Electric appliance comprising an acoustic panel and method of assembling such electric appliance

Abstract

An acoustic panel (1) for an electric appliance (2) with a tank (21) is specified, wherein - the acoustic panel comprises an inner plate (11) facing the tank (21) and an outer plate facing away from the tank (21), - a volume (13) between the inner plate (11) and the outer plate (12) is filled with a filling material (14), - the acoustic panel (1) is configured to be mounted to at least one reinforcement bar (22) on an outer wall ( 210) of the tank (21) wherein the inner plate of the acoustic panel (1) is located closer to the outer wall (210) of the tank (21) than a surface of the reinforcement bar (22) that faces away from the tank (21), and - the acoustic panel (1) comprises a frequency tuning element (4) configured to tune a specific acoustic dampening frequency band of the acoustic panel (1). Further, an electric appliance (2) and a method of assembling an electric appliance (2) are specified.

Description

[0001] P2024,0667 WO N / P240022WO01 September19,2025 -1 - DescriptionAcoustic panel, electric appliance and method of as semblingan electricapplianceThe present disclosure relates to an acoustic panel , anelectric appliance, and to a method of assembling a n electricappliance.Electric appliances such as those used in energy di stributionnetworksmayproduce noise during operation.Embodiments of the disclosure relate to a way to da mpen noiseduring operation ofan electricappliance.According to an embodiment of an acoustic panel, th e acousticpanelisconfigured foran electricappliance with a tank,wherein the acoustic panel comprises an inner plate facingthe tank and an outer plate facing away from the ta nk. Avolume between the innerplate and the outerplate isfilledwith a filling material. The acoustic panel compris es afrequency tuning element configured to tune a speci ficacoustic dampening frequency band of the acoustic p anel. Forexample, the acoustic panel is configured to be mou nted to atleast one reinforcement bar on an outer wall of the tankwherein the inner plate of the acoustic panel is lo catedcloser to the outer wall of the tank than a surface of thereinforcementbarthatfacesawayfrom the tank.The noise reduction may result from the dissipation ofacoustic energy in the volume, in particular in the fillingmaterialasthe filling materialmaybe stimulated to vibrateby the inner plate and / or the outer plate. These pl ates may P2024,0667 WO N / P240022WO01 September19,2025 -2 -vibrate with low order forms and therefore with hig h acousticefficiency. In particular, the vibration of the inn er plateand / or the outer plate may result from pressure wav es in theair between the outer wall of the tank and the acou sticpanel.By means of the frequency tuning element, the acous tic panelmay configured in such a way that it dampens a spec ificacoustic frequency band of a particular electric ap pliance.In particular, the vibration modes may be changed i n atargeted manner by means of the frequency tuning el ement, sothat the acoustic panel has the highest noise reduc tion in apredetermined frequency range. Thus, during its pro ductionthe acoustic panel may be specifically adapted by m eans ofthe frequencytuning elementto efficientlydampen noise in afrequency band where the noise emission of the elec tricappliance during operation is particularly high. Fo r example,typical dominant noise frequencies are around 100 H z, 120 Hz,300 Hz,or400 Hz. Further,parametersaffecting the stiffnessofthe acousticpanel and / or parameters of the filling material may be usedto appropriately tune the dampening properties of t heacousticpanel.In particular, a high dampening efficiency can be o btainedwith acoustic panels that have a low weight compare d toconventionalsolutions. The acousticpanelmaybe configured such thatthereinforcement bars of the tank may be used to mount theacoustic panel. In contrast to conventional solutio ns, an P2024,0667 WO N / P240022WO01 September19,2025 -3 -additional supporting construction spaced apart fro m the tankcan be dispensed with.Further, the addition of the acoustic panel does no t or atleast not significantly increase the overall dimens ions ofthe electricappliance.Further, access to the electric appliance, for inst ance formaintenance purposes is facilitated compared to sol utionswhere a supporting structure is mounted to the tank or / andto the ground and extends around the tank at a dist ance fromthe tank.For example, the electric appliance comprises a liq uid-immersed, in particular an oil-immersed power devic e. Thus,the tankreceivesthe powerdevice and the liquid.For example, the power device comprises at least on e of: atransformer, a phase shifter, a reactor, an inducto r.For example, the electric appliance is configured t o be usedin