EP3542066B1 - Double-flow turbomachine - Google Patents

Description

The present invention relates to a flow machine for simultaneously driving oppositely directed fluid flows, in particular air flows. Such flow machines are particularly suitable for avoiding a pressure difference with the environment when ventilating a room that does not communicate with the environment or only communicates with it via narrow passages.

Out of EN 10 2008 031 084 A double-flow fan is known in which a fan wheel has two ring-shaped arrangements of air blades that differ in their handedness, so that when the fan wheel rotates, they drive flows in opposite directions. One problem with this fan is that the air flows cannot be kept completely separate from each other.

Also the US 3 421 428 A reveals such a double-flow fan.

A double-flow fan, which allows a separation of the opposing air flows, is made of EN 10 2014 118 210 A1 This fan has a special fan wheel with fluid inlets on two opposite Front sides; the opposing air flows are guided past each other via the fan wheel's internal channels and then released again via fluid outlets on the circumference of the fan wheel. The space required by the internal channels means that the fluid inlets can only fill about half of the front sides of the fan wheel. The fan's throughput is therefore considerably smaller than that of a single-flow fan with the same diameter. The wall thickness of the channels must be large enough to withstand the centrifugal forces that occur during operation. The throughput cannot therefore be increased by increasing the speed without simultaneously reducing the free cross-section of the channels and increasing the moment of inertia of the fan wheel.

An object of the present invention is to provide a double-flow turbomachine which is inexpensive to manufacture and achieves a high throughput for a given diameter and a given speed.

The object is achieved in that, in a turbomachine with a housing that has a first housing section with a central chamber and an outer chamber extending around the central chamber, and a first fan wheel that is accommodated in the central chamber of the first housing section of the housing and can be driven in rotation about an axis, the first housing section and a second housing section of the housing are arranged on different sides of a cutting plane perpendicular to the axis, the second housing section has a central chamber in which a second fan wheel that can be driven in rotation about the axis is arranged, and an outer chamber extending around the axis and the central chamber, and that the housing has a first passage that connects the central chamber of the first housing section to the outer chamber of the second housing section, and a second passage that connects the outer chamber of the first housing section to the central chamber of the second housing section, and that the passages cross the cutting plane of the housing. In such a turbomachine, each impeller can thus fill the entire cross section of its central chamber and accordingly convey with a high throughput. Since each impeller only has a fluid flow, a special adaptation of the impeller to the double-flow system of the machine is not necessary and inexpensive impellers that are also used for single-flow machines can be used. Since the passages by means of which the counter-rotating fluid flows are guided past each other are arranged between the impellers in the housing, they do not have to protrude beyond the circumference of the impellers and can therefore be accommodated in a small diameter so that the total diameter of the housing only has to exceed that of the impellers slightly. In addition, since the passages do not have to rotate, the wall thickness of the passages can be kept low.

The first and second housing sections can be designed as individual components or assemblies that meet at the cutting plane, or they can be formed by components that extend in one piece across the cutting plane and belong partly to the first and partly to the second housing section. The first alternative has the advantage that it allows additional housing parts to be inserted between the cutting plane of the first housing part and that of the second, such as a pipe for bridging the distance between two surfaces of a wall in which the turbomachine is to be mounted, or a heat exchanger.

In order to be able to connect identical first and second housing components to each other, the passages in the cutting plane should be arranged in such a way that a point reflection on the axis maps the first passage onto the second passage.

To avoid local accumulation of fluid driven by the fan wheels, several first passes and several second passes should be distributed alternately around the axis, preferably arranged in a circle around the axis.

According to the invention, a first passage from the central chamber of the second section and/or from the outer chamber of the first section separated by a wall that extends along a conical shell that widens towards the second section.

These walls may be integrally connected in a single component. According to a preferred variant, the housing comprises two identical inner parts, which are opposite one another on either side of the cutting plane or planes, one of which comprises walls separating a first passage from the central chamber of the second section and walls separating a second passage from the outer chamber of the second section.

These two internal parts can further define a channel extending in the cutting plane, which can accommodate a supply cable for a motor driving the fan wheels.

Such a motor can be placed between the fan wheels.

It can be conveniently mounted on one of the internal parts.

