CN210087660U

CN210087660U - Turbine with housing and building ventilation system

Info

Publication number: CN210087660U
Application number: CN201790001366.8U
Authority: CN
Inventors: A·弗莱格
Original assignee: Ebm Papst St Georgen GmbH and Co KG
Current assignee: Ebm Papst St Georgen GmbH and Co KG
Priority date: 2016-11-16
Filing date: 2017-11-09
Publication date: 2020-02-18
Anticipated expiration: 2027-11-09
Also published as: DE102016013639A1; EP3542066B1; EP3542066A1; WO2018091131A1

Abstract

The utility model relates to a turbine and building ventilation system with casing. The housing of the turbomachine comprises a first housing part (14, 17; 32,45) having a central chamber (13) and an outer chamber (16) extending around the central chamber (13). The first fan wheel (6) is accommodated in a central chamber (13) of the first housing part (14, 17; 32,45) and can be driven in rotation about an axis (9). The first housing part (14, 17; 32,45) and the second housing part (18, 19; 43,46) are distributed on different sides of a cross-section (A) perpendicular to the axis (9). The housing includes a first passage (22) extending from the central chamber (13) and a second passage (23) extending from the outer chamber (16). The two channels (22,23) are transverse to a plane perpendicular to the section (A) of the axis (9) of the housing.

Description

Turbine with housing and building ventilation system

Technical Field

The present invention relates to a turbine for simultaneously driving fluid flows, in particular air flows, in opposite directions. The turbine is particularly suitable for the ventilation of spaces which are not connected to the environment or have only a narrow connecting channel to the environment, while pressure differences to the environment are avoided.

Background

DE 102008031084 discloses a dual flow fan in which there are two annular arrays of air flow on the fan wheel, which differ in their chirality so that as the fan wheel rotates, they drive the air flow in opposite directions. The fan has a problem in that the counter-rotating airflows cannot be separated from each other.

DE 102014118210 a1 discloses a dual flow fan which allows for the separation of counter-rotating air flows. The fan has a special fan blade with fluid inlets at opposite ends; through the internal channels of the fan wheel, the counter-rotating air flows are guided past each other and are again output through the fluid outlets on the circumference of the fan wheel. The space requirement of the internal passage means that the fluid inlet can only occupy approximately half the area of the front side of the fan wheel. Thus, the throughput of the fan is much less than that of a single flow fan having the same diameter. The walls of the fan duct must be thick enough to withstand the centrifugal forces generated during operation. Thus, throughput cannot be increased by increasing the fan wheel speed without simultaneously reducing the free cross-section of the channels and increasing the rotational inertia of the fan.

SUMMERY OF THE UTILITY MODEL

The utility model provides a double-flow turbine, its low in manufacturing cost realizes high throughput under limited diameter and speed.

According to the invention, this object is achieved by: there is provided a turbine having a housing, the housing of the turbine comprising a first housing part having a central chamber and an outer chamber extending around the central chamber, and a first fan wheel located in the central chamber and driven in rotation about an axis, wherein the first and second housing parts are located on different sides of a cross-section perpendicular to the axis, wherein the central chamber of the second housing part contains a second fan wheel driven in rotation about the axis, and an outer chamber extending around the axis and the central chamber, wherein the housing comprises a first channel connecting the central chamber of the first housing part to the outer chamber of the second housing part, and a second channel connecting the outer chamber of the first housing part and the central chamber of the second housing part, wherein the first and second channels cross a cross-section of the housing, wherein the first and second fan wheels are mounted on a common shaft and mirror-inverted, and wherein the first channel is optimally separated from the central chamber of the second housing portion and/or the outer chamber of the first housing portion by a partition extending towards a conical surface expanding outwardly from the second housing portion.

Preferably, the two ends of the axis in the cross-section should be point-reflection mirror-symmetrical from the first channel to the second channel.

Preferably, a plurality of said first channels and a plurality of said second channels are alternately rounded around said axis.