an energydistribution network.For example, the inner plate and the outer plate of theacousticpanelextend in parallelorsubstantially in parallelto one another.Forexample,the acoustic panelcomprises side walls extending obliquely or perpend icularlywith respect to the inner plate and / or to the outer plate.The inner plate, the outer plate and the side walls takentogether may define the volume.For example, the inner plate and / or the outer plate comprisesor consists of a metal such as carbon steel, stainl ess steel P2024,0667 WO N / P240022WO01 September19,2025 -4 -or aluminum. Alternatively or in addition, at least one ofthe innerplate orthe outerplate maycomprise or consistof a plasticsmaterial.The reinforcement bars are not limited with respect to theircross-section.Forexample,the reinforcementbars mayhave aU-shaped, C-shaped, L-shaped, I-shaped, T-shaped or arectangularcross-section.Further, the electric appliance may comprise reinfo rcementbars that differ from one another with respect to a shapeand / or the dimensions of the cross-section. For exa mple, atleast some of the reinforcement bars are arranged v erticallyor at least substantially vertically in space. Alte rnativelyor in addition, horizontal reinforcement bars may b eprovided. Alternatively or in addition, oblique rei nforcementbars may be provided, for instance diagonal reinfor cementbars.For example, the acoustic panel is configured to be mountedbetween reinforcementbarsofthe tankarranged on the outerwall of the tank, in particular between two directl y adjacentreinforcementbars.Thus,a gap between adjacentreinforcement bars may be at least partly filled wi th theacousticpanel.Alternatively, the acoustic panel may be mounted on ly on oneside ofthe acousticpanelto a reinforcementbar. Forexample, this may apply at an edge or a corner of t he tank.In this case, an additional construction may be use d to mountthe acousticpanelon the otherside. P2024,0667 WO N / P240022WO01 September19,2025 -5 -According to a further embodiment of the acoustic p anel, thefrequency tuning element is located within the volu me. Thus,the frequencytuning elementdoesnotincrease the size ofthe acoustic panel. For example, the frequency tuni ng elementis arranged on a side of the outer plate that faces the innerplate or on a side of the inner plate that faces th e outerplate.According to a further embodiment of the acoustic p anel, thefrequency tuning element comprises a concentrated m ass. Thus,the concentrated mass may act as a frequency tuning elementthatchangesthe vibration modesand tunesthem to apredetermined frequency range by locally increasing the massof the acoustic panel in a targeted manner. For exa mple, adensityofthe concentrated massisatleastby50 % largerthan a density of the filling material. For example , theconcentrated mass comprises a metal. In particular, the massand / or the position of the concentrated mass and / or thenumber of concentrated masses may be used to approp riatelychange the vibration modes.For example, a lateral extent of the concentrated m ass is atmost 50 % of a lateral extent of the acoustic panel when seenalong the same direction. The term lateral extent i nparticularmeansthe extentalong a direction that extendsinparallel to the inner plate and / or the outer plate. Inparticular,the lateralextentofthe concentrated massissmall compared to a width of the acoustic panel. If theacoustic panel has a substantially rectangular shap e, thewidth refers to the lateral extent along the shorte r edge.According to a further embodiment of the acoustic p anel, amass of the concentrated mass is in a range from 0. 2 kg to 10 P2024,0667 WO N / P240022WO01 September19,2025 -6 -kg. It has turned out that concentrated masses in t his rangeare particularlysuitable to specificallytune the acoustic dampening frequencyband ofthe acousticpanel. Forexample,the acousticpanelcomprisesatleast one oratleast two and / or at most 20 or at most 10 concentra ted massesasfrequencytuning elements.According to a further embodiment of the acoustic p anel, thefrequency tuning element comprises a stiffener conf igured tostiffen the innerplate orthe outerplate.Ithas been foundthat the stiffness of the acoustic panel significan tlyaffects the acoustic dampening properties. Thus, th estiffener may act as a frequency tuning element tha t changesthe vibration modes of the acoustic panel due to th eincreased stiffness of the acoustic panel. In parti cular, thestiffenermaybe used to increase the stiffnessof theacoustic panel without having to increase the thick ness ofthe innerplate and / orthe outerplate.Thishelps to keep the weightofthe acousticpanellow.For example, the stiffener is attached to the inner plate orto the outer plate. For example, the stiffener is s pacedapart from the other one of the inner plate and the