ACOUSTIC FILTER"

Field of the invention

The present invention refers to an acoustic filter for hermetic compressor and, more particularly, a suction acoustic filter including a nozzle specially for minimizing work fluid suction at high temperature. The present invention further relates to a suction line of hermetic compressor, which includes such suction acoustic filter including a nozzle specially for minimizing work fluid suction at high temperature.

Generally, the main purpose of the invention in question is related to functional optimization of the hermetic compressor minimizing the quantity of work fluid at high temperature sucked to the inside of the compression mechanism (piston- cylinder set).

Background of the Invention

As it is known by technicians on the art, hermetic compressor comprises electromechanical devices capable of compress a work fluid by successive alteration of the internal volume of a compression chamber. Hermetic compressors are mainly applied in cooling systems.

This successive alteration of volume is carried out, in reciprocating hermetic compressors, by means of a compression mechanism fundamentally integrated by a piston-cylinder set, in which said piston is capable of be reciprocating displaced, on axial direction, inside the cylinder, altering the volume of it. It should be noted that said compression mechanism is enclosed inside the hermetic housing of the compressor.

Due to piston reciprocating movement, it can be stated that a reciprocating hermetic compressor operates in suction and exhaust reciprocating cycles of the work fluid.

Among the multiple functional variables existing in hermetic compressors, and in view of the scope of the present application, there are discussed two of these functional variables. The first functional variable discussed refers to the temperature of the work fluid sucked by the compression mechanism, in which as higher the temperature of this fluid, lower will be the yield of the compressor. This functional variable is also broadly known by technicians on the art, besides being broadly described by technical specialized literature.

The current state of the art comprises multiple solutions especially for optimizing the first functional variable, this is, especially for cooling the work fluid temperature sucked by the compression mechanism. Document BRPI1 100416, for example, describes the application of a pre evaporator inside the hermetic house of the compressor whose main objective is reducing the compression mechanism temperature, or still, the work fluid temperature sucked by the compression mechanism.

The second functional variable now approached refers to the noise level generated during hermetic compressor operation, noise that can come from different sources. The reciprocating between suction and exhaust cycles itself, during the compressor operation, is characterized by generating vibrations and pulsing noises extremely undesired.

The current state of the art comprises multiple solutions especially for optimizing the second functional variable, this is, especially for attenuation of the pulsing noise generated by the suction and exhaust cycles, and smog the solutions already known, it is highlighted the one known with suction acoustic filter. Suction acoustic filters are broadly known by technicians on the art, beyond being broadly described in specific technical literature. Generally, a suction acoustic filter comprises a chamber that, disposed in some part of the suction line, defines a broad volume (related to the volume of the suction line part) capable of minimizing the pulsing effects referred to the reciprocating between the suction cycles. Such functional principle is broadly known and applied in reciprocating hermetic compressors. Although the functional principle of a suction acoustic filter is invariable, the constructive possibilities and the assembling possibilities are wide. Embodiments are known of sealed suction acoustic filters (applied on hermetic or direct suction lines), and non-sealed suction acoustic filters (applied in equalized or indirect suction lines, and also applied on semi direct suction lines).

Different models of suction acoustic filters, with different purposes, are illustrated on figures 1 , 2 and 3.

The suction acoustic filter schematically illustrated on figure 1 is about a usual embodiment pertaining to the current state of the art. Such acoustic filter is totally integrated by a pre chamber A and a main chamber B. Said pre chamber A comprises a fluid inlet area A1 and a fluid outlet area A2, while main chamber B comprises a fluid inlet tubing B1 and a fluid outlet tubing B2. As illustrated, the fluid outlet area A2 of pre chamber A and the beginning of the fluid inlet tubing B1 of main chamber B confuses between them, this is because both are fluidly connected. Generally, said pre chamber A has just the function of fluid confinement, while main chamber B has the function of pulsing attenuation. Thus, is possible to say that suction acoustic filter schematically illustrated on figure 1 do not comprises any feature, characteristic or implement for optimizing the functional variable related to the work fluid temperature sucked by the compression mechanism.