Furthermore, the housing can comprise two identical outer parts into which the fan wheels engage. The division of a housing section into an inner and outer part makes it possible in particular to provide the central chamber with a flow-optimized widening facing the cutting plane of the housing section and at the same time to keep the components from which the housing is assembled free of undercuts so that they can be formed with simple tools.

To match the shape of the central chamber, the fan wheels can have a hub in the form of a truncated cone that widens towards the cutting plane.

In order to drive the fluid flows in the axial direction, the fan wheels preferably have air blades that protrude radially from a circumferential surface of their hubs.

To minimize airflow noise, the number of air blades on each impeller and the number of passages emanating from the central chamber containing the impeller should be coprime.

According to the invention, the fan wheels are mounted on a common shaft and are shaped like a mirror image of each other. Then both can be driven by a single motor without a gearbox.

In order to reduce the effort involved in manufacturing the fan wheels, identical fan wheels can be used. However, these must then be driven in opposite directions. A reversing gear can be provided for this purpose; however, each fan wheel can also be assigned its own motor. The latter alternative can be particularly useful if the cutting planes of the first and second housing sections do not coincide directly.

In order to create a heat exchanger between the two flows of the machine, the dimension of a wall separating a first passage from a second passage should preferably be larger in at least one spatial direction than the dimensions of the passages perpendicular to this wall.

A preferred area of application of the flow machine according to the invention is building ventilation systems. In such a building ventilation system, the flow machine can in particular be installed directly in an opening in an external wall in order to control the air exchange between a room inside the building and the environment; however, it can also be part of a central ventilation system where air flows from and to several rooms in the building converge.

Fig. 1

einen axialen Schnitt durch eine erfindungsgemäße Strömungsmaschine;

Fig. 2

radiale Schnitte entlang der Ebenen B, C der Fig. 1;

Fig. 3

einen Schnitt entlang der Ebene A der Fig. 1;

Fig. 4

eine perspektivische Ansicht eines Innenteils des Gehäuses der Strömungsmaschine;

Fig. 5

einen alternativen Schnitt entlang der Ebene A;

Fig. 6

eine Ansicht eines alternativen Innenteils; Fig. 7 einen weiteren alternativen Schnitt entlang der Ebene A;

Fig. 8

einen zu Fig. 1 analogen Schnitt gemäß einer ersten Abwandlung;

Fig. 9

einen zu Fig. 1 analogen Schnitt gemäß einer zweiten Abwandlung;

Fig. 10

einen zu Fig. 1 analogen Schnitt gemäß einer dritten Abwandlung;

Fig. 11

eine perspektivische Ansicht eines Innenteils gemäß einer bevorzugten Ausgestaltung;

Fig. 12

das Innenteil der Fig. 11 aus anderer Perspektive;

Fig. 13

zwei Innenteile mit darauf montiertem Stator;

Fig. 14

die Innenteile mit angefügten Lüfterrädern;

Fig. 15

die vollständig montierte Strömungsmaschine und

Fig. 16

eine Strömungsmaschine, ergänzt durch eine Rohrleitung zur verbesserten Trennung der gegenläufigen Luftströmungen außerhalb der Maschine.

Further features and advantages of the invention will become apparent from the following description of embodiments with reference to the accompanying figures. They show:

Fig.1

an axial section through a turbomachine according to the invention;

Fig.2

radial sections along planes B, C of the Fig.1 ;

Fig.3

a section along plane A of the Fig.1 ;

Fig.4

a perspective view of an inner part of the housing of the turbomachine;

Fig.5

an alternative section along plane A;

Fig.6

a view of an alternative interior part; Fig.7 another alternative section along plane A;

Fig.8

one to Fig.1 analogous cut according to a first variation;

Fig.9

one to Fig.1 analogous cut according to a second variation;

Fig.10

one to Fig.1 analogous cut according to a third variation;

Fig. 11

a perspective view of an inner part according to a preferred embodiment;

Fig. 12

the inner part of the Fig. 11 from a different perspective;

Fig. 13

two inner parts with stator mounted on them;

Fig. 14

the internal parts with attached fan wheels;

Fig. 15

the fully assembled turbomachine and

Fig. 16

a flow machine, supplemented by a pipe for improved separation of the opposing air flows outside the machine.

