WO2023110075A1

WO2023110075A1 - Dishwasher and method of operating a dishwasher

Info

Publication number: WO2023110075A1
Application number: PCT/EP2021/085895
Authority: WO
Inventors: Cristina Bertoni; Paolo Posa; Enrico Marson; Stefan Jonsson
Original assignee: Electrolux Appliances Aktiebolag
Priority date: 2021-12-15
Filing date: 2021-12-15
Publication date: 2023-06-22

Abstract

There is described a dishwasher (1) for the cleaning of items comprising at least a cleaning chamber (2) for containing the items to be cleaned within the cleaning chamber (2), one or more distribution arms (3) arranged within the cleaning chamber (1) and each one being configured to rotate around a respective rotation axis (A) and to distribute, in use, a cleaning solution within the cleaning chamber (2), a hydraulic distribution device (4) fluidically connected and/or connectable to the one or more distribution arms (3) and configured to direct the cleaning solution to the one or more distribution arms (3) and a sensing device (30) mechanically connected to an external portion (15) of the hydraulic distribution device (4) and configured to determine at least one vibration profile and/or at least one noise profile for monitoring, in use, a movement of the one or more distribution arms (3).

Description

DISHWASHER AND METHOD OF OPERATING A DISHWASHER

The present invention relates to a dishwasher for the cleaning of items, in particular of kitchenware.

Advantageously, the present invention also relates to a method of operating a dishwasher for cleaning items, in particular for cleaning kitchenware.

There are known dishwashers for the cleaning of items such as plates, knives, forks, spoons, pots, pans and the like.

A typical dishwasher comprises:

- a cleaning chamber containing the items to be cleaned within the cleaning chamber itself;

- a plurality of rotatable distribution arms arranged within the cleaning chamber and configured to distribute a cleaning solution within the cleaning chamber; and

- a hydraulic distribution device configured to direct the cleaning solution to and out of the distribution arms.

It is known that a user distributes the items within the cleaning chamber onto carriages present within the cleaning chamber and the, in use, rotating distribution arms guarantee that the cleaning solution is sprayed onto all the surfaces of the items.

A regular movement of the distribution arms takes place when the washing pump works correctly, that is without cavitation or starvation.

It is furthermore known that the angular speed of the distribution arms may depend on the temperature of the cleaning solution, the operation characteristics of the hydraulic distribution device, the viscosity of the cleaning solution and/or the cleaning solution’s turbidity.

It is further known in the sector that the overall cleaning performance may be affected by a clogging or stacking of one or more of the distribution arms.

Therefore, there is a desire felt in the sector to monitor the movement of the distribution arms, in particular so as to determine the overall efficiency of the operation of the dishwasher.

Thus, a need is felt in the sector to improve the known dishwashers so as to improve the operation efficiency. One aim of the present invention is to provide for a dishwasher coming along with means allowing for a monitoring of the movement of the distribution arms.

Another aim of the present invention is to provide for a method of operating a dishwasher, which guarantees the determination of the movement of the distribution arms.

According to the present invention, there is provided a dishwasher and a method according to the respective independent claims.

Preferred non-limiting embodiments are claimed in the respective dependent claims.

In addition, according to the present invention, there is provided a dishwasher for the cleaning of items comprising at least:

- a cleaning chamber for containing the items within the cleaning chamber;

- one or more distribution arms arranged within the cleaning chamber and each one being configured to rotate around a respective rotation axis and to distribute, in use, a cleaning solution within the cleaning chamber;

- a hydraulic distribution device having a sump for containing at least a portion of the cleaning solution, the hydraulic distribution device being fluidically connected and/or connectable to the one or more distribution arms and configured to direct the cleaning solution to the one or more distribution arms; and

- a sensing device mechanically connected to the hydraulic distribution device and configured to determine at least one vibration profile and/or at least one noise profile over the time, in particular of the hydraulic distribution device, for monitoring, in use, a(n) (angular) movement of the one or more distribution arms.

The hydraulic distribution device comprises an external portion being arranged outside of the cleaning chamber, being in fluidic connection and/or being configured to be in fluidic connection with the one or more distribution arms and being configured to direct the cleaning solution from the sump to and out of the one or more distribution arms.

The sensing device is mechanically connected to the external portion of the hydraulic distribution device. By relying on the at least one vibration profile and/or the at least one noise profile it is possible to indirectly determine the movement characteristics of the one or more distribution arms. This again allows to detect operating conditions of the distributing arms and/or the occurrence of other conditions, such as clogging and/or blocking and/or stacking of the distribution arms.

In particular, independently on the specific position, the sensing device is configured to determine the vibration profile and/or noise profile of a washing pump of the hydraulic distribution device. E.g. this can be achieved by directly connecting the sensing device to the washing pump and/or by connecting the sensing device to a component of the external portion of the hydraulic distribution device (directly or indirectly) connected to the washing pump by means of a respective tubing.

According to some possible embodiments, the dishwasher comprises a control unit operatively coupled to the sensing device and configured to elaborate the at least one vibration profile and/or the at least one noise profile and to determine information about the (angular) movement of the one or more distribution arms from the at least one vibration profile and/or the at least one noise profile.

By having the control unit, it is easily possible to elaborate on the vibration profile and/or the noise profile during operation of the dishwasher.