Preferably, the housing comprises two identical internal parts opposite each other on both sides of the cross-section and comprises a partition separating the second channel from the central chamber of the first housing part and a partition separating the first channel from the outer chamber of the second housing part.

Preferably, at least one motor is accommodated for driving the first fan wheel and the second fan wheel and is located between the first fan wheel and the second fan wheel.

Preferably, the motor is mounted on an internal component.

Preferably, the housing comprises two identical outer parts in which the first and second fan wheels are engaged.

Preferably, the first fan wheel and the second fan wheel can have a hub in the shape of a conical peg widening out towards the cross section.

Preferably, the blades of the first and second fan wheels protrude radially from the outer circumferential surface of the hub.

Preferably, the number of vanes of each first fan wheel and said second fan wheel and the number of said first channels and said second channels extending from the central chamber housing the first fan wheel and said second fan wheel should be coprime.

Preferably, the diameter of the partition between the central chamber and the outer chambers of the first and second housing parts increases towards the cross-section.

Preferably, the first fan wheel and the second fan wheel have the same structure and are rotationally driven in opposite directions.

Preferably, the size of the partition separating the first channel from the second channel is larger than the size of the first channel and the second channel perpendicular to the partition in at least one spatial direction.

According to the utility model discloses, still provide a building ventilation system including above-mentioned turbine.

The purpose of the utility model is realized through the following mode: the turbine includes a housing including a first housing portion having a central chamber and an outer chamber extending around the central chamber, and a first fan wheel received in the central chamber of the first portion of the housing and rotatable about an axis. The first and second housing portions of the housing are arranged on different sides of the vertical axis cross-section. The second housing portion has a central chamber and an outer chamber extending about the axis and the central chamber, the second fan wheel is received in the central chamber of the second housing portion and the rotatable housing has a first channel connecting the central chamber of the first housing portion and the outer chamber of the second housing portion and a second channel connecting the outer chamber of the first housing portion and the central chamber of the second housing portion, and the channels pass through the transverse plane of the casing.

Thus, in such a turbine, each impeller can fill the entire cross section of the central chamber in which it is located and drive it accordingly with high throughput. Since each impeller is in contact with only one fluid flow, the impellers need not accommodate the dual flow nature of the present machine, and low cost paddle wheels suitable for single flow machines can be used. Since the passages through which the counter-flowing fluids pass are located between the paddlewheels in the housing, they do not have to project beyond the circumference of the paddlewheels and can be accommodated on a small diameter so that the overall diameter of the housing only has to slightly exceed the paddlewheels. Furthermore, the thickness of the channel walls can be reduced, since the channels do not need to be rotated.

The first and second housing portions may be considered as separate parts or components that meet at the cross-section, they may be composed of parts that extend integrally in cross-section, which parts may be considered as part of the first housing portion or as part of the second housing portion. An advantage of the former alternative is that it allows the insertion of components, such as heat exchangers or pipes, between the cross-section of the first housing part and the cross-section of the second housing part, the pipes being used to bridge the distance between the two faces of the wall on which the turbine is mounted.

In order to connect first and second housing parts of identical construction, the two ends of the channel in the cross-section should be point-reflection mirror-symmetrical from the first channel to the second channel.

To avoid local airflow accumulation caused by the fan wheel drive, the first and second plurality of channels should be alternately distributed around the axis, optimally in the shape of a circular ring around the axis.

The first passage is optimally separated from the central chamber of the second portion or the outer chamber of the first portion by a partition extending towards a conical surface expanding outwardly from the second portion.

These baffles may be integrally connected in a single component.

According to an optimal solution, the casing comprises two identical internal parts opposite each other on both sides of one or more sections and comprises a partition separating the first channel from the central chamber of the second portion and a partition separating the second channel from the outer chamber of the second portion.

The two internal parts may further define a channel extending in cross section, which may receive a power supply cable for a motor driving the fan wheel.