The suction acoustic filter illustrated on figure 2 is about the suction acoustic filter described on document JP2001055976, where it is described a suction acoustic filter defined by an inlet C1 , an internal volume C2 and an outlet C3, being such acoustic filter specially cooperating with an extensor D coming from the suction passer. One of the main ideas foreseen on document JP2001055976 is that the suction acoustic filter gets (be fed) work fluid free from eventual turbulences existing on the environment defined inside the hermetic housing of the compressor. It is also not said any feature, aspect or implement to optimizing the functional variable related to the work fluid temperature sucked by the compression mechanism.

The suction acoustic filter illustrated on figure 3 is about the suction acoustic filter described on document KR20020027794, where it is described a suction acoustic filter defined by a nozzle F1 , an inlet pipe F4, an internal volume F2 and an outlet F3, being the nozzle F1 convergent, this is, with the inlet area greater than the outlet area. Beyond the examples listed above, and having in mind the current understandings, it is known that the current state of the art lacks of a unified solution that, implemented in suction acoustic filters, be the optimization of the two functional variables before explained. It is based on this scenario that arises the invention in question.

Objectives of the Invention

Therefore, it is one of the objectives of the invention in question reveal a suction acoustic filter that, including a different nozzle, makes possible the suction and trapping of the work fluid on a temperature lower than the temperature of the work fluid existing on the internal environment of the hermetic housing, reaching the main majority of the observed benefits in systems capable of cooling the temperature of the work fluid sucked by compression mechanism. It is also one of the objectives of the invention in question that the suction acoustic filter including a nozzle reaches maximum optimization when related to pulsing noise attenuation generated by suction and exhaust cycles.

Additionally, it is one of the objectives of the invention in question reveal a suction line including a suction acoustic filter (including a nozzle) capable of optimizing the functioning of the hermetic compressor and, specially, capable of optimizing the efficiency of the hermetic compressor from the temperature reduction of the work fluid sucked by the compression mechanism and the reduction of the noise generated by the reciprocation between suction and exhaust cycles.

In this context, it is one of the main objectives of the invention in question that these optimizations are reached simply and non-costly, without the need to include further devices and/or systems.

Summary of the Invention

All the objectives of the invention in question are reached by means of a suction acoustic filter, which comprises at least one inlet path, at least one acoustic chamber, at least one outlet path and at least one nozzle fluidly connected to at least one inlet path and having at least one fluid inlet and at least one fluid directing area for the inlet path of the suction acoustic filter. According to the invention in question, said nozzle comprises at least one part of divergent section related to the main flow of outflow, being this part situated between at least one fluid inlet area and at least one fluid directing area.

Also according to the invention in question, it is revealed a suction line including a suction acoustic filter integrated by at least one suction passer and at least one suction acoustic filter comprised by at least one inlet path, at least one acoustic chamber, at least one outlet path and at least a nozzle fluidly connected to at least one inlet path and having at least one fluid inlet area and at least one fluid directing area for the inlet path of the suction acoustic filter. Said nozzle of the suction acoustic filter comprises at least one part of divergent section related to the main flow of outflow, being this part situated between at least one fluid inlet area and at least one fluid directing area.

According to the invention in question, the suction passer outlet is adjacent disposed to the fluid inlet area of the suction acoustic filter nozzle.

Brief Description of the Drawings

The invention in question will be detailed based on the following listed figures, in which:

Figure 1 illustrates, schematically, a suction acoustic filter pertaining to the current state of the art;

Figure 2 illustrates the suction acoustic filter detailed on document

JP2001055976 (state of the art);

Figure 3 illustrates the suction acoustic filter detailed on document KR20020027794 (state of the art);

Figure 4 illustrates the suction acoustic filter including a nozzle, according to the preferred embodiment of the invention in question;

Figure 5 illustrates the suction acoustic filter including a nozzle, according to one alternate embodiment of the invention in question;

Figure 6 illustrates, in enlarged detail, the nozzle, according to the invention in question.

Figures 7 and 8 illustrates other alternatives for the suction acoustic filter including a nozzle, according to the invention in question;

Figures 9 and 10 illustrates, schematically, work "situations" in which the suction acoustic filter including a nozzle is exposed; and

Figure 1 1 A illustrates a comparative graphic of temperature between the suction acoustic filter including the nozzle according to the preferred embodiment of the invention in question (see references on figure 1 1 B) and a suction acoustic filter already established on the literature (see references on figure 1 1 C).

