WO2008092223A2

WO2008092223A2 - Resonator arrangement for the cabinet of a refrigeration appliance

Info

Publication number: WO2008092223A2
Application number: PCT/BR2008/000030
Authority: WO
Inventors: Edmar Baars; Otávio SANTINI JÚNIOR
Original assignee: Whirlpool S.A.
Priority date: 2007-01-30
Filing date: 2008-01-29
Publication date: 2008-08-07
Also published as: CN101641559A; IN2009KN02416A; BRPI0700554A; JP2010516992A; WO2008092223A3; KR20090115153A; EP2115367A2; RU2415354C1; US20100095698A1

Abstract

The invention refers to a resonator arrangement for the cabinet of a refrigeration appliance, said cabinet (3) defining a housing (1) and carrying, in the latter, a compressor (2) presenting a hermetic casing (2a) and a defrost water evaporating tray (10) comprising: a bottom wall (11), to be seated onto an upper portion of the casing (2a) of the compressor (2); and a peripheral wall (12) superiorly projecting from the bottom wall (11), at least one of the peripheral wall (12) and bottom wall (11) of the evaporating tray (10) carrying a noise absorbing means turned to a noise generation region in said housing (1) and being dimensioned to define a certain reactive impedance and a certain dissipative impedance in the medium of the housing (1) for a determined frequency band.

Description

RESONATOR ARRANGEMENT FOR THE CABINET OF A REFRIGERATION APPLIANCE Field of the Invention

The present invention refers to a resonator arrangement to be provided in the cabinet of a refrigeration appliance, particularly in the region thereof that houses a compressor of a refrigeration system of said refrigeration appliance, in which is common the occurrence of noise resulting from the operation of the compressor and/or fan provided in the region of said housing. In a more specific way, the present invention refers to a resonator arrangement to be provided in a defrost water evaporating tray of refrigeration systems of refrigerator appliances, said evaporating tray being of the type affixed on the casing of the hermetic compressor of said refrigeration systems. Background of the Invention

The noise radiated by the refrigerator can be defined in two regions in the spectrum: in frequencies below about 2kHz and in those frequencies above this value.

In a first spectral region, defined by lower frequencies, there is a strong interaction between the refrigeration appliance and the compressor, through the excitation of the first acoustic resonances of a housing defined in a back lower region of the refrigeration appliance, in which is mounted the compressor of the refrigeration system of this refrigeration appliance. These frequencies basically rely on the dimensions of the housing of the compressor and the spectral composition of the noise radiated by the latter. Other common source of noise in a refrigeration appliance is the fan, which is generally positioned in said refrigeration appliance in the housing in which the compressor is mounted. Besides generating high frequency noises produced by turbulences, the fan presents strong radiation in the blade passage frequency, which is the product of the number of blades by the rotation frequency. In a second spectral region, in which the frequencies are generally above 2kHz, the compressor radiates noise directly, without much interference of the structure or form of the housing in which said compressor is mounted to the refrigeration appliance.

The literature is rich in examples and applications of noise control techniques. (Hansen, H. "Engineering Noise Control", 2003, Spon Press; Lyon, R. H., "Machinery Noise and Diagnostics", 1987, Butterworth Publishers; Munjal, M. L. "Acoustics of Ducts and Mufflers", 1987, New York Wiley-Interscience) . In a known conventional prior art, a housing 1, in which is mounted a compressor 2, is coated with an acoustic material MA (figure 2) , which housing 1 can also be closed by a plate P, defining an end lid, internally provided with acoustic material MA for coating the housing, which for example and as illustrated in figure 3, may not receive the material in its inner walls. In this solution, the compressor remains closed in the interior of the housing 1, by closing the latter.

When the above-described control techniques cannot be used, the control must be made in the compressor, by increasing the thickness of the 'casing or by adding dampening elements thereto.

These techniques present some drawbacks, such as: high cost of the acoustic material for' coating or closing,- the need to perform alterations in the compressor, raising its cost; increase of the compressor temperature; reduction in the fan efficiency; reduction in the compressor efficiency; and requirement of additional steps in the process for obtaining the refrigeration appliance, as a function of the need for a process . for mounting and placing a coating and closing element of the housing, enclosing the compressor in the refrigeration appliance. Objects of the Invention

It is a first object of the present invention to provide a resonator arrangement for the cabinet of a refrigeration appliance, which allows the noise radiated by the compressor to be efficiently attenuated in a broad band of frequencies, both in the low and high frequencies .

It is a second object of the present invention to provide a resonator arrangement, as cited above, which permits an efficient attenuation, in a broad band of frequencies, of the noise generated by a fan mounted in the refrigeration appliance, in the region thereof that houses the compressor.

It is a third object of the present invention to provide a resonator arrangement, as cited above, which permits an efficient attenuation, in a broad band of frequencies, of the noise radiated by the refrigeration system.

It is a fourth object of the present invention to provide a resonator arrangement, as cited above, which permits an efficient attenuation of the resonances in the interior of the housing in which the compressor is mounted in the refrigeration appliance.

It is a fifth object of the present invention to provide a resonator arrangement of the above-cited type, which does not require an acoustic coating of the housing in which is mounted the compressor in the refrigeration appliance, nor modifying the dimensioning of said housing. It is a sixth object of the present invention to provide a resonator arrangement of the above-cited type, which does not require modifying the dimensioning and/or thickness of the compressor casing. Summary of the Invention These and other objects of the present invention are attained through the provision of a resonator arrangement for the cabinet of a refrigeration appliance, said cabinet defining a housing and carrying, in the latter, a compressor presenting a hermetic casing and a defrost water evaporating tray, comprising: a bottom wall, to be seated onto an upper portion of the casing of the compressor; and a peripheral upper wall projecting from the bottom wall, at least one of the peripheral wall and bottom wall of the evaporating tray carrying a noise absorbing means, generally at least one resonator conduct, which is turned to a noise generation region in said housing and being dimensioned to define a certain reactive impedance and a certain dissipative impedance in the medium of the housing, for a determined frequency band. Brief Description of the Drawings The invention will be described below, with reference to the appended drawings, given by way of example of possible embodiments of the invention and in which: Figure 1 schematically represents a longitudinal sectional view of a refrigeration appliance in which is inferiorly rearly defined a housing in which is mounted a refrigeration compressor superiorly externally carrying an evaporating tray;

