RU2767859C1 - Exhaust unit for installation in the duct - Google Patents

Abstract

FIELD: production sector.

SUBSTANCE: invention relates to the industry associated with the production of exhaust units installed in air ducts. The exhaust unit is designed for installation inside the air duct and includes: an impeller (1) having a base (1.1) and blades (1.2), with the blades (1.2) protruding from the base (1.1); a drive element (2) for imparting a torque to the impeller (1) so that it creates an air flow through the blades (1.2); a support (3) having a first surface (3.1) and a second surface (3.2), the first surface (3.1) being intended for fixed placement of the drive element (2); housing (4) consisting of a first part (4.1) and a second part (4.2) to surround the impeller (1), drive element (2) and support (3). The support (3) contains: an inner wall (3.3), which, together with the first surface (3.1), limits the body (6) to accommodate the drive element (2); an outer wall (3.4) located radially outside of the inner wall (3.3), so that the walls (3.3, 3.4) delimit the passage (7) for the movement of air. When the suction unit is installed in the position of use, the outer wall (3.4) comes into radial and internal contact with the first part (4.1) and the second part (4.2), as well as with the area (J) of the connection of the first part (4.1) and the second part (4.2) with each other, so that the air outlet along the outer wall (3.4) becomes blocked.

EFFECT: reduction of noise generated by the passage of air through the exhaust device.

15 cl, 17 dwg

Description

The field of technology to which the invention belongs

The invention relates to the industry associated with the production of exhaust units installed in air ducts.

State of the art

Currently, exhaust units installed in air ducts are widely known. Such exhaust units have an impeller with blades, an electric motor for rotating the impeller so that air flow or movement is created with its blades, a support for accommodating a motor fixed inside the exhaust unit, and an outer casing, which is a common casing.

Said exhaust units generating said air flow or movement create an annoying noise. Basically, this noise occurs as a result of the movement of air in the exhaust units.

In turn, this noise is largely due to the fact that the air is not moving in a completely continuous or uniform manner, but is generated in discontinuities that result in point contacts with the outer casing, usually at an irregular frequency. This disadvantage is seriously exacerbated in the case of metal outer casings.

In view of the described disadvantages or limitations inherent in the currently used solutions, a solution is needed to reduce the noise that occurs when air passes through the exhaust device.

Disclosure of invention

In order to achieve the stated goal and solve the technical problems present today, as well as to provide additional benefits that can be obtained later, the present invention proposes an exhaust unit for installation inside the duct.

The exhaust assembly includes an impeller having a base and blades protruding from the base, and, in addition, additionally has a screen to prevent air from contacting the housing along the blades.

The exhaust assembly further includes a drive member for imparting a torque to the impeller so that it creates an air flow through the blades; a support having a first surface and a second surface, and the first surface is intended for a fixed installation of the drive element; and, a housing including a first part and a second part for surrounding the impeller, the drive member, and the support.

The support includes an inner wall which, together with the first surface, defines a housing for receiving the drive element; and an outer wall which is positioned radially outward relative to the inner wall such that the walls define a passage for air movement.

Thus, when the exhaust unit is installed in the position of use, the outer wall comes into radial and internal contact with the first part and the second part of the housing, as well as with the area of connection of the first part and the second part with each other, so that the air outlet along the outer wall is blocked . Thus, the exit of noise through said connection area is also blocked.

In a preferred embodiment, the outer wall is in contact with the entire joint area. Moreover, said connection area is preferably formed by an overlap between the first part and the second body part.

In a preferred embodiment, the support has ribs in the passage to guide the air flow. Accordingly, the fins are preferably curved in order to eliminate the tangential component of the airflow generated by the blades so that the airflow can be guided in a straight path.

The drive element is fixedly located in the support, and the impeller is connected to the drive element, while between the base and the inner wall there is a separating gap for air inlet into the drive element.

The exhaust assembly may include a cover located along the second surface of the support in such a way that it defines the continuation of the passage. Accordingly, the lid in the preferred embodiment has a concave side to cover the exhaust assembly components and a convex side to guide air.

The exhaust unit may have a channel connecting the outer part of the housing with the housing. Accordingly, the channel preferably has a first portion protruding outward from the outer wall, and each of the body parts has a slot for co-forming an opening to receive the first channel portion.

The exhaust assembly may include a blocking element positioned to prevent air from moving between the casing and the impeller screen and to direct air entering the casing between the screen and the base.