Preferentially but not necessarily, the control unit may be configured to determine a periodicity within time-series data subsets of the at least one vibration profile and/or the at least one noise profile and/or a respective time-frequency spectrum/spectra of the at least one vibration profile and/or the at least one noise profile, the periodicity being indicative of the movement of the one or more distribution arms.

By determining the periodicity one can easily and reliably obtain the movement characteristics of the distribution arms, such as the rotational speed in radiant per minute (rpm) at a set speed of a washing pump of the hydraulic distribution device.

Preferentially but not necessarily, the control unit is configured to elaborate time-series data subsets of the at least one vibration profile and/or the at least one noise profile through autocorrelation algorithms and/or through Fourier-based and/or Wavelet-based Transformation algorithms to derive respective time-frequency spectrum and/or respective time-frequency spectra.

The Applicant has found that the contribution of the movement of the distribution arm(s) to the time-frequency spectrum/spectra of the at least one vibration profile and/or the at least one noise profile lies in a periodic change of harmonics’ intensity over time. Intensity peaks are located at regular intervals, which are correlated to the actual rotational speed of the distribution arm(s).

Alternatively or in addition, an autocorrelation analysis carried out on the very same windows of the vibration profile and/or the noise profile reveals main peaks that are correlated to the actual rotational speed of the distribution arms.

Preferentially but not necessarily, the periodicity of peaks can be derived by applying a peak-detection algorithm and/or a mean peak-distance algorithm.

The Applicant has also found that time intervals between peaks generally range between 1 up to 20 seconds. Furthermore, the Applicant has found that the time intervals may change depending on the specific hydraulic distribution device (such as a specific washing pump) and/or the characteristics of the distribution arms.

Additionally, the Applicant has found that the amplitude and sharpness of the peaks may change in dependence of the speed regime of a washing pump of the hydraulic distribution device.

According to some preferred non-limiting embodiments, the dishwasher comprises at least two distribution arms. The external portion comprises at least: the sump of the a hydraulic distribution device, a washing pump configured to create a flow of the cleaning solution from the sump along a flow direction to and out of the at least one or more distribution arms; and a flow dividing group configured for selectively diverting the cleaning solution into any one of the distribution arms; a drain pump fluidically connected to the sump and configured to evacuate the cleaning solution from the sump; and one or more ducts fluidically connecting the washing pump to the sump and the flow dividing group and/or at least one auxiliary duct fluidically connecting the drain pump to the sump and/or the flow dividing group comprises a plurality of channels, each one fluidically connected to at least one respective distribution arm.

The sensing device is mechanically connected and/or washing pump and/or the flow dividing group and/or an external surface of the sump and/or the drain pump and/or the ducts and/or the channels and/or the auxiliary ducts.

Preferentially but not necessarily, the most preferred positioning of sensing device is such that the sensing device is mechanically connected to the washing pump and/or the flow dividing group, in particular as providing for the best measurement results.

Preferentially but not necessarily, the most preferred positioning of sensing device is such that the sensing device is mechanically connected to an external surface of the sump or in another preferred embodiment the sensing device is mechanically connected to a casing supporting another sensor for example a turbidity sensor, wherein the casing is mechanically connected to the sump.

Preferentially but not necessarily, the control unit is configured to extract and filter time-series data windows of the at least one vibration profile and/or the at least one noise profile corresponding to speed regimes of the washing pump and/or of a length in time in dependence of operation settings of the flow dividing group so as to generate time-series data subsets.

Preferentially but not necessarily, the washing pump comprises a first electronic control group, in particular having a first electronic board, configured to control operation of the washing pump and the flow dividing group comprises a second electronic control group, in particular having a second electronic board, configured to control operation of the flow dividing group. The sensing device is mechanically connected to the first electronic control group, in particular the first electronic board, and/or the second electronic control group, in particular the second electronic board.

By mechanically connecting the sensing device to the washing pump and/or the flow dividing group, in particular to the first electronic control group and/or the second electronic control group, one easily obtains the coupling of the sensing device to the external portion. Preferentially but not necessarily, the washing pump comprises a casing and the sensing device is mechanically connected to the casing; and/or the flow dividing group comprises a respective housing and the sensing device is mechanically connected to the housing of the flow dividing group; and/or the drain pump comprises a respective housing and the sensing device is mechanically connected to the housing of the drain pump.

Preferentially but not necessarily, the washing pump and/or the drain pump is configured to be operated in dependence of the at least one vibration profile and/or the at least one noise profile determined, in use, by the sensing device.

In this manner, it is possible to modulate operation of the washing pump and/or the drain pump in dependence of the state of the distribution arms in order to determine a desired movement of the distribution arms.

According to some preferred non-limiting embodiment, the sensing device comprises at least one vibration sensor and/or one acoustic sensor mechanically connected to the hydraulic distribution device.

These sensors allow to determine respectively the at least one vibration profile and/or the at least one noise profile.

Preferentially but not necessarily, the vibration sensor comprises an accelerometer and/or the acoustic sensor comprises a microphone.

The accelerometer allows to determine the at least one vibration profile and/or the microphone allows to determine the at least one noise profile.

According to some preferred non-limiting embodiments, the sensing device comprises at least one vibroacoustic sensor coupled to the hydraulic distribution device.