Figure 2 schematically represents a longitudinal sectional view illustrated in figure 1, but in which the housing in which is mounted the refrigeration compressor is coated with a noise absorbing material, according to the prior art;

Figure 3 schematically represents a partial sectional side view of the refrigeration appliance illustrated in figure 1 and having the refrigeration compressor housing closed by a noise absorbing wall, constructed according to the prior art;

Figure 4 schematically represents an enlarged view of the refrigeration compressor carrying the evaporating tray, as illustrated in figure 1, but said evaporating tray being constructed according to a first constructive option of the present invention; Figure 4a schematically represents, as illustrated in figure 4, a variant of the first constructive option for the evaporating tray, according to the present invention; Figure 5 schematically represents a top plan view of the evaporating tray illustrated in figure 4; Figure 6 schematically represents a longitudinal sectional view of the evaporating tray illustrated in figure 5, taken according to line VI-VI indicated in said figure 5;

Figure 7 schematically represents a view, as illustrated in figure 5, for a second constructive option of the present invention; Figure 8 schematically represents a view, as illustrated in figure 6, taken second line VIII-VIII indicated in figure 7;

Figure 9 schematically represents a view, as illustrated in figure 5, for a third and a fourth constructive option of the present invention; Figure 9a schematically represents a view, as illustrated in figure 9, for a constructive variant of the third and the fourth constructive option illustrated in figure 9; Figure 10 schematically represents a view as illustrated in figure 8, taken second line X-X, indicated in figure 9;

Figure 11 schematically represents a view, as illustrated in figure 9, for a fourth constructive option of the present invention; Figure 12 schematically represents a view, as illustrated in figure 10, taken second line XII-XII indicated in figure 11;

Figure 13 schematically represents a view, as illustrated in figure 9, for a fifth constructive option of the present invention;

Figure 14 schematically represents a view, as illustrated in figure 13, taken second line XIV-XIV indicated in figure 13.

Figure 15a schematically represents a view, as illustrated in figure 8, for a sixth constructive option of the present invention; Figure 15b schematically represents a view, as illustrated in figure 15a, for a variant of the sixth constructive option of the present invention; Figure 15c schematically represents a view, as illustrated in figure 15a, for another variant of the sixth constructive option of the present invention;

Figure 15d schematically represents a view, as illustrated in figure 15a, for a seventh constructive option of the present invention; Figure 16a schematically represents a view, as illustrated in figure 10, for an eighth constructive option of the present invention, taken second line XVI- XVI, indicated in figure 9;

Figure 16b schematically represents a view, as illustrated in figure 16a, for a variant of the eighth constructive option of the present invention;

Figure 16c schematically represents a view, as illustrated in figure 16a, for another variant of the eighth constructive option of the present invention; Figure 17a schematically represents a view, as illustrated in figure 10, for a ninth constructive option of the present invention, taken according to line XVII-XVII, indicated in figure 9;

Figure 17b schematically represents a view, as illustrated in figure 17a, for a first variant of the ninth constructive 'option of the present invention;

Figure 17c schematically represents a view, as illustrated in figure 17a, for a according to variant of the ninth constructive option of the present invention; Figure 17d schematically represents a view, as illustrated in figure 17a, for a third variant of the ninth constructive option of the present invention; and Figure 17e schematically represents a view as illustrated in figure 17a, for a fourth variant of the ninth constructive option of the present invention. Description of the Illustrated Embodiments The present invention provides a solution for attenuating the noises produced in the region of the above-defined housing 1 which is provided in a back lower region of a cabinet 3 of a refrigeration appliance (for example, in the form of refrigerator or freezer) .

The housing 1 is defined by a recess in a rear wall 3a of the cabinet 3 of the refrigeration appliance. As illustrated, the compressor 2 superiorly carries an evaporating tray 4, dimensioned to receive and store the water coming from the defrost process of the refrigeration system of a refrigeration appliance, said evaporating tray 4 being of the type to be attached to a hermetic casing 2a of the compressor 2 of said refrigeration system. In this constructive solution, the seating of the evaporating tray 4 onto the casing 2a of the compressor 2 allows the first to be subject to the heat produced by the compressor 2 in operation, promoting the evaporation of the collected water. The evaporating tray 4 is retained to the compressor 2 by appropriate means, as glue, adhesive, etc., which is not a characteristic of the present solution.

As illustrated in the drawings, in a possible construction, the evaporating tray 4 is produced in a high temperature-resistant plastic material, as highly- resistant polypropylene, and generally injection molded to its final form comprising ^■ a bottom wall 4a incorporating a peripheral wall. 4b with a height sufficient to define the collecting volume of the defrost water required by the refrigeration system to which it will be applied. In a constructive option, the evaporating tray 4 is formed in a single piece. The bottom wall 4a of the evaporating tray 4 can be provided with a lower recess (not illustrated) , generically defined as a lower surface, dimensioned to

1 seat onto a certain extension of the end face of the casing 2a of the compressor 2. It should be understood that the lower recess can be shaped and dimensioned to accompany the contour of the upper portion of the casing 2a of the compressor 2, to allow the fitting and seating of the evaporating tray 4 onto said upper portion of the casing 2a of the compressor 2, increasing the positioning stability onto the latter and incrementing the thermal exchange with the compressor 2. According to the present invention, the noise attenuation in the housing 1 is obtained by the provision of an evaporating tray 10 carrying a noise absorbing means, which is disposed facing a noise generation region in said housing 1, said noise absorbing means being dimensioned to define a certain reactive impedance and a certain dissipative impedance in the medium of the housing 1, for at least one determined specific frequency band or also for all the frequencies in which there is generation of noise. The noise absorbing means carried by the evaporating tray 10 can take different constructive forms within the concept presented herein, some of which will be discussed below.

