Patent Description:
The present invention relates to the technical field of noise reduction of refrigeration apparatus, and specifically to a muffler for reducing noise of a vacuum pump.

Freshness of food in a refrigerator is closely related to temperature, humidity and gas environment, wherein oxygen is an important factor causing spoilage, deterioration and bacteria multiplication of the food. A preservation period of the food may be significantly prolonged by pumping oxygen in the compartment to control a nitrogen-to-oxygen ratio of the refrigerator.

Oxygen may be pumped out from a specific space via a vacuum pump, and discharged outside the refrigerator. However, when gas, as a medium for conducting a sound, conducts noise in the refrigerator to an external space of the refrigerator during the discharge, thereby causing noise interference.

<CIT> concerns an improved Helmholtz silencer and a manufacturing method thereof. The improved Helmholtz silencer comprises a Helmholtz silencer body and a thin-film acoustic material, wherein the two parts are coupled. The thin-film acoustic material includes a thin film and a mass block; and the mass block is arranged at the center of the thin film. When a noise frequency in a pipe is consistent with a working frequency of the silencer, fluid in the pipe does not vibrate any more based on unicellular vibration, thereby eliminating the frequency noises.

<CIT> relates to a gas suction pump assembly and a cold storage and freezing device. The gas suction pump assembly comprises a sealing box and a gas suction pump; the sealing box comprises a box body with an upper side opening, and an upper cover used for sealing and covering the upper side opening; the upper edge of the side wall of the box body and the lower edge of the side wall of the upper cover are each provided with two semicircular notches; when the upper cover is installed on the box body, the two semicircular notches of the box body are opposite to the two semicircular notches of the upper cover one to one so as to form two pipeline lead-out holes; the gas suction pump is arranged in the sealing box; and a gas inlet pipe and a gas outlet pipe of the gas suction pump are each led out of the sealing box through the corresponding pipeline lead-out hole.

<CIT>relates to a noise-airflow separate type silencer.

An object of the present invention is to provide a muffler to solve the problem of noise output of a vacuum pump.

To achieve the object, the present invention provides a muffler according to claim <NUM>. The dependent claims set out particular embodiments of the invention.

To achieve the object, the present invention provides a refrigerator vacuum assembly comprising a sealed box the sealed box comprises an upper sealing body and a lower sealing body, and the upper sealing body and the lower sealing body can be snap-fitted to define a receiving cavity; a vacuum pump is arranged in the receiving cavity, and the vacuum pump is connected with any one of the above mufflers.

A further improvement as an embodiment of the present invention, further comprises an air outlet pipe passing through the sealed box, the air inlet of the muffler is connected with the vacuum pump, and the air outlet is connected with the air outlet pipe.

A further improvement as an embodiment of the present invention, a notch portion is provided where the upper sealing body engages the lower sealing body, the vacuum assembly further comprises a seal capable of being embedded in the notch portion, the seal comprises a snap-fittable portion which is composed of two H-shaped members that are flexibly connected, the two H-shaped members can be snap-fitted to each other to form a mounted state, and the H-shaped member has a first arm and a second arm which are parallel to each other, and a connecting portion connecting the first arm with the second arm, the connecting portion has an arc-shaped surface, and arc-shaped surfaces of the two H-shaped members jointly enclose to form a hollow cavity when the H-shaped members are in the mounted state.

A further improvement as an embodiment of the present invention, the two H-shaped members, in the mounted state, match the notch portion in shape.

To achieve the object, the present invention provides a refrigerator, comprising a sealed box receiving a vacuum pump, wherein the refrigerator further comprises the muffler according to claim <NUM>, and the muffler is disposed in the sealed box and connected with the vacuum pump.

As compared with the prior art, a refrigerator vacuum assembly provided by the present invention is provided with a muffler in a closed box body receiving the vacuum pump, the shape of the hollow cavity changes so that the sound waves are enabled to be reflected and refracted irregularly and the energy is dissipated, and vibrational noise of the vacuum pump is prevented from being conducted through the sealed box.

The present invention will be described in detail in conjunction with specific embodiments shown in the figures. However, these embodiments are not limited to the present invention. Variations in terms of structure, method or function made by those having ordinary skill in the art according to these embodiments are all comprised in the scope of the present invention.

Terms indicating positions and directions described in the present invention all take a vacuum pump as a reference. An end close to the vacuum pump is a proximal end, and an end away from the vacuum pump is a distal end.

