EP2815130B1 - Diffusor, ventilator having such a diffusor, and device having such ventilators - Google Patents

Description

The invention relates to a diffuser according to the preamble of claim 1, a ventilator according to the preamble of claim 13 or 14 and a device with such ventilators according to claim 16.

12 shows a state-of-the-art device ( DE 35 15 441 ), which is provided with a housing. On its top are fans mounted on heat exchangers. The fans blow the air freely so that all dynamic energy is lost at the fan outlet.

Outlet diffusers are used to reduce the considerable flow losses at the outlet of pipelines, fans and the like ( DE 20 2011 004 708 U1 , US2011217164 A1 , CN201723504U , FR 27 28 028 ). However, on devices such as table coolers, there is only limited space available in the radial direction. Since the outlet diffusors have a circular cross-section, the fans with the outlet diffusors cannot be lined up close together. However, this is often necessary with such devices, in which case the fans must also be arranged in several rows close to one another. A considerable amount of space is thus lost on a device with several fans. Local dead water areas then also form between the diffusers, which lead to increasing losses.

It is known ( GB 788 581A ), to arrange two fans next to each other, each located in the area of snail-shaped housings. A diffuser connects to each of the snail-shaped housings, the cross-section of which steadily increases in the flow direction of the air. The transitions between the sides of the walls of the diffusers are curved in accordance with the curved course of the side walls.

A diffuser is also known ( U.S. 2,209,121 A ), which has a plurality of walls surrounding one another at a distance, between which passages are formed. The outlet ends of the walls are at different heights to increase the outflow area of the diffuser.

Finally, a diffuser is known ( U.S. 2,750,865 A ) which has at least one wall which encloses an inlet with a circular cross-section and changes over the height of the wall of the diffuser into an angular cross-section at the outlet of the diffuser, the diffuser having at least one further wall which is surrounded by the wall at a distance . At the inlet, the further wall has a round, preferably circular cross section, which continuously transitions into an angular cross section over the height of the further wall.

The invention is based on the object of designing the diffuser of the generic type, the fan of the generic type and the device in such a way that the space on the devices can be optimally utilized without a structurally complex design being necessary for this.

This object is achieved according to the invention with the generic diffuser with the characterizing features of claim 1, with the generic fan according to the invention with the characterizing features of claim 13 or 14 and with the device with the features of claim 16.

In the case of the diffuser according to the invention, the transitions between the sides of the wall have a twist in the height direction, which follows the swirl of the flow of air through the diffuser. The transitions thus do not run along a straight line in the vertical direction of the diffuser wall, but are correspondingly curved. The transition areas are designed in such a way that they follow the flow direction of the air in the diffuser or the swirl of the flow behind the impeller of the fan. This results in only minimal losses in the area of these transitions. The diffuser wall itself has an angular outline at least at the outlet, where an angular outline is also to be understood as meaning that the transition between the sides of the diffuser wall can be rounded. The angular design makes it possible to place several diffusers next to each other with only a small distance, so that in devices where there is only limited space and several diffusers are required, these can be arranged directly next to each other in one or more rows. Since the diffuser has the round cross-section at the inlet, the diffuser according to the invention can be connected to conventional fans whose connection area is generally round or circular in shape. The diffuser according to the invention can therefore also be attached to existing fans.

The outlet of the diffuser wall advantageously has a square outline, so that adjacent diffusers can be positioned with their respective outlined sides either abutting or next to and behind one another with only a very small distance. As a result, the area is optimally used to delay the flow rate.

Depending on the design of the surface of the respective device, the diffuser walls can have a triangular, square, hexagonal or other polygonal outline, at least at the outlet. The quadrangular outline is advantageous here if the mounting surface has a corresponding quadrangular outline.

An optimal design results when the diffuser wall has an angular outline over most of its height. Diffusors lying next to and/or behind one another can then be arranged with the smallest possible spacing or also abutting one another. This means that the corresponding device surface can be used almost completely.

The sides of the angular diffuser wall are advantageously continuously curved into each other, resulting in optimal flow conditions.

In a preferred embodiment, the cross section of the diffuser increases in the flow direction, which is advantageous for reducing the flow velocity. It is advantageous if the cross section of the diffuser first decreases and then increases from the inlet end. As a result, the flow can be decelerated with only small losses in the increasing cross-sectional area, resulting in a high diffuser efficiency.