As described below, the present invention allows attenuating the noise radiated by the compressor 2 or other sources, as fans, for example, mounted in the housing 1 of the refrigeration appliance. Besides, the noise absorbing means of the present invention can also be used to totally or partially cancel the effect of the resonances provoked in the housing 1 of the cabinet 3 of the refrigeration appliance.

The evaporating tray 10 of the present invention presents a bottom wall 11 and a peripheral wall 12, which are arranged in a construction with a form similar to that of the prior art evaporating tray 4. In a way of carrying out the present invention, the noise absorbing means comprises at least one resonator conduct 20, provided in the evaporating tray 10, disposed along an extension of at least one of the bottom wall 11 and peripheral wall 12 of the evaporating tray 10, said resonator conduct 20 presenting an arrangement in said evaporating tray 10 defined so that a first end 21 of the resonator conduct 20 is disposed turned to the noise generation region in the housing 1. The resonator conduct 20 further presents a second end 22, opposite to and spaced from the first end 21. Although the objects of the present invention can be attained with one resonator conduct 20, the constructive forms described and illustrated in figures 4-14 present the evaporating tray 10 carrying, in at least one of its bottom wall 11 and peripheral wall 12, a noise absorbing means comprising a plurality of resonator conducts 20, at least part of which presenting the arrangement defined above, in which a first end 21 of each said resonator conduct 20 is turned to the noise generation region in the housing 1. Each resonator conduct 20 is dimensioned to present a determined length and a determined diameter, which are calculated to define a certain reactive impedance and a certain dissipative impedance in the medium of the housing 1, for at least one determined frequency band. The length of the resonator conducts 20 is calculated taking into account frequencies or frequency band desired to be attenuated, the difference between the lengths of the resonator conducts 20 depending on both the band width and the attenuation required for each case, i.e., for the characteristics of each housing 1 to be considered. According to the present invention, at least part of the resonator conducts 20, in any of the constructions described herein, can present a constant or variable cross-section along their length, the contour and the behavior of said cross-section being defined as a function of the attenuation effect to be obtained, and of the facility for making them, etc. Some of the possible cross-sections within the desired attenuation concept are, as to the variation: cylindrical, conical, exponential or stepped and, as to the contour: regular, such as rectangular, circular, polygonal or even irregular, as is the case of fibrous material pores. In order to have the desired effect, the resonator conducts 20 must be tuned in the frequencies or frequency bands which present the levels desired to be controlled, which tuning is obtained through the length and the type of termination of the second end 22, whether closed or open, of each resonator conduct 20. In a preferred form of the present invention, the second end 22 of each resonator conduct 20 is closed. However, it should be understood that, according to the present invention, the second end 22 can be open, said condition being defined as a function of the desired attenuation characteristics and of the arrangement of the respective resonator conduct 20 in the evaporating tray 10 and/or also in other body carrying said resonator conduct 20, such as a tubular sleeve 30 or peripheral ring 40, to be described below. The quantity of resonator conducts 20 is calculated considering the tuning thereof in different frequencies, in order to propitiate attenuation of the noise radiated by the compressor 2 in several different frequencies. Such frequencies can be very separated or close, creating an attenuation band.

The evaporating tray 10 carries the noise absorbing means in description, in the form of a resonator conduct 20, for example, by incorporating, through one of the inner and outer surfaces of at least one of its bottom wall 11 and peripheral wall 12, as illustrated in figures 4, 4a, 7 and 8, or also each resonator conduct 20 being formed either in the thickness of the bottom wall 11 or peripheral wall 12 (or in both) of said evaporating tray 10, as illustrated in figures 5 and 6.

The incorporation of each resonator conduct 20 can be total (figures 4, 4a, 7 and 8), as in the case in which said resonator conduct 20 is formed in the thickness of the respective wall of the evaporating tray 10, or partial (figures 11-14) , in the cases in which the adjacent surface portion of the respective bottom wall 11 and/or peripheral wall 12 of the evaporating tray 10, which provides the resonator conduct 20 defines, for example, in a single piece, at least part of the length of said resonator conduct 20. In these cases, the part which complements the cross-section of the resonator conduct 20 can be defined by one of the constructive forms described below, by using a tubular sleeve 30, a peripheral ring 40, or also by incorporating, to each resonator conduct 20, by appropriate means, a respective complementary element which, mounted to the resonator conduct 20 formed in the evaporating tray 10, complements the peripheral contour of said resonator conduct 20, resulting in a closed cross-section thereof, at least along the length of said resonator conduct 20, responsible for attenuating the noise in the frequency band to which said resonator conduct 20 was designed. Taking into account the distribution of the noise to be attenuated in the housing 1 for constructing the noise absorbing means in description, utilizing resonator conducts 20, the present invention permits the provision of different arrangements of resonator conducts 20 in the evaporating tray 10, the quantity of resonator conducts 20 of the same arrangement and with the same dimensional and arrangement characteristics in the evaporating tray 10 being calculated as a function of the region in which the highest noise is detected in the housing 1 and of the frequency band to be attenuated in this region. In a way of carrying out the present invention, the resonator conducts 20 present at least one of the diameter and length parameters with the same value. However, it should be understood that the dimensions of the resonator conducts 20 can be equal or different, depending on the intended result of attenuation. Thus, if it is desired to broaden the frequency band to be attenuated, such dimensions are different, even though only slightly different from one another. If the attenuation must be greater in a determined narrower frequency band, the resonator conducts 20 must have the same dimensions.

The resonator conducts 20 are carried by the evaporating tray 10, in order to prevent or attenuate the propagation of the sound waves, reflecting or dissipating these waves. Such resonator conducts 20 alter locally the impedance. When applied in the regions of maximum modal pressure, the resonator conducts 20 operate withdrawing energy (dissipation) from the region of the housing 1, reducing the effects of the resonances. In a general way, the resonator conducts 20 increase the acoustic attenuation in the frequencies in which they are tuned.