Such a motor may be placed between the fan wheels.

It may be mounted on any of the internal components for convenience.

Furthermore, the housing comprises two identical outer parts in which the fan wheel engages. The arrangement of the housing parts in the inner and outer parts makes it possible in particular to provide the central chamber with a streamlined widening facing the housing cross section and to assemble the parts of the housing without undercuts, so that they can be manufactured with simple tools.

In order to conform to the shape of the central chamber, the fan wheel has a hub in the shape of a conical peg widening out towards the cross-section.

In order to drive the fluid flow in the axial direction, the fan wheel preferably has air blades projecting radially from the outer peripheral surface of its hub.

To minimize airflow noise, the number of air vanes in each fan wheel and the number of vents extending from the central chamber housing the fan wheel should be coprime.

The fan wheels may be mounted on a common shaft and mirror images of each other. Both side fan wheels can be driven by a single motor without a gearbox.

In order to reduce the production costs of the fan wheel, the same fan wheel may be used. But the fan wheel must be rotationally driven in the opposite direction. For this purpose, the fan wheel can be provided with a reversing device; but it is also possible to provide each fan wheel with a separate engine. The latter alternative is possible if the cross-sections of the first and second housing parts do not directly coincide.

In order to mount the heat exchanger between two overflows of the machine, the dimensions of the partition between the first and second channels are preferably greater than the dimensions of the channels (22,23) perpendicular to the partition, at least in one spatial direction.

The best field of application of the turbine of the present invention is in building ventilation. In particular, in such building ventilation systems, the turbine can be directly embedded in an opening of an external wall to control the air exchange between the space inside the building and the external environment; it may also be used as part of a central ventilation system to funnel airflow into multiple rooms of a building.

Further features and advantages of the invention will become apparent from the following description of exemplary embodiments, which refers to the accompanying drawings, in which:

FIG. 1 is an axial cross-sectional view of a turbine according to the present invention;

FIG. 2 is a radial section along plane B, C of FIG. 1;

FIG. 3 is a cross-section along plane A of FIG. 1;

FIG. 4 is a perspective view of the interior of the turbine housing;

FIG. 5 shows an alternative component along plane A;

FIG. 6 is a view of an alternative internal component;

FIG. 7 is another alternative portion along plane A;

FIG. 8 is a first modification of the cross-section similar to FIG. 1;

FIG. 9 is a second modification of the cross-section similar to FIG. 1;

FIG. 10 is a third modification of the cross-section similar to FIG. 1;

FIG. 11 is a perspective view of the internal components of the preferred embodiment;

FIG. 12 illustrates the inner portion of FIG. 11 from a different perspective;

FIG. 13 is a view of the two internal components of the stator mounted;

FIG. 14 shows the internal components of the fan wheel;

FIG. 15 is a fully assembled turbine;

FIG. 16 is a turbine with ducting to improve separation of the opposite direction air streams outside the machine.

Fig. 1 shows an axial section of a turbine according to the invention. The structure of the machine is largely mirror-symmetrical with respect to the section a. The base plate 1 extending in the section a faces the shaft 2, and the stator 4 of the motor 3 is arranged around the shaft 2. The rotor 5 of the electric motor 3 is mounted integrally in a first fan wheel 6, which first fan wheel 6 surrounds the stator 4. A shaft 8 mounted in the shaft 2 connects the first fan wheel 6 with the second fan wheel 7, the second fan wheel 7 being opposite thereto on the other side of the mirror image of the section a, so that the first fan wheel 6 and the second fan wheel 7 in the same direction about the shaft 9 can be driven by the motor 3. The first fan wheel 6 and the second fan wheel 7 here constitute an axial flow wheel with air blades 12 projecting radially from the circumferential surface 10 of its hub 11.