outerplate. Alternatively, the stiffener may extend from the innerplate to the outerplate atleastin regions.According to a further embodiment of the acoustic p anel, thestiffener extends over at least 70 % of the acousti c panelalong a lateral direction. For example, a lateral e xtent ofthe stiffener is at most 70 % of a width of the aco usticpane. P2024,0667 WO N / P240022WO01 September19,2025 -7 -According to a further embodiment of the acoustic p anel, thestiffener is formed from the same material as the i nner plateor the outer plate. The stiffener may comprise a me tal, forinstance.According to a further embodiment of the acoustic p anel, amaterial of the stiffener is different from a mater ial of theinner plate or the outer plate. The stiffener may c omprise aplasticsmaterial,forinstance.According to a further embodiment of the acoustic p anel, theacoustic panel comprises a mounting region for moun ting theacousticpanel.In particular,the mounting region laterallyprojects beyond the inner plate. For example, the a cousticpanel comprises two mounting regions extending alon g twoopposite edgesofthe acousticpanel.Forexample, themounting region is configured to receive a mechanic alconnectorsuch asa screw ora boltora clamp.For example, the mounting region is formed by a par t of theouter plate that laterally projects beyond the inne r plate.Alternatively or in addition, the mounting region m ay beformed by an extension attached to the outer plate.According to a further embodiment of the acoustic p anel, adensityofthe filling materialisin a range from 0.5 g / cm³to 5 g / cm³. Thus, the filling material has a compar ably highdensity.For example, the filling material may comprise a pl asticsmaterialsuch aspolyvinylchloride (PVC). P2024,0667 WO N / P240022WO01 September19,2025 -8 - Alternativelyorin addition,the filling material maycomprise a granular rubber material such as granula r EPDM(ethylene propylene diene monomer). It has turned o ut that afilling materialhaving a comparablyhigh density, inparticular granular rubber, is suitable to efficien tly dampennoise with frequencies occurring during operation o f electricapplianceswith a powerdevice immersed in a tank.According to a further embodiment of the acoustic p anel, adensityofthe filling materialisin a range from 5 kg / m³to 500 kg / m³.Forexample,mineralwooltypicallyhas a densityin a range from 30 to 200 kg / m³. Alternatively or i n additionthe filling material may comprise an acoustic foam. A fillingmaterial having a low density helps to reduce the w eight ofthe acousticpanel.According to a further embodiment of the acoustic p anel, agrain size of the filling material is in a range fr om 0.1 mmto 5 mm. Granular material with a grain size in thi s rangehas been proven to be particularly efficient for da mpeningnoise in typical emission frequency bands of electr icappliances.However,non-granularfilling material mayalso be used.According to a further embodiment of the acoustic p anel, atleast one of the inner plate or the outer plate has athickness in a range from 2 mm to 6 mm. It has turn ed outthat an efficient noise reduction can be obtained w hile theweight of the acoustic panel can be kept low at the sametime.According to a further embodiment of the acoustic p anel, athicknessofthe acousticpanelisin a range from 10 mm to P2024,0667 WO N / P240022WO01 September19,2025 -9 -300 mm. The thickness refers to the extent of the a cousticpanel in a direction perpendicular to the outer pla te of theacoustic panel. In particular, the thickness of the acousticpanelmaybe used to adaptthe efficiencyofnoise dampeningand / or the spectral response of the acoustic panel.Further, an electric appliance is specified. In par ticular,the electric appliance comprises at least one acous tic panelasdescribed above and a tank.According to an embodiment of the electric applianc e, thetank comprises a plurality of reinforcement bars ar ranged onan outer wall of the tank wherein the acoustic pane l ismounted to at least one of the reinforcement bars w herein theinner plate of the acoustic panel is located closer to theouter wall of the tank than a surface of the reinfo rcementbarthatfacesawayfrom the tank.For example, the acoustic panel may be mounted betw een tworeinforcement bars of the plurality of reinforcemen t bars, inparticular between two directly adjacent reinforcem ent bars.Forexample,the acousticpanelextendsinto a gap betweentwo directly adjacent reinforcement bars in a top v iew ontothe electric appliance. Alternatively or in additio n, anacoustic panel of the electric appliance may be mou nted toonly one of the reinforcement bars as described abo ve.According to a further embodiment of the electric a ppliance,the inner plate is arranged completely within a gap betweentwo adjacentreinforcementbarsin a top view onto theelectric