The vibroacoustic sensor allows to determine both the at least one vibration profile and the at least one noise profile.

In addition, according to the present invention, there is provided a method of operating the dishwasher for the cleaning of items.

The method comprises at least the steps of:

- distributing the cleaning solution within the cleaning chamber; - determining at least one vibration profile and/or at least one noise profile by means of the sensing device; and

- monitoring a movement of the one or more distribution arms based on the at least one vibration profile and/or the at least one noise profile.

By relying on the at least one noise profile and/or the at least one vibration profile it is possible to indirectly determine the movement characteristics of the one or more distribution arms. This again allows to detect the occurrence of e.g. clogging and/or blocking and/or stacking of the distribution arms and/or other operating conditions of the distributing arms.

According to some preferred non-limiting embodiments, the method of operating the dishwasher also comprises a step of elaborating, during which at least a respective time-frequency spectrum and/or an autocorrelation profile of the at least one vibration profile and/or the at least one noise profile is obtained.

By determining the time-frequency spectrum/spectra it is possible to analyse the vibration characteristics and/or noise characteristics in the frequency domain over the time.

Alternatively or in addition, time-series data windows may be extracted from each vibration profile and/or each noise profile and are processed through filtering and an autocorrelation followed by mean-peak distance detection so to assess periodicity patterns associated to the time-series data windows in the time domain.

Preferentially, but not necessarily, during the step of elaborating a respective periodicity from time-series data subsets of the at least one vibration profile and/or the at least one noise profile and/or a respective time-frequency spectrum/spectra of the at least one vibration profile and/or the at least one noise profile, the periodicity being indicative of the movement of the one or more distribution arms.

By determining the periodicity it is possible to obtain information about the movement characteristics of the distribution arms.

Preferentially but not necessarily, during the step of elaborating a respective periodicity is determined from time-series data subsets of the at least one vibration profile and/or the at least one noise profile and/or a respective time-frequency spectrum/spectra of the at least one vibration profile and/or the at least one noise profile, the periodicity being indicative of the movement of the one or more distribution arms.

According to some preferred non-limiting embodiments, the method of operating the dishwasher may also comprise the step of controlling a washing pump and/or the hydraulic distribution device, during which the washing pump is controlled in dependence of the (annular) movement characteristics of the distribution arms as determined during the step of monitoring.

A non-limiting embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

- Figure 1 is a perspective view of a dishwasher according to the present invention, with parts removed for clarity;

- Figure 2 is a perspective view of some details of the dishwasher of Figure 1, with parts removed for clarity;

- Figure 3 is a bottom view of some other details of the dishwasher of Figure 1, with parts removed for clarity;

- Figure 4 is a perspective and partial-section view of some portions of the dishwasher of Figure 1, with parts removed for clarity;

- Figure 5 is a perspective view of a further detail of the dishwasher of Figure 1, with parts removed for clarity;

- Figure 6 is a perspective view of an even other detail of the dishwasher of Figure 1, with parts removed for clarity; and

- Figure 7 is another perspective view of some further details of the dishwasher of Figure 1, with parts removed for clarity.

With reference to Figure 1, number 1 indicates as a whole a dishwasher for the cleaning of (household and/or kitchen) items, in particular of kitchenware such as plates, pots, cups, knives, spoons, forks, pans, bowls and the like.

With particular reference to Figures 1 and 2, dishwasher 1 comprises at least:

- a cleaning chamber 2 for containing the items and for allowing the cleaning of the items within cleaning chamber 2, in particular by means of a cleaning solution; - one or more distribution arms 3, in particular at least one, in the specific embodiment disclosed three, arranged within cleaning chamber 2 and each one being configured to rotate around a respective rotation axis A and to distribute, in use, the cleaning solution within cleaning chamber 2; and

- a hydraulic distribution device 4 fluidically connected and/or connectable to distribution arms 3 and configured to direct the cleaning solution to (and out of) distribution arms 3.

Preferentially, the cleaning solution may comprise water only or may comprise water and at least one active cleaning agent (such as a detergent). The cleaning solution may also comprise other components such as food residues present on the items prior to the cleaning and others.

Additionally, the cleaning solution may be substituted and/or exchanged during operation of dishwasher 1.

Furthermore, the composition of the cleaning solution may vary during operation of dishwasher 1.

Moreover, distribution arms 3 may be designed to spray while rotating, in use, around the respective rotation axes A the cleaning solution onto the items.

Preferentially, dishwasher 1 may comprise a control unit (not shown) configured to control operation of dishwasher 1 itself.

Moreover, dishwasher 1, in particular hydraulic distribution device 4, may comprise a sump 5 for containing at least portion of the cleaning solution and/or to receive fresh water and/or a fresh cleaning solution and/or active cleaning agents and/or used cleaning solution. In particular, sump 5 is also configured to collect the cleaning solution being introduced into cleaning chamber 2 by distribution arms 3. Even more particular, a collection reservoir of sump 5 is arranged in a bottom portion of cleaning chamber 2 so as to collect the cleaning solution present within cleaning chamber 2 by means of gravity.

Furthermore, hydraulic distribution device 4 may define a closed flow circuit for the cleaning solution.