It should be understood that the evaporating tray 10 can carry the resonator conducts 20 directly defined in at least one of the bottom wall 11 and peripheral wall 12, or also, at least partially, through a tubular sleeve 30, or peripheral ring 40, as described ahead. For any of the possible forms by which the evaporating tray 10 carries the resonator conducts 20, it should be noted that, as a function of the dimensioning of the housing 1 of the cabinet 3 of the refrigeration appliance, the resonator conducts 20 must have their ends superiorly disposed on the evaporating tray 10, not relevantly projecting from the upper edge of said evaporating tray 10, preferably at maximum coinciding with said upper edge of the evaporating tray 10. The end of each resonator conduct 20 inferiorly disposed on the evaporating tray 10 can be positioned beyond a lower contour of the peripheral wall 12 of said evaporating tray 10, as long as this projecting positioning neither interferes with the arrangement of the evaporating tray 10 onto the refrigeration compressor 1, nor with the dimensioning and operation of the latter.

In the construction in which the evaporating tray 10 carries the tubular sleeve 30, the latter is provided adjacent to one of the bottom wall 11 and peripheral wall 12 of the evaporating tray 10, internally or externally to this and disposed around the whole peripheral contour of the adjacent bottom wall 11 or peripheral wall 12, the cross-section of at least one resonator conduct defined by the parts of evaporating tray 10 and tubular sleeve 30 being partially defined in each of said parts.

The tubular sleeve 30 can surround at least part of the longitudinal extension of the wall of the evaporating tray 10 that carries it, each resonator conduct 20 having part of its cross-section defined in one of the confronting and adjacent surfaces of said wall of the evaporating tray 10 and of the tubular sleeve 30. In this way of carrying out the present invention, at least part of the resonator conducts 20 present at least part of their length defined from the complementation of two parts: one defined in the wall of the evaporating tray 10 and the other by the tubular sleeve 30 carried by the evaporating tray 10. In the illustrated constructions, the tubular sleeve 30 presents a determined wall thickness previously defined as a function of structural rigidity, cross-section of the conducts which it partially defines, said tubular sleeve 30 presenting an inner surface confronting with an adjacent surface of the evaporating tray 10, the contour and the cross-section of the resonator conducts 20 being partially defined in each of the adjacent confronting surfaces of tubular sleeve 30 and adjacent wall of the evaporating tray 10.

According to the present invention, at least one of the resonator conducts 20 has at least part of its length extending along an extension of the respective bottom wall 11 and/or peripheral wall 12 of the evaporating tray 10 and/or of the tubular sleeve 30, in a straight or curvilinear form. In a way of carrying out the present invention, the resonator conducts 20 are straight in at least part of their extension. In a constructive variant of the present invention, at least two resonator conducts 20 are parallel to one another, or also parallel to one another in sets of resonator conducts 20, said resonator conducts 20 being vertically or horizontally arranged in the respective part of evaporating tray 10 and/or tubular sleeve 30.- The arrangement of at least part of the resonator conducts 20 can also be inclined in relation to the longitudinal length of the wall of the evaporating tray 10 and/or of the tubular sleeve 30 in which at least part of said resonator conduct 20 is provided, said arrangement being, for example, diagonal to said wall in which the resonator conducts 20^' are provided. These constructive arrangements with distinct inclination of the resonator conducts 20 in relation to an adjacent wall of the evaporating tray 10 can also occur in the constructions in which said resonator conducts 20 are partially or totally carried by the tubular sleeve 30 or by the peripheral ring 40. The form of the resonator conducts 20, for example, parallel, horizontal, vertical, inclined, straight, curvilinear, or a combination thereof, depends on the desired attenuation effect that said resonator conducts 20 must carry out in the housing 1 and/or on the direction in relation to the noise generation region of at least one first end of said resonator conducts 20. In the illustrated embodiment of figure 4a, a resonator conduct 20 is horizontally disposed on the peripheral wall 12 of the evaporating tray 10, whilst the others are vertically disposed. It should be understood that the arrangement of the resonator conducts 20, in the part that carries them, is defined as a function of the necessary directioning of said resonator conducts 20 to the region of the housing 1 with noise to be attenuated. Thus, there are also possible constructions with bundles of resonator conducts 20 disposed on the evaporating tray 10 and/or tubular sleeve 30 in distinct directions, which are defined so that the first end 21 of the resonator conducts 20 of each bundle of the latter is directed to a determined region of the housing 1 to be attenuated, said bundles of resonator conducts 20 being dimensioned as a function of the frequency band to be attenuated in each region to which a bundle of first ends 21 is directed. The arrangement of resonator conducts 20 of the present invention allows each resonator conduct to be tuned in a different frequency, but very close to that of another resonator conduct 20, for example, an adjacent resonator conduct 20, in order to result in a broad frequency band to be attenuated by the arrangement of said resonator conducts 20. In the constructive form in which the resonator conducts 20 are at least partially carried by an adjacent surface portion of the respective wall of the evaporating tray 10, these resonator conducts 20 can be in the form of closed pipes affixed to said wall surface portion of the evaporating tray 10, or said pipes can define part of the cross-section of the resonator conduct 20, whilst the other part is defined by an adjacent confronting surface portion of the tubular sleeve 30 disposed on the evaporating tray 10, in order to complete the peripheral contour of each resonator conduct 20 defined by the parts of evaporating tray 10 and tubular sleeve 30. In this constructive option, each resonator conduct 20 is defined by a recess, to be described ahead, produced in at least one of the confronting surfaces of the evaporating tray 10 and of the tubular sleeve 30. In the constructive option illustrated in figures 4-6, the resonator conducts 20 are defined in a single piece with the evaporating tray 10, for example, during the formation of the latter, said resonator conducts 20 being previously defined in the mold that forms the evaporating tray 10. However, it should be noted that the resonator conducts 20 can be provided after the formation of the evaporating tray 10, for example, by mounting, to at least part of the peripheral wall 12 thereof, a plurality of pipes, each defining a resonator conduct 20. In this constructive variant, the peripheral wall 12 can be hollow, in which are housed and/or retained the resonator conducts 20, or carry a peripheral flange surrounding part or the whole of the peripheral contour of the peripheral wall 12 of said evaporating tray 10 and supporting an adjacent peripheral edge portion of each resonator conduct 20.

