the load in terms of weight of the laundry to be washed, etc. Based on the parameters acquired by the interface 6c, the control unit sets and controls the various parts of the laundry washing machine 1 in order to carry out the desired washing program.

[0066] For draining liquid from the tub 3, the draining pump 26 is activated. Fresh water is introduced into tub 3 by activating the respective supply valve. The fresh or clean water is then preferably running through the flushing device 100 and then through a wash compartment and the outlet pipe 110, into the tub 3. The recirculation circuits 20, 30 can be employed as described above by activating/deactivating the respective first and/or second recirculation pump. The sensor for detecting the water level can be employed to monitor if the water level of free water is collecting in the tub 3, indicating for example that the laundry is not able to continue to absorb water and is in a saturated or even over-saturated state.

[0067] As mentioned above, laundry washing machine 1 preferably comprises, preferably inside the casing 2, a water softening device 120 which is arranged / interposed between the fresh-water supply circuit 5 and the flushing device 130, so as to be crossed by the fresh water flowing from the water waters mains towards the flushing device 130, and is structured for selectively reducing, during one or more laundry treatment phases, the hardness degree of the fresh water drawn from the water mains and channeled to the flushing device and then through at least one compartment 6f-h preferably comprised on the extractable drawer 6a.

[0068] The fresh-water supply circuit 5 preferably comprises also an electrically-controlled on-off valve 84 arranged/interposed between the water mains and the water softening device 80, and is able to control/regulate the flow of fresh water from the water mains towards the water softening device 80; a hosepipe 82 (see FIG. 9) connects on-off valve 84 directly to the inlet of the internal water softening device 120 which, in turn, has the outlet connected to the flushing device 130. In the example shown, in particular, the electrically controlled on-off valve 84 is preferably attached to the rear wall of casing 2.

[0069] As can be seen in FIG. 8, drawer 6a comprises a regeneration-agent container 90 for a regeneration-agent. A bottom inlay 94 has a meshed structure as to allow the fresh water spilled/poured into the container 90 to freely reach and at least partly dissolve the salt grains located inside the container 90 to form a given amount of brine which drops directly on a funnel-shaped catchment basin provided below the container 90. Container 90 is closed by a cover 98 which is shown in FIG. 13. Cover 98 comprises a bottom part 100, a frame 102 which is mounted on bottom part 100, and a lid 104 which is arranged on frame 102 and which comprises an extruding part or handle 106 by which lid 104 can be tiled as to gain access to container 90 for filling it with the regeneration agent.

[0070] The water softening device 120 comprises a water softening agent container which in the mounted position of drawer 6 is located below regeneration agent container 90.

[0071] The water softening device 120 furthermore preferably comprises a water supply circuit which is structured for channeling, on command, a given amount of fresh water into the regeneration-agent container 90 or reservoir so to at least partly dissolve the salt or other regeneration agents stored therein and form a given amount of brine (i.e. salt water); it preferably comprises an electrically-powered brine-circulating pump / valve which is interposed between the water-softening agent container 142 and the regeneration-agent container 90 and is structured for transferring/moving, when activated / switched, the brine (i.e. the salt water) from the regeneration-agent reservoir container 90 to the water-softening agent container.

[0072] Preferably, by operation of valves 50 or due to the commutation of a diverter, the water is lead to bypass the compartments of drawer 6a and/or softener device 120 and flows to the tub directly. In addition or alternatively, preferably a bypass of the compartments is provided (not shown) that can be provided on the flushing device 130, suitable to flush the fresh water to the tub /outlet pipe 110 directly.

[0073] Laundry washing machine 1 is adapted to conduct a method described below. To this end, the method is implemented in the control unit as software instructions and/or hardware circuit, wherein preferably the control unit comprises a processor on which software instructions are executed.

[0074] A first preferred embodiment of the method which is conducted in the control unit is shown as flow chart in FIG. 14 and is described also in relation to FIGs. 1 to 13 with the shown preferred embodiment of the washing machine 2. In a start step 200, the method starts. Block 200 can as way of example comprise the loading of the drum with laundry, filling at least one laundry treatment agent into drawer 6a, selecting a washing program and pushing a start button on the laundry washing machine 2. In a step 206, water is introduced into the tub 3, preferably via at least one of the compartments 6f, 6g, 6h; in this step the heater 10 is always maintained in a switched off state. In a subsequent step 218, a washing phase is performed. During the entire duration of the washing phase, the heater is remaining a switched-off-state.

