JP2020153649A - Refrigerating machine - Google Patents

Abstract

To properly attenuate noise in a refrigerating machine by a compact acoustic damper with a simpler configuration.SOLUTION: A refrigerating machine 100 includes: a compressor 101 for compressing a refrigerant; a condenser 102 for condensing the refrigerant compressed by the compressor 101; an evaporator 103 for evaporating the refrigerant condensed by the condenser 102; a plurality of pipes (refrigerant pipes 106a, 106b, 106c and hot gas bypass pipe 109) for connecting the compressor 101, the condenser 102 and the evaporator 103; and an acoustic damper 1A disposed in the hot gas bypass pipe 109 as a gas fluid pipe through which a gas fluid flows, among the plurality of pipes. The acoustic damper 1A has a housing (acoustic damper body) forming a passage for taking air vibration generated in the hot gas bypass pipe 109, and a vibration portion having a prescribed spring constant, mounted on an inner face of an end plate for closing the passage, and vibrated by air vibration.SELECTED DRAWING: Figure 1

Description

The present invention relates to a refrigerator equipped with an acoustic damper.

Conventionally, a technique relating to a device for attenuating vibration generated at a vibration source is known. For example, Patent Document 1 describes a plurality of quarters coupled to an air supply unit, a fuel supply unit, and a diluent supply unit on the upstream side of the combustor in order to attenuate combustion vibration in a gas turbine combustor. A gas turbine system including a one-wave combustor and a control device for adjusting the combustor is disclosed. In this gas turbine system, the quarter-wavelength resonator is a variable-shaped resonator, and the pressure vibration in the combustor is detected by a pressure sensor, and the shape of the variable-shaped resonator is determined based on the detected pressure. By adjusting, the vibration of the desired frequency is attenuated.

Japanese Unexamined Patent Publication No. 2011-52954

By the way, as a vibration generation source, in addition to the combustor of the gas turbine described in Patent Document 1, there is a refrigerator provided with a compressor, a condenser and an evaporator. In the refrigerator, when the compressor operates, the flow rate fluctuates periodically according to the movement of the blades, the number of blades of the diffuser, and the like, and noise due to pressure pulsation, so-called NZ sound, is generated. The generation of NZ sound has the property of having a specific frequency characteristic. Then, the NZ sound may resonate with the fluid sound in the piping of the refrigerator, and the noise may be amplified. Therefore, it is required to suppress the resonance between the NZ sound and the fluid sound in the piping.

Therefore, it is conceivable to attach an damping device as described in Patent Document 1, that is, an acoustic damper, to the piping of the refrigerator to attenuate the vibration of a desired frequency. However, in order to aim at damping the vibration of a desired frequency, the tuning frequency is determined by the length of the wavelength tube of the acoustic damper. Therefore, as in the gas turbine system described in Patent Document 1, the variable shape type The structure of the acoustic damper tends to be complicated, such as by adopting the acoustic damper of. Further, in order to satisfactorily attenuate the vibration, the volume of the acoustic damper tends to be large. As a result, space for mounting the acoustic damper tends to be insufficient. Therefore, a small acoustic damper with a simpler configuration is required.

The present invention has been made in view of the above, and an object of the present invention is to satisfactorily attenuate noise in a refrigerator by a small acoustic damper with a simpler configuration.

In order to solve the above-mentioned problems and achieve the object, the present invention comprises a compressor for compressing a refrigerant, a condenser for condensing the refrigerant compressed by the compressor, and the condenser condensed by the condenser. At least of the evaporator for evaporating the refrigerant, the compressor, the plurality of pipes connecting the condenser and the evaporator, and the gas fluid pipe through which the gas fluid flows and the discharge pipe of the compressor among the plurality of pipes. The acoustic damper includes an acoustic damper provided in any one of them, and the acoustic damper has an acoustic damper main body forming a passage for taking in air vibration generated in the pipe, and a predetermined spring constant, and closes the passage. It is characterized by having a vibrating portion attached to the inner surface of the end plate to be vibrated by the air vibration.

With this configuration, the vibration of the acoustic damper can be absorbed by the vibrating portion having a predetermined spring constant, and the acoustic boundary condition of the acoustic damper can be changed. As a result, the intrinsic value of the resonance frequency of the acoustic damper can be changed, so that the acoustic damper can satisfactorily attenuate the fluid sound of a desired frequency in the gas fluid pipe through which the gas fluid of the refrigerator flows and the discharge pipe of the compressor. Is possible. Therefore, it is possible to suppress the resonance between the fluid sound in the gas fluid pipe and the discharge pipe of the compressor and the NZ sound generated in the compressor. Further, since the sound pressure level can be reduced by changing the intrinsic value of the resonance frequency of the acoustic damper, it is possible to reduce the size of the acoustic damper aiming at the vibration damping of the same resonance frequency. Therefore, according to the present invention, noise in the refrigerator can be satisfactorily attenuated by a small acoustic damper with a simpler configuration.