In the constructive variant illustrated in figures 4, 4a, 7 and 8, the resonator conducts 20 are provided in a single piece with the evaporating tray 10, for example, during the formation of the latter, as described above or said resonator conducts 20 are affixed, by appropriate means, to the outer face of the peripheral wall 12. While the constructive forms of evaporating tray 10 incorporating the resonator conducts 20 present the advantage of facilitating the formation of said resonator conducts 20 with a reduced cost, the constructive forms carrying, by mounting and/or affixing, said resonator conducts 20 in the evaporating tray 10, present the advantage of higher flexibility in the desired formation of particularized resonator arrangement!s for a determined region of the housing 1 likely to have a higher amount of noise to be attenuated, and for one or more frequency bands to be locally attenuated. Other advantage of this construction is that such arrangement can be also provided in evaporation trays already commercialized. In another constructive option of the present invention, described below, the evaporating tray 10 carries the resonator conducts 20 by mounting, around at least part of the contour of its peripheral wall 12, a tubular sleeve 30, which defines wholly (figures 9, 9a and 10) or partially (figures 11-14) the resonator conducts 20.

In the constructive form illustrated in figure 9a, the tubular sleeve 30 is mounted around the whole contour of the adjacent peripheral wall 12 of the evaporating tray 10, so as to have an inner face confronting with the outer : face of said peripheral wall 12 of the evaporating tray 10, close to which said tubular sleeve 30 is provided. In this construction, the tubular sleeve 30 is conformed to present a profile coincident with that of the peripheral wall 12 of the evaporating tray 10, in order to be tightly fitted around it, or with a radial gap previously defined in the project. In the construction illustrated in figure 9, the evaporating tray 10 carries, around part of the contour of its peripheral wall 12, the tubular sleeve 30, which is affixed to said evaporating tray 10 by appropriate means, such: as glue, clamps, fittings of male-female type provided in said parts of evaporating tray 10 and tubular sleeve 30, or other appropriate means. In the illustrated construction, the fixation of the tubular sleeve 30 to the evaporating tray 10 is made by seating an inner flange (not illustrated) against an adjacent edge of the peripheral wall 12 of the evaporating tray 10, said seating being maintained through appropriate fixation means, such as mechanical interference, clamps, screws, etc. The tubular sleeve 30 presents an upper flange 30a, peripherally defining an edge of the tubular sleeve 30 external to the resonator conducts 20.

In the constructive option illustrated in figures 11- 14, the peripheral contour of each resonator conduct 20 is partially defined by the peripheral wall 12 of the evaporating tray 10 and partially defined by the adjacent confronting face of the tubular sleeve 30, so that the complementation of said contours defines the cross-section of each resonator conduct 20. In the constructive variant illustrated in figures 11 and 12, the tubular sleeve 30 is conformed to define a portion of the contour of each resonator conduct 20, for example, in the form of a recess 33 defining an arched portion of the respective resonator conduct 20, the adjacent end face of the peripheral wall 12 of the evaporating tray 10 defining a rectilinear contour for each resonator conduct 20. In this constructive variant, the evaporating tray 10 presents the same configuration of the conventional evaporation trays 4, the volume of each resonator conduct 20 being defined by the form of the tubular sleeve 30. Although a construction is illustrated in which the contour of each resonator conduct 20 is arched, it should be understood that other forms of contour are possible within the concept presented herein. In this construction, the tubular sleeve 30 is provided with, for example, arched recesses 33, each defining part of a respective resonator conduct 20. Each recess 33 can be provided along the length of the respective peripheral wall 12 of the evaporating tray 10, or inclined in relation to the plane of the rear wall of the cabinet 3 of the refrigeration appliance in which the housing 1 is defined. In the constructive variant illustrated in figures 13 and 14, the inner face of the tubular sleeve 30 and the outer face of the evaporating tray 10 are conformed to define part of the contour of each resonator conduct 20. In this construction, each part of evaporating tray 10 and tubular sleeve 30 is provided with a respective recess 13, 33, as presented above, and which defines a respective part of the contour of a resonator conduct 20. In this constructive option, each recess 13, 33 defines part of an arched contour of a respective resonator conduct 20.

It should be understood that the resonator conducts 20 can be provided in only part of the extension of the peripheral wall 12 of the evaporating tray 10 and/or of the tubular sleeve 30, and the positioning of said resonator conducts 20 can also be defined in a certain direction for specific attenuation of a noise or a determined desired frequency band. This construction allows specific and directed arrangements of resonator conducts 2,0 in the region of the housing 1, according to the detected need.

According to the present invention, at least one of the parts of bottom wall 11 and peripheral wall 12 of the evaporating tray 10, of tubular sleeve 30 and at least one resonator conduct 20 can also be defined in a porous or fibrous material (figure 15d) , as long as this defines pores. In this solution, the part defined in porous material can, for example, be obtained by injection directly in porous material. In the case of the evaporating tray 10 in porous material, it is injected, in a single piece, for example in polymer or also in a fibrous material. In the constructions in which the evaporating tray 10 defines a single piece with the resonator conducts 20, the latter also can be obtained during the injection of porous material, which also defines the noise absorbing means of the present invention. However, it should be understood that the desired noise attenuation effect can be obtained with at least one of said parts coated with a porous material (figures 15a- 15c) . The coating can be obtained, for example, with pieces in the form of plates of porous or fibrous material added to the respective part by an appropriate fixation means, which coating material can be disposed in said part in any position and geometry defined as a function of the region presenting noise to be attenuated.