The diffuser is advantageously provided with at least one further wall, which is surrounded by the diffuser wall at a distance. This further wall results in optimal flow conditions.

In this case, the walls of the diffuser can have the same height, but they can also optionally be of different heights. It is therefore very easy to achieve the desired flow conditions by designing the diffuser walls appropriately.

The other wall of the diffuser is advantageously designed similarly to the outer diffuser wall. Accordingly, the additional wall advantageously has an angular cross-section, at least at the outlet.

The sides of the further diffuser wall advantageously merge into one another in a continuously curved manner.

The further diffuser wall has a round, preferably circular outline at the inlet, which continuously merges into the angular cross-section over the height of the further diffuser wall. Thus, the flow conditions are significantly better even when using at least one additional diffuser wall.

The transitions between the sides of the further angular diffuser wall have a twist or twist in the vertical direction.

The transitions between the sides of the wall advantageously have a twist satisfying the relationship θ x L/D, where the angle θ is measured between two radials, one of which is a radial through the intersection between the transition and the free edge at the inlet of the wall, while the other radial runs from the axis of the inlet to the corner area of the wall in the outlet, from which the transition extends, in each case seen in the axial direction of the diffuser, and that the torsion is in a range between about 50 ° and about 100°. The flow conditions can be optimally adapted to the respective application by selecting the angle between the two radials and the ratio between the diameter of the fan and the axial length of the diffuser. The relationship between this angle and the dimensional ratio applies not only to the diffuser outer wall, but also to any further diffuser walls that may be provided. The value can be the same for all walls, but can also differ from wall to wall.

It is advantageous if the ratio of the inlet cross section to the outlet cross section of the diffuser is in a range of <approximately 5, advantageously between approximately 1.2 and approximately 3. The efficiency of the diffuser can be excellently adjusted to the application by selecting the inlet and outlet cross-sections in relation to each other.

The outlet ends of the two walls can be at different heights to increase the outflow area of the diffuser, with the wall surrounding the further wall to form a passage. By choosing the appropriate height of the walls, the size of the outflow area can be matched to the application.

Thus, in an advantageous embodiment, the outlet ends of the walls can lie in a curved surface, which can be, for example, a spherical or cylindrical surface. As a result, a very large outflow area can be created in a small space, with the ratio between the size of the outflow area and the size of the inflow area can be chosen large. The greater this area ratio, the greater the conversion of the dynamic energy of the air flow into pressure energy at the diffuser inlet. The large outflow area leads to a reduction in the air flowing out of the diffuser and thus to an increase in efficiency.

In another embodiment, the outlet ends of the walls can also lie in the areas of an imaginary square or a pyramid. This also results in a very large exit surface for a given installation space.

The entry ends of the walls can lie in a common plane.

In another advantageous embodiment, however, it is also possible for the inlet ends of the walls to lie in different planes, ie at different distances from the inlet cross section of the diffuser. Such a design of the diffuser leads to a particularly low-loss design.

If at least one opening is provided in at least one wall of the diffuser, through which adjacent passages of the diffuser are flow-connected to one another, flow separation in the corresponding passage can be prevented or at least delayed.

In this case, the opening can be a gap extending at least over part of the circumference of the corresponding diffuser wall. However, it is also possible to use recesses, punched-out portions or transverse slits as passages, in which case these different configurations of the openings can also be used in combination with one another on the inner wall of the diffuser. If the diffuser has more than one additional wall in addition to the outer wall, these openings can be provided in at least one of these additional walls, but also in two or more of the additional walls. Such openings can also be provided in the outer wall of the diffuser.

The fan according to the invention according to claim 13 has a diffuser which has an embodiment according to one of claims 1 to 12.

The fan according to the invention according to claim 14 is characterized in that the transitions at the outlet end between the sides of the wall have a curvature in a range of approximately <0.5×D. In this way, the transitions at the outlet end can be designed in such a way that optimal flow conditions result.

The curvature is advantageously in a range of about <0.25 x D.

In an embodiment of the fan according to claim 15, the exit surface of the wall with the rounded transition is smaller than the exit surface without a rounded transition at the exit end. The area deviation is in the range between about 1 and about 1.27, preferably between about 1 and about 1.05.