Referring to <FIG>, in an embodiment of the present invention, a vacuum pump <NUM> is received in a sealed box <NUM>, and communicated with ambient air through an air inlet pipe <NUM> and an air outlet pipe <NUM>. A proximal end of the air inlet pipe <NUM> is communicated with an air intake line of the vacuum pump <NUM>, and a distal end is communicated with a fresh-keeping space in the refrigerator compartment (not shown); a proximal end of the air outlet pipe <NUM> is communicated with an air exhaust line of the vacuum pump <NUM>, and a distal end extends towards outside the sealed box <NUM>. The sealed box <NUM> blocks air communication between the vacuum pump <NUM> and an installation environment, and achieves an effect of sound insulation. The fresh-keeping space may be either an independent compartment or a closed or semi-closed space located in a portion of the refrigerator compartment.

The sealed box <NUM> comprises an upper sealing body <NUM> and a lower sealing body <NUM>. The upper sealing body <NUM> comprises a top wall and side walls which are integrally formed and jointly define a receiving cavity with a lower end opening. The lower sealing body <NUM> comprises a bottom wall and side walls which are integrally formed and jointly define a receiving cavity with an upper end opening. The opening of the upper sealing body <NUM> and the opening of the lower sealing body <NUM> match each other, and snap fit each other to form a receiving space of the vacuum pump <NUM>.

Preferably, the upper sealing body <NUM> and the lower sealing body <NUM> are made of plastic.

Referring to <FIG>, a seal is provided between the upper sealing body <NUM> and the lower sealing body <NUM>. A first groove is formed at a lower edge of the side walls of the upper sealing body <NUM>, a second groove is formed at an upper edge of the side walls of the lower sealing body <NUM>, and the first groove matches with the second groove to form a mounting groove for a gasket ring <NUM>. In this way, the airtightness can be ensured after the upper sealing body <NUM> and the lower sealing body <NUM> are snap fitted, and sound can be prevented from being transmitted outside through a splicing gap of the sealed box <NUM>. The gasket ring <NUM> is ring-shaped and has a circular cross-section. The gasket ring <NUM> is made of an elastic material, and has a mounting tension amount <NUM>-<NUM>% when embedded in the mounting groove. When the upper sealing body <NUM> and the lower sealing body <NUM> are snap-fitted, a pressure is applied to the gasket ring <NUM> to form a <NUM>-<NUM>% compression amount, thereby ensuring the sealing effect.

<FIG> and <FIG> show that a notch portion <NUM> is provided at where the upper sealing body <NUM> and the lower sealing body <NUM> are engaged, and allows a wire connected to the vacuum pump <NUM> to pass through. In order to ensure the sealing performance of the sealed box <NUM>, a snap-fittable sealing ring <NUM> is provided at the notch portion <NUM>. The sealing ring <NUM> is made of an elastic material and integrally formed with the gasket ring <NUM>.

Referring to <FIG> and <FIG>, the sealing ring <NUM> is composed of two H-shaped members that are flexibly connected, and the H-shaped members can be snap-fitted to each other to form a mounted state that cooperates with the notch portion <NUM>. The H-shaped member has a first arm <NUM> and a second arm <NUM> parallel to each other, and a connecting portion <NUM> connecting the first arm <NUM> with the second arm <NUM>. The first arm <NUM> and the second arm <NUM> can cooperate to clamp the side wall of the box body at the edge of the notch portion <NUM> therebetween to prevent the sealing ring <NUM> from falling off from the notch portion <NUM>. The connecting portion <NUM> passes through the notch portion and connects the first arm <NUM> with the second arm <NUM>. The connecting portion <NUM> has a recessed arc-shaped surface. When the H-shaped members are snap-fitted to each other, their arc-shaped surfaces together enclose to form a hollow cavity to allow the wire to pass therethrough.

In a case where a plurality of wires passes through the notch portion <NUM>, if the wires as a whole pass through the notch portion <NUM>, since the cross section of the wires is circular, a gap formed between the wires will reduce the sealing performance. In this case, the arc-shaped surface of the connecting portion <NUM> may be wavy (not shown) to form a plurality of independent hollow cavities in the mounted state to better seal the wires with a circular cross-section.

Referring to <FIG>, a plurality of metal plates <NUM> are disposed in the sealed box <NUM>, and the metal plates <NUM> are disposed between the vacuum pump <NUM> and the side walls of the sealed box <NUM>. Since the metal plates <NUM> have a high density, they can block transmission of sound therethrough and achieve an effect of sound insulation and noise reduction.

Preferably, the metal plate <NUM> is an aluminum plate, a steel plate, or a galvanized plate.