appliance. Thus, the space between the rei nforcementbars can be used, at least in part, for the acousti c panel. P2024,0667 WO N / P240022WO01 September19,2025 -10 -For example, all gaps between two adjacent reinforc ement barsare at least partly filled with one acoustic panel.According to at least one embodiment of the electri cappliance,the acousticpanelcomprisesa mounting regionthat overlaps with one of the reinforcement bars. I nparticular, a sealing and / or damping material may b e arrangedbetween the mounting region and the reinforcement b ar. Thesealing and / or damping material may be used to redu ce atransfer of vibrations of the outer wall of the tan k to theacoustic panel via the mounting region, and / or to s eal aclosed area created between the acoustic panels, th ereinforcement bars, and the outer wall of the tank.For example, the sealing and / or damping material co mprises arubber material or cork rubber. In this area also o therdamping systemscan be used,forexample single or stacked spring washers.According to at least one embodiment of the electri cappliance, a distance between a support structure o f theacoustic panel and the tank is sealed using a seali ng system.For example, the sealing system comprises cork, rub ber oranothersealing material.Forexample,a thickness ofthe sealing system isin a range from 1 mm to 500 mm.According to at least one embodiment of the electri cappliance, a distance between the inner plate of th e acousticpaneland the outerwallofthe tankisin a range from 0 mmto 500 mm. Thus, the inner plate may directly adjoi n theouter wall of the tank. Alternatively, the inner pl ate may bespaced apart from the outer wall of the tank. For e xample, P2024,0667 WO N / P240022WO01 September19,2025 -11 -the distance between the inner plate of the acousti c paneland the outerwallofthe tankisatleast1 mm or atleast 5 mm oratleast10 mm.Further, a method of assembling an electric applian ce isspecified.According to an embodiment of the method, the metho dcomprisesthe stepsofproviding an electricpower device, the step offorming a tankthatextendsaround the electricpower device wherein the tank comprises a plurality ofreinforcement bars arranged on an outer wall of the tank andthe step ofmounting an acousticpanelto atleast one oftheplurality of reinforcement bars wherein the inner p late ofthe acoustic panel is located closer to the outer w all of thetank than a surface of the reinforcement bar that f aces awayfrom the tank. The method steps can be performed in theindicated order.However,thisisnotnecessary.According to a further embodiment of the method, th e step ofmounting the acoustic panel is performed prior to t he step offorming the tank. Thus, the acoustic panel can be p rovided ina pre-assembled mannertogetherwith a partofthe tank.Inconventional approaches, in contrast, the tank is f ormedfirst and the sound panels are attached to a suppor tingstructure thatextendsaround the finished tankat a minimumdistance from the tank which is typically about 500 mm.The method is particularly suitable for the electri cappliance described above.Featuresand advantages describedin connection with the acoustic panel or the electr icappliance can therefore be used forthe method and vice versa. P2024,0667 WO N / P240022WO01 September19,2025 -12 - Featuresdescribed in connection with atleastone embodimentmay be combined with other features described in co nnectionwith other embodiments unless they are contradictor y.The accompanying figuresare included to provide a furtherunderstanding. In the figures, elements of the same structureand / orfunctionalitymaybe referenced bythe same reference signs.Itisto be understood thatthe embodiments shown inthe figures are illustrative representations and ar e notnecessarilydrawn to scale. In the Figures:Figure 1A shows a schematic sectional view of an el ectricappliance with acoustic panels according to an embo diment,Figure 1B shows a schematic side view of an electri cappliance with acoustic panels according to an embo diment,Figure 2A shows a schematic sectional view of an el ectricappliance with acoustic panels according to an embo diment,Figure 2B shows a schematic side view of an electri cappliance with acoustic panels according to an embo diment,Figure 3 shows a perspective sectional view of a de tail of anelectric appliance with an acoustic panel according to anembodiment,Figure 4A shows a perspective view of a detail of a n electricappliance with an acoustic panel according to an em bodiment,Figure 4B showsa sectionalview ofa detailofan electricappliance with an acoustic panel according to an em bodiment, P2024,0667 WO N / P240022WO01 September19,2025 -13 -Figure 5A shows a perspective view of a detail of a n electricappliance with an acoustic panel according to an em bodiment,Figure 5B shows a perspective view