The first fan wheel 6 is accommodated in a central chamber 13, which central chamber 13 is enclosed by an annular peripheral wall 14. As shown, the diameter of the central chamber 13 may increase towards the section a; thus, the hub 11 is frustoconical, so that the air blades 12 rotate in an annular channel at the periphery of the central chamber 13, the diameter of which increases along the air inlet 15 to the section a.

The base plate 1 is flat as shown in fig. 1; but it may also protrude from the section a to increase the available installation space of the motor 3. Another idea is to mount the window for the base plate, which can be tightly inserted into the stator 4, so that it expands on both sides of the section a.

The outer chamber 16 extends around the central chamber 13 and beyond the partition 14. It is separated from the outside by an annular partition 17.

On the mirror-image opposite side of section a, the

partitions

18,19 define a boundary of a central chamber 20 housing the second fan wheel 7 and an outer chamber 21 surrounding the central chamber 20.

The base plate 1 is surrounded by

channels

22,23, one of which is visible in fig. 1. The

channels

22,23 alternate along the centre of the axis 9. The channels 22 are respectively connected to the central chamber 13 in section a, spaced from the outer chamber 21; instead, the passage 23 connects the central chamber 20 to the outer chamber 16.

By means of fig. 2, the distribution of the

channels

22,23 is shown visually. Fig. 2 shows the section B and C in fig. 1 through two parts of the turbine and the section along the plane a in fig. 3. The viewing directions of the two parts of fig. 2 are from the outside to the section a, respectively. The handedness of the air blades 12 and the direction of rotation of the first fan wheel 6 and the second fan wheel 7 indicated by the arrow 24 thus correspond to each other in mirror image in both parts. Part C passes through the

chambers

13, 16. The same channel 23 is located at the 12 o ' clock position in the chamber 16, which can also be seen in the section of fig. 1, where the channel 23 is located at the 4 o ' clock and 8 o ' clock positions. In the intermediate position, the view falls on the respective spacer portion 25. Between the partition 14 surrounding the central chamber 13 to the partitions 19 on the left and right sides of the section a, the partition portion 25 makes a continuous transition and hides the channel 22 behind the partitions 19. In the central chamber 13 is surrounded by the hub 11 and partly by the air blades 12 and the inlet of the channels 22. Between them, partition parts 26 can be seen, each connecting the bottom plate 1 with a partition 14.

In section B, the outer chamber 21 can be seen separating the channel 23 from the outer chamber 21 at the location of the 12,4 and 8 points on the partition portion 27, and each of which enters the channel 22. Within the inner chamber 20, the passages 23 are visible at 12 o ' clock, 4 o ' clock and 8 o ' clock and a partition portion 28 is visible therebetween, the partition portion 28 separating the passages 22 from the outer chamber 16.

In order to improve the outflow of air from the first fan wheel 6 and the second fan wheel 7, each guide vane can be mounted in the air flow in front of and/or behind the first fan wheel 6 and the second fan wheel 7, respectively. Fig. 2 illustrates a comb-like arrangement of the cross-section of a plurality of guide vanes 59 in the channel 23, which are inserted into the channel 23; corresponding measures can also be taken in the remaining space of the channel 23 and the channel 22.

Since the first fan wheel 6 and the second fan wheel 7 are mirror images of each other, air flows in opposite directions when they are driven in rotation in the same direction by the electric motor 3. Thus, air entering the central chamber 13 at the air inlet 15 is conveyed by the first fan wheel 6 via the channel 22 into the outer chamber 21, while the second fan wheel 7 pumps air from the central chamber 20 to the outer chamber 16.

Fig. 4 shows a perspective view of the inner part 30 of the turbine housing described above. The inner part comprises the base plate 1, partition portions 26 projecting from the edges of the base plate 1 towards the tapered surface of the first fan wheel 6, partition portions 28 projecting between the partition portions 26 towards the second fan wheel 7,

partition portions

25,27 defining the

passages

22,23 respectively outwardly, and partitions 29 interposed radially towards the axis 9 between the passages. As long as the

partition portions

26,28 adjoining the bottom plate 1 do not radially overlap the

outer partition portions

25,27, the inner portion 30 can be manufactured without undercuts by means of a simple forming tool movable in the direction of the axis 9.

