CN110552882B

CN110552882B - Rotary machine

Info

Publication number: CN110552882B
Application number: CN201810730552.6A
Authority: CN
Inventors: 约根·特罗巴霍桑马丁; 玛丽亚·比利亚努埃瓦马多; 阿纳·迈斯特拉米洛; 弗朗西斯科·哈维尔·桑斯拉尔劳里
Original assignee: Entecnia Consulting SLU
Current assignee: Entecnia Consulting SLU
Priority date: 2018-06-04
Filing date: 2018-07-05
Publication date: 2023-03-31
Anticipated expiration: 2038-07-05
Also published as: EP3578755B1; CN110552882A; EP3578755C0; ES2953294T3; EP3578755A1

Abstract

A rotary machine, comprising: a pump chamber; an electric motor; at least one inlet port for drawing outside air, in fluid communication with the at least one inlet aperture of the pump chamber; at least one outlet port in fluid communication with an exterior region of the rotary machine to discharge compressed air exiting the pump chamber via at least one outlet aperture of the pump chamber; a noise reduction element comprising at least one damping duct for reducing the sound pressure level of the compressed air; an intermediate chamber between a base of the pump chamber and the motor, the inlet port and the outlet port being connected to the intermediate chamber; and an intermediate duct at least partially housed in the intermediate chamber to communicate the inlet port with the at least one inlet aperture of the pump chamber, the intermediate duct leaving an empty space in the intermediate chamber and the noise reducing element being at least partially disposed within a portion of the empty space. The at least one outlet opening is provided in the base of the pump chamber and opens into the empty space of the intermediate chamber so that the compressed air leaving the pump chamber via the outlet opening enters the damping duct of the noise reducing element.

Description

Rotary machine

Technical Field

The present invention relates to the field of rotary machines, and in particular to the following pumps: the pump comprises a rotor in which one or more blades are inserted, the rotor being housed in a housing in which, when the rotor moves, subspaces are formed between the one or more blades, a wall of the housing and the rotor.

Background

Many applications require a pump, a vacuum pump for amplifying the effect of force, or any other type of pump. These pumps generally include a housing and a rotor housed within the housing. The rotor includes one or more slots such that a vane is at least partially introduced into each of the slots. The housing houses the rotor, but the internal volume of the housing is greater than the volume occupied by the rotor and blades. Thus, when the rotor rotates, the blades have some space to leave the rotor due to centrifugal force or any other force provided in the pump. This internal volume of the housing is designed such that one or more vanes alternately enter and exit the rotor, so that the sub-chambers formed between successive two vanes, corresponding portions of the housing wall and the rotor have a variable volume, depending on the position of the rotor. In the case of a single slot for a single vane, the slot allows the single vane to exit the rotor at two diametrically opposed locations, such that the vane divides the main chamber into different sub-chambers.

Thus, when the rotor rotates, the sub-chambers formed between successive two vanes, corresponding parts of the chamber wall and the rotor have a variable volume, depending on the position of the rotor. A fluid inlet hole in the chamber wall is fluidly connected to the means requiring a pressure reduction and supplies a compressible fluid, such as air or any other gas, to the chamber at the inlet location. Since the inlet position is fixed, but the vanes move with the rotor, the inlet position belongs to different sub-chambers when the rotor rotates. The fluid outlet opening is in turn located at an outlet position of the chamber wall and is in fluid connection with an outlet fluid area, such as the atmosphere or a conduit belonging to a different device. When the pressure at this outlet location is greater than the pressure in the outlet fluid region, the fluid exits the chamber.

The fluid pressure is different at each instant, thereby generating a pressure wave having a certain frequency and amplitude. These pressure waves generate a significant level of noise due to the high rotational speed of the machine.

In particular, noise at high frequencies of 1000Hz or more is rather unpleasant for human listeners, and the generation of such high frequency noise may lead to a loss of commercial value of any device. For example, in the automotive industry, product specifications include stringent NVH requirements.

Noise reducing means are known in the art, such as for example WO-2017/067819-A1, WO-03046384-A1, WO-14075660-A1, WO-14075658-A2, US-4747761-A.