Additionally, dishwasher 1 may comprise a supply unit 6 for supplying fresh water and/or a fresh cleaning solution to sump 5 and/or into cleaning chamber 2. In particular, supply unit 6 is fluidically connected to sump 5 so as to direct the fresh water and/or the fresh cleaning solution into sump 5.

According to some possible embodiments, dishwasher 1 could also comprise an active cleaning agent supply group (not shown) configured to supply the active cleaning agent into sump 5 and/or to the fresh water supplied by supply unit 6.

Moreover, dishwasher 1, in particular hydraulic distribution device 4, may comprise a drain pump 7 fluidically connected to sump 5, in particular by means of a at least one auxiliary duct 12, and configured to evacuate the (dirty) cleaning solution from sump 5 (and away from the above-mentioned closed flow circuit).

Furthermore, dishwasher 1 may comprise a control interface designed to allow a user to control operation of dishwasher 1, in particular by setting one or more operation parameters of dishwasher 1 and/or to at least power on dishwasher 1.

Additionally, dishwasher 1 may also comprise one or more carriers 9 arranged and/or arrangeable within cleaning chamber 2 and designed to hold the items to be cleaned (within inner chamber 2). In particular, carriers 9 are displaced from one another so as to distribute, in use, the items within cleaning chamber 2.

In more detail and with particular reference to Figure 1, dishwasher 1 comprises a plurality of walls 10 delimiting at least cleaning chamber 2. Preferentially, walls 10 are positioned such to also define an auxiliary space 11 fluidically separated from cleaning chamber 2 and designed to house at least portions of hydraulic distribution device 4 and in particular also of supply unit 6 and drain pump 7. In particular, auxiliary space 11 is arranged below cleaning chamber 2.

Moreover, dishwasher 1 may comprise a door (not shown) moveable between a closed and open position at which the door respectively closes and opens cleaning chamber 2. During operation of dishwasher 1 (i.e. during a cleaning) the door is kept in the closed position.

Preferentially, the door may be angularly moveable around a hinge axis so as to control the door between the closed position and the open position.

With particular reference to Figures 2 to 7, hydraulic distribution device 4 comprises an external portion 15 arranged outside of cleaning chamber 2, in particular within auxiliary space 11, being in fluidic connection and/or being configured to be in fluidic connection with the one or more distribution arms 3 and being configured to direct the cleaning solution (along a flow direction) from sump 5, in particular the collection reservoir, to and out of the one or more distribution arms 3.

Additionally and with particular reference to Figure 2, hydraulic distribution device 4 may comprise a plurality of flow tubes 16, each one fluidically connected to external portion 15 and to at least one distribution arm 3 and configured to deliver the cleaning solution to the respective distribution arm 3. In particular, each flow tube 16 rotatably carries the respective distribution arm 3.

Moreover, each flow tube 16 is arranged within cleaning chamber 2 and at distinct positions, so as to position distribution arms 3 at respective and distinct positions.

According to the non-limiting specific embodiment shown, a first flow tube 16 is arranged within an upper portion of cleaning chamber 2, a second flow tube 16 is arranged within the bottom portion of cleaning chamber 2 and a third flow tube 16 is interposed between the first and second flow tube 16.

According to the non-limiting specific embodiment disclosed, one of the distribution arms 3, in particular the distribution arm 3 being arranged in a bottom portion of cleaning chamber 2, comprises a main distribution arm 13 rotatable around the rotation axis A and an auxiliary distribution arm 14 rotatably carried by main distribution arm 13. In more detail, auxiliary distribution arm 14 is configured to execute a relative rotation with respect to main distribution arm 13 around a rotation axis B. In particular, main distribution arm 13 and auxiliary distribution arm 14 define a satellite distribution arm system.

Moreover, hydraulic distribution device 4 may also comprise a delivery tube 17 carrying one or more flow tubes 16, in particular two, even more particular first flow tube 16 and third flow tube 16. Additionally, delivery tube 17 may be fluidically connected to hydraulic distribution device 4 and the respective distribution arms 3. In particular, delivery tube 17 may fluidically connect the respective distribution arms 3 with hydraulic distribution device 4.

Preferentially, delivery tube 17 may be arranged within cleaning chamber 2 and may comprise a first portion, in particular having a substantially horizontal orientation, and a second portion being transversally, in particular perpendicularly, arranged with respect to the first portion, and in particular having a substantially vertical orientation. In particular, each one of the first portion and the second portion may be arranged adjacent to one respective wall 10. According to the non-limiting embodiment shown, the second portion carries respective flow tubes 16, in particular the first flow tube 16 and the third flow tube 16.

In further detail, in use, the composition of reactive forces at the respective rotation axes A of the respective distribution arms 3 along the respective rotational movement is transmitted through delivery tube 17 and/or flow tubes 16 to external portion 15.

In further detail, the respective distributing arms 3 may be arranged downstream from the respective flow tube 16 and the respective flow tube 16 may be arranged downstream from external portion 15 with respect to the flow direction of the cleaning solution.

In even more detail, delivery tube 17 may be arranged downstream from external portion 15, (first and third) flow tubes 16 may be arranged downstream from delivery tube 17 and the respective distributing arms 3 may be arranged downstream from the respective flow tube 16 with respect to the flow direction of the cleaning solution.

