ES2953294T3 - Rotative machine - Google Patents

Abstract

The rotating machine comprises a pump chamber (1), an electric motor (2), at least one inlet port (5) for drawing in external air, the inlet port being in fluid communication with at least one inlet port (15). ) of the pump chamber (1), at least one outlet port (6) in fluid communication with an external area of the rotating machine to discharge compressed air leaving the pump chamber (1) through at least one outlet hole (16) of the pump chamber (1), a noise reduction element (7) comprising at least one damping duct (71) intended to reduce the sound pressure level of the compressed air, an intermediate chamber ( 4) between the base of the pump chamber (1) and the motor (2), the inlet port (5) and the outlet port (6) being connected to this intermediate chamber (4). It also comprises an intermediate duct (51) housed at least partially in the intermediate chamber (4) to communicate the inlet port (5) with at least one inlet hole (15) of the pump chamber, the intermediate duct (4) exiting ) a free space (410) being placed at least partially within a part of this free space (410) in the intermediate chamber (4) and the noise reduction element (7). The at least one outlet hole (16) opens into this free space (410) of the intermediate chamber (4) so that the compressed air leaving the pump chamber (1) through the outlet hole enters the noise damping duct (71). reducing element (7). (Automatic translation with Google Translate, without legal value)

Description

DESCRIPTION

Rotative machine

Technical field

This invention belongs to the field of rotating machines and especially to pumps comprising a rotor with one or more vanes inserted therein, the rotor being contained in a casing where subspaces are created between the vane or vanes and the walls of the casing and the rotor when the rotor moves.

State of the art

Many applications need pumps, whether it is a vacuum pump to increase the effect of a force or any other type of pump. These pumps typically comprise a casing and a rotor housed within the casing. This rotor comprises one or more slots, such that a vane is inserted at least partially into each of said slots. The casing houses this rotor, but the interior volume of the casing is greater than the volume occupied by the rotor and vanes. Therefore, when the rotor rotates, the vanes have some space to come out of the rotor due to centrifugal force or any other force provided in the pump. This interior volume of the casing is designed so that the vanes enter and exit the rotor alternately, in such a way that the subchambers that are created between two consecutive vanes and the corresponding portion of the casing wall and the rotor have a variable volume, depending on the position of the rotor. In the case of a single vane with a single slot, the slot allows the single vane to exit the rotor at two diametrically opposite locations, so that the vane divides the main chamber into different sub-chambers.

Therefore, when the rotor rotates, the subchambers that are created between two consecutive vanes and the corresponding portion of the chamber wall and the rotor have a variable volume, depending on the position of the rotor. A fluid inlet port located in the chamber wall is in fluid connection with a device where pressure reduction is desired and feeds the chamber at an inlet point with a compressible fluid, such as air or any other gas. Since this entry point is fixed, but the vanes move with the rotor, this entry point belongs to different subchambers while the rotor rotates. A fluid outlet orifice is in turn located at an outlet point of the chamber wall and is in fluid connection with an outlet fluid zone, such as the atmosphere or a conduit belonging to a different device. When the pressure at this exit point is greater than the pressure in the exit fluid zone, the fluid leaves the chamber.

This fluid pressure is different at each instant of time, generating pressure waves with a certain frequency and amplitude. As the machine rotation speed is high, these pressure waves cause a significant level of noise.

Particularly, high frequency noise of 1000 Hz or more is considerably unpleasant to human listeners, and the generation of such high frequency noise can cause depreciation of the commercial value of any equipment. As an example, in the automotive industry, product specifications include strict NVH requirements.

Noise reduction devices are known in the art, such as WO-2017/067819-A1, WO-03046384-A1, WO-14075660-A1, WO-14075658-A2, US-4,747,761- TO.

In some existing products, noise mitigation elements are assembled outside the rotating machine, resulting in increased installation space.