In some existing products, elements to reduce the noise level are assembled outside the rotary machine, resulting in an increase in installation space.

Disclosure of Invention

The invention provides a solution to this problem by a noise reducing arrangement according to claim 1. Preferred embodiments of the invention are defined in the dependent claims.

A first aspect of the invention relates to a rotary machine including:

a pump chamber including a base, a cover, and a sidewall defining an interior space; and

a rotor received (at least partially received) in the interior space of the pump chamber. The rotor comprises at least one slot and at least one blade, each blade being at least partially introduced into the at least one slot of the rotor;

an electric motor having a drive shaft passing through the central opening of the base to drive the rotor;

at least one inlet port for drawing air from the means intended to reduce the pressure, the inlet port being in fluid communication with the at least one inlet aperture of the pump chamber. The inlet port may be provided in a base of the pump chamber or a lid of the pump chamber;

at least one outlet port in fluid communication with the first outer region of the rotary machine for discharging compressed air exiting the pump chamber via at least one outlet aperture therein;

a noise reducing element comprising at least one damping duct for reducing the sound pressure level of compressed air (the at least one damping duct comprising at least one inlet opening and at least one outlet opening and allowing fluid to pass but restricting free passage of sound);

an intermediate chamber between the base of the pump chamber and the motor, the inlet and outlet ports being connected to the intermediate chamber. The intermediate chamber may include an upper base, a base of the motor, and a sidewall or peripheral wall. Preferably, the upper base constitutes the base of the pump chamber, but alternatively the base of the pump chamber may be another element mounted on the upper base. The inlet port may be connected to the sidewall.

The rotary machine according to the invention comprises an intermediate duct at least partially housed in the intermediate chamber for communicating the inlet port with said at least one inlet aperture of the pump chamber. The intermediate duct leaves an empty space in the intermediate chamber, and the noise reducing element is at least partially disposed within a portion of the empty space. The at least one outlet opening is arranged in the base of the pump chamber and opens into this empty space of the intermediate chamber, so that the compressed air leaving the pump chamber via the outlet opening enters the damping duct of the noise-reducing element. When the base of the pump chamber is another element, the upper base of the intermediate chamber comprises a hole or opening corresponding to the at least one outlet hole to allow compressed air to travel into the intermediate chamber.

In some embodiments of the invention, the noise reduction element occupies only a portion of the empty space of the intermediate chamber.

In some embodiments, the damping duct includes at least one outlet opening to an empty space of the intermediate chamber such that at least a portion of the compressed air circulating within the damping duct is discharged into the empty space and into an outlet port for discharge to an external region of the rotary machine.

In some embodiments, the noise reducing element is configured (and mounted within the intermediate chamber) such that the inlet opening of the damping duct faces the outlet opening of the pump chamber to establish a direct connection between the outlet opening and the inlet opening of the damping duct. In these embodiments, the noise reducing element (or at least a portion of the noise reducing element) may be disposed in contact with the base of the pump chamber. In an alternative embodiment, the noise reducing element comprises a protrusion (e.g. a cylindrical protrusion) surrounding the inlet opening of the damping duct, such that the protrusion is directly connected with the outlet opening of the pump chamber. Thus, the compressed air enters directly into the inlet opening of the damping duct without passing through the empty space of the intermediate chamber.

In some alternative embodiments, the noise reducing element defines an inlet expansion space in the intermediate chamber, the inlet expansion space being in fluid communication with an outlet aperture in the base of the pump chamber. The damping duct comprises at least an inlet opening provided in the inlet expansion space, such that compressed air exiting from the pump chamber via the outlet opening is passed into the inlet expansion space and expands therein, and at least a part of the compressed air (preferably a major part of the compressed air) enters the damping duct via the inlet opening and then circulates within the damping duct. Preferably, the inlet expansion space is a substantially closed space defined between the noise reducing element and the inner wall of the intermediate chamber, such that the simplest way of exit of the compressed air is through the damping duct.