In a preferred embodiment, the housing is made of a metallic material. Additionally or alternatively, the support is preferably made of a plastic material. Additionally or alternatively to any of the above, the impeller in the preferred embodiment is made of plastic.

Brief description of the drawings

At the top of Fig. 1 shows a prior art exhaust assembly and, at the bottom, an exhaust assembly according to the present invention.

In FIG. 2 is an exploded view of an exhaust assembly according to the present invention for installation inside a duct.

In FIG. 3 and 4 are schematic perspective views of an exhaust assembly according to the present invention.

In FIG. 5 and 7 are schematic side views of the exhaust unit according to the invention, while FIG. 6 and 8 show rear and front views, respectively.

In FIG. 9 is a schematic longitudinal sectional view of the suction unit according to the invention in a position of use.

In FIG. 10A and 10B show schematic views of an impeller of an exhaust assembly according to the present invention.

In FIG. 11 and 12 are schematic perspective views of a support that is part of an exhaust assembly according to the present invention.

In FIG. 13 and 15 are schematic rear and front views of the support, respectively; while in FIG. 14 and 16 show a schematic side view and a schematic side sectional view of said support, respectively.

Implementation of the invention

The present invention relates to an exhaust device installed inside an air duct, which includes an impeller (1), a drive element (2), a support (3) and a housing (4), which has a first part (4.1) and a second part (4.2), to surround the impeller (1), drive element (2) and support (3) as a common housing.

The impeller (1) has a base (1.1) and blades (1.2), with the blades (1.2) protruding from the base (1.1). The base (1.1) has a contact surface (1.1') configured to contact part of the air that enters the impeller (1) and hence the exhaust unit. The impeller (1) is visible in Fig. 2, 10A and 10B.

Such a configuration of the base (1) ensures that the air is directed towards the inner periphery of the exhaust unit, in other words, towards the part radially and externally removed from the imaginary central longitudinal axis (X) of the exhaust unit, minimizing the influence or obstruction of the movement of air along the body (4) through its internal part. Accordingly, said contact surface (1.1') has a convex shape.

The drive element (2) in this case is an electric motor installed to impart a torque to the impeller (1) so that it creates an air flow using the blades (1.2). The drive element (2) is visible in FIG. 2 and 9.

Accordingly, the impeller (1), and more specifically, its base (1.1) is mechanically connected to the drive element (2) to receive a torque from it. Said air flow, created by the rotational movement of the blades (1.2), moves along the exhaust unit.

The support (3) has a first surface (3.1) and a second surface (3.2), with the first surface (3.1) opposite the first surface (3.2). The first surface (3.1) is intended for the fixed placement of the drive element (2). Support (3) is visible in Fig. 11-16.

The drive element (2) is fixedly mounted on the said first surface (3.1) of the support (3) by means of a threaded connection. Similarly, preferably between the drive element (2) and said first surface (3.1) a shock absorber or vibration damping element (5) is installed. Accordingly, the fixed fastening of the drive element (2) on the first surface (3.1) is made through the damper (5), which, in turn, is attached to the said first surface (3.1) using an exhaust unit.

The support (3) additionally has an inner wall (3.3) perpendicular or substantially perpendicular to the first surface (3.1) for attaching the drive element (2). Preferably, the inner wall (3.3) extends parallel to an imaginary central longitudinal axis (X) of the exhaust unit. Likewise, it is preferred that said inner wall (3.3) has such a geometric shape, preferably cylindrical, that it defines the body (6).

The first surface (3.1) of the support (3) is limited around the perimeter by the aforementioned inner wall (3.3). Thus, the housing (6) is defined radially and externally or around the perimeter by the inner wall (3.3) and axially or longitudinally by the first surface (3.1).

Said housing (6) has an opening at the longitudinal end opposite the inner wall (3.1) through which the drive element (2) protrudes at its connection with the impeller (1), in other words, the inner wall (3.3) and the first surface (3.1) limit the body (6), the latter being open.

The support (3) additionally has an outer wall (3.4) which is located radially and externally with respect to the inner wall (3.3). Likewise, it is preferred that the outer wall (3.4) has a geometric shape, preferably cylindrical. Thus, it is preferred that said outer wall (3.4) be parallel or substantially parallel to the inner wall (3.3). Accordingly, the inner wall (3.3) and the outer wall (3.4) are located at a radial distance from each other in such a way that they define a passage (7) for air movement.