It should be further considered that some of said above-defined parts can be coated in porous material, while others can be directly produced in porous material having the desired noise absorbing characteristics which define a certain reactive impedance and/or a certain dissipative impedance in the medium of the housing 1, for at least one predetermined frequency band. In order to have the desired effect, the part provided with pores must be manufactured or coated so that the pores in the surface in contact with the water provided in the evaporating tray 10 are closed, whilst the opposite surface has open pores. The pores are obtained by a specific manufacture process and must have, for example, a size greater than 20 micrometers.

In a way of carrying out the present invention, the considered porous material is defined by a material, such as polystyrene polymer, polypropylene and metallic material, for example, aluminum. In the constructions using non-metallic porous material, at least part of the pores of said material is open. However, in the constructions of metallic porous material, the pores of said material are closed.

In another constructive form of the present invention, the noise absorbing means comprises a peripheral ring

40, which is carried by the evaporating tray 10, internally or externally to the peripheral wall 12 thereof, and provided with at least one resonator conduct 20 of the type already previously described. In the construction illustrated in figures 9, 9a, and 17a- 17e, the peripheral ring 40 carries a plurality of resonator conducts 20.

According to the present invention, the peripheral ring 40 presents a certain determined thickness in which at least part of the resonator conducts 20 carried by said peripheral ring 40 can be formed. In a way of carrying out the present invention, the peripheral ring 40 is produced with the evaporating tray 10, upon the injection process thereof. In this process, the resonator conducts 20 can also be produced by injection, all in a single piece. However, it should be understood that each part of evaporating tray 10, peripheral ring 40 and resonator conducts 20 can be obtained, by injection or other appropriate technique, separately or forming a single piece with the parts defined in the same mold and material, the other piece being lately coupled by an appropriate means.

The construction of a peripheral ring 40 allows forming an arrangement of resonator conducts 20 mounted in said peripheral ring 40, after the obtention thereof or also after the mounting of said peripheral ring 40 on the evaporating tray 10, for example, around the peripheral wall 12 thereof. The fitting and retention of the peripheral ring 40 to the evaporating tray 10, as well as of the resonator conducts 20 in said peripheral ring 40, can be obtained, for example, by glue, clamps, welding, mechanical interference, etc.

In the illustrated constructive forms, the peripheral ring 40 is formed separately from the evaporating tray 10, and is then mounted to the latter, externally to the peripheral wall 12 of said evaporating tray 10, for example, adjacent to an upper edge of said peripheral wall 12, at least part of the peripheral ring 40 defining cradles to receive a plurality of resonator conducts 20. The peripheral ring 40, in this construction, superiorly supports each resonator conduct 20. However, it should be understood that this construction is not limitative, but only a way of carrying out the present invention illustrated herein. In another construction, the peripheral ring 40 is medianly provided around the peripheral wall 12 of the evaporating tray 10, the resonator conducts 20 being carried by said peripheral ring 40 medianly or superiorly supported, depending on the length of the resonator conducts 20 and the desired positioning of its upper end, in relation to the upper edge of the evaporating tray 10. In another way of carrying out the present solution, the peripheral ring 40 is defined in a single piece with the evaporating tray 10, for example, from a peripheral flange 10a, radially projecting from the peripheral wall 12 of the evaporating tray 10. In this constructive option, the peripheral flange 10a projects externally and superiorly from said peripheral wall 12. Although not illustrated, the peripheral contour of each resonator conduct 20 can be partially defined by the peripheral wall 12 of the evaporating tray 10 and partially defined by the peripheral ring 40, so that the complementation of said contours define the cross- section of each resonator conduct 20. For this construction, the peripheral ring 40 is conformed to define a portion of the contour of each resonator conduct 20, for example, in the form of a recess, as already previously described, defining an arched portion of the respective resonator conduct 20. As already previously described for the constructions with a tubular sleeve 30, the solution presenting a peripheral ring 40 can be applied to evaporating trays with a conventional shape and already commercialized, and the constructive forms for the resonator conduct 20 are those also already previously discussed. In this case, the peripheral ring 40 carries the resonator conducts 20 wholly conformed therein or, in case of partial conformation, each resonator conduct 20 has part of its contour defined by the adjacent and confronting outer surface portion of the peripheral wall 12 of the evaporating tray 10.

The peripheral ring 40, like the tubular sleeve 30, is retained on the evaporating tray 10 by an appropriate retention means, such as glue, weld, clamps, pins, mechanical interference, etc.

According to the present invention, at least one of the parts of bottom wall 11 and peripheral wall 12 of the evaporating tray 10, of peripheral ring 40 and at least one resonator conduct 20 is defined in a porous material. However, it should be understood that the desired noise attenuation effect can be obtained with at least one of said parts coated with a porous material . It should be further considered that some of said above-described parts can be coated in porous material, while others can be directly produced in porous material presenting the desired noise absorbing characteristics and which define a certain reactive impedance and/or a certain dissipative impedance in the medium of the housing 1, for at least one predetermined frequency band.

In a way of carrying out the present invention, the considered porous material is defined by polystyrene polymer, polypropylene and metallic material, for example, aluminum. In the constructions using non- metallic porous material, at least part of the pores of said material can be open. However, in the constructions using metallic porous material, the pores of said material are closed. In another way of carrying out the present invention, the noise absorbing means is defined by a plurality of pores 50, each pore 50 presenting a first end portion 51, open and turned to a noise generation region in the housing 1 in which the evaporating tray 10 is disposed, and a second end portion 52 , opposite and spaced from the first end portion 51, each pore 50 being dimensioned to present a determined inner section 5 calculated to define a certain reactive impedance and a certain dissipative impedance in the medium of the housing 1, for a determined frequency band. The pores 50 are defined in a porous material, for the formation of at least one of the peripheral wall 12 and

10 bottom wall 11 of the evaporating tray 10, or to be used to coat at least part of said evaporating tray 10, for example, at least one of the peripheral wall 12 and bottom wall 11 of said evaporating tray 10, said porous material being made of a material selected from

15 polystyrene polymer, polypropylene and metallic material, for example, aluminum.