In some embodiments, the noise reducing element comprises at least an outlet opening to an empty space of the intermediate chamber, such that at least a portion of the compressed air circulating within the damping duct is discharged into the empty space and into an outlet port for discharge to an external region of the rotary machine. The damping duct may comprise a plurality of outlet openings.

In some embodiments, the noise reduction element defines an outlet expansion space in the intermediate chamber, the outlet expansion space being in fluid communication with the outlet port. The damping duct includes at least an outlet opening disposed in the outlet expansion space such that compressed air circulating within the damping duct is discharged into the outlet expansion space and into the outlet port for discharge to an external region of the rotary machine. Preferably, the outlet expansion space is a substantially closed space defined between the noise reducing element and the outer wall of the intermediate chamber, such that the simplest way of exit of the compressed air is through the outlet port.

In an alternative embodiment, the noise reducing element includes an outlet port such that the damping duct discharges compressed air directly to the outer region without passing through the intermediate chamber.

In some embodiments, the noise reduction elements include holes orthogonal to the damper tube, such that the compressed air is forced to sharply redirect the compressed air (within the damper tube) to improve noise reduction.

In some embodiments, the noise reduction element includes an inner expansion region having a cross-section larger than the cross-section of the damping duct such that the compressed air undergoes expansion within the damping duct to improve noise reduction.

In some embodiments, the damping conduit may be a serpentine conduit or a labyrinth conduit. The noise reduction element may include a plurality of walls defining a labyrinth duct.

In some embodiments, the damping conduit (e.g., a portion of the wall defining the labyrinth conduit) is at least partially mounted or incorporated in the base of the pump chamber or in the upper base of the intermediate chamber and housed in the intermediate chamber. The damping duct is disposed on an opposite side of the base from the pump chamber and faces (and is housed in) the intermediate chamber.

In other embodiments, the damping conduit (e.g., a portion of the wall defining the labyrinth conduit) is at least partially housed in the base of the motor.

In another embodiment, a first portion of the wall is incorporated in the base of the pump chamber or in the upper base of the intermediate chamber and a second portion of the wall is incorporated in the base of the motor for defining the labyrinth path. The first and second portions of the wall defining the labyrinth duct may also be mounted or attached to the upper base and the base of the motor, respectively.

The noise reducing elements may comprise noise damping material, such as plastic material or foam material.

The rotary machine of the present invention has several advantages and/or differences over previous devices:

-the noise reduction system is arranged in an empty and unused space. In this way, the incorporation of the noise reduction system into the rotary pump does not mean that the volume required to mount the rotary pump is increased.

The noise reduction system is housed in the intermediate chamber and can therefore be protected from the external environment. This means that the different components of the system do not have to meet specific requirements in terms of material or geometry for being arranged externally.

The noise reduction element of the invention can be designed as a separate component of the rotary pump (and without the special requirements imposed by the manufacture of the rotary machine), or can be incorporated in the base of the motor or in the intermediate chamber and therefore does not require additional components.

The device of the invention allows the design of the noise reduction system to be optimized for various pumps, vacuum ranges, motor types, and voltages or noise frequencies to be damped.

The noise reduction system allows to incorporate different damping solutions, such as air expansion, ducts with different cross-sections or lengths, labyrinth ducts or blind ducts.

Drawings

To complete the description and to provide a better understanding of the invention, a set of drawings is provided. The accompanying drawings, which form an integral part of the specification and illustrate embodiments of the invention, are not to be construed as limiting the scope of the invention, but merely as exemplifications of how the invention may be carried out.

The drawings include the following figures:

fig. 1A, 1B and 1C show perspective views of the rotary pump of the present invention.

Fig. 2A, 2B, 2C, 2D, 2E, 2F, 2G and 2H show a first embodiment of a noise reduction element according to the invention.

Fig. 3A and 3B show a second embodiment of a noise reduction element according to the invention.

Fig. 4A, 4B and 4C show a third embodiment of a noise reduction element according to the invention.

Fig. 5A and 5B show a fourth embodiment of a noise reduction element according to the invention.

Fig. 6A, 6B and 6C show a fifth embodiment of a noise reduction element according to the invention.