Description of the invention

The invention provides a solution to this problem by means of a noise reduction device 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 comprising

a pump chamber comprising a base, a cover and a side wall defining an interior space (the cover and the side wall may be a single element, for example a lid-shaped element);

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

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

at least one inlet port for drawing air from a device where the pressure is intended to be reduced, the inlet port being in fluid communication with at least one inlet orifice of the pump chamber. The inlet hole can be placed on the base of the pump chamber or the cover of the pump chamber; at least one outlet port in fluid communication with a first exterior area of the rotating machine to discharge compressed air exiting the pump chamber through at least one outlet orifice in the pump chamber;

a noise reduction element comprising at least one damping duct intended to reduce the sound pressure level of the compressed air (the at least one damping duct comprises at least one inlet opening and at least one outlet opening and allows the passage of fluid but restricting the free passage of sound);

an intermediate chamber between the base of the pump chamber and the motor, the inlet port and the outlet port being connected to this intermediate chamber (the intermediate chamber may comprise an upper base, a lower base and a side or perimeter wall. Preferably, the upper base of this intermediate chamber constitutes the base of the pump chamber but, alternatively, the base of the pump chamber may be an additional element mounted on the upper base of the intermediate chamber. Also, in some embodiments the intermediate chamber does not comprise an upper base and the base of the pump chamber constitutes the upper base and closes the intermediate chamber. In other embodiments the lower base of the intermediate chamber may be a motor base (or a base attached to the motor) of so that the intermediate chamber only comprises an upper base and a side wall but when coupled with the base of the motor it delimits a closed interior space. The inlet port can be connected to the side wall of the intermediate chamber).

According to the invention, the rotating machine comprises an intermediate duct housed at least partially in the intermediate chamber to communicate the inlet port with the at least one inlet hole of the pump chamber. The intermediate duct leaves a free space inside the intermediate chamber and the noise reduction element is placed at least partially within a part of this free space. The at least one outlet opening of the pump chamber opens into this free space of the intermediate chamber, so that the compressed air leaving the pump chamber through the outlet opening enters the damping line of the damping element. noise reduction. The outlet hole can preferably be placed on the base of the pump chamber (when the base of the pump chamber is the upper base of the middle chamber, the outlet hole is placed on the upper base. When the base of the chamber The pump is an additional element, the outlet orifice is placed in the additional element and the upper base of the intermediate chamber comprises holes or openings in correspondence with the at least one outlet orifice to allow the passage of compressed air towards the intermediate chamber. ).

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

In some embodiments, the damping duct comprises at least one outlet opening that opens into the free space of the intermediate chamber so that at least a portion of the compressed air circulating within the damping duct is discharged into the free space and enters at the exit port to exit to an area outside the rotating machine.

In some embodiments, the noise reduction element is configured (and mounted within the intermediate chamber) so that an inlet opening of the damping duct faces the outlet port of the pump chamber, providing a connection between the port outlet and the inlet hole of the damping duct. In these embodiments, the noise reduction element (or at least a portion of the noise reduction element) may be placed in contact with the base of the pump chamber or the upper base of the intermediate chamber. In an alternative embodiment, the noise reduction element comprises a protrusion (e.g., a cylindrical protrusion) surrounding the inlet opening of the damping duct, such that the protrusion connects directly to the outlet port of the noise chamber. bomb. Thus, the compressed air enters directly into the inlet opening of the damping duct without passing through the free space of the intermediate chamber.

In some alternative embodiments, the noise reduction element defines a first inlet expansion space in the intermediate chamber in fluid communication with the outlet port (at the base of the pump chamber or at the upper base of the intermediate chamber). . The damping duct comprises at least one inlet opening positioned in this inlet expansion space so that the compressed air leaving the pump chamber, through the outlet hole, flows and expands in the expansion space. inlet and at least a part of this air (preferably the majority) enters the damping duct through the inlet opening and then circulates within the damping duct. Preferably, the inlet expansion space is a substantially closed space defined between the noise reduction element and the interior walls of the intermediate chamber, so that the easiest exit path for the compressed air is through the damping duct. .

In some embodiments, the noise reduction element comprises at least one outlet opening opening into the free space of the intermediate chamber so that at least a portion of the compressed air circulating within the damping duct is discharged into the free space. and enters the outlet port to exit to an area outside the rotating machine. The damping duct may comprise several outlet openings.

In some embodiments, the noise reduction element defines an output expansion space in the chamber intermediates in fluid communication with the exit port. The damping duct comprises at least one outlet opening located in the outlet expansion space so that the compressed air circulating inside the damping duct is discharged into the outlet expansion space and enters the outlet port. to exit to an area outside the rotating machine. Preferably, the outlet expansion space is a substantially closed space defined between the noise reduction element and the interior walls of the intermediate chamber, so that the easiest exit path for the compressed air is through the outlet port. .

In alternative embodiments, the noise reduction element comprises the outlet port so that the damping duct discharges the compressed air directly to the outer zone without passing through the intermediate chamber.