The fan with diffuser is designed in such a way that the transitions between the sides of the diffuser wall have a twist in the vertical direction, which follows the swirl of the air flow through the diffuser.

The fan can also be designed in such a way that the diffuser has the further wall, which has the round, preferably circular cross-section at the inlet, which continuously transitions into an angular cross-section over the height of the further wall.

The fan can also be provided with a diffuser, which is designed in such a way that the transitions between the sides of the further wall have a twist or twist in the vertical direction.

In another embodiment, the fan is provided with a diffuser having a wall that transitions across the height of the wall from a round inlet cross-section to an angular outlet cross-section, the transitions between the sides of the wall having a twist in the height direction have, which is designed taking into account the angle between the two radials as well as the diameter of the fan and the axial length of the diffuser.

The fan can also have a diffuser which is designed in such a way that the ratio of the inlet cross section to the outlet cross section is in a range of <approximately 5, preferably between approximately 1.2 and approximately 3.

Finally, the fan can be provided with a diffuser, the at least two walls of which are designed in such a way that the outlet end is at different heights to increase the outflow area.

The device according to the invention according to claim 16 is designed in such a way that the upper side of the housing side wall can be optimally used for the arrangement of the diffusers. At least two fans with diffusers are arranged on the top of the housing. These fans with diffusers can be arranged on any suitable side of the device housing.

The diffusers advantageously have an angular outlet cross section. The angular design makes it possible to place the several diffusers next to each other with only a small distance, so that in devices where only limited space is available and several diffusers are used, these can be arranged directly next to each other in one or more rows one behind the other. If the outlet cross-sections have a square outlet cross-section, adjacent diffusers can be arranged with their respective outlined sides either abutting one another or next to and behind one another with only the smallest spacing. As a result, the side of the housing is optimally used to delay the flow rate.

The outline shape of the diffusers at the outlet end is preferably based on the outline shape of the side of the housing on which the diffusers are provided. This allows the surface of the housing side to be optimally equipped with the appropriate diffusers be occupied, whereby the side of the housing can be optimally used accordingly.

Fig. 1

in perspektivischer Darstellung auf einem Gehäuse angeordnete erfindungsgemäße Austrittsdiffusoren von Ventilatoreinheiten,

Fig. 2

in perspektivischer und vergrößerter Darstellung einen nicht erfindungsgemäßen Austrittsdiffusor,

Fig. 3

eine Rückansicht des Austrittsdiffusors gemäß Fig. 2,

Fig. 4

eine Rückansicht auf einen erfindungsgemäßen Austrittsdiffusor,

Fig. 5

eine Draufsicht auf den Austrittsdiffusor gemäß Fig. 4,

Fig. 6

den Austrittsdiffusor gemäß Fig. 5 in perspektivischer Darstellung,

Fig. 7

eine Rückansicht des Austrittsdiffusors gemäß Fig. 4 mit einem Drall in den Wänden,

Fig. 8

die Abrundungen an den Übergängen zwischen den Seiten der Wände des Austrittsdiffusors und das Flächenverhältnis zwischen einem viereckigen und einem an den Enden abgerundeten viereckigen Auslassquerschnitt,

Fig. 9 und Fig. 10

jeweils im Axialschnitt zwei mögliche Befestigungen von erfindungsgemäßen Austrittsdiffusoren an Ventilatoren,

Fig. 11

in vereinfachter Darstellung eine weitere Ausführungsform eines erfindungsgemäßen Austrittsdiffusors,

Fig. 12

ein Gerät mit Ventilatoren nach dem Stand der Technik.

The invention is explained in more detail below with reference to some embodiments shown in the drawings. Show it

1

outlet diffusers of fan units according to the invention arranged on a housing in a perspective view,

2

in a perspective and enlarged representation of an outlet diffuser not according to the invention,

3

a rear view of the exit diffuser according to FIG 2 ,

4

a rear view of an outlet diffuser according to the invention,

figure 5

a plan view of the exit diffuser according to FIG 4 ,

6

according to the exit diffuser figure 5 in perspective view,

7

a rear view of the exit diffuser according to FIG 4 with a twist in the walls,

8

the roundings at the transitions between the sides of the walls of the exit diffuser and the area ratio between a square and a square outlet cross-section rounded at the ends,

9 and 10

in axial section, two possible attachments of outlet diffusers according to the invention on fans,

11

a simplified representation of a further embodiment of an outlet diffuser according to the invention,

12

a device with fans according to the state of the art.