[0075] In this way, energy consumption is strongly reduced compared to known washing procedures in which the washing liquid is heated at least partly during the washing phase. At the end of the washing phase in a preferable draining phase or step 222, washing liquid is drained from the tub 3.

[0076] In a subsequent step 226, fresh water is introduced into the tub 3, preferably via at least one of the compartments 6f, 6g, 6h. A subsequent step 228 is a rinsing phase during which the laundry in the drum is rinsed. During step 228 the heater is remaining in an off-state.

[0077] In a subsequent step 232, water is preferably again drained from the tub 3. In a subsequent spinning phase, during which the heater is not activated and is remaining in its off state, the drum is rotated as to expel washing liquid from the laundry.

[0078] Washing, rinsing, and spinning phases can be performed more than once. Also, washing and rinsing phases can comprise, preferably at their respective ends, spinning phases. Also in preferred embodiments with several washing and/or rinsing and/or spinning phases, the heater 10 is in an off-state during these phases. Washing liquid is preferably heated before the respective phase.

[0079] During washing phases and rinsing phases, washing liquid is preferably circulated through the first 20 and or the second recirculation circuit 30. The circulation of washing liquid by the first recirculation circuit 20 improves the wetting of the laundry in the drum. The circulation of washing liquid in the second recirculation circuit 30 improves the mixing of components in the washing liquid. It also enhances a homogenous temperature distribution in the washing liquid. In an end step 236, washing liquid is preferably drained from the tub 3 and the drum is not spinning. The user may thus access the door 8 to remove laundry.

[0080] A second preferred embodiment of the method is shown as a flow chart in FIG. 15 and is preferably conducted in a control unit of the laundry washing machine of FIGs. 1 to 13. In a start step 250, the method starts. Block 250 can as way of example comprise the loading of the drum with laundry, filling at least one laundry treatment agent into drawer 6a, selecting a washing program and pushing a start button on the laundry washing machine 2.

[0081] In a step 252, water is introduced into the tub 3, preferably via at least one of the compartments 6f, 6g, 6h. To this end, water is preferably guided from the fresh water supply /water mains through on-off valve 84 into the water softener device and continues to flow into one of the compartments / the tub 3.

[0082] In a subsequent step 256, a washing phase is performed. During the entire duration of the washing phase, the heater 10 is remaining a switched-off-state. In this way, energy consumption is strongly reduced compared to known washing procedures in which the washing liquid is heated at least partly during the washing phase. At the end of the washing phase in a draining phase 258, washing liquid is drained from the tub 3.

[0083] As applicant has found, the water softening by means of the water softening device 120 allows obtaining a high quality cleaning result of the laundry even though the washing liquid is not heated during the washing phases and/or rinsing and/or spinning phases. The softening of the water therefore allows an higher cleaning efficiency than a non-softener water at the same conditions, i.e. same textiles and same water temperature. A subsequent step 262 is a rinsing phase during which the laundry in the drum is rinsed. During step 262 the heater is remaining in an off-state.

[0084] During washing phases and rinsing phases, washing liquid is preferably circulated through the first and or the second recirculation circuit. The circulation of washing liquid by the first recirculation circuit 20 improves the wetting of the laundry in the drum. The circulation of washing liquid in the second recirculation circuit 30 improves the mixing of components in the washing liquid. It also enhances a homogenous temperature distribution in the washing liquid.

[0085] In a subsequent step 264, water is preferably again drained from the tub 3. In a subsequent spinning phase in a step 270, during which the heater is not activated and is remaining in its off state, the drum is rotated as to expel washing liquid from the laundry.

[0086] Washing, rinsing, and spinning phases can be performed more than once. Also, washing and rinsing phases can comprise, preferably at their respective ends, spinning phases. Also in preferred embodiments with several washing and/or rinsing and/or spinning phases, the heater is off during these phases. Washing liquid is preferably heated before the respective phase.

[0087] In an end step 276, washing liquid is drained from the tub 3 and the drum is not spinning. The user may thus access the door 8 to remove laundry.

[0088] The softening of water via water softening device 120 is preferably performed always when water is introduced into the tub. The invention, however, also encompasses embodiments in which water is softened only during a subset of washing and rinsing phases.

[0089] Preferably, on the user interface 6c, at least one energy-saving program is selectable in which the heater is turned off according to a method described above.

[0090] The invention thus conceived can be subjected to numerous modifications and variants all falling within the scope of the inventive concept. In addition, all details can be replaced by other technically equivalent elements. In practice, all the materials used, as well as the shapes and contingent dimensions, may vary depending on the requirements without departing from the scope of protection of the following claims. The invention especially comprises embodiments in which the heater is never turned on during the whole laundry treatment procedure. It also comprises embodiments in which the heater is turned on outside the washing, rinsing, and spinning phases.