In some embodiments, the noise reduction element comprises a hole orthogonal to the damping duct such that the compressed air is forced to abruptly change its direction (within the damping duct) to improve noise reduction.

In some embodiments, the noise reduction element comprises an internal expansion area with a cross section larger than the cross section of the damping duct such that compressed air undergoes expansion within the damping duct to improve noise reduction.

In some embodiments, the buffer conduit may be a meandering or labyrinthine conduit. The noise reduction element may comprise several walls that define the labyrinth duct.

In some embodiments the damping conduit (e.g. part of the walls defining a labyrinth conduit) is mounted or integrated at least partially into the base of the pump chamber or upper base of the intermediate chamber and housed in the intermediate chamber. The damping duct is placed on a side of this base opposite the pump chamber and faces into (and is housed in) the intermediate chamber.

In other embodiments, the damping passage (e.g. part of the walls defining a labyrinth passage) is mounted or at least partially integrated into the base of the motor. The damper duct is placed on a side of this engine base that is opposite the engine and faces (is housed in) the intermediate chamber.

In another embodiment, a first part of the walls is integrated into the base of the pump chamber or upper base of the intermediate chamber and a second part of the walls is integrated into the base of the motor, to define a labyrinthine path. The first part and the second part of the walls defining the labyrinth duct can also be mounted or attached to the upper base and the motor base, respectively.

The noise reduction element may comprise a noise damping material, for example, a plastic material or a foam material.

The rotary machine of the invention comprises several advantages and/or differences compared to previous devices:

- The noise reduction system is placed in a free and unused space. In this way, the incorporation of the noise reduction system to the rotary pump does not imply an increase in the volume necessary for the assembly of the rotary pump.

- The noise reduction system is housed within the intermediate chamber and, therefore, protected from the external environment. This means that it is not necessary for the different parts of the system to meet special requirements in materials or geometry to be placed outdoors.

- The noise reduction of the invention can be designed to be an independent part of the rotary pump (and designed without special requirements derived from the manufacture of the rotary machine) or it can be integrated into the base of the motor or in the intermediate chamber and therefore Therefore, no additional parts are required.

- The device of the invention allows the design of the noise reduction system to be optimized for all types of pump, vacuum range, type of motor and electrical voltage or noise frequencies to be damped.

- The noise reduction system allows the incorporation of different damping solutions such as air expansion, ducts of different section or length, labyrinthine ducts or blind ducts.

Brief description of the drawings

To complete the description and in order to provide a better understanding of the invention, a set of drawings is provided. Said drawings form an integral part of the description and illustrate an embodiment of the invention, which should not be construed as a restriction of the scope of the invention, but only as an example of how the invention can be carried out.

The drawings include the following figures:

Figures 1A, 1B and 1C show perspective views of a rotary pump of the invention.

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

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

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

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

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

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

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

Detailed description of the invention

Figures 1A, 1B and 1C show a rotary machine according to the invention comprising a pump chamber 1 defined by a base 11 and a cover comprising a cover 12 and a side wall 13, the pump chamber 1 housing a rotor 14. This rotor 14 comprises at least one slot 141 and at least one vane 142 that is at least partially inserted into the slot 141 of the rotor 14. In Figure 1C, the side wall and cover have been partially removed for clarity.

The rotary machine also comprises an electric motor 2, which has a drive shaft 3 for driving the rotor 14, and an intermediate chamber 4 between the base 11 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 1 and a side wall 41, the intermediate chamber 4 being closed by a base 21 of the motor 5. In alternative embodiments (not shown), the base 11 of the pump chamber 1 may be a separate element (for example, a sheet or plate) attached or mounted on the upper wall of the intermediate chamber 4. The base 11 may also constitute the upper base of the intermediate chamber.

The rotating machine comprises at least one inlet port 5 for drawing air from another device (not shown). The inlet port 5 is connected to the side wall 41 of the intermediate chamber 4 and is in fluid communication with at least one inlet port 15 of the pump chamber 1, through an intermediate conduit 51 housed at least partially in the intermediate chamber 4. The inlet hole 15 can be placed in the base 11 of the pump chamber 1. In this case, the intermediate conduit 51 is completely housed within the intermediate chamber 4 as shown in figures 1, 2 or 3. The inlet hole can also be placed in the cover 12 of the pump chamber 1 in which case a first part 511 of the intermediate duct 51 is housed in the intermediate chamber 4 as shown in Figures 4, 5, 6, 7 and 8 and a second part (not shown) exists outside the intermediate chamber 4 to connect with the inlet hole 15 of the pump chamber 1.