of a detail of a n electricappliance with an acoustic panel according to an em bodiment,Figure 6A shows a schematic side view of an electri cappliance with acoustic panels according to an embo diment,Figure 6B shows a further schematic side view of an electricappliance with acoustic panels according to an embo diment,Figure 7 shows a schematic representation of a meth odaccording to an embodiment.While the disclosure is amendable to various modifi cationsand alternative forms,specificsthereofhave been shown byway of example in the figures and will be described indetail.Itshould be understood,however,thatthe intentionis not to limit the disclosure to the particular em bodimentsdescribed. On the contrary, the intention is to cov er allmodifications, equivalents, and alternatives fallin g withinthe scope of the disclosure defined by the appended claims.In the embodiment shown in Figures 1A and 1B, an ac ousticpanel 1 is configured for an electric appliance 2 w ith a tank21. The acoustic panel 1 comprises an inner plate 1 1 facingthe tank21 and an outerplate 12 facing awayfrom the tank 21.A volume 13 between the innerplate 11 and the outer plate 12 isfilled with a filling material14.The acousticpanel 1 is configured to be mounted to at least onereinforcement bar 22 on an outer wall 210 of the ta nk 21. Theinner plate 11 of the acoustic panel 1 is located c loser tothe outer wall 210 of the tank 21 than a surface of thereinforcementbar22 thatfacesawayfrom the tank 21. P2024,0667 WO N / P240022WO01 September19,2025 -14 -The acoustic panel 1 comprises a plurality of frequ encytuning elements 4 configured to tune a specific aco usticdampening frequency band of the acoustic panel 1. I n theembodiment shown in Figures 1A and 1B, the frequenc y tuningelements 4 are formed as concentrated masses 41. Du ringproduction ofthe acousticpanels1,the dampening frequency band ofthe acousticpanel1 maybe adapted to the frequency where the noise emission ofthe electricappliance 2 duringoperation is particularly high. For example, a domi nant noisefrequencymaybe around 100 Hz,120 Hz,300 Hz,or 400 Hz. Exemplarily,the acousticpanel1 comprisesthreeconcentrated masses 41. However, the number of freq uencytuning elements 4 may be varied in wide ranges, for examplein a range from 1 to 20.The frequency tuning elements 4 are arranged in the volume13,so thatthe frequencytuning elements4 do not increase the size ofthe acousticpanels1. A lateralextente1 ofthe concentrated mass41 is small compared to a lateralextentofthe acousticpanel 1 whenseen along the same direction. For example, the lat eralextent e1 of the concentrated mass 41 is at most 50 % of awidth w1 of the acoustic panel 1. Due to their comp arablysmall lateral extent e1, the concentrated masses 41 can bepositioned in regions of the acoustic panel 1 where thefrequencytuning isparticularlyefficient.The concentrated masses 41 may be formed from a mat erialhaving a high density,forexample from a metal. P2024,0667 WO N / P240022WO01 September19,2025 -15 -In a side view, the concentrated masses 41 have a r ectangularcross-section, for instance a square cross-section, but othershapesmay also be used.For example, a mass of the concentrated masses 41 i s in arange from 0.2 kg to 10 kg. The acoustic panel 1 ma y alsocomprise concentrated masses 41 that differ from on e anotherwith respect to the weight and / or the lateral exten t.In the embodiment shown in Figures 1A and 1B, the a cousticpanels1 are each mounted in a gap 221 between two adjacentreinforcement bars 22. Thus, the gap 221 is at leas t partlyfilled with the acoustic panel 1 so that this space can beused fornoise dampening.Different ways for mounting the acoustic panel 1 to thereinforcement bars 22 will be described in connecti on withFigures4A,4B,5A,and 5B.A distance between a support structure of the acous tic panel1 and the tank 21 may be sealed using a sealing sys tem. Forexample,the sealing system comprisescork,rubber oranothersealing material. For example, a thickness of the s ealingsystem is in a range from 1 mm to 500 mm.Unlike the schematicrepresentationsofFigures1A and 1B,the acoustic panel 1 can also be mounted to only on ereinforcementbar22.Forexample,thismaybe the case atanedge or a corner of the tank 2. Here, the side of t heacoustic panel opposite to the reinforcement bar 22 may beconnected to the tank 2 or to another acoustic pane l 1 bymeans ofa dedicated supportstructure. P2024,0667 WO N / P240022WO01 September19,2025 -16 -During operation of the electric appliance 2, the a cousticpanels 1 dampen the noise in an electric power devi ce 20 ofthe electric appliance 2. For example, the electron ic powerdevice 20 may comprise or consist of a transformer, a phaseshifter,a reactororan inductor. In particular,almostthe complete outerwalls210 ofthe tank21 maybe covered