1 shows a schematic representation of a housing 1 of a device 2, which is an example of a heat exchanger. In the exemplary embodiment shown, the device 2 is a standing device, but it can also be a device mounted on a wall, a ceiling or the like. The device 2 has a plurality of fans 3 which, for example, are arranged one behind the other in two rows with a small spacing. The fans 3 can be provided on the device with pressure or suction, or they can also be integrated into the device 2 .

The fans 3 each have an exit diffuser 4 (hereinafter referred to as diffuser) which minimizes exit losses by converting the velocity of the exiting air into pressure.

The diffusers 4 are provided on the rectangular top 5 of the housing 1 . In order to make optimal use of this rectangular top 5, the diffusers have 4 square outlines. This results in a particularly high increase in efficiency. The square shape results in a large exit surface for the exiting air. This also means that no flow separation occurs.

The diffusers 4 are arranged, for example, in such a way that their adjacent edges touch one another, as is particularly the case in 1 is shown.

Based on 2 a diffuser 4 is explained in more detail. It has an annular interface 6 with which the diffuser 4 can be connected to the fan. The outer edge 7 of the interface 6 is adjoined by a wall 8 which initially has a circular cross-section and at a distance from the outer edge 7 continuously changes into a quadrangular outline shape. The wall 8 has the quadrangular outline over part of its height.

As the drawings show, the corners of the walls 8 to 10 are rounded. Nevertheless, in the following we speak of a quadrangular outline shape. However, an embodiment is possible in which the corners at the exit end of the diffuser are really sharp.

In principle, the single wall 8 is sufficient as a diffuser wall for the diffuser 4 . In the embodiment after 2 two intermediate walls 9 and 10 are provided which are spaced apart from one another over their height, so that a passage 11 is formed between the two intermediate walls 9 and 10 . There is also a distance between the intermediate wall 9 and the outer wall 8 over the entire wall height, so that a further passage 12 for the air is formed between the two walls 8 and 9 . The passages 11, 12 have a square shape. The intermediate walls 9, 10 also have the transition from a circular interface 13, 14 to the square shape like the jacket 8, the square shape being to be understood in the same way as with the wall 8. The interfaces 13, 14 have a smaller diameter than the Interface 6, wherein the interface 14 of the inner partition 10 has a smaller diameter than the interface 13 of the central partition 9. The interface 14 advantageously has approximately the same diameter as the hub 21 ( 9 ) of the impeller 20.

The walls 8 to 10 are designed in such a way that the outline of the walls increases, preferably increases steadily, in the direction of their free end. The walls 8 to 10 thus have the largest outline at the free end.

The course of the walls 8 to 10 can be designed in such a way that they run at least approximately parallel to one another from the interface 6 , 13 , 14 . However, depending on the flow conditions, the walls 8 to 10 can also be designed in such a way that they do not extend parallel to one another.

In the embodiment after 2 two intermediate walls 9, 10 are provided. However, the diffuser 4 can also have only one intermediate wall or more than two intermediate walls.

The walls have 8 to 10 in accordance with the embodiment 2 same height so that their free ends lie in a common plane. However, the walls 8 to 10 can also be of different heights. For example, the height of the walls 8 to 10 decreases from the outside to the inside. However, two of the walls 8 to 10 can also be of the same height and the third wall can be higher or shorter than the other two walls. The height of the walls can thus be optimally adapted to the respective flow conditions in such a way that the outlet losses are minimized.

The intermediate walls 9, 10 are fixed to each other and to the outer wall 8 in a suitable manner, for example by means of cross members with which the walls are connected to one another.

The four pages 34 to 37 ( 7 ) of walls 8 to 10 continuously merge into one another. How out 4 shows, the transition takes place in such a way that the transition areas 15, 16 between the sides 34 to 37 of the wall 8 are curved over their height. This progression over the height of wall 8 is indicated by lines 15 in 4 marked. The transition area 15, 16 extends almost over the entire height of the wall 8. The curvature is provided in such a way that the transitions 15, 16 have a twist and follow the flow direction of the air behind the impeller (not shown) of the fan 3. How out 7 shows, the curvature is provided in such a way that the transition regions 15, 16 enclose an angle with a radial of the diffuser, which runs through the rounded corner 16 of the wall 8, over their length. Due to the course described, only very small flow losses through the transitions 15, 16 occur at most. Due to the curvature, the transitions 15, 16 follow the swirl of the air flow within the diffuser 4. The transitions 15, 16 extend approximately from the outlet end of the wall 8 to close to the circular outer edge 7 of the interface 6.