The rotating machine also comprises at least one outlet port 6 in fluid communication with an external area of the rotating machine. This outlet port 6 is connected to this intermediate chamber 4 to discharge the compressed air leaving the pump chamber 1 through at least one outlet hole 16 in the upper base of the intermediate chamber 4 that constitutes the base 11 of pump chamber 1.

The rotating machine also comprises a noise reduction element 7 comprising at least one damping duct 71 intended to reduce the sound pressure level of the compressed air leaving the pump chamber 1. This noise reduction element 7 is placed in a free space 410 in the intermediate chamber 4, as can be seen, for example, in Figure 1B.

In some embodiments of the invention, as shown in Figures 2A, 2B, 2C, 2D, 2E, 2F, 2G and 2H, the noise reduction element 7 occupies only a part of the free space 410 of the intermediate chamber 4. In these embodiments, the height of the noise reduction element 7 is substantially equal to the height of the internal space of the intermediate chamber 4 (the heights are measured in the direction of the rotor axis). In these embodiments, the intermediate conduit 51 has been shown completely housed in the intermediate chamber 4, connecting the inlet port 5 with an inlet port 15 housed in the base 11 of the pump chamber 1. Figures 2A, 2B and 2C show an embodiment of the noise reduction 7 configured to define an inlet expansion space 411 in the intermediate chamber 4, this inlet expansion space 411 being positioned in the intermediate chamber 4 to be in fluid communication with the outlet port 16 of the pump chamber 1. Preferably, this inlet expansion space 411 is placed below and facing the outlet port 16 so that the outlet port 16 flows directly into this inlet expansion space 411. The Damping 71 of the noise reduction element 7 comprises at least one inlet opening 711 placed in this inlet expansion space 411 so that at least a part of the compressed air exiting the pump chamber 1, through the inlet hole outlet 16, opens and expands into the inlet expansion space 411 and enters the damping duct 71 through the inlet opening 711 and then circulates within the damping duct 71. Preferably, the inlet expansion space 411 is a substantially closed space defined between a recess 72 of the noise reduction element 7 and an inner tubular protrusion 42 of the intermediate chamber 4 so that the easiest exit path for the Compressed air leaving the pump chamber is through the damping line 71.

The noise reduction element 7 comprises a plurality of outlet openings 712 that open to the free space 410 of the intermediate chamber 4 so that the compressed air circulating inside the damping duct 71 is discharged into the free space 410 and enters the exit port 6 to exit to an area outside the rotating machine.

In some embodiments, as shown in Figures 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 an external wall of the noise reduction element 7 and an external protuberance 43 of the intermediate chamber 4, this outlet expansion space 412 being placed over and facing the outlet port 6. The damping duct 71 comprises at least one outlet opening 713 positioned in this outlet expansion space 412 so that a portion of the compressed air circulating inside the damping duct 71 It is discharged into the outlet expansion space 412 and enters the outlet port 6 to exit to an area outside the rotating machine.

The damping duct also comprises a plurality of outlet openings 712 that open into the free space 410 of the intermediate chamber 4 so that a part of the compressed air circulating inside the damping duct 71 is discharged into the free space 410. and enters the exit port 6 to exit to an area outside the rotating machine.

In some embodiments, as shown in Figures 2F and 2H, the noise reduction element 7 comprises a vertical hole 714 orthogonal to the damping duct 71 so that the compressed air is forced to abruptly change its direction (within the noise reduction element). 7) noise reduction to improve noise reduction.

In some embodiments, the noise reduction element 7 comprises an internal expansion area 715 with a cross section larger than the cross section of the damping duct 71 so that the compressed air undergoes expansion within the damping duct 71 to improve noise reduction. noise reduction, as shown in Figure 2G.