byacousticpanels1.In particular, the noise reduction results from thedissipation of acoustic energy in the volume 13, inparticular in the filling material 14 as the fillin g materialis stimulated to vibrate by the inner plate 11 and / or theouter plate 12. These plates may vibrate with low o rder formsand therefore with high acoustic efficiency. In par ticular,the vibration of the inner plate 11 and / or the oute r plate 12may result from pressure waves in the air between t he outerwall210 ofthe tankand the acousticpanel1.As described above, the acoustic panel 1 can be spe cificallydesigned such thatthe noise reduction istuned to aparticular frequency band of the noise emitted by t heelectric appliance 2 during operation. The acoustic frequencybandsare specificto the electricappliance 2.Inparticular, these frequencies may also depend on th e netfrequencyofthe energydistribution network.For example, typical dominant noise frequencies are around100 Hz,120 Hzor300 Hzand 400 Hz.In addition to the frequency tuning elements 4, oth erparameters of the acoustic panel 1 may be appropria tely setto obtain an efficient noise reduction. For example , the P2024,0667 WO N / P240022WO01 September19,2025 -17 -filling material 14 has significant impact on the e fficiencyofthe noise reduction within a specificfrequency band.Forexample, the filling material 14 has a density in a rangefrom 0.5 g / cm³ to 5 g / cm³. Thus, the filling materi al has ascomparably high density. For example, the filling m aterialmay comprise a granular rubber material such as gra nular EPDM(ethylene propylene diene monomer).This material can be provided as recycling material , forexample.For example, a grain size of the filling material 1 4 is in arange from 0.1 mm to 5 mm.Alternatively, a filling material 14 having a lower densitymay be used. For example, the density of the fillin g materialis in a range from 5 kg / m³ to 500 kg / m³. For exampl e, amineralwooloran acousticfoam maybe used.The inner plate 11 and / or the outer plate 12 may ha ve athickness in a range from 2 mm to 6 mm. As the thic kness ofthe inner plate 11 and the outer plate 12 affects t hestiffness of the acoustic panel 1, the thickness of the innerplate 11 and / or the outer plate 12 may also be used to tunethe acousticfrequencyresponse.A thickness of the acoustic panel 1 may be in a ran ge from10 mm to 300 mm,forexample.In the embodiment of Figures 1A and 1B, the inner p late 11 ofthe acoustic panel 1 is spaced apart from the outer wall 210of the tank 21. However, the inner plate 11 may als o directlyadjoin the tank 21. For example, the distance betwe en the P2024,0667 WO N / P240022WO01 September19,2025 -18 -inner plate 11 of the acoustic panel 1 and the oute r plate210 of the tank 21 is in a range from 0 mm to 500 m m.For example, the inner plate 11 and / or the outer pl ate 12comprises a metal such as carbon steel, stainless s teel oraluminum ora plasticsmaterial.The embodiment illustrated in Figures 2A and 2B sub stantiallycorresponds to the embodiment of Figures 1A and 1B.In contrast, the frequency tuning elements 4 are fo rmed bystiffeners 42 arranged on the outer plate 12 of the acousticpanel 1. Alternatively or in addition, the inner pl ate 11 maybe provided with one ore more frequency tuning elem ents 4.The stiffeners 42 extend over at least 70 % of a la teralextent of the acoustic panel 1. For example, a late ral extente2 of the stiffener is at most 70 % of a width w1 o f theacousticpanel.It is noted that concentrated masses 41 and stiffen ers 42 mayalso be combined in an acoustic panel. For example, theacoustic panel 1 shown in Figures 1A and 1B may als o comprisestiffeners42 asillustrated in Figures2A and 2B.Figure 3 illustrates details of an embodiment of an acousticpanel 1 to be mounted to reinforcement bars 22 on a n outerwall210 ofthe electricappliance 2.The acoustic panel1comprises an inner plate 11 and an outer plate 12 e xtendingin parallel to one another. A sidewall 19 is arrang ed betweenthe inner plate 11 and the outer plate 12. As illus trated inFigure 3 a volume 13 between the inner plate 11 and the outerplate 12 may be subdivided into a plurality of cham bers 16. P2024,0667 WO N / P240022WO01 September19,2025 -19 -For example, the chambers 16 may help to maintain ahomogenousdistribution ofthe filling material14 within thevolume 13 over time. However, these chambers 16 are notnecessarilyrequired.The acoustic panel 1 comprises a mounting region 15 . Themounting region 15 laterally extends beyond the inn er plate11 and is configured to overlap with the reinforcem ent bar 22when mounted to the outerwall210 ofthe tank21. In theembodiment of Figure 3 the mounting region 15 is fo rmed by apart of the outer plate 12. Alternatively, the moun tingregion 15 mayalso be formed bya separate element attached to the outerplate 12 