Fig. 5 shows a section along plane a, and fig. 6 shows an inner portion 30 belonging to this section. The number of

channels

22,23 is increased compared to the inner part 30 of fig. 3. Their number and the number of fan blades of the first fan wheel 6 and the second fan wheel 7 are coprime, extending from the channels in its

chambers

13, 20.

Conversely, the number of

channels

22,23 can also be reduced to one in each direction, as shown in fig. 7.

Fig. 8 shows an axial section through a second embodiment of the turbine similar to fig. 1. The housing with the base plate 1, the

partitions

14,17,18,19 and the partition parts 25-28 connecting them are the same as in fig. 1. The second fan wheel 7 is not mirror-mounted here, but is identical to the first fan wheel 6; thus, the first fan wheel 6 and the second fan wheel 7 are not mounted on a common shaft, but are connected by a reversing gear 31 so that they rotate at the same speed but in opposite directions.

In the embodiment of fig. 9, the housing is again identical to the housing of fig. 1 and 8. Each first fan wheel 6 and second fan wheel 7 is equipped with its own electric motor 3. Likewise, the two

fan wheels

6,7 may be identical. By separate energization of the two motors 3, different throughputs in the two flow directions can be set in this case.

Fig. 10 shows a further improvement which is possible in all three embodiments of fig. 1, 8 and 9, but is easier to realize in fig. 8 and 9, since here the two

fan wheels

6,7 do not have a common shaft: the housing portions 49 constituting the inner chamber 13 and the outer chamber 16 and the housing portions 50 forming the

chambers

20,21 may be designed as separate parts, each part terminating at its base plate 1. The

housing portions

49,50 may be mounted with the adjoining base plate 1 to constitute the turbine of figure 9; here, a further housing part 51 is inserted between the base plates 1, wherein the

channels

22,23 each extend from one base plate 1 to the other.

The housing portion 51 is intended only to bridge the distance between the

housing portions

49,50 and it is intended to be inserted into a hole flush with the opposite surface of the building wall. In this case, as shown in fig. 7, it is feasible to minimize the number of

channels

22,23 and partitions 29 between them, so that the housing part 51 can be cut at minimum cost according to the required dimensions of the extruded profile. Alternatively, the housing portion 51 may be provided with two telescoping interlocking members so that the length of the housing portion 51 can be adapted by pulling or pushing the members.

In the embodiment of fig. 10, the housing part 51 is also used for a heat exchanger between the air flows circulating in opposite directions. For this purpose, the number of

channels

22,23 is large and their dimensions in the axial and radial directions are larger than in the circumferential direction for large-area heat exchange.

A more optimized way of adapting the principle shown in fig. 10 to the turbine shown in fig. 1, equipped with a single electric motor, is illustrated in dashed lines in the right half of fig. 10: the magnetic coupling 55 comprises two

magnetized clutches

56, 57. The magnetic coupling 55 comprises two magnetized

clutch discs

56,57 which, when brought sufficiently close to each other, can transmit torque from one to the other without the axes about which they are wound having to be precisely aligned. One clutch disc 56 is located on the shaft 8 of the motor 3 and the other clutch disc 57 is located on a shaft 58, the shaft 58 extending through the housing part 51. A second magnetic coupling, not shown in fig. 10, is provided between the other end of the shaft 58 and the second fan wheel 7. Thus, as in the case of fig. 1, the motor can be removed at the second fan wheel 7, and the motor 3 at the first fan wheel 6 can drive both the first fan wheel 6 and the second fan wheel 7. All three

housing parts

49,50,51, including their rotational axes, can be completely preassembled and connected to one another in the mounted position without causing different coaxiality or even rotation problems.