Figures 3A and 3B show another embodiment for the noise reduction 7. In this embodiment, the noise reduction element 7 comprises a cylindrical projection 73 surrounding the inlet opening 711 of the damping duct 71 so that the protuberance 73 is directly connects with the outlet hole 16 of the pump chamber 1. Thus, the height of the noise reduction element 7 may be less than the height of the internal space of the intermediate chamber 4 (the heights are measured in the direction of the axis of the rotor). In this embodiment, the compressed air leaving the pump chamber 1 (through the outlet hole 16) directly enters the inlet opening 711 of the damping duct 71 without passing through the free space 410 of the intermediate chamber 4. The damping duct 71 also comprises a plurality of outlet openings 712 that open into the free space 410 of the intermediate chamber 4 so that the compressed air circulating inside the damping duct 71 is discharged into the free space 410 and It then enters the exit port 6 to exit to an area outside the rotating machine.

In an embodiment shown in Figures 4A, 4B and 4C, the noise reduction element 7 is configured and mounted in the intermediate chamber 4 so that an inlet opening 711 of the damping duct 71 faces the outlet hole 16 of the pump chamber 1 establishing a connection between the outlet port 16 and the inlet opening 711 of the damping duct 71. In this embodiment, the noise reduction element 7 (or at least a part of the noise reduction element) can be in contact with the base of the pump chamber 1. In this embodiment the noise reduction element 7 comprises the outlet port 6 so that the damping duct 71 discharges the compressed air directly to the outside area without passing through through the free space 410 of the intermediate chamber 4.

Figures 5A and 5B show an embodiment of a noise reduction element 7 that occupies the entire free space 410 of the intermediate chamber 4. The noise reduction element 7 is configured and mounted in the intermediate chamber 4 so that an opening The inlet opening 711 of the damping duct 71 faces the outlet opening 16 of the pump chamber 1 establishing a connection between the outlet opening 16 and the inlet opening 711 of the damping duct 71. In this embodiment the reduction element Noise 7 comprises the outlet port 6 so that the damping duct 71 discharges the compressed air directly to the outer area without passing through the free space 410 of the intermediate chamber 4.

In one embodiment shown in Figures 6A, 6B and 6C the damping conduit 71 is a labyrinth conduit. The noise reduction element 7 comprises several walls 74 that define the 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 a start point 741 of the labyrinth, in communication with the exit port 16 of the pump chamber, and a termination point 742 of the labyrinth in communication with the exit port 6. In this embodiment, the noise reduction element 7 comprises the outlet port 6 so that the damping duct 71 discharges the compressed air directly to the outer area without passing through the intermediate chamber 4.

The embodiment shown in Figures 7A and 7B shows a noise reduction element 7 comprising several walls 74 defining the labyrinth duct. These walls 74 are mounted or integrated into the upper wall of the intermediate chamber 4 and housed in the intermediate chamber 4. Figure 7B shows the path followed by the compressed air between a starting point 741 of the labyrinth, in communication with the opening orifice. outlet 16 of the pump chamber, and a termination point 742 of the labyrinth in communication with the outlet port 6. In this embodiment, the noise reduction element 7 comprises the outlet port 6 so that the damping duct 71 It discharges the compressed air directly to the exterior area without passing through the intermediate chamber 4.

In the embodiments shown in Figures 8A, 8B and 8C, the noise reduction element 7 comprises several walls 74 that define the labyrinth duct. In this embodiment a first part 743 of the walls is integrated into the upper wall of the intermediate chamber 4 and a second part 744 of the walls is integrated into the base 21 of the motor 2. Figure 7B shows the path followed by the compressed air between a start point 741 of the labyrinth, in communication with the exit port 16 of the pump chamber, and a termination point 742 of the labyrinth in communication with the exit port 6. In this embodiment, the noise reduction element 7 comprises the outlet port 6 so that the damping duct 71 discharges the compressed air directly to the outer area without passing through the intermediate chamber 4.

In this text, the term "comprises" and its derivatives (such as "understanding", etc.) should not be understood in an exclusive sense, that is, these terms should not be interpreted as excluding the possibility that what is described and defined may include additional elements, stages, etc.

The present invention is obviously not limited to the specific embodiments described herein, but also encompasses any variations that any person skilled in the art may consider (for example, regarding the choice of materials, dimensions, components, configuration , etc.), within the general scope of the invention, as defined in the claims.