Further, the gas fluid pipe provided with the acoustic damper is preferably a hot gas bypass pipe that bypasses the refrigerant from the evaporator to the condenser. With this configuration, the fluid noise in the hot gas bypass pipe between the evaporator and the condenser can be well attenuated.

Further, the vibrating portion is attached to the acoustic damper main body and has a bellows shape in which a cavity communicating with the passage is formed inside, and the end plate is attached to the vibrating portion to form the cavity and the passage. It is preferable to block the. With this configuration, the bellows-shaped vibrating portion can be vibrated by air vibration together with the end plate that closes the passage. That is, when the air vibration resonates in the acoustic damper, the vibrating portion vibrates and the end plate serves as the impedance boundary of the acoustic, so that the acoustic boundary condition of the acoustic damper can be changed.

Further, the acoustic damper is attached to the end plate via the vibrating portion, and further has a vibrating plate in the passage, and the vibrating portion is an inner surface of the end plate and the diaphragm. It is preferable to have a plurality of elastic members provided between the two. With this configuration, it is possible to vibrate a vibrating portion having a plurality of elastic members together with a diaphragm arranged in the passage by air vibration. That is, when the air vibration resonates in the acoustic damper, the vibrating portion vibrates and the diaphragm becomes the impedance boundary of the acoustic, so that the acoustic boundary condition of the acoustic damper can be changed.

Further, the elastic member preferably has a shape in which polygonal pyramid trapezoids are continuously stacked. With this configuration, the spring constant of the vibrating portion can be easily adjusted, and the vibrating portion can have a simple configuration.

Further, the predetermined spring constant is preferably 10 N / mm or more and 100 N / mm or less. With this configuration, the vibrating portion can be deformed by the action of a relatively small load. That is, the vibrating portion can be deformed in response to a minute vibration to absorb the vibration.

Further, it is preferable that the vibrating portion has a continuous sedimentary layer made of one or more kinds of materials. With this configuration, the vibrating portion having a predetermined spring constant can be easily obtained by forming the vibrating portion by laminated molding.

FIG. 1 is a schematic configuration diagram showing a refrigerator according to the first embodiment. FIG. 2 is an explanatory diagram schematically showing an acoustic damper. FIG. 3 is an explanatory diagram showing an example of the load displacement characteristic of the vibrating portion. FIG. 4 is an explanatory diagram showing an example of an analysis result of the relationship between the resonance frequency and the sound pressure level in the acoustic damper according to the first embodiment. FIG. 5 is an explanatory diagram showing an example of the load displacement characteristic of the vibrating portion. FIG. 6 is an explanatory diagram showing a specific example of the vibrating portion. FIG. 7 is an explanatory diagram schematically showing an acoustic damper included in the refrigerator according to the second embodiment. FIG. 8 is an explanatory diagram showing a specific example of the vibrating portion of the acoustic damper shown in FIG. FIG. 9 is an explanatory diagram showing a specific example of a main part of the vibrating portion shown in FIG.

Hereinafter, embodiments of the refrigerator according to the present invention will be described in detail with reference to the drawings. The present invention is not limited to this embodiment.

[First Embodiment]
FIG. 1 is a schematic configuration diagram showing a refrigerator according to the first embodiment. The refrigerator 100 according to the first embodiment is, for example, a part of an air conditioner for adjusting the temperature, humidity, etc. of a building or a factory, or an air conditioner for cooling a freezing room. The refrigerator 100 is a device that supplies cold water or air to an installed building, factory, or freezer to cool the installed building, factory, or freezer. The refrigerator 100 includes a compressor 101, a condenser 102, an evaporator 103, and an intercooler 104.

The compressor 101 and the condenser 102 are communicated with each other by a refrigerant pipe 106a (discharge pipe) through which the refrigerant flows. Further, the condenser 102 and the evaporator 103 are communicated with each other by a refrigerant pipe 106b through which a refrigerant flows. The intercooler 104 is interposed in the refrigerant pipe 106b. Further, the evaporator 103 and the compressor 101 are communicated with each other by a refrigerant pipe 106c through which a refrigerant flows. That is, the compressor 101, the condenser 102, the evaporator 103, and the intercooler 104 are provided in the circulation path 106 for circulating the refrigerant through the refrigerant pipes 106a, 106b, and 106c. Further, in the path of the refrigerant pipe 106b, a hot gas bypass valve 107 is provided on the upstream side of the intercooler 104, and a hot gas bypass valve 108 is provided on the downstream side. Further, the condenser 102 and the evaporator 103 are provided with a hot gas bypass pipe 109 that bypasses and supplies high-temperature refrigerant gas from the evaporator 103 to the condenser 102 without passing through the circulation path 106. Further, the hot gas bypass pipe 109 is provided with an adjusting valve 110 for adjusting the flow rate of the refrigerant gas.