Fig.1 shows an axial section through a turbomachine according to the invention. The structure of the machine is largely mirror-symmetrical with respect to a cutting plane A. A cylindrical shaft 2 protrudes from a base plate 1 extending in the cutting plane A, around which a stator 4 of an electric motor 3 is arranged. A rotor 5 of the electric motor 3 is integrated in a fan wheel 6 that surrounds the stator 4. A shaft 8 mounted in the shaft 2 connects the fan wheel 6 to a fan wheel 7 that is opposite it in mirror image on the other side of the cutting plane A, so that both fan wheels 6, 7 can be driven in rotation in the same direction about an axis 9 by the electric motor 3. The fan wheels 6, 7 are designed here as axial fan wheels, with air blades 12 projecting radially from a peripheral surface 10 of their hub 11.

The fan wheel 6 is housed in a central chamber 13 which is delimited by an annular peripheral wall 14. The diameter of the central chamber 13 can, as shown, increase towards the section plane A; accordingly, the hub 11 can also be frustoconical, so that the air blades 12 rotate in an annular channel on the periphery of the central chamber 13, the diameter of which increases from an intake opening 15 towards the section plane A.

The base plate 1 is in Fig.1 shown flat; however, it can also be cup-shaped and protrude from the cutting plane A in order to increase the available installation space for the electric motor 3. It is also conceivable to provide the base plate with a window into which the stator 4 can be tightly inserted in order to expand on both sides of the cutting plane A. An outer chamber 16 extends beyond the wall 14 around the central chamber 13. It is delimited on the outside by an annular wall 17.

In mirror image to this, on the opposite side of the cutting plane A, walls 18, 19 delimit a central chamber 20 accommodating the fan wheel 7 and an outer chamber 21 surrounding the central chamber 20.

The base plate 1 is surrounded by passages 22, 23, one of which is in Fig.1 can be seen in section. The passages 22, 23 are distributed alternately along a circle centered around the axis 9. The passages 22 each connect the central chamber 13 with the outer chamber 21 across the cutting plane A; conversely, the passages 23 connect the central chamber 20 with the outer chamber 16.

The distribution of passages 22, 23 is easier to imagine by looking at the Fig.2 , which show two sections through the turbomachine along the planes B and C of the Fig.1 shows, and the Fig.3 , which shows a section along the plane marked A. The viewing direction of the two sections of Fig.2 is from the outside towards the section plane A; therefore, the handedness of the air blades 12 and the direction of rotation of the fan wheel 6 or 7, indicated by an arrow 24, appear mirror images of each other in the two sections. Section C runs through the chambers 13, 16. In chamber 16, at the 12 o'clock position, there is the same passage 23 that is also shown in the section of the Fig.1 can be seen, further passages 23 are located at 4 o'clock and 8 o'clock positions. At the positions in between, the view falls on a wall section 25 which creates a continuous transition between the wall 14 surrounding the central chamber 13 to the left of the cutting plane A and the wall 19 to the right of the cutting plane A and behind which a passage 22 is hidden. In the central chamber 13, around the hub 11 and partially covered by the air blades 12, inlets of the passages 22 and, between them, wall sections 26 can be seen, each of which connects the base plate 1 to the wall 14.

In section B, in the outer chamber 21, one looks at the 12, 4 and 8 o'clock positions onto wall sections 27 which separate the passages 23 from the outer chamber 21, and in between into the passages 22; within the inner chamber 20, one looks at the 12, 4 and 8 o'clock positions onto the passages 23, and in between into the wall sections 28 which separate the passages 22 from the outer chamber 16.

In order to improve the outflow of air from the fan wheels 6, 7, guide vanes can be arranged in the air flow in front of and/or behind the fan wheels 6, 7. Fig.2 shows, by way of example, in a passage 23 a comb-like arrangement of several guide vanes 59 which is inserted into the passage 23; corresponding arrangements could also be provided in the remaining passages 23 and the passages 22.

Since the fan wheels 6, 7 are mirror images of each other, they drive air flows in opposite directions when they are rotated in the same direction by the electric motor 3. Air that enters the central chamber 13 at the intake opening 15 is conveyed by the fan wheel 6 via the passages 22 into the outer chamber 21, while at the same time the fan wheel 7 pumps air from the central chamber 20 to the outer chamber 16.