In more detail and with particular reference to Figures 2 to 7, hydraulic distribution device 4, in particular external portion 15, may comprise at least:

- a washing pump 18 configured to create the flow of the cleaning solution from sump 5 along the flow direction to and out of the at least one or more distribution arms 3; and

- a flow dividing group 19 configured to divide the flow of the cleaning solution so as to selectively direct a desired (variable) portion of the flow of the cleaning solution to each one of the distribution arms 3. Moreover, external portion 15 may also comprise an external surface 27 of sump 5 (while collection reservoir of sump 5 may be arranged within cleaning chamber 2 and/or may define a portion of cleaning chamber 2).

More specifically, washing pump 18 and flow dividing group 19 may be fluidically connected to one another and flow dividing group 19 may be arranged downstream from washing pump 18 along the flow direction. In particular, in use, washing pump 18 may direct the cleaning solution from sump 5, in particular the collection reservoir, to flow dividing group 19 and flow dividing group 19 may direct the respective portions of the cleaning solution to the respective distribution arms 3.

According to the specific non-limiting embodiment shown, flow dividing group 19 may be configured to direct the respective portion of the cleaning solution into delivery tube 17 and to direct the respective portion of the cleaning solution into the second flow tube 16 with respect to the flow direction. In other words, flow dividing group 19 may be arranged upstream from second flow tube 16 and delivery tube 17.

More specifically, washing pump 18 may comprise a first electronic control group, in particular having a first electronic board, configured to control operation of washing pump 18 and flow dividing group 19 may comprise a second electronic control group, in particular having a second electronic board, configured to control operation of flow dividing group 19.

Preferentially, the first electronic control group and the second electronic control group may be operatively connected (by means of wiring or wirelessly) to the control unit, in particular so as to receive control signals from the control unit and/or to send signals to the control unit.

Even more specifically and with particular reference to Figures 3, 6 and 7, washing pump 18 may comprise a casing 20, in particular carrying internal and external flow ducts 21 (of washing pump 18). In particular, ducts 21 may establish a fluidic connection to sump 5, in particular the collection reservoir, and flow dividing group 19. In particular, casing 20 may comprise first portions, which carry internal flow ducts 21 and second portions connected to the first portion. Even more particular, the second portions are not in contact in any manner with the cleaning solution.

Furthermore, washing pump 18 may also comprise at least one pumping element (not shown) for generating the pumping force.

In particular, the first electronic control group may be mechanically connected to casing 20 and/or may be arranged within casing 20.

Even more specifically and with particular reference to Figures 3 to 5, flow dividing group 19 may be configured to divide the flow of the cleaning solution arriving from washing pump 18 into at least a first flow and a second flow for generating the respective portions of the cleaning solution.

Moreover, flow dividing group 19 may comprise a housing 22 carrying at least:

- one inlet channel configured to receive the cleaning solution from washing pump 18;

- at least two outlet channels 23 (of flow dividing group 19), in particular each one fluidically connected to at least one distribution arm 3; and

- a control element 24 (of flow dividing group 19) being operatively coupled to the second electronic control group and configured to selectively control the portions of the cleaning solution to be delivered to the respective distribution arms 3. In particular, control element 24 may be designed to selectively control the portion of the cleaning solution entering one or the other outlet channel 23.

In particular, the second electronic control group may be configured to control operation of control element 24.

In even more detail, one outlet channel 23 may be fluidically connected to delivery tube 17 and the other one to second flow tube 16.

Preferentially, the second electronic control group may be connected to and/or arranged within housing 22.

Furthermore, drain pump 7 may comprise a respective housing 25.

Moreover, operation of washing pump 18 determines, in use, the rotation of distribution arms 3 around the respective rotation axes A. In particular, by modulation of the pumping force and/or the speed of washing pump 18 it is possible to modulate the angular speed of distribution arms 3 around the respective rotation axes A. According to some possible non-limiting embodiments, distribution arms 3 may be displaced from one another, in particular being arranged on different height levels within cleaning chamber 2. In particular, one distribution arm 3 is arranged at the bottom portion, another one at the top portion and a third one is interposed between the other two distribution arms 3.

Preferentially, each distribution arm 3 may extend along a respective longitudinal axis, in particular perpendicular to the respective rotation axis A.

Preferentially, each distribution arm 3 may comprise a plurality of outlet holes and/or outlet nozzles from which, in use, the cleaning solution exits the respective distribution arm 3.

In particular, auxiliary distribution arm 14 of the distribution arm 3 having main distribution arm 13 and auxiliary distribution arm 14 may carry the respective outlet holes and/or outlet nozzles.

With particular reference to Figures 5, 6 and 7, dishwasher 1 comprises a sensing device 30 mechanically connected to hydraulic distribution device 4, in particular to external portion 15 and configured to determine at least one (timedependent) vibration profile and/or one (time-dependent) noise profile for monitoring, in use, a movement of distribution arms 3.

In particular, the applicant has observed that the vibration profile and/or noise profile is correlated to the movement of distribution arms 3 and, therefore, the vibration profile and/or noise profile is/are indicative of the (angular) movement (characteristics) of distribution arms 3.

Even more particular, the Applicant has observed that the use of only the vibration profile and of only the noise profile already allows determining the movement (characteristics) of distribution arms 3. However, by relying on the combination of the information deducible from both the vibration profile and the noise profile it is possible to improve the overall accuracy and efficacy of the method in the full range of operating conditions.