The compressor 101 is configured as a turbo compressor that compresses the refrigerant by the rotational movement of the impeller. That is, the refrigerator 100 is a so-called turbo chiller. The compressor 101 as a turbo compressor has a compression unit 112 driven by an electric motor 111. The compression unit 112 includes a two-stage compression system in which two impellers coaxially driven by the electric motor 111 are provided, and a single-stage compression system in which one impeller is rotationally driven by the electric motor 111. When the compression unit 112 is two-stage compression, the gas-phase refrigerant sent from the evaporator 103 to the compressor 101 is compressed by the first-stage compression unit and then further compressed by the second-stage compression unit to obtain pressure. And the temperature rises and is sent (discharged) to the condenser 102 via the refrigerant pipe 106a. On the other hand, when the compression unit 112 is single-stage compression, the gas-phase refrigerant sent from the evaporator 103 to the compressor 101 is compressed by the compression unit 112, and the pressure and temperature rise while passing through the refrigerant pipe 106a. It is sent to the condenser 102.

The condenser 102 is connected to a cooling water pipe 121 to which a refrigerant cooling fluid (for example, water) is supplied. The gas-phase refrigerant sent from the compressor 101 to the condenser 102 exchanges heat with the refrigerant cooling fluid supplied by the cooling water pipe 121 and condenses, that is, heat is discharged to the refrigerant cooling fluid and liquefied, and the refrigerant pipe is used. It is sent to the evaporator 103 via 106b. The cooling water pipe 121 is provided with a pump 122 and a cooling water supply unit 123. The pump 122 circulates the cooling water in the cooling water pipe 121. The cooling water supply unit 123 supplies the cooling water to the cooling water pipe 121, and recovers the cooling water that has exchanged heat with the refrigerant.

The evaporator 103 is connected to a chilled water pipe 131 to which a cooling medium (water in this embodiment) is supplied. The liquid-phase refrigerant sent from the condenser 102 to the evaporator 103 evaporates by exchanging heat with the cooling medium supplied by the chilled water pipe 131. In this process, the temperature of water drops by dissipating heat to the liquid-phase refrigerant. As a result, the water becomes cold water. Then, the liquid phase refrigerant that has exchanged heat with water evaporates to become a gas phase refrigerant, and is sent to the compressor 101 via the refrigerant pipe 106c. The chilled water pipe 131 is provided with a pump 132 and a chilled water consuming unit 134. The pump 132 circulates water (cold water) in the cold water pipe 131. The cold water consumption unit 134 supplies cold water to the cold water pipe 131, exchanges heat with the refrigerant, and recovers the cooled cold water. The cold water consumption unit 134 uses the collected cold water to cool the air of equipment in which an air conditioner (not shown) is installed. A fluid other than water can also be used as the cooling medium.

The intercooler 104 separates the refrigerant that has passed through the hot gas bypass valve 107 into a liquid phase and a gas phase after being liquefied in the condenser 102. Further, the intercooler 104 maintains a constant pressure difference between the condenser 102 and the evaporator 103, and evaporates a part of the liquid phase refrigerant to increase the latent heat in the evaporator 103. Is. Further, in the intermediate cooler 104, the gas-phase refrigerant and the liquid-phase refrigerant that have not been completely condensed by the condenser 102 are introduced as a gas-liquid two-phase flow fluid, and the gas-phase refrigerant and the liquid-phase refrigerant are introduced. It functions as a gas-liquid separator that separates the and, and the separated gas-phase refrigerant is sent to the compressor 101, and the liquid-phase refrigerant is sent to the hot gas bypass valve 108. The refrigerant that has passed through the hot gas bypass valve 108 is sent to the evaporator 103.

The hot gas bypass valve 107 is a mechanism for expanding the refrigerant liquefied by the condenser 102. Specifically, the refrigerant is depressurized from the condensation pressure to the intermediate pressure. The refrigerant decompressed by the hot gas bypass valve 107 is supplied to the intercooler 104.