However, it should be understood that the desired noise attenuation effect can be obtained with some of said above-defined parts coated in porous material, while

20 others can be directly produced in porous material presenting the desired noise absorbing characteristics which define a certain reactive impedance and/or a certain dissipative impedance in the medium of the housing 1, for at least one predetermined frequency

25 band.

In the constructions using non-metallic porous material, at least part of the pores of said material can be open. However, in the constructions using metallic porous material, the pores of said material

30. are closed.

Although only some of the constructions discussed above have been illustrated, it should be understood that the concept presented above is not limitative to the illustrations .

35 One of the advantages of the present invention is to increase the attenuation in the region of the housing 1 of the cabinet 3 of refrigeration appliances, in discreet frequencies or in frequency bands in which a deficiency is detected.

The arrangement of resonator conducts 20 of the present invention allows attenuating the noises produced by the compressor and also by the fan (as a result of the blade frequency passage and of the turbulence between the air and these blades) , both mounted in the housing 1 of the refrigeration appliance and also by the refrigeration system, further allowing attenuating the resonances (and their negative effects) which can exist in said housing 1, with a reduced cost in relation to the known prior art .

The constructions in which the resonator conducts 20 are provided in a single piece with the evaporating tray 10 further present the advantage of not adding components or other materials in the housing 1. In these constructions, the provision of resonator conducts 20, each having the respective second end open, also allows each said resonator conduct 20 to act as a defrost water accumulator.

The resonator conducts 20 allow utilizing distinct lengths, enabling the attenuation of several frequencies, or of a broader band. The diameter of each resonator conduct 20 and the shape of the respective cross-section can be selected in accordance with the manufacture process and the required needs for attenuation and dimension. The definition by diameters up to 1 millimeter or larger defines the attenuation behavior of the resonator conduct between totally dissipative (smaller diameters) and totally reactive

(larger diameters) .

The resonator conducts 20 can be distributed along the contour of the peripheral wall 12 so that the lengths thereof present a stepped distribution in the direction desired to attenuate a determined dr random frequency band, when there is no specific frequency region to be attenuated, said frequencies also being randomly present in the housing 1.

Although not illustrated, the obtained noise reductions can reach from 5db to 2OdB, in the tuning frequencies, with the resonator arrangement of the present invention.

Specific features of the present invention are shown in the figures of the enclosed drawings only for convenience, once each feature can be combined with other features in accordance with the invention. Alternative embodiments will be recognized by those skilled in the art, which are intended to be included within the scope of the claims. Accordingly, the above description should be construed as illustrative and not limitative of the scope of the invention. All such obvious changes and modifications are within the patented scope defined by the appended claims .

Claims

1. A resonator arrangement for the cabinet of a refrigeration' appliance, said cabinet (3) defining a housing (1) and carrying, in the latter, a compressor (2) presenting a hermetic casing (2a) and a defrost water evaporating tray (10), comprising: a bottom wall (11) to be seated onto an upper portion of the casing (2a) of the compressor (2) ; and a peripheral wall (12) superiorly projecting from the bottom wall (11) , characterized in that at least one of the peripheral wall (12) and bottom wall (11) of the evaporating tray (10) carries a noise absorbing means (20, 30, 40, 50) turned to a noise generation region in said housing (1) and being dimensioned to define a certain reactive impedance and a certain dissipative impedance in the medium of the housing (1) , for a determined frequency band.

2. The arrangement, as set forth in claim 1, characterized in that the noise absorbing means comprises at least one resonator conduct (20) extending along an extension of the respective wall (11, 12) of the evaporating tray (10) .

3. The arrangement, as set forth in claim 2, characterized in that each resonator conduct (20) presents a first end (21) , which is open and turned to a noise generation region in said housing (1) , and a second end (22) , which is opposite and spaced from the first end (21) , each resonator conduct (20) being dimensioned to present a determined length and a determined diameter, which are calculated to define a certain reactive impedance and a certain dissipative impedance in the medium of the housing (1) , for a determined frequency band.

4. The arrangement, as set forth in claim 3, characterized in that at least one resonator conduct

(20) is at least partially formed in a single piece with an adjacent surface portion of the respective wall (11, 12) of the evaporating tray (10) .

5. The arrangement, as set forth in claim 4, characterized* in J:hat at least part of the length of each resonator; conduct (20) is formed in the thickness of the respective wall (11, 12) of the evaporating tray (10) .

6. The arrangement, as set forth in claim 5, characterized in that the evaporating tray (10) carries a tubular sleeve (30) , the cross-section of the resonator conducts (20) being partially defined in each of the parts of evaporating tray (10) and tubular sleeve (30) .

7. The arrangement, as set forth in claim 6, characterized in that the tubular sleeve (30) presents a surface confronting with an adjacent wall surface

(11, 12) of the evaporating tray (10) , each resonator conduct (20) being defined by a recess (13, 33) produced in at least one confronting surface of tubular sleeve (30) and adjacent wall (11, 12) of the evaporating tray (10) .

8. The arrangement, as set forth in claim 7, characterized in that the tubular sleeve (30) occupies one of the inner and outer positions in relation to the peripheral wall (12) of the evaporating tray (10) .

9. The arrangement, as set forth in claim 8, characterized in that at least one of the parts of peripheral wall (12) and bottom wall (11) of the evaporating tray (10) , of tubular sleeve (30) and at least one resonator conduct (20) is defined in a porous or fibrous material.

10. The arrangement, as set forth in claim 8, characterized in that at least one of the parts of peripheral wall (12) and bottom wall (11) of the evaporating tray (10) , of tubular sleeve (30) and at least one resonator conduct (20) is coated with a porous or fibrous material .

11. The arrangement, as set forth in any one of claims 9 and 10, characterized in that the porous material is defined by a material selected from polystyrene polymer, polypropylene and metallic material.

12. The arrangement, as set forth in claim 11, characterized in that the porous material presents a plurality of closed pores (50) .