Fig. 11 illustrates an inner portion 32 of a turbine housing according to a preferred embodiment of the invention. The inner part comprises the base plate 1, a partition part 26 protruding from the edge of the base plate 1, a partition part 25 and a cylindrical outer wall ring 33. In the perspective view of fig. 11, section a extends along the lower edge of the outer wall ring 33. Distributed along the outer wall ring 33 are threaded channels 34, some of which have locking projections 35 beyond the section a, others having complementary receptacles with the locking projections 35. A sealing ring 36 extends along the upper edge of the outer wall ring 33. The edges of the

partition parts

25,26 facing away from the section a complement each other and form a circular edge 37, which may likewise be provided with a circumferential seal.

Fig. 12 and 13 show the inner part 32 with the stator 4 mounted on the base plate 1, in the perspective view of fig. 11 and with the base plate 1 facing the viewer. In the view of fig. 12, it can be seen that a seal is also formed along the lower edge of the outer wall ring 33; here it comprises springs 38 and recesses 39, each spring occupying half the circumference of the outer wall ring 33. A corresponding sealing ring 40 in the spring and groove extends around the base plate 1 and along the edge of the partition 29 extending in section a. One of the partitions 29 is widened to form half of a channel 41, in which channel 41 the power supply cables 42 of the motor 3 extend.

In the view of fig. 13, the inner part 32 and the inner part 43 of the second identical composition along section a are interconnected, by means of the locking projection 35 engaging the spring 38 of the inner part in the recess 39 of the other inner part.

In the next assembly step, ball bearings are inserted into the groove 44 and the second inner portion 43 of the stator 4, respectively, and the shaft 8 (not shown in fig. 13) is inserted into the ball bearings.

Fig. 14 shows the structure after the first fan wheel 6 and the second fan wheel 7 are connected at the end of the shaft 8.

In the assembly step shown in fig. 15, two identical

outer parts

45,46 are added to the

inner parts

32, 43. They each comprise an outer wall ring 47, which outer wall ring 47 is congruent with the outer wall ring 33 of the

inner part

32,43 and is plugged with its seal 36, which seal 36 forms, together with the outer wall ring 33, an

outer wall

17,19 surrounding the

outer chamber

16,21 and the

wall

14, 18. Which is plugged into the seals 36 of the

inner parts

32,43, separating the central chamber 13 and the outer chamber 21 from each other. Radial struts 60 connecting outer wall ring 47 with

walls

14 and 18, respectively, may be used to equalize air flow in

outer chambers

13,16, thereby minimizing flow losses and reinforcing

outer portions

45, 46.

The outer wall ring 47 is provided with a threaded passage 48, which in the assembled state of fig. 12 extends the threaded passage 34 of the

inner part

32,43, so that the

housing parts

32,43,45,46 are fixed and connected together, if necessary also to the base, by means of screws inserted into the threaded

passages

34, 48.

The tubular baffles 14,18 extend axially beyond the outer wall ring 47 so that, if desired, conduits can be connected to them to further partially separate the inlet and outlet ports.

An example of such a conduit 52 is partially illustrated in fig. 16. In the first portion 53 of the duct 52, the

chambers

13,16 extend axially, for example, as long as necessary, when the arrangement shown in fig. 15 is inserted from a first side into a wall opening, to reach the opposite side; above the second hypothetical wall opening projection 54, the lumen 13 continues to extend axially, while the chamber 16 merges into a radially oriented tube segment.

Reference mark

1 inside the bottom plate 32

2 axle 33 outer wall ring

3 motor 34 screw channel

4 stator 35 lock projection

5 rotor 36 sealing ring

6 first fan wheel 37 edge

7 second fan wheel 38 spring

8 groove of rotating shaft 39

9-axis 40 sealing ring

10 peripheral surface 41 pipeline

11 hub 42 supply cable

12 inside blade 43

13 central chamber 44 recess

14 outside of the partition 45

15 outside of the air inlet 46

16 outer chamber 47 outer wall ring

17 partition 48 threaded passage

18 baffle 49 shell section

19 baffle 50 housing portion

20 center chamber 51 housing portion

21 outer chamber 52 conduit

22 channel 53 section

23 channel 54 section

24 rotation direction 55 magnetic coupling

25 spacer portion 56 clutch plate

26 spacer portion 57 clutch plate

27 spacer portion 58 axle

28 spacer portion 59 turbine blade

29 baffle plate

30 inner 60 struts.