Furthermore, the Applicant has observed that by monitoring the movement (characteristics) of distribution arms 3 by means of the determined vibration and/or noise profiles, it is possible to detect effects such as clogging and/or blocking and/or stacking of distribution arms 3.

Preferentially, sensing device 30 may be mechanically connected to washing pump 18 and/or to flow dividing device 19 and/or drain pump 7 and/or external surface 27 of sump 5 and/or to one or more ducts 21 and/or to one or more channels 23 and/or auxiliary tube 12.

In more detail, sensing device 30 may comprise one or more sensor groups 31, each one mechanically connected to respective portions of hydraulic distribution device 4, in particular (respective portions of) external portion 15, even more particular washing pump 18 and/or to flow dividing device 19 and/or drain pump 7 and/or external surface 27 of sump 5 and/or to one or more ducts 21 and/or to one ore more channels 23 and/or auxiliary tube 12. In particular, each sensor group 31 may be configured to determine one respective vibration profile and/or one respective noise profile.

In particular, independently on the specific position of sensing device 30 and/or sensing groups 31, sensing device 30 is configured to determine the vibration profile and/or noise profile of washing pump 18.

Additionally, sensing device 30 may comprise further sensor groups 31 connected to other portions of external portion 15.

Alternatively, sensing device 30 may only comprise one sensor group 31 connected to washing pump 18 or to flow dividing device 19 or drain pump 7 or external surface 27 of sump 5 or to one or more ducts 21 or to one or more channels 23 and/or auxiliary tube 12.

In more detail, the one or more sensor groups 31 may be connected to the first electronic control group, in particular the first electronic board, and/or the second electronic control group, in particular the second electronic board, and/or to casing 20 and/or within casing 20 and/or to housing 22 and/or within housing 22 and/or to housing 25 and/or within housing 25.

In further detail, each sensor group 31 may comprise a vibration sensor, such as an accelerometer (e.g. a piezoelectric accelerometer, a micro-machined capacitive accelerometer), and/or an acoustic sensor, such as a microphone (e.g. capacitive-based manufactured by silicon micromachining). In particular, the respective vibration sensor may be configured to determine the respective vibration profile and/or the respective acoustic sensor may be configured to determine the respective noise profile.

Alternatively or in addition, each sensor group 31 may comprise (in particular consist) of a vibroacoustic sensor configured to determine the respective vibration profile and the respective noise profile.

According to some possible non-limiting embodiments, each accelerometer may present a band width of up to 10 kHz.

According to some non-limiting embodiments, sensing device 30, in particular each sensor group 31, may be operatively coupled to the control unit, in particular for sending each vibration profile and/or each noise profile to the control unit.

According to some possible non-limiting embodiments, sensing device 30, in particular each sensor group 31, and the control unit may be operatively connected to one another by wiring or wirelessly.

Preferentially, the control unit may be configured to at least determine information about the movement of distribution arms 3 from the vibration profile(s) and/or the noise profile(s).

In more detail, the control unit may be configured to determine a respective periodicity within time-series data subsets and/or a respective time-frequency spectrum of the noise profile(s) and/or the respective vibration profile(s), the periodicity, in particular of determined intensity peaks, being indicative of the movement of distribution arms 3 and being correlated to the actual rotational speed of distribution arms 3.

In further detail, the Applicant has found that the contribution of the movement of the distribution arm(s) 3 to the time-frequency spectrum/spectra of the at least one vibration profile and/or the at least one noise profile lies in a periodic change of harmonics’ intensity over time. Intensity peaks are located at regular intervals, which are correlated to the actual rotational speed of distribution arm(s) 3.

In even more detail, the control unit is configured to elaborate the respective frequency spectrum(s) in a prefixed frequency interval, , in particular depending on the sensing device 30, in particular the respective sensing group’s 31 working bandwidth. In particular, to reduce calculation times the control unit may be configured to determine the periodicity of the time-frequency spectrum/a within a prefixed frequency interval, in particular where a sharpness of intensity peaks is optimal.

The applicant has observed that the contribution of the movement of distribution arms 3 to the time-frequency spectrum/spectra of each vibration profile and/or each noise profile can be revealed in any fixed frequency interval, in particular up to 10 kHz. Furthermore, it may be possible to rely on sensing device(s) 31 with smaller bandwidth (e.g., up to 5kHz) or subset of data (e.g. by filtering with cut-off frequency at 1 kHz or by downsampling by 10 times which emulates a 10-fold lower sampling rate).

Furthermore, the control unit may be configured to transform the timedependent vibration profile(s) and/or the time-dependent noise profile(s) into respective time-frequency spectrum or time-frequency spectra by means of a Fourierbased transformation or by means of a Wavelet-based Transformation. Alternatively, the control unit may be configured to process the time-dependent vibration profile(s) and/or the time-dependent noise profile(s) data (e.g., using 50 second time-windows corresponding at fixed washing pump 18 speed settings) by filtering (e.g., low-pass band filtering at 1kHz cut-off or high-pass band filter at 2kHz cut-off) and by applying an autocorrelation algorithm followed by mean-peak distance algorithm to identify periodicity.