The inner wall (3.3) and the outer wall (3.4) are connected together by means of ribs (3.5) located in the support (3). These ribs (3.5), in addition to acting as a connecting element between the two said walls (3.3, 3.4), act as guiding elements for the air or air flow generated by the impeller (1), at the same time they define the gap between the walls, which is the passage ( 7).

Preferably, the fins (3.5) are curved. Said air flow created by the impeller (1) due to its rotation exits it in the form of a helical flow, in other words, describing a spiral. In other words, the air flow has a velocity with a tangential component as it exits the impeller (1). Accordingly, the ribs (3.5) are set to eliminate said tangential component, so that the air is guided in a linear or straight line, while the air speed and pressure increase.

In the preferred embodiment, the outer wall (3.4) is smooth, continuous and uniform, in other words, it has no through holes. Likewise, it is also preferable that the inner wall (3.3) is equally smooth, continuous and uniform, in other words without through holes in the radial direction.

When the drive element (2) is properly fixed on the support (3) along the housing (6) and the impeller (1) is mechanically connected to the drive element (2) to obtain torque from the latter in order to generate airflow, the configuration and location of the impeller ( 1) and the outer wall (3.4) are such that the air flow exits from the impeller (1) driven in such a way that the flow is directed partly essentially parallel to the outer wall (3.4) and partly against said outer wall (3.4).

Through such a configuration and arrangement, which can be obtained in light of FIG. 9, at least a large part of the generated air flow is prevented from contacting the housing (4) both when leaving the impeller (1) and when the flow moves forward or moves longitudinally and parallel to the imaginary central longitudinal axis (X) of the exhaust unit.

Preferably, with such a configuration and arrangement, the proportion of the generated airflow that comes into contact with the casing (4) as it exits the impeller (1) is zero or at least negligible in terms of the noise it generates. Likewise, the proportion of air flow that can be generated and contacted with the housing (4) when advancing or moving longitudinally and parallel to the imaginary central longitudinal axis (X) of the exhaust unit is also zero or at least negligible in terms of generated noise.

The base (1.1) of the impeller (1) has a flange or contour (1.1'') which, when the drive element (2) is suitably fixed on a support (3) in the housing (6) and the impeller (1) is mechanically connected to the drive element (2) to obtain torque from the latter and create an air flow, remained aligned or substantially aligned with the inner wall (3.3) of the support (3). In addition, said flange or contour (1.1'') has a longitudinal extension aligned with said inner wall (3.3).

Accordingly, between the aforementioned contour (1.1'') and the longitudinal end of the inner wall (3.3) there is a separating gap (S) for controlled air inlet into the housing (6). The separating gap (S) is therefore configured to allow the drive element (2) to be cooled by a controlled and reduced portion of the air flow generated by the impeller (1).

The second surface (3.2) of the support (3) is configured to accommodate additional components (8) that are involved in the operation of the exhaust unit. In FIG. 2 and 9 show one of these components (8), which is a capacitor.

The suction unit according to the invention has a cover (9) which, in the position of use, should be located along the second surface (3.2) of the support (3) so that it defines the continuation of the passage (7). Preferably, said cover (9) is connected to the support (3) by threaded connections, although in an alternative embodiment it can be connected by clamping or snap-on connection points.

In addition, the cover (9) is made in such a way that it has a concave side covering the components (8) of the exhaust unit located along the second surface (3.2), and a convex side that guides the air. Accordingly, said cover (9) has a perimeter edge (9.1) of such a size that it is equal to or smaller, in terms of radial measurement, to the size of the geometric shape of the inner wall (3.3). See fig. nine.

In a preferred embodiment, the lid (9) is connected to the support (3) in such a way that the perimeter edge (9.1) is positioned in such a way that it defines an extension of the inner wall (3.3) in a direction longitudinal and parallel to an imaginary central longitudinal axis (X) exhaust unit. This prevents the formation of turbulence in the air flow created by the impeller (1) when the flow moves along the end of the inner wall (3.3) in accordance with the direction of movement or movement of said air flow. Such an arrangement or configuration is clearly seen in FIG. nine.

In addition, the cover (9) is defined in such a way that it has a convex side to guide the air. In other words, it smoothes the path of the air flow after passing through the passage (7) towards the radially more inward area to exit the exhaust unit.