Detailed Description of the Invention

As already mentioned, the current state of the art comprises some solutions dedicated to the cooling of the compression mechanism, or still, cooling means of the work fluid sucked by the compression mechanism. Such solutions of cooling, so ever are capable of maintaining said compression mechanism on a lower temperature, involve energetic costs, costs which can also damage the compressor efficiency.

Before the detailing of the embodiment of the inventions in question, it is important to define, punctually, the meaning of the expressions "main flow of outflow" and "pulsing reflux", following used as descriptive referential.

Main flow of outflow (FPE): Gas flow going from suction passer until the compression chamber.

Pulsing reflux (RP): Gas flow that return from the compression chamber to the internal of the suction acoustic filter and, eventually, outside the same due to the valves dynamic.

Thus, it is great the merit of the invention in question to keep the compression mechanism of the hermetic compressor to a lower temperature without being necessary to use the cooling means.

So, it is highlighted the invention in question because it reveals a mean capable of guarantee that just (or at least mainly) the work fluid directly coming from the suction passer of the compressor, whose fluid comes from the evaporation line (which presents lower temperature that the work fluid enclosed on the internal environment defined by the hermetic housing of compressor) be sucked by the compression mechanism. Generally, such means are fundamentally composed by a nozzle that, preferentially (but not limitative) disposed on the external portion of the suction acoustic filter and fluidly connected to the inlet path of said suction acoustic filter, is capable of act as a kind of work fluid concentrator directly coming from the suction passer of compressor and, simultaneously, with a kind of barrier to suction of the work fluid enclosed on the internal environment defined by the compressor hermetic housing. In other words, said nozzle ends acting as a "cold fluid trap", blocking (or making difficult) that said cold fluid (coming directly from the suction passer of the compressor) to be homogeneous, thermally, with the work fluid enclose on the internal environment defined by the hermetic housing of the compressor.

The objectives of the invention in question are more explored based on the illustrative figures 4, 5, 6, 7, 8, 9 and 10.

In this sense, the preferred embodiment of the invention in question (figure 4) has a suction acoustic filter 1 fundamentally formed by an inlet path 11 , a main chamber 12 with functions of attenuating fluid flow pulsing (and, consequently, noise attenuation), and an outlet path 13, which is functionally liked with the compression mechanism head (not illustrated).

It worth to say that said suction acoustic filter 1 comprises, roughly, a suction acoustic filter conventional and also the generic. This means that the core of the invention in question (detailed as follows) can be applied in several models and constructions of suction acoustic filters, since such filter comprises at least one inlet path 11 , at least one main chamber 12 and at least one outlet path 13. Preferably, and as illustrated on figure 4, the inlet path 11 and the outlet 13 are spaced apart, being said inlet path 11 disposed laterally on the suction acoustic filter 1 .

Said suction acoustic filter 1 comprises a nozzle 2 fluidly connected to at least one inlet path 11 and having a fluid inlet area 21 and a fluid directing area 22 for the inlet path 11 of the suction acoustic filter 1.

Moreover, and according to the invention in question, the nozzle 2 of said suction acoustic filter 1 comprises a part of divergent section 23 related to the main flow of outflow (FPE). As illustrated on figures 4, 5 and 6, the part of divergent section 23 - related to the main flow of outflow (FPE) - comprises the own fluid inlet 21 , which have a smaller area than the fluid directing area 22. Particularly according to the preferential embodiment of the invention, the inlet area of the nozzle 21 is, at maximum, 50% lower than the fluid directing area 22.

In figures 7 and 8 - that illustrates possible alternate embodiments - the part of divergent section 23 - related to the main flow of outflow (FPE) - comprises kind of a narrow or choke related to the pulsing reflux direction (RP), where the fluid inlet area 21 is larger than the fluid directing area 22.