asillustrated in Figure 5A, for instance.The mounting region 15 and means for mechanically m ountingthe acoustic panel 1 to the reinforcement bars 22 m ay beadapted to the cross-section of the reinforcement b ars 22. InFigure 3, the reinforcement bars 22 have a T-shaped cross-section. However, other geometries may also be used for thereinforcement bars, for example a U-shaped or subst antiallyrectangular cross-section of the reinforcement bars 22. Othercross-sections such as C-shaped, L-shaped, or I-sha ped mayalso be used.Figures 4A and 4B illustrate an embodiment of an ac ousticpanel 1 mounted to a T-shaped reinforcement bar 22. Asdescribed in connection with Figure 3, the mounting region 15overlaps with the reinforcement bar 22. The mechani calconnection between the acoustic panel 1 and the rei nforcementbar 22 is obtained via a clamp 31 that directly adj oins thereinforcement bar 22 and is secured to the acoustic panel 1via a washer33 and a nut32. P2024,0667 WO N / P240022WO01 September19,2025 -20 -A sealing and / or damping material 222 is arranged b etween themounting region 15 of the acoustic panel and the su rface 220of the reinforcement bar 22, for example the dampin g materialcomprises a rubber. The frequency tuning elements 4 may beconfigured asdescribed in connection with Figures 1A and 1Bor Figures 2A and 2B, for example and are not expli citlydepicted foreasierrepresentation.In the embodiments of Figures 5A and 5B, the reinfo rcementbars 22 have a U-shaped cross-section. In the embod iment ofFigure 4A, the mounting region 15 is formed by an e xtension151 attached to the outerplate 12 ofthe acoustic panel.Theextension 151 has a hole or a cutout to receive a s crew 34extending into a blind bushing 225 of the reinforce ment bar22. The frequency tuning elements 4 may be configur ed asdescribed in connection with Figures 1A and 1B or F igures 2Aand 2B, for example and are not explicitly depicted foreasierrepresentation.The embodiment of Figure 5B substantially correspon ds to theembodiment of Figure 5A. However, the mounting regi on 15 isformed by a portion of the outer plate 12 that over laps withthe reinforcementbar22.Figures 6A and 6B illustrate two side views of an e lectricappliance 2 with a tank 21 and a plurality of acous tic panels1 that may be configured as described in the previo usfigures. Figure 5B further schematically illustrate s theelectric power device 20 immersed in a liquid withi n tank 21.Figures 6A and 6B illustrate that almost the entire surfaceof the outer wall 210 of the tank 21 may be covered with P2024,0667 WO N / P240022WO01 September19,2025 -21 -acoustic panels 1 so that an efficient noise reduct ion can beobtained. Compared to conventional solutions, the a cousticpanels1 do notsignificantlyincrease the size of theelectric appliance 2. Further, access to the tank 2 1 isfacilitated. The frequency tuning elements 4 may beconfigured asdescribed in connection with Figures 1A and 1Bor Figures 2A and 2B, for example and are not expli citlydepicted foreasierrepresentation.Figure 7 illustrates an embodiment of a method of a ssemblingan electric appliance. For better understanding, st ructuralfeaturesdescribed in connection with the previous figuresare used even though these elements are not explici tly shownin Figure 7.In a step S1, an electric power device 20 is provid ed. In astep S2, a tank is formed that extends around the e lectricpowerdevice.The tank21 comprisesa pluralityofreinforcement bars 22 arranged on an outer wall 210 of thetank 21. In a step S3, an acoustic panel 1 is mount ed to atleast one of the plurality of reinforcement bars 22 whereinthe innerplate ofthe acousticpanel1 islocated closertothe outer wall of the tank 21 than a surface 220 of thereinforcement bar 22 that faces away from the tank.The method can be performed in the indicated order.However,thisisnotnecessarilyrequired.Rather, atleast partofstep S3 maybe performed priorto step S2. Forexample, at least one acoustic panel 1 may be preas sembled toa partofthe tank.Thus,partsofthe tankmaybe provided with an acousticpanelbefore the tank21 hasbeen completed. P2024,0667 WO N / P240022WO01 September19,2025 -22 - Thismayhelp to facilitate the assembling process ofthe electricappliance.In particular, the method can be used to assemble a n electricappliance 2 configured as described in connection w ith thepreviousfigures.The embodiments shown in the Figures 1A to 7 as sta tedrepresent exemplary embodiments of the acoustic pan el, of theelectric appliance of the method; therefore, they d o notconstitute a complete list of all embodiments accor ding tothe acoustic panel, the electric appliance, and the method.Actualacousticpanelsand electricappliancesand methodsmay vary from the embodiments shown in terms of spa tialarrangements, components, and materials, for exampl e.