Referring to <FIG> and <FIG>, in an embodiment of the present invention, there are two metal plates <NUM> which are respectively attached to two opposite walls of the sealed box <NUM>. The lower sealing body <NUM> and the upper sealing body <NUM> are respectively provided with a limiting structure to secure the metal plates 260a and 260b.

<FIG> shows that the bottom wall of the lower sealing body <NUM> is provided with a first rib <NUM> being parallel to a side wall <NUM> and spaced apart a distance d, and a second rib <NUM> being parallel to a side wall <NUM> and spaced apart a distance D, wherein the side wall <NUM> and the side wall <NUM> are opposed, d is the thickness of the metal plate 260a, and D is the thickness of the metal plate 260b. The spacing between the first rib <NUM> and the side wall <NUM> forms a limiting groove that limits the horizontal displacement of the metal plate 260a, and the spacing between the second rib <NUM> and the side wall <NUM> forms a limiting groove that limits the horizontal displacement of the metal plate 260b.

Referring to <FIG> and <FIG>, the lower sealing body <NUM> is further provided with a plurality of guide grooves <NUM>. The guide grooves <NUM> extend in a vertical direction and the extension direction is consistent with the insertion direction installing the metal plates <NUM>. The guide grooves <NUM> guide the metal plates <NUM> to be mounted to preset positions.

<FIG> shows that the upper sealing body <NUM> is provided with a plurality of resisting members <NUM>. When the upper sealing body <NUM> and the lower sealing body <NUM> are snap-fitted, the resisting member <NUM> againsts the top of the metal plate <NUM>. A stepped portion <NUM> is provided at an end of the resisting member <NUM> which is in contact with the metal plate <NUM>. The stepped portion <NUM> cooperates with the side walls of the upper sealing body <NUM> to form an inverted U-shaped space to accommodate the top of the metal plate <NUM>. The top surface of the stepped portion <NUM> againsts the top surface of the metal plate <NUM> and limits the displacement of the metal plate <NUM> in the vertical direction. The sides of the stepped portion abut against the sides of the metal plate <NUM> and limit the displacement of the metal plate <NUM> in the horizontal direction.

The metal plate <NUM> is disposed close to the side wall of the sealed box <NUM>. The vibration of the vacuum pump <NUM> might cause resonance of the metal plate <NUM> to form new noise which is conducted externally through the walls of the sealed box <NUM>. The above limiting structures strictly limit the position of the metal plates <NUM> to avoid resonating and generating noise.

In an embodiment of the present invention, a notch portion <NUM> is disposed on one of the upper sealing body <NUM> and lower sealing body <NUM>, or on an engagement portion of the upper sealing body <NUM> and lower sealing body <NUM>, to allow an air pipe assembly to pass therethrough.

<FIG> and <FIG> exemplarily show a case where the notch portion <NUM> is provided on the lower sealing body <NUM>. The notch portion <NUM> is provided on a side wall of the lower sealing body <NUM> close to the upper edge, and a groove is provided at peripheral edge of the notch portion <NUM> to receive a sealing unit <NUM> to ensure the airtightness of the sealed box <NUM>. The sealing unit <NUM> has an annular structure made of an elastic material.

The air pipe assembly comprises an air inlet pipe <NUM>, an air outlet pipe <NUM> and a base plate that are integrally formed. The air inlet pipe <NUM> and the air outlet pipe <NUM> are disposed through the base plate, and an outer edge of the base plate matches the shape of the notch portion <NUM>. A groove is provided on the outer edge of the base plate to mate with a flange on the periphery of the notch portion <NUM>, the mating of the groove and the flange can clamp and secure the base plate to the notch portion, and the sealing unit <NUM> is embedded at a gap between the groove and the flange.

The space of the cavity for receiving the vacuum pump <NUM> is compact and does not facilitate the operation of connecting and passing the air pipe line. It is possible to, by setting the air pipe assembly as an embedded mounting structure, conveniently embed and secure the air pipe assembly in the notch portion <NUM> after the air pipe assembly is connected with the vacuum pump <NUM>, and then snap-fit the upper sealing body <NUM> and the lower sealing body <NUM> to complete the assembling.