The hot gas bypass valve 108 is a mechanism for expanding the liquid refrigerant (saturated liquid refrigerant) that has passed through the intercooler 104. Specifically, the refrigerant is depressurized from the intermediate pressure to the vapor pressure. The refrigerant decompressed by the hot gas bypass valve 107 is supplied to the intercooler 104.

The refrigerator 100 has the above configuration. The refrigerator 100 is not limited to the above configuration. The refrigerator 100 may include a compressor 101, a condenser 102, and an evaporator 103, and the piping configuration, pump arrangement, hot gas bypass valve arrangement, and the like may be various. it can.

Next, a main part of the refrigerator 100 according to the first embodiment will be described. In the refrigerator 100, when the compressor 101 operates, the flow rate fluctuates periodically according to the movement of the blades, the number of blades of the diffuser, and the like, and noise due to pressure pulsation, so-called NZ sound, is generated. The generation of NZ sound has the property of having a specific frequency characteristic. Then, the NZ sound may resonate with the fluid sound in each pipe included in the circulation path 106 of the refrigerator 100, and the noise may be amplified. Therefore, it is required to suppress the resonance between the NZ sound and the fluid sound in each pipe.

Therefore, in addition to the above configuration, the refrigerator 100 includes an acoustic damper 1A provided in each of the pipes included in the circulation path 106 through which the refrigerant gas (gas fluid) flows. The acoustic damper 1A is a side branch type acoustic damper.

FIG. 2 is an explanatory diagram schematically showing an acoustic damper. In the present embodiment, the acoustic damper 1A is attached to the outer surface of the hot gas bypass pipe 109 as shown in FIGS. 1 and 2. The acoustic damper 1A has a housing 2 as an acoustic damper main body extending along an axial direction which is an extension direction of the hot gas bypass pipe 109 outside the hot gas bypass pipe 109 as a vibration generation source. The housing 2 is formed in a straight pipe shape and is adhered to the outer surface of the hot gas bypass pipe 109. The housing 2 as the main body of the acoustic damper is a so-called quarter wavelength tube.

In the acoustic damper 1A, a passage 3 forming an acoustic portion is formed inside the housing 2. The passage 3 is formed by connecting in a series, and one end thereof is configured as an inlet (not shown) for taking in air vibration generated by a vibration source. The inlet is provided so as to open toward the outer surface of the hot gas bypass pipe 109. The hot gas bypass pipe 109 is formed with through holes (not shown) composed of a plurality of small holes for passing air vibration (pressure wave) due to the refrigerant gas flowing inside to the outside at a position facing the inlet. , Air vibration is taken into the passage 3 from the inlet through this through hole. Further, in the first embodiment, the other end of the passage 3 is open.

In the first embodiment, the acoustic damper 1A includes a vibrating portion 50 and an end plate 52. The vibrating portion 50 is fixed to the surface of the housing 2 opposite to the side in contact with the hot gas bypass pipe 109. Further, the vibrating portion 50 has a cavity 5 (see FIG. 5) inside, and the passage 3 of the housing 2 and the cavity 5 communicate with each other. As a result, the air vibration taken into the passage 3 propagates to the cavity 5. The end plate 52 is formed of a material having a predetermined rigidity, and is attached to a surface of the vibrating portion 50 opposite to the surface on the side in contact with the housing 2. As a result, the end plate 52 is configured as a terminal that closes the downstream side of the propagation of air vibration and serves as a resistance to air vibration.

FIG. 3 is an explanatory diagram showing an example of the load displacement characteristic of the vibrating portion. The vibrating portion 50 is formed of an elastically deformable material. As shown in FIG. 3, the spring constant of the vibrating portion 50 is set so as to have a relatively small value, that is, elastically deform with a small load, at least in the region A where the load starts to act. As a result, when air vibration is transmitted from the hot gas bypass pipe 109, the vibrating portion 50 is deformed with a small load due to the minute vibration. As a result, it is possible to deform the vibrating portion 50 in response to the minute vibration, absorb the vibration well, and reduce the sound pressure level at the resonance frequency as described later. The spring constant of the vibrating portion 50 in the region A is 10 N / mm or more and 100 N / mm or less. Note that FIG. 3 shows an example in which the vibrating portion 50 has a spring constant larger than that of the region A in the region B on which a load larger than that of the region A acts, but the vibration unit 50 is not limited to this. It may be the same as the area A. The non-linear characteristic of the spring constant of the vibrating portion 50 can be adjusted by, for example, Young's modulus, density, plate thickness, etc. of the vibrating portion 50. Further, in FIG. 3, the load displacement characteristics of the regions A and B are drawn as linear characteristics, but both regions A and B may have non-linear characteristics.