31 reverse gear

Claims

1. A turbine with a housing, characterised in that the housing of the turbine comprises a first housing part having a central chamber (13) and an outer chamber (16) extending around the central chamber (13), and a first fan wheel (6) located in the central chamber (13) and driven in rotation about an axis (9), wherein the first and second housing parts are located on different sides of a cross-section (a) perpendicular to the axis (9), wherein a second fan wheel (7) driven in rotation about the axis (9) is contained in a central chamber (20) of the second housing part, and an outer chamber (21) extending around the axis (9) and the central chamber (20), wherein the housing comprises a first passage (22) and a second passage (23), the first passage (22) connecting the central chamber (13) of the first housing part to the second housing part -a partial outer chamber (21), -a second channel (23) connecting the outer chamber (16) of the first housing part and the central chamber (20) of the second housing part, wherein the first channel (22) and the second channel (23) pass through a cross-section (a) of the housing, wherein the first fan wheel (6) and the second fan wheel (7) are mounted on a common shaft (8) and are mirror inverted, and wherein the first channel (22) is optimally separated from the central chamber (20) of the second housing part and/or the outer chamber (16) of the first housing part by a partition extending towards a conical surface expanding outwards from the second housing part.

2. The turbine according to claim 1, characterized in that the axis (9) in the section plane (a) should have point-reflection mirror symmetry at both ends from the first channel (22) to the second channel (23).

3. The turbomachine of claim 1, wherein a plurality of said first channels (22) and a plurality of said second channels (23) are alternately rounded around said axis (9).

4. The turbomachine of claim 1, wherein the casing comprises two identical inner parts (32,43) opposite each other on both sides of the section (a) and comprises a partition separating the second channel (23) from the central chamber (13) of the first casing part and a partition separating the first channel (22) from the outer chamber (16) of the second casing part.

5. Turbomachine according to claim 4, characterised in that at least one electric machine (3) for driving the first fan wheel (6) and the second fan wheel (7) and located between the first fan wheel (6) and the second fan wheel (7) is accommodated.

6. The turbine according to claim 5, characterized by an electric motor (3) mounted on one of the internal components.

7. Turbomachine according to claim 1, characterised in that the housing comprises two identical outer parts (45,46) in which the first fan wheel (6) and the second fan wheel (7) engage.

8. The turbomachine according to claim 1, characterised in that said first fan wheel (6) and said second fan wheel (7) can have a hub (11) in the shape of a conical pile widening towards said section (a).

9. Turbomachine according to claim 8, characterised in that the blades (12) of the first fan wheel (6) and the second fan wheel (7) project radially from the outer peripheral surface (10) of the hub (11).

10. Turbomachine according to claim 1, characterised in that the number of blades (12) of each first fan wheel (6) and of the second fan wheel (7) and the number of first channels (22) and of second channels (23) projecting from the central chamber housing the first fan wheel (6) and the second fan wheel (7) should be coprime.

11. The turbomachine of claim 1, wherein a diameter of a partition between the central chamber and the outer chambers of the first and second casing portions increases towards the cross section (a).

12. Turbomachine according to claim 1, characterised in that the first fan wheel (6) and the second fan wheel (7) have the same structure and are driven in rotation in opposite directions.

13. The turbine according to claim 1, characterised in that the dimension of the partition separating the first channel (22) from the second channel (23) is, at least in one spatial direction, greater than the dimension of the first channel (22) and the second channel (23) perpendicular to the partition.

14. A building ventilation system comprising a turbine according to claim 1.