The gas from the air outlet pipe <NUM> is exhausted to the outside of the refrigerator after being silenced. Referring to <FIG> and <FIG>, in an embodiment of the present invention, the vacuum pump <NUM> is connected to the muffler <NUM> through the air outlet pipe <NUM>. The muffler <NUM> comprises a housing. The housing is enclosed jointly by a first bottom surface <NUM> at a proximal end, a second bottom surface <NUM> at a distal end and a side wall <NUM> connecting the first bottom surface <NUM> with the second bottom surface <NUM> to form a cylindrical hollow cavity. The muffler <NUM> is provided at the proximal end with an air inlet <NUM> connected to the air outlet pipe <NUM>, and provided with an air outlet <NUM> at the distal end. The interior of the cavity is divided into several chambers in an axial direction, the axial direction is the direction from the air inlet <NUM> to the air outlet <NUM>, and at least part of the chambers have different volumes to correspondingly remove sounds at different frequency bands. Exemplarily, the volumes of respective chambers gradually decrease in the axial direction.

Preferably, there are three chambers, which are a first chamber <NUM>, an intermediate chamber <NUM> and a second chamber <NUM> in turn from the proximal end to the distal end. The first chamber <NUM> is adjacent to the first bottom surface <NUM>, the second chamber <NUM> is adjacent to the second bottom surface <NUM>, and the intermediate cavity <NUM> is located between the first chamber <NUM> and the second chamber <NUM>. A first duct <NUM> is communicated with the air inlet <NUM> and the intermediate chamber <NUM>, a second duct <NUM> is communicated with the intermediate chamber <NUM> and the second chamber <NUM>, a third duct <NUM> is communicated with the first chamber <NUM> and the second chamber <NUM>, and a fourth duct <NUM> is communicated with the first chamber <NUM> and the air outlet <NUM>.

There may be a plurality of intermediate chambers <NUM>.

Sound waves from the vacuum pump <NUM> pass through the first duct <NUM>, the second duct <NUM>, the third duct <NUM> and the fourth duct <NUM> in turn along with the airflow, and are reflected and refracted in turn in the intermediate chamber <NUM>, the second chamber <NUM> and the first chamber <NUM> which have different volumes, and their energy is gradually dissipated. The muffling frequencies corresponding to the first chamber <NUM>, the intermediate chamber <NUM> and the second chamber <NUM> are a low frequency, a medium frequency and a high frequency. In addition, the first duct <NUM>, the second duct <NUM>, the third duct <NUM> and the fourth duct <NUM> are provided with narrow inner diameters, so that partial energy of the sound waves is converted into thermal energy and dissipated when the sound waves pass through the ducts.

The muffler is arranged in a way that the sound waves travel in a path as long as possible in the muffler to reduce the energy and are reflected and refracted in different chambers, and a better muffling effect is achieved with a smaller muffler axial distance.

Referring to <FIG>, in a further embodiment of the present invention, the muffler <NUM> comprises a housing. The housing is enclosed jointly by a first bottom surface <NUM> at a proximal end, a second bottom surface <NUM> at a distal end, and a side wall <NUM> connecting the first bottom surface <NUM> with the second bottom surface <NUM> to form a cylindrical hollow cavity. A single chamber is formed in the cavity. The muffler <NUM> is provided with an air inlet <NUM> connected to the air outlet pipe <NUM> at the proximal end, and an air outlet <NUM> provided at the distal end. A first duct <NUM> is communicated with the air inlet <NUM> and the chamber, and a distal end of the first duct <NUM> is adjacent to the second bottom surface <NUM>. A second duct <NUM> is communicated with the chamber and the air outlet <NUM>, and a proximal end of the second duct <NUM> is adjacent to the first bottom surface <NUM>.

The sound waves are reflected and refracted in the chamber, and the energy is gradually dissipated. The length of the first duct <NUM> and the second duct <NUM> is a quarter of a wavelength of a target audio to specifically eliminate the sound of the target audio. Preferably, a frequency of the target audio is <NUM>.

The first duct <NUM> and the second duct <NUM> are provided with narrow inner diameters, so that partial energy of the sound waves is converted into thermal energy and dissipated when the sound waves pass through the ducts.

In the noise generated by the vacuum pump <NUM> and conducted via gas, the high-frequency noise cannot be heard by human ears, and the noise causing interference to the user is mainly low-frequency noise. The present embodiment may purposefully eliminate low-frequency noise and make the structure of the muffler simpler.

Referring to <FIG> and <FIG>, in a further embodiment of the present invention, the muffler <NUM> is disposed inside the sealed box <NUM>, and connects the exhaust line of the vacuum pump <NUM> and the air outlet pipe <NUM>. The muffler <NUM> comprises a housing, and the housing is enclosed to form a hollow cavity for refraction and reflection of sound waves. The hollow cavity comprises a cylindrical chamber <NUM> and a rectangular parallelepiped chamber <NUM>. One of bottom surfaces of the cylindrical chamber <NUM> is connected to one surface <NUM> of the rectangular parallelepiped chamber <NUM>. The cylindrical chamber <NUM> is communicated with the interior of the rectangular parallelepiped chamber <NUM>.