In the same way, the intermediate walls 9 and 10 are also provided with such transitions 17, 18, which are also designed with a twisting curve in accordance with the course of the air flow behind the impeller and extend from the transition areas between the sides of the partitions 9,10 to near the respective interface 13,14.

In the embodiment according to Figures 4 to 7 all walls 8 to 10 are provided with the curved transitions.

In the exemplary embodiments described, the walls 8 to 10 have a square outline. However, they can also have a rectangular, hexagonal or, for example, a triangular outline. The outline shape depends in particular on the shape of the corresponding side of the housing 1 on which the diffusers 4 are provided. The outline of the flow outlet can thus be selected so that the available side of the housing is optimally utilized.

9 shows the connection of the diffuser 4 to a nozzle 19 of the fan 3. The nozzle 19 has a circular outline. The fan 3 has the impeller 20 with the hub 21 from which the blades 22 protrude at regular intervals. They are advantageously each provided with a winglet 23 on the radially outer edge. The rear edge 24 of the wings 22 in the direction of rotation is tooth-like profiled.

The wings 22 of the impeller 20 can of course also have any other suitable design.

The diffuser 4 is radially connected to the nozzle 19 of the fan 3, preferably screwed, which is indicated by the dot-dash line 25.

The nozzle 19 is provided on a nozzle plate 32 which has approximately the same cross section as the free end of the wall 8 . The nozzle 19 and the nozzle plate 32 are advantageously formed in one piece with one another, but can also be separate components which are firmly connected to one another in a suitable manner. The nozzle plate 32 advantageously has the same angular outline as the outlet end of the wall 8. This allows the Fans 3 are arranged closely behind and / or next to each other. The nozzle plates 32 and the walls 8 of the diffusers 4 of adjacent fans 3 can collide here, as is shown in 1 is shown.

The diffuser 4 has the outer wall 8 and the intermediate walls 9, 10. In axial section, as can be seen from FIG 9 results in the sides of the outer wall 8 being approximately concave. The sides of the intermediate wall 9 are approximately straight in axial section, while the sides of the intermediate wall 10 are approximately convex. Such a design of the walls 8 to 10 can be provided in all of the exemplary embodiments described.

In the direction of flow behind the impeller 20 guide vanes 26 can be provided in the diffuser 4, which extend between the walls 8 to 10 and are rigidly arranged. The guide vanes 26 are located on the side of the radial attachment 25 facing away from the vanes 22 or, in the embodiment according to FIG 10 , the axial attachment. The diffuser 4 is pushed with its interface 6 onto or into the nozzle 19 and firmly connected to the nozzle by the radial attachment 25, which is advantageously a screw connection.

In the exemplary embodiments described, the walls 8 to 10 of the diffuser 4 can be designed to be noise-dampening, so that only a quiet operating noise is produced when the fans are in use. In the described embodiments, the walls 8 to 10 can also be designed to be adjustable, so that their outline shape can be adapted to the flow conditions and/or installation conditions at least over part of their height. The walls 8 to 10 can be designed to be flexible over at least part of their height, for example for adjustability.

10 shows the possibility of also fastening the diffuser 4 axially to the nozzle 19 of the fan 3. For this purpose, the interface 6 of the outer wall 8 can be provided with a radially outwardly extending annular flange 27 which is axially fastened to a radially outwardly extending annular flange 28 at the free end of the nozzle 19 . This axial fastening is also advantageous a screw connection that allows the diffuser 4 to be removed from the nozzle 19 if necessary.

The diffuser 4 can be made relatively short because of the partition walls. The air conveyed by the impeller 20 reaches between the walls 8 and 9 or 9 and 10. The flow cross section of the passages 11 and 12 initially decreases in the direction of flow until it has its smallest cross section in the region 29 indicated by a dashed line. The air is accelerated within this area 29, which leads to an equalization of the air flow. The air flow can then be delayed with fewer losses, resulting in a high degree of efficiency of the diffuser 4 . From the area 29, the flow cross section of the passages 11, 12 increases in the direction of the outlet end, preferably continuously. The narrowing of the cross-section 29 also prevents premature stalling of the flow (collapse of the flow) in the passage 11 and 12.