Accordingly, said cover (9) has a curved edge (9.2) on said convex side, having such dimensions that it determines a gradual, in other words, without jumps, decrease in the radial dimension or measurement relative to said imaginary central longitudinal axis (X) of the cover (9) . Thus, the cover (9) prevents the formation of turbulence or pressure changes that impede or reduce the flow of air at the outlet of the exhaust unit, or at least direct it to a radially more inward region after the air has passed through the passage (7) to exit the exhaust unit. .

As mentioned earlier, the body (4) includes the first part (4.1) and the second part (4.2). Preferably, said parts (4.1, 4.2) are provided connected together, each of which defines the longitudinal end of the draw unit, as can be clearly seen, for example, in FIG. 2, although they may alternatively be provided separately, each defining a longitudinal half of said assembly.

The first part (4.1) and the second part (4.2) are connected together in the joint area (J) located along the outer wall (3.4). More specifically, the outer wall (3.4) is located in contact with the first part (4.1) and the second part (4.2) both near the area (J) of their connection, and along the very area (J) of the connection, which is formed by the overlap of the said parts (4.1 , 4.2).

In accordance with the above preferred embodiment, in which each of the parts (4.1, 4.2) defines one of the longitudinal ends of the draw unit, the connection area (J) is entirely, in other words, completely located along and in contact with the outer wall (3.4), which follows from Fig. 2 and 9. Thus, it contributes to the creation of a tight connection or seal between the above-mentioned parts (4.1, 4.2) of the body (4), so that the leakage or escape of air through the said area (J) of the connection is prevented.

The first part (4.1) and the second part (4.2) have a first step (4.1', 4.2') in the longitudinal part parallel or substantially parallel to an imaginary central longitudinal axis (X) of the longitudinally located outer wall (3.4). In addition, said first steps (4.1', 4.2') are defined in such a way that the inner surface of the outer wall (3.4), opposite to that which is in contact with the housing (4), is aligned or provides continuity with the inner surface of the housing (4) , in other words, with segments (4.1, 4.2). See fig. nine.

This prevents the formation of turbulence in the air flow created by the impeller (1) when the flow moves along both the beginning of the outer wall (3.4) and the end of this wall (3.4) in accordance with the direction of movement or movement of the said air flow.

In addition, one of the parts (4.1, 4.2) has a second step (10) to overlap with the corresponding longitudinal end of the other part (4.2, 4.1) to improve tightness, in other words, to prevent air and noise from escaping. In this case, one connection area (J) is defined or defined by this overlap, as also described previously.

The housing (4) has an inlet (11) and an outlet (12). In a preferred embodiment, the inlet (11) is located entirely in the first part (4.1) and the outlet (12) is completely located in the second part (4.2). Likewise, the inlet (11) defines an inlet for air drawn into the exhaust unit by the impeller (1), and the outlet (12) defines an outlet for the air flow generated or created by the impeller (1) of the exhaust unit.

These necks (11, 12) are configured to connect to an air duct, which is not the object of the present invention. Similarly, the parts (4.1, 4.2) of the body (4) have smaller dimensions in said necks (11, 12), in other words, a smaller inner diameter.

Thus, therefore, the body (4) has portions (4') of varying diameter. Accordingly, the housing (4) has one section (4') with a variable diameter immediately after the inlet mouth (11) and another section (4') with a variable diameter immediately before the outlet neck (11) in accordance with the advancement or direction of the air flow, which can be generated by the impeller (1).

If necessary, the outer wall (3.4) of the support (3) extends in such a way that it radially and internally encloses the housing (4) also along a section (4') with a varying diameter located immediately before the outlet neck (12).

Along each of the necks (11, 12), radially and outside of them, the exhaust unit has a seal (13) to ensure tightness to prevent air leakage from the duct and the exhaust unit itself.

When the exhaust unit is installed, or at least parts (4.1, 4.2) of the body (4) are connected together in the connection area (J) along the outer wall (3.4) of the support (3), the necks (11, 12) are located concentrically with respect to an imaginary central longitudinal axis (X), having a smaller diameter relative to said outer wall (3.4) and furthermore preferably relative to the inner wall (3.3). Thus, both the inlet of air into the exhaust unit and the outlet of air from it are beneficial.