[0002] P2024,0667 WO N / P240022WO01 September19,2025 -23 - Reference Signs 1 acousticpanel 11 innerplate 12 outerplate 13 volume 14 filling material 15 mounting region 151 extension 16 chamber 19 side wall 2 electricappliance 20 electricpowerdevice 21 tank 210 outerwall 22 reinforcementbar 220 surface ofreinforcementbar 221 gap 222 sealing and / ordamping material 225 blind bushing 31 clamp 32 nut 33 washer 34 screw 4 frequencytuning element 41 concentrated mass 42 stiffener S1 step S2 step S3 step w1 width e1 lateralextentofconcentrated mass P2024,0667 WO N / P240022WO01 September19,2025 -24 -e2 lateral extent of stiffener

Claims

P2024,0667 WO N / P240022WO01 September19,2025 -25 - Claims1. An electric appliance (2) comprising an acoustic panel (1)and a tank(21),wherein- the acoustic panel (1) comprises an inner plate ( 11) facingthe tank (21) and an outer plate (12) facing away f rom thetank(21),- a volume (13) between the inner plate (11) and th e outerplate (12)isfilled with a filling material(14),- the acoustic panel (1) is mounted to at least onereinforcement bar (22) on an outer wall (210) of th e tank(21) wherein the inner plate (11) of the acoustic p anel (1)is located closer to the outer wall (210) of the ta nk (21)than a surface (220)ofthe reinforcementbar(22) thatfaces awayfrom the tank(21),and- the acoustic panel (1) comprises a concentrated m ass (41)as a frequency tuning element (4) that is located w ithin thevolume (13) and is configured to tune a specific ac ousticdampening frequency band of the acoustic panel (1), and- a density of the concentrated mass (41) is at lea st by 50 %largerthan a densityofthe filling material(14) andwherein a lateral extent (e1) of the concentrated m ass is atmost 50 % of a lateral extent of the acoustic panel when seenalong the same direction. 2.The electricappliance according to claim 1,wherein a mass of the concentrated mass is in a ran ge from0.2 kg to 10 kg.

3. The electric appliance according to claim 1 or 2 ,wherein the frequencytuning element(4)comprises astiffener (42) configured to stiffen the inner plat e (11) orthe outerplate (12).P2024,0667 WO N / P240022WO01 September19,2025 -26 - 4.The electricappliance according to claim 3,wherein the stiffener (42) extends over at least 70 % of theacousticpanel(1)along a lateraldirection.

5. The electric appliance according to claim 3 or 4 ,wherein the stiffener(42)isformed from the same material asthe innerplate (11)orthe outerplate (12).

6. The electric appliance according to claim 3 or 4 ,wherein a material of the stiffener (42) is differe nt from amaterial of the inner plate (11) or the outer plate (12).

7. The electric appliance according to any one of t hepreceding claims,wherein the acoustic panel (1) comprises a mounting region(15) for mounting the acoustic panel (1), wherein t hemounting region (15)laterallyprojectsbeyond the inner plate (11).

8. The electric appliance according to any one of t hepreceding claims,wherein the acoustic panel (1) comprises a mounting region(15) that overlaps with one of the reinforcement ba rs (22),wherein a sealing and / ordamping material(222)is arrangedbetween the mounting region (15) and the reinforcem ent bar(22).

9. The electric appliance according to any one of t hepreceding claims, wherein a distance between the innerplate (11)of the acousticpanel(1)and the outerwall(210)ofthe tank(21) isin a range from 0 mm to 500 mm.P2024,0667 WO N / P240022WO01 September19,2025 -27 -10. A method of assembling an electric appliance (2 )according to any one of claims 1 to 9, comprising t he stepsof:a)providing an electricpowerdevice (20);b) forming a tank (21) that extends around the elec tric powerdevice (20), wherein the tank (21) comprises a plur ality ofreinforcement bars (22) arranged on an outer wall ( 210) ofthe tank(21);andc) mounting an acoustic panel (1) to at least one o f theplurality of reinforcement bars (22) wherein the in ner plate(21) of the acoustic panel (1) is located closer to the outerwallofthe tank(21)than a surface (220)ofthereinforcement bar (22) that faces away from the tan k (21).11.The method according to claim 10, wherein step c)isperformed priorto step b).

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