Fig.4 shows an inner part 30 of the housing of the turbomachine described above in perspective view. The inner part comprises the base plate 1, the wall sections 26 projecting from the edge of the base plate 1 on a conical surface towards the fan wheel 6, the wall sections 28 projecting between the wall sections 26 towards the fan wheel 7, the wall sections 25, 27 delimiting the passages 22, 23 on the outside, and partition walls 29 oriented radially to the axis 9 between the passages. As long as the wall sections 26, 28 adjacent to the base plate 1 do not radially overlap with the outer wall sections 25, 27, the inner part 30 can be manufactured without undercuts using simple molds that can be moved in the direction of the axis 9.

Fig.5 shows a section along plane A and Fig.6 an inner part 30 belonging to this section. The number of passages 22, 23 is compared to the inner part 30 of the Fig.3 It is in each case coprime with the number of air blades on the fan wheel 6 or 7, from whose chambers 13, 20 the passages originate.

Conversely, the number of passages 22, 23 can also be reduced to one in each direction, as in Fig.7 shown.

Fig.8 shows a non-inventive embodiment and a Fig.1 analogous axial section through a second design of the turbomachine. The housing with base plate 1, walls 14, 17, 18, 19 and the connecting wall sections 25-28 is the same as that of the Fig.1 identical. The fan wheel 7 is not a mirror image of the fan wheel 6, but is identical in construction; therefore, the fan wheels 6, 7 are not mounted on a common shaft, but are coupled to one another via a reversing gear 31, so that they rotate at the same speed but in opposite directions.

In the non-inventive embodiment of the Fig.9 the housing is again identical to that of the Fig.1 and 8th . Each fan wheel 6, 7 is assigned its own electric motor 3. Here too, both fan wheels 6, 7 can be of the same construction. By supplying both motors 3 with electricity separately, different throughputs can be set in the two conveying directions.

Fig.10 shows a further development not according to the invention, which is indeed applicable to all three embodiments of the Fig.1 , 8 and 9 possible, but for those of Fig. 8 and 9 is particularly inexpensive to implement, since the two fan wheels 6, 7 do not have a common shaft: A housing section 49, which forms the inner chamber 13 and the outer chamber 16, and a housing section 50, which forms the chambers 20, 21, are designed as individual components, each of which ends at its base plate 1. The housing sections 49, 50 could be mounted to one another with base plates 1 abutting one another in order to form the turbomachine of the Fig.9 to form; here, a further housing section 51 is inserted between the base plates 1, in which the passages 22, 23 continue from one base plate 1 to the other.

The housing section 51 may only serve the purpose of bridging the distance between the housing sections 49, 50 which results when they are inserted into a hole in a building wall flush with the opposing surfaces of the building wall. In this case it may be expedient to increase the number of passages 22, 23 and walls 29 between them as in Fig.7 shown so that the housing section 51 can be cut to the required length from an extruded profile with little effort, or two telescopically interlocking components can be provided to create a housing section 51, the length of which can be adapted to requirements by pulling the components apart or pushing them together.

In the design of the Fig.10 the housing section 51 also serves as a heat exchanger between the air flows circulating in opposite directions. For this purpose, the passages 22, 23 are numerous and their dimensions in the axial and radial directions are larger than in the circumferential direction in order to enable heat exchange over a large area.

An advantageous way to implement the principle of Fig.10 also to a turbomachine with only one engine according to Fig.1 to transfer is in the right half of the Fig.10 shown in dashed lines: a magnetic coupling 55 comprises two magnetic clutch discs 56, 57 which, when they are positioned close enough to each other, can transmit torque from one to the other without the axes around which they rotate having to be exactly aligned. One clutch disc 56 is located on the shaft 8 of the motor 3, the other clutch disc 57 on a shaft 58 which extends through the housing section 51. A second, in the Fig.10 A magnetic coupling (not shown) is provided between the opposite end of the shaft 58 and the fan wheel 7. As in the case of the Fig.1 a motor on the side of the fan wheel 7 is not required, and the motor 3 on the side of the fan wheel 6 can drive both fan wheels 6, 7. All three housing sections 49, 50, 51, including their rotating shafts, can be completely pre-assembled and only connected to one another at the installation site, without imperfect coaxiality of the shafts leading to concentricity problems.