Moreover, an autocorrelation analysis carried out on the windows of the vibration profile and/or the noise profile may reveal main peaks that are correlated to the actual rotational speed of distribution arm(s) 3.

The Applicant has also found that time intervals between peaks generally range between 1 up to 20 seconds. Furthermore, the Applicant has found that the time intervals may change depending on the specific hydraulic distribution device 4 (such as a specific washing pump 18) and/or the characteristics of distribution arms 3.

According to some possible non-limiting embodiments, the control unit may be configured to extract and filter time-series data windows of the at least one vibration profile and/or the at least one noise profile corresponding to speed regimes of washing pump 18 and/or of a length in time in dependence of operation settings of flow dividing group 19 so as to generate time-series data subsets.

According to some possible non-limiting embodiments, washing pump 18 and/or drain pump 7 may be configured to be operated in dependence of the vibration profile(s) and/or noise profile(s) determined, in use, by sensing device 30.

In more detail, the control unit may be configured to control operation of washing pump 18 and/or drain pump 7in dependence of the vibration profile(s) and/or noise profile(s) determined, in use, by sensing device 30.

In use, dishwasher 1 cleans items, which are arranged in cleaning chamber 3, during one or more cleaning cycles. In particular, the items have been loaded onto carriers 9 prior to the activation of the one or more cleaning cycles.

In particular, operation of dishwasher 1 comprises at least the steps of:

- distributing the cleaning solution within cleaning chamber 2;

- determining at least one vibration profile and/or at least one noise profile by means of sensing device 30; and

- monitoring a movement of the one or more distribution arms 3 based on the at least one vibration profile and/or the at least one noise profile, in particular for obtaining the respective (angular) movement characteristics of distribution arms 3.

Moreover, operation of dishwasher 1 may also comprise the steps of:

- feeding fresh water and/or fresh cleaning solution into sump 5, in particular by operating supply unit 6;

- evacuating sump 5 so as to remove used (and dirty) cleaning solution from sump 5, in particular by operating drain pump 7; and

- introducing an active cleaning agent to the fresh water and/or the fresh cleaning solution.

In more detail, during the step of distributing, hydraulic distribution device 4 may direct the cleaning solution to and out of distributing arms 3.

Furthermore, during the step of distributing, distributing arms 3 may rotate around their respective rotation axes A as a result of the cleaning solution being directed by hydraulic distribution device 4 to and out of distribution arms 3.

In more detail, during the step of distributing, washing pump 18 may direct the cleaning solution from sump 5 to and out of distributing arms 3. Additionally, flow dividing group 19 may divide the cleaning solution such that the respective portions of the cleaning solution are directed to distribution arms 3.

In more detail, during the step of determining, sensing device 30, in particular sensing groups 31, may determine the respective (time-dependent) vibration profile(s) and/or (time-dependent) noise profile(s) associated to hydraulic distribution device 4, in particular to external portion 15.

Additionally, operation of dishwasher 1 may also comprise the step of elaborating, during which the control unit elaborates each vibration profile and/or each noise profile. In particular, the control unit may elaborate each vibration profile and/or each noise profile such to obtain the information characteristic of the (angular) movement of distribution arms 3.

In more detail, during the step of elaborating, the control unit may obtain a respective time-frequency spectrum for each vibration profile and/or each noise profile.

In particular, during the step of elaborating, the control unit may obtain the respective time-frequency spectrum for each vibration profile and/or each noise profile by means of a Fourier-based transformation or a Wavelet-based Transformation.

More specifically, during the step of elaborating, each time-frequency spectrum may be analysed (by the control unit) such to obtain a respective periodicity being indicative of the movement of distribution arms 3.

Alternatively, during the step of elaborating, the control unit may process timeseries data windows extracted from each vibration profile and/or each noise profile through filtering (e.g., low-pass and/or high-pass) and autocorrelation algorithms followed by mean-peak distance detection so to assess periodicity patterns associated to the time-series data windows.

According to some non-limiting embodiments, operation of dishwasher 1 may also comprise the step of controlling washing pump 18, during which operation of washing pump 18 and/or drain pump 7 is controlled in dependence of the (annular) movement characteristics of distribution arms 3 determined during the step of monitoring.

Preferentially, operation of dishwasher 1 may also comprise a step of repeating during which at least the steps of distributing, determining and monitoring, in particular also the step of elaborating, are repeated. Clearly, changes may be made to dishwasher 1 and/or the method according to the present invention without, however, departing from the scope of the present invention.

Claims

1.- Dishwasher (1) for the cleaning of items comprising at least:

- a cleaning chamber (2) for containing the items to be cleaned within the cleaning chamber (2);

- one or more distribution arms (3) arranged within the cleaning chamber (1) and each one being configured to rotate around a respective rotation axis (A) and to distribute, in use, a cleaning solution within the cleaning chamber (2);

- a hydraulic distribution device (4) having a sump (5) for containing at least a portion of the cleaning solution, the hydraulic distribution device (4) being fluidically connected and/or connectable to the one or more distribution arms (3) and configured to direct the cleaning solution to the one or more distribution arms (3); and

- a sensing device (30) mechanically connected to the hydraulic distribution device (4) and configured to determine at least one vibration profile and/or at least one noise profile for monitoring, in use, a movement of the one or more distribution arms (3); wherein the hydraulic distribution device (4) comprises an external portion (15) being arranged outside of the cleaning chamber (3), being in fluidic connection and/or being configured to be in fluidic connection with the one or more distribution arms (3) and being configured to direct the cleaning solution from the sump (5) to and out of the one or more distribution arms (3); wherein the sensing device (30) is mechanically connected to the external portion (15) of the hydraulic distribution device (4).