13. The arrangement, as set forth in any one of claims 9 and 10, characterized in that the porous material is defined by a material selected from polystyrene polymer and polypropylene, said porous material presenting a plurality of pores (50) , at least part of the pores being (50) open.

14. The arrangement, as set forth in claim 3, characterized in that the evaporating tray (10) carries a peripheral ring (40) provided with a plurality of resonator conducts (20) .

15. The arrangement, as set forth in claim 14, characterized in that the peripheral ring (40) has a thickness, at least part of the resonator conducts (20) being formed in the wall thickness of the peripheral ring (40) .

16. The arrangement, as set forth in claim 14, characterized in that the peripheral ring (40) occupies one of the inner and outer positions in relation to the peripheral wall (12) of the evaporating tray (10) .

17. The arrangement, as set forth in claim 16, characterized in that at least one of the parts of peripheral wall (12) and bottom wall (11) of the evaporating tray (10) , of peripheral ring (40) and at least one resonator conduct (20) is defined in a porous or fibrous material .

18. The arrangement, as set forth in claim 16, characterized in that at least one of the parts of peripheral wall (12) and bottom wall (11) of the evaporating tray (10) , of peripheral- ring (40) and at least one resonator conduct (20) is coated with a porous or fibrous material .

19. The arrangement, as set forth in any one of claims 17 and 18, characterized in that the porous material is defined by a material selected from polystyrene polymer, polypropylene and metallic material.

20. The arrangement, as set forth in claim 19, characterized in that the porous material presents a plurality de closed pores (50) .

21. The arrangement, as set forth in any one of claims 17 and 18, characterized in that the porous material is defined by a material selected from polystyrene polymer and polypropylene, having at least part of the pores open.

22. The arrangement, as set forth in claim 3, characterized in that the resonator conducts (20) are straight in at least part of their extension.

23. The arrangement, as set forth in claim 22, characterized in that at least two resonator conducts (20) are parallel to one another.

24. The arrangement, as set forth in claim 22, characterized in that at least one of the resonator conducts (20) is vertical.

25. The arrangement, as set forth in claim 22, characterized in that at least one of the resonator conducts (20) is horizontal.

26. The arrangement, as set forth in claim 22, characterized in that the resonator conducts (20) are provided inclined in relation to the axis of the wall in which they are provides .

27. The arrangement, as set forth in claim 3, characterized in that the second end (22) of each resonator conduct (20) is closed.

28. The arrangement, as set forth in claim 3, characterized in that at least part of the resonator conducts (20) presents a constant cross-section along their length.

29. The arrangement, as set forth in claim 3, characterized in that at least part of the resonator conducts (20) presents a variable cross-section along their length.

30. The arrangement, as set forth in claim 29, characterized in that at least part of the resonator conducts (20) presents a stepped cross-section.

31. The arrangement, as set forth in claim 29, characterized in that at least part of the resonator conducts (20) presents a conical cross-section.

32. The arrangement, as set forth in claim 29, characterized in that at least part of the resonator conducts (20) presents an exponential cross-section.

33. The arrangement, as set forth in any one of claims 28-32, characterized in that at least part of the resonator conducts (20) has one of the circular and polygonal cross-sections.

34. The arrangement, as set forth in claim 1, characterized in that the noise absorbing means presents a plurality of pores (50) .

35. The arrangement, as set forth in claim 34, characterized in that each pore (50) presents a first end portion (51) , which is open and turned to a noise generation region in said housing (1) , and a second end portion (52) , which is opposite and spaced from the first end (21) , each pore (50) being dimensioned to present a determined inner section calculated to define a certain reactive impedance and a certain dissipative impedance in the medium of the housing (1) for a determined frequency band.

36. The arrangement, as set forth in claim 34, characterized in that at least one of the peripheral wall (12) and bottom wall (11) of the evaporating tray (10) is defined in a porous or fibrous material.

37. The arrangement, as set forth in claim 34, characterized in that at least one of the peripheral wall (12) and bottom wall (11) of the evaporating tray (10) is coated with a porous or fibrous material.

38. The arrangement, as set forth in any one of claims 36 and 37, characterized in that the porous material is defined by a material selected from polystyrene polymer, polypropylene and metallic material.

39. The arrangement, as set forth in claim 38, characterized in that the pores (50) are closed.

40. The arrangement, as set forth in any one of claims 36 and 37, characterized in that the porous material is defined by a material selected from polystyrene polymer and polypropylene, having at least part of the pores (50) open.

41. The arrangement, as set forth in claim 1, characterized in that the noise absorbing means comprises at least one resonator conduct (20) extending along an extension of the respective wall (11, 12) of the evaporating tray (10) and presenting a plurality of pores (50) .

42. The arrangement, as set forth in claim 41, characterized in that each resonator conduct (20) presents a first end (21) , which is open and turned to a noise generation region in said housing (1) , and a second end (22) , which is opposite and spaced from the first end (21) , each resonator conduct (20) being dimensioned to present a determined length and a determined diameter, which are calculated to define a certain reactive impedance and a certain dissipative impedance in the medium of the housing (1) , for a determined frequency band.

43. The arrangement, as set forth in claim 41, characterized in that at least one of the parts of peripheral wall (12) and bottom wall (11) of the evaporating tray (10) and at least one resonator conduct (20) is defined in a porous or fibrous material .

44. The arrangement, as set forth in claim 41, characterized in that at least one of the parts of peripheral wall (12) and bottom wall (11) of the evaporating tray (10) and at least one resonator conduct (20) is coated with a porous or fibrous material .

45. The arrangement, as set forth in any one of claims 42 and 43, characterized in that the porous material is defined by a material selected from polystyrene polymer, polypropylene and metallic material.

46. The arrangement, as set forth in claim 44, characterized in that the porous material presents a plurality of closed pores (50) .

47. The arrangement, as set forth in any one of claims 42 and 43, characterized in that the porous material is defined by a material selected from polystyrene polymer and polypropylene, having at least part of the pores (50) open.