The existence of the divergent section part 23 - related to the main flow of the outflow (FPE) - is on the own fluid inlet area 21 of nozzle 2 or between the fluid inlet area 21 and the fluid directing area 22 - it is about one of the most preponderant features of the invention in question, after all, this is the part where the area suffers a reduction - related to the pulsing reflux (RP) - that is responsible by the work fluid trapping directly coming from the compressor suction passer and that defines the barrier to the suction of the work fluid enclosed on the internal environment defined by the hermetic housing of the compressor.

As illustrated on figure 9, it can be stated that nozzle 2 defines a volume with at least one divergent part considering the direction of the main flow outflow (FPE). This way, the fluid coming from the suction passer is directed and stored inside the nozzle 2, for, then, be converted in "suction fluid" FS, which enters on the suction acoustic filter 1 by the inlet path 1 1 whose fluid directing area 22 of the nozzle 2 communicates. At the most, it is further verified that the "housing fluid" FC is mainly blocked from entering on the nozzle 2.

As illustrated on figure 10, it can be said that the nozzle 2 defines a volume with at least one convergent part, now considering the direction of the pulsing reflux (RP). This ends blocking or making difficult fluid outlet at low temperature of said pulsing reflux (RP) for the environment out of the nozzle 2.

As the suction dynamic of reciprocating hermetic compressors is fundamentally constant (pulsed in high frequency), there is no sufficient time so the temperature of the "suction fluid" FS increase related to the temperature of the main flow fluid of outflow (FPE). This way, said volume of nozzle 2 ends acting as work fluid accumulator at "low" temperature.

The potentiation of this thermal dynamic, by the suction line including a suction acoustic filter here revealed, is other great merit of the invention in question.

According to the suction line including suction acoustic filter here revealed, the suction passer 3 of the hermetic compressor 31 , shown on figure 4, have its adjacent outlet to the fluid inlet area 21 of nozzle 2 of the suction acoustic filter 1 . Evidently, when closer and aligned the suction passer 3 of the hermetic compressor and the fluid inlet area 21 of the nozzle of the suction acoustic filter 1 , greater will be the work fluid concentration effects directly coming from the evaporation line, and better will be the barrier to the work fluid suction enclosed on the internal environment defined by the hermetic housing of the compressor.

Related to the constructive features more predominant of the preferred embodiment of the suction acoustic filter 1 , it remains to emphasizes that - preferentially, but not limitative - said nozzle 2 comprises a modular body to the suction acoustic filter 1 , this is, comprises an independent body related to the suction acoustic filter 1 . On this embodiment, the nozzle 2 is fixed to the suction acoustic filter 1 by a hermetic fixing means, as for example, a sealing and glutinous resin.

Alternatively, it is observed that the nozzle 2 could comprise also a body integrated with the suction acoustic filter 1 , this is, both bodies are part of the same monoblock. In this alternative embodiment, such monoblock could be made by thermoforming processes, for example.

Additionally, and considering that the preferred embodiment of the suction acoustic filter 1 foresee inlet paths 1 1 and outlet 13, where the inlet path 1 1 is disposed laterally on the suction acoustic filter 1 , it is worth to say that - preferably, but not limitative - the fluid inlet 21 of the nozzle 2 is laterally disposed related to said suction acoustic filter 1 .

Now related to the suction line itself, it remains to emphasize that the suction passer outlet 3 can be directly or indirectly aligned to the fluid inlet area 21 of the nozzle 2 of the suction acoustic filter 1 , in a way that on the indirect option, it is foreseen the use of an extensor pipe (not illustrated).

Preferentially, said nozzle 2 should have a maximum volume approximate the same as half the volume displaced from the compressor, because this would be the maximum fluid volume accumulated during a cycle.

Figure 1 1 A, that refers to the specific areas illustrated on figures 1 1 B and 1 1 C shows a graphic where is demonstrated that the suction acoustic filter 1 with nozzle 2 including a divergent section part 23 is more effective thermodynamically than the acoustic filter belonging to the current state of the art illustrated on figure 1 1 C, because the temperature of the fluid on the outlet of the acoustic filter is lowered.

Having being described and illustrated several embodiments of the invention in question, it should be understood that the protection scope in question can englobe other possible variations, in which are limited just by the claims, here included the possible equivalent means.