In the preferred embodiment, and as can be clearly seen in FIG. 10A and 10B, the impeller (1) additionally has a screen (1.3). This screen (1.3) expands in the longitudinal direction, so that at each point along it it has a different diametral dimension. In other words, the screen (1.3) has open longitudinal ends, each of which has a different diameter than the other, in accordance with a preferably progressive change.

The open longitudinal end located opposite the inlet mouth (11) has a smaller diameter than the open longitudinal end located opposite the drive element (2). In accordance with the gradual, preferably linear change in the diameter of said screen (1.3), the latter is configured in such a way as to be parallel, or essentially parallel to the body (4) along the corresponding diameter change section (4').

When the exhaust unit is installed, for example, in accordance with the state shown in FIG. 9, said baffle (1.3) prevents or blocks air from contacting the body (4) and, more particularly, the variable diameter portion (4') immediately after the inlet (11).

This screen (1.3) very effectively reduces the noise generated by the exhaust unit during operation, due to the fact that it prevents air from contacting the housing (4) in a critical area, since this is the activation area of the impeller (1), which is the area where, with on the one hand, air is sucked in, and on the other hand, an air flow is generated, which must be moved or driven along the exhaust unit.

To optimize the intake of air into the impeller (1) through the open longitudinal end located opposite the inlet mouth (11), the diameter of said open end is equal to or greater, preferably greater than the diameter of the inlet throat (11).

In order to further optimize the intake of air into the impeller (1) through the open longitudinal end located opposite the inlet mouth (11), the exhaust assembly preferably includes a blocking element (14). The blocking element (14), visible in FIG. 9 is located in a place blocking the air passage between the housing (4) and the screen (1.3) of the impeller (1) when said air is admitted into the exhaust unit, and more specifically, into the impeller (1).

Accordingly, said blocking element (14) is connected to the housing (4) by its inner part, as seen in FIG. 9. In this way, the blocking element (14) forces the air that enters the exhaust unit through the inlet (11) to pass to the impeller (1). Said blocking element (14) is stationary, which favors the reduction of the level of generated noise.

Additionally and preferably, the blocking element (14) is fixed in the housing (4), in addition to being partially inserted into the impeller (1) through the open longitudinal end opposite the inlet (11). See, again, the aforementioned FIG. nine.

The open longitudinal end of the screen (1.3) with a large diameter, located opposite the drive element (2), has a diameter greater than the diameter of the flange (1.1'') of the base (1.1), and also greater than the diameter of the longitudinal extension aligned with the inner wall (3.3). These diameters are considered in terms of radii about an imaginary central longitudinal axis (X) of the exhaust unit.

Thus, by providing a gap between the base (1.1) and the screen (1.3) of the impeller (1), due to the described difference in diameters, a smoother path is provided for the air driven by the blades (1.2) on leaving them. Thus, the path is more parallel to the imaginary central longitudinal axis (X) of the draw unit and has fewer changes in direction, with the changes in direction being additionally less abrupt. See the arrows on the exhaust assembly shown in FIG. one.

This configuration, in addition to providing a lower noise level, is characterized by smaller diametric measurements of the suction unit for some of the hallmarks of the impeller (1), such as flow and pressure. This makes it possible to install the suction unit in spaces smaller than in other cases, depending on the mentioned features of the impeller (1). See, for example, FIG. 1, which shows a longitudinal section of the exhaust unit according to the present invention (lower part of the drawing) and a view of a conventional exhaust unit (upper part of the drawing) with the same flow and pressure characteristics.

Proposed in the present invention, the exhaust unit includes a channel (15)connecting the outer part of the housing (4) and, therefore, the exhaust unit, with the housing (6). Thus, the channel (15) acts as a wire passage element to electrically connect the electrical box (16) present on the exhaust unit and located on the outer part of the housing (4) with the drive element (2). Said channel (15) is visible in FIG. 16.

Said channel (15) has a first section (15.1) protruding outward from the outer wall (3.4). In addition, the channel (15) has a second section (15.2), which passes through the passage (7) in such a way that it reaches the housing (6).

Accordingly, each of the mentioned parts (4.1, 4.2) of the body (4) has a groove (17) open at one end to receive the said first section (15.1) of the channel (15) so that together both of the above parts (4.1, 4.2) and more specifically, both of the aforementioned grooves (17) enclose or surround the first section (15.1). Thus, said first section (15.1) acts as an element of unambiguous positioning of the parts (4.1, 4.2) of the body (4) relative to each other.