Claims (15)

1. A rotating machine comprising a pump chamber (1) comprising a base (11), a cover (12) and a side wall (13) defining an interior space; a rotor (14) housed in the interior space of the pump chamber (1), this rotor (14) comprising at least one slot (141); at least one vane (142), each vane (142) being at least partially inserted into a slot (141) of the rotor (14); an electric motor (2) having a drive shaft (3) passing through a central opening in the base (11) to drive the rotor (14); at least one inlet port (5) for sucking air from a device where the pressure is intended to be reduced, the inlet port being in fluid communication with at least one inlet hole (15) of the pump chamber (1), at least one outlet port (6) in fluid communication with an external area of the rotating machine to discharge the compressed air leaving the pump chamber (1) through at least one outlet hole (16) of the chamber pump (1), a noise reduction element (7) comprising at least one damping duct (71) intended to reduce the sound pressure level of the compressed air an intermediate chamber (4) between the base (11) of the pump chamber (1) and the motor (2), the inlet port (5) and the outlet port (6) being connected to this intermediate chamber (4). ), characterized by comprising an intermediate duct (51) housed at least partially in the intermediate chamber (4) to communicate the inlet port (5) with the at least one inlet hole (15) of the pump chamber, leaving the intermediate duct (51) a free space (410) in the intermediate chamber (4) and the noise reduction element (7) being placed at least partially within a part of this free space (410), and where the at least one outlet hole (16) flows into this free space (410) of the intermediate chamber (4) so that the compressed air leaving the pump chamber (1) through the outlet hole (16) enters the exhaust duct. damping (71) of the noise reduction element (7). 2. Rotary machine according to claim 1, wherein the noise reduction element (7) comprises at least one outlet opening (712) that opens into the free space (410) of the intermediate chamber (4) so that at least part of the compressed air circulating inside the damping duct (71) is discharged into the free space (410) and enters the outlet port (6) to exit to an area outside the rotating machine. 3. Rotary machine according to any of the preceding claims, wherein the noise reduction element (7) is configured so that an inlet opening (711) of the damping duct (71) faces the outlet hole ( 16) of the pump chamber establishing a connection between the outlet hole (16) and the inlet hole (15). 4. Rotary machine according to claim 3, wherein the noise reduction element (7) comprises a projection (73) surrounding the inlet opening (711) of the damping duct (71) so that the projection connects directly with the outlet hole (16) of the pump chamber (1). 5. Rotary machine according to claims 1 or 2, wherein the noise reduction element (7) defines an inlet expansion space (411) in the intermediate chamber (4) in fluid communication with the outlet orifice ( 16) of the pump chamber (1) and where the damping duct (71) comprises at least one inlet opening (711) placed in this inlet expansion space (411) so that the compressed air coming out of The pump chamber (1), through the outlet hole (16), opens and expands into the inlet expansion space (411) and at least a part enters the damping duct (71) through the inlet opening (711) and circulates inside the damping duct (71). 6. Rotating machine according to any of the preceding claims, wherein the noise reduction element (7) defines an outlet expansion space (412) in the intermediate chamber (4) in fluid communication with the outlet port ( 6) and wherein the damping duct (71) comprises at least one outlet opening (713) placed in the outlet expansion space (412) so that the compressed air circulating within the damping duct (71) discharges in the exit expansion space (412). 7. Rotating machine according to any of the preceding claims, wherein the noise reduction element (7) comprises a hole (714) orthogonal to the damping duct (71). 8. Rotating machine according to any of the preceding claims, wherein the noise reduction element (7) comprises an internal expansion zone (715) of cross section greater than the cross section of the damping duct (71). 9. Rotating machine according to any of claims 1, 2, 3, 4, 5, 7 or 8, wherein the noise reduction element comprises the output port (6). 10. Rotary machine according to any of the preceding claims, wherein the damping duct (71) is mounted or integrated at least partially in the base (11) of the pump chamber (1) or upper base of the intermediate chamber (4) and housed in the intermediate chamber (4). 11. Rotating machine according to any of the preceding claims, wherein the damping duct (71) is mounted or integrated at least partially in a base (21) of the motor (2). 12. Rotary machine according to any of the preceding claims, wherein the damping duct (71) comprises a serpentine or labyrinthine duct. 13. Rotary machine according to claim 12, wherein the noise reduction element (7) may comprise several walls (74) that define the labyrinth duct. 14. Rotary machine according to claim 13, wherein a first part (743) of the walls (74) is integrated into the base (11) of the pump chamber (1) or upper base of the intermediate chamber (4). ) and housed in the intermediate chamber 4 and a second part (744) of the walls (74) is integrated into the base 21 of the motor 2. 15. Rotary machine according to any of the preceding claims, wherein the noise reduction element comprises a noise damping material.