From the above, in the acoustic damper 1A, when the refrigerant gas flows in the hot gas bypass pipe 109, the air vibration (pressure wave) due to the refrigerant gas passes through the through hole of the hot gas bypass pipe 109 to form the acoustic unit. It is taken into the passage 3. Then, the air vibration propagating through the passage 3 propagates through the cavity 5 formed inside the vibrating portion 50, and between the inlet formed at one end of the passage 3 and the end formed by attaching the end plate 52. The air vibration propagated in is resonated and the pressure fluctuation in the hot gas bypass pipe 109 is attenuated.

By attaching the vibrating portion 50 and the end plate 52 to the outer surface of the housing 2, as shown in FIG. 2, a virtual vibration absorbing structure having a spring and a damper is formed on the outside of the housing 2. Will be. As a result, when the air vibration from the hot gas bypass pipe 109 resonates in the acoustic damper 1A, the vibrating portion 50 vibrates and the end plate 52 becomes the acoustic impedance boundary, so that the acoustic boundary condition of the acoustic damper 1A Can be changed. That is, by absorbing the vibration by the vibrating portion 50 and the end plate 52, the eigenvalue of the resonance frequency of the acoustic damper 1A can be changed, and the sound pressure level at the resonance frequency can be reduced.

FIG. 4 is an explanatory diagram showing an example of an analysis result of the relationship between the resonance frequency and the sound pressure level in the acoustic damper according to the first embodiment. In FIG. 4, the solid line shows the relationship between the resonance frequency of the acoustic damper 1A and the sound pressure level, and the broken line shows the relationship between the resonance frequency and the sound pressure level of the acoustic damper having no vibrating portion 50 as a comparative example. ing. As shown in the figure, in the acoustic damper of the comparative example, the sound pressure level peaks at the point P1 which is the resonance frequency. On the other hand, in the acoustic damper 1A of the embodiment, the two points P2 and P3 have resonance frequencies due to the vibration absorbing structure by the vibrating portion 50 and the end plate 52, and at these points P2 and P3, the sound pressure level is higher than that of the point P1. Peak becomes smaller. As described above, the acoustic damper 1A can lower the acoustic level at the resonance frequency as compared with the acoustic damper of the comparative example. In other words, when attenuating vibrations in the same frequency band, the size of the acoustic damper 1A can be made smaller, that is, the length of the quarter wavelength tube formed in the housing 2 can be shortened. In the present embodiment, the size of the acoustic damper 1A (the length of the quarter wavelength tube) can be reduced to about half of that of the comparative example.

Next, a specific configuration of the vibrating portion 50 will be described with reference to FIGS. 5 and 6. FIG. 5 is an explanatory diagram showing an example of the load displacement characteristic of the vibrating portion, and FIG. 6 is an explanatory diagram showing a specific example of the vibrating portion.

In the following description, regarding the vibrating portion 50, the surface attached to the housing 2 of the acoustic damper 1A is referred to as "lower surface 55", and the surface located on the opposite side to the lower surface 55 is referred to as "upper surface 56". The vibrating portion 50 is mainly subjected to vibration, that is, a load is applied along a direction extending between the lower surface 55 and the upper surface 56. The vibrating portion 50 is an opening in which the lower surface 55 and the upper surface 56 extend in a direction orthogonal to the load acting direction. The lower surface 55 and the upper surface 56 need only have a shape such that the lower surface 55 is along the outer surface of the housing 2.

As shown in FIG. 6, the vibrating portion 50 is an elastic body having a cavity 5 formed therein and forming a bellows shape along the direction from the lower surface 55 to the upper surface 56, and has a spring constant having a predetermined non-linear characteristic. More specifically, the vibrating portion 50 has a pair of wall portions 50A and 50B that are attached to the outer surface of the housing 2 on the lower surface 55 side and face each other. In FIG. 6, in order to show the internal structure of the vibrating portion 50, the description of the other wall portion 50B facing the one wall portion 50B is omitted. The vibrating portion 50 has a cavity 5 inside surrounded by a pair of wall portions 50A and 50B. As shown in FIG. 6, the pair of wall portions 50A and 50B have a bent portion 50C in the middle, approach each other from the housing 2 toward the bent portion 50C side, and are opposite to the housing 2 from the bent portion 50C. It separates from each other as it goes in the direction. As a result, the vibrating portion 50 exhibits a bellows shape in which a pair of wall portions 50A and 50B facing each other are bent at the bent portion 50C. The vibrating portion 50 may have a pair of wall portions 50A and 50B facing each other having a plurality of bent portions 50C.