Fig. 11 shows an inner part 32 of the housing of the turbomachine according to a preferred embodiment of the invention. The inner part comprises the base plate 1, the wall sections 26 protruding from the edge of the base plate 1, the wall sections 25 and a cylindrical outer wall ring 33. In the Perspective of Fig. 11 the cutting plane A runs along a lower edge of the outer wall ring 33. Screw channels 34 are distributed along the outer wall ring 33, some of which have a locking projection 35 that projects beyond the cutting plane A and the others have a receptacle that is complementary to the locking projection 35. A seal 36 extends along an upper edge of the outer wall ring 33. The edges of the wall sections 25, 26 facing away from the cutting plane A complement each other to form a circular edge 37, which can also be provided with a circumferential seal.

Fig. 12 and 13 show the inner part 32 with a stator 4 mounted on the base plate 1, once in the perspective of the Fig. 11 and once with the base plate 1 facing the viewer. In the view of the 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 a tongue 38 and a groove 39, each of which takes up half of the circumference of the outer wall ring 33. A corresponding seal 40 divided into tongue and groove extends around the base plate 1 and along edges of the partition walls 29 running in the cutting plane A. One of the partition walls 29 is widened to form half of a channel 41 in which a supply cable 42 of the motor 3 runs.

In the view of the Fig. 13 the inner part 32 and a second, identical inner part 43 are connected to one another along the plane A in that the locking projections 35 and the spring 38 of one inner part engage in the recesses or the groove 39 of the other inner part.

In a next assembly step, ball bearings are inserted into a recess 44 of the stator 4 or onto the second inner part 43, and the (in Fig. 13 Shaft 8 (not shown) is inserted into the ball bearings.

Fig. 14 shows the structure after attaching the fan wheels 6, 7 to the ends of the shaft 8.

In Fig. 15 In the assembly step shown, two identical outer parts 45, 46 are added to the inner parts 32, 43. These each comprise a The outer wall ring 47, which is congruent with the outer wall rings 33 of the inner parts 32, 43 and plug-connected to their seals 36, forms the outer walls 17, 19 around the outer chambers 16, 21 together with the outer wall rings 33, as well as the walls 14, 18, which, plug-connected to the seals 36 of the inner parts 32, 43, separate the central and outer chambers 13, 16 and 20, 21 from each other. Radial struts 60, which connect the outer wall rings 47 to the walls 14 and 18, can serve both to even out the air flow in the outer chambers 13, 16 and thus to minimize flow losses and to stiffen the outer parts 45, 46. The outer wall rings 47 are provided with screw channels 48, which, when the Fig. 12 extend the screw channels 34 of the inner parts 32, 43 so that the housing parts 32, 43, 45, 46 can be firmly connected to one another and, if necessary, also fastened to a base by means of screws inserted into the screw channels 34, 48.

The tubular walls 14, 18 extend axially beyond the outer wall rings 47 so that, if necessary, a pipe can be attached to them in order to increase the spatial separation of the air inlet and outlet.

An example of such a pipeline 52 is shown - partially cut open - in Fig. 16 In a first section 53 of the pipe 52, the chambers 13, 16 are axially extended, e.g. as far as necessary, in order to Fig. 15 shown arrangement has been inserted into a wall opening from a first side to reach the opposite side; in a second section 54 projecting beyond this imaginary wall opening, the inner chamber 13 continues to extend axially, whereas the chamber 16 merges into a radially oriented pipe section.

Reference symbols

1 Base plate 32 inner part 2 shaft 33 Outer wall ring 3 Electric motor 34 Screw channel 4 stator 35 Locking projection 5 rotor 36 poetry 6 Fan wheel 37 Edge 7 Fan wheel 38 Feather 8th Wave 39 Groove 9 axis 40 poetry 10 Circumferential area 41 channel 11 hub 42 Supply cable 12 Air scoop 43 inner part 13 central chamber 44 Recess 14 Wall 45 Outer part 15 Intake opening 46 Outer part 16 outer chamber 47 Outer wall ring 17 Wall 48 Screw channel 18 Wall 49 Housing section 19 Wall 50 Housing section 20 central chamber 51 Housing section 21 outer chamber 52 Pipeline 22 Passage 53 Section 23 Passage 54 Section 24 Direction of rotation 55 Magnetic coupling 25 Wall section 56 Clutch disc 26 Wall section 57 Clutch disc 27 Wall section 58 Wave 28 Wall section 59 vane 29 partition wall 60 strut 30 inner part 31 Reversing gear