Fig. 7A and 7B show a sixth embodiment of a noise reduction element according to the invention.

Fig. 8A, 8B and 8C show a seventh embodiment of a noise reduction element according to the invention.

Detailed Description

Fig. 1A, 1B and 1C show a rotary machine according to the present invention, which includes a pump chamber 1 defined by a base 11, a cover 12 and a side wall 13, the pump chamber 1 accommodating a rotor 14 and the rotor 14 being accommodated in an inner space of the pump chamber 1. The rotor 14 comprises at least one slot 141 and at least one vane 142, said at least one vane 142 being at least partially introduced into the slot 141 of the rotor 14. For clarity, in fig. 1C, the side walls and cover have been partially removed.

The rotary machine further comprises an electric motor 2 and an intermediate chamber 4, the electric motor 2 having a drive shaft 3 to drive a rotor 14, the intermediate chamber 4 being located between the base of the pump chamber 1 and the motor 2. In the embodiment shown in the figures, the intermediate chamber 4 comprises an upper base defining the base 11 of the pump chamber, the base 21 of the motor, and a lateral wall 41. In an alternative embodiment (not shown), the base 11 may be a separate element (e.g. a sheet or plate) attached or mounted on the upper wall of the intermediate chamber 4.

The rotary machine comprises at least one inlet port 5 for sucking air from another device (not shown). The inlet port 5 is connected to a side wall 41 of the intermediate chamber 4 and is in fluid communication with the at least one inlet aperture 15 of the pump chamber 1 via an intermediate conduit 51, the intermediate conduit 51 being at least partially housed in the intermediate chamber 4 for communicating the inlet port 5 with the at least one inlet aperture 15 of the pump chamber 1. The inlet opening 15 may be provided in the base 11 of the pump chamber 1. In this case, the intermediate duct 51 is completely housed inside the intermediate chamber 4, as shown in fig. 1A to 1C, 2A to 2H, or 3A to 3B. The inlet opening may also be provided in the cover portion 12 of the pump chamber 1, in which case a first portion 511 of the intermediate duct 51 is received in the intermediate chamber 4, as shown in fig. 4A to 4C, 5A to 5B, 6A to 6C, 7A to 7B and 8A to 8C, and a second portion (not shown) of the intermediate duct 51 is provided outside the intermediate chamber 4 to connect with the inlet opening 15 of the pump chamber 1.

The rotary machine further comprises at least one outlet port 6 in fluid communication with an external region of the rotary machine. The outlet port 6 is connected to the intermediate chamber 4 for discharging compressed air that leaves the pump chamber 1 via at least one outlet opening 16, said at least one outlet opening 16 being located in an upper base of the intermediate chamber 4 constituting the base 11 of the pump chamber 1.

The rotary machine further comprises a noise reducing element 7, the noise reducing element 7 comprising at least one damping duct 71 for reducing the sound pressure level of the compressed air leaving the pump chamber 1. The noise reduction element 7 is arranged in an empty space 410 in the intermediate chamber 4, as can be seen for example in fig. 1B.

In some embodiments of the invention, as shown in fig. 2A, 2B, 2C, 2D, 2E, 2F, 2G and 2H, the noise reduction element 7 occupies only a portion of the empty space 410 of the intermediate chamber 4. In these embodiments, the height of the noise reducing elements 7 is approximately equal to the height of the interior space of the intermediate chamber 4 (these heights are measured in the direction of the rotor axis). In these embodiments, the intermediate duct 51 is housed entirely in the intermediate chamber 4 to connect the inlet port 5 with the inlet aperture 15 housed in the base 11 of the pump chamber 1. In the embodiments shown in these figures, the inlet aperture 15 is provided in the upper base of the intermediate chamber constituting the base 11.