11 shows an exemplary and advantageous use of the diffuser 4. The inner partition 10 surrounds a terminal box 30 or a place for the electronics when an external rotor motor is used for the fan 3. In the case of an internal rotor motor, part 30 would be the fan motor. The air flow generated by the fan 3 flows through the passages 11, 12. The surface of the motor 30 is well cooled by the air flow flowing through the passage 11, as a result of which the electronics or electrical components of the motor are cooled effectively.

The outer wall 8 of the diffuser 4 is according to the embodiment 11 integrally formed with the nozzle 19. The exit area of the two passages 11, 12 is covered by a contact protection 31, which can be formed by a corresponding grid or by individual grid bars. The protection against contact 31 is at a large distance from the rotating impeller 20. The protection against contact 31 can be designed in such a way that only small pressure losses occur when the air exits the diffuser 4 and only a small amount of noise occurs. In particular, this effect can be achieved in that the contact protection 31 has a correspondingly large mesh size.

The contact protection 31 described can be provided in all of the described and illustrated embodiments.

The diffuser 4 of the exemplary embodiments described can be used for evaporators, condensers, air coolers, dry coolers and the like. How based on Figures 9 to 11 described, the diffuser 4 may be provided with a supporting function for accommodating the fan motor 30.

The fans 3 can be axial or diagonal fans.

The radius R at the exit end of the wall 8 ( 7 ) is advantageously in a range of <0.5 x D, where D is the diameter of the impeller 20 ( 9 ) is. In an advantageous design, the radius R of the rounded corners of the wall 8 is in a range of <approximately 0.25×D.

How out 8 shows, the exit surface of the wall 8 is smaller as a result of the rounding of the corners than with a square outline shape at the exit end. The area deviation A/A _R from the maximum available angular area A is in the range between about 1 and 1.27, preferably in a range between about 1 and about 1.05. By appropriately selecting the radius R of the rounded corner, an optimal exit cross section of the wall 8 of the diffuser 4 can be provided, so that the diffuser can be matched to the given installation conditions. In principle, the relationship described can also be applied to the walls 9 and 10 . The fillet does not have to be part of an arc of a circle (radius R), but can also have other shapes.

The efficiency of the diffuser can also be optimally adjusted to the given installation conditions by the ratio of the length L to the diameter D of the fan 3 . This length to diameter ratio L/D is in a range of <5, preferably in a range from about 0.2 to about 2. This ratio applies to all of the exemplary embodiments described.

The efficiency of the diffuser 4 can also be influenced by the selection of the inlet and outlet cross sections in relation to one another. In 9 the entry cross section is denoted by A _E and the exit cross section of the diffuser 4 is denoted by A _A . The ratio of exit area to entry area A _A / _AE is in a range of less than about 5, advantageously in a range between about 1.2 and about 3. The area ratio applies to all embodiments.

definiert, wobei der Winkel θ zwischen den beiden Radialen r₁ und r₂ gemessen wird. Die Radiale r₁ verläuft durch den Schnittbereich zwischen dem Übergangsbereich 15 mit dem inneren freien Rand 7 der Wand 8. Die Radiale r₂ verläuft demgegenüber bis zum in der Austrittsfläche liegenden Eckbereich der Wand 8, von dem aus sich der Übergangsbereich 15 erstreckt. Diese Verwindung bzw. dieser Drall $\mathrm{\theta }\times \frac{D}{L}$

liegt in einem Bereich zwischen 0° und 360°, vorteilhaft jedoch in einem Bereich zwischen etwa 50° und 100°.The based on the Figures 4 to 7 described twist or twist 15, 16; 17, 18 will be through the relationship $\mathrm{\theta }\times \frac{D}{L}$

defined, where the angle θ between the two radials r ₁ and r ₂ is measured. The radial r ₁ runs through the intersection between the transition region 15 and the inner free edge 7 of the wall 8. The radial r ₂ runs in contrast to the corner region of the wall 8 lying in the exit surface, from which the transition region 15 extends. That twist or twist $\mathrm{\theta }\times \frac{D}{L}$

lies in a range between 0° and 360°, but advantageously in a range between approximately 50° and 100°.