The diameter of the bottom surface of the cylindrical chamber <NUM> is less than or equal to a length of a side of a connecting surface <NUM> of the rectangular parallelepiped chamber <NUM>.

The cylinder chamber <NUM> of the muffler <NUM> is provided with an air inlet <NUM> and an air outlet <NUM>, and the air inlet <NUM> and the air outlet <NUM> are arranged at an angle so that the gas entering the hollow cavity reaches the outlet through reflected and refracted. During the process, the energy loses to achieve the muffling purpose.

The air inlet <NUM> is disposed on the bottom surface <NUM> of the cylindrical chamber <NUM>, and the air outlet <NUM> is disposed on a side of the cylindrical chamber <NUM>.

The inner diameters of the air inlet <NUM> and the air outlet <NUM> are the same, so that the pressures at the two ports are balanced.

In the present embodiment, through the change of the shape of the hollow cavity, the sound waves are enabled to be reflected and refracted irregularly, and the energy is dissipated.

Referring to <FIG> and <FIG>, in a further embodiment of the present invention, a muffler <NUM> comprises a housing, and the housing is enclosed to form a hollow cavity. The muffler <NUM> is provided with an air inlet <NUM> at a proximal end and an air outlet <NUM> at a distal end. The air inlet <NUM> and the air outlet <NUM> are communicated by a duct <NUM> provided in the housing. The duct <NUM> and the housing form a sleeve structure. The duct <NUM> is filled with a medium to absorb the vibrational energy of the sound waves and weaken the sound intensity. Furthermore, the medium is silencer cotton.

A plurality of through holes <NUM> are defined on the side wall of the duct <NUM>, so that the duct <NUM> can implement communication with the cavity. The through holes <NUM> are distributed spaced apart in a circumferential direction of the sidewall of the duct <NUM>, that is, the duct <NUM> defines through holes in a plurality of directions.

Preferably, the housing is enclosed jointly by a first bottom surface <NUM> at a proximal end, a second bottom surface <NUM> at a distal end, and a side wall <NUM> connecting the first bottom surface <NUM> with the second bottom surface <NUM> to form a cylindrical hollow cavity. The first bottom surface <NUM> is provided with an air inlet <NUM>, and the second bottom surface <NUM> is provided with an air outlet <NUM>.

Preferably, a diameter of the through holes is less than <NUM>.

Preferably, the cavity enclosed by the housing is divided into several chambers arranged from the proximal end to the distal end.

The sound waves from the vacuum pump <NUM> enter the duct <NUM> from the air inlet <NUM>, and reach the air outlet <NUM> after being silenced by the medium. The sound waves at a specific frequency are attenuated and the sound intensity is weakened. During this process, partial sound waves, being diffracted by the through holes <NUM>, enter the cavity, and are further attenuated after being refracted and reflected in the cavity.

The muffler is arranged in a way that the sound intensity is reduced through multiple channels by combining medium sound reduction with cavity sound reduction and be employing small holes to implement sound wave diffraction.

It should be understood that although the description is described according to the embodiments, not every embodiment only comprises one independent technical solution, that such a description manner is only for the sake of clarity, that those skilled in the art should take the description as an integral part, and that the technical solutions in the embodiments may be suitably combined to form other embodiments understandable by those skilled in the art.

Claim 1:
A muffler (<NUM>), comprising a housing enclosed to form a hollow cavity, the cavity comprises a cylindrical chamber (<NUM>) and a rectangular parallelepiped chamber (<NUM>), the cylindrical chamber comprising two opposing bottom surfaces and a side surface joining the two bottom surfaces, wherein one of the bottom surfaces of the cylindrical chamber (<NUM>) is connected with a first surface (<NUM>) of the rectangular parallelepiped chamber (<NUM>), the cylindrical chamber (<NUM>) communicates with an interior of the rectangular parallelepiped chamber(<NUM>), and the cylindrical chamber (<NUM>) is provided with an air inlet (<NUM>) and an air outlet (<NUM>);
the air inlet (<NUM>) and the air outlet (<NUM>) are arranged at an angle; wherein
the air inlet (<NUM>) is provided on the other bottom surface (<NUM>) of the cylindrical chamber (<NUM>), characterized in that
the air outlet (<NUM>) is provided on the side surface of the cylindrical chamber (<NUM>).