Claims

1. Method for operating a laundry washing machine (1) for treating laundry with a washing liquid, comprising a casing (2) in which a rotatable drum for acceptance of laundry is arranged, further comprising a fresh water supply (5), further comprising a tub (3) in which said drum is arranged, further comprising a heater (10) for heating washing liquid, further comprising a detergent storage container (6) with at least one compartment (6f, 6g, 6h) for collecting a laundry treatment agent, whereby a laundry treatment procedure is performed in which at least one washing phase, at least one rinsing phase, and at least one spinning phase are performed,
characterized in that said heater (10) is always switched off during said washing, rinsing and spinning phases.

2. Method according to claim 1, wherein in at least one of said phases the water coming from said fresh water supply (5) is softened before reaching said tub.

3. Method according to claim 1 or 2, whereby said heater (10) is arranged in a drainage area of said tub (3) / said washing machine (1).

4. Method according to one of the claims 1 to 3, whereby a first recirculation pump (21) is provided for recirculating washing liquid through a first recirculation pipe (23) from a first region at or near the bottom of said tub (3) to a second region of said tub (3), and whereby said first recirculation pump (21) is switched on at least temporarily during said at least one washing phase and/or rinsing phase.

5. Method according to one of the claims 1 to 4, whereby a second recirculating pump (31) is provided for recirculating washing liquid through a second recirculation pipe (32) from a third region at or near the bottom of said tub (3) to a fourth region at or near the bottom of said tub (3), and whereby said second recirculating pump (31) is switched on at least temporarily during said at least one washing phase and / or rinsing phase.

6. Method according to claim 5, whereby said third and said fourth region are essentially the same region.

7. Method according to one of the claims 1 to 6, whereby said washing machine (1) comprises a water softening device (120) which is arranged within said casing (2) and which is fluidly arranged between said fresh water supply (5) and said tub (3) and / or said detergent storage container (6) and whereby in at least one of said phases the water coming from said fresh water supply (5) passes through said water softening device (120) before reaching said detergent storage container (6) / said tub (3).

8. Method according to claim 7, whereby said washing machine (1) comprises a first water circuit by which water from said fresh water supply (5) is transferred to said tub (3) and / or said detergent storage container (6) after passing through said water softening device (120) and comprising a second circuit by which water from said fresh water supply (5) is transferred into said tub (3) and / or said detergent container (6) while bypassing said water softening device (120), whereby in at least one of said phases the water coming from the fresh water supply (5) passes through said first water circuit.

9. Method according to one of the claims 1 to 8, whereby during said laundry treatment procedure, said heater (10) is never turned on.

10. Method for operating a laundry washing machine (1) for treating laundry with a washing liquid, comprising a user interface (6c), whereby on said user interface (6c) of said washing machine (1) a laundry treatment program is selectable, and whereby, if said program is selected and the laundry treatment procedure (1) is switched on, a method according to one of the preceding claims is performed.

11. Laundry washing machine (1) comprising a casing (2) in which a rotatable drum for acceptance of laundry is arranged, further comprising a fresh water supply (5), further comprising a tub (3) in which said drum is arranged, further comprising a heater (10) for heating washing liquid, further comprising a detergent storage container (6) with at least one compartment (6f, 6g, 6h) for collecting a laundry treatment agent, further comprising a control unit in which a method according to one of the previous claims is implemented.

12. Laundry washing machine (1) according to claim 11, whereby said washing machine (1) comprises a water softening device (120) which is arranged within said casing (2) and which is fluidly arranged between said fresh water supply (5) and said tub (3) and / or said detergent storage container (6).

13. Laundry washing machine (1) according to claim 12 comprising a first water circuit by which water from said fresh water supply (5) is transferred to said tub (3) and / or said detergent storage container (6) after passing through said water softening device (120) and comprising a second circuit by which water from said fresh water supply (5) is transferred into said tub (3) and / or said detergent container (6) while bypassing said water softening device (120).

14. Laundry washing machine (1) according to claim 13, whereby said first circuit is configured to channel the softened water selectively into one of said compartments (6f, 6g, 6h) of said detergent storage container (6).

15. Laundry washing machine (1) according to claim 14, whereby said water softening device (120) comprises a container (142) for a water softening agent through which water is guided before it is channelled into a compartment (6f, 6g, 6h) of said detergent storage container (6) and/or guided directly into said tub (3).

Drawing