Fig. 2A, 2B and 2C show an embodiment of the noise reducing element 7, the noise reducing element 7 being configured to define an inlet expansion space 411 in the intermediate chamber 4, the inlet expansion space 411 being arranged in the intermediate chamber 4 in fluid communication with the outlet opening 16 in the base 11 of the pump chamber 1. Preferably, the inlet expansion space 411 is arranged below the outlet opening 16 and faces the outlet opening 16, so that the outlet opening 16 opens directly into the inlet expansion space 411. The damping duct 71 of the noise reducing element 7 comprises at least an inlet opening 711 provided in this inlet expansion space 411, so that at least a part of the compressed air exiting from the pump chamber 1 via the outlet opening 16 passes into the inlet expansion space 411 and expands in the inlet expansion space 411 and enters the damping duct 71 via the inlet opening 711 and then circulates inside the damping duct 71. Preferably, the inlet expansion space 411 is a substantially closed space defined between the recess 72 of the noise reducing element 7 and the inner tubular projection 42 of the intermediate chamber 4, so that the simplest way of escape of the compressed air from the pump chamber is through the damping duct 71.

The noise reducing element 7 comprises a plurality of outlet openings 712 opening into the empty space 410 of the intermediate chamber 4, so that the compressed air circulating within the damping duct 71 is discharged into the empty space 410 and enters the outlet port 6 to be discharged to the external region of the rotary machine.

In some embodiments, as shown in fig. 2D, 2E, 2F, 2G and 2H, the noise reduction element 7 is configured to define an outlet expansion space 412 in the intermediate chamber 4 in fluid communication with the outlet port 6. Preferably, the outlet expansion space 412 is a substantially closed space defined between the outer wall of the noise reducing element 7 and the outer protrusion 43 of the intermediate chamber 4, the outlet expansion space 412 being arranged above the outlet port 6 and facing the outlet port 6. The damping duct 71 comprises at least an outlet opening 713 arranged in the outlet expansion space 412, so that a part of the compressed air circulating within the damping duct 71 is discharged into the outlet expansion space 412 and into the outlet port 6 to be discharged to the outer area of the rotary machine.

The damping duct also comprises a plurality of outlet openings 712 opening into the empty space 410 of the intermediate chamber 4, so that a portion of the compressed air circulating within the damping duct 71 is discharged into the empty space 410 and enters the outlet port 6 to be discharged to the external region of the rotary machine.

In some embodiments, as shown in fig. 2F and 2H, the noise reduction element 7 includes vertical holes 714 that are orthogonal to the damping tube 71, such that the compressed air is forced to sharply change the direction of the compressed air (within the noise reduction element 7) to improve noise reduction.

In some embodiments, as shown in fig. 2G, the noise reducing element 7 includes an inner expansion region 715 having a cross-section larger than the cross-section of the damping duct 71, such that the compressed air undergoes expansion within the damping duct 71 to improve noise reduction.

Fig. 3A and 3B show a further embodiment of the noise reduction element 7. In this embodiment, the noise reducing element 7 comprises a cylindrical protrusion 73, the cylindrical protrusion 73 surrounding the inlet opening 711 of the damping duct 71, such that the protrusion 73 is directly connected with the outlet opening 16 of the pump chamber 1. Thus, the height of the noise reducing elements 7 may be smaller than the height of the inner space of the intermediate chamber 4 (these heights are measured in the direction of the rotor axis). In this embodiment, the compressed air leaving the pump chamber 1 enters directly into the inlet opening 711 of the damping duct 71 without passing through the empty space 410 of the intermediate chamber 4. The damping duct 71 also comprises a plurality of outlet openings 712 opening into the empty space 410 of the intermediate chamber 4, so that the compressed air circulating inside the damping duct 71 is discharged into the empty space 410 and then enters the outlet port 6 to be discharged to the external area of the rotary machine.

In the embodiment shown in fig. 4A, 4B and 4C, the noise reducing element 7 is configured and mounted in the intermediate chamber 4 such that the inlet opening 711 of the damping duct 71 faces the outlet opening 16 of the pump chamber 1 to establish a direct connection between the outlet opening 16 and the inlet opening 711 of the damping duct 71. In this embodiment, the noise reducing element 7 (or at least a portion of the noise reducing element) may be in contact with the base of the pump chamber 1. In this embodiment, noise reduction element 7 comprises outlet port 6, so that damping duct 71 discharges compressed air directly to the outer region without passing through intermediate chamber 4.