Claims (14)

1. A turbomachine with a housing having a first housing section (14, 17; 32, 45; 49) with a central chamber (13) and an outer chamber (16) extending around the central chamber (13), and a first fan wheel (6) which is accommodated in the central chamber (13) of the first housing section (14, 17; 32, 45) of the housing and can be driven in rotation about an axis (9), wherein the first housing section (14, 17; 32, 45; 49) and a second housing section (18, 19; 43, 46; 50) of the housing are arranged on different sides of a sectional plane (A) perpendicular to the axis (9), wherein the second housing section (18, 19; 43, 46; 50) has a central chamber (20) in which is arranged a second fan wheel (7) which can be driven in rotation about the axis (9), and an outer chamber (21) extending around the axis (9) and the central chamber (20), wherein the housing has a first passage (22) which connects the central chamber (13) of the first housing section (14, 17; 32, 45; 49) with the outer chamber (21) of the second housing section (18, 19; 43, 46) and a second passage (23) which connects the outer chamber (16) of the first housing section (14, 17; 32, 45; 49) with the central chamber (20) of the second housing section (18, 19; 43, 46), wherein the passages (22, 23) cross the sectional plane (A) of the housing, and wherein the fan wheels (6, 7) are mounted on a common shaft (8) and are shaped as a mirror image of one another, characterized in that the first passage (22) is separated from the central chamber (20) of the second housing section (18, 19; 43, 46) and/or from the outer chamber (16) of the first housing section (14, 17; 32, 45) by a wall (25, 28) which is located on a conical surface which extends to the second housing section (18, 19; 43, 46).
2. The turbomachine according to claim 1, characterized in that a point reflection of the sectional plane (A) on the axis (9) maps the first passage (22) onto the second passage (23).
3. The turbomachine according to claim 1 or 2, characterized in that a plurality of first passages (22) and a plurality of second passages (23) are arranged alternately on a circle around the axis (9).
4. The turbomachine according to any one of the preceding claims, characterized in that the housing comprises two identical inner parts (32, 43) which are situated opposite one another on either side of the sectional plane (A), one of which comprises walls (25) which separate a second passage (23) from the central chamber (13) of the first housing section and walls (26) which separate a first passage (22) from the outer chamber (16) of the first housing section.
5. The turbomachine according to any one of the preceding claims, characterized in that at least one motor (3) for driving the fan wheels (6, 7) is accommodated between the fan wheels (6, 7).
6. The turbomachine according to claim 4 and claim 5, characterized in that the motor (3) is mounted on one of the inner parts (32).
7. The turbomachine according to any one of the preceding claims, characterized in that the housing comprises two identical outer parts (45, 46) into which the fan wheels (6, 7) engage.
8. The turbomachine according to any one of the preceding claims, characterized in that the fan wheels (6, 7) have a hub (11) in the form of a truncated cone that is widened toward the sectional plane (A).
9. The turbomachine according to any one of the preceding claims, characterized in that air blades (12) of the fan wheels (6, 7) protrude radially from a circumferential surface (10) of the hubs (11).
10. The turbomachine according to any one of the preceding claims, characterized in that the number of air blades (12) of each fan wheel (6, 7) and the number of passages (22, 23) extending from the central chamber (13, 20) accommodating the fan wheel (6, 7) are coprime.
11. The turbomachine according to any one of the preceding claims, characterized in that a wall (17, 19) between the central chamber (13, 20) and the outer chamber (16, 21) of a housing section has a diameter which increases toward the sectional plane (A).
12. The turbomachine according to any one of the preceding claims, characterized in that the fan wheels (6, 7) are identical in construction and driven in opposite directions of rotation.
13. The turbomachine according to any one of the preceding claims, characterized in that the dimension of a wall (29) separating a first passage (22) from a second passage (23) is greater in at least one spatial direction than the dimensions of the passages (22, 23) perpendicular to the wall (29).
14. A building ventilation system, characterized by a turbomachine according to any one of the preceding claims.

Images