The lower surface 55 of the vibrating portion 50 is open, and the vibrating portion 50 is fixed to the housing 2 on the lower surface 55 side. Therefore, the passage 3 formed inside the housing 2 and the cavity 5 formed inside the vibrating portion 50 communicate with each other. Further, by attaching the end plate 52 to the upper surface 56, the downstream side of the propagation of air vibration is blocked. That is, the cavity 5 of the vibrating portion 50 is a part of the propagation path of the air vibration of the acoustic damper 1A, and the end plate 52 is attached to the surface of the vibrating portion 50 opposite to the side in contact with the housing 2. The downstream side of the air vibration propagation path is blocked.

The method of forming the vibrating portion 50 according to the present embodiment is not particularly limited, but in one example, it is desirable that the vibrating portion 50 is formed by so-called laminated molding in which continuous layers made of one or more kinds of materials are deposited. In this case, the vibrating portion 50 has a continuous sedimentary layer made of one or more materials.

The acoustic damper 1A has the above configuration. When the air vibration is propagated from the hot gas bypass pipe 109 to the passage 3 of the housing 2, the air vibration propagates in the passage 3 and the cavity 5 and reaches the end plate 52 that closes the downstream side of the propagation path. Therefore, a load caused by air vibration acts on the end plate 52. When a load acts on the end plate 52, the vibrating portion 50 in which the pair of wall portions 50A and 50B are formed in a bellows shape is elastically deformed with the bent portion 50C as a base point, and the vibrating portion 51 is in FIG. 6 of the housing 2. Displaces in the vertical direction (repeated elastic deformation). That is, the end plate 52 and the vibrating portion 50 both vibrate due to air vibration. In the first embodiment, the spring constant of the vibrating portion 50 can be reduced as shown in FIG. 6 by forming the vibrating portion 50 in a bellows shape having a cavity 5 inside. Since the vibrating portion 50 has a spring constant having a predetermined non-linear characteristic, it can be deformed with a small load.

As described above, the refrigerator 100 according to the first embodiment includes a compressor 101 that compresses the refrigerant, a condenser 102 that condenses the refrigerant compressed by the compressor 101, and a refrigerant condensed by the condenser 102. The gas fluid among the plurality of pipes (refrigerant pipes 106a, 106b, 106c and hot gas bypass pipe 109) connecting the compressor 101, the condenser 102 and the evaporator 103, and the plurality of pipes. A housing 2 (acoustic) including an acoustic damper 1A provided in the hot gas bypass pipe 109 as a gas fluid pipe through which the hot gas bypass pipe 109 flows, and the acoustic damper 1A forming a passage 3 for taking in air vibration generated in the hot gas bypass pipe 109. It has a damper main body) and a vibrating portion 50 that has a predetermined spring constant and is attached to the inner surface of an end plate 52 that closes the passage 3 and vibrates due to air vibration.

With this configuration, the vibration unit 50 having a predetermined spring constant can absorb the vibration of the acoustic damper 1A, and the acoustic boundary condition of the acoustic damper 1A can be changed. As a result, the intrinsic value of the resonance frequency of the acoustic damper 1A can be changed, so that the fluid sound of a desired frequency in the hot gas bypass pipe 109 of the refrigerator 100 can be satisfactorily attenuated by the acoustic damper 1A. Therefore, it is possible to suppress the resonance between the fluid sound in the hot gas bypass pipe 109 and the NZ sound generated in the compressor 101. Further, since the sound pressure level can be reduced by changing the intrinsic value of the resonance frequency of the acoustic damper 1A, it is possible to reduce the size of the acoustic damper 1A aiming at the vibration damping of the same resonance frequency. Therefore, according to the first embodiment, the noise in the refrigerator 100 can be satisfactorily attenuated by the small acoustic damper 1A with a simpler configuration.

Further, the vibrating portion 50 is attached to the housing 2 and has a bellows shape in which a cavity 5 communicating with the passage 3 is formed inside, and the end plate 52 is attached to the vibrating portion 50 to form the cavity 5 and the passage 3. Block. With this configuration, the bellows-shaped vibrating portion 50 can be vibrated by air vibration together with the end plate 52 that closes the passage 3. That is, when the air vibration resonates with the acoustic damper 1A, the vibrating portion 51 vibrates and the end plate 52 serves as the impedance boundary of the acoustic, so that the acoustic boundary condition of the acoustic damper 1A can be changed.

[Second Embodiment]
Next, the refrigerator according to the second embodiment will be described. The refrigerator according to the second embodiment has an acoustic damper 1B instead of the acoustic damper 1A of the refrigerator 100 according to the first embodiment. Since other configurations of the refrigerator according to the second embodiment are the same as those of the refrigerator 100 according to the first embodiment, illustration and description will be omitted.