This relationship applies to all walls 8 to 10. The value can be the same for all walls, but can also differ from wall to wall.

Claims (19)

1. A diffusor having at least one wall (8), which encloses an inlet with round cross section, which transitions steadily over the height of the wall (8) of the diffusor (4) into an angular cross section at the outlet of the diffusor (4),
   characterized in that the transitions (15) between the sides (34 to 37) of the wall (8) have a twist in the height direction, which twist follows the swirl of the flow of the air through the diffusor.
2. The diffusor according to Claim 1,
   characterized in that the cross section of the diffusor (4) initially falls and then rises starting from an inlet end (6).
3. The diffusor according to Claim 1 or 2,
   characterized in that the angular cross section is provided over more than a quarter of the height of the wall (8) .
4. The diffusor according to one of Claims 1 to 3, characterized in that the diffusor (4) has at least one further wall (9, 10), which is surrounded by the wall (8) with spacing.
5. The diffusor according to Claim 4,
   characterized in that the further wall (9, 10) has an angular cross section at least at the outlet.
6. The diffusor according to one of Claims 4 or 5, characterized in that the further wall has a round, preferably circular cross section at the inlet, which steadily transitions into the angular cross section over the height of the further wall (9, 10).
7. The diffusor according to one of Claims 4 to 6, characterized in that the transitions (17, 18) have a twist in the height direction between the sides of the further wall (9, 10).
8. The diffusor according to Claim 1,
   characterized in that the transitions (15) have a twist (15 to 18) in the height direction between the sides (34 to 37) of the wall (8), which satisfies the relationship $\theta \times \frac{D}{L}$

   

   , wherein the angle (θ) is measured between two radials (r1 and r2), of which the one radial (r1) runs through the sectional region between the transition (15) and the free edge (7) at the inlet of the wall (8), whilst the other radial (r2) runs from the axis of the inlet up to the corner region of the wall (8) located in the outlet, from which the transition (15) extends, in each case as seen in the axial direction of the diffusor (4), and in that the twist lies in a range between approximately 50° and approximately 100°.
9. The diffusor according to one of Claims 4 to 7, characterized in that the wall (8) surrounds the further wall (9, 10, 38, 41) with formation of a passage (11, 12, 39, 40), and in that the outlet ends of the walls (8 to 10, 38, 41) are located at different heights to enlarge the discharge area (A_A) of the diffusor (4).
10. The diffusor according to Claim 9,
    characterized in that the outlet ends of the walls (8 to 10, 38, 41) are located in a curved area, such as a spherical area or cylindrical area (45).
11. The diffusor according to Claim 9,
    characterized in that the outlet ends of the walls (8 to 10, 38, 41) are located in planar areas, which are for example side surfaces of an imaginary parallelepiped (44) or a pyramid.
12. The diffusor according to one of Claims 9 to 11, characterized in that at least one opening (47, 48, 49) is provided in at least one wall (8 to 10, 38, 41), through which adjacent passages (11, 12, 39, 40)) are flow connected to one another.
13. A ventilator having an impeller (20) and a diffusor (4) according to one of Claims 1 to 12.
14. A ventilator having an impeller (20) and a diffusor (4) according to Claim 1,
    characterized in that the transitions (15) have a curvature (R) at the outlet end between the sides (34 to 37) of the wall (8), which lies in a range of approximately < 0.5 x D, preferably in a range of approximately < 0.25 x D, wherein (D) is the diameter of the impeller (20).
15. The ventilator according to Claim 14,
    characterized in that the outlet area (A_R) of the wall (8) with the rounded transition (15) is smaller than the outlet area (A) of the wall (8) without a rounded transition (15) at the outlet end between the sides (34 to 37) of the wall (8), wherein the area deviation (A/A_R) lies in the range between approximately 1 and approximately 1.27, preferably between approximately 1 and approximately 1.05.
16. A device having at least one ventilator according to one of Claims 13 to 15.
17. The device according to Claim 16,
    characterized in that at least one further ventilator (3) with a diffusor (4) is arranged on the upper side (5) of the housing side wall.
18. The device according to Claim 16 or 17,
    characterized in that the diffusors (4) have an angular outlet cross section.
19. The device according to one of Claims 16 to 18, characterized in that the outline sides of adjacent diffusors (4) adjoin one another.

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