According to a preferred embodiment of the invention, the exhaust unit according to the present invention is intended for installation in aggressive environments, for which the technical standards require that the housing (4) be made of metal. These environments, according to technical standards, require that the exhaust unit is resistant to shock, fire, etc. Accordingly, the elements, the configuration and the arrangement of these elements are of particular importance in order to provide an effective and noticeable reduction in the noise generated when using the exhaust unit.

According to the preferred embodiment of the invention described, the support (3) is preferably made of a plastic material in order to reduce the overall weight of the suction unit.

In continuation of the described preferred embodiment of the invention, the impeller (1) is preferably made of a plastic material in order to, among other things, reduce the overall weight of the exhaust unit, reduce the noise generated by the creation of the air flow directed to the outlet (12), and increase the performance of the exhaust assembly, on the one hand, due to the reduction in weight due to the production of plastic material instead of metal, and, on the other hand, due to the special geometry proportional to the blades (1.2), since the impeller is made of plastic and not metal, of course, in limited time and manufacturing cost.

Claims (23)

1. Exhaust unit designed for installation inside the duct, including: - an impeller (1) having a base (1.1) and blades (1.2), the blades (1.2) protruding from the base (1.1); - a drive element (2) for imparting a torque to the impeller (1) so that it creates an air flow through the blades (1.2); - a support (3) having a first surface (3.1) and a second surface (3.2), the first surface (3.1) being intended for the fixed placement of the drive element (2); - a housing (4) consisting of a first part (4.1) and a second part (4.2) to surround the impeller (1), the drive element (2) and the support (3); in which the support (3) contains: - an inner wall (3.3), which, together with the first surface (3.1), defines the housing (6) to accommodate the drive element (2); And - an outer wall (3.4) located radially outside of the inner wall (3.3), so that the walls (3.3, 3.4) delimit the passage (7) for air movement; in which, when the exhaust unit is installed in the position of use, the outer wall (3.4) comes into radial and internal contact with the first part (4.1) and the second part (4.2), as well as with the area (J) of the connection of the first part (4.1) and the second parts (4.2) with each other so that the air outlet along the outer wall (3.4) becomes blocked. 2. An assembly according to claim 1, in which the outer wall (3.4) is in contact with the entire joint area (J). 3. A node according to claim 1 or 2, in which the connection area (J) is formed by an overlap between the first part (4.1) and the second part (4.2). 4. Node according to any one of paragraphs. 1-3, in which the support (3) has ribs (3.5) in the passage (7) for directing the air flow. 5. An assembly according to claim 4, in which the ribs (3.5) are bent to eliminate the tangential component of the air flow generated by the blades (1.2), so that the air flow can be directed along a straight path. 6. Node according to any one of paragraphs. 1-4, in which, when the drive element (2) is fixed in the support (3) and the impeller (1) is connected to the drive element (2), there is a separating gap (S) between the base (1.1) and the inner wall (3.3) for air inlet into the drive element (2). 7. Node according to any one of paragraphs. 1-5, further including a cover (9) located along the second surface (3.2) of the support (3) in such a way that the cover defines the continuation of the passage (7). 8. Assembly according to claim 7, in which the cover (9) has a concave side for closing the components (8) of the exhaust assembly and a convex side for directing air. 9. Node according to any one of paragraphs. 1-8, further including a channel (15) providing communication of the outer part of the body (4) with the body (6). 10. The node according to claim 9, in which the channel (15) has a first part (15.1) protruding outward relative to the outer wall (3.4), and each of the parts (4.1, 4.2) of the body (4) has a groove (17) for joint forming a hole for receiving the first part (15.1). 11. Node according to any one of paragraphs. 1-10, in which the impeller (1) additionally contains a screen (1.3) that prevents air from contacting the housing (4) along the blades (1.2). 12. The assembly according to claim 11, further comprising a blocking element (14) designed to prevent air from moving between the housing (4) and the screen (1.3), so that the air entering the housing (4) is directed between the screen (1.3 ) and base (1.1). 13. Node according to any one of paragraphs. 1-12, in which the housing (4) is made of a metallic material. 14. Node according to any one of paragraphs. 1-13, in which the support (3) is made of plastic material. 15. Node according to any one of paragraphs. 1-14, in which the impeller (1) is made of plastic material.

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