Fig. 5A and 5B show an embodiment of a noise reduction element 7 occupying the entire empty space 410 of the intermediate chamber 4. The noise reducing element 7 is configured and mounted in the intermediate chamber 4 such that the inlet opening 711 of the damping duct 71 faces the outlet opening 16 of the pump chamber 1 to establish a direct connection between the outlet opening 16 and the inlet opening 711 of the damping duct 71. In this embodiment, the noise reducing element 7 comprises an outlet port 6, so that the damping duct 71 discharges compressed air directly to the outer region without passing through the intermediate chamber 4.

In the embodiment shown in fig. 6A, 6B and 6C, the damping duct 71 is a labyrinth duct. The noise reducing element 7 comprises a plurality of walls 74 defining a labyrinth duct. These walls 74 are mounted on the base 21 of the motor 2. Figure 6C shows the path followed by the compressed air between the starting point 741 of the labyrinth communicating with the outlet aperture 16 of the pump chamber and the end point 742 of the labyrinth communicating with the outlet port 6. In this embodiment, the noise reducing element 7 comprises an outlet port 6, so that the damping duct 71 discharges compressed air directly to the outer region without passing through the intermediate chamber 4.

The embodiment shown in fig. 7A and 7B shows a noise reduction element 7 comprising a plurality of walls 74 defining a labyrinth duct. These walls 74 are mounted or integrated in the upper wall of the intermediate chamber 4 and are housed in the intermediate chamber 4. Figure 7B shows the path followed by the compressed air between the starting point 741 of the labyrinth communicating with the outlet aperture 16 of the pump chamber and the end point 742 of the labyrinth communicating with the outlet port 6. In this embodiment, the noise reducing element 7 comprises an outlet port 6, so that the damping duct 71 discharges compressed air directly to the outer region without passing through the intermediate chamber 4.

In the embodiment shown in fig. 8A, 8B and 8C, the noise reduction element 7 comprises a plurality of walls 74 defining a labyrinth duct. In this embodiment, a first portion 743 of these walls is incorporated in the upper wall of the intermediate chamber 4 and a second portion 744 of these walls is incorporated in the base 21 of the motor 2. Figure 7B shows the path followed by the compressed air between the starting point 741 of the labyrinth communicating with the outlet opening 16 of the pump chamber and the end point 742 of the labyrinth communicating with the outlet port 6. In this embodiment, noise reduction element 7 comprises outlet port 6, so that damping duct 71 discharges compressed air directly to the outer region without passing through intermediate chamber 4.

In this document, the terms "comprise" and its derivatives (such as "comprises" and "comprising"), are not to be taken in an exclusive sense, i.e. these terms are not to be interpreted as excluding the possibility that what is described and defined may comprise other elements, steps, etc.

It is clear that the invention is not limited to the specific embodiments described herein, but also covers any variant (for example as regards the choice of materials, dimensions, components, configurations, etc.) that any person skilled in the art may consider within the general scope of the invention as defined in the claims.

Claims

1. A rotary machine, comprising:

a pump chamber (1), the pump chamber (1) comprising a base portion (11), a cover portion (12) and a side wall (13) defining an interior space;

a rotor (14), the rotor (14) being housed in the inner space of the pump chamber (1), the rotor (14) comprising at least one groove (141);

at least one blade (142), each blade (142) being at least partially introduced into a groove (141) of the rotor (14);

an electric motor (2), the motor (2) having a drive shaft (3), the drive shaft (3) passing through a central opening of the base (11) to drive the rotor (14);

at least one inlet port (5) for sucking air from a device intended to reduce the pressure, said inlet port (5) being in fluid communication with at least one inlet hole (15) of said pump chamber (1);

at least one outlet port (6), said outlet port (6) being in fluid communication with an external region of the rotary machine for discharging compressed air exiting the pump chamber (1) via at least one outlet aperture (16) of the pump chamber (1);

a noise reducing element (7), said noise reducing element (7) comprising at least one damping duct (71) for reducing the sound pressure level of the compressed air; and