2.- Dishwasher according to claim 1, further comprising a control unit operatively coupled to the sensing device (30) and configured to elaborate the at least one vibration profile and/or the at least one noise profile and to determine information about the movement of the one or more distribution arms (3) from the vibration profile and/or the noise profile.

3.- Dishwasher according to claim 2, wherein the control unit is configured to determine a periodicity within time-series data subsets of the at least one vibration profile and/or the at least one noise profile and/or a respective time-frequency

22 spectrum/spectra of the at least one vibration profile and/or the at least one noise profile, the periodicity being indicative of the movement of the one or more distribution arms (3).

4. Dishwasher according to claim 2 or 3, wherein the control unit is configured to elaborate time-series data subsets of the at least one vibration profile and/or the at least one noise profile through autocorrelation algorithms and/or through Fourierbased and/or Wavelet-based Transformation algorithms to derive respective timefrequency spectrum and/or respective time-frequency spectra.

5.- Dishwasher according to any one of the preceding claims, comprising at least one distribution arms (3); wherein the external portion (15) comprises at least:

- a washing pump (18) configured to create a flow of the cleaning solution from the sump (5) along a flow direction to and out of the at least one or more distribution arms (3);

- a flow dividing group (19) configured for selectively diverting the cleaning solution into any one of the distribution arms (3);

- a drain pump (7) fluidically connected to the sump (5) and configured to evacuate the cleaning solution from the sump (5); and

- one or more ducts (21) fluidically connecting the washing pump (18) to the sump (5) and/or at least one auxiliary duct (12) fluidically connecting the drain pump (7) to the sump (5) and/or the flow dividing group (19) comprises a plurality of channels (23), each one fluidically connected to at least one respective distribution arm (3); wherein the sensing device (30) is mechanically connected to the washing pump (18) and/or the flow dividing group (19) and/or an external surface of the sump (5) and/or the drain pump (7) and/or the ducts (21) and/or the channels (23) and/or the auxiliary ducts ().

6.- Dishwasher according to claim 5 and 2 or 3, wherein the control unit is configured to extract and filter time-series data windows of the at least one vibration profile and/or the at least one noise profile corresponding to speed regimes of the washing pump (18) and/or of a length in time in dependence of operation settings of the flow dividing group (19) so as to generate time-series data subsets.

7.- Dishwasher according to claim 5 or 6, wherein the washing pump (18) comprises a first electronic control group configured to control operation of the washing pump (18) and the sensing device (30) is mechanically connected to the first electronic control group; and/or the flow dividing group (19) comprises a second electronic control group configured to control operation of the flow dividing group (19) and the sensing device (30) is mechanically connected to the second electronic control group.

8.- Dishwasher according to any one of claims 5 to 7, wherein the washing pump (18) comprises a casing (20) and the sensing device (30) is mechanically connected to the casing (20); and/or wherein the flow dividing group (19) comprises a respective housing (22) and the sensing device (30) is mechanically connected to the housing (22); and/or wherein the drain pump (7) comprises a respective housing (25) and the sensing device (30) is mechanically connected to the housing (25) of the drain pump (7).

9.- Dishwasher according to any one of claims 5 to 8, wherein the washing pump (18) and/or the drain pump (7) is configured to be operated in dependence of the at least one vibration profile and/or the at least one noise profile determined, in use, by the sensing device (30).

10.- Dishwasher according to any one of the preceding claims, wherein the sensing device (30) comprises at least one vibration sensor and/or one acoustic sensor mechanically connected to the hydraulic distribution device (4).

11.- Dishwasher according to claim 10, wherein the vibration sensor comprises an accelerometer and/or the acoustic sensor comprises a microphone.

12.- Dishwasher according to any one of the preceding claims, wherein the sensing device (30) comprises at least one vibroacoustic sensor mechanically connected to the hydraulic distribution device (4).

13.- Method of operating a dishwasher (1) according to any one of the preceding claims, comprising at least the steps of: - distributing the cleaning solution within the cleaning chamber (3); and

- determining at least one vibration profile and/or at least one noise profile by means of the sensing device (30); and

- monitoring a movement of the one or more distribution arms (3) based on the at least one vibration profile and/or the at least one noise profile.

14.- Method according to claim 13, further comprising a step of elaborating, during which at least a respective time-frequency spectrum and/or an autocorrelation profile of the at least one vibration profile and/or the at least one noise profile is obtained; and/or time-series data windows are extracted from each vibration profile and/or each noise profile and are processed through filtering and an autocorrelation followed by mean-peak distance detection so as to assess periodicity patterns associated to the timeseries data windows.

15.- Method according to claim 13 or 14, wherein during the step of elaborating a respective periodicity is determined from time-series data subsets of the at least one vibration profile and/or the at least one noise profile and/or a respective time-frequency spectrum/spectra of the at least one vibration profile and/or the at least one noise profile, the periodicity being indicative of the movement of the one or more distribution arms (3).

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