FIG. 7 is an explanatory diagram schematically showing an acoustic damper included in the refrigerator according to the second embodiment, and FIG. 8 is an explanatory diagram showing a specific example of a vibrating portion of the acoustic damper shown in FIG. 9 is an explanatory diagram showing a specific example of a main part of the vibrating portion shown in FIG. The acoustic damper 1B shown in FIG. 7 is provided in the hot gas bypass pipe 109 of the refrigerator 100, similarly to the acoustic damper 1A according to the first embodiment. The acoustic damper 1B has a vibrating portion 51 instead of the vibrating portion 50 of the acoustic damper 1A of the first embodiment, and has an end plate 62 instead of the end plate 52. Further, the acoustic damper 1B has a diaphragm 58. Since the other configurations of the acoustic damper 1B are the same as those of the acoustic damper 1A, the description thereof will be omitted, and the same components will be designated by the same reference numerals.

As shown in FIG. 7, in the second embodiment, the passage 3 is closed by attaching the end plate 62 to the surface of the housing 2 opposite to the side in contact with the hot gas bypass pipe 109. Further, one end of the vibrating portion 51 is connected to the inner surface of the end plate 62, and a vibrating plate 58 having a predetermined rigidity is attached to the other end of the vibrating portion 51.

As shown in FIG. 7, the vibrating portion 51 is provided inside the housing 2 by attaching one end to the inner surface of the end plate 62. The vibrating unit 51 has a plurality of elastic members 60 regularly arranged on the diaphragm 58. As shown in FIG. 8, in one example, the plurality of elastic members 60 are regularly arranged on the diaphragm 58. Each elastic member 60 has a polygonal pyramid trapezoid, and is formed in a shape in which square pyramid trapezoids are continuously stacked as shown in FIG. 9 as an example. Specifically, it is formed by overlapping the openings on the small diameter side of two quadrangular pyramid trapezoidal elastic members so as to abut each other. Further, openings on the large diameter side are formed as an upper surface 56 and a lower surface 55, respectively, and are fixed to the housing 2 on the upper surface 56. The method of forming each elastic member 60 is not particularly limited, but for example, it is desirable that each elastic member 60 is formed by so-called laminated molding in which continuous layers made of one or more kinds of materials are deposited. In this case, each elastic member 60 has a continuous deposition layer made of one or more materials. As described above, the shape of the elastic member 60 has been described as a quadrangular pyramid trapezoid, but the elastic member 60 may have a polygonal pyramid trapezoidal shape such as a triangular pyramid trapezoid or a pentagonal pyramid trapezoid.

The diaphragm 58 is a plate-shaped member having a predetermined rigidity, and is attached to the other end of the vibrating portion 51. The diaphragm 58 is fixed to the lower surface of each elastic member 60 constituting the vibrating portion 51. Further, the diaphragm 58 is arranged at a distance from the inner surface of the housing 2, and a gap is formed between the diaphragm 58 and the housing 2. In other words, the diaphragm 58 is attached to the end plate 62 via the vibrating portion 51 (a plurality of elastic members 60), and is made vibrable in the passage 3.

The acoustic damper 1B has the above configuration. When the air vibration is propagated from the hot gas bypass pipe 109 to the passage 3 of the housing 2, the air vibration propagates in the passage 3 and reaches the end plate 62 that closes the downstream side of the propagation path. In the process, a load caused by air vibration acts on the diaphragm 58 and is transmitted to the vibrating portion 51 having a plurality of elastic members 60. As a result, when a load acts on the vibrating portion 51, the vibrating portion 51 vibrates and elastically deforms, and the vibrating portion 51 is displaced in the vertical direction in FIG. 7 of the housing 2 (elastic deformation is repeated). Along with this, the diaphragm 58 fixed to the vibrating portion 51 is also displaced in the vertical direction in FIG. 7 of the housing 2. That is, both the diaphragm 58 and the vibrating portion 51 vibrate due to air vibration. Since the vibrating portion 51 has a spring constant having a predetermined non-linear characteristic, it can be deformed with a small load.

As described above, in the second embodiment, the acoustic damper 1B is attached to the end plate 62 via the vibrating portion 51, further has a vibrating diaphragm 58 in the passage 3, and the vibrating portion 51 , Has a plurality of elastic members 60 provided between the inner surface of the end plate 62 and the diaphragm 58.