an intermediate chamber (4), the intermediate chamber (4) being located between the base of the pump chamber (1) and the motor (2), the inlet port (5) and the outlet port (6) being connected to the intermediate chamber (4),

characterized in that it comprises an intermediate duct (51), said intermediate duct (51) being at least partially housed in said intermediate chamber (4) for communicating said inlet port (5) with said at least one inlet aperture (15) of said pump chamber, said intermediate duct (51) leaving an empty space (410) in said intermediate chamber (4) and said noise reducing element (7) being at least partially disposed within a portion of said empty space (410), and in that at least one said outlet aperture (16) is disposed in said base of said pump chamber (1) and opens into said empty space (410) of said intermediate chamber (4), so that the compressed air leaving said pump chamber (1) via said outlet aperture enters said damping duct (71) of said noise reducing element (7).

2. Rotating machine according to claim 1, wherein the noise reducing element (7) comprises at least an outlet opening (712) opening into the empty space (410) of the intermediate chamber (4), so that at least a portion of the compressed air circulating within the damping duct (71) is discharged into the empty space (410) and enters the outlet port (6) to be discharged to an external region of the rotating machine.

3. Rotating machine according to any of the preceding claims, wherein the noise reducing element (7) is configured such that an inlet opening (711) of the damping duct (71) faces the outlet opening (16) of the pump chamber to establish a direct connection between the outlet opening (16) and the inlet opening (711).

4. A rotary machine according to claim 3, wherein the noise reducing element (7) comprises a protrusion (73), the protrusion (73) surrounding the inlet opening (711) of the damping duct (71) such that the protrusion is directly connected with the outlet aperture (16) of the pump chamber (1).

5. A rotary machine according to claim 1 or 2, wherein the noise reducing element (7) defines an inlet expansion space (411) in the intermediate chamber (4), the inlet expansion space (411) being in fluid communication with the outlet opening (16) in the base of the pump chamber (1), and wherein the damping duct (71) comprises at least an inlet opening (711) provided in the inlet expansion space (411), so that the compressed air exiting from the pump chamber (1) via the outlet opening (16) passes into the inlet expansion space (411) and expands in the inlet expansion space (411), and at least a portion of the compressed air enters the damping duct (71) via the inlet opening (711) and circulates within the damping duct (71).

6. Rotating machine according to claim 1 or 2, wherein the noise reducing element (7) defines an outlet expansion space (412) in the intermediate chamber (4), the outlet expansion space (412) being in fluid communication with the outlet port (6), and wherein the damping duct (71) comprises at least an outlet opening (713) provided in the outlet expansion space (412), so that the compressed air circulating within the damping duct (71) is discharged into the outlet expansion space (412).

7. Rotating machine according to claim 1 or 2, wherein the noise reducing element (7) comprises a hole (714) orthogonal to the damping duct (71).

8. Rotating machine according to claim 1 or 2, wherein the noise reducing element (7) comprises an inner expansion area (715) having a cross section larger than the cross section of the damping duct (71).

9. Rotating machine according to claim 1 or 2, wherein the noise reducing element comprises the outlet port (6).

10. Rotating machine according to claim 1 or 2, wherein the damping duct (71) is at least partially housed in the base (11) of the pump chamber (1) or in the upper base of the intermediate chamber (4).

11. Rotating machine according to claim 1 or 2, wherein the damping duct (71) is at least partially housed in the base (21) of the motor (2).

12. A rotary machine according to claim 1 or 2, wherein the damping duct (71) comprises a serpentine duct or a labyrinth duct.

13. Rotating machine according to claim 12, wherein the noise reducing element (7) can comprise a plurality of walls (74) defining the labyrinth duct.

14. Rotating machine according to claim 13, wherein a first portion (743) of the wall (74) is incorporated in the base (11) of the pump chamber (1) or in an upper base of the intermediate chamber (4) and housed in the intermediate chamber (4), and a second portion (744) of the wall (74) is incorporated on a base (21) of the motor (2).

15. The rotary machine of claim 1 or 2, wherein the noise reducing element comprises a noise damping material.