With this configuration, the vibrating portion 51 having a plurality of elastic members 60 together with the diaphragm 58 arranged in the passage 3 can be vibrated by air vibration. That is, when the air vibration resonates in the acoustic damper 1B, the vibrating portion 51 vibrates and the diaphragm 58 becomes the acoustic impedance boundary, so that the acoustic boundary condition of the acoustic damper 1B can be changed.

Further, in the second embodiment, the vibrating portion 51, that is, the plurality of elastic members 60 are arranged inside the housing 2. By providing the vibrating portion 51 inside the housing 2, it is possible to reduce the size of the acoustic damper 1B as compared with the case where the vibrating portion 51 is provided on the outer surface of the housing 2.

Further, since the vibrating portion 51 has a plurality of elastic members 60, it is possible to reduce the influence of the action direction of the load caused by the air vibration (pressure wave) on the vibration damping performance, and the stable vibration damping performance is maintained. can do.

Further, the elastic member 60 has a shape in which polygonal pyramid trapezoids are continuously stacked. With this configuration, the spring constant of the vibrating portion 51 can be easily adjusted, and the vibrating portion 51 can have a simple configuration.

In the first embodiment and the second embodiment, the gas fluid pipe provided with the acoustic dampers 1A and 1B is a hot gas bypass pipe 109 that bypasses the refrigerant from the evaporator 103 to the condenser 102. With this configuration, the fluid noise in the hot gas bypass pipe 109 between the evaporator 103 and the condenser 102 can be satisfactorily damped. However, the acoustic dampers 1A and 1B are not limited to the hot gas bypass pipe 109, but at least one of the pipe through which the gas fluid flows and the discharge pipe (refrigerant pipe 106a) of the compressor 101 among the plurality of pipes included in the refrigerator 100. It may be provided in one or one.

Further, in the first embodiment and the second embodiment, the predetermined spring constants of the vibrating portions 50 and 51 are 10 N / mm or more and 100 N / mm or less. With this configuration, the vibrating portions 50 and 51 can be deformed by the action of a relatively small load. That is, the vibration units 50 and 51 can be deformed in response to minute vibrations to absorb the vibrations. However, the predetermined spring constants of the vibrating portions 50 and 51 are not limited to this.

Further, in the first embodiment and the second embodiment, it is preferable that the vibrating portions 50 and 51 have a continuous sedimentary layer made of one or more kinds of materials. By forming the vibrating portions 50 and 51 by laminated molding, the vibrating portions 50 and 51 having a predetermined spring constant can be easily obtained.

1A, 1B Acoustic damper 2 Housing 3 Passage 5 Cavity 50, 51 Vibrating part 52, 62 End plate 58 Diaphragm 60 Elastic member 100 Refrigerator 101 Compressor 102 Condenser 103 Evaporator 106 Circulation path 106a, 106b, 106c Refrigerant piping 109 Hot gas bypass piping

Claims (7)

A compressor that compresses the refrigerant and
A condenser that condenses the refrigerant compressed by the compressor, and
An evaporator that evaporates the refrigerant condensed by the condenser, and
With a plurality of pipes connecting the compressor, the condenser and the evaporator,
Of the plurality of pipes, an acoustic damper provided in at least one of the gas fluid pipe through which the gas fluid flows and the discharge pipe of the compressor,
With
The acoustic damper is
An acoustic damper body that forms a passage that takes in air vibrations generated in the piping,
A vibrating portion that has a predetermined spring constant and is attached to the inner surface of an end plate that closes the passage and vibrates due to the air vibration.
A refrigerator characterized by having. The refrigerator according to claim 1, wherein the gas fluid pipe provided with the acoustic damper is a hot gas bypass pipe that bypasses the refrigerant from the evaporator to the condenser. The vibrating portion is attached to the acoustic damper main body and has a bellows shape in which a cavity communicating with the passage is formed inside.
The end plate is attached to the vibrating portion and closes the cavity and the passage.
The refrigerator according to claim 1 or 2, wherein the refrigerator is characterized by the above. The acoustic damper is attached to the end plate via the vibrating portion, and further has a vibrating diaphragm in the passage.
The vibrating portion has a plurality of elastic members provided between the inner surface of the end plate and the vibrating plate.
The refrigerator according to claim 1 or 2, wherein the refrigerator is characterized by the above. The refrigerator according to claim 4, wherein the elastic member has a shape in which polygonal pyramid trapezoids are continuously stacked. The refrigerator according to any one of claims 1 to 5, wherein the predetermined spring constant is 10 N / mm or more and 100 N / mm or less. The refrigerator according to any one of claims 1 to 6, wherein the vibrating portion has a continuous sedimentary